Hurricane Earl Set For Brush With US Coast From Hatteras to Cape Cod September 2, 2010

Hurricane Earl IR Rainbow Image 1915Z 09.02.10 Click for real time loop

Hurricane Earl Spaghetti Model 18Z 09.02.10

If you recall a few days ago I had talked about the challenges for Hurricane Earl maintaining its ferocity.  One of the main concerns that I had was a huge amount of dry air that Earl was getting ready to move in to.    I was a bit surprised that the NHC didn’t mention it more often and it appeared that Earl was able to fend off the dry air.  However, it seems apparent now that dry air did indeed work its way into the storm and Earl rapidly decreased in intensity on Thursday evening.   The dry air intrusion seems to have coincided with what so often seems to be the case which is that Hurricane Earl began an eyewall replacement cycle during the late morning on Thursday, prior to a potential Outer Banks of North Carolina landfall.   Most likely, Earl yesterday reached its maxima when it topped out at 145 mph with gusts to 165 and a central pressure somewhere in the neighborhood of 930 mb.  If you look at the satellite loop, you will note that the eye seems to fill in.  That was not an indication that the storm is dying, but instead was indicative of a very healthy hurricane.  What typically happens with an eyewall replacement cycle is that the maximum winds near the eye decrease somewhat, but the overall energy gets dispersed throughout the storm.  Hence, a broader field of strong winds results.  At 3:30 PM EDT Earl essentially had two eyes.  The old eye was collapsing and a new, much larger,  eyewall was developing around it.  So, winds decreased and the pressure rose to 943 mb but its a much larger storm.  By 5 pm Earl’s maximum winds had dropped to 115 mph and the pressure was up to 947 mb.   We saw that with Hurricane Katrina.  As it made landfall, the winds dropped off to 125 mph in far western Mississippi and near the mouth of the Mississippi River yet, all the way east over to Mobile, AL winds were in excess of 100 mph.  So, regardless of exactly where the eye of the storm runs in relation to North Carolina, the winds on the Outer Banks and even for some distance inland will be hazardous.

Hurricane Earl Spaghetti Model Intensity Forecast 18Z 09.02.10

On Thursday afternoon, another potential problem was that, if the replacement cycle was complete before it got to North Carolina, then it could have been in a re-intensification stage and perhaps deepening back toward a category 4 hurricane.   At this point, that is not only unlikely but also rather irrelevant.  As of 3:30 pm EDT on Thursday, Earl was moving at about 355 degrees, or just slightly west of due North.  It had crossed just west of 75 degrees West Longitude.  Cape Hatteras is at 75 degrees 15 minutes W. Long and 35 degrees 30 minutes North Latitude.  I believe that there is a fair chance that Cape Hatteras will take a direct hit though if Earl is just off shore, then it could be in the western eyewall.  If you look closely at the 2PM forecast discussion, the NHC forecast position at 2AM is 75 degrees West Long and 33.5 degrees North Lat, or right over Cape Hatteras.  At two AM on Saturday, the storm is forecast to have maximum winds of nearly 100 mph and is located at 40.o N and 75.8 W or almost exactly over Marthas Vineyard.   Keep in mind a wobble to the right by 25 miles would spare the eye passing over these locations but it would still be close enough to be potentially destructive.  By 8PM EDT Earl’s maximum winds had decreased to 110 mph and the liklihood of the trend of winding down is rapidly diminishing.  It would appear from the satellite depiction that upper shear is starting to work on Earl as well as dry air from the Eastern United States.

N. Atlantic IR 1945Z 09.02.10 Click For real time loop

Hurricane Earl NHC Forecast Track 2PM 09.02.10

Once it passes Cape Hatteras, three things will start to work in conjunction to turn it North Northeast and then Northeast.  First, there is the Coriolis Force, which is the force that wants to turn a cyclone to the right of its path in the Northern Hemisphere.  That force increases as the storm moves poleward.  Then there are the mid lattitude prevaling westerlys.  That is the general persistent wind flow in the mid lattitudes of the Northern Hemisphere.  Finally, there is a frontal boundary that is progressing Eastward.  As of 3:30 PM EDT it was just west of the Ohio Valley.  That is some distance from the coast and not moving as fast as we might like.  But, as it approaches, winds ahead of the front or trof will increase from the Southwest.  That will increase Earl’s forward speeed and also serve to knock up the upper air support of the hurricane.   As mentioned earlier, by 8PM EDT the satellite imagery appears to indicate that the southwesterly shear was already taking a toll on Earl.

Structure of a hurricane

Essentially, a hurricane is a warm-core area of low pressure that is a giant heat engine, drawing its energy from warm ocean water.  The ocean has to be at least 80 F.  Not every surface low over the ocean becomes a hurricane though.  It is essential that a hurricane get what I call a “hat” or an anticyclone aloft.  That would be a big area of high pressure.  That is why when you look at a satellite loop, you see clouds going clockwise, yet at the surface, the hurricane winds go counter clockwise.  The upper level high serves to vent the storm.  The structure of a hurricane is such that, at the surface, the flow is toward the center in a counter clockwise fashion.  When the air reaches the center it has nowhere to go but up.  Aloft, the high pressure features air that sinks and goes outward in a clock wise fashion.  The high aloft helps push out the rising air below and as it does, it allows for a more even flow of air rising from below.  When these winds from the southwest kick in, it will disrupt the ventiing flow aloft which will limit the rising air below.  All of that should start to occur in earnest once Earl gets past the Outer Banks.  At that same time, it will start to cross over water that is either near or below 80 F and eventually will get over water that is definitely too cold to support a tropical system.

