[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 220003
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN SEP 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC.

...SPECIAL FEATURES...
WHAT REMAINS OF A SURFACE LOW PRESSURE CENTER THAT WAS OVER
THE NORTHEASTERN CARIBBEAN SEA SIX HOURS AGO NOW IS INLAND
IN CENTRAL AND WESTERN PUERTO RICO. THE DATA FROM THE AIR FORCE
RECONNAISSANCE FLIGHT DO NOT SHOW A WELL-DEFINED SURFACE
CIRCULATION CENTER YET. THE LOW CENTER IS EXPECTED TO MOVE
GENERALLY NORTHWARD DURING THE NEXT DAY OR TWO...AND IT MAY
BECOME A TROPICAL DEPRESSION AT ANY TIME. LOCALLY HEAVY RAINFALL
WILL CONTINUE OVER PUERTO RICO AND THE U. S. AND BRITISH VIRGIN
ISLANDS THROUGH MONDAY. THESE RAINS MAY CAUSE LIFE-THREATENING
FLASH FLOODS AND MUDSLIDES. EVERYONE IN PUERTO RICO...THE U.S.
AND BRITISH VIRGIN ISLANDS...AND EASTERN HISPANIOLA SHOULD
MONITOR THE PROGRESS OF THIS SYSTEM AND ANY WATCHES OR WARNINGS
ISSUED BY THE RESPECTIVE WEATHER FORECAST OFFICES.
NUMEROUS STRONG SHOWERS AND THUNDERSTORMS ARE FROM 17N TO 19N
BETWEEN 65W AND 67W AROUND AND ON TOP OF PUERTO RICO. OTHER
SHOWERS AND THUNDERSTORMS ARE WITHIN A 30 NM RADIUS OF 20N60W...
18N62W...AND 15N67W. ISOLATED AND DISORGANIZED SHOWERS AND
POSSIBLE THUNDERSTORMS ARE IN THE DOMINICAN REPUBLIC FROM 18N
TO 19N BETWEEN 70W AND 72W. ISOLATED MODERATE SHOWERS ARE IN
HAITI FROM THE NORTHEASTERN CORNER TO THE SOUTHWESTERN CORNER.
WARMING CLOUD TOP TEMPERATURES AND DISSIPATING BUT LINGERING
CONVECTIVE PRECIPITATION FROM 15N TO 16N BETWEEN 63W AND 65W.

...TROPICAL WAVES...
AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 25W/26W SOUTH OF 17N
MOVING WEST 10 TO 15 KT. ISOLATED DISORGANIZED SHOWERS AND
THUNDERSTORMS ARE FROM 10N TO 14N BETWEEN 24W AND 30W.

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 40W/41W SOUTH OF 20N
MOVING WEST 10 TO 15 KT. LOW CLOUDS ARE AROUND THE WAVE FROM
10N TO 20N BETWEEN 37W AND 42W.

A TROPICAL WAVE IS ENTERING THE EASTERN CARIBBEAN SEA ALONG
60W/61W SOUTH OF 20N MOVING WEST 10 TO 15 KT. SHOWERS AND
THUNDERSTORMS ARE WITHIN A 15 NM TO 30 NM RADIUS OF 20N60W...
18N62W...AND FROM 16N TO 17N BETWEEN 61W AND 62W.

A TROPICAL WAVE IS ALONG 86W/87W SOUTH OF 21N MOVING WEST 10 TO
15 KT PASSING THROUGH HONDURAS AND NICARAGUA. NUMEROUS STRONG
SHOWERS AND THUNDERSTORMS ARE IN THE YUCATAN PENINSULA NORTH OF
20N.

...THE ITCZ...
ALONG 10N/11N BETWEEN 15W AT THE AFRICA COAST AND 25W...10N29W
7N40W 7N50W 8N59W. STRONG SHOWERS AND THUNDERSTORMS FROM 3N TO
4N BETWEEN 36W AND 40W...AND FROM 6N TO 8N BETWEEN 44W AND 48W.

...DISCUSSION...

