[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210602
TWDAT

TROPICAL WEATHER DISCUSSION...
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU AUG 21 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0345 UTC.

...SPECIAL FEATURES...
TROPICAL STORM FAY IS CENTERED NEAR 29.1N 80.7W OR ABOUT 17 NM
EAST-SOUTHEAST OF DAYTONA BEACH FLORIDA AT 21/0600 UTC. FAY IS
IS DRIFTING NORTHWESTWARD NEAR 2 KT OVER THE PAST FEW HOURS AND
IS EXPECTED TO SLOWLY MOVE WEST-NORTHWEST LATER THIS MORNING.
CENTRAL PRESSURE REPORTED BY THE RECONNAISSANCE AIRCRAFT WAS 993
MB. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO 60 KT.
PLEASE SEE THE LATEST NHC THE FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT1/WTNT21 KNHC AND PUBLIC ADVISORY UNDER
AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC FOR MORE DETAILS. THE
UPPER HIGH ASSOCIATED WITH FAY REMAINS ELONGATED E/W PROVIDING
OUTFLOW OVER THE W ATLC TO 72W AND THE GULF OF MEXICO TO 87W.
SCATTERED/HEAVY SHOWERS WITH EMBEDDED ISOLATED THUNDERSTORMS ARE
INLAND OVER NE FLORIDA FROM JUST S OF MELBOURNE TO JUST S OF
JACKSONVILLE AND IN THE W ATLC WATERS FROM 27N-31N W OF 80W.
HEAVY SHOWERS WITH EMBEDDED THUNDERSTORMS ARE IN THE W ATLC
WATERS FROM 26N-31N BETWEEN 75W-80W. SOME SLIGHT STRENGTHENING
IS POSSIBLE WHILE THE CENTER OF FAY REMAINS OVER WATER THIS
MORNING...BUT GRADUAL WEAKENING IS FORECAST LATER TODAY AND
FRIDAY AS FAY IS FORECAST TO MOVE VERY SLOWLY ACROSS THE
NORTHERN FLORIDA PENINSULA TODAY...AND NEAR THE GULF COAST IN
THE FLORIDA BIG BEND AREA ON FRIDAY. FAY IS EXPECTED TO PRODUCE
ADDITIONAL RAINFALL ACCUMULATIONS OF 5 TO 10 INCHES OVER
EAST-CENTRAL AND NORTHEASTERN FLORIDA...WITH 3 TO 6 INCHES OVER
SOUTHEASTERN GEORGIA. ISOLATED STORM TOTAL AMOUNTS OF 30 INCHES
ARE POSSIBLE IN FLORIDA. THE MELBOURNE NATIONAL WEATHER SERVICE
FORECAST OFFICE REPORTS RAINFALL TOTALS OF NEARLY 25 INCHES IN
PARTS OF NORTH MELBOURNE. ADDITIONAL ACCUMULATIONS OF 1 TO 3
INCHES ARE POSSIBLE IN THE EXTREME NORTHWESTERN BAHAMAS.

...TROPICAL WAVES...
A NEW TROPICAL WAVE ALONG 29W/30W S OF 19N WITH A 1008 MB LOW
ALONG THE WAVE NEAR 11N WAS ADDED TO THE 0000Z SURFACE ANALYSIS
BASED ON SATELLITE IMAGERY...SURFACE OBSERVATIONS AND A QSCAT
PASS THAT SHOWS A WELL DEFINED WIND SHIFT ASSOCIATED WITH THE
WAVE AS WELL AS A BROAD CYCLONIC CIRCULATION ALONG THE WAVE AXIS
NEAR 11N. WAVE IS EMBEDDED WITHIN SOME DRY AIR...THUS NO
ASSOCIATED SHOWER ACTIVITY/CONVECTION.

A WEAK 1007 MB LOW IS ANALYZED IN THE CENTRAL ATLC NEAR 12N43W
MOVING W NEAR 15 KT. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS REMOVED FROM THE LOW NW FROM 11N-15N BETWEEN
45W-48W.

TROPICAL WAVE IN THE W TROPICAL ATLC IS ALONG 53W S OF 18N
MOVING W NEAR 10 KT. NO ASSOCIATED SHOWER ACTIVITY/CONVECTION.

TROPICAL WAVE IN THE CENTRAL CARIBBEAN IS ALONG 73W S OF 21N
MOVING W NEAR 15 KT. NO ASSOCIATED SHOWERS/CONVECTION.

