Tropical Storm Warnings Hoisted in Keys; Hurricane Watch For Gold Coast


Fay is getting close enough to coastal radar installations to track its approach using this National Interactive Radar (Click Here).  You will find it centered on the Ohio Valley but it can be moved anywhere in the country to street level and also be looped.  It also provides some computer generated analysis of any particular storm cluster.

Fay 5pm 0817 NHC Fcst Track

Fay 5pm 0817 NHC Fcst Track

At 5pm Sunday, A Hurricane Watch was up for the SW Florida Coast, a Tropical

Fay Spaghetti Model 18Z 0817

Fay Spaghetti Model 18Z 0817

Storm Watch for the SE Florida Coast and a Tropical Storm Warning was in effect for the Keys.

The general forecast remains the same with Tropical Storm Fay running just south of the southern coast of Cuba…the circulation just over water so it doesn’t get killed but enough of it over Cuba to prevent rapid intensification.  It should slow its forward speed as it turns and then emerges just Southwest of Key West.  From that point, as it moves on a more northerly trajectory, it will have an opportunity to develop to the point that a hurricane of 85 mph or so will move into Florida’s Gold Coast near Tampa on Tuesday and then it moves west of Jacksonville, west of Savannah an east of Atlanta and eventually into

Fay NHC Fcst Track 5 PM 08/17 NRL Graphic

Fay NHC Fcst Track 5 PM 08/17 NRL Graphic

western Virginia or even eastern Kentucky.  Now, you will note the cone for the outlying period is pretty far west. That is because there have been a couple of

Fay Spaghetti Intensity Graph 18Z 0817

Fay Spaghetti Intensity Graph 18Z 0817

models that have insisted on taking the storm farther west. If you look at the spaghetti model map, you will find more than a few suggesting that.  It still seems improbable to me because there is a trof that is moving across the Ohio Valley on Wednesday that should pick up the storm.  I suppose that the scenario for it to be farther west would be for it to move farther west in the Gulf and slip under the trof.  If that were to occur, then the whole forecast is off the mark and so far the boys at the NHC have handled this one very well.  As I said in a previous post, if it doesn’t slow down before it starts to get influenced north, then it will swing wider out into the Gulf.  But the NHC still feels like it will slow its forward progress and make a pretty tight turn from WNW to N. How it turns and when it turns will determine the intensity as that will determine how long its over open water.  If you look at the spaghetti intensity graph you will see huge differences.  Here is the 5 pm discussion from the NHC:

TROPICAL STORM FAY DISCUSSION NUMBER   9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL062008
500 PM EDT SUN AUG 17 2008

FAY HAS BECOME A LITTLE BETTER ORGANZIED IN SATELLITE AND RADAR
IMAGERY THIS AFTERNOON…WITH INCREASED CURVED BANDS OF CONVECTION
NEAR THE CENTER IN THE NORTHEASTERN SEMICIRCLE.  HOWEVER…THERE
ARE SINGS OF SOUTHWESTERLY VERTICAL WIND SHEAR AND DRY AIR
ENTRAINMENT IN THE WESTERN SEMICIRCLE…WHERE THERE IS LITTLE IN
THE WAY OF ORGANIZED CONVECTION OR STRONG WINDS.  AN AIR FORCE
RESERVE HURRICANE HUNTER AIRCRAFT RECENTLY REPORTED A CENTRAL
PRESSURE OF 1003 MB…ALTHOUGH THE PLANE HAS NOT YET SAMPLED THE
WINDS IN THE NORTHEASTERN QUADRANT.  THE INITIAL INTENSITY REMAINS
45 KT BASED ON CONTINUITY AND A 45 KT SATELLITE INTENSITY ESTIMATE
FROM TAFB.

