[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 311100
TWDAT

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

...TROPICAL WAVES...

AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 38W TO THE SOUTH OF
16N MOVING WEST-NORTHWESTWARD 10 KT. 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 62W TO THE
SOUTH OF 19N MOVING WESTWARD 10 TO 15 KT. THIS WAVE IS MOVING
THROUGH THE AREA OF AN ALREADY-EXISTING UPPER LEVEL TROUGH THAT
EXTENDS FROM 18N56W TO 16N61W TO A 14N65W CYCLONIC CENTER. IT
APPEARS THAT THE NEARBY PRECIPITATION IS RELATED TO THE TROUGH
MORE THAN IT MAY BE ASSOCIATED WITH THE WAVE.

A WESTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 81W/82W TO THE
SOUTH OF 18N MOVING WESTWARD 10 KT. THIS WAVE IS MOVING THROUGH
THE FRINGES OF THE CYCLONIC FLOW THAT IS ASSOCIATED WITH THE
SOUTHERN GUATEMALA UPPER LEVEL CYCLONIC CIRCULATION CENTER.
THE PRECIPITATION THAT IS TO THE EAST OF NICARAGUA AND HONDURAS
PROBABLY IS RELATED TO THE UPPER LEVEL CYCLONIC CENTER.

...THE ITCZ...

12N16W 7N26W 8N37W 7N50W 8N60W. STRONG SHOWERS AND THUNDERSTORMS
FROM 7N TO 8N BETWEEN 56W AND 58W...WITHIN A 30 NM RADIUS OF
7N27.5W. ISOLATED MODERATE SHOWERS AND TO LOCALLY STRONG
THUNDERSTORMS ARE FROM 4N TO 10N BETWEEN AFRICA AND SOUTH
AMERICA...AND FROM 12N TO 14N BETWEEN 40W AND 46W.

...DISCUSSION...

THE CARIBBEAN SEA INCLUDING SOUTHERN MEXICO AND
THE SOUTHWESTERN GULF OF MEXICO...
THE LARGE-SCALE UPPER LEVEL CYCLONIC CIRCULATION CENTER THAT HAS
BEEN MOVING ACROSS THE CARIBBEAN SEA DURING THE LAST THREE DAYS
NOW IS SPINNING THROUGH THE NORTHERN PARTS OF CENTRAL AMERICA.
THE CENTER ACTUALLY IS IN SOUTHERN GUATEMALA. CYCLONIC FLOW
COVERS THE AREA THE EASTERN PACIFIC OCEAN NEAR 10N INTO THE
GULF OF MEXICO JUST TO THE NORTH OF THE YUCATAN PENINSULA NEAR
24N BETWEEN 83W IN THE CARIBBEAN SEA AND 98W IN MEXICO. THIS
AREA ENCOMPASSES PARTS OF THE SOUTHWESTERN GULF OF MEXICO...THE
WESTERN CARIBBEAN SEA...AND INTERIOR MEXICO AND CENTRAL AMERICA.
ISOLATED TO WIDELY SCATTERED MODERATE SHOWERS AND LOCALLY STRONG
THUNDERSTORMS ARE WITHIN 60 NM ON EITHER SIDE OF THE LINE FROM
THE COLOMBIA COAST NEAR 11N75W TO 16N82W TO THE NORTHWESTERN
CORNER OF THE YUCATAN PENINSULA...AND TO THE SOUTH OF 26N BETWEEN
90W IN THE GULF OF MEXICO AND 100W IN MEXICO.

THE REST OF THE GULF OF MEXICO...
A COLD FRONT PASSES THROUGH SOUTHWESTERN ALABAMA TO THE NORTH
CENTRAL GULF WATERS TO THE WESTERN ISTHMUS OF TEHUANTEPEC OF
MEXICO. SOME OF THE PRECIPITATION AROUND THE SOUTHERN HONDURAS
UPPER LEVEL CYCLONIC CENTER MAY BE RELATED TO THE FRONT ALSO.
GALE FORCE WINDS ARE FORECAST TO DEVELOP DURING THE NEXT
24 HOURS IN THE SOUTHWESTERN CORNER OF THE GULF OF MEXICO BEHIND
THE FRONT. THE UPPER LEVEL TROUGH THAT SUPPORTS THIS COLD FRONT
PASSES THROUGH NORTHEASTERN TEXAS TO SOUTH TEXAS/NORTHEASTERN
MEXICO.

THE REST OF THE CARIBBEAN SEA...
DRY AIR IN SUBSIDENCE HAS PUSHED INTO AREA...TO THE NORTHEAST
AND EAST OF THE LINE FROM THE NORTHEASTERN CORNER OF THE YUCATAN
PENINSULA TO THE PENINSULA DE PARAGUANA IN NORTHWESTERN VENEZUELA
NEAR 12N70W. A SEPARATE UPPER LEVEL TROUGH EXTENDS FROM THE
ATLANTIC OCEAN NEAR 18N56W TO 16N61W TO A 14N65W CYCLONIC
CENTER. ISOLATED MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS
ARE WITHIN 30 NM ON EITHER SIDE OF 18N56W 16N61W 15N66W.
THE SEPARATE UPPER LEVEL CYCLONIC CIRCULATION CENTER THAT WAS
NEAR 20N69W ABOUT SIX HOURS AGO APPEARS TO HAVE WEAKENED.

THE ATLANTIC OCEAN...
A DEEP LAYER TROUGH EXTENDS FROM A 32N52W CYCLONIC CENTER TO
25N55W AND 20N56W. THIS DEEP LAYER TROUGH HAS BEEN SUPPORTING
THE COLD FRONT THAT NOW IS ALONG 31N44W 25N50W 21N60W 21N70W...
ACROSS THE BAHAMAS...TO THE FLORIDA COAST NEAR 26N80W. THE DEEP
LAYER TROUGH HAS BEEN DROPPING TO THE SOUTH OF 30N WITH TIME.
DRY AIR IN SUBSIDENCE HAS BEEN MOVING SOUTHWARD WITH THE TROUGH
AND NOW IT COVERS THE AREA TO THE WEST OF 55W. SHOWERS AND
THUNDERSTORMS ARE WITHIN 30 NM ON EITHER SIDE OF 32N43W 27N47W
21N55W. OTHER SHOWERS AND POSSIBLE THUNDERSTORMS ARE ELSEWHERE
TO THE NORTH OF 20N BETWEEN 37W AND 55W.

$$
MT



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