[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 021152
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST MON NOV 02 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
1045 UTC.

...SPECIAL FEATURES...
A 1000 MB LOW IS CENTERED NEAR 34N58W. A SURFACE TROUGH EXTENDS
S OF THE LOW ALONG 29N57W 26N59W 24N64W. A DYING STATIONARY
FRONT ALSO ASSOCIATED WITH THE LOW EXTENDS TO THE E  ALONG
41N51W 32N49W 26N50W 21N55W THEN W N OF THE LEEWARD ISLANDS
ALONG 20N64W TO THE BAHAMAS NEAR 22N74W. A LARGE UPPER LOW
CENTERED NEAR 33N55W SUPPORTS THE SYSTEM. SHOWERS/THUNDERSTORM
ACTIVITY NEAR THE CENTER HAS DIMINISHED. HOWEVER...CONVECTION
ALONG THE FRONT REMAINS N OF 17N BETWEEN 45W-54W...BECOMING
STRONG IN SOME AREAS NEAR THE FRONT. IF THE SYSTEM LOSES ITS
FRONTAL PROPERTIES...THEN THE LOW COULD BECOME A SUBTROPICAL OR
TROPICAL SYSTEM. HOWEVER...ATMOSPHERIC CONDITIONS ARE NOT AS
FAVORABLE AS THEY WERE. THE SURFACE LOW HAS A MEDIUM CHANCE...30
TO 50 PERCENT...OF BECOMING A SUBTROPICAL OR TROPICAL CYCLONE
OVER THE NEXT COUPLE OF DAYS AS IT MOVES NW THEN NORTHWARD.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 55W/56W S OF 15N MOVING W NEAR 18 KT. THE
WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN
TOTAL PRECIPITABLE WATER IMAGERY. STRONG SLY FLOW ALOFT
ASSOCIATED WITH THE UPPER LEVEL LOW SUPPORTING THE SURFACE LOW
NEAR 34N58W...SEE SPECIAL FEATURES ABOVE...IS SHEARING MOISTURE
FROM THE TROPICS TO THE N. NO DEEP CONVECTION IS CURRENTLY
ASSOCIATED WITH THE WAVE. HOWEVER...ISOLATED SHOWERS ARE FROM
13N-16N BETWEEN 53W-56W.

TROPICAL WAVE EXTENDS FROM 13N69W TO 6N72W MOVING W NEAR 12 KT.
THE WAVE COINCIDES WITH A LOW-AMPLITUDE DEEP LAYER MOISTURE
MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. NO DEEP
CONVECTION IS CURRENTLY ASSOCIATED WITH THE WAVE.
HOWEVER...ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS ARE E OF THE
WAVE ALONG A LINE FROM 14N68W TO 17N63W.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 12N15W 9N24W 9N40W 12N54W 12N60W
9N67W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM
6N-13N BETWEEN 12W-27W. SCATTERED MODERATE/STRONG CONVECTION IS
FROM 5N-13N BETWEEN 34W-49W. ISOLATED MODERATE/STRONG CONVECTION
IS FROM 11N-13N BETWEEN 59W-64W.

...DISCUSSION...

GULF OF MEXICO...
A STATIONARY FRONT REMAINS ACROSS THE SE GULF EXTENDING FROM
NEAR 25N81W ALONG 24N85W 23N92W BECOMING WARM ALONG 21N94W TO
18N94W. ISOLATED SHOWERS ARE POSSIBLE ALONG THE FRONTAL BOUNDARY
BETWEEN 84W-88W. SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE
BAY OF CAMPECHE FROM 18N-23N BETWEEN 90W-94W. THE FRONT IS
SUPPORTED BY A BROAD UPPER LEVEL TROUGH OVER THE ERN CONUS AND A
SHORTWAVE TROUGH EXTENDING ACROSS TEXAS AND NRN MEXICO TO NEAR
16N100W. AN UPPER LEVEL RIDGE COVERS THE SRN GULF WITH AXIS OVER
THE YUCATAN PENINSULA. MOIST SWLY AND DIFFLUENT FLOW ALOFT
BETWEEN THESE UPPER LEVEL FEATURES IS SUPPORTING THE SHOWER
ACTIVITY IN THE BAY OF CAMPECHE. STRONG DRY AIR AND SUBSIDENCE
COVERS THE NW PORTION OF GULF IN THE WAKE OF THE FRONT ALONG
WITH SURFACE HIGH PRESSURE BUILDING TO THE N. EXPECT THE FRONT
TO DIMINISH LATER TODAY AS HIGH PRESSURE BUILDS BEHIND IT
THROUGHOUT THE WEEK.

