Typhoon Megi Slated For 2nd Landfall in East China; Taiwan not totally out of woods October 21, 2010

Note Typhoon Megi ragged, off-center eye at 18:30Z 10.21.10 on West Pacific Rainbow IR image (click for most recent loop)

Typhoon Megi JTWC Forecast Track 10.21.10

Typhoon Megi:  4 days ago, prior to then Super Typhoon Megi’s landfall on the Philippines, I had mentioned in my long term analysis that “… if the trof is fast and very deep, it could conceivably turn the storm north and then northeast.  While there may not be sufficient room in the sea for this to occur without striking land, that scenario would put Taiwan at risk of a hit from the Southwest…”  At the time, the forecast from the Joint Typhoon Warning Center called for the storm to track well to the Southwest of Hong Kong, perhaps toward the South China island of Hainan.  As it turns out the trof that was expected to turn the storm northwest was, in fact, deeper than forecast and Typhoon Megi turned North-Northwest not long after it emerged in the South China Sea. 

Typhoon Megi Visible Satellite 10.21.10

The damage from then Super Typhoon Megi to thePhilippines was largely to agricultural concerns. (Image Gallery) While the current agricultural outlook for the Philippines is stable, longer term consequences could result.  The loss of life was limited, considering that prior to landfall Megi had hit nearly 167 kts (190 mph) sustained winds with gusts to 220 mph.  It weakened a shade at landfall but was still an extremely strong super typhoon.  But, it moved across the island at a steady clip and had its greatest impact on less populated parts of the nation so flooding and loss of life was limited.

10.21.10 TPW image clearly shows Typhoon Megi nearing the Taiwan Strait (click for real time previous 72 hour loop)

Map of South China and Vicinity

At 15 UTC (Z) October 21, 2010 Typhoon Megi was about 250 nm southeast of Hong Kong moving North-Northeast at just 4 kts.  The trof in Southeast Asia dug so deep that it created a contraction in the steering ridge over the Western Pacific and the storm is now moving around the periphery of that ridge.  It is moving into cooler water which will hamper any further development but its got such a good outflow to the North that the decreasing intensity trend will be slower than what might otherwise occur.  Nevertheless, as it interacts with southwesterly flow aloft as it runs up along the trof to the northeast, it will begin to get ripped apart.  As I had mentioned a few days ago, if it weren’t for land getting in the way, this guy may have been a threat to Taiwan but the Chinese coast should get into the way. 

Note 7 day rainfall total related to Typhoon Megi ending 15 UTC (Z) 10.21.10 From NASA TRMM

In all likelihood, China will experience a weakening typhoon making landfall across the Taiwan Strait from Taiwan somewhere in between Shantou and Xiamen.  It is possible that the winds may have fallen to below typhoon strength by then.  I would think that the greatest concern would be for flooding as the storm, while dissipating, will have the potential to bring very heavy rains and the flooding threat will increase should the remnant of Megi move at a snails pace, which is not uncommon for a dissipating tropical cyclone.  Still, it is not totally out of the question that this guy gets so caught up in the trof that it tracks a bit more northeast, as some models suggest.  Should that occur, then Taiwan may be under the threat of a dissipating tropical cyclone from the Southwest.  As it stands, the time frame of ultimate landfall would be about 6 UTC (Z) October 23, 2010 and I suspect that would be the case if it follows the current forecast track or if it wandered farther north or northeast.

Weather Bottom Line: Our weather is lame. Nice…but lame.  Highs in 70’s lows in 40s  tonight.  A rain chance does show up by the second half of the weekend, but we’ll talk about that tomorrow.  Only caveat is that we had a little boundary come through and cooler drier air will filter in taking us down into the 30’s in some spots.  Frost possible in some areas but if the breezes persist, it may not get as chilly as some may think and the wind would also tend to limit frost.

Super Typhoon Megi Set To Strike Philippines With Extreme Intensity October 17, 2010

Super Typhoon Megi Cast an Impressive Multispectral Image at 2330Z Oct 16, 2010

For a more recent update regarding Typhoon Megi’s approach to China CLICK HERE

Japan Meteorological Agency Forecast Track Super Typhoon Megi (Juan)

The Philippines is making preparations ahead of a powerful Super Typhoon set to strike the island nation Monday morning with effects being felt on Sunday. The storm, known locally as Juan, is feared to have the same flooding potential as Typhoon Ketsana in Sept 2009. Typhoon Megi (a.k.a. Typhoon Juan) has behaved exactly as expected and it is now a very powerful storm designated as Super Typhoon Megi, Super Typhoon Juan or Super Typhoon 15W.  Whichever moniker you choose, it is a force to be reckoned with as its energy release compares favorably to an excess of the global electric generating capacity or as an equivalent to the largest yield atomic weapon every minute.  Another estimate puts a well developed tropical cyclone energy release on par with 500,000 Hiroshima style atomic bombs per day. 

Super Typhoon Megi Graph of Central Pressure Progression

In any event, the inhibiting factors to the storm have gone by the wayside as anticipated and the central pressure has dropped to 908 mb, which is extremely low.  To provide a frame of reference of how that compares to intense hurricanes in the North Atlantic,  Hurricane Camille in 1969 bottomed out at 909 mb and had winds approaching 200 mph.  Hurricane Andrew in 1992 had a minima pressure of 922 mb and the lowest that Katrina had in 2005, well before landfall, was 920 mb.   Super Typhoon Megi is not too far from the all-time lowest recorded atmospheric pressure which occured in 1979 with Typhoon Tip, which had a remarkable central pressure of 870 mb.  Previously, Typhoon Ida held the record of 879 mb when it was 750 miles east of Luzon (very close to the current location of Megi-450 miles NE of Manila) in 1958.  So, extremely intense storms in the region are not totally uncommon.  The clouds that had been obscuring the center have gone by the way-side and a well defined, relatively small eye has developed. 

West Pacific IR Rainbow Satellite Featuring Typhoon Megi-Click Image for Most Recent Loop

Super Typhoon Megi (Juan) JTWC Forecast Track 00Z 10.17.10

A pressure approaching 900 mb can easily support higher winds than the 3 UTC (Z) Oct 17 2010 analysis of 140 kt sustained winds of 140 kts and gusts to 170 kts, which translates to sustained winds of 161 mph or 259 kph and gusts to 195 mph or 315 kph.  Some further intensification is possible as the forecast calls for sustained winds to increase to 145 kts and gusts to 175 kts.  While the pressure can support even higher winds than that, at this point, they are so strong that it almost becomes academic in relation to the destruction potential and the ultimate intensity at landfall will most likely be subject to eyewall replacement cycles.  When a tropical cyclone goes through an eyewall replacement cycle, central winds typically fall off but the breadth of gale force winds expands.  That was the case with Hurricane Katrina which “only” had winds of 125 mph at landfall as it headed  into Mississippi but 100 mph winds were felt all the way to Mobile.  Another factor that may inhibit substantial intensification would be a slight disruption of the northern outflow.  This is an example of why it is difficult for an extremely intense tropical cyclone to maintain its maxima for long as environmental conditions must be perfect and perfect conditions rarely last long.  Nevertheless, as it stands, the official forecast from the Joint Typhoon Warning Center puts the winds around 140 kts at landfall sometime after 00 UTC (Z) October 18, 2010 north of Palanan and east of Tuguegarao.  It would not be out of the question for winds to exceed forecast levels at some point in time.  The timing of eyewall replacement cycles, however, is beyond current forecast abilities until the beginning of the cycle change is actually observed.

