[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 171720
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1645 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 9N11W 7N25W 5N34W 5N44W 4N55W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 6N-11N
BETWEEN 8N-19N. ISOLATED MODERATE CONVECTION IS WITHIN 90 NM
N...AND 120 NM S OF THE AXIS BETWEEN 19W-26W. A SURFACE TROUGH
IS ANALYZED WITHIN THE ITCZ FROM 12N51W TO 4N46W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 7N-8N BETWEEN
46W-49W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 1500 UTC...A COLD FRONT EXTENDS ACROSS THE FLORIDA
PANHANDLE ENTERING THE GULF OF MEXICO NEAR 30N86W JUST W OF
PANAMA CITY CONTINUING ALONG 25N88W 22N92W TO THE MEXICO COAST
NEAR 18N94W EXTENDING AS A STATIONARY FRONT ALONG 18N96W 21N99W.
A LINE OF SHOWERS IS ALONG THE FRONT AXIS WITH ISOLATED SHOWERS
POSSIBLE WITHIN 100 NM BEHIND THE FRONT N OF 24N...AND WITHIN
150 NM BEHIND THE FRONT S OF 24N. NW TO N SURFACE WINDS OF 20 TO
25 KTS ARE BEHIND THE FRONT...REACHING 30 KT N OF 25N BETWEEN
90W-91W. GALE FORCE WINDS ARE ALSO NOTED IN THE SW GULF S OF 21N
W OF 95W. THE FRONT IS SUPPORTED BY AN UPPER LEVEL TROUGH
DIGGING ACROSS THE CENTRAL CONUS INTO THE NRN GULF CENTERED OVER
MISSOURI. AN UPPER LEVEL RIDGE IS ACROSS THE SRN GULF EXTENDING
FROM THE WRN CARIBBEAN ACROSS S FLORIDA AND INTO THE WRN ATLC.
DRY AIR AND CLEAR SKIES BUILD BEHIND THE FRONT ACROSS THE NW
GULF. MODERATELY DRY AIR AND FAIR WEATHER IS ALSO AHEAD OF THE
FRONT ACROSS THE SE GULF AND S FLORIDA. EXPECT THE FRONT TO
CONTINUE PUSHING E-SE THROUGH WED EVENING BEFORE STALLING AND
WEAKENING OVER N FLORIDA. EXPECT GALE FORCE WINDS TO CONTINUE IN
THE SW GULF OF MEXICO FOR THE NEXT SEVERAL HOURS.

CARIBBEAN SEA...
MUCH OF THE CARIBBEAN IS EXPERIENCING GENERALLY FAIR WEATHER
UNDER THE INFLUENCE OF DRY AIR AND SUBSIDENCE ASSOCIATED WITH AN
UPPER LEVEL RIDGE COVERING THE WRN CARIBBEAN EXTENDING FROM THE
YUCATAN PENINSULA AND WRN CARIBBEAN ACROSS S FLORIDA TO THE WRN
ATLC. ISOLATED SHOWERS/THUNDERSTORMS ARE IN THE SW CARIBBEAN
AFFECTING PORTIONS OF COSTA RICA/PANAMA S OF 11N BETWEEN 77W-84W
DUE TO SURFACE CONVERGENCE NEAR THE E PACIFIC ITCZ. ISOLATED
SHOWERS/THUNDERSTORMS ARE ACROSS THE NE CARIBBEAN AFFECTING
PUERTO RICO AND THE NW LEEWARD ISLANDS N OF 16N BETWEEN 60W-67W
ASSOCIATED WITH SURFACE CONVERGENCE NEAR A SURFACE TROUGH
EXTENDING FROM THE ATLC TO E OF PUERTO RICO NEAR 18N65W. AN
UPPER LEVEL TROUGH EXTENDING FROM THE ATLC SWD ACROSS THE LESSER
ANTILLES SUPPORTS THE SURFACE TROUGH AND PROVIDES AN UPPER
DIFFLUENT ZONE TO ENHANCE THE SHOWER ACTIVITY. MODERATE TO FRESH
TRADE WINDS ARE ACROSS MUCH OF THE BASIN. EXPECT
SHOWERS/THUNDERSTORMS TO CONTINUE OVER THE FAR NE CARIBBEAN AS
THE SURFACE TROUGH REMAINS MAINLY STATIONARY.

ATLANTIC OCEAN...
LOW PRESSURE REMAINS ACROSS THE WRN ATLC CENTERED AT A 1008 MB
LOW NEAR 26N65W. A SURFACE TROUGH EXTENDS FROM THE LOW CENTER
ALONG 22N65W 19N68W. A SECOND SURFACE TROUGH EXTENDS TO THE E
ALONG 27N63W 23N63W TO E OF PUERTO RICO NEAR 18N65W. SCATTERED
SHOWERS/THUNDERSTORMS ARE WITHIN 250 NM E OF THIS TROUGH AXIS.
THIS LARGE AREA OF CONVECTIVE ACTIVITY IS ENHANCED BY DIFFLUENT
FLOW ALOFT BETWEEN AN UPPER LEVEL TROUGH CENTERED NEAR
27N65W...SUPPORTING THE LOW/TROUGHS...AND AN UPPER LEVEL RIDGE
TO THE E WITH AXIS ALONG 48W. ACROSS THE ERN ATLC...A BROAD
SURFACE RIDGE EXTENDS S FROM A 1026 MB HIGH NEAR 33N32W. A
SURFACE TROUGH EXTENDS AROUND THE RIDGE PARALLELING THE ISOBARS
ALONG 31N11W 20N27W 19N36W 22N47W 30N52W...DEPICTING A LINE OF
CONVERGENT WIND SPEEDS...NOT WIND DIRECTION...WITH STRONGER
WINDS TO THE N OF THE AXIS. A LONGWAVE UPPER LEVEL TROUGH
EXTENDING FROM THE NE ATLC ALONG 46N9W TO THE CANARY ISLANDS
NEAR 29N17W ACROSS THE CAPE VERDE ISLANDS NEAR 17N25W TO 12N35W
SUPPORTS THE SURFACE TROUGH. UPPER LEVEL DIFFLUENCE AND STRONG
SHEAR TO THE NE-E BETWEEN AROUND THE BASE OF THIS UPPER TROUGH
IS ENHANCING CONVECTION IN THE ERN TROPICAL ATLC AND NEAR THE
ITCZ. BESIDES THE CONVECTION DISCUSSED IN THE ITCZ
SECTION...SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN A 200 NM
SWATH FROM 10N42W 12N30W 17N17W.

$$
WALTON



This weather bulletin was brought to you by:
www.nashvilleweather.net