THE CENTER OF FAY SURGED TOWARD THE WEST-NORTHWEST DURING THE
DAY…AT ONE TIME MOVING BETWEEN 18-20 KT.  THAT MOTION APPEARS TO
HAVE ENDED…AND THE INITIAL MOTION FOR THIS ADVISORY IS A SOMEWHAT
UNCERTAIN 300/13.  FAY IS APPROACHING A DEVELOPING WEAKNESS IN A
LOW/MID LEVEL RIDGE OVER THE GULF OF MEXICO…WHICH IS DEVELOPING
DUE TO A MID/UPPER-LEVEL TROUGH OVER THE SOUTHERN UNITED STATES.
THIS PATTERN SHOULD ALLOW FAY TO TURN MORE NORTHWARD AFTER 24 HR…
BUT THERE REMAINS SIGNIFICANT DISAGREEMENT BETWEEN THE MODELS ON
HOW MUCH OF A TURN WILL OCCUR.  THE ECMWF AND CANADIAN MODELS
CONTINUE TO FORECAST A SHARPER TURN WITH LANDFALL IN SOUTHWESTERN
FLORIDA…WITH THE ECMWF SHOWING FAY CROSSING TO THE ATLANTIC THEN
MOVING WESTWARD TO HIT FLORIDA AGAIN.  THE GFS AND GFDL HAVE
SHIFTED WEST SINCE THEIR PREVIOUS RUNS…WHILE THE UKMET HAS
SHIFTED A LITTLE TO THE EAST.  THESE MODELS HAVE JOINED THE HWRF IN
CALLING FOR A TRACK NEAR OR JUST OVER THE WEST COAST OF THE FLORIDA
PENINSULA.  THE NOGAPS CONTINUES TO FORECAST A NORTH-NORTHWESTWARD
MOTION TOWARD THE FLORIDA PANHANDLE.  OVERALL…THE GUIDANCE
ENVELOPE HAS SHIFTED TO THE WEST SINCE THE PREVIOUS PACKAGE…
POSSIBLY DUE TO THE CHANGE IN THE INITIAL POSITION CAUSED BY THE
MOTION SURGE.  THE FORECAST TRACK IS SHIFTED ABOUT 60 N MI TO THE
WEST OF THE PREVIOUS PACKAGE…BUT LIES TO THE EAST OF THE CENTER
OF THE GUIDANCE ENVELOPE AND THE CONSENSUS MODELS.  THE NEW TRACK
IS IN BEST AGREEMENT WITH THE HWRF.

THE INTENSITY FORECAST REMAINS PROBLEMATIC.  THE SHIPS MODEL NOW
FORECASTS PERSISTENT WIND SHEAR DURING THE FORECAST PERIOD…WITH
PERHAPS A PERIOD OF LIGHTER SHEAR FROM 18-48 HR.  THE LARGE-SCALE
MODELS HAVE A VARIETY OF SOLUTIONS FOR THE CURRENT UPPER-LEVEL
TROUGH WEST OF FAY OVER THE GULF OF MEXICO AND THE CARIBBEAN…WITH
NO CLEAR EVIDENCE AT THIS TIME OF WHICH IS CORRECT.  IT APPEARS THE
SHEAR WILL BE LIGHT ENOUGH TO ALLOW FAY TO GRADUALLY STRENGTHEN AS
SHOWN IN THE GFDL MODEL…AND THE NEW INTENSITY FORECAST THUS CALLS
FOR INTENSIFICATION ALONG THOSE LINES.  IT SHOULD BE NOTED THAT THE
HWRF CALLS FOR FAY TO BECOME A CATEGORY 2 HURRICANE OVER THE
EASTERN GULF OF MEXICO…WHILE THE SHIPS MODEL FORECAST A PEAK JUST
BELOW HURRICANE STRENGTH.

THE FORECAST TRACK SITUATION IS SIMILAR TO THAT OF HURRICANE CHARELY
FROM AUGUST 2004…IN THAT A SMALL CHANGE IN THE TRACK OF THE STORM
COULD MAKE A BIG DIFFERENCE IN THE EVETUAL LANDFALL LOCATION.  THE
NHC WIND SPEED PROBABILITIES PRODUCT SHOWS ABOUT AN EQUAL CHANCE OF
HURRICANE-FORCE WINDS FOR THE ENTIRE WEST COAST OF THE FLORIDA
PENINSULA.

FORECAST POSITIONS AND MAX WINDS

INITIAL      17/2100Z 21.0N  80.2W    45 KT
12HR VT     18/0600Z 22.3N  81.7W    50 KT…INLAND
24HR VT     18/1800Z 23.8N  82.8W    55 KT…OVER WATER
36HR VT     19/0600Z 25.3N  83.1W    65 KT
48HR VT     19/1800Z 27.0N  83.2W    75 KT
72HR VT     20/1800Z 30.0N  83.0W    65 KT…INLAND
96HR VT     21/1800Z 33.5N  82.0W    30 KT…INLAND
120HR VT     22/1800Z 37.0N  82.0W    20 KT…INLAND REMNANT LOW

$$
FORECASTER BEVEN

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