West Pacific Total Precipitable Water Latest 72 hours-Click Image for Loop

West Pacific IR Satellite with Wind Barbs (Isotachs)

As was anticipated, the trof of low pressure near Okinawa that was causing a weakness in the steering ridge to the North has moved northeast and the ridge filled in.  Consequently, the previous west northwest track of Megi has shifted westward at 12 kts.  The ridge is expected to continue to build such that the westward track should change around the time that the storm gets to the coast of Luzon such that it moves west-southwest.  That track would take Megi over the mountainous regions of northern Luzon but well north of Manila.  The storm surge on the eastern, northeastern and northern part of the island will be extreme but exact levels will be determined by the geogrpahy of the coast.  The mountains will enhance the rain totals which will most likely be extreme.  Even as it loses intensity rapidly over the mountains, the circulation will be such that there will be an onshore flow off of the South China Sea toward Manila for a period of time so rain totals will most likely be high on both sides of Luzon. 

Super Typhoon Megi Morphed Integrated Microwave Imagery with max Wind Velocity-Click Image for Loop

If there is any good news to report it is that the forward speed may increase a bit and so the center of the storm may be over Luzon for only about 12 hours.  That’s plenty of time to do plenty of damage but at least its not going to crawl across the Philippines and extend the high risk for catastrophic flooding.  By 12UTC (Z) October 18, 2010 Typhoon Megi should re-emerge over the ocean in the South China Sea with winds forecast to have been reduced to 95 kts.  However, once over the warm waters of the ocean, Typhoon Megi will regain some strength but most likely will not get back to it’s former self…that would be extremely rare and there simply will not be time nor will the environmental conditions support such a scenario.  Even so, It is expected to get back to 115 kt sustained winds by 00UTC (Z) October 22, 2010. 

Super Typhoon Megi Graph of Wind Speed Progression

Previously, the extended forecast track had suggested a second landfall on the South China island of Hainan followed by a final landfall after crossing the Gulf of Tonkin in Vietnam.  Modeling data though has formed a consensus though of another trof coming down through Asia. 

Map SE Asia

That trofiness is expected to influence Megi northwest after it enters the South China Sea.  The depth of that trof will determine the fate of Megi.  If it is slow or not so strong, then Megi may run into China south of Hong Kong, though it would still be close enough to affect that city.  If the trof is a little deeper, then it could turn Megi for a more direct affect on Hong Kong and if the trof is fast and very deep, it could conceivably turn the storm north and then northeast.  While there may not be sufficient room in the sea for this to occur without striking land, that scenario would put Taiwan at risk of a hit from the Southwest and potentially even Japan after that.  It’s way too soon to tell.  One thing seems invevitable:  the Northern Philippines will be affected adversely of the effects of a major tropical cyclone by 00UTC (Z) 18 October 2010.

Typhoon Megi Probable Super Typhoon Threatens Philippines October 16, 2010

23:30 UTC (Z) Rainbow IR image of Typhoon Megi Not totally impressive but it should become better defined over next 48 hours (Click image for most recent loop)

Typhoon Megi 17:30Z IR Satellite 10.15.10

CLICK HERE FOR MORE RECENT UPDATE ON SUPER TYPHOON MEGI

Typhoon Megi continues to intensify and is expected to be a significant threat to the northern Philippine province of Luzon by late this weekend.  Americares is making preparations to bring relief.   Typhoon Megi is currently the only tropical cyclone anywhere on earth but it could be one of the strongest of the year to affect land.  While it is very likely that the storm will go well beyond the threshold of Super Typhoon status with winds in excess of 100 kts, the specific track seems to be a little problematic and that could mean all the difference for the Philippines.  By 18 UTC (Z) October 17, 2010 the typhoon is expected to have sustained winds of 135 kts with gusts to 165 kts.  Roughly, that would be just shy of the North Atlantic Category 5 classification.  Environmental conditions are such that intensification from the 18 UTC (Z) October 15, 2010 95 kt level to the loftier, stronger classification is likely.  Megi is the name of a catfish in South Korea and is related to the feeling of getting wet, according to the Hong Kong Observatory

Equatorial Total Precipitable Water-Click Image for latest 72 hour loop As Typhoon Megi Develops

Typhoon Megi JTWC Forecast Track 18UTC (Z) 10.15.10 (click to enlarge)

Typhoon Megi was about 1000 miles east of Manilla at 18 UTC (Z) 10.15.10 moving WestNorthwest at about 17 kts with a central pressure of 955 mb which will in itself support higher winds than the current estimates.   The pressure trend has continued to be down.  The typhoon has been traveling around a big ridge of high pressure to the north but has taken the more northwesterly track over the past 24 hours due to a weakness in the ridge just south of Okinawa, Japan.  The general model consensus and analysis of the Joint Typhoon Warning Center is for that weakness to get squished out and the ridge reassert itself.  As that happens, Typhoon Megi will resume a more westerly course around the ridge.  However, previous forecasts had been calling for that turn more to the west to have already occured.  Since it has not, the landfall point on Luzon has been shifted farther north to somewhere near or north of Palanan and east of Tuguegarao.  The northern part of the island is very mountainous and the terrain is anticipated to do a number on the storm and it should rapidly fall apart with the land interaction.   However, the rising terrain of the mountains will provide for a lifting mechanism that will tend to enhance rainfall.  It is for that reason that in the Philippines and other island nations with central mountain ranges that flooding and mudslides are often the greatest threat as rainfall totals can be exceptionally extreme in a relatively short period of time.  Given the counterclockwise flow of a typhoon in the northern hemisphere, even locations on the other side of the island such as Laoag can expect and onshore flow from the north that will also provide adverse conditions of wind and heavy rain.

Typhoon Megi Morphed Intergrated Microwave Imagery 00Z 10.16.10 (Click for Loop)

The thinking now is that the storm will run across the northern part of the Philippines in 48-72 hours and lose much intensity, but not completely.  It is expected to re-emerge in the South China Sea as a 75 kt typhoon where it will continue west and regain some strength over the following day or so back to 90 kts.  From that point, it is expected to make a second landfall, perhaps on the South China island of Hainan.  From there, it could move across the Gulf of Tonkin and make a 3rd landfall in North Vietnam.  While it will certainly have lost considerable intensity by then, it is not uncommon for typhoons on the downside of life to prove a risk to life and property in Vietnam due to flooding concerns. 

Map SE Asia

I would think that the fly in the ointment is the weakness in the ridge.  It is caused by a shortwave trof that came off the Asian continent.  As mentioned it is forecast to be squished, or more correctly, it is expected to lift to the northeast as the ridge fills in.  However, if that trof does not lift out in a timely manner or slower than currently anticipated, then it is plausible that Megi proceeds on its current west northwest track a bit longer than forecast before making its turn more toward the west.  Should that happen to a great enough degree, then the typhoon could run over the islands in the Luzon Strait.  That would also bring Hong Kong into the picture as a potential threat to receive at least adverse effects of a major typhoon.

