[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 251756
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI SEP 25 2009

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1715 UTC.

...TROPICAL WAVES...

AN EASTERN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 20N28W TO
A 1012 MB LOW PRESSURE CENTER NEAR 16N30W TO 10N33W...DRIFTING
WESTWARD DURING THE LAST SIX HOURS. SCATTERED MODERATE SHOWERS
TO ISOLATED STRONG THUNDERSTORMS...WITH SOME AREAS OF WARMING
CLOUD TOP TEMPERATURES DURING THE LAST SIX HOURS...COVER THE
AREA FROM 16N TO 20N BETWEEN 28W AND 33W.

A TROPICAL WAVE TO THE SOUTH OF 17N ALONG 60W HAS REACHED THE
EASTERN CARIBBEAN SEA. IT HAS BEEN MOVING WESTWARD 10 KT. WIDELY
SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS COVER
THE AREA FROM 10N TO 14N BETWEEN 55W AND 61W. THE UPPER LEVEL
FLOW IS SHEARING THE TOPS OF THE CLOUDS THAT ARE IN THIS AREA OF
PRECIPITATION.

...THE ITCZ...
FROM 14N17W TO 13N28W TO 12N34W 9N46W 9N56W. STRONG SHOWERS AND
THUNDERSTORMS FROM 6N TO 10N BETWEEN 18W AND 20W...AND FROM 15N
TO 17N BETWEEN 21W AND 22W. MULTILAYERED CONVECTIVE DEBRIS
CLOUDS AND POSSIBLE SHOWERS ARE ELSEWHERE FROM 5N TO 17N BETWEEN
AFRICA AND 23W. WIDELY SCATTERED MODERATE SHOWERS TO ISOLATED
STRONG THUNDERSTORMS FROM 6N TO 10N BETWEEN 48W AND 52W.

...DISCUSSION...

THE GULF OF MEXICO...
UPPER LEVEL ANTICYCLONIC FLOW COVERS PRETTY MUCH THE ENTIRE AREA
EXCEPT FOR THAT PART OF THE GULF OF MEXICO THAT IS TO THE SOUTH
OF 23N. THE ANTICYCLONIC FLOW IS AROUND A CENTER THAT IS NORTH
CENTRAL FLORIDA...WITH A RIDGE THAT GOES FROM THE CENTER TO THE
DEEP SOUTH TEXAS/NORTHEASTERN MEXICO BORDER. A STATIONARY FRONT
LINGERS FROM SOUTHERN LOUISIANA TO 26N95W TO THE NORTHERN COAST
OF THE ISTHMUS OF TEHUANTEPEC OF MEXICO. SHOWERS AND
THUNDERSTORMS ARE TO THE WEST OF 93W TO THE SOUTH OF 27N...AND
IN SOUTHEASTERN COASTAL LOUISIANA. POSSIBLE SHOWERS ARE IN THE
SOUTHEASTERLY SURFACE WIND FLOW EVERYWHERE TO THE EAST OF THE
STATIONARY FRONT. ONE UPPER LEVEL CYCLONIC CIRCULATION CENTER
IS TO THE SOUTH OF THE WESTERN TIP OF CUBA. A SECOND CYCLONIC
CENTER IS JUST OFF THE WESTERN SIDE OF THE YUCATAN PENINSULA.
CYCLONIC FLOW COVERS THE AREA TO THE SOUTH OF 23N BETWEEN THE
YUCATAN PENINSULA AND THE REST OF MEXICO.

THE CARIBBEAN SEA...
UPPER LEVEL CYCLONIC FLOW HAS BEEN PULLING AWAY FROM THE AREA OF
CENTRAL AMERICA...FROM THE BORDER OF NORTHWESTERN HONDURAS AND
GUATEMALA NORTHWESTWARD INTO THE SOUTHWESTERN CORNER OF THE GULF
OF MEXICO. UPPER LEVEL CYCLONIC FLOW MOVES FROM 20N80W
SOUTHEASTWARD INTO THE SOUTH CENTRAL AND SOUTHEASTERN SECTIONS
OF THE CARIBBEAN SEA. THE CYCLONIC FLOW IS IN RESPONSE TO THE
MIDDLE LEVEL TO UPPER LEVEL ATLANTIC OCEAN TROUGH THAT HAS BEEN
MAKING ITS WAY ACROSS THE SOUTHERN HALF OF THE BAHAMAS FROM
30N62W IN THE ATLANTIC OCEAN TO 26N67W AND SOUTHWESTWARD.
SCATTERED MODERATE TO STRONG SHOWERS AND THUNDERSTORMS COVER
BELIZE AND THE EAST CENTRAL YUCATAN PENINSULA...TO THE SOUTHEAST
OF THE CYCLONIC FLOW THAT IS PULLING AWAY TO THE NORTHWEST.
STRONG SHOWERS AND THUNDERSTORMS COVER THE AREA FROM 11N TO 13N
BETWEEN 83W AND 85W...IN SOUTHEASTERN NICARAGUA AND COASTAL
WATERS. THE SURFACE PRESSURE GRADIENT IS WEAK WITH ONLY THE
1012 MB ISOBAR CUTTING ACROSS THE AREA FROM THE SOUTHEAST
TO THE NORTHWEST.

THE ATLANTIC OCEAN...
MIDDLE LEVEL TO UPPER LEVEL CYCLONIC FLOW FROM A WELL-
ESTABLISHED TROUGH COVERS THE AREA TO THE WEST OF 55W.
THE TROUGH PASSES THROUGH 30N62W TO 26N67W...SOUTHWESTWARD
ACROSS THE SOUTHERN BAHAMAS INTO THE SOUTH CENTRAL AND
SOUTHEASTERN CARIBBEAN SEA. A SURFACE TROUGH PASSE THROUGH
BERMUDA TO A 1013 MB LOW PRESSURE THAT IS NEAR 29N66W TO
24N70W. SHOWERS AND ISOLATED STRONG THUNDERSTORMS COVER THE
AREA FROM 20N TO 23N BETWEEN 60W AND 72W. MIDDLE LEVEL TO UPPER
LEVEL CYCLONIC FLOW FROM 17N TO 28N BETWEEN 41W AND 54W. TWO
AREAS OF SHOWERS AND THUNDERSTORMS ARE FROM 22N TO 24N BETWEEN
48W AND 50W...AND FROM 26N TO 27N BETWEEN 53W AND 54W.
THE UPPER LEVEL CYCLONIC FLOW THAT REACHES THE SOUTHEASTERN
CORNER OF THE CARIBBEAN SEA EVENTUALLY EXITS THAT AREA AND MOVES
ACROSS THE TOP OF POSSIBLE ITCZ PRECIPITATION THAT GOES FROM
10N TO 14N BETWEEN 55W AND 61W. THE UPPER LEVEL FLOW IS SHEARING
THE TOPS OF THE CLOUDS IN THIS AREA OF PRECIPITATION. A SEPARATE
AREA OF UPPER LEVEL CYCLONIC FLOW IS TO THE NORTH OF 29N
BETWEEN 35W AND 50W WITH AN UPPER LEVEL CYCLONIC CENTER. UPPER
LEVEL CYCLONIC FLOW COVERS THE AREA FROM THE CANARY ISLANDS
NORTHWARD TO THE EAST OF 26W.

$$
MT




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