[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 050603
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SAT DEC 05 2009

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0345 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 6N10W 5N20W 3N30W 1N45W. SCATTERED
MODERATE CONVECTION IS FROM 5N-8N BETWEEN 30W-35W.

...DISCUSSION...

GULF OF MEXICO...
A STATIONARY FRONT IS DRAPED OVER THE