Bottom line is that this is going to be a serious typhoon.  It will affect the northern Philippines to some degree.  The current forecast calls for a landfall in Northern Luzon.  However, unanticipated but possible changes in the atmospheric conditions to the north that are steering the storm give rise to a degree of uncertainty as to the ultimate story of Typhoon Megi.

Typhoon Fanapi Set To Strike Taiwan Before Weekend is Over September 18, 2010

Click on Image for Most Recent Western Pacific Rainbow IR Image Loop

Typhoon Fanapi Forecast Track as per Joint Typhoon Warning Center

The people in Taiwan are anticipating the arrival of Typhoon Finapi.  Among other things, it is disrupting the fishing season that just started at the beginning of the month.  Perhaps more importantly, the Typhoon is packing winds that will cause concern for damage and a potentially devastaing surge.  However, the actual surge is determined by geograhpical features of the island as well as the physical features of the shelf and I am not aware of the physical features around Taiwan.  I cannot find any buoys in the region that are in operating condition but reports of 28 foot seas have been made.   While the forward speed of around 12 mph might limit the storm surge potential to a small degree, winds running at 105 kts (120 mph) will be sufficient to push a substantial amount of water up to the right of landfall.  Typhoon Fanapi’s intensity puts it as an equivalent of a category 3 hurricane.   Beyond the wind and surge threat, the topography of the island will serve to enhance rain totals and authorities are expecting up to 20 inches in some areas.  With a storm travelling around 10 mph, Typhoon conditions can be expected in several parts of the island for up to 8-12 hours.

Total Precipitable Water-Click on Image For Most Recent Loop

When you look at the satellite imagery, you find that Finapi is a well formed, compact tropical cyclone but the outflow to the north is almost absent while there remains some outflow to the south.  There is a big fat high to the north of the cyclone that is inhibiting the poleward outflow which may have inhibited the storm from becoming even more intense.   The central pressure of 935 mb has the potential to support winds higher than previous estimates.  Nevertheless, tropical storm force winds extend up to 150 miles from the center and typhoon winds some 35 to 40 miles from the center of circulation.   I suspect that there is the possibility that this storm may be getting slightly more intense as it approaches Taiwan for landfall as it appears that Fanapi has completed an eyewall replacement cycle.  An eyewall replacement cycle is a natural occurence related to a well developed tropical cyclone and typically, the maximum winds decrease as the storm goes through the cycle of replacing an eyewall, though the overall strong windfield expands.  Once the cycle is complete, then the storm returns to its previous intensity.  Hence, the satellite imagery suggests that the cycle is complete and Fanapi may be ramping up toward maximum potential just prior to landfall.

Fanapi IR Satellite 09.18.10 1732Z

For what it’s worth, Fanapi is the Micronesian name for “sandy islands” and it is expected to continue on its track generally to the west at around 10 kts and the Joint Typhoon Warning Center Forecasts points  to a landfall about 70 miles SSE of Taipei near the coastal town of Hualien.  Geographically speaking, it seems to me that the little bay to the north of Hualien may be vulnerable to an enhanced surge.  Once the storm makes landfall, the topographical features of Taiwan will disrupt the storm sufficiently that it will fall to below 100 kts when it re-emerges over the Taiwan Straits and will move into China within 36 hours with winds of around 80 to 85 kts about 150 miles Northeast of Hong Kong.  Inland flooding will be a concern for China as the storm dissipates, particularly when one considers that China has experienced flooding problems all summer long in many parts of the huge nation.

Cyclone Tomas Batters Fiji, Cyclone Ului Threatens Aussies March 16, 2010

Vis Sat SW Pacific 130Z 16 Mar 2010

Click S Pac 230Z 16 Mar 2010 Image for Most Recent loop

Tropics Heating Up?   For our part of the world, Hurricane Season comes each summer and fall from June 1 to November 30.  But, tropical cyclones show up in many parts of the world and are called different things.  Tropical cyclones in the eastern Pacific and North Atlantic are known as Hurricanes.  In the Western North Pacific, they gain the moniker of Typhoon. To become a typhoon or hurricane, a tropical cyclone must reach sustained winds of 64 kts or greater which is 74 mph.   In the South Pacific and Indian Ocean, they are called Cyclones but only need to reach 34 kts which is equivalent to the Tropical Storm designation in the North Atlantic of 40 mph.  If a tropical cyclone forms in the Timor Sea and moves Southeast across Northwest Australia, it is known as  a Willy Willy.   Now, tropical cyclones  have to form away from the equatorial regions…typically north, or south, of 10 degrees latitude.  That is because you need coriolis forces to produce circulation and the coriolis force becomes more negligible the closer you get to the equator.    Because coriolis parameters are at play and a tropical cyclone is an area of low pressure, the lower levels of the storm flow in a counter-clockwise direction in the Northern Hemisphere and in a clockwise direction in the Southern Hemisphere.

Tropical Cyclone Tracks 1985 to 2005

The average number of “named storms” in the North Atlantic is about 11 with 5 or 6 becoming Hurricanes.  Americans tend to think that active tropical weather is defined solely on what goes on in the North Atlantic but the truth is that the North Atlantic is not even close to the most popular breeding ground for tropical cyclones.  This tends to come into play these days when people look at tropical activity to determine the effects of Global Warming.  That would be short sighted.  The Eastern North Pacific averages 15 tropical cyclones,  The North Indian Ocean averages 6 tropical cyclones annually while the South Indian Ocean comes in with 11.  The Southwestern Pacific and Australia area checks in with 15 per year but the all time winner every year is the Western North Pacific.  That region of the world experiences more than 25 tropical cyclones per year with 18 becoming Typhoons.  The season in this hot bed of tropical cyclones is April to December but the frequency of off-season tropical cyclones in this region is much higher than any other part of the world.  Until recently, there had never been a tropical cyclone in the South Atlantic until a hurricane (that’s what they decided to call it) showed up off of Brazil in 2004. The map  at the left shows all tracks of all tropical cyclones from 1985 to 2005.

Tropical Cyclone Ului 12 z 15 Mar

Well, we are coming out of winter in the Northern Hemisphere but they winding up the summer in the South.  While it is speculated that the absence of land masses in the Southern Hemisphere is the reason why there are fewer tropical cyclones down South, it stands to reason that, like the Northern Hemisphere, the tail end of the summer months is probably the peak of cyclone season.  Right now, there is Tropical Cyclone Ului which is  in the Coral Sea and heading toward the Eastern Australian coast according to the Joint Typhoon Warning Center report on Ului .  Authorities in New Zealand are also keeping a close eye on Ului.   High pressure to the east has weakend and so Ului  is moving South but is expected to curve it back to the Southwest as high pressure builds back in once a trof moves through. As long as that happens, it’s the Aussie’s problem, not so much the Kiwis but it is uncertain if the storm makes it all the way to Queensland or just brushes the coast and swings back to New Zealand.  By that time, it should be in a weakening stage as it enters colder waters.  Well east of Ului is Tomas.

