[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 252341
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SUN DEC 25 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 08N13W TO
08N16W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
08N16W TO 04N30W TO 03N43W. SCATTERED MODERATE CONVECTION IS
FROM 03N-08N BETWEEN 30W-36W.

...DISCUSSION...

GULF OF MEXICO...
SOUTHWESTERLY UPPER LEVEL FLOW IS NOTED ACROSS THE ENTIRE GULF
THIS EVENING BETWEEN A BROAD UPPER LEVEL RIDGE OVER THE
CARIBBEAN SEA AND SW NORTH ATLC...AND AN UPPER LEVEL LOW AND
ASSOCIATED TROUGHING CENTERED OVER SE NEW MEXICO NEAR 33N105W.
THIS UPPER LEVEL FLOW PATTERN CONTINUES TO ADVECT MIDDLE TO
UPPER LEVEL MOISTURE NORTHEASTWARD ACROSS MUCH OF THE GULF. WITH
LITTLE MOVEMENT OF THE UPPER LEVEL FEATURES OVER THE PAST 24
HOURS...A WEAK 1020 LOW CENTERED IN THE NW GULF NEAR 28N92W
CONTINUES TO DRIFT SLOWLY N-NW TOWARDS THE LOUISIANA COAST. A
COLD FRONT EXTENDS SOUTHWARD FROM THE LOW TO 23N93W WHERE IT
BECOMES STATIONARY TO THE MEXICO COAST NEAR 18N94W. ISOLATED
SHOWERS ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THE FRONT. A
WARM FRONT IS ANALYZED EAST OF THE LOW CENTER TO THE BIG REGION
OF FLORIDA NEAR 30N83W. MOSAIC DOPPLER RADAR INDICATES SCATTERED
SHOWERS ARE OCCURRING N OF A LINE FROM THE COLD FRONT NEAR
25N93W TO 29N83W. MORE NUMEROUS SHOWER ACTIVITY SPREADS
NORTHWARD OVER THE INTERIOR SE CONUS. WEST OF THE FRONT ALONG
93W...STRONG N-NW WINDS IN THE RANGE OF 20 TO 30 KT ARE FORECAST
TO CONTINUE THROUGH THE OVERNIGHT HOURS AND GRADUALLY DECREASE
THROUGH MONDAY INTO TUESDAY AS HIGH PRESSURE ANCHORED OVER
EASTERN TEXAS BUILDS IN ACROSS THE WESTERN GULF.

CARIBBEAN SEA...
AN UPPER LEVEL RIDGE EXTENDS ACROSS THE CARIBBEAN SEA WITH AXIS
FROM NORTH-CENTRAL VENEZUELA NEAR NEAR 10N66W NW TO THE YUCATAN
CHANNEL NEAR 22N85W. WATER VAPOR IMAGERY INDICATES DRY AIR AND
SUBSIDENCE OVER MUCH OF THE BASIN WITH THE EXCEPTION OF SOME
MIDDLE TO UPPER LEVEL CLOUDINESS OVER THE NW CARIBBEAN AND
YUCATAN PENINSULA. OTHERWISE...FRESH TO STRONG E-NE TRADES
CONTINUE ACROSS MUCH OF THE BASIN THIS EVENING WITH GENERALLY
FAIR SKIES. THESE CONDITIONS ARE EXPECTED TO PERSIST THROUGH
LATE MONDAY. ALSO...LOW-LEVEL CONVERGENCE OF THE TRADES ACROSS
THE WESTERN CARIBBEAN IS GENERATING A FEW ISOLATED SHOWERS OVER
INTERIOR PORTIONS OF CENTRAL AMERICA FROM COSTA RICA NORTHWARD
TO BELIZE AND GUATEMALA.

ATLANTIC OCEAN...
AN UPPER LEVEL RIDGE IS ACROSS MUCH OF THE WESTERN ATLC W OF 50W
AND SUPPORTS SURFACE RIDGING BUILDING IN AS A 1026 MB HIGH
CENTERED OFF THE CAROLINA COAST NEAR 34N73W IS FORECAST TO MOVE
SOUTHEASTWARD. SLICING THROUGH THE RIDGE HOWEVER IS A WEAKENING
COLD FRONT ANALYZED FROM 32N55W TO 29N60W TO 28N68W WHERE
LOW-LEVEL MOISTURE BECOMES MORE DIFFUSE AND A DISSIPATING
STATIONARY FRONT EXTENDS TO THE W-NW TO 29N79W. THE REMAINING
LOW-LEVEL MOISTURE IS GENERATING POSSIBLE ISOLATED SHOWERS
WITHIN 90 NM EITHER SIDE OF THE FRONT. FARTHER EAST...AN UPPER
LEVEL LOW IS CENTERED NEAR 21N41W AND THE ASSOCIATED TROUGH AXIS
EXTENDS ALONG 41W TO 12N. A SURFACE TROUGH IS ANALYZED FROM
10N48W TO 19N42W AND GENERALLY DELINEATES BETWEEN STRONGER E-NE
TRADES TO THE EAST OF THE AXIS AND A SIGNIFICANT AMOUNT OF
MOISTURE AND PRECIPITATION DUE TO STRONG MIDDLE TO UPPER LEVEL
DIFFLUENCE. THE SCATTERED SHOWERS AND ISOLATED TSTMS ARE
OCCURRING FROM 08N-25N BETWEEN 21W-40W. THE REMAINDER OF THE
EASTERN ATLC N OF 25N IS UNDER THE INFLUENCE OF A SURFACE RIDGE
WITH AXIS EXTENDING FROM 42N15W TO 27N35W.

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

$$
HUFFMAN




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