Tropical Storm ERNESTO

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TROPICAL STORM ERNESTO DISCUSSION NUMBER  21
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052006
500 PM EDT TUE AUG 29 2006

DURING THE DAY...ERNESTO BECAME SOMEWHAT MORE ORGANIZED-LOOKING ON
RADAR AND SATELLITE IMAGES.  RECENTLY...HOWEVER...THE PRESENTATION
HAS BECOME A BIT RAGGED-LOOKING ON THE IMAGERY.  FLIGHT-LEVEL WINDS
HAVE NOT INCREASED...AND THE FALL IN CENTRAL PRESSURE THIS
AFTERNOON WAS ROUGHLY COMMENSURATE WITH THE TYPICAL SEMI-DIURNAL
PRESSURE CHANGE.  IN OTHER WORDS...ERNESTO IS NOT STRENGTHENING. 
IT IS SOMEWHAT PUZZLING WHY THE TROPICAL CYCLONE HAS NOT
INTENSIFIED TODAY.  ONE NEGATIVE FACTOR MIGHT BE MODEST EASTERLY
SHEAR AS SUGGESTED BY WATER VAPOR IMAGES AND A WESTWARD TILT OF THE
VORTEX WITH HEIGHT AS IMPLIED BY CENTER POSITION ESTIMATES FROM
AIRCRAFT FLYING AT 1500 AND 7500 FEET AS WELL AS WSR-88D RADAR. 
THERE IS STILL A NARROW WINDOW OF OPPORTUNITY FOR ERNESTO TO GAIN
SOME STRENGTH BEFORE REACHING FLORIDA...BUT THAT WINDOW WILL SOON
CLOSE.  AFTER ERNESTO MOVES BACK OVER WATER AND APPROACHES THE
SOUTHEAST U.S. COAST...DYNAMICAL GUIDANCE SUGGESTS THAT THE SYSTEM
COULD APPROACH HURRICANE STRENGTH.  THEREFORE A HURRICANE WATCH HAS
BEEN ISSUED FOR PORTIONS OF THE GEORGIA COAST...THE SOUTH CAROLINA
COAST...AND A PORTION OF THE NORTH CAROLINA COAST.

LATEST CENTER FIXES INDICATE A GENERALLY NORTHWESTWARD
MOTION...320/11...HAS CONTINUED.  HOWEVER...THE HEADING IS LIKELY
TO TURN TOWARD THE NORTH WITHIN THE NEXT 12 TO 24 HOURS AS ERNESTO
ROUNDS THE WESTERN END OF A DEEP-LAYER RIDGE.  THE OFFICIAL
FORECAST TRACK IS FAIRLY SIMILAR TO THE PREVIOUS ONE THROUGH 48
HOURS...AND CONTINUES TO BE NEAR THE EASTERN SIDE OF THE GUIDANCE
ENVELOPE.  IN A DAY OR SO...THE TROPICAL CYCLONE SHOULD ACCELERATE
SOMEWHAT OVER THE CENTRAL FLORIDA PENINSULA AHEAD OF A TROUGH
APPROACHING THE SOUTHEASTERN UNITED STATES.  THE FLOW BETWEEN THE
TROUGH AND THE RIDGE TO THE SOUTHEAST SHOULD MOVE ERNESTO BACK
INLAND OVER THE SOUTHEASTERN U.S. IN A COUPLE OF DAYS.  IN THE
LATTER PART OF THE FORECAST PERIOD...SOME SLOWING OF THE FORWARD
SPEED IS EXPECTED AS ERNESTO OR ITS EXTRATROPICAL REMNANT
ENCOUNTERS A BLOCKING PATTERN NEAR THE NORTHEASTERN UNITED STATES
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      29/2100Z 24.3N  80.2W    40 KT
 12HR VT     30/0600Z 25.6N  80.9W    55 KT...INLAND
 24HR VT     30/1800Z 27.5N  81.1W    50 KT...INLAND
 36HR VT     31/0600Z 29.9N  80.6W    55 KT
 48HR VT     31/1800Z 32.5N  79.7W    60 KT
 72HR VT     01/1800Z 37.0N  78.5W    30 KT...INLAND
 96HR VT     02/1800Z 40.5N  78.0W    25 KT...EXTRATROPICAL
120HR VT     03/1800Z 43.0N  78.0W    25 KT...EXTRATROPICAL
 
$$
FORECASTER PASCH
 
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