[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 301804
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN AUG 30 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 1745 UTC.

...SPECIAL FEATURE...

TROPICAL WAVE EXTENDS FROM 9N47W TO 17N45W WITH AN ASSOCIATED
1007 MB LOW PRESSURE CENTER NEAR 11N46W. THE WAVE WAS MOVING
WEST AT 15 KT AS AVERAGED OVER THE PAST 24 HOURS. VISIBLE
SATELLITE IMAGERY INDICATED A WELL DEFINED CIRCULATION WHICH
STILL APPEARED TO BE ELONGATED ALONG A SSW TO NNE AXIS. BUOY
41041 REPORTED A SHARP WIND SHIFT FROM NE TO SSE AT 1300 UTC
WHICH SUPPORTED THE EXTENSION OF THE WAVE AXIS NORTHWARD.
SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS CONFINED
TO THE W SEMICIRCLE OF THE LOW AND WEST OF THE WAVE AXIS WITHIN
60 NM OF A LINE THROUGH 10N49W-13N49W-15N47W-17N45W. ADDITIONAL
SCATTERED MODERATE TO STRONG CONVECTION WAS NOTED WITHIN THE
AREA FROM 08N TO 12N BETWEEN 50W AND 55W. THE CHANCE FOR THIS
SYSTEM TO BECOME A TROPICAL CYCLONE DURING THE NEXT 48 HOURS HAS
BEEN ELEVATED TO HIGH.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 23W FROM 05N TO 17N...DRIFTING W OVER THE
PAST 12 HOURS. AS NOTED IN THE PREVIOUS DISCUSSION THE LOCATION
OF THE BEST CYCLONIC CURVATURE IN THE LOW CLOUDS REMAINS OVER
THE CAPE VERDE ISLANDS THUS MAKING IT DIFFICULT TO MOVE THE WAVE
PAST THE CAPE VERDE ISLANDS. AN PATCH OF SCATTERED THUNDERSTORMS
WAS INDICATED WITHIN 45-60 NM OF 13.5N23W. ELSEWHERE ISOLATED
MODERATE SHOWERS WERE NOTED FROM 12N TO 16N BETWEEN 20W AND 24W.

TROPICAL WAVE IS ALONG 71W/72W TO THE SOUTH OF 17N MOVING
WESTWARD ABOUT 15 KT. NO DEEP CONVECTIVE PRECIPITATION
ACCOMPANIES THIS WAVE.

...THE ITCZ...

AXIS IS ALONG 9N14W 7N24W 16N40W...THEN CONTINUES FROM 10N47W TO
THE COAST OF GUYANA NEAR 7N59W. THE ONLY CONVECTION ASSOCIATED
WITH THE ITCZ WAS AN AREA OF SCATTERED MODERATE CONVECTION
WITHIN 60 NM EITHER SIDE OF THE AXIS FROM THE AFRICAN COAST TO
16W.

...DISCUSSION...

THE GULF OF MEXICO...
MID TO UPPER LEVEL ANTICYCLONE OVER CENTRAL MEXICO NEAR 19N98W
DOMINATED THE FLOW OVER THE GULF W OF 88W. THIS IS THE SAME
ANTICYCLONE WHICH IS PROVIDING A FAVORABLE ENVIRONMENT FOR THE
INTENSIFICATION OF NOW CATEGORY FOUR HURRICANE JIMENA IN THE
EASTERN PACIFIC OCEAN. UPPER LEVEL DIFLUENT FLOW EXISTED BETWEEN
THE ANTICYCLONE AND A SHORTWAVE TROUGH MOVING THROUGH THE LOWER
MISSISSIPPI VALLEY WAS AIDING IN THE DEVELOPMENT OF SCATTERED
SHOWERS AND THUNDERSTORMS ALONG A SURFACE TROUGH OVER THE FAR W
GULF OF MEXICO ALONG 96W S OF 25N. THE MIDDLE LEVEL TO UPPER
LEVEL FLOW TURNED MORE TO THE SOUTHWEST OVER THE GULF E OF 88W.
THE FLOW WAS MORE CYCLONIC S OF 26N DUE TO THE PRESENCE OF A
SMALL CYCLONIC CIRCULATION OVER THE WESTERN CARIBBEAN SEA.
ELSEWHERE ISOLATED MODERATE SHOWERS AND THUNDERSTORMS WERE NOTED
IN THE NORTHERN GULF WATERS TO THE NORTH OF 28N BETWEEN 90W AND
THE UPPER TEXAS COAST...TO THE SOUTH OF THE STATIONARY FRONT
THAT PASSES THROUGH WESTERN LOUISIANA INTO SOUTH CENTRAL TEXAS.

THE CARIBBEAN SEA...
MIDDLE LEVEL TO UPPER LEVEL FLOW AROUND A CYCLONIC CIRCULATION
CENTER NEAR 17N85W COVERS THE AREA FROM PANAMA TO JUST OFF CUBA
INTO THE FLORIDA STRAITS. NUMEROUS STRONG SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED ON THE SOUTHEASTERN PERIPHERY OF
THE CYCLONIC FLOW TO THE SOUTH OF 12N BETWEEN 78W AND 82W...
REACHING COASTAL WATERS OF COLOMBIA AND PANAMA. ISOLATED
MODERATE SHOWERS ARE ALSO ON THE EASTERN SIDE OF THE
CYCLONIC CENTER...MOVING FROM 18N NORTHWARD TO CUBA BETWEEN
JAMAICA AND THE ISLE OF PINES/THE ISLE OF YOUTH OF CUBA. MIDDLE
LEVEL TO UPPER LEVEL CYCLONIC FLOW FROM AN UPPER LEVEL CYCLONE
IN THE ATLANTIC NEAR 22N67W IS PUSHING ITS WAY SOUTHWARD INTO
THE DRY AIR/SUBSIDENCE OVER THE CARIBBEAN NORTH OF 17N AND EAST
OF 70W.

THE ATLANTIC OCEAN...
MID OCEANIC MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM 31N40W
THROUGH A PAIR OF CYCLONIC CIRCULATIONS LOCATED NEAR 29N51W AND
22N67W. THE LATTER CIRCULATION WAS PUSHING ITS WAY INTO THE
NORTHEASTERN CARIBBEAN SEA TO THE NORTH OF 17N EAST OF 70W.
SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE
ASSOCIATED WITH THE UPPER LOW AND GENERALLY FROM 21N TO 26N
BETWEEN 58W AND 65W. A BROAD AREA OF SOUTHWESTERLY FLOW ALOFT
EXISTED TO THE S AND E OF THE TROUGH NOTED ABOVE AND MAY AFFECT
THE DEVELOPMENT OF THE LOW PRESSURE AREA NEAR 11N46W.

$$
COBB







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