CARIBBEAN SEA...
DRY SUBSIDENT AIR DIPS ACROSS THE CARIBBEAN FROM THE N
ASSOCIATED WITH AN UPPER LEVEL RIDGE ACROSS THE WRN ATLC. A FEW
ISOLATED SHOWERS/THUNDERSTORMS ARE N OF HONDURAS FROM 16N-18N
BETWEEN 82W-88W ENHANCED BY DIFFLUENT FLOW ALOFT BETWEEN AN
UPPER LEVEL RIDGE OVER THE YUCATAN PENINSULA AND W TO NW FLOW
ALOFT ACROSS MUCH OF THE BASIN. SCATTERED
SHOWERS/THUNDERSTORMS ARE ALSO ACROSS THE SW BASIN S OF 13N
BETWEEN 76W-84W DUE TO SURFACE CONVERGENCE NEAR THE ITCZ
EXTENDING FROM COLOMBIA NEAR 10N74W TO 11N85W AND INTO THE E
PACIFIC. ISOLATED SHOWERS/THUNDERSTORMS ARE IN THE ERN CARIBBEAN
E OF 69W S OF 17N. SOME OF THESE SHOWERS ARE POSSIBLY SUPPORTED
BY THE TROPICAL WAVE EXTENDING FROM 13N69W TO 6N72W. LIGHT TO
MODERATE TRADE WINDS ARE ACROSS MUCH OF THE BASIN.

ATLANTIC OCEAN...
AS OF 0900 UTC...A STATIONARY FRONT EXTENDS FROM A 1012 MB LOW
OFF THE N CAROLINA COAST NEAR 36N75W ENTERING THE DISCUSSION
AREA NEAR 32N76W EXTENDING TO THE FLORIDA COAST NEAR 27N80W
CONTINUING INTO THE GULF. ISOLATED SHOWERS ARE POSSIBLE ALONG
THE FRONT AXIS. THE FRONT IS SUPPORTED BY A BROAD UPPER LEVEL
TROUGH OVER THE ERN CONUS. AN UPPER LEVEL RIDGE COVERS THE
REMAINDER OF THE WRN ATLC CENTERED NEAR 26N72W PROVIDING DRY AIR
ALOFT. A SURFACE TROUGH EXTENDS ALONG 29N57W 26N59W 24N64W.
ISOLATED SHOWERS ARE ALONG THE FRONT AXIS. A DYING STATIONARY
FRONT EXTENDS TO THE E ASSOCIATED WITH THE LOW NEAR 34N58W
ENTERING THE DISCUSSION AREA NEAR 32N49W CONTINUING S ALONG
26N50W 21N55W THEN W N OF THE LEEWARD ISLANDS ALONG 20N64W TO
THE BAHAMAS NEAR 22N74W. A LARGE AREA OF SHOWERS/THUNDERSTORMS
EXTEND N OF 17N BETWEEN 45W-54W...BECOMING STRONG IN SOME AREAS
NEAR THE FRONT. THE LOW SYSTEM...SURFACE TROUGH...AND FRONT ARE
SUPPORTED BY AN UPPER LEVEL LOW NEAR 33N55W WHICH IS DRAWING UP
MOISTURE FROM THE TROPICS. IF THE SURFACE LOW LOSES ITS FRONTAL
PROPERTIES...IT MAY BECOME A SUBTROPICAL OR TROPICAL SYSTEM. SEE
SPECIAL FEATURES ABOVE. TO THE E...A BROAD SURFACE RIDGE
DOMINATES ANCHORED BY A 1035 MB HIGH N OF THE AREA NEAR 40N31W.
IN THE UPPER LEVELS...A NARROW UPPER LEVEL RIDGE IS WEDGED
BETWEEN THE UPPER LEVEL LOW NEAR 33N55W AND AN UPPER LEVEL
TROUGH COVERING THE ERN ATLC E OF 24W CENTERED OVER AFRICA NEAR
23N15W.

$$
WALTON



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