Atlantic Sea Surface Temperatures-Click for Loop

So, look for rapid weakening of the storm beginning off the North Carolina coast and thereafter.  It will also lose its tropical characteristics probably before it gets to Cape Cod.  Nevertheless, winds of at least hurricane force will continue as the storm moves north.  The forecast track takes it very close to Long Island and even over Cape Cod.  While it may lose its hurricane classification, it will also provide a very healthy storm surge and a high tide will only aggravate the situation.  Click here to find the storm surge forecast for your location.  The storm will also be moving very very quickly so, on the one hand, the effects will not last as long but the conditions will also deteriorate very rapidly.  No one can tell with exact certitude where the center of Earl will travel.  That should not surprise anyone when one considers that the earth is 25,000 miles around;  a margin of error of say 50 miles represents just a fraction of a percent but, it can be the difference between terrible conditions and horrific conditions.  Most of the time, people who try to ride out a storm vow they will never do so again.  Sometimes, they lose their lives and by that time it is obvious they made a mistake.  With hurricanes you do not get a second chance.  Getting out of the way is the better part of valor.  Also, Earl’s interaction with the front may enhance rain fall inland greatly.  Flooding will be a concern from not only the surge, but also rainfall.

N. Atlantic Basin Total Precipitable Water Image-Click For Loop That Clearly Indentifies Cyclone in the N. Atlantic

Gaston NHC Forecast Track 2PM 09.02.10

Gaston Spaghetti Model 18Z 09.02.10

Behind Earl is Fiona which should not be an issue for the United States and perhaps no one.  What is of greater concern is Tropical Storm Gaston.  It is much farther south than Danielle was, or Earl or Fiona.  Fiona will get picked up by the same trof that is picking up Earl and Danielle also got picked up by a trof.  But, Gaston is so far south that it will most likely sneak under any trof and westerly flow around  an Atlantic high should drive Gaston in a westerly fashion.  Most models put Gaston either near or South of the Dominican Republic in about a week and most develop it into a hurricane.  It will not be traveling over any water that has been worked over by Danielle, Earl or Fiona so it should be plenty warm enough and conditions should be conducive for development, perhaps even enough to support a major hurricane.  Its location will offer scenarios for it to enter the Gulf of Mexico as well as potentially affecting the East Coast. 

HURRICANE EARL DISCUSSION NUMBER  34
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072010
500 PM EDT THU SEP 02 2010

DATA FROM A RECONNAISSANCE PLANE INDICATE THAT EARL HAS WEAKENED A
LITTLE BIT THIS AFTERNOON.  THE CENTRAL PRESSURE ROSE TO 947
MB…AND A BLEND OF THE SFMR MEASUREMENTS AND FLIGHT-LEVEL WINDS
SUGGEST THAT THE INITIAL INTENSITY HAS DECREASED TO 100 KNOTS. EARL
SHOULD CONTINUE TO WEAKEN GRADUALLY AS THE SHEAR INCREASES AND THE
HURRICANE SHOULD WEAKEN EVEN FASTER AFTER 24 HOURS AS IT MOVES OVER
A COLDER OCEAN.  AFTER CROSSING CANADA IN 48 HOURS…EARL SHOULD
BECOME POST-TROPICAL/EXTRATROPICAL AND THEN DISSIPATE AS IT IS
ABSORBED BY A MUCH LARGER EXTRATROPICAL CYCLONE.

SATELLITE AND RECONNAISSANCE FIXES SHOW…AS ANTICIPATED…THAT EARL
HAS TURNED NORTHWARD AND IS MOVING 360 DEGREES AT 16 KNOTS. THE
STEERING PATTERN CONTROLLING THE MOTION OF EARL…AND THE
CONSISTENCY IN TRACK GUIDANCE…HAVE BEEN ADEQUATELY DESCRIBED IN
PREVIOUS DISCUSSIONS. EARL IS ABOUT TO BECOME EMBEDDED IN THE
MID-LATITUDE FLOW AND IT IS READY TO GRADUALLY TURN TO THE
NORTH-NORTHEAST AND NORTHEAST WITH AN INCREASE IN FORWARD SPEED.

ALTHOUGH THE MAXIMUM WINDS IN THE CORE HAVE DECREASED…EARL
CONTINUES TO BE A LARGE AND POWERFUL HURRICANE.

FORECAST POSITIONS AND MAX WINDS

INITIAL      02/2100Z 32.5N  75.2W   100 KT
12HR VT     03/0600Z 34.8N  74.8W    95 KT
24HR VT     03/1800Z 38.0N  72.7W    85 KT
36HR VT     04/0600Z 41.7N  69.0W    75 KT
48HR VT     04/1800Z 46.5N  64.5W    50 KT…POST-TROP/EXTRATROP
72HR VT     05/1800Z…DISSIPATED

$$
FORECASTER AVILA

Hurricane Earl Eyes US: Hurricane Warning Flags Flying on East Coast September 1, 2010

Hurricane Earl 1915Z IR Rainbow Image 09.01.10-Click Image for Real time Loop

Click Here For The Most Recent Update Regarding Hurricane Earl’s Brush with the US East Coast

Hurricane Earl 1915Z Visible Satellite Image 09.01.10-Click Image for Real Time Loop

