[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 261745
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST FRI DEC 26 2008

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.

...THE ITCZ...
THE ITCZ IS ANALYZED ALONG 8N12W 4N30W 0N48W. ISOLATED MODERATE
CONVECTION IS WITHIN 60 NM OF THE ITCZ FROM 13W-23W.  SCATTERED
MODERATE CONVECTION IS WITHIN 120 NM OF THE ITCZ FROM 28W-38W.

...DISCUSSION...

GULF OF MEXICO...
THE GULF IS RELATIVELY TRANQUIL WITH NO GALES AND NO AREAS OF
DEEP CONVECTION.  A SURFACE HIGH TO THE NORTHEAST OF FLORIDA IS
INDUCING SURFACE WINDS OF 20 KT OR LESS FROM THE EAST TO
SOUTHEAST.  THESE WINDS SHOULD BE ENHANCED SOME DURING THE NEXT
24 HOURS IN ADVANCE OF THE NEXT COLD FRONT...WHICH SHOULD REACH
THE NORTHWESTERN GULF BY EARLY SUNDAY.  IN THE UPPER
LEVELS...SUBSIDENT RIDGING IS PRESENT WITH SOUTHWESTERLY WINDS
FROM 30-50 KT PREVAILING.

CARIBBEAN SEA...
SURFACE RIDGING ALONG 30N IN THE ATLANTIC IS HELPING TO PRODUCE
BRISK EAST TO NORTHEASTERLY TRADEWINDS THIS MORNING.  A 1040 UTC
QUIKSCAT PASS ALONG WITH SHIP REPORTS INDICATE THAT NORTH OF
COLUMBIA THE WINDS ARE UP TO GALE FORCE.  THE TRADEWINDS MAY
MODERATE SLIGHTLY OVER THE NEXT TWO DAYS AS THE BERMUDA HIGH
WEAKENS TO THE NORTH...BUT WINDS SHOULD REMAIN AT LEAST 20 KT
THROUGHOUT THE CARIBBEAN.  NO AREAS OF DEEP CONVECTION ARE
OBSERVED TODAY UNDER THE TYPICALLY SUBSIDENT FLOW FOR THIS TIME
OF YEAR.  IN THE UPPER LEVELS...RIDGING PREVAILS ALONG 75W WITH
SOUTHWESTERLY WINDS UP TO 60 KT WEST OF THE RIDGE AXIS AND
NORTHWESTERLY WINDS ABOUT THE SAME MAGNITUDE EAST OF THE AXIS.

ATLANTIC OCEAN...
A COLD FRONTAL BOUNDARY IS DRAPED ACROSS 31-32N FROM THE GEORGIA
COASTLINE EASTWARD TO 70W.  SCATTERED TO NUMEROUS LOW-TOPPED
SHOWERS ARE LIKELY ASSOCIATED WITH THIS FEATURES...THOUGH NO
DEEP CONVECTION IS BEING OBSERVED.  A SECOND COLD FRONT IS
OBSERVED IN THE EASTERN ATLANTIC FROM 32N19W TO 22N27W TO 20N39W
WITH A SURFACE TROUGH EXTENDING FARTHER WESTWARD TO 20N58W.
WHILE NO DEEP CONVECTION IS SEEN TO BE ASSOCIATED WITH THESE
FEATURES...SCATTERED TO NUMEROUS SHOWERS ARE LIKELY OCCURRING
WITHIN 60 NM OF THE FRONT AND TROUGH.  A DISSIPATING 1028 MB
HIGH IS CENTERED NEAR 30N73W WITH RIDGING ALONG 30N WELL TO THE
EAST OF THE HIGH.  NO GALES ARE CURRENTLY PRESENT IN THE
REGION.  SURFACE WINDS ARE LIGHT NEAR THE SURFACE RIDGE...THOUGH
EAST TO NORTHEAST WINDS UP TO 25 KT ARE OCCURRING SOUTH OF 25N
ACROSS THE ATLANTIC.  THE COLD FRONT IN THE WESTERN ATLANTIC
SHOULD CONTINUE PROGRESSING SOUTHEASTWARD AND BRING SOME BRISK
NORTH TO NORTHEAST WINDS ALONG THE NORTHERN PORTION OF THIS
REGION DURING THE NEXT TWO DAYS.  IN THE UPPER LEVELS...THERE IS
A TROUGH EXTENDING WEST-SOUTHWESTWARD FROM A CLOSED LOW NEAR THE
AZORES TO 30N33W TO 25N41W TO 15N56W.  ON THE EQUATORWARD SIDE
OF THE UPPER TROUGH...THERE IS WIDESPREAD UPPER-LEVEL CLOUDINESS
ORIGINATING FROM THE ITCZ OUTFLOW WHICH IS ENHANCED BY RIGHT
ENTRANCE REGION OF A SOUTHWESTERLY 130 KT JET.

$$
LANDSEA


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