[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 011756
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SUN NOV 01 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.

...SPECIAL FEATURES...
A 999 MB LOW IS CENTERED NEAR 32N53W WITH A STATIONARY FRONT
THAT EXTENDS ALONG 32N48W 23N50W 19N60W TO 24N74W. THE UPPER
LEVEL SUPPORT FOR THIS SYSTEM IS A LARGE UPPER LEVEL LOW
CENTERED NEAR 29N55W. INSTABILITY AND LIFT ASSOCIATED WITH THE
SYSTEM IS GENERATING DISORGANIZED SCATTERED MODERATE CONVECTION
FROM 30N-33N BETWEEN 52W-58W. THE SURFACE LOW HAS A MEDIUM
CHANCE...30 TO 50 PERCENT...OF BECOMING A SUBTROPICAL OR
TROPICAL CYCLONE OVER THE NEXT COUPLE OF DAYS.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 52W S OF 17N MOVING W NEAR 18 KT. THE
WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP LAYERED MOISTURE
THAT EXTENDS BETWEEN THE ITCZ ALONG 10N AND A CENTRAL ATLC LOW
PRESSURE SYSTEM NEAR 32N53W AND THE ASSOCIATED FRONTAL BOUNDARY.
LOW-LEVEL CONVERGENCE NEAR THE WAVE AXIS COUPLED WITH UPPER
LEVEL DIFFLUENCE IS GENERATING SCATTERED MODERATE CONVECTION
OVER AN AREA FROM 7N-20N BETWEEN 47W-55W.

TROPICAL WAVE IS ALONG 70W S OF 15N MOVING W NEAR 12 KT.
REMAINING FAIRLY WEAK ACROSS THE SOUTH CENTRAL CARIBBEAN...A
MOISTURE MAXIMUM IS NOTED ON TOTAL PRECIPITABLE WATER IMAGERY S
OF 15N BETWEEN 67W-73W. ISOLATED SHOWERS ARE WITHIN 90 NM EITHER
SIDE OF A LINE FROM 15N65W TO 12N73W.

TROPICAL WAVE IS ALONG 89W S OF 17N MOVING W NEAR 15 KT. WAVE IS
INLAND ACROSS PORTIONS OF CENTRAL AMERICA WITH SCATTERED SHOWERS
FROM 14N-20N BETWEEN 87W-92W.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 11N16W 7N30W 10N48W 10N53W
10N68W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS FROM 3N-11N BETWEEN 7W-28W. SIMILAR CONVECTION IS
WITHIN 150 NM EITHER SIDE OF THE AXIS BETWEEN 35W-48W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 1500 UTC...A COLD FRONT EXTENDS ACROSS THE FLORIDA
PANHANDLE FROM NEAR MELBOURNE TO PORT CHARLOTTE AND INTO THE
GULF TO 25N85W AND THEN CONTINUING AS A STATIONARY FRONT ALONG
23N90W TO 20N92W AND INLAND OVER SOUTHERN MEXICO. THE FRONT IS
SUPPORTED ALOFT BY AN UPPER LEVEL TROUGH ACROSS THE SE CONUS AND
NW GULF WITH AXIS EXTENDING FROM NORTHERN MISSISSIPPI SW TO NE
MEXICO NEAR 23N100W. LOW-LEVEL CONVERGENCE NEAR AND ALONG THE
FRONT...COUPLED WITH UPPER LEVEL DIFFLUENCE E OF THE UPPER LEVEL
TROUGH IS GENERATING SCATTERED SHOWERS WITHIN 150 NM N OF THE
STATIONARY FRONT AND WITHIN 90 NM S OF THE STATIONARY FRONT.
STRONGER CONVECTION IS OCCURRING OVER THE EASTERN BAY OF
CAMPECHE FROM 19N-22N BETWEEN 90W-95W. STRONG N-NE WINDS ARE N
AND W OF THE FRONT AS A COOL AND DRIER AIRMASS SETTLES IN ACROSS
THE NW GULF WITH STRONG SUBSIDENCE IN THE MIDDLE TO UPPER LEVELS
AS NOTED ON WATER VAPOR IMAGERY FROM THE WESTERN FLORIDA
PANHANDLE TO NE MEXICO NEAR 20N100W. A SURFACE RIDGE BUILDS IN
BEHIND THE FRONT ANCHORED BY A 1024 MB HIGH CENTERED OVER
SOUTHERN ARKANSAS. AS THE FRONT BECOMES MORE DIFFUSE THROUGH
MONDAY...NELY WINDS ARE FORECAST TO CONTINUE ACROSS MUCH OF THE
GULF.