If you recall, yesterday I mentioned that one aspect of the forecast regarding Hurricane Earl was the dry air in which Earl was moving into.  I had thought that perhaps dry air might work its way into the circulation of the hurricane and perhaps limit its intensity potential or even bring it down a notch or two.  At 5 AM on Wednesday September 1, 2010 the National Hurricane Center included this bit of information near the end of it’s discussion: ” …WATER VAPOR IMAGERY SHOWS A TONGUE OF MID/UPPER-LEVEL DRY AIR WRAPPED MORE THAN HALFWAY AROUND THE CYCLONE.”  I honestly had been surprised that they had not mentioned that potential earlier because the the scale of the dry air ahead of the storm was rather large.   Nevertheless, by Wednesday afternoon, the outflow symmetry of Earl looks to have improved  and the dry air looks to have been absorbed without a whole lot of disruption; perhaps it hurt Earl a bit.  But, Earl overcame the dry air and at 5pm EDT on Wed Sept 1 had maximum winds of 135 mph with gusts to 160 mph.  Central pressure was 941mb and was moving at 310 -320 degrees (NW) at 17 mph.    The dry air was one of the “challenges” that I referred to that I felt Earl would face in maintaining its intensity.  There are other issues at play as well that suggest the storm has seen its better days and its ferocity will not be as great as it once was, or even feared it would be, when it affects the US Coast.  Nevertheless, I would not take the storm lightly and it would be advisable to get out of its way if you may be in the path of Earl.

N. Atlantic Basin Total Precipitable Water Image-Click For Loop That Clearly Indentifies Cyclone in the N. Atlantic

18Z Hurricane Earl Spaghetti Model Track 09.01.10-Note Model track or two suggest a mainland landfall

As of 5 PM EDT Wednesday, Hurricane Warning flags have been hoisted from  Bouge Inlet, North Carolina to the North Carolina/Virginia.  A Hurricane Watch extends from the North Carolina/Virginia border to Cape Henlopen, DE and from Woods Hole, MA to Sagamore Beach, MA.  Tropical Storm Warnings are posted from the North Carolina/Virginia border to Sandy Hook, NJ.  A Tropical Storm Warning means tropical storm conditions are likely within 36 hours, A Hurricane Watch and a Tropical Storm Watch means that those conditions are possible within 48 hours.  A Hurricane Warning means that hurricane conditions are expected in the warned area with the onset of tropical storm force winds expected within 36 hours.  Tropical Storm winds are considered to be 40 to 73 mph and winds are considered hurricane force at 74 mph.  Remember, these are sustained winds, not gusts.  Winds can gust to at least 20% higher than the sustained winds.  It is not uncommon with a hurricane for a region to experience continuous hurricane force winds for many hours.  Most people who survive “riding out” a hurricane swear they will never do so again.  Wind is only part of the story as torrential rain is always a part of a hurricane and the storm surge associated with any hurricane is typically the gravest life taker.  People generally have no idea just how powerful the sea can be.  Click here for to find the storm surge probability forecast for your region.

Note the Trof in N. Central US on 1845Z Atlantic IR Rainbow Image 09.01.10-Click Image for Real Time Loop

18Z Hurricane Earl Spaghetti Model Intensity Graph 09.01.10

By midday on Wednesday,  Hurricane Earl had continued its gradual curvature around a big fat ridge extending from the Atlantic.  As the ridge continues to move eastward,  Earl will continue its right hand shifting and will eventually be moving due North.  By late Thursday, the long anticipated trof moving across the northern United States will be close enough to pick up Earl.  The result will be an increase in forward speed as well as a turning of the storm; first North-Northeast and eventually Northeast.  The timing of the trof will be the determining factor as to the precise track of Earl up the East Coast, particularly off of New England.  The variable is so slight that no one can say with certainty how it will play out.  An hour or so timing difference of the trof’s influence on Earl can make the difference between the storm staying offshore or running over land.  Suffice it to say, it will be at least a close call and no one along the NE Coast of the United States will escape some affect of Hurricane Earl. 

Atlantic Sea Surface Temperatures-Click for Loop

While the shearing winds from the Southwest ahead of the trof and the dry air trying to work its way into Earl may serve to limit its intensity,  forecasts continue to call for a major hurricane with winds of 100 to 120 mph running just off the North Carolina, Virginia, Maryland and Delaware coasts.  By the time its off the New England coast, it will be probably scooting along at least at 30 mph and winds will have diminished from weakening due to the shearing winds that mess up its upper support as well as colder water. Tropical Cyclones need surface water temperatures of at least 80 F current coastal conditions from off of Delware northward fall below that level.  Farther out though, in the Gulf Stream, waters remain above 80 F extend a shade farther north.   However, hurricane conditions may still be probable for Long Island and Cape Cod, if not the mainland of the New England states.  The official track keeps the storm offshore but it would not take much of a deviation, say 20 miles, for the eye of the hurricane to run right over Long Island and perhaps Cape Cod or Nantuckett Island.  While its not entirely likely, it is not totally out of the question for Earl to actually make at least a partial landfall on some portion of the mainland. 

NHC Hurricane Earl Forecast Track 5PM EDT 09.01.10

While the winds may back off as it heads farther North, the increase in forward speed may serve to enhance the storm surge to the right of the storm.  Further, given that Earl was a big bopper, the sea will not necessarily react as quickly to diminishing winds so the surge may be on the top end of the normally expected storm surge associated with a minimal hurricane running up the East coast.  So, when you hear the forecasts call for a category 1 hurricane off the Jersey shore of off of the New England coast, it would be advisable not to pooh-pooh it as the destructive potential of a  category 1 hurricane can be somewhat excessive. 

