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 Earl Faces Challenges, Still Major Threat to US East Coast August 31, 2010

Hurricane Earl Visible Satellite 1945Z 08.31.10 In Midst of Eyewall Replacement Cycle; Dry Air May Be Trying to Work In-Click Image for Real Time Loop

Note Great Lakes Trof and Huge Area of Dry Air Over Mid Atlantic States: Click Image for Real Time North Atlantic IR Rainbow Loop

CLICK HERE FOR MORE RECENT UPDATE CONCERNING HURRICANE EARL, HURRICANE WARNINGS AND WATCHES ALONG THE US EAST COAST AS FAR NORTH AS MASSACHUSETTS

Hurricane Earl has been behaving like a well developed hurricane as during the day on Tuesday it has been going through an eyewall replacement cycle.   Typically, the old eyewall collapses and a new eyewall forms.  During this time, any given storm’s maximum winds will typically decrease in response to a rise in the central pressure.  However, the energy tends to get dispersed throughout the storm, thus winds in the extremities may be higher than normally expected as the gradient is not quite as steep.  This is what happened with Hurricane Katrina:  it was going through an eyewall replacement cycle when it made landfall and so it was only a category 3 hurricane but, winds in excess of 100 mph were experienced well away from the center.  I believe that the winds were about 125 mph at the point of landfall in Western Mississippi but winds of 108 mph were felt near Mobile Alabama.  In any event, Earl should complete this cycle by Tuesday afternoon and thereafter some moderate strengthing is possible, though most models do not take it to category 5 status.    So, it may max out at around 140 mph and not 155.  What’s 15 mph amongst friends?  It’s still an extremely formidable storm.

NAM 850mb 12Z Thu 09.02.10 Note Movement of Trof East

NAM 12Z 850mb Wed 09.01.10 Note Trof Over Great Lakes

We had a big high pressure ridge over the Eastern United States last week and another ridge in the Atlantic with a trof in between.  Hurricane Danielle followed the trof that split the two ridges and stayed well out in the open waters of the Atlantic.  By this weekend, that weakness between the two ridges filled in and formed generally one large ridge from the mid Atlantic to the Eastern US with a slight weakness in the ridge along the US East Coast.  Now, as hurricanes traverse farther north from the equator, the coriolis parameters become greater.  The coriolis force is the apparent motion caused by the rotation of the earth.  Any hurricane in the Northern Hemisphere will want to move to the right due to the rotation of the earth.  Until the last day or so, the ridge to the north was strong enough to for the most part overcome the coriolis parameters and keep Earl moving generally westward.  However, as Earl moved north of the Virgin Islands, it began to get toward the edge of the strongest part of the ridge and now is moving to the right of a westward track.  Midday Monday it had a vector of 285 degrees and by the evening it was running at 300 degrees.  This however is not the expected turn north.

NAM 12Z Fri 850mb 09.03.10 Note Relation of Trof on East Coast Vs. Earl Position

That turn north will not occur until a trof moving across the northern part of the United States moves eastward to the US East Coast.  When it does, it will provide the channel for Earl to turn north and run up the trof.  A c0uple of things will happen at that time.  The southwesterly flow ahead of the trof will pick up the storm and turn it north and then eventually north-northeast and then northeast and the forward speed of Earl will also increase.  By the time its up to about 35 degrees North Latitude, it will most likely be scooting along at about 30 mph.  That southwesterly flow will not only turn it and increase its forward speed, it should also disrupt the outflow aloft and that would tend to limit any intensification potential or even lead to a decrease in intensity.  Even though there is a high probability of that coming about, it will still be a very strong storm with a high storm surge potential and its even possible that the forward speed might enhance the surge potential in the front right quadrant. 

1845Z Water Vapor-Huge Area of Dry Air Looks As if it is trying to wrap into Earl: Click Image for Real Time Loop

With regard to the intensity there is another potential fly in the ointment that could prove beneficial.  I noticed yesterday a huge area of dry air on the water vapor imagery to the north of Earl.  That dry air is not quite as large in scale today but it’s still there and is moving south.  Earl will be moving right into that environment and I think that there is a fair chance that Earl may have some of that dry air wrap into it.  If that happens, then the dry air will tend to weaken the storm.  Hurricane Opal got a shot of dry air and it actually acted as a steroid shot for a few hours and the intensity jumped unexpectedly but then it fell quickly when that dry air got into the core.  I believe that there is a chance that some dry air intrusion may take place. If so , that  would be good news.  Nevertheless, I believe the big story with Earl will be the ultimate track.

08.31.10 18Z Hurricane Earl Spaghetti Models Intensity

The spaghetti models have been consistently keeping the storm off the coast, though some recent runs had a model or two taking the storm inland in Maine or one even had it going in farther south in New England.  The National Hurricane Center has been inching the official forecast ever so slightly westward for each of the most recent forecast tracks and has been pretty consistent in keep their forecast track  to the left of the model consensus track.  No one can say for certain at this point because it comes down to a matter of hours in regard to the trof digging into the East Coast.  6 hours difference in the timing would result in the difference of a major hurricane running right along the coast or running up say 80 miles offshore.  While both scenarios would bring significant effects to the East Coast, a storm running just off the coast would be probably the worst case scenario.  In that worst case scenario in my mind, the eye of the hurricane would remain over water so the intensity would not drop all that quickly.  Meantime, coastal residents from North Carolina to Maine would feel the effects of a major hurricane, storm surge, winds and all. 

