[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 141801
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED DEC 14 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 4N10W 5N28W 8N45W 7N57W. SCATTERED
MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE WITHIN
90 NM ON EITHER SIDE OF THE AXIS. THE STRONGEST AND MOST
PERSISTENT SHOWERS ARE FROM 45W TO 53W. STRONG WSW FLOW IS
SHEARING THE THUNDERSTORMS TO THE NE ACROSS MUCH OF THE AXIS
BUT ESPECIALLY FROM 16W TO 32W.

...DISCUSSION...

THE GULF OF MEXICO...
A MID-LEVEL ANTICYCLONE IS CENTERED OVER THE YUCATAN PENINSULA
NEAR 19N88W.  THIS UPPER HIGH IS CAUSING DRY AIR AND FAIR
WEATHER TO DOMINATE THE SOUTHERN GULF. MOSTLY FAIR WEATHER AND
CONTINUED DRY CONDITIONS ARE EXPECTED HERE OVER THE NEXT DAY OR
TWO. SCATTERED MODERATE TO STRONG SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED FROM THE UPPER TEXAS COAST LEADING INTO SOUTHWESTERN
LOUISIANA. THIS PRECIPITATION...IN THE RETURN SURFACE WIND FLOW
FIELD...IS OCCURRING IN ADVANCE OF A COLD FRONT WHICH NOW RUNS
FROM NORTH TEXAS TOWARD THE FAR WEST TEXAS. BROKEN TO OVERCAST
MULTILAYERED CLOUDS AND POSSIBLE PRECIPITATION ARE FOUND NORTH
OF 24N. SOME OF THE DYNAMICAL MODELS FORECAST THE FRONT TO
WEAKENING AS IT PROGRESSES TO THE SOUTHEAST. THE SHORT TERM
FORECAST IS FOR SCATTERED SHOWERS AND ISOLATED STRONG
THUNDERSTORMS ALONG THE U.S. GULF COAST AHEAD AND ALONG THE
FRONT DURING THE NEXT 24 HOURS.

THE CARIBBEAN SEA...
THE UPPER RIDGE OVER THE YUCATAN PENINSULA IS ALSO ENHANCING DRY
AIR IN THE CARIBBEAN SEA.  THERE ARE ONLY AREAS OF HIGH CLOUDS
SOUTH OF THE CUBA, HISPANIOLA AND PUERTO RICO. ISOLATED TO WIDELY
SCATTERED SHOWERS...IN WARM TOP CLOUDS...ARE BLOWING OFF THE
WATER TOWARD THE COAST OF CENTRAL AMERICA FROM PANAMA TO
NICARAGUA. THE SUBTROPICAL JET STREAM IS PUSHING HIGH CLOUDS
THROUGH THE AREA IN THE UPPER LEVELS WEST TO SOUTHWESTERLY FLOW.
FAIR CONDITIONS ARE EXPECTED OVER THE NEXT COUPLE OF DAYS, WITH
THE BEST CHANCE OF SHOWERS IN THE SW CARIBBEAN SEA. BROAD SURFACE
LOW PRESSURE IS FORECAST TO REMAIN THE SOUTHWESTERN CORNER OF
THE AREA. ANY AMOUNT OF PRECIPITATION ALSO MAY BE ENHANCED BY
THE ITCZ.

THE REMAINDER OF THE ATLANTIC OCEAN...
A DEEP LAYER TROUGH HAS MOVED INTO THE CENTRAL ATLANTIC. THE
CYCLONIC FLOW AROUND THIS TROUGH COVERS THE AREA NORTH OF 20N
BETWEEN 50W AND 63W. WIDELY SCATTERED TO SCATTERED MODERATE
SHOWERS AND ISOLATED STRONG THUNDERSTORMS ARE WITHIN 120 NM ON
EITHER SIDE OF 32N52W 27N55W 23N59W. THIS TROUGH IS LIFTING OUT
OF THE SUB-TROPICAL AREAS AS IT MOVES TO THE NE AND TAKING MOST
OF ITS MOISTURE WITH IT. WEST OF THE TROUGH, COLD AIR AND
WIDESPREAD TYPICAL STRATOCUMULUS CLOUDS HAVE SPREAD ACROSS THE
WESTERN ATLANTIC TO THE WEST OF THIS TROUGH. IN THE EASTERN
ATLANTIC THERE IS A STRONG 1046 MB SURFACE HIGH NEAR 50N20W.
THIS HIGH PRESSURE SYSTEM IS CAUSING FAIR WEATHER ACROSS MOST
OF THE EASTERN ATLANTIC. FAIR WEATHER IS FOUND PRACTICALLY
EVERYWHERE EXCEPT FOR THE CLOUDS AND PRECIPITATION WITH THE
CENTRAL ATLANTIC TROUGH. NO BIG CHANGES ARE EXPECTED OVER THE
NEXT 24 HOURS.

$$
JC/MT

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