[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 120555
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST WED DEC 12 2012

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 08N13W TO
07N17W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
07N17W TO 04N38W TO 07N50W TO 06N55W. SCATTERED MODERATE
CONVECTION IS FROM 05N-10N BETWEEN 39W-49W.

...DISCUSSION...

GULF OF MEXICO...
MIDDLE TO UPPER LEVEL SOUTHWESTERLY FLOW DOMINATE OVER THE GULF
THIS EVENING BETWEEN UPPER LEVEL TROUGHING LOCATED OVER THE
CENTRAL CONUS AND AN UPPER LEVEL RIDGE CENTERED NEAR 25N69W OVER
THE SW NORTH ATLC. WITH A MID-LEVEL SHORTWAVE TROUGH AXIS OVER
OKLAHOMA AND TEXAS...THE TROUGHING SUPPORTS A COLD FRONT
ANALYZED FROM NORTHERN FLORIDA NEAR 30N82W TO 26N88W WHICH THEN
BECOMES STATIONARY TO 24N92W TO THE MEXICO COAST NEAR 19N96W.
PLENTY OF MIDDLE TO UPPER LEVEL MOISTURE CONTINUES TO STREAM
E-NE FROM THE PACIFIC REGION OVER CENTRAL MEXICO TO THE SE
CONUS. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING WITHIN
240 NM NORTHWEST OF THE FRONT. OTHERWISE...THE REMAINDER OF THE
GULF IS UNDER THE INFLUENCE OF PRE-FRONTAL SURFACE TROUGHING
WITH A SURFACE TROUGH AXIS ANALYZED FROM 25N84W TO THE YUCATAN
PENINSULA 21N88W. SCATTERED SHOWERS AND TSTMS ARE OCCURRING EAST
OF A LINE FROM 29N83W TO 22N89W. THE FRONTAL BOUNDARY IS
EXPECTED TO INCREASE IN EASTWARD MOVEMENT AS ENERGY ASSOCIATED
WITH THE MID-LEVEL SHORTWAVE TROUGH PROGRESSES EAST OVER THE
NEXT 24 TO 36 HOURS WITH THE FRONT CLEARING THE GULF REGION BY
THURSDAY. HIGH PRESSURE WILL THEN BUILD IN ACROSS THE GULF
WITH PERSISTENT N-NE WINDS.

CARIBBEAN SEA...
MUCH OF THE BASIN IS UNDER FAIRLY TRANQUIL CONDITIONS AS WATER
VAPOR IMAGERY INDICATES AN UPPER LEVEL RIDGE WITH AXIS EXTENDING
FROM THE SW CARIBBEAN NEAR 13N80W TO BEYOND 23N70W IS PROVIDING
A RELATIVELY DRY AND STABLE ATMOSPHERE E OF 85W. A FEW ISOLATED
SHOWERS AND TSTMS ARE HOWEVER OCCURRING OVER PORTIONS OF THE SW
CARIBBEAN S OF 11N DUE TO CLOSE PROXIMITY OF THE MONSOON TROUGH
AXIS WHICH EXTENDS FROM THE EASTERN PACIFIC REGION ALONG 09N TO
NORTHERN COLOMBIA NEAR 08N77W. OTHERWISE...A FEW PASSING LOW-
TOPPED ISOLATED SHOWERS ARE NOTED ON SATELLITE IMAGERY ACROSS
THE NORTH-CENTRAL CARIBBEAN N OF 15N BETWEEN 65W-74W AND THE SE
CARIBBEAN S OF 15N E OF 70W. WHILE CONDITIONS ARE CONVECTIVELY
QUIET...THE EXISTING PRESSURE GRADIENT BETWEEN A STRONG CENTRAL
ATLC RIDGE AND LOWER PRESSURE ACROSS NORTHERN SOUTH AMERICA IS
PROVIDING FOR ENHANCED EASTERLY TRADE WIND FLOW IN THE RANGE OF
20 TO 30 KT. THESE TRADES ARE EXPECTED TO PERSIST THROUGH LATE
THURSDAY.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL RIDGE IS OVER THE SW NORTH ATLC WITH
AXIS EXTENDING FROM THE SW CARIBBEAN SEA NORTHEASTWARD TO BEYOND
32N64W. WATER VAPOR IMAGERY INDICATES FAIRLY DRY AIR REMAINS
EAST OF A LINE FROM 32N68W TO 22N80W...HOWEVER WITH THE PRESENCE
OF A COLD FRONT FROM 32N79W TO 30N81W AND THE APPROACH OF A
FRONTAL TROUGH CURRENTLY OVER THE FLORIDA PENINSULA AND EASTERN
GULF OF MEXICO...SCATTERED SHOWERS AND TSTMS ARE OCCURRING
ACROSS THE FLORIDA PENINSULA AND SW NORTH ATLC WATERS NW OF A
LINE FROM 32N71W TO 24N80W. OTHERWISE...THE REMAINDER OF THE SW
NORTH ATLC AND CENTRAL ATLC ARE UNDER THE INFLUENCE OF A BROAD
RIDGE ANCHORED BY A 1029 MB HIGH AND 1030 MB HIGH CENTERED NEAR
32N53W AND 34N39W RESPECTIVELY. ON THE SOUTHERN PERIPHERY OF THE
RIDGE...AN UPPER LEVEL TROUGH AXIS IS NOTED ON WATER VAPOR
IMAGERY FROM 26N45W TO 16N61W THAT SUPPORTS A SURFACE TROUGH
AXIS ANALYZED FROM 17N44W TO 08N51W. ASIDE FROM LOW-LEVEL
MOISTURE CONVERGENCE...STRONG MIDDLE TO UPPER LEVEL DIFFLUENCE
IS GENERATING SCATTERED SHOWERS AND TSTMS FROM 10N-18N BETWEEN
40W-52W...AND FROM 13N-22N BETWEEN 28W-40W.

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

$$
HUFFMAN



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