[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 221750
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU OCT 22 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 ATLANTIC OCEAN TROPICAL WAVE HAS AN ORIENTATION ALONG
18N31W 15N35W 10N37W MOVING WEST 10 TO 15 KT. THE ORIENTATION
OF THIS WAVE AT THIS MAP TIME IS RELATED TO THE VISIBLE
SATELLITE IMAGERY WITH RESPECT TO SOME SMALL CYCLONIC
CIRCULATION CENTERS THAT ARE BELIEVED TO BE ALONG THE WAVE.
STRONG SHOWERS AND THUNDERSTORMS COVER THE AREA FROM 14N TO 19N
BETWEEN 29W AND 31W. ISOLATED MODERATE SHOWERS AND POSSIBLE
THUNDERSTORMS ARE ELSEWHERE FROM 10N TO 20N BETWEEN 28W AND
36W. UPPER LEVEL WINDS ARE CUTTING ACROSS THE AREA OF THIS
WAVE...SHEARING THE CLOUD TOPS OF THE DEEP CONVECTIVE
PRECIPITATION AND DISPLACING THEM TO THE EAST.

A 1010 MB LOW PRESSURE CENTER IS NEAR 14N43W. STRONG SHOWERS
AND THUNDERSTORMS IS FROM 14N TO 15N BETWEEN 41W AND 42W.

...THE ITCZ...

FROM AFRICA NEAR 13N16W TO 9N30W 9N40W 9N52W INTO NORTHEASTERN
VENEZUELA NEAR 9N62W. WIDELY SCATTERED TO SCATTERED MODERATE
SHOWERS/ISOLATED STRONG THUNDERSTORMS ARE FROM 7N TO 10N BETWEEN
THE COAST OF AFRICA AND 15W...FROM 3N TO 7N BETWEEN 20W AND 43W.
ISOLATED MODERATE SHOWERS FROM 9N TO 11N BETWEEN 53W AND 61W.

...DISCUSSION...

THE GULF OF MEXICO...
A DEEP LAYER TROUGH IS DRIVING A COLD FRONT INTO THE NORTHWESTERN
GULF OF MEXICO. THE FRONT JUST ENTERED THE GULF WATERS AS OF THE
22/1500 UTC MAP ANALYSIS. A SURFACE TROUGH RUNS FROM THE MIDDLE
TEXAS COAST TO 24N96W TO THE EASTERN PART OF THE ISTHMUS OF
TEHUANTEPEC 18N93W. STRONG SHOWERS AND THUNDERSTORMS ARE FROM
27N TO 30N BETWEEN 93W AND 94W. THE FORECAST FOR THE FRONT IS
FOR IT TO BECOME DIFFUSE IN THE FAR EASTERN PART OF THE AREA AND
IN FLORIDA ON SUNDAY AND MONDAY. HIGH PRESSURE WILL BUILD QUICKLY
BEHIND THE FRONT...AND THEN HIGH PRESSURE WILL SHIFT TO THE
NORTHEAST OF THE AREA ON SUNDAY AND MONDAY...AS ANOTHER COLD
FRONT MOVES INTO THE FAR NORTHWESTERN GULF AFTER MONDAY.

FROM THE WESTERN ATLANTIC OCEAN INTO THE WESTERN CARIBBEAN SEA...
A MIDDLE LEVEL TO UPPER LEVEL TROUGH EXTENDS FROM A CYCLONIC
CIRCULATION CENTER THAT IS NEAR 26N75W...ACROSS EASTERN CUBA
BETWEEN 76W AND 77W TO A SECOND CYCLONIC CENTER THAT IS NEAR
20N79W...TO CENTRAL NICARAGUA. A 1007 MB LOW PRESSURE CENTER
IS ALONG THE NICARAGUA COAST NEAR 12N83W. DISORGANIZED
CLOUDINESS AND SHOWERS COVER THE AREA FROM 10N TO 16N BETWEEN
75W AND 83W/84W AT THE COAST OF CENTRAL AMERICA. THE CHANCE
OF THIS FEATURE BECOMING A TROPICAL CYCLONE DURING THE NEXT
48 HOURS IS LOW...LESS THAN 30 PERCENT.

THE BAHAMAS AND THE ADJACENT ATLANTIC OCEAN...
CLOUDINESS AND SHOWERS ACROSS SECTIONS OF THE BAHAMAS AND THE
ADJACENT ATLANTIC OCEAN ARE ASSOCIATED WITH AN UPPER LEVEL
TROUGH AND THE REMNANTS OF A COLD FRONT.  UPPER LEVEL WINDS
ARE EXPECTED TO REMAIN UNFAVORABLE FOR SIGNIFICANT DEVELOPMENT
DURING THE NEXT COUPLE OF DAYS WHILE THE SYSTEM DRIFTS WESTWARD.
THE CHANCE THAT THIS SYSTEM MAY BECOME A TROPICAL OR SUBTROPICAL
CYCLONE DURING THE NEXT 48 HOURS IS LOW...LESS THAN 30 PERCENT.

THE REST OF THE CARIBBEAN SEA...
UPPER LEVEL CYCLONIC FLOW THAT IS TO THE EAST OF 65W IS
ASSOCIATED WITH THE TAIL END OF AN ATLANTIC OCEAN TROUGH
THAT IS ALONG 18N44W TO 16N59W TO 12N64W. DRY AIR IN SUBSIDENCE
IS TO THE EAST OF 70W. UPPER LEVEL MOISTURE THAT IS FROM THE
AREA BETWEEN 70W AND THE 26N75W-TO-CENTRAL NICARAGUA TROUGH IS
MOVING EASTWARD CROSSING 70W LITTLE BY LITTLE. A SURFACE TROUGH
IS ALONG 22N67W 17N68W...THROUGH THE MONA PASSAGE. THIS FEATURE
IS WEAKENING WITH TIME. A SECOND SURFACE TROUGH IS ALONG 64W
FROM 20N TO 23N JUST TO THE NORTH OF THE CARIBBEAN SEA.

THE REST OF THE ATLANTIC OCEAN...
A CENTRAL ATLANTIC OCEAN DEEP LAYER TROUGH SUPPORTS A COLD FRONT
THAT PASSES THROUGH 32N45W TO 26N56W. A PRE-FRONTAL TROUGH
PASSES THROUGH 32N39W TO 27N44W TO 23N50W. SCATTERED MODERATE
SHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE WITHIN 30 NM TO
60 NM ON EITHER SIDE OF 27N49W BEYOND 32N44W...AND 22N48W 25N44W
28N39W BEYOND 32N37W.

$$
MT



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