[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 291253
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SAT DEC 29 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1045 UTC.

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

MONSOON TROUGH EXTENDS ACROSS WEST AFRICA TO COAST OF LIBERIA
WHERE IT TRANSITIONS INTO ITCZ ALONG 06N10W 03N30W EQ49W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 3N-7N BETWEEN
23W-38W AND FROM EQ-2N BETWEEN 31W-36W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 0900 UTC...A COLD FRONT EXTENDS FROM THE FLORIDA PANHANDLE
NEAR 31N84W TO THE EASTERN COAST OF MEXICO ALONG 24N89W 22N95W
19N96W. STRONG SHOWERS/ISOLATED THUNDERSTORMS ARE UP TO 150 NM
EAST OF THE AXIS NORTH OF 24N. ISOLATED SHOWERS ARE UP TO 120 NM
AHEAD OF THE FRONT ELSEWHERE. STRONG NORTHWEST-NORTH WINDS OF
20-25 KT ARE OBSERVED BEHIND THE FRONT. THE FRONT IS SUPPORTED
BY AN UPPER LEVEL TROUGH MOVING THROUGH THE MISSISSIPPI VALLEY
WITH A SHORTWAVE DIPPING SOUTH OVER ALABAMA AND GEORGIA. BROAD
UPPER RIDGING COVERS THE SOUTHERN GULF ACCOMPANIED BY DRY
AIR...WHICH IS HELPING PROVIDE FAIR CONDITIONS ACROSS THE SE
GULF. THE FRONT IS EXPECTED TO CONTINUE TO PUSH SE ACROSS THE
BASIN WITH SURFACE RIDGING BUILDING IN BEHIND IT. THE RIDGE WILL
THEN SHIFT EAST ALLOWING THE NEXT FRONTAL SYSTEM TO MOVE INTO
THE NW GULF BY EARLY TUESDAY.

THE CARIBBEAN SEA...
FAIR CONDITIONS AND TRADEWIND FLOW OF 15-20 KT SPREAD ACROSS THE
MAJORITY OF THE CARIBBEAN DUE TO DRY AIR ALOFT AROUND A BROAD
UPPER LEVEL RIDGE COVERING THE BASIN. ONLY A FEW SCATTERED
SHOWERS/POSSIBLE THUNDERSTORMS ARE IN THE FAR SW GULF ACROSS
COSTA RICA AND PANAMA ASSOCIATED WITH THE MONSOON TROUGH
EXTENDING ALONG 10N. LITTLE CHANGE IS EXPECTED OVER THE NEXT 24
HOURS. A COLD FRONT CURRENTLY IN THE GULF OF MEXICO IS EXPECTED
TO REACH THE FAR NW CARIBBEAN EARLY SUNDAY.

THE ATLANTIC OCEAN...
BROAD UPPER LEVEL RIDGING COVERS THE SW NORTH ATLC SUPPORTING A
WEAK SURFACE RIDGE AROUND A 1021 MB HIGH NEAR 29N65W. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE MOVING ACROSS NORTHERN
FLORIDA OVER ATLC WATERS NORTH OF 28N WEST OF 74W ASSOCIATED
WITH A COLD FRONT IN THE GULF OF MEXICO. AN UPPER LEVEL TROUGH
OVER THE NW ATLC CONTINUES TO SUPPORT A WEAK COLD FRONT THAT
ENTERS THE DISCUSSION AREA NEAR 32N55W AND CONTINUES TO 26N65W.
POSSIBLE ISOLATED SHOWERS ARE ALONG THE AXIS. A WEAK 1021 MB
SURFACE HIGH IS ALSO TO THE EAST OF THE COLD FRONT NEAR 29N52W
HELPING PROVIDE FAIR CONDITIONS ACROSS MUCH OF THE CENTRAL ATLC.
FARTHER EAST...A NEARLY CUT-OFF UPPER LEVEL LOW NEAR 25N38W
SUPPORTS A 1016 MB SURFACE LOW NEAR 23N43W WITH AN ASSOCIATED
SURFACE TROUGH EXTENDING THROUGH THE CENTER ALONG 30N40W 20N43W.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE MAINLY EAST OF THE
TROUGH AXIS FROM 22N-26N BETWEEN 37W-40W. THE REMAINDER OF THE
EASTERN ATLC IS DOMINATED BY SURFACE RIDGING AROUND A 1030 MB
HIGH CENTERED OVER NW AFRICA. ALOFT...AN UPPER LEVEL RIDGE
COVERS THE AREA ALONG 22W.

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

$$
WALTON




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