Cyclone Tomas JTWC Forecast 00Z 16 Mar

Now, Cyclone Tomas approached the Fiji Islands over the past 24 hours and has brought havoc.  Fiji has over 300 islands as part of its archpeligo with about 106 inhabited.  Vanua Levu is taking the brunt of the storm with winds with Tomas reported at 105 kts with 130 kt gusts by the Joint Typhoon Warning Center.   Video from Suva shows the rough seas and gusty winds, though though that city is well away from the center of the storm or its projected path.  It serves as testiment to how broad the windfield must be.   A report from the New Zealand Herald say there are reports of deaths and damage associated with Tomas with part of Fiji’s 1 million residents hunkering down in shelters.  Here is a more complete report that claims that both it and Ului are “fiercer than Katrina”  and it’s not too complete because communications are so poor and the storm is moving slowly.   The Fiji Meteorological Service has the latest updates and details.

Click on Precipitable Water 2:00Z 16 Mar 2010 Image for Loop and Notice how the storms rotate clockwise

Now, this report claims winds have increased to 200 km per hour. That would be 108 kts or 125 mph.  That is about the same maximum winds of Katrina, not stronger.  And Katrina’s devastation was caused by a storm surge that was enhanced by the local geography.  Further, Katrina had winds of 175 mph, or 281 km per hour, less than 24 hours prior to landfall that created a storm surge consistent with a top flight storm.  The only reason that the winds decreased at landfall was due to its going through an eyewall replacement cycle.  So, that claim is probably an exaggeration.  Nevertheless, it’s a tough storm and the surge  is apparently an issue.  Let us hope that the hyperbole is not the truth and that Fiji escapes. 

Sunday Morning Looks Lousy...Note Secondary Cold front to Northwest

NAM Wed Eve 700mb Moisture suggests we're on the edge of clouds which may inhibit temperatures

Weather Bottom Line:  I still see that upper low coming down from the north on Wednesday but so far, it appears to be content to move down to our west.  The question will be how much clouds we have in our area.  I still think it will be sufficient to keep us from getting to 60 but, either way, look for a warm up in the coming days.  Low to mid 50’s Tuesday with the sun making an appearance.  Filtered sun on Wednesday with highs in mid to upper 50’s. Low to mid 60’s on Thursday and Friday then mid 60’s, or maybe even higher on Saturday.  Then a cold front brings rain and some t’storms Saturday night and much cooler conditions on Sunday….I think it may be colder than most folks think…I say low to mid 40’s. We’ll see.

Remant of Typhoon Mirinae Moving Toward Vietnam; Leaves 14 dead, flooding in Philippines November 1, 2009

Note Mirinae and Developing Cyclone east of Philippines in loop

Philippines Def. Minister visits Barangay Callos in Laguna (click for photo gallery)

Typhoon Mirinae is well west of the Philippines(see discussion below).  Reports are that the number of deaths in the Philippines rose to 14 with significant flooding reported in numerous villages.  See CNN story and video here.   I still can’t get any reports concerning activity at Mount Mayon so I suppose that means it is behaving itself.  There is another tropical cyclone (see discussion below) trying to get going to the east of the Philippines.  A ship near the center of circulation (about 60 nm away) some 595 km east of Manila reported a pressure of 1007.5 mb which really isn’t that low.  I have yet to see any data that supports any huge development but the JTWC still gives the prospects of significant development at “fair.”  Since rain is the issue, I suspect that the biggest problem with this system is its very existance, which was noted several days ago on models.  At that time, the models called for this system to move west over the Philippines and so far, the system is following the guidance.  It has been observed moving west at 12 knots.  While this is not slow, it is of concern because if it continues at this pace and course, it may bring a good chance of rain, perhaps heavy rain for a decent amount of time over the Philippines in the next couple of days.

Typhoon Mirinae Forecast Track (downgraded to Tropical Storm)

Typhoon Mirinae has been downgraded to a tropical storm as it moves across the South China Sea on a west southwesterly course.  The official track calls for it to continue to move toward Vietnam and make a second landfall on the coast northeast of Ho Chi Minh City.  Recently, microwave imagery indicated an eye trying to reform and winds have increased to 50 kts.  However, the environment seems in the future to not be too favorable and the most recent observations indicate that the newly formed eye is already deteriorating.  Therefore,  Vietnam can expect a weak to moderate tropical storm making landfall just prior to 12Z November 2.  The remnant of the storm will continue toward Phnom Phen in eastern Cambodia where it may dissipate.  The danger is not done though because quite often the remnant of a tropical cyclone can produce an abundance of rain, as exemplified by Tropical Storm Claudette in the 1970’s and more recently Tropical Storm Allison in the Houston area, both of which caused horrific flooding along the upper Texas Coast. 

Microwave loop shows some attempt at development by Mirinae

WDPN32 PGTW 011500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 23W (MIRINAE) WARNING
NR 27//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
    A. TROPICAL STORM (TS) 23W (MIRINAE) WEAKENED TO 40 KNOTS AT
0600Z AND, ACCORDING TO RECENT DVORAKS FROM PGTW AND KNES, HAS
STRENGTHENED TO 50 KNOTS MORE RECENTLY. A 010955Z SSMI 37H MICROWAVE
IMAGE INDICATES A WEAK MICROWAVE EYE, WHICH GENERALLY CORRESPONDS TO
A SYSTEM GREATER THAN 45 KNOTS. GIVEN THE LARGE AREA OF CONVECTION
THAT HAS BUILT OVER THE LOW LEVEL CIRCULATION CENTER, THE INCREASED
DVORAK INTENSITY ESTIMATES, AND THE MICROWAVE EYE, THE INITIAL
INTENSITY HAS BEEN INCREASED TO 50 KNOTS. HOWEVER, CLOUD TOP
TEMPERATURES HAVE ALREADY BEGUN TO WARM SLIGHTLY AND THE CONVECTION
HAS BEGUN TO FLARE. A 011126Z SSMIS MICROWAVE IMAGE ALSO SHOWS THAT
THE MICROWAVE EYE FEATURE HAS ALSO BEGUN TO DEGRADE, AND OPEN UP ON
THE SOUTH SIDE. THESE OBSERVATIONS ARE INDICATIONS THAT THIS
INTENSIFICATION IS SHORT TERM, AND DUE POSSIBLY TO DIURNAL EFFECTS.
THE STORM CONTINUES TO TRACK SOUTH OF WEST TOWARDS VIETNAM UNDER THE
INFLUENCE OF THE SUBTROPICAL RIDGE TO THE NORTH.
3. FORECAST REASONING.
    A. THE FORECAST REASONING HAS NOT CHANGED SIGNIFICANTLY SINCE
THE PREVIOUS PROGNOSTIC REASONING BULLETIN WITH THE EXCEPTION OF THE
SHORT TERM INTENSIFICATION DESCRIBED IN PARA 2.A. THE STORM IS STILL
EXPECTED TO WEAKEN PRIOR TO MAKING LANDFALL WITH VIETNAM.
B.  TS 23W WILL BEGIN TO TRACK WEST-SOUTHWESTWARD AS IT TRACKS ALONG
THE SOUTHERN PERIPHERY OF THE MID-LEVEL SUBTROPICAL RIDGE TO THE
NORTH. THE NORTHEASTERLY COLD SURGE WILL STRENGTHEN OVER THE NEXT 12
TO 24 HOURS, WHICH WILL ACCOUNT FOR INCREASED VERTICAL WIND SHEAR
AND A MORE STABLE ENVIRONMENT. THESE FACTORS WILL CONTRIBUTE TO A
SLOW WEAKENING PRIOR TO MIRINAE MAKING LANDFALL WITHIN 24 HOURS. THE
STORM IS EXPECTED TO DISSIPATE OVER EASTERN CAMBODIA THERE AFTER,
THOUGH THE REMNANT VORTICITY MAY TRACK FURTHER WESTWARD (AS
INDICATED BY MANY OF THE OBJECTIVE AID MEMBERS) INTO THE GULF OF
THAILAND OR BAY OF BENGAL. REDEVELOPMENT OF THE LLCC DOES NOT APPEAR
PROBABLE IN EITHER CASE.//
NNNN

