[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 100019
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST SAT DEC 09 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...
CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...
NORTHEASTERN SECTIONS OF SOUTH AMERICA...AND THE 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2345 UTC.

...THE ITCZ...
5N9W 3N20W 5N35W TO 3N53W IN EXTREME NORTHEASTERN BRAZIL
AND SOUTHERN FRENCH GUIANA. ISOLATED MODERATE SHOWERS IN
INDIVIDUAL CLUSTERS ARE SOUTH OF 5N BETWEEN THE PRIME
MERIDIAN AND 50W...AND FROM 5N TO 10N BETWEEN 30W AND 60W.

...DISCUSSION...
THE GULF OF MEXICO...
A SLOWLY LIFTING MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH
RUNS FROM EASTERN TEXAS/LOUISIANA TO THE BAY OF CAMPECHE.
A SUBTROPICAL JET IS AT THE BASE OF THIS TROUGH AND EXTENDS
ACROSS THE SOUTHERN GULF AND THE STRAITS OF FLORIDA. CORE
WINDS ARE NEAR 100 KT IN THE SOUTHEASTERN CORNER OF THE AREA
AND THROUGH THE STRAITS OF FLORIDA BASED ON THE 09/2100 UTC
CIMSS DERIVED UPPER LEVEL WINDS. WIDESPREAD CLOUDINESS COVERS
THE AREA IN UPPER LEVEL DIFFLUENT FLOW. STRONG SURFACE HIGH
PRESSURE GOES FROM THE SOUTHEASTERN U.S.A. ACROSS THE ENTIRE
GULF OF MEXICO. ONE SURFACE TROUGH IS IN THE SOUTHEASTERN GULF
AND A SECOND TROUGH IS IN THE SOUTHWESTERN CORNER. SURFACE
NORTHEASTERLY WINDS COVER THE AREA. THE WIND SPEEDS ARE THE
FASTEST IN THE EASTERN GULF WITH BUOYS REPORTING SPEEDS FROM
20 TO 30 KT. EACH SURFACE TROUGH IS PRODUCING A LOW-LEVEL
CONFLUENT LINE OF CLOUDS AND A KINK IN THE ISOBARIC PATTERN.
SHOWERS ARE POSSIBLE NEAR THESE TROUGHS. THE STRONG HIGH
PRESSURE SYSTEM WILL SLIDE EASTWARD SLOWLY ALLOWING WINDS
TO SLACKEN A LITTLE. THE WIND SPEEDS WILL REMAIN QUIET BREEZY
TO WINDY IN THE EASTERN GULF DURING THE NEXT FEW DAYS AS THE
PRESSURE GRADIENT REMAINS FAIRLY TIGHT. A COLD FRONT MAY ENTER
THE NORTHWESTERN GULF LATE TUESDAY. THE GFS MODEL SHOWS A FAIR
AMOUNT OF MOISTURE LINGERING AND INCREASING AHEAD OF THE FRONT.

THE CARIBBEAN SEA...
A DISSIPATING STATIONARY FRONT PASSES THROUGH THE WINDWARD
PASSAGE NEAR 20N74W TO JUST OFF NORTHWESTERN JAMAICA...TO
NORTHEASTERN NICARAGUA. WEAKENING BUT LINGERING SHOWERS AND
THUNDERSTORMS FROM 16N TO 19N BETWEEN 80W AND 86W. ISOLATED
MODERATE SHOWERS FROM JAMAICA INTO THE WINDWARD PASSAGE.
UPPER LEVEL SOUTHWESTERLY WINDS ARE ON TOP OF THE DISSIPATING
STATIONARY FRONT...ON THE WESTERN PERIPHERY OF AN UPPER LEVEL
RIDGE ALONG 76W. NORTHEASTERLY WINDS IN THE 20 TO 25 KT RANGE
HAVE BEEN COMMON BEHIND THE FRONT THROUGHOUT THE AFTERNOON.
CONDITIONS ARE PRETTY QUIET IN THE CENTRAL AND EASTERN CARIBBEAN
AS DRY AIR...ASSOCIATED WITH NORTHERLY WIND FLOW ON THE EASTERN
SIDE OF THE UPPER RIDGE...COVERS THE AREA. THERE ARE TYPICAL LOW
LEVEL PATCHES OF MOISTURE DRIVEN BY RATHER STRONG EASTERLY TRADE
WINDS UNDERNEATH THE SUBSIDENCE INVERSION. STRONG NORTHEASTERLY
TO EASTERLY WINDS WILL CONTINUE ACROSS THE AREA THROUGH TUESDAY
AS STRONG HIGH PRESSURE REMAINS NORTH OF THE REGION. THE FRONT
OR MORE LIKELY REMNANT TROUGH WILL WEAKEN SLOWLY DURING THE NEXT
FEW DAYS.

THE ATLANTIC OCEAN...
A CENTRAL ATLANTIC OCEAN COLD FRONT PASSES THROUGH 32N54W TO
27N60W AND 23N66W. A STATIONARY FRONT CONTINUES FROM 23N66W TO
THE WINDWARD PASSAGE NEAR 20N74W. BROKEN TO OVERCAST MULTILAYERED
CLOUDS AND POSSIBLE SHOWERS ARE WITHIN 120 TO 180 NM ON EITHER
SIDE OF THE LINE THROUGH 32N52W 27N58W 23N64W 21N76W. A MIDDLE
TO UPPER LEVEL SHORTWAVE TROUGH PASSES THROUGH 32N74W TO 29N79.
UPPER LEVEL SOUTHWESTERLY WINDS BLOW FROM CUBA ACROSS THE
BAHAMAS NORTHEASTWARD BEYOND BERMUDA. A MIDDLE TO UPPER LEVEL
TROUGH EXTENDS FROM A CYCLONIC CIRCULATION CENTER NEAR 22N36W
TO 17N52W TO 15N60W TO 14N68W IN THE EAST CENTRAL CARIBBEAN SEA.
MIDDLE TO UPPER LEVEL FLOW IS WITHIN 300 TO 400 NM ON EITHER
SIDE OF THE AXIS BETWEEN 40W AND 60W. SCATTERED MODERATE SHOWERS
TO ISOLATED STRONG THUNDERSTORMS ARE FROM 24N TO 26N BETWEEN 31W
AND 34W. ISOLATED MODERATE SHOWERS ARE ELSEWHERE FROM 20N TO
27N BETWEEN 30W AND 38W.

$$
MT



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