18Z 08.31.10 Hurricane Earl Spaghetti Model

There remain many scenarios as there are still several days for this to play out.  However, I think its safe to say that residents of the Eastern Seaboard will feel the effects of a hurricane by the end of the week.  The question is how much of an effect and no one can say with certainty what the answer to that question is.  However, places like the outerbanks of North Carolina, the Virginia Coast, Long Island and Cape Cod will get the worst of whatever Earl has to offer.  The history of hurricanes running up the East Coast is filled with examples of storms that weren’t too terrible, but there are also some glaring examples of storms that brought extreme devastation and loss of life.  While we can’t avoid any devastation, there is no reason for loss of life as the potential is great enough with this storm for everyone to know that the better part of valor is to get out of the way.  Remember, estimates suggest that a hurricane at its peak can release 10 to the power of 15 watts of total energy which equates to about 500,000 Hiroshima-type atomic bombs every day.  Hurricane Earl quite literally is the most powerful force on the face of the earth right now and that is a battle man cannot win.

Hurricane Earl NHC Forecast 5PM 08.31.10

WTNT42 KNHC 312043
TCDAT2
HURRICANE EARL DISCUSSION NUMBER  26
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072010
500 PM AST TUE AUG 31 2010

ALTHOUGH THE SATELLITE PRESENTATION IS NOT AS IMPRESSIVE AS IT WAS
EARLIER...A RECONNAISSANCE PLANE AROUND 1700 UTC REPORTED A MINIMUM
PRESSURE OF 940 MB AND MAXIMUM FLIGHT-LEVEL WINDS OF 128 KNOTS.
THESE DATA SUPPORT AN INITIAL INTENSITY OF 115 KNOTS.
CURRENTLY...THERE IS SOME SOUTHWESTERLY SHEAR DISRUPTING THE
UPPER-LEVEL OUTFLOW OVER THE WESTERN SEMICIRCLE OF EARL.  THIS SHEAR
IS CAUSED BY A WEAK UPPER-LOW OR TROUGH OVER THE EASTERN BAHAMAS AS
OBSERVED ON WATER VAPOR IMAGES.  HOWEVER...MODELS WEAKEN THE UPPER
LOW AS EARL MOVES AROUND IT...RESULTING IN A MORE FAVORABLE
ENVIRONMENT. EARL IS EXPECTED TO MAINTAIN ITS CATEGORY FOUR
INTENSITY FOR THE NEXT DAY OR TWO.

EARL HAS BEGUN TO MOVE TOWARD THE NORTHWEST OR 305 DEGREES AT 12 OR
13 KNOTS DURING THE PAST FEW HOURS. THE SUBTROPICAL HIGH THAT IS
STEERING EARL TOWARD THE WEST-NORTHWEST OR NORTHWEST IS FORECAST TO
GRADUALLY SHIFT EASTWARD AS A BROAD TROUGH BECOMES ESTABLISHED OVER
THE EASTERN UNITED STATES. THIS PATTERN WILL FORCE EARL ON A MORE
NORTHWESTERLY AND NORTHERLY TRACK FOR THE NEXT DAY OR TWO.
THEREAFTER...EARL WILL REACH THE BASE OF THE MID-LATITUDE WESTERLIES
AND WILL LIKELY TURN SHARPLY TO THE NORTHEAST WITH AN INCREASE IN
FORWARD SPEED.  THIS IS THE SOLUTION UNANIMOUSLY PROVIDED BY TRACK
GUIDANCE.  ONCE AGAIN THE OFFICIAL FORECAST HAS BEEN SHIFTED A FEW
MILES TO THE WEST BEFORE 48 HOURS FOLLOWING THE TRENDS OF THE ECMWF
AND THE GFS.

GIVEN THE LARGE AREA OF TROPICAL STORM FORCE WINDS ASSOCIATED WITH
EARL...AND THE NEW DEFINITION OF WATCHES AND WARNINGS...A HURRICANE
AND TROPICAL STORM WATCH HAS BEEN ISSUED FOR A PORTION OF THE MID-
ATLANTIC COAST.

INTERESTS FROM VIRGINIA NORTHWARD TO NEW ENGLAND SHOULD MONITOR THE
PROGRESS OF EARL. 

FORECAST POSITIONS AND MAX WINDS

INITIAL      31/2100Z 22.0N  68.8W   115 KT
 12HR VT     01/0600Z 23.3N  70.5W   115 KT
 24HR VT     01/1800Z 25.6N  72.8W   115 KT
 36HR VT     02/0600Z 28.0N  74.5W   115 KT
 48HR VT     02/1800Z 31.0N  75.5W   115 KT
 72HR VT     03/1800Z 36.0N  73.5W    95 KT
 96HR VT     04/1800Z 44.0N  65.0W    75 KT
120HR VT     05/1800Z 56.0N  55.0W    50 KT...POST-TROP/EXTRATROP

$$
FORECASTER AVILA