[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211151
TWDAT

TROPICAL WEATHER DISCUSSION...
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURES...
TROPICAL STORM FAY IS CENTERED NEAR 29.2N 80.7W OR ABOUT 17 NM
EAST OF DAYTONA BEACH FLORIDA AT 21/1200 UTC. FAY HAS BEEN NEAR
STATIONARY OVER THE PAST SEVERAL HOURS AND IS EXPECTED TO SLOWLY
MOVE WEST-NORTHWEST LATER TODAY. MINIMUM CENTRAL PRESSURE AS
MEASURED BY AN AIR FORCE RESERVE UNIT HURRICANE HUNTER AIRCRAFT
IS 994 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 74W AND THE GULF OF MEXICO
TO 86W. SCATTERED/HEAVY SHOWERS WITH EMBEDDED THUNDERSTORMS ARE
WITHIN 120 NM OF THE STORM CENTER. SCATTERED/HEAVY SHOWERS WITH
THUNDERSTORMS ARE WITHIN 60/75 NM OF LINE FROM 23N79W ACROSS THE
N BAHAMA ISLANDS ALONG 27N77W TO 31N79W. OUTER RAIN BANDS OF
SHOWERS WITH EMBEDDED ISOLATED THUNDERSTORMS ARE S OF THE STORM
TO THE FLORIDA STRAITS BETWEEN 77W-79W AND N OF THE STORM TO 34N
W OF 76W TO JUST INLAND OVER SOUTH CAROLINA...GEORGIA...AND FAR
NE FLORIDA.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 31W S OF 19N WITH A 1008 MB LOW ALONG THE
WAVE NEAR 12N MOVING W NEAR 10 KT. WAVE REMAINS EMBEDDED WITHIN
SOME RATHER DRY AIR BUT ISOLATED SHOWERS ARE FROM 13N-16N
BETWEEN 29W-31W.

A SMALL 1007 MB LOW IS ANALYZED IN THE CENTRAL ATLC NEAR 12N46W
MOVING W NEAR 15 KT. CLUSTERS OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS TO THE W OF THE LOW WITHIN 75 NM OF LINE
FROM 12N47W TO 14N52W.

TROPICAL WAVE IN THE W TROPICAL ATLC IS ALONG 54W S OF 18N
MOVING W NEAR 10 KT. NO ASSOCIATED SHOWER ACTIVITY/CONVECTION.

TROPICAL WAVE IN THE CENTRAL CARIBBEAN IS ALONG 74W/75W S OF 20N
MOVING W NEAR 15 KT. NO ASSOCIATED SHOWERS/CONVECTION.

...THE ITCZ...
THE ITCZ IS CENTERED ALONG 13N16W 14N24W 9N37W 8N50W 10N62W.
LARGE CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM
5N-11N W OF 33W TO INLAND OVER SOUTH AMERICA. CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 11N-15N E
OF 19W TO INLAND OVER W AFRICA.

...DISCUSSION...

GULF OF MEXICO...
SHOWER ACTIVITY ASSOCIATED WITH T.S. FAY ARE IN THE E GULF...
SEE SPECIAL FEATURES ABOVE. AN UPPER LOW IS MOVING N OVER
ARKANSAS EXTENDING AN UPPER TROUGH OVER TEXAS INTO THE NW GULF
COAST GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF
28N BETWEEN VERMILION BAY LOUISIANA AND HOUSTON TEXAS. THE UPPER
LEVEL RIDGE ANCHORED OFF THE W COAST OF MEXICO EXTENDS INTO THE
SW GULF ALONG 22N TO 92W WITH A SECOND UPPER RIDGE ANCHORED OVER
W CUBA COVERING THE REMAINDER OF THE S GULF. A WEAK SURFACE
TROUGH IS ALONG THE W COAST OF THE YUCATAN PENINSULA WITH
SCATTERED SHOWERS/THUNDERSTORMS INLAND AND WITHIN 90 NM ALONG
THE COAST OF MEXICO W OF THE TROUGH TO THE TEXAS BORDER. THE
REMAINDER OF THE GULF REMAINS RATHER CLEAR THIS MORNING WITH A
WEAK 1014 MB HIGH OFF THE SE COAST OF LOUISIANA NEAR 28N91W.

CARIBBEAN SEA...
AN INDUCED INVERTED UPPER TROUGH EXTENDS FROM CENTRAL NICARAGUA
TO THE MONA PASSAGE SEPARATING AN UPPER RIDGE ANCHORED OVER W
CUBA AND A SECOND UPPER RIDGE ANCHORED OVER THE LEEWARD ISLANDS.
THE ITCZ AXIS EXTENDS FROM COLOMBIA N OF PANAMA INTO THE E
PACIFIC NEAR THE COSTA RICA BORDER GENERATING SCATTERED SHOWERS/
THUNDERSTORMS S OF 12N BETWEEN 75W-81W. CLUSTERS OF SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 30 NM OF LINE FROM
18N83W TO E CUBA NEAR 20N77W. MODERATE EASTERLY TRADE WINDS
CONTINUE OVER THE AREA AND COUPLED WITH ADVECTED TROPICAL
MOISTURE FROM THE UPPER RIDGE OVER THE E CARIBBEAN ARE USHERING
IN SCATTERED SHOWERS/THUNDERSTORMS S OF 16N E OF 72W. THE
REMAINDER OF THE CARIBBEAN IS DOMINATED BY MODERATE SUBSIDENCE
AND DRY STABLE AIR...THUS CLEAR SKIES ELSEWHERE THIS MORNING.

ATLANTIC OCEAN...
THE MAIN CONCERN FOR THE FAR W ATLC AGAIN THIS MORNING IS THE
ACTIVITY ASSOCIATED WITH T.S. FAY...SEE SPECIAL FEATURES ABOVE.
AN UPPER LOW IS IN THE W ATLC CENTERED NEAR 22N67W COVERING THE
AREA FROM 27N TO THE GREATER ANTILLES BETWEEN 61W-72W. A DEEP
LAYERED TROUGH IS OVER THE NW ATLC TO 30N E OF T.S. FAY WITH THE
ASSOCIATED FRONTAL BOUNDARY N OF THE REGION. HOWEVER...IT IS
INDUCING AN UPPER RIDGE TO THE E OF BERMUDA AND GENERATING
SCATTERED SHOWERS/THUNDERSTORMS N OF 29N FROM 59W-67W. A SECOND
LARGER BENIGN UPPER LOW COVERS MOST OF THE CENTRAL ATLC CENTERED
NEAR 23N53W WITH AN UPPER HIGH ANCHORED OVER THE LEEWARD ISLANDS
NEAR GUADELOUPE. AN E/W UPPER RIDGE COVERS THE E ATLC WITH A
WEAK UPPER TROUGH BEGINNING TO PUSH S OVER THE NE ATLC TO JUST W
OF THE CANARY ISLANDS. MODERATE SUBSIDENCE AND SOMEWHAT DRY
STABLE AIR COVERS THE ATLC E OF 60W GIVING THE REMAINDER OF THE
AREA FAIR WEATHER CONDITIONS AGAIN THIS MORNING. A SURFACE RIDGE
REMAINS OVER MOST OF THE ATLC N OF 23N E OF 72W ANCHORED BY A
SERIES OF HIGHS N OF THE REGION AND A WEAK 1021 MB HIGH S OF
BERMUDA NEAR 29N65W.

$$
WALLACE




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