[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 010556
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SAT OCT 31 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0515 UTC.

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 47W TO THE SOUTH OF 16N
MOVING WEST-NORTHWESTWARD 10 TO 15 KT. THIS WAVE IS MOVING
THROUGH THE SOUTH AND SOUTHEAST OF THE ATLANTIC OCEAN DEEP LAYER
TROUGH AND FRONTAL BOUNDARIES. ISOLATED MODERATE SHOWERS FROM
10N TO 16N BETWEEN 37W AND 40W. A SURFACE TROUGH IS ALONG
36W/38W FROM 18N TO 26N DRIFTING WESTWARD. THIS TROUGH
REPRESENTS WHAT USED TO BE THE NORTHERN EXTENSION OF THE 38W
TROPICAL WAVE. THE TROUGH HAS BROKEN AWAY FROM THE TROPICAL
WAVE. ISOLATED MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS ARE
FROM 16N TO 28N BETWEEN 35W AND 38W.

AN EASTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 65W/66W TO THE
SOUTH OF 16N MOVING WESTWARD 10 TO 15 KT. NO ORGANIZED DEEP
CONVECTIVE PRECIPITATION ACCOMPANIES THIS WAVE.

A WESTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 86W/87W TO THE
SOUTH OF 17N MOVING WESTWARD 10 KT. THIS WAVE IS MOVING THROUGH
THE AREA OF THE BELIZE CYCLONIC CENTER.

...THE ITCZ...

12N13W 7N24W 10N43W...INTO NORTHEASTERN VENEZUELA NEAR 10N62W.
STRONG SHOWERS AND THUNDERSTORMS FROM 5N TO 7N BETWEEN 14W AND
22W. ISOLATED MODERATE SHOWERS ARE ELSEWHERE FROM 4N TO 10N
BETWEEN AFRICA AND 60W.

...DISCUSSION...

THE NORTHWESTERN CARIBBEAN SEA INCLUDING SOUTHERN MEXICO AND
THE SOUTHWESTERN GULF OF MEXICO...
THE ONE-TIME HEALTHY LARGE-SCALE UPPER LEVEL CYCLONIC
CIRCULATION CENTER DURING THE LAST FOUR DAYS HAS DIMINISHED IN
SIZE AND INFLUENCE. THE CENTER NOW IS IN SOUTHERN BELIZE. THE
CYCLONIC FLOW AROUND THIS CENTER IS NOW ONLY REMOTELY APPARENT
FROM THE COASTS OF GUATEMALA AND EL SALVADOR TO THE WATERS JUST
TO THE NORTH OF THE YUCATAN PENINSULA BETWEEN 86W AND THE
ISTHMUS OF TEHUANTEPEC. STRONG SHOWERS AND THUNDERSTORMS COVER
THE AREAS FROM THE GULF OF HONDURAS TO THE YUCATAN PENINSULA
COAST NEAR 20N...AND IN THE NORTHERN ISTHMUS OF TEHUANTEPEC OF
MEXICO. THE MEXICO EASTERN PACIFIC OCEAN COAST BETWEEN THE GULF
OF TEHUANTEPEC AND 100W...WHERE STRONG SHOWERS AND THUNDERSTORMS
HAVE BEEN OCCURRING DURING THE LAST SIX HOURS...FINDS ITSELF AT
THE FRINGES OF THE UPPER LEVEL CYCLONIC FLOW FROM THE BELIZE
CYCLONIC CENTER. ISOLATED MODERATE SHOWERS TO LOCALLY STRONG
THUNDERSTORMS COVER PARTS OF CENTRAL AMERICA FROM COSTA RICA
TO HONDURAS...IN AN AREA OF UPPER LEVEL DIFFLUENT WIND FLOW.

THE REST OF THE GULF OF MEXICO...
A COLD FRONT PASSES THROUGH NORTH CENTRAL FLORIDA INTO THE EAST-
CENTRAL GULF OF MEXICO...TO THE SOUTH CENTRAL PART...BECOMING
STATIONARY AND CONTINUING TO THE EASTERN ISTHMUS OF TEHUANTEPEC
OF MEXICO. DRY AIR IN SUBSIDENCE IS TO THE WEST AND NORTHWEST OF
THE LINE FROM THE WESTERN TIP OF THE FLORIDA PANHANDLE TO THE
MEXICO GULF COAST NEAR 21N/22N...AND TO THE EAST OF THE LINE
FROM THE FLORIDA BIG BEND TO THE CENTRAL YUCATAN CHANNEL.
ISOLATED MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS ARE
IN THE GULF OF MEXICO FROM THE SOUTH CENTRAL GULF TO THE
NORTHERN ISTHMUS OF TEHUANTEPEC. GALE FORCE WINDS ARE OBSERVED
TO THE SOUTH OF 21N TO THE WEST OF THE FRONT.

THE REST OF THE CARIBBEAN SEA...
THE GFS MODEL FOR 500 MB SHOWS A NORTHWEST-TO-SOUTHEAST ORIENTED
INVERTED TROUGH FROM NORTHEASTERN NICARAGUA TO THE NORTHERN
COLOMBIA COAST ALONG 74W/75W. SHOWERS AND POSSIBLE THUNDERSTORMS
HAVE BEEN IN THE AREA OF THE 500 MB INVERTED TROUGH SINCE
31/2245 UTC. 500 MB ANTICYCLONIC FLOW AND BROAD 200 MB CYCLONIC
FLOW ON TOP OF THAT...MIXED IN WITH THE DRY AIR IN SUBSIDENCE
FROM 24 HOURS AGO...COVER THE REST OF THE AREA.

THE ATLANTIC OCEAN...
DEEP LAYER CYCLONIC FLOW AROUND A 31N52W CYCLONIC CIRCULATION
CENTER COVERS THE AREA FROM 19N TO 34N BETWEEN 47W AND 64W.
THE TROUGH EVENTUALLY EXTENDS TO THE EASTERN CARIBBEAN SEA NEAR
15N60W. THIS DEEP LAYER TROUGH SUPPORTS THE 1001 MB GALE LOW
PRESSURE CENTER THAT IS NEAR 30N49W. A COLD FRONT EXTENDS FROM
THE GALE CENTER TO 30N46W 25N47W 21N52W. A STATIONARY FRONT
CONTINUES FROM 21N52W TO 19N60W. THE COMPARATIVELY STRONGEST
SHOWERS AND THUNDERSTORMS NOW ARE FROM 15N TO 16N BETWEEN 48W
AND 49W...AND WITHIN A 30 NM RADIUS OF 16N51W. ISOLATED MODERATE
SHOWERS TO LOCALLY STRONG THUNDERSTORMS ARE ELSEWHERE FROM 10N
TO 20N BETWEEN 42W AND 56W...AND TO THE NORTH OF 20N BETWEEN
39W AND 56W.

$$
MT




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