18Z Tropical Depression 9 Spaghetti Model Track 09.01.10

Behind this is Tropical Storm Fiona which has been experiencing some difficulty as the outflow from Earl has been disrupting its outflow.  Aside from its intensity, the same trof that is picking up Earl will most likely pick up Fiona as well, regardless of its strength, and should turn it north well before it threatens the US coast.  Behind Fiona is a Tropical Wave (Invest 98) and Tropical Depression 9 which was designated at Tropical Storm Gaston at 5pm EDT September 1.  Invest 98 appears to be running over the same worked-over water as Danielle, Earl and Fiona and may have a difficult time developing.  However, Tropical Storm Gaston is farther south and the initial modeling data suggests its track will be more westerly and as it will be far enough south as to not be influenced by any trofs farther North.  While there is no data currently showing a rapid intensification, a few models do indicate that it will develop into a hurricane and the general track would suggest the potential exists for it to some day affect the US coast from the Gulf of Mexico to the East Coast.  It’s a long way out and there are many scenarios so there will be time to monitor its development. 

HURRICANE EARL DISCUSSION NUMBER  30
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072010
500 PM EDT WED SEP 01 2010

VISIBLE SATELLITE IMAGES INDICATE THAT THE EYE HAS BECOME VERY
DISTINCT…WITH OJECTIVE T-NUMBERS OSCILLATING AROUND 6.0 FOR THE
PAST FEW HOURS. AN AIR FORCE PLANE MEASURED FLIGHT-LEVEL WINDS OF
138 KNOTS AND A MINIMUM PRESSURE OF 941 MB IN THE LAST FIX.
HOWEVER…SFMR MEASUREMENTS WERE A LITTLE LOWER. A COMPROMISE OF
THESE DATA SUPPORTS AN INITIAL INTENSITY OF 115 KNOTS.
HOWEVER…EARL COULD FLUCTUATE IN INTENSITY DURING THE NEXT 12 TO
24 HOURS BUT SHOULD BEGIN TO GRADUALLY WEAKEN AS IT REACHES
COOLER WATERS AND MOVES INTO HIGHER SHEAR BEYOND 36 HOURS. BY DAY 5
THE HURRICANE SHOULD HAVE BEEN ABSORBED BY A LARGE EXTRATROPICAL
CYCLONE WELL NORTH OF CANADA.

SATELLITE AND RECONNAISSANCE AIRCRAFT FIXES INDICATE THAT EARL
HAS BEEN MOVING RELENTLESSLY TOWARD THE NORTHWEST OR 310 DEGREES
AT 15 KNOTS. THE HURRICANE IS ABOUT TO REACH THE WESTERN EDGE OF
THE SUBTROPICAL RIDGE AND SHOULD BEGIN TO TURN MORE TO THE
NORTH-NORTHWEST AND NORTH LATER TONIGHT AND THURSDAY. IN ABOUT 36
HOURS OR SO…THE HURRICANE WILL ENCOUNTER THE BASE OF THE
MID-LATITUDE WESTERLIES AND SHOULD BEGIN TO RECURVE OR TURN TO THE
NORTHEAST WITH AN INCREASING FORWARD SPEED. THIS IS THE SOLUTION
CONSISTENTLY PROVIDED BY TRACK MODELS…WHICH HAVE EARL PASSING TO
THE EAST BUT NOT FAR FROM THE OUTER BANKS OF NORTH CAROLINA ON
THURSDAY NIGHT. ONLY A SMALL WESTWARD DEVIATION OF THE TRACK TO THE
WEST WOULD BRING THE CORE OF THE HURRICANE TO THE COAST.

GIVEN THE FORECAST TRACK…THE LARGE SIZE OF THE WIND FIELD…AND
THE EXPECTED INCREASE IN FORWARD SPEED WATCHES AND WATCHES HAVE
BEEN EXTENDED NORTHWARD ALONG THE EAST COAST OF THE UNITED STATES.

FORECAST POSITIONS AND MAX WINDS

INITIAL      01/2100Z 26.3N  73.3W   115 KT
12HR VT     02/0600Z 28.4N  74.7W   115 KT
24HR VT     02/1800Z 31.7N  75.4W   110 KT
36HR VT     03/0600Z 35.1N  74.7W   100 KT
48HR VT     03/1800Z 38.5N  72.2W    90 KT
72HR VT     04/1800Z 46.5N  63.5W    60 KT
96HR VT     05/1800Z 58.0N  57.0W    40 KT…POST-TROP/EXTRATROP
120HR VT     06/1800Z…DISSIPATED

$$
FORECASTER AVILA

Hurricane Bill Losing Tropical Characteristics But Still Flogging Halifax, Nova Scotia August 23, 2009

Hurricane Bill Sunday 9:15:15 Z

Hurricane Bill NHC forecast track 11AM Sun 08.23.09

for a the final “Bill” discussion and cool photos and video of waves and other stuff from Hurricane Bill, CLICK HERE!

When I last posted on Bill, in my mind, it appeared that the beginnings of the end of Bill as a tropical system had begun.  The National Hurricane Center reports this morning that indeed, the transformation of Bill from tropical system into an extra-tropical cyclone is far enough along that they feel as if the winds aloft are no longer able to be efficiently brought down to the surface.  I think that’s an understatement based on the satellite image.  It doesn’t look like a tropical cyclone but instead an extra-tropical system.  Also, I had mentioned in the prior post abou that prospects of dry air getting into the middle.  The Water Vapor imagery clearly indicates that has indeed happened.  I had thought the storm would have picked up forward speed to about 40 mph by now but it is only up to 35 mph.  I wouldn’t be surprised to see it moving at closer to 50 mph before it gets to Scotland.  It would appear that the official forecast has discounted my complete speculation that there may be an opportunity for this to curve around the ridge back to Spain.  Apparently, the ridge extends back into Europe so that ain’t gonna happen. Nevertheless, I see that a couple of models on the spaghetti model graphic do indicate a curve back to Spain, so there is hope that I will be vindicated! 

