[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 101140
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SAT DEC 10 2011

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1115 UTC.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE GUINEA COAST
NEAR 10N15W CONTINUING SW TO 8N19W. THE ITCZ CONTINUES FROM
8N19W ALONG 5N24W 5N37W 4N49W. SCATTERED MODERATE CONVECTION IS
FROM 3N-5N BETWEEN 14W-35W. ISOLATED MODERATE CONVECTION IS FROM
5N-8N BETWEEN 25W-40W.

...DISCUSSION...

GULF OF MEXICO...
SURFACE RIDGING CONTINUES TO DOMINATE THE GULF OF MEXICO THIS
MORNING AROUND A 1035 MB HIGH OVER CENTRAL MISSOURI. DESPITE THE
HIGH PRESSURE...LOW-LEVEL CLOUDS AND ISOLATED SHOWERS ARE
EMBEDDED WITHIN THE ANTI-CYCLONIC FLOW ESPECIALLY OVER THE ERN
AND FAR WRN GULF NEAR THE COAST OF MEXICO. SURFACE OBSERVATIONS
ARE ALREADY INDICATING WINDS UP TO 20 KTS ACROSS THE BASIN. AS
THE SURFACE HIGH CONTINUES TO SETTLE OVER THE CENTRAL/ERN CONUS
WINDS UP TO 25 KTS ARE EXPECTED WITH HIGHER GUSTS. A SURFACE
TROUGH IS ALSO ANALYZED ALONG THE MEXICAN COAST FROM 27N97W TO
23N98W WHICH IS HELPING SUPPORT THE SHOWER ACTIVITY NEAR IT.
ALOFT...A BROAD UPPER LEVEL TROUGH IS MOVING ACROSS THE BASIN
WITH AXIS FROM THE FLORIDA PANHANDLE TO THE YUCATAN PENINSULA.
WATER VAPOR IMAGERY INDICATES DRY AIR SE OF A LINE FROM CENTRAL
FLORIDA NEAR 27N83W TO THE BAY OF CAMPECHE NEAR 20N96W. TO THE
NW OF THIS LINE...UPPER LEVEL MOISTURE IS PRESENT SUPPORTING
SOME UPPER LEVEL CLOUDS ACROSS THE NRN GULF. EXPECT SURFACE
RIDGING TO REMAIN ACROSS THE BASIN WITH ISOLATED SHOWERS LIKELY
OVER THE FAR WRN AND ERN PORTIONS OF THE GULF.

CARIBBEAN SEA...
DRY AIR ALOFT OVER THE NW CARIBBEAN IS MAINTAINING MOSTLY FAIR
WEATHER EXCEPT FOR AN AREA OF SCATTERED SHOWERS NEAR A SHEAR
AXIS EXTENDING FROM 20N83W TO 16N84W. THE AXIS DEPICTS THE
DELINEATION BETWEEN 20 KT NLY WINDS TO THE W AND 10 KT NELY
WINDS TO THE E. THIS IS CREATING CONVERGENCE ALONG THE AXIS AND
SUPPORTING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 125
NM W OF THE AXIS. AN AREA OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS IS ALSO FROM 9N-12N BETWEEN 77W-80W WITH ISOLATED
SHOWERS ELSEWHERE S OF 17N BETWEEN 71W-83W DUE TO BROAD CYCLONIC
FLOW AROUND THE MONSOON TROUGH AXIS EXTENDING ACROSS PANAMA TO
NRN COLOMBIA. SHOWERS/THUNDERSTORMS ARE ALSO IMPACTING PUERTO
RICO AND THE NRN-MOST LEEWARD ISLANDS DUE TO ANOTHER SHEAR AXIS
IN THE ATLC THAT EXTENDS JUST S OF THE ISLANDS ALONG 18N BETWEEN
62W-66W. NELY WINDS OF 25 KTS ARE NOTED TO THE N OF THE AXIS
WHILE 5-10 KT WINDS ARE TO THE S. MOST CONDITIONS ARE EXPECTED
TO REMAIN OVER THIS PORTION OF THE BASIN FOR AT LEAST THE NEXT
24 HOURS. THE REMAINDER OF THE BASIN IS UNDER MOSTLY FAIR
CONDITIONS WITH 15-20 KT NE-E TRADEWIND FLOW.

ATLANTIC OCEAN...
A SURFACE TROUGH CONTINUES TO IMPACT THE WRN ATLC ALONG 31N75W
TO 26N80W. SCATTERED SHOWERS ARE WITHIN 75 NM NW OF THE AXIS.
ALOFT...AN UPPER LEVEL RIDGE DOMINATES THE WRN ATLC CENTERED
NEAR 29N62W PROVIDING MOSTLY FAIR WEATHER BESIDES THAT NEAR THE
SURFACE TROUGH. FARTHER E...AN UPPER LEVEL LOW IS IMPACTING THE
CENTRAL ATLC CENTERED NEAR 23N49W. IT IS SUPPORTING A SURFACE
TROUGH ALONG 24N49W 18N50W 17N54W CONTINUING AS A SHEAR AXIS TO
THE NRN LEEWARD ISLANDS ALONG 18N61W TO 18N66W. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE MAINLY E OF THE TROUGH AXIS
WITHIN 300 NM...AND WITHIN 45 NM EITHER SIDE OF THE SHEAR AXIS.
GALE FORCE WINDS ARE ALSO NOTED NE OF THE TROUGH AXIS NEAR
26N47W. MOISTURE NEAR THE UPPER LOW IS ALSO BEING DRAWN ACROSS
THE ERN ATLC TO NRN AFRICA IN WLY FLOW AROUND A NARROW UPPER
LEVEL TROUGH EXTENDING FROM THE UPPER LOW TO S OF THE MADEIRA
ISLANDS AND ACROSS WRN SPAIN. TO THE S...AN UPPER LEVEL RIDGE
DOMINATES THE TROPICAL ATLC SUPPORTING A 1032 MB HIGH CENTERED
NEAR 37N37W WHICH IS COVERING THE REMAINDER OF THE ERN ATLC .
EXPECT THE TROUGH IN THE CENTRAL ATLC TO DRIFT WWD OVER THE NEXT
COUPLE OF DAYS WHILE THE TROUGH IN THE WRN ATLC GRADUALLY
DISSIPATES.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
WALTON





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