ABPW10 PGTW 010600
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND
/SOUTH PACIFIC OCEANS/010600Z-020600ZNOV2009//
REF/A/MSG/NAVMARFCSTCEN PEARL HARBOR HI/010152ZNOV2009//
AMPN/REF A IS A TROPICAL CYCLONE WARNING.//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
   A. TROPICAL CYCLONE SUMMARY:
      (1) AT 010000Z, TROPICAL STORM 23W (MIRINAE) WAS LOCATED NEAR
13.9N 115.4E, APPROXIMATELY 545 NM EAST-NORTHEAST OF HO CHI MINH,
VIETNAM, AND HAD TRACKED WESTWARD AT 12 KNOTS OVER THE PAST SIX
HOURS. MAXIMUM SUSTAINED SURFACE WINDS WERE ESTIMATED AT 40 KNOTS
GUSTING TO 50 KNOTS. SEE REF A (WTPN32 PGTW 010300) FOR FURTHER
DETAILS.
      (2) NO OTHER TROPICAL CYCLONES.
   B. TROPICAL DISTURBANCE SUMMARY:
      (1) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 14.6N
132.3E, IS NOW LOCATED NEAR 16.0N 131.2E, APPROXIMATELY 595 NM EAST
OF MANILA, PHILIPPINES. AN OCEANOGRAPHIC RESEARCH SHIP, CALL SIGN
MELVILLE, REPORTED 12-KNOT EASTERLIES AND SEA LEVEL PRESSURE AT
1007.5 MB AT 010000Z. MELVILLE IS LOCATED APPROXIMATELY ONE DEGREE
TO THE SOUTH-SOUTHEAST OF THE LOW LEVEL CIRCULATION CENTER (LLCC).
VARIOUS METSAT IMAGERY, INCLUDING A 312233Z SSMIS, INDICATES
PRONOUNCED CURVATURE OF THE CLOUDS PREDOMINATELY WITHIN THE
NORTHWEST QUADRANT. DESPITE THIS SIGNATURE THE LLCC IS DIFFICULT TO
LOCATE AND THE CONVECTION IS VERY WEAK OVERALL. THE MOST RECENT
SCATTEROMETRY DATA (NEARLY 18 HOURS OLD) INDICATE VERY STRONG
EASTERLIES TO THE NORTH OF THE LLCC, BUT LIGHT SUPPORTING WESTERLIES
TO THE SOUTH. THE UPPER LEVEL ENVIRONMENT REMAINS FAVORABLE WITH
LIGHT TO MODERATE VERTICAL WIND SHEAR, AND A JET MAXIMUM TO THE
NORTH AIDING (EASTWARD) VENTING. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1007 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS FAIR.
      (2) NO OTHER SUSPECT AREAS.
2. SOUTH PACIFIC AREA (WEST COAST OF SOUTH AMERICA TO 135 EAST):
   A. TROPICAL CYCLONE SUMMARY: NONE.
   B. TROPICAL DISTURBANCE SUMMARY: NONE.//

Typhoon Mirinae leaves flooding and death in Philippines as it heads to Vietnam October 31, 2009

Click on Image for most recent loop of Typhoon Mirinae

For latest news on death,flooding in Philippines and Mirinae track to vietnam(including microwave imagery) CLICK HERE

Click Image for latest Forecast Track of Typhoon Mirinae, now a tropical storm

Government run relief shelters in the Philippines are sure to swell in numbers from the effects of Typhoon Mirinae.   Typhoon Mirinae struck the main island of Luzon around 17 Z October 30 as the third typhoon to hit the Philippines in the past month.  Typhoon Lupit also brushed the northeast tip of the Philippines just a week ago.  Well over 100,000 Filipinos were still in shelters as a result of the flooding from Typhoon Ketsana and Typhoon Parma which struck back-to-back in late September and early October.  Many villages were still flooded from those two calamities that killed over 900.   The death toll in the Philippines from Typhoon Mirinae stands at a dozen and at least 15 villages are flooded with up to waist deep water.  This is on top of numerous villages that remained flooded from the previous storms.    The last report concerning Mount Mayon put the active volcano at a level two alert as just  prior to the landfall of Typhoon Mirnae, Mount Mayon had exhibited behaviour of increased activity.  Numerous earthquakes from the volcano accompanied minor eruptions of ash plumes but authorities had a dificult time making observations of a potential rising lava dome in the crater.

Watch 72hr loop of Total Precipitable Water Showing Movement of Typhoon Mirinae

Typhoon Mirinae has been downgraded to a tropical storm as it moves away from the Philippines at about 20 kts.  It is expected to continue moving west-southwest toward South Central Vietnam.  The official forecast calls for a second landfall just after 00Z November 2 a couple of hundred miles north of Ho Chi Minh City and continue towards Phnom Penh in Cambodia, though some models still call for a landfall a bit farther south to the east of Ho Chi Minh City.   A second tropical system has developed to the east of the Philippines and, while it is not expected to become a typhoon, the current track would take it over the Philippines in the next couple of days and would bring the threat of additional rainfall.  The system will be monitored for development.

Typhoon Mirinae Forecast: Philippines Landfall as Volcano Threatens Eruption October 30, 2009

Typhoon Mirinae Will Stirke the Philippines

Typhoon Mirinae 23:13Z Oct 29 Vis with low level wind barbs

Typhoon Mirinae will hit the Luzon province in the Philippines.  It’s possible that Mother Nature may also erupt a volcano at the same time.  The Typhoon Mirinae Forecast Track is very similar to that of Typhoon Ketsana.  The difference will be that it’s forward momentum will continue and therefore will not remain over the Philippines for an extended period of time. 

Typhoon Mirinae Forecast Track click for most recent map

The Typhoon Mirinae Forecast Track takes it into the Philippines almost due east of Manila and it re-emerges in the South China Sea almost due west of Manila.  There is some sense of continuity with the computer models.  The NOGAPS calls for a landfall at just around 12Z October 30 as a tropical cyclone with a central pressure a shade less than 992 mb.  The NOGAPS suggests that the center of circulation will be just west of Manila by 06Z October 31 with a pressure of something less than 1000 mb.  Now, the GFS is a bit different as it wants to weaken the storm prior to landfall to less than 1000 mb and has it exit as a 1004 mb low.  It too calls for a landfall in the neighborhood of 12Z October 30 with it moving offshore west of Manila by 6Z October 31.  A few days later, Mirinae is forecast to weaken somewhat over colder water in the South China Sea before making a second landfall in Vietnam before moving into Cambodia.   