Iceberg Resistant Hibernia Remains in Operation

At 9:50pm EDT there a buoy located 30 NM east of Nantucket reported winds of 21 kts gusting to 27 kts with 19 foot seas. Another 54nm SE of Nantucket had winds of 27 kts gusting to 38 kts with seas over 27 feet.   An interesting observation came at 12pm ADT from a Canadian buoy at the mouth of Halfax Harbour.  It indicated that the pressure was down .38″ in the past 3 hours and was falling rapidly.  That tells you that the center of the storm was still approaching. The pressure was at 29.28″   Winds were 29 kts gusting to 35 kts and the wave height was 14.4 feet.  A little farther out and to the Southeast, Buoy 44150 is located at 42.5 N and  64.02 W and had a steady pressure tendency at 29.12″.  This tells me that the center of the storm is there.  Winds at 12 ADT were 52 kts with gusts to nearly 70 kts.  Seas were running at nearly 40 feet.  So, it would appear from limited reports from a few buoys that Bill has minimal hurricane status winds but is kicking up some pretty big ocean swells.  A morning news report brought an interesting story that the giant Hibernia offshore platform would be operating normally.  Typically, when a storm passes through an oil field, the crews of production and drilling platforms are evacuated and operations are shut down.  That can be expensive but it lessens the risk for life and also the risk of an oil spill.  They evacuated Sable, which is a gas production platform…but the 98,200 barrel a day oil production Hibernia remains in operation.  That is rather remarkable.

Hurricane Bill Spaghetti Model 12Z 08.23.09

Hurricane Bill Spaghetti Intensity Model 12Z Sun

Bill Water Vapor 9:16:15Z 08.23.09

WTNT43 KNHC 231448
TCDAT3
HURRICANE BILL DISCUSSION NUMBER  33
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL032009
1100 AM AST SUN AUG 23 2009

AFTER THE LAST AIR FORCE MISSION INTO BILL….JUST BEFORE 1200
UTC…THE CLOUD PATTERN OF THE HURRICANE HAS BEGUN TO LOOK A LITTLE
LESS TROPICAL.  THE AIRCRAFT REPORTED A PEAK FLIGHT-LEVEL WIND OF
105 KT OVER THE EASTERN QUADRANT AROUND 1100 UTC.  TYPICALLY THIS
WOULD SUPPORT A HIGHER INTENSITY OF GREATER THAN 75 KT.
HOWEVER…SINCE THE CYCLONE IS TRAVERSING COOLER WATERS…IT IS
BECOMING INCREASINGLY DIFFICULT FOR IT TO TRANSPORT STRONG WINDS

Bill Visible Satellite 09:16:15Z 08.23.09

TO
THE SURFACE.  GIVEN THAT…ALONG WITH THE DETERIORATION OF THE
CLOUD PATTERN…THE CURRENT INTENSITY IS HELD AT 75 KT.  BILL IS
EXPECTED TO BECOME AN EXTRATROPICAL STORM WITHIN A DAY OR SO AND
GRADUALLY WEAKEN AS IT MOVES RAPIDLY ACROSS THE NORTH ATLANTIC.
GLOBAL MODELS SUGGEST THAT THE SYSTEM WILL MERGE WITH A BROADER
CYCLONIC CIRCULATION NEAR THE BRITISH ISLES IN 3-4 DAYS.

CURRENT MOTION IS AROUND 045/29.  BILL SHOULD CONTINUE ACCELERATING
OVER THE NEXT 24-36 HOURS AS IT BECOMES WELL EMBEDDED IN THE
MID-LATITUDE WESTERLIES.  SOME SLOWING OF THE FORWARD SPEED IS
LIKELY LATER IN THE PERIOD AS THE EXTRATROPICAL REMNANT OF BILL
INTERACTS WITH THE LARGE CYCLONIC CIRCULATION OVER THE NORTHEAST

Sea Surface Temperatures (SST) 08.22.09 12Z

ATLANTIC.  THE CURRENT OFFICIAL TRACK FORECAST IS SIMILAR TO THE
PREVIOUS ONE.

LARGE AND DANGEROUS SWELLS ASSOCIATED WITH BILL WILL BE IMPACTING
THE CANADIAN MARITIMES DURING THE NEXT 24 HOURS.  SWELLS ALONG THE
EAST COAST OF THE UNITED STATES SHOULD BE DIMINISHING TODAY.

FORECAST POSITIONS AND MAX WINDS

INITIAL      23/1500Z 43.3N  64.0W    75 KT
12HR VT     24/0000Z 46.3N  59.1W    65 KT
24HR VT     24/1200Z 49.0N  49.7W    55 KT…EXTRATROPICAL
36HR VT     25/0000Z 50.8N  37.4W    45 KT…EXTRATROPICAL
48HR VT     25/1200Z 52.5N  26.5W    35 KT…EXTRATROPICAL
72HR VT     26/1200Z 57.0N   8.0W    30 KT…EXTRATROPICAL
96HR VT     27/1200Z…MERGED WITH ANOTHER LOW

$$
FORECASTER PASCH

Pink Sand From Hurricane Bill; Spaghetti Models Better Days Have Passed August 22, 2009

Hurricane Bill 1415Z Aug 22

For a more recent update on Hurricane Bill, CLICK HERE

Hurricane Bill passed by Bermuda and forced President and Secretary of State Clinton to end their Bermuda vacation early.  Bill was chased away by Bill.   Hurricane Bill tossed pink sand on the beaches of Bermuda. 

