[Tropical] Tropical Cyclone Discussion

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WTNT42 KNHC 252029
TCDAT2
TROPICAL STORM EARL DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072010
500 PM AST WED AUG 25 2010

THE FIFTH TROPICAL STORM OF THE SEASON...TROPICAL STORM EARL...HAS
FORMED IN THE EASTERN ATLANTIC...ONE WEEK EARLIER THAN CLIMATOLOGY.
HIGH RESOLUTION SATELLITE IMAGES SHOW THAT THE CIRCULATION HAS
CONTINUE TO GROW AND THE CONVECTION...BOTH IN CLUSTERS AND CURVED
BANDS HAS CONTINUE TO BECOME BETTER ORGANIZED. T-NUMBERS FROM TAFB
AND SAB HAVE REACHED 3.0 AND 2.5 ON THE DVORAK SCALE INDICATING
THAT THE WINDS HAVE INCREASED TO AT LEAST 35 KNOTS. MOST OF THE
GLOBAL MODELS AS WELL AS SHIPS GUIDANCE DEPICT AN ENVIRONMENT OF
RELATIVELY LOW SHEAR ACROSS THE TROPICAL ATLANTIC. THE LOW SHEAR
COMBINED WITH UNUSUALLY WARM OCEAN WOULD FAVOR A GRADUAL
STRENGTHENING. THE OFFICIAL FORECAST CALLS FOR EARL TO BECOME A
HURRICANE IN ABOUT TWO DAYS.

THE BEST ESTIMATE OF THE INITIAL MOTION IS 275/14 KNOTS. MOST OF THE
GLOBAL MODELS SHOW A PERSISTENT SUBTROPICAL RIDGE EXTENDING
FROM AFRICA TO NEAR 60 DEGREES WEST. THIS STEERING PATTERN WILL
LIKELY KEEP THE CYCLONE ON A GENERAL WESTWARD TRACK FOR THE NEXT 3
TO 4 DAYS. A GRADUAL TURN MORE TO THE WEST-NORTHWEST IS FORECAST AT
THE END OF THE FORECAST PERIOD AS THE CYCLONE REACHES THE WESTERN
EDGE OF THE SUBTROPICAL RIDGE.  THE OFFICIAL FIVE DAY FORECAST
POSITION WAS ADJUSTED SOUTHWARD A LITTLE BIT...AND IS BASICALLY ON
TOP OF THE GFS AND THE ECMWF LOCATION FOR THAT TIME PERIOD. THIS WAS
BASED ON THE REMARKABLY GOOD AGREEMENT OF THESE TWO RELIABLE MODELS
IN FIVE DAYS. ALTHOUGH MOST OF THE GUIDANCE HAS SHIFTED SOUTHWARD A
LITTLE BIT...THE CORE OF THE CYCLONE IS STILL FORECAST TO PASS TO
THE NORTH OF THE LEEWARD ISLANDS. LETS SEE WHAT HAPPENS IN THE
NEXT MODEL CYCLE.


FORECAST POSITIONS AND MAX WINDS

INITIAL      25/2100Z 14.4N  32.2W    35 KT
 12HR VT     26/0600Z 14.6N  34.6W    40 KT
 24HR VT     26/1800Z 15.0N  38.0W    45 KT
 36HR VT     27/0600Z 15.5N  41.0W    55 KT
 48HR VT     27/1800Z 16.0N  44.0W    65 KT
 72HR VT     28/1800Z 17.0N  50.0W    75 KT
 96HR VT     29/1800Z 18.0N  55.0W    80 KT
120HR VT     30/1800Z 20.0N  60.0W    80 KT

$$
FORECASTER AVILA


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