[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 131735
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST FRI NOV 13 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
1700 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 7N10W 6N20W 6N30W 8N38W 6N48W
7N60W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM
4N-7N BETWEEN 9W-14W. SIMILAR ACTIVITY IS FROM 4N-12N BETWEEN
17W-21W...AND FROM 9N-12N BETWEEN 21W-27W. AN EMBEDDED SURFACE
TROUGH IS ANALYZED FROM 12N34W TO 7N37W. SHOWER ACTIVITY IS
SHEARED TO THE E OF THE TROUGH AXIS. SCATTERED MODERATE
CONVECTION IS FROM 7N-14N BETWEEN 44W-54W.

...DISCUSSION...

GULF OF MEXICO...
A SURFACE RIDGE CONTINUES TO BUILD ACROSS THE GULF OF MEXICO
FROM THE N ANCHORED BY A 1016 MB HIGH OVER W MISSISSIPPI NEAR
32N91W PROVIDING GENERALLY FAIR WEATHER ACROSS THE BASIN. MAINLY
LIGHT NLY SURFACE WINDS COVER THE AREA E OF 91W. IN THE UPPER
LEVELS...A NARROW SHORTWAVE TROUGH EXTENDS FROM S FLORIDA TO THE
BAY OF CAMPECHE INTO CENTRAL MEXICO. SIGNIFICANT DRY AIR AND
SUBSIDENCE IS OVER MUCH OF THE BASIN OBSERVED IN WATER VAPOR
IMAGERY PROVIDING STABLE CONDITIONS TO THE AREA. AREAS OF
STRATOCUMULUS CLOUDS ARE ALSO OVER MUCH OF THE BASIN NOTED ON
VISIBLE SATELLITE IMAGERY. EXPECT THE SURFACE RIDGE TO DRIFT E
AS SE RETURN FLOW DEVELOPS OVER THE WRN GULF AHEAD OF THE NEXT
COLD FRONT EXPECTED TO MOVE OFF THE TEXAS COAST MON AFTERNOON.

CARIBBEAN SEA...
AS OF 1500 UTC...A STATIONARY FRONT EXTENDS FROM THE W ATLC
ACROSS ERN CUBA NEAR 21N77W INTO THE NW CARIBBEAN TO 19N81W. A
PRE-FRONTAL SURFACE TROUGH SE OF THE FRONT EXTENDS FROM 21N76W
TO 16N79W. ISOLATED SHOWERS/THUNDERSTORMS ARE WITHIN 100 NM SE
OF THE TROUGH AXIS. AN UPPER LEVEL TROUGH CENTERED OFF THE COAST
OF VIRGINIA SUPPORTS THE FRONT AND SURFACE TROUGH. SCATTERED
SHOWERS/THUNDERSTORMS ARE OVER THE SW CARIBBEAN S OF 11N BETWEEN
76W-84W IN ASSOCIATION WITH SURFACE CONVERGENCE NEAR THE E
PACIFIC ITCZ. A BROAD UPPER LEVEL RIDGE COVERS THE MAJORITY OF
THE CARIBBEAN ALONG WITH MODERATELY DRY AIR ALOFT BESIDES A
SWATH OF UPPER LEVEL MOISTURE NEAR THE FRONTAL SYSTEM. NW TO N
WINDS OF 20-25 KT TRAIL BEHIND THE FRONT REACHING 30 KT NEAR THE
COAST OF NICARAGUA. MODERATE TRADE WINDS PREVAIL ACROSS THE ERN
CARIBBEAN.