NHC official Hurricane Bill Fcst Track 8am Aug 22Hurricane Bill Spaghetti Model 12Z 08.22.09

Bill Spaghetti Model Intensity 12Z 08.22.09

Hurricane Bill Water Vapor Image 1415Z 08.22.09

I gotta say that Bill was looking pretty ragged late Friday.  The circulation and outflow had been displaced somewhat to the north and northeast for several days in response to light southwesterly winds.  But as they increased, it was even more non-circular on Friday.   It was going through an eyewall replacement cycle and the conventional wisdom was that it might be able to ramp up some today in one last hurrah before it went to die.  Well, there is no evidence of that, though the satellite image in some regards looks better than it did…more circular..but there is no eye.  I almost looks like its trying  lose its tropical characteristics already.  So, I would be of the mind that it has seen its better days and is in the beginning stages of losing its tropical characteristics and getting really messed up.  From this point forth, the shearing winds will do nothing but  increase and the water temperatures will do nothing but decrease.  

Hurricane Bill Visible Satellite Image 1415Z 08.22.09

In looking at the water vapor imagery, you see very dry air to the south of Bill and I wonder if that dry air doesn’t end up getting drawn into the storm, which would serve as a pitchfork if it got into the center.  The official track does not advertise a landfall, instead having it move more or less parallel to the Canadian Maritime coast.  But, if I were in Halifax or really anywhere on coastal Nova Scotia, I would evacuate.  The storm surge will still be significant.  Two interesting things are that it will be moving very fast so I could create a scenario in which the water rises very rapidly prior to the storm passing south of the coast and then it rushing out quickly as it passes with the backside winds shoving the water back out to sea.  The other is its ultimate fate.  The general storm track takes it toward Scotland, which would be interesting in itself.  But, if that ridge in the Atlantic is not established that far east, I”m wondering if it might not move more southeast eventually and go toward Spain and Portugal.  Speculation, but  interesting nonetheless.

Sea Surface Temps (SST) 12Z 08.21.09

WTNT43 KNHC 221442
TCDAT3
HURRICANE BILL DISCUSSION NUMBER  29
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL032009
1100 AM AST SAT AUG 22 2009

SATELLITE IMAGES INDICATE THAT BILL HAS NOT BECOME ANY BETTER
ORGANIZED AND THE T-NUMBERS HAVE CONTINUED TO DECREASE. INITIAL
INTENSITY HAS BEEN ADJUSTED DOWN TO 85 KNOTS AND THIS VALUE COULD
BE GENEROUS. AN AIR FORCE PLANE WILL CHECK BILL THIS AFTERNOON AND
WILL GIVE US A BETTER ESTIMATE OF THE INTENSITY AND WIND RADII. BILL
IS EXPECTED TO MAINTAIN ITS STRENGTH TODAY BUT WITH COLD WATERS
AHEAD…A GRADUAL WEAKENING SHOULD BEGIN TONIGHT. IN ABOUT 48
HOURS…THE EXTRATROPICAL TRANSITION SHOULD BEGIN AND BY 72 HOURS
BILL SHOULD BE FULLY EXTRATROPICAL.

THERE HAS BEEN NO SIGNIFICANT CHANGE IN TRACK. BILL IS MOVING
TOWARD THE NORTH OR 355 DEGREES ABOUT 20 KNOTS. THE HURRICANE IS
ALREADY EMBEDDED WITHIN THE FLOW BETWEEN THE AZORES-BERMUDA HIGH
AND A MID-LATITUDE TROUGH OVER THE EASTERN UNITED STATES. THIS
PATTERN SHOULD FORCE BILL TO RECURVE WITH A GRADUAL INCREASE IN
FORWARD SPEED. THE OFFICIAL FORECAST IS IN THE MIDDLE OF THE
GUIDANCE ENVELOPE AND BECAUSE THE GUIDANCE CONTINUES TO BE TIGHTLY
PACKED…THERE IS HIGH CONFIDENCE IN THE TRACK FORECAST. THE
FORECAST TRACK BRINGS BILL TO THE WATERS JUST SOUTH OF NOVA SCOTIA
IN 24 HOURS. THEREFORE…ENVIRONMENT CANADA HAS ISSUED WATCHES AND
WARNINGS FOR EASTERN REGIONS OF CANADA.

LARGE SWELLS GENERATED BY BILL ARE ARRIVING ALONG THE EAST COAST OF
THE UNITED STATES. THESE SWELLS WILL SPREAD NORTHWARD OVER THE
WEEKEND…CAUSING EXTREMELY DANGEROUS SURF AND LIFE-THREATENING RIP
CURRENTS. PLEASE CONSULT STATEMENTS ISSUED BY YOUR LOCAL WEATHER
OFFICE AND METEOROLOGICAL SERVICES FOR MORE DETAILS.

FORECAST POSITIONS AND MAX WINDS

INITIAL      22/1500Z 35.1N  68.6W    85 KT
12HR VT     23/0000Z 38.0N  68.5W    85 KT
24HR VT     23/1200Z 42.5N  65.5W    75 KT
36HR VT     24/0000Z 46.0N  59.0W    65 KT
48HR VT     24/1200Z 49.5N  49.4W    50 KT…BECOMING EXTRATROPICAL
72HR VT     25/1200Z 52.0N  24.0W    40 KT…EXTRATROPICAL
96HR VT     26/1200Z 58.0N   9.0W    30 KT…EXTRATROPICAL
120HR VT     27/1200Z 63.0N   5.0W    20 KT…EXTRATROPICAL

$$
FORECASTER AVILA

Hurricane Bill Spaghetti Models Indicate It Will Be Reluctant to Die August 21, 2009