CARIBBEAN SEA...
AN UPPER LEVEL RIDGE IS ACROSS THE YUCATAN PENINSULA AND
PORTIONS OF CENTRAL AMERICA. UPPER LEVEL DIFFLUENT FLOW IS
GENERATING SCATTERED SHOWERS OVER MUCH OF CENTRAL AMERICA SW OF
A LINE FROM 20N89W TO NW COLOMBIA NEAR 11N75W. ISOLATED TSTMS
ARE EMBEDDED WITHIN THIS AREA OVER THE SW CARIBBEAN WATERS S OF
13N. THE REMAINDER UPPER LEVEL PATTERN ACROSS THE CARIBBEAN
BASIN CONSISTS OF UPPER LEVEL TROUGHING THAT STRETCHES FROM THE
LEEWARD ISLANDS WESTWARD ALONG 17N TO JAMAICA AND FINALLY TO
WESTERN CUBA. STRONG SUBSIDENCE IS NOTED ON WATER VAPOR IMAGERY
N OF 16N E OF 83W KEEPING GENERALLY CLEAR SKIES ACROSS THIS
AREA. HOWEVER...A FEW PASSING ISOLATED SHOWERS LINGER IN THE
VICINITY OF THE GREATER ANTILLES. S OF 17N...WESTERLY UPPER
LEVEL FLOW DOMINATES ALOFT PROVIDING SLIGHT ENHANCEMENT OF
ISOLATED SHOWERS ASSOCIATED WITH THE TROPICAL WAVE ALONG 70W.

ATLANTIC OCEAN...
A COLD FRONT EXTENDS ACROSS THE FAR W ATLC FROM THE SOUTH
CAROLINA COAST NEAR 33N79W S-SW TO NEAR MELBOURNE FLORIDA AND
INTO THE EASTERN GULF OF MEXICO. ISOLATED SHOWERS ARE WITHIN 60
NM EITHER SIDE OF THE FRONT. SHIFTING EASTWARD...THE PRIMARY
FOCUS IN THE ATLC WATERS OVERALL IS A 999 MB LOW CENTERED NEAR
32N53W WITH A STATIONARY FRONT THAT EXTENDS ALONG 32N48W 23N50W
19N60W TO 24N74W. THE UPPER LEVEL SUPPORT FOR THIS SYSTEM IS A
LARGE UPPER LOW AND TROUGH CENTERED NEAR 29N55W. A LARGE UPPER
LEVEL RIDGE IS TO THE W ANCHORED OVER THE W ATLC NEAR 31N71W AND
A SECOND UPPER LEVEL RIDGE TO THE E WITH AXIS ALONG 37W FROM 10N
TO BEYOND 32N. THIS SCENARIO IS ADVECTING TROPICAL MOISTURE NE
AND GENERATING A LARGE AREA OF NUMEROUS SHOWERS AND SCATTERED
TSTMS WITHIN 250 NM EITHER SIDE OF A LINE FROM 17N51W TO 32N43W
E OF THE FRONT...WITH WIDELY SCATTERED SHOWERS REMAIN WITHIN 60
NM EITHER SIDE OF THE STATIONARY FRONT W OF 55W. A SURFACE RIDGE
IS OVER THE EASTERN ATLC ANCHORED BY A 1036 MB HIGH NW OF THE
AZORES.

$$
HUFFMAN




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