[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 201756
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST FRI NOV 20 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.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 8N12W 6N25W 7N41W 8N46W 7N59W.
SCATTERED MODERATE CONVECTION IS FROM 3N-8N BETWEEN 20W-36W.
SIMILAR CONVECTION IS FOCUSED ALONG A SURFACE TROUGH EMBEDDED
WITHIN THE ITCZ AXIS AND ANALYZED FROM 11N39W TO 5N45W.  THE
CONVECTION COVERS AN AREA FROM 6N-10N BETWEEN 40W-47W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL SHORTWAVE TROUGH IS PROGRESSING EASTWARD ACROSS
THE TEXAS AND OKLAHOMA PANHANDLE. THIS UPPER TROUGH SUPPORTS A
COLD FRONT MOVING ACROSS EASTERN TEXAS AND IS INDUCING
CYCLOGENESIS ACROSS THE NW GULF WATERS AS A DEVELOPING 1013 MB
LOW IS CENTERED NEAR 27N95W. A WARM FRONT EXTENDS EAST FROM THE
LOW TO 25N91W. LOW-LEVEL CONVERGENCE NEAR AND NORTH OF THE WARM
FRONT ALONG WITH A ZONE OF UPPER LEVEL DIFFLUENCE LOCATED NORTH
OF THE WARM FRONT AND EAST OF THE UPPER LEVEL TROUGH IS
GENERATING NUMEROUS SHOWERS AND TSTMS N OF 26N W OF 91W.
PRIMARILY W-SW ZONAL UPPER LEVEL FLOW IS NOTED ON WATER VAPOR
IMAGERY ACROSS THE REMAINDER OF THE GULF. THIS ALONG WITH A
SURFACE RIDGE EXTENDING FROM THE SE CONUS ACROSS THE EASTERN
GULF AND FLORIDA PENINSULA IS PROVIDING GENERALLY FAIR SKIES E
OF 90W AND ACROSS THE BAY OF CAMPECHE.

CARIBBEAN SEA...
AN UPPER LEVEL RIDGE WITH AXIS EXTENDING FROM CENTRAL AMERICA TO
CUBA AND HISPANIOLA COVERS THE CARIBBEAN W OF 65W. STRONG
SUBSIDENCE IS NOTED ON WATER VAPOR IMAGERY WITH ONLY A FEW
ISOLATED SHOWERS OCCURRING FROM 13N-17N BETWEEN 77W-81W. ALSO...
ISOLATED SHOWERS ARE OCCURRING OVER THE SW CARIBBEAN...WESTERN
PANAMA...AND COSTA RICA S OF 11N W OF 81W. THE REMAINDER OF THE
CARIBBEAN E OF 65W IS UNDER THE INFLUENCE OF AN UPPER LEVEL
TROUGH OVER THE WESTERN TROPICAL ATLC WITH AXIS ALONG 50W. DRY
NW FLOW ALOFT IS OVER PUERTO RICO AND THE LESSER ANTILLES...
HOWEVER...HIGHER VALUES OF TOTAL PRECIPITABLE WATER STRETCH
ACROSS THE EASTERN CARIBBEAN WITH LOW-LEVEL SHOWERS OCCURRING N
OF 16N BETWEEN 65W-70W AND ALSO EAST OF THE LESSER ANTILLES
FROM 10N-16N BETWEEN 53W-61W. THIS INCREASED LOW-LEVEL MOISTURE
FIELD WILL CONTINUE TO PROVIDE POSSIBLE ISOLATED SHOWERS
THROUGHOUT THE AFTERNOON AND EVENING HOURS OVER THE NE CARIBBEAN.

ATLANTIC OCEAN...
AN UPPER LEVEL SHORTWAVE TROUGH LOCATED OVER THE NE CONUS AND
EASTERN CANADA SUPPORTS A DISSIPATING STATIONARY FRONT THAT
PASSES THROUGH 32N76W TO NEAR CAPE CANAVERAL AND INTO THE SE
GULF OF MEXICO. A SURFACE TROUGH EXTENDS FROM A 1014 MB LOW
NEAR 31N75W TO 28N74W ACROSS THE CENTRAL BAHAMAS TO 23N78W WITH
ISOLATED SHOWERS OCCURRING WITHIN 60 NM EITHER SIDE OF THE
SURFACE TROUGH AND STATIONARY FRONT. FARTHER EAST...AN UPPER
LEVEL TROUGH IS ACROSS THE NE NORTH ATLC AND SUPPORTS A
STATIONARY FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N28W AND
EXTENDS W-SW TO A 1016 MB LOW CENTERED NEAR 27N50W. THE
STATIONARY FRONT CONTINUES W-NW FROM THE LOW ALONG 29N60W TO THE
PREVIOUSLY MENTIONED 1014 MB LOW CENTERED NEAR 31N75W IN THE W
ATLC. SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN 120 NM
EITHER SIDE OF THE ENTIRE STATIONARY BOUNDARY. AIDED BY UPPER
LEVEL DIFFLUENCE ALOFT...SCATTERED SHOWERS FOCUSED NEAR THE 1016
MB LOW ARE BEING ENHANCED FROM 23N-30N BETWEEN 40W-52W. A
SURFACE TROUGH IS ANALYZED FROM PUERTO RICO TO 25N63W. SCATTERED
SHOWERS ARE PRIMARILY E OF THE TROUGH FROM 18N-25N BETWEEN
58W-65W. ACROSS THE CENTRAL ATLC...A SURFACE TROUGH EXTENDS FROM
17N40W TO 24N36W AND ANOTHER SURFACE TROUGH IS FROM 18N45W TO
24N44W WITH POSSIBLE ISOLATED SHOWERS N OF 18N TO THE STATIONARY
FRONT BETWEEN 34W-46W.

$$
HUFFMAN





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