[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 021748
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST TUE DEC 02 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 1715 UTC.

...THE ITCZ...
THE ITCZ AXIS IS ANALYZED ALONG 8N12W 7N19W 8N38W 5N54W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 3N-9N
BETWEEN 12W-19W. SCATTERED MODERATE CONVECTION IS FROM 4N-10N
BETWEEN 29W-39W AND FROM 5N-10N BETWEEN 43W-50W.

...DISCUSSION...

GULF OF MEXICO...
A DEEP LAYERED TROUGH IS ACROSS THE SE CONUS AND THE FLORIDA
PANHANDLE TOWARD THE SW GULF OF MEXICO AND IS SUPPORTING A COLD
FRONT THAT PASSES THROUGH A FORT PIERCE TO NAPLES FLORIDA LINE
AND SW TO NEAR 24N85W TO 23N90W. MIDDLE TO UPPER LEVEL DRY AIR
AND STRONG SUBSIDENCE IS OVER THE ENTIRE GULF REGION. BROKEN TO
OVERCAST MIDDLE AND HIGH CLOUDS ARE OBSERVED IN THE SE GULF AND
STRAITS OF FLORIDA WITH POSSIBLE ISOLATED SHOWERS WITHIN 90 NM
OF THE FRONTAL BOUNDARY. BEHIND THE FRONT SCATTERED COLD AIR
STRATOCUMULUS CLOUDS ARE EVIDENT ON SATELLITE IMAGERY N OF 24N
AND E OF 89W. NEXT COLD FRONTAL BOUNDARY IS FORECAST TO ENTER
THE NW GULF ON THURSDAY MORNING.

CARIBBEAN SEA...
A COLD FRONT ENTERS THE WRN CARIBBEAN FROM ACROSS ERN CUBA TO
NEAR 18N80W AND INTO A 1015 MB SURFACE LOW PRESSURE NEAR 15N83W.
SCATTERED SHOWERS AND TSTMS ARE WITHIN 150 NM ON EITHER SIDE OF
THE FRONT WITH SCATTERED MODERATE CONVECTION ACROSS THE SW
CARIBBEAN S OF 15N AND W OF 76W. THIS FRONT IS BEGINNING TO
STALL AND IS FORECAST TO TURN STATIONARY OVER THE NEXT 12-24
HOURS ACROSS THE WRN CARIBBEAN. A SURFACE TROUGH IS LOCATED IN
THE ERN CARIBBEAN ALONG 68W SOUTH OF 16N. SCATTERED SHOWERS ARE
FROM 12N-17N BETWEEN 65W-71W. BROKEN LOW TO MIDDLE LEVEL CLOUDS
ARE ACROSS THE LEEWARD ISLANDS AND PUERTO RICO USHERED IN ON
E-NE 15-20 KT TRADES. IN THE UPPER LEVELS...A SHARP AMPLIFIED
RIDGE IS LOCATED IN THE W ATLC AND EXTENDS A RIDGE AXIS INTO THE
CENTRAL CARIBBEAN THROUGH THE MONA PASSAGE TO NEAR 12N76W.

ATLANTIC OCEAN...
A COLD FRONT IS SUPPORTED BY THE AFOREMENTIONED UPPER LEVEL
TROUGHING ACROSS THE ERN GULF OF MEXICO AND EXTENDS SW FROM A
1017 MB LOW THAT IS CENTERED IN THE W ATLC NEAR 32N76W TO NEAR
FORT PIERCE FLORIDA. SCATTERED SHOWERS ARE WITHIN 60 NM OF THE
FRONT N OF 26N. ANOTHER COLD FRONT ENTERS THE W ATLC NEAR 32N69W
AND EXTENDS SW OVER CAT ISLAND AND THE EXUMA CAYS IN THE BAHAMAS
TO OVER ERN CUBA AND INTO THE WRN CARIBBEAN. UPPER LEVEL SWLY
WIND FLOW FROM A LARGE-SCALE RIDGE CENTERED NEAR 26N62W IS
CREATING A LARGE AREA OF UPPER DIFFLUENCE INDUCING SCATTERED
SHOWERS AND ISOLATED TSTMS FROM 20N TO BEYOND 32N BETWEEN
69W-80W ACROSS MUCH OF THE BAHAMAS AND ERN CUBA. THE UPPER LEVEL
RIDGE AXIS LIES ALONG A LINE FROM THE MONA PASSAGE TO BEYOND
32N59W. A SURFACE RIDGE IS ALONG A LINE FROM 23N68W TO BEYOND
32N56W. A LARGE-SCALE DEEP LAYER TROUGH COVERS THE CENTRAL ATLC
WITH AN UPPER LOW CENTERED NEAR 29N38W. BROAD CYCLONIC SURFACE
FLOW IS OBSERVED BETWEEN 25W-47W WITH ONE 1013 MB SURFACE LOW
NEAR 29N40W AND ANOTHER 1012 MB SURFACE LOW N OF THE AREA NEAR
34N33W. A SURFACE TROUGH CURVES FROM THIS LOW TO 32N31W TO
27N30W AND SW TO NEAR 11N47W. SCATTERED SHOWERS AND POSSIBLE
ISOLATED TSTMS ARE WITHIN 250 NM ON EITHER SIDE OF THE
TROUGH...UNDER AN UPPER LEVEL SOUTHWESTERLY WIND FLOW REGIME
LOCATED ON THE ERN SIDE OF A TROUGH AND ON THE WRN SIDE OF A
RIDGE. THIS RIDGE IS CENTERED OVER SIERRA LEONE AND IS PROVIDING
AN UPPER LEVEL DIFFLUENT PATTERN SUPPORTING THE CONVECTION ALONG
THE ITCZ AXIS.

$$
HUFFMAN




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