[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 171154
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST TUE NOV 17 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
1115 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N14W 6N30W 8N46W 8N50W 8N61W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 175 NM
EITHER SIDE OF THE AXIS BETWEEN 13W-30W. WIDELY SCATTERED
MODERATE CONVECTION IS FROM 4N-12N BETWEEN 30W-42W. A SURFACE
TROUGH EXTENDS FROM 7N47W TO 14N51W WITH SCATTERED SHOWERS
WITHIN 200 NM EITHER SIDE OF THE TROUGH AXIS.

...DISCUSSION...

GULF OF MEXICO...
AS OF 0900 UTC...A COLD FRONT EXTENDS INTO THE GULF NEAR MOBILE
ALABAMA CONTINUING ALONG 25N90W 21N94W AND INLAND OVER SOUTHERN
MEXICO NEAR 19N95W. ISOLATED SHOWERS ARE WITHIN 60 NM EITHER
SIDE OF THE FRONT. THE COLD FRONT IS SUPPORTED ALOFT BY AN UPPER
LEVEL LOW POSITIONED ACROSS THE CENTRAL AND SOUTHERN U.S. PLAINS
WITH A TROUGH AXIS EXTENDING FROM ARKANSAS THROUGH EASTERN TEXAS
TO NORTHERN MEXICO. STRONG NLY WINDS ARE OBSERVED BEHIND THE
FRONT UP TO 30 KT THIS MORNING WITH GALE CONDITIONS EXPECTED
BEHIND THE FRONT LATER TODAY S OF 21N W OF 95W. THE REMAINDER OF
THE GULF IS INFLUENCED BY A WEAKENING SURFACE RIDGE ACROSS THE
NE GULF OF MEXICO ANCHORED BY A 1017 MB HIGH CENTERED NEAR
28N86W. THE SURFACE RIDGE IS PROVIDING GENERALLY FAIR WEATHER E
OF 87W AND IS ENHANCED BY AN UPPER LEVEL RIDGE THAT EXTENDS FROM
THE YUCATAN CHANNEL OVER THE SOUTHERN FLORIDA PENINSULA AND INTO
THE W ATLC.

CARIBBEAN SEA...
MUCH OF THE CARIBBEAN SEA W OF 65W IS UNDER THE INFLUENCE OF DRY
AND STABLE W-NW FLOW ALOFT WHICH IS PROVIDING GENERALLY FAIR
SKIES AND A LACK OF ANY DEEP CONVECTION. AN UPPER LEVEL RIDGE
EXTENDS FROM THE E PACIFIC REGION ACROSS CENTRAL AMERICA NE OVER
THE YUCATAN PENINSULA AND FLORIDA PENINSULA AS WELL AS E ALONG
15N TO 65W. A FEW ISOLATED SHOWERS AND TSTMS HOWEVER ARE LOCATED
IN THE SW CARIBBEAN S OF 15N BETWEEN 75W-84W DUE IN PART TO
UPPER LEVEL DIFFLUENCE. AN UPPER LEVEL TROUGH WITH AXIS FROM THE
LEEWARD ISLANDS TO NORTHERN VENEZUELA NEAR 10N65W IS GENERATING
SCATTERED SHOWERS NE OF A LINE FROM MARTINIQUE TO S/CENTRAL
HISPANIOLA NEAR 17N71W. THIS SHOWER ACTIVITY SPREADS EAST OF THE
LESSER ANTILLES TO 57W IN THE TROPICAL NORTH ATLC.

ATLANTIC OCEAN...
A SURFACE RIDGE RESIDES ACROSS THE W ATLC W OF 70W AND ACROSS
THE FLORIDA PENINSULA INTO THE NE GULF OF MEXICO. GENERALLY
LIGHT NE WINDS ARE OBSERVED ACROSS THE BAHAMAS AND W ATLC WATERS
THIS MORNING. FARTHER EAST...A 1008 MB LOW IS CENTERED NEAR
26N67W WITH A SURFACE TROUGH EXTENDING S-SW ALONG 23N68W TO OVER
N/CENTRAL HISPANIOLA NEAR 20N71W. ANOTHER SURFACE TROUGH IS
ANALYZED E OF THE LOW CENTER FROM 27N64W ALONG 22N64W TO THE
MONA PASSAGE. THE LOW AND SURFACE TROUGHS ARE SUPPORTED ALOFT BY
AN UPPER LEVEL LOW CENTERED NEAR 26N65W AND AN ASSOCIATED UPPER
LEVEL TROUGH AXIS THAT EXTENDS S-SE TO THE LEEWARD ISLANDS AND
ACROSS THE FAR EASTERN CARIBBEAN SEA. LOW-LEVEL CONVERGENCE NEAR
THE EASTERN-MOST SURFACE TROUGH COUPLED WITH UPPER LEVEL
DIFFLUENCE E OF THE UPPER LEVEL TROUGH AXIS IS GENERATING AN
AREA OF SCATTERED SHOWERS AND TSTMS COVERING A LARGE SWATH OF
THE SW NORTH ATLC AND THE TROPICAL NORTH ATLC FROM 16N-29N
BETWEEN 57W-65W. ACROSS THE CENTRAL AND EASTERN ATLC...A BROAD
SURFACE RIDGE EXTENDS FROM A 1028 MB HIGH CENTERED NEAR 34N34W.
A DISSIPATING COLD FRONT PROTRUDES INTO THE RIDGE ENTERING THE
DISCUSSION AREA NEAR 32N10W CONTINUING SW ALONG 24N20W 20N32W
THEN W AS A DISSIPATING STATIONARY FRONT TO 21N44W. POSSIBLE
ISOLATED SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE FRONT E OF
44W. HOWEVER...SCATTERED SHOWERS AND TSTMS ARE ASSOCIATED WITH A
MORE ACTIVE PORTION OF THE STATIONARY FRONT THAT EXTENDS FROM
21N44W TO 31N52W AND ARE LOCATED WITHIN 120 NM EITHER SIDE OF
THE FRONT. THIS ACTIVITY IS BEING ENHANCED BY AN UPPER LEVEL
DIFFLUENT ENVIRONMENT ALOFT DUE TO AN UPPER LEVEL RIDGE OVER THE
CENTRAL ATLC WITH AXIS ALONG 48W. THE OVERALL DISSIPATING
PORTION OF THE FRONTAL STRUCTURE IS SUPPORTED BY AN UPPER LEVEL
TROUGH ACROSS THE EASTERN ATLC WITH AXIS EXTENDING FROM THE
MADEIRA ISLANDS SW THROUGH THE CANARY ISLANDS TO 13N40W.

$$
HUFFMAN



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