Notice Sea Surface Temps Off NE US Coast Are Colder 12Z Aug 21

Bill Visible Satellite 2215Z Aug 21...Small Eye

For a more recent update on Hurricane Bill, CLICK HERE

 Hurricane Bill is providing a pretty good lesson on how hurricanes work and forecasting.  If you look at the National Hurricane Center Hurricane Bill Discussion, they note that the winds have decreased and that the pressure was up a bit to 954 mb.  Also, the satellite imagery makes it hard to find the eye.  The Hurricane Hunter Aircraft reports an eye of 14 miles.  If you recall, earlier it had been running about 35 miles and was clearly visible on the satellite images.  One thing that the discussion does not say is that the vortex message indicates that the eye is open in the Southwest quadrant.  On the surface, this all appears to mean that Bill is dying.  In a sense, it is because it is headed toward colder water and a more hostile environment….but not just yet.  Again, in the discussion it talks about a second wind maxima.  What appears to be going on is that Bill is going through another eyewall replacement cycle.  Most likely, the open part of the eye

2215z Aug 21 Bill Infared rainbow Satellite

is indicative of a deteriorating inner eye all and the second maxima is indicating that a new eye is forming.  The smaller eye is probably a result of the old eye collapsing in.  The pressure rise was not all that dramatic and fairly typical of a storm going through a replacement cycle.  The idea here is that as the storm bends on Saturday from its Friday evening 340 degree vector to a 360 degree heading, it will still be in a relatively weak shearing environment and be over warm water.  It will have completed the eyewall replacement cycle and so it should ramp up a bit in intensity.  This eyewall replacement process is why it is really tough for a mature hurricane to maintain a maximum intensity for a long period. For that reason, it is rare for a category 5 hurricane to make landfall in the United States.  I think its only happened 3 times..Camille in 1969, Andrew in 1992 and a Florida hurricane in the 1920s or 1930s…maybe the Keys Hurricane.  The timing just has to be right..or wrong as the case may be. 

2215z aug 21 Bill Water Vapor Shows some trouble

Anyway, Bill’s uptick will probably not be back up to category 4 status and whatever increase in intensity will not last long.  The big long wave trof has made its way across the Ohio Valley and weekend temperatures will be in the 70′s over much of the region.  It’s a fall like pattern and Bill is behaving like a fall-like storm.  As Bill moves north….probably about the time its even with Washington DC, it will start to encounter strong southwesterly winds ahead of the trof and that will start to rip it up.  It will also be running into cold water and as it approaches Nova Scotia, Bill will start to take on a northeastward component and its forward speed  will increase rapidly and markedly. It will lose its tropical characteristics and probably be in Scotland by the middle of next week.  But, even though it may parallel the coast of Nova Scotia and be losing its tropical characteristics, the pressure gradient between it and the big ridge in the Atlantic will still be large and therefore strong winds, perhaps still running about 100 mph will be pushing water on the right hand side of the storm up in the form of a storm surge.  Harbors, bays and inlets in Nova Scotia and other land masses will have a pretty rapid and significant sea rise.  What’s interesting is that with the storm moving so fast, if it does parallel the coast, then they may see a rapid retreat of extreme tidal surges as the wind shifts around from the north on the back side.    If I’m in Halifax or anywhere in Nova Scotia, I’m still heeding the local warnings and advisories.

Hurricane Bill Spaghetti Model 08.21.09

Hurricane Bill Spaghetti Intensity Model 18Z Aug 21

NHC Official Bill Forecast Track Aug 21 5pm

WTNT43 KNHC 212040
TCDAT3
HURRICANE BILL DISCUSSION NUMBER  26
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL032009
500 PM AST FRI AUG 21 2009

AN AIR FORCE HURRICANE HUNTER AIRCRAFT REACHED BILL THIS
AFTERNOON AND FOUND THAT THE CENTRAL PRESSURE HAS REMAINED AROUND
954 MB…BUT THE WINDS HAVE DECREASED AND INITIAL INTENSITY IS NOW
90 KT. THE PLANE REPORTED A SMALL EYE OF 14 N MI DIAMETER.
GIVEN THE CONCENTRIC RING STRUCTURE OBSERVED ON MICROWAVE AND THE
DOUBLE WIND MAXIMA PROVIDED BY THE PLANE…IT IS LIKELY THAT THE
HURRICANE IS GOING THROUGH AN EYEWALL REPLACEMENT AND THE REASON
FOR THE CURRENT WEAKENING. THERE IS AN OPPORTUNITY FOR BILL TO
REGAIN SOME STRENGTH DURING THE NEXT 12 TO 24 HOURS WHILE THE SHEAR
IS LOW AND BEFORE THE HURRICANE REACHES COOLER WATERS.
THEREAFTER…A STEADY WEAKENING IS INDICATED AND BY 72 HOURS…BILL
SHOULD ALREADY BE AN EXTRATROPICAL CYCLONE INTERACTING WITH THE
HIGH LATITUDE WESTERLIES.

BILL IS NOW MOVING TOWARD THE NORTH-NORTHWEST OR 340 DEGREES AT 17
KNOTS. THE HURRICANE SHOULD GRADUALLY TURN MORE TO THE NORTH AROUND
THE BERMUDA-AZORES HIGH TONIGHT AND SATURDAY AND SHOULD BE FORCED TO
RECURVE AS A LARGE MID-LATITUDE TROUGH MOVES EASTWARD ACROSS THE
EASTERN UNITED STATES.  THERE HAS NOT BEEN ANY CHANGE IN TRACK
GUIDANCE WHICH IN FACT CONTINUES TO BE TIGHTLY PACKED…MAINTAINING
HIGH CONFIDENCE IN THE TRACK FORECAST.

LARGE SWELLS GENERATED BY THIS HURRICANE WILL AFFECT A LARGE PORTION
OF THE WESTERN NORTH ATLANTIC COASTAL AREA DURING THE NEXT FEW
DAYS.  THESE SWELLS WILL LIKELY CAUSE EXTREMELY DANGEROUS SURF AND
LIFE-THREATENING RIP CURRENTS.  PLEASE CONSULT STATEMENTS ISSUED BY
YOUR LOCAL WEATHER OFFICE AND METEOROLOGICAL SERVICES FOR MORE
DETAILS.