THE GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL SURFACE TROUGH IS INLAND THROUGH CENTRAL
LOUISIANA TO CENTRAL TEXAS. AN UPPER LEVEL RIDGE COVERS THE GULF
OF MEXICO FROM THE SOUTHWESTERN CORNER OF THE AREA NORTHEASTWARD
BEYOND NORTH FLORIDA. A SURFACE TROUGH IS ALONG 19N93W 24N94W
27N94W. DISORGANIZED SHOWERS ARE SOUTH OF 22N BETWEEN THE
YUCATAN PENINSULA AND MEXICO. OTHER SHOWERS AND POSSIBLE
THUNDERSTORMS ARE IN BROAD SURFACE LOW PRESSURE UNDER THE RIDGE
FROM 25N TO 28N BETWEEN 85W AND 86W.

FROM THE ATLANTIC OCEAN INTO THE NORTHWESTERN CARIBBEAN SEA...
AND THE CARIBBEAN SEA WEST OF 70W...
A MIDDLE TO UPPER LEVEL TROUGH IS ALONG 31N75W TO 27N76W ACROSS
THE BAHAMAS TO 23N78W. THE TROUGH CONTINUES ACROSS CUBA INTO THE
NORTHWESTERN CARIBBEAN SEA TO 19N82W 17N86W THROUGH CENTRAL
HONDURAS TO THE EL SALVADOR/NICARAGUA BORDER. A SURFACE TROUGH
PASSES THROUGH 32N74W TO THE FLORIDA COAST NEAR 29N81W. ISOLATED
MODERATE SHOWERS ARE WEST OF 74W. UPPER LEVEL ANTICYCLONIC FLOW
COVERS THE CARIBBEAN SEA BETWEEN 70W AND 80W.
NUMEROUS STRONG SHOWERS AND THUNDERSTORMS COVER THE AREA FROM 13N
IN NICARAGUA TO 15N IN HONDURAS BETWEEN 87W AND 88W IN EASTERN
EL SALVADOR. THE 31N75W-TO-17N86W TROUGH ALSO EXTENDS INTO THE
EASTERN PACIFIC OCEAN NEAR 8N87W. ISOLATED MODERATE SHOWERS TO
LOCALLY STRONG THUNDERSTORMS EXTEND FROM WESTERN PANAMA TO
NORTHERN COSTA RICA...INTO WESTERN NICARAGUA...AND SPREAD OUT
ACROSS HONDURAS. CONVECTIVE DEBRIS CLOUDS COVER THE CARIBBEAN
SEA WATERS AND CENTRAL AMERICA SOUTH OF 15N WEST OF 81W.
ISOLATED MODERATE SHOWERS IN UPPER LEVEL DIFFLUENT FLOW ARE FROM
14N TO 17N BETWEEN 79W AND 83W. STRONG SHOWERS AND THUNDERSTORMS
IN SOUTHERN GUATEMALA ARE IN ALSO IN AN AREA OF UPPER LEVEL
DIFFLUENT FLOW.

THE REST OF THE CARIBBEAN SEA EAST OF 70W...
THE SPECIAL FEATURE LOW PRESSURE CENTER IS INLAND IN PUERTO RICO.
OVERCAST HIGH CLOUDS COVER PRACTICALLY THE ENTIRE AREA NORTH OF
10N EAST OF 70W. MIDDLE TO UPPER LEVEL EASTERLY FLOW APPROACHES
THE EASTERN CARIBBEAN SEA FROM THE ATLANTIC OCEAN.

THE REST OF THE ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR
26N63W. A MIDDLE TO UPPER LEVEL CENTRAL ATLANTIC OCEAN TROUGH
GOES FROM 28N42W TO A CYCLONIC CIRCULATION CENTER NEAR 23N47W
TO 16N48W. AN EASTERN ATLANTIC OCEAN MIDDLE TO UPPER LEVEL
TROUGH PASSES THROUGH 32N13W TO A CYCLONIC CIRCULATION CENTER
NEAR 29N23W TO 22N24W. ISOLATED MODERATE SHOWERS ARE NORTH OF
29N BETWEEN 30W AND 40W.

$$
MT




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