...THE ITCZ...
THE ITCZ IS CENTERED ALONG 14N16W 13N27W 11N34W 12N51W 9N62W.
SCATTERED MODERATE/STRONG CONVECTION IS FROM 5N-11N BETWEEN
33W-37W WITH CLUSTERS OF SIMILAR CONVECTION FROM 6N-11N W OF 37W
TO INLAND OVER SOUTH AMERICA.

...DISCUSSION...

GULF OF MEXICO...
WIDELY ISOLATED SHOWERS ARE ALL THAT REMAIN OF T.S. FAY IN THE E
GULF N OF 26N E OF 85W ACROSS THE FLORIDA PENINSULA. AN UPPER
LOW IS MOVING NE OVER ARKANSAS EXTENDING AN UPPER TROUGH OVER
TEXAS TO THE GULF COAST GENERATING A SMALL AREA OF SHOWERS/
THUNDERSTORMS N OF 29N NEAR THE LOUISIANA/TEXAS BORDER. THE
UPPER LEVEL RIDGE ANCHORED OFF THE W COAST OF MEXICO EXTENDS
INTO THE SW GULF ALONG 22N TO 90W WITH A SECOND UPPER RIDGE
ANCHORED S OF W CUBA COVERING THE SE GULF. A SURFACE TROUGH IS
INLAND OVER THE YUCATAN PENINSULA GENERATING SHOWERS AND
SCATTERED THUNDERSTORMS IN THE E BAY OF CAMPECHE S OF 21N E OF
93W. THE REMAINDER OF THE GULF REMAINS RATHER CLEAR THIS MORNING
WITH A WEAK 1014 MB HIGH OFF THE SE COAST OF LOUISIANA NEAR
28N89W.

CARIBBEAN SEA...
AN INDUCED INVERTED UPPER TROUGH EXTENDS FROM S NICARAGUA TO THE
MONA PASSAGE SEPARATING AN UPPER RIDGE ANCHORED NEAR THE ISLE OF
YOUTH OFF THE W COAST OF CUBA AND A SECOND UPPER RIDGE ANCHORED
IN THE W TROPICAL ATLC E OF THE LEEWARD ISLANDS. THE ITCZ AXIS
EXTENDS FROM COLOMBIA OVER PANAMA INTO THE E PACIFIC GENERATING
SCATTERED SHOWERS/THUNDERSTORMS S OF 12N BETWEEN 75W-79W.
CLUSTERS OF SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN 90 NM
ALONG THE S COAST OF CUBA. EASTERLY TRADE WINDS HAVE INCREASED
OVER THE PAST 24 HOURS AND COUPLED WITH ADVECTED TROPICAL
MOISTURE FROM THE UPPER RIDGE OVER THE E CARIBBEAN ARE USHERING
IN SOME ISOLATED SHOWERS/THUNDERSTORMS OVER THE AREA E OF 69W.
THE REMAINDER OF THE CARIBBEAN IS DOMINATED BY MODERATE/STRONG
SUBSIDENCE AND DRY STABLE AIR...THUS CLEAR SKIES ELSEWHERE
TONIGHT.

ATLANTIC OCEAN...
THE MAIN CONCERN FOR THE FAR W ATLC AGAIN TONIGHT IS THE
ACTIVITY ASSOCIATED WITH T.S. FAY...SEE SPECIAL FEATURES ABOVE.
AN ELONGATED UPPER LOW IS OVER THE REMAINDER OF THE W ATLC
EXTENDS FROM 30N60W TO THE MONA PASSAGE. A LARGE BENIGN UPPER
LOW COVERS MOST OF THE CENTRAL ATLC CENTERED NEAR 22N52W WITH AN
UPPER HIGH ANCHORED E OF THE LEEWARD ISLANDS NEAR 127N59W. AN
E/W UPPER RIDGE COVERS THE E ATLC. MODERATE SUBSIDENCE AND
SOMEWHAT DRY STABLE AIR COVERS THE ATLC E OF 60W GIVING THE
REMAINDER OF THE AREA FAIR WEATHER CONDITIONS AGAIN TONIGHT. A
SURFACE RIDGE REMAINS OVER MOST OF THE ATLC N OF 23N E OF 70W
ANCHORED BY A SERIES OF HIGHS N OF THE REGION.

$$
WALLACE




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