AT THIS TIME…TROPICAL-STORM-FORCE WINDS ARE NOT FORECAST TO REACH
NEW ENGLAND.  HOWEVER…A SLIGHT SHIFT OF THE FORECAST TRACK TO THE
LEFT WOULD REQUIRE A TROPICAL STORM WATCH OR WARNING TONIGHT.  THE
WIND SPEED PROBABILITY PRODUCT INDICATES THAT THERE IS ROUGHLY A 25
PERCENT CHANCE OF THESE WINDS REACHING EXTREME SOUTHEASTERN NEW
ENGLAND.

FORECAST POSITIONS AND MAX WINDS

INITIAL      21/2100Z 29.4N  66.9W    90 KT
12HR VT     22/0600Z 31.7N  68.0W   100 KT
24HR VT     22/1800Z 35.1N  68.4W   100 KT
36HR VT     23/0600Z 39.0N  67.2W    85 KT
48HR VT     23/1800Z 43.0N  64.0W    75 KT
72HR VT     24/1800Z 49.5N  47.0W    50 KT…EXTRATROPICAL
96HR VT     25/1800Z 54.5N  20.0W    45 KT…EXTRATROPICAL
120HR VT     26/1800Z 60.0N   6.0W    35 KT…EXTRATROPICAL

$$
FORECASTER AVILA

Iraq Gains Independence, November Gets a Holiday and a Hurricane Season Forecast October 3, 2008

Sea Surface Temperatures Oct 2, 2008

No change in the forecast which means no rain but pretty good weather. Our cooldown, as previously indicated, will not be long lasting. As I had suggested several days ago, I was not surprised to see outlying areas in the upper 30′s to near 40 on Wednesday night. I was a bit surprised at temperatures near freezing in low lying lake areas, though. Thursday night, look for something similar and then we go into a warming phase. Mid 70′s Fri, Upper 70′s Sat, Low 80′s Sun, mid 80′s much of the week ahead.

2008 Hurricane Forecast-Revised Aug

2008 Hurricane Season: Hurricane season ends November 30 and began June 1. Those great prognosticators of hurricanes had suggested a season of well above average numbers of storms. In May the government forecast was for 12-16 storms and then in August, they bumped it up to 14-18 storms with 7-10 hurricanes and 3-6 major hurricanes. All I can say is that the currently quiet North Atlantic better hurry up. So far, there have been 12 named storms. Laura was a “sub-tropical” storm and then was a tropical storm for a cameo appearance and then it went away. But, it still counts. Six of the 12 have been classified as a hurricane with Ike and Gustav as major storms. For the record, there is an average of 11 named storms with six becoming hurricanes and 2 becoming major hurricanes. A major hurricane is a cat 3 or higher. There is nothing out there on the horizon except for an area of disturbed weather in the western Caribbean. However, sea surface temperatures are plenty warm enough to support tropical cyclone activity from Africa all the way to the Texas coast.

CLICK HERE for a very interesting loop of Hurricane Ike. It is a series of graphics showing the windfield as it moved across the Atlantic and the Gulf of Mexico and inland through Texas. You can see the way the windfield expanded as it went into the Gulf. From this link, you will have access to other loops.

for a whole mess of photos and video relating to hurricane ike, CLICK HERE and scroll through the September 2008 archive.

Not the 1st Thanksgiving?

On This Date In History: We’ve all enjoyed Thanksgiving Dinner and we all probably learned in grade school that the first Thanksgiving involved the Pilgirms and the native Indians of North America. But, the real first official Thanksgiving Holiday was proclaimed on this date in 1863 by President Lincoln, calling for an annual day of national Thanksgiving on the fourth Thursday of November. The president used the opportunity to thank the Union Army for the reversal of fortune in the Union effort by the victory at Gettysburg. President Washington had declared a “national day of thanksgiving and prayer” in 1789, but it didn’t become an annual event. In fact, Thomas Jefferson thought that such national events of demonstration towards a deity was not appropriate. Other presidents agreed until President Lincoln’s decree. President Franklin Roosevelt tried what I call a political move in 1939 when he moved the holiday to the third Thursday. However, I suppose its plausible to argue that Lincoln’s initial declaration was rooted in politics. Anyway, FDR was hoping to extend the Christmas shopping season. I guess he thought that by moving Thanksgiving he could pull the wool over American’s eyes and use the psychology of calling a different day Thanksgiving to get them to spend more money. Anyway, Congress had enough of the foolishness and in 1941 put the national holiday back to where President Lincoln put it in the first place.

A book on the Subject

On This Date in 1932 Iraq gained independence. The region had been ruled by the Ottoman Empire, which dissolved at the conclusion of World War I. Britain occupied the area and was given a League of Nations mandate to govern the region in 1920. They set up a monarchy and granted independence in 1932. That government maintained strong military and economic ties with Britain and that resulted in numerous protests. In 1941, a pro-Axis (Germany, Italy, Japan) movement took hold and the UK intervened causing the Iraqi government to agree to back the good guys in the war. The monarchy got over thrown in 1958 and for the next 20 years, Iraq was ruled by a series of civilian and military governments until Saddam Hussein became dictator in 1979….a position he held until 2003. Saddam has since left to try to rule another world. However, from its 20th century history, its easy to see why there are skeptics that a democracy can flourish in the region. But, the global political situation is not as it was nor is the politics of the region so one cannot use history as a prescription for the future.