Watch 72hr loop of Total Precipitable Water Showing Movement of Typhoon Mirinae

The official forecast track as of 00Z October 30 from the Joint Typhoon Warning Center calls for Typhoon Mirinae to make landfall east of Manila sometime between 12z and 18Z on October 30 and has it offshore of Manila by about 02Z October 31.  Other models must call for the faster speed as the NOGAPS and GFS call for the storm to be over land for about 18 hours whereas the boys at the JTWC are thinking more along the lines of 12 hours.  The folks in the Philippines will be hoping that the JTWC is correct because the faster pace will reduce the time of heavy rain over the island.  Still, several hours of heavy rain will be in the cards and winds will initially be running around 90 kts (100 mph) at landfall with higher gusts.  The storm’s forward speed will also mean that typhoon strength winds will be felt by everyone in the path of the center of circulation because, though weakened, it will still be a minimal typhoon when it moves back offshore in all liklihood.  Over 100,000 Filipinos remain in evacuation shelters from the effects of Typhoon Ketsana and Typhoon Parma which collectively killed over 900 people.  Many have been affected by the rapid spread of the disease known as Leptospirosis.  The government is warning for the potential for flooding and landslides so more people have been evacuated from vulnerable locations. 

Keep Up with latest 3 hour rainfall estimates from NASA's TRMM

If that is not enough for the Philippines….as Typhoon Mirinae makes landfall, Mount Mayon in the Philippines is making noises and there is a fear that Mount Mayon, the most active volcano in the Philippines may erupt while Mirinae is over the island or shortly thereafter.    The active volcano is one of many volcanic peaks in the Philippines and has been responsible for well over a dozen volcanic earthquakes and has begun spewing ash and sulpher dioxide into the air.  It last had an ash eruption on September 15.  Officials have been trying to get a look at the crater to determine if the dome forming there is indeed a lava dome or if its simply a case of magma below the surface pushing old rock to the surface.  Trouble is, they can’t make aerial examinations of the crater on top of Mount Mayon due to cloud cover and with the advance of Typhoon Mirinae, which the Philippines weather authorities designated as Typhoon Santi (why they have different names is a mystery to me), they won’t be able to make any observations.  So, Philippines Volcano Monitoring authorities  issued a level 2 alert warning the residents around the volcano and are enforcing a strict ban on people entering a zone around Mayon. 

Mayon one of many volcanoes in the Philippines

If they issue a  level 3 alert, then some 30,000 residents around the volcano will have to be evacuated.  There is great concern here because Mayon’s crater holds over 200,000 cubic feet of rocks.  There is fear of an eruption with lava flows.  Even of greater concern is the threat of a Lahar,the fast moving flow of mud, water and perhaps lava that can sweep down from volcanoes.  Heavy rains may enhance that threat and official say that in a worst  case scenario, they may have to evacuate some 300,000 people from Lahar zones.   However, Mount Mayon is pretty far south of the forecast landfall location.  Should Mirinae make landfall as the JTWC suggests, then the greatest rainfall should be well north of Mount Mayon.

WDPN32 PGTW 300300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 23W (MIRINAE) WARNING NR 17//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
    A. TYPHOON MIRINAE HAS TRACKED WEST-SOUTHWESTWARD AT 17 KNOTS 
OVER THE PAST 12 HOURS AND SUSTAINED AN INTENSITY OF 90 KNOTS. 
THOUGH THE CYCLONE STILL HAS SOME WESTWARD BLOWING CONVECTION, 
INDICATING THE PRESENCE OF EASTERLY VERTICAL WIND SHEAR, A SMALL 
ANTICYCLONE ALOFT HAS ENABLED CONTINUED RADIAL OUTFLOW. WHILE 
MIRINAE WAS PREVIOUSLY MAINTAINING A CENTRAL DENSE OVERCAST PATTERN 
THAT MADE POSITIONING USING INFRARED AND VISIBLE IMAGERY DIFFICULT, 
IT HAS RECENTLY STARTED TO DEVELOP MORE OF A BANDING EYE FEATURE. 
THEREFORE, IN COMBINATION WITH THE 292259Z 37 GHZ SSMIS MICROWAVE 
IMAGE, THE CURRENT POSITION IS PLACED WITH GOOD CONFIDENCE. 
SIMILARLY, THE CURRENT INTENSITY IS BASED ON CONSISTENT DVORAK 
ESTIMATES FROM PGTW, RJTD AND KNES OF 90 KNOTS. 
3. FORECAST REASONING.
    A. THE FORECAST REASONING HAS NOT CHANGED SINCE THE PREVIOUS 
PROGNOSTIC REASONING BULLETIN. 
    B. TYPHOON MIRINAE WILL CONTINUE TRACKING WESTWARD ALONG THE 
SOUTHERN PERIPHERY OF THE WELL-ESTABLISHED SUBTROPICAL RIDGE. THE 
SYSTEM IS EXPECTED TO MAKE LANDFALL IN CENTRAL LUZON AROUND TAU 18 
AND SLOW SLIGHTLY (BY APPROXIMATELY 2-3 KNOTS) IN FORWARD TRACK 
SPEED WHILE DECREASING BY 15 TO 20 KNOTS IN INTENSITY. AFTER TAU 24, 
MIRINAE IS EXPECTED TO ENTER THE SOUTH CHINA SEA ON A WESTWARD TRACK 
AND CONTINUE TO STEADILY WEAKEN UNDER THE INFLUENCE OF INCREASINGLY 
UNFAVORABLE VERTICAL WIND SHEAR ASSOCIATED WITH THE COMBINATION OF 
EASTERLY FLOW SOUTH OF THE SUBTROPICAL RIDGE AXIS (MID-LEVELS) AND 
NORTHEASTERLY FLOW INDUCED BY AN EARLY-SEASON COLD SURGE.
    C. MIRINAE WILL MAKE LANDFALL IN SOUTH-CENTRAL VIETNAM JUST 
AFTER TAU 72 AND WILL DISSIPATE OVER LAND AS A SIGNIFICANT TROPICAL 
CYCLONE BY TAU 96. THE MODEL GUIDANCE IS IN GOOD AGREEMENT WITH A 
SOUTHWESTWARD TRACK THROUGH THE SOUTH CHINA SEA. HOWEVER, SOME OF 
THE MODEL AIDS, INCLUDING THE JAPANESE SOLUTION, TAKE THE SYSTEM 
JUST SOUTH OF MANILA, PHILIPPINES AND TOWARDS HO CHI MINH CITY, 
VIETNAM.//
NNNN

Typhoon Mirinae Forecast Track Points to Luzon, Philippines Landfall at end of week October 29, 2009

Typhoon Mirinae Appears Certain to Strike the Philippines

For news of flooding, deaths in Philippines and Mirinae track to Vietnam CLICK HERE

Typhoon Mirinae Forecast Track click for most recent map

The Typhoon Mirinae Forecast Track remains generally unchanged as does the intensity.  It continues to move west at a pretty good clip and that may end up being a good thing for the Philippines.   The JTWC forecast track has been nudged a tad farther south than previous runs which would send the typhoon across the island closer to Manila.  While Luzon really can’t handle a lot of rain, it’s going to get it as well as winds along the coast perhaps as high as 105 to 110 mph or 95 kts with higher gusts.  With the forward momentum of Mirinae, I suspect that whatever the maximum storm surge in that area with this type of storm will be likely.  The biggest difference between the NOGAPS and GFS models is the timing.  Over 117,000 Filipinos remain in shelters as a result of Typhoon Parma and Tropical Storm Ketsana.  So, the government of the Philippines is warning the potential for  landslides and flooding.  The government is particularly concerned because All Saints Day, November 1, is traditionally a day when Filipinos visit cemeteries to remember ancestors.

Typhoon Mirinae Satellite Loop Click for most recent loop

The NOGAPS advertises a typhoon moving at a pretty good pace with a landfall outlined just prior to 12Z on Friday October 30.  It also favors a landfalling tropical cyclone with a central pressure a shade less than 996 mb.  The GFS on the other hand doesn’t come up with as robust a system as the NOGAPS.  The central pressure at landfall is something between 996 mb and 100 mb.  If that is verified, I find it hard to determine how a storm with that level of pressure could support the JTWC contention that a 95 kt typhoon will strike the Philippines.  My experience tells me that pressures that high generally does not support winds of 95 kts unless it was a major tropical cyclone that was winding down and even that is not evidence of support.  Falling winds mean that the pressure cannot support that wind level.    Other than that, the GFS is much slower than the NOGAPS with a landfall with a landfall not coming until just after 00Z on Saturday Oct 31.  That is a big difference because if Mirinae moves that slowly then it would be dropping heavy rain on the Philippines for many hours longer than the NOGAPS solution. 

Typhoon Mirinae Water Vapor Loop click for most recent loop

The typhoon has been moving at a steady speed and so unless something shows up to slow its forward speed then it seems reasonable that the JTWC forecast of having the core of the storm over Luzon for less than 24 hours is very plausible.  On the other hand, that also means that the fine folks of Manila and other parts of the Philippines will probably experience pretty decent winds….maybe even typhoon force…for the duration of the storm because Mirinae just wouldn’t have time to fall apart…but it will weaken.  This storm got stronger than anticipated due to a trof to the north that was enhancing the outflow to the north.  Interestingly, that trof was actually created from the remnant of Typhoon Lupit which moved northeast offshore of Japan, turned extratropical and created a front trailing off from it.  With that feature moving out,  there isn’t any real mechanism that would help enhance the intensity substantially.  The only thing that will help it get stronger is an increasing outflow aloft, but that will be offset somewhat by a little bit of vertical shear.  The JTWC notes that the shear has already messed up the visibility of the eye. 

Watch 72hr loop of Total Precipitable Water Showing development of Typhoon Mirinae

If one assumes a rapid movement across the Philippines, then one might assume that the storm will not deteriorate that much over land and will emerge in the South China Sea in good shape.  So good that it may redevelop.  But, sea surface temperatures in the central South China Sea have dropped off a bit due to a recent shot of unseasonably cold air in the area.  So, the JTWC forecast reflects that situation by reducing the intensity of the storm as it approaches Vietnam.  Mirinae may fall to tropical storm status before landfall.  However, Vietnam also suffered from Typhoon Ketsana and Typhoon Parma, though Parma was closer to Hanoi.  In any event, the ground in Vietnam is pretty saturated so if they get a tropical storm instead of a typhoon, it is really immaterial as the forward motion will be the key for Vietnam.  Vietnam suffered over 3/4 of a billion US dollars just from Ketsana.   If the storm slows down once it’s inland over SE Asia, then excessive rainfall can be anticipated.  The thing that everyone wants is for the storm to keep moving. 

WDPN32 PGTW 290300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 23W (MIRINAE) WARNING NR 13//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
    A. TYPHOON (TY) 23W (MIRINAE) HAS INTENSIFIED TO 90 KNOTS AND
MAINTAINED A WESTWARD TRACK UNDER THE INFLUENCE OF THE SUBTROPICAL
STEERING RIDGE OVER THE PAST 12 HOURS. RECENT ANIMATED MULTISPECTRAL
IMAGERY SHOWS EVIDENCE OF EASTERLY VERTICAL WIND SHEAR THAT HAS
CAUSED MIRINAE TO LOSE ITS EYE-LIKE FEATURE OVER THE LAST 12 HOURS.
HOWEVER, THE SYSTEM STILL HAS GOOD POLEWARD OUTFLOW INTO THE MID-
LATITUDE WESTERLIES AS WELL AS ACCESS TO POLEWARD OUTFLOW INTO THE
TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) LOCATED APPROXIMATELY 15
TO 20 DEGREES EAST OF THE SYSTEM. THE CURRENT POSITION IS BASED WITH
HIGH CONDIFENCE ON POSITION FIXES BY RJTD AND PGTW AND IS SUPPORTED
BY A 282127Z SSMI MICROWAVE IMAGE. THE CURRENT INTENSITY IS BASED ON
DVORAK ESTIMATES OF 90 KNOTS FROM PGTW AND RJTD.
3. FORECAST REASONING.
    A. THE FORECAST REASONING HAS NOT CHANGED SINCE THE PREVIOUS
PROGNOSTIC REASONING BULLETIN.
    B. THE TYPHOON WILL CONTINUE TO TRACK WESTWARD THROUGH THE
FORECAST PERIOD AND WILL RETAIN RADIAL OUTFLOW, ENABLING EXHAUST
INTO THE MID-LATITUDES, AS IT TRACKS SOUTH OF A NARROW SUBTROPICAL
RIDGE. FURTHER INTENSIFICATION IS EXPECTED TO BE LIMITED, MAINLY DUE
TO THE LACK OF A STRONG (POLEWARD) OUTFLOW CHANNEL AS THE SYSTEM
TRACKS FURTHER AWAY FROM THE TUTT MENTIONED IN PARA 2.A. MIRINAE IS
EXPECTED TO MAKE LANDFALL IN THE PHILIPPINES AND WEAKEN JUST BEFORE
TAU 48.
C. BEFORE TAU 72 THE SYSTEM WILL EXIT LUZON INTO THE SOUTH CHINA SEA
AS A MUCH-WEAKENED TYPHOON. A COOLER POOL OF SEA SURFACE TEMP-
ERATURES IN THE CENTRAL SOUTH CHINA SEA, MINIMAL OCEAN HEAT CONTENT
VALUES AND DIMINISHED POLEWARD EXHAUST WILL PROMOTE STEADY
WEAKENING. AN EARLY SEASON COLD SURGE WILL ALSO AID IN WEAKENING THE
SYSTEM CLOSER TO TAU 96. THE MODEL GUIDANCE IS IN STRONG AGREEMENT
WITH THIS FORECAST SCENARIO. THEY ALSO SHOW A GROWING TREND TOWARDS
A MORE SOUTHWESTERN TRACK IN THE EXTENDED TAUS.//

blogarama.com

Typhoon Mirinae Forecast Track Toward Flood Plagued, Disease Infested Portion of Philippines October 28, 2009

Typhoon Mirinae IR Color Satellite-Click image for most recent loop

Get most recent update on Typhoon Mirinae forecast track and latest on potential for volcano eruption as Mirinae strikes the Philippines, CLICK HERE

Watch 72hr loop of Total Precipitable Water Showing development of Typhoon Mirinae

Typhoon Mirinae was born from the developing Tropical Storm 23W, as expected.  The storm has been moving along at a pretty good clip. So far it has tended to move faster than the general forecast.  I suspect that is why the Joint Typhoon Warning Center has gone along with the early forecast landing in the Philippines at around 12Z October 30 that is brought out by the NOGAPS model.  The GFS is remarkably similar to the NOGAPS in the track and intensity with both advertising a tropical cyclone with a central pressure somewhere between 992 and 1000 mb near the same location in the Luzon province that Typhoon Parma struck.  But, the GFS wants to take the storm into the Philippines somewhere between 12z and 18z October 31.  Given the persistent forward speed and little evidence that there is much out there to slow this guy down, the early forecast landfall is probably a fair bet. 

Typhoon Mirinae Forecast Track Updates Regularly-Click on Image

Tropical Storm 23W not only has been moving faster than forecast, it also has developed faster than forecast.  It was not anticipated by the JTWC to become Typhoon Mirinae until 12Z October 28 but had done so by 18Z October 27.  That is not overly significant except that it is obviously in a upswing mode.   The risk here is that with the storm’s forward speed and the fact that its in an intensication process, odds are pretty high that the Philippines will be struck by a tropical cyclone that is intensifying, not weakening.  One thing that has been right on the money is the forecast track.  Typhoon Mirinae moved northwest south of Saipan near Andersen Air Force base  while it was still Tropical Storm 23W.  As anticipated,  the storm went a few hundred more miles on that course and now has taken a more westerly track.  The good news is that the forward speed that it is showing and that is forecast will mean that it would cross the Philippines in less than 24 hours.  That would tend to cut down on excessive rain, though very heavy rain in a short period of time can be expected. 

Typhoon Mirinae Vis Sat w/low level wind barbs 23:13Z 10.27.09

The  bad news is that Luzon cannot handle much in the way of heavy rain.  The storm flow will be slamming into the same mountainous regions that experienced mudslides from Typhoon Parma and Tropical Storm Ketsana and those mountains will do nothing but enhance the rainfall rates.  If the forecast holds and verifies, then Typhoon Mirinae will hit in almost the exact same spot at Typhoon Parma and will track due west near Manila, similar to Tropical Storm Ketsana.  Also, the forward momentum and expected maximum winds of 100 kts would create a pretty good storm surge to the right of the center of the landfall, which is something that did not occur with either Typhoon Parma or Tropical Storm Ketsana.  The flood ravaged Philippines is no where close to recovering from Parma and Ketsana as disease has now broken out in Luzon.  The World Health Organization is helping to try and control an outbreak of  leptospirosis and if Mirinae does as expected, the situation will do nothing but get worse.

Typhoon Mirinae Water Vapor Loop-click image for most recent loop

There is one more bit of bad news that could prove to be the biggest factor in the saga of the Philippines.  When I looked beyond the landfall time of Typhoon Mirinae, I noticed that the typhoon moves across the South China Sea into Vietnam, which means the exact same areas that got hit by Ketsana in both the Philippines and Vietnam will get nailed again and some of the areas affected in Vietnam by Parma will also get heavy rains and wind from Mirinae.  But, maybe more importantly I noticed another tropical cyclone right on the heels of Typhoon Mirinae.  It is not that well developed at only about 1008 mb.  But, both the NOGAPS and the GFS show this feature and it is forecast to track right into Luzon.  Often, a weak tropical cyclone can bring extremely heavy rains.  Since they are not well developed, they don’t necessarily follow typical steering trends and often times will slow down and fall apart over one area, dropping a lot of rain.  This scenario is many days away if it were to occur, but it is showing up on at least two models. So, its’ worth noting.

WDPN32 PGTW 280300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 23W (MIRINAE) WARNING NR 09//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
    A. TYPHOON (TY) 23W (MIRINAE) IS TRACKING WESTWARD OVER THE PAST
12 HOURS AND HAS RAPIDLY INTENSIFIED TO 75 KNOTS. DVORAK ESTIMATES
FROM PGTW, KNES AND RJTD CURRENTLY SUPPORT INTENSITIES FROM 75 TO 90
KNOTS. THIS FORECAST IS PRIMARILY BASED ON THE PGTW AND RJTD
ESTIMATES. MICROWAVE IMAGERY OVER THE PAST 12 HOURS HAS SHOWN A WELL
DEFINED EYE HAS DEVELOPED, AND IS BEGINNING TO BE APPARENT IN
MULTISPECTRAL IMAGERY AS WELL. THE POLEWARD OUTFLOW CHANNEL HAS
REMAINED WELL ESTABLISHED OVER THE PAST 12 HOURS WITH THE MID-
LATITUDE TROUGH NORTH OF TY 23W THAT HAS STARTED TO LIFT OUT TO THE
NORTHEAST. STRONG ZONAL FLOW ACROSS SOUTHERN JAPAN IN THE UPPER
LEVEL HAS STARTED TO REPLACE THE TROUGH AS THE PRIMARY MECHANISM FOR
POLEWARD OUTFLOW. THE COMBINATION OF THE TROUGH AND DEVELOPING ZONAL
FLOW HAS SUPPORTED THE RECENT INTENSITY CHANGE OBSERVED. RADIAL
OUTFLOW, ASSOCIATED WITH AN UPPER LEVEL POINT SOURCE ANTI-CYCLONE
LOCATED TO THE EAST OF TY 23W, HAS MAINTAINED AN EQUATORWARD OUTFLOW
CHANNEL OVER THE PAST 12 HOURS.
3. FORECAST REASONING
    A. THE FORECAST REASONING HAS NOT CHANGED SINCE THE PREVIOUS
PROGNOSTIC REASONING BULLETIN.
    B. TY 23W WILL MAINTAIN A GENERAL WESTWARD TRACK TOWARDS LUZON
THROUGH TAU 72 UNDER THE INFLUENCE OF A WELL ESTABLISHED MID-LEVEL
SUBTROPICAL RIDGE (STR) LOCATED TO THE NORTH OF MIRINAE. OUTFLOW
FROM THE MID-LATITUDE TROUGH AND ZONAL FLOW WILL DIMINISH SLIGHTLY
OVER THE NEXT 24 HOURS, BUT CONTINUED RADIAL OUTFLOW WILL ALLOW FOR
STEADY INTENSIFICATION THROUGH TAU 72. THE INTENSIFICATION WILL BE
SUPPORTED BY LOW VERTICAL WIND SHEAR CONDITIONS PERSISTING THROUGH
THE ENTIRE FORECAST, ALONG WITH FAVORABLE SEA SURFACE TEMPERATURES
AND OCEAN HEAT CONTENT.
    C. BEYOND TAU 72 MIRINAE IS EXPECTED TO MAKE LANDFALL WITH
LUZON, WEAKEN AND SLOW SLIGHTLY DUE TO THE LAND INTERACTION, THEN
CROSS INTO THE SOUTH CHINA SEA AROUND TAU 96. AS THE SYSTEM RE-
CONSOLIDATES THE INTENSITY IS EXPECTED TO REMAIN STEADY THROUGH TAU
120. MODEL GUIDANCE IS IN GOOD AGREEMENT WITH THE FOLLOWING
FORECAST, EXCEPT WITH THE SPEED OF ADVANCE OVER LUZON. MODELS
SUGGEST LITTLE TO NO SLOW-DOWN AS TY 23W CROSSES OVER LUZON. THE
FORECAST INCORPORATES A DECREASE IN TRACK SPEED FROM TAU 72 THROUGH
120 BASED ON LAND INTERACTION WITH THE LOW LEVEL CIRCULATION.//
NNNN