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.