ATLANTIC OCEAN...
AS OF 1500 UTC...A STATIONARY FRONT ENTERS THE DISCUSSION AREA
NEAR 32N70W ALONG 26N73W ACROSS THE CENTRAL BAHAMAS TO ERN CUBA
NEAR 21N77W. A PRE-FRONTAL SURFACE TROUGH IS ANALYZED TO THE E
ALONG 31N68W 26N71W ACROSS THE ERN BAHAMAS TO ERN CUBA NEAR
21N76W. SCATTERED SHOWERS/THUNDERSTORMS ARE TO THE E OF THE
TROUGH FROM 23N-32N BETWEEN 63W-68W. THE FRONT/TROUGH ARE
SUPPORTED BY AN UPPER LEVEL TROUGH COVERING THE W ATLC CENTERED
OFF THE COAST OF VIRGINIA NEAR 34N74W. UPPER LEVEL DIFFLUENCE
BETWEEN THIS UPPER TROUGH AND AN UPPER LEVEL RIDGE TO THE W
EXTENDING FROM THE LEEWARD ISLANDS TO NEAR 29N53W IS SUPPORTING
THE SHOWER ACTIVITY E OF THE TROUGH AXIS. THIS UPPER DIFFLUENT
ZONE IS ALSO SUPPORTING ISOLATED SHOWERS/THUNDERSTORMS FROM
19N-29N BETWEEN 56W-69W. TO THE E...A COLD FRONT BRUSHES THE NRN
BORDER OF THE DISCUSSION AREA FROM A 1009 MB LOW NEAR 32N35W
ALONG 30N42W TO 32N52W. ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS
ARE WITHIN 100 NM OF THE FRONT AXIS. THE FRONT IS SUPPORTED BY A
SHORTWAVE UPPER TROUGH WITH AXIS ALONG 48W. A BROAD SURFACE
RIDGE DOMINATES THE REMAINDER OF THE ERN ATLC ANCHORED BY A 1020
MB HIGH NEAR 26N31W. IN THE UPPER LEVELS...A BROAD UPPER RIDGE
COVERS THE TROPICAL ATLC WHILE A SHORTWAVE UPPER LEVEL TROUGH
EXTENDS FROM S OF THE CANARY ISLANDS TO W OF THE CAPE VERDE
ISLANDS. THIS UPPER LEVEL TROUGH IS SHEARING MOISTURE FROM THE
ITCZ TO THE NE SUPPORTING CLOUDINESS AND POSSIBLE ISOLATED
SHOWERS SE OF A LINE FROM 12N30W TO 20N16W.


A COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N72W AND EXTENDS
S-SW ALONG 30N72W TO THE SE BAHAMAS NEAR 24N75W TO EASTERN CUBA
AND INTO THE NW CARIBBEAN. POSSIBLE ISOLATED SHOWERS ARE WITHIN
60 NM EITHER SIDE OF THE FRONT. E OF THE FRONT...A SURFACE
TROUGH IS ANALYZED FROM 31N70W TO 25N72W AND OVER EASTERN CUBA.
SCATTERED SHOWERS AND TSTMS ARE OCCURRING WITHIN 60 NM EITHER
SIDE OF THE SURFACE TROUGH WITH ENHANCED CONVECTION N OF 25N
BETWEEN 65W-70W. THIS FRONT IS BEING DRIVEN BY AN UPPER LEVEL
LOW CENTERED OFF THE NORTH CAROLINA COAST NEAR 34N75W AND UPPER
LEVEL TROUGHING DIPPING TO 25N W OF 69W. UPPER LEVEL DIFFLUENCE
E OF THE UPPER TROUGH AXIS IS ALSO AIDING IN ENHANCING THE
CONVECTION. FARTHER E...A 1003 MB LOW IS CENTERED NEAR 33N62W.
LOW-LEVEL CONVERGENCE EAST OF THE LOW CENTER FOCUSED ON A
WEAKENING STATIONARY FRONT EXTENDING FROM THE LOW TO 31N55W IS
GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS N OF 29N BETWEEN
50W-60W. THIS CONVECTION IS BEING ENHANCED BY A LARGE AREA OF
UPPER LEVEL DIFFLUENCE ACROSS THE WESTERN ATLC AND INTO THE
CENTRAL ATLC N OF 24N BETWEEN 50W-70W. OVER THE CENTRAL ATLC...A
COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N38W AND EXTENDS
WESTWARD ALONG 31N TO 53W. ISOLATED SHOWERS AND TSTMS ARE WITHIN
90 NM EITHER SIDE OF THE FRONT. ACROSS THE REMAINDER OF THE
CENTRAL AND EASTERN ATLC...A BROAD SURFACE RIDGE DOMINATES
ANCHORED BY A 1018 MB HIGH CENTERED NEAR 26N31W. THIS SURFACE
HIGH IS SUPPORTED BY A BROAD UPPER LEVEL RIDGE WITH AXIS ALONG
40W. EAST OF THE UPPER LEVEL RIDGE...AN UPPER LEVEL TROUGH AXIS
DIPS SOUTHWARD TO 14N E OF 27W AND CONTINUES SHEARING MOISTURE
FROM THE ITCZ TO THE NE SUPPORTING SCATTERED SHOWERS SE OF A
LINE FROM NORTHERN MAURITANIA NEAR 21N17W TO SW OF THE CAPE
VERDE ISLANDS NEAR 13N27W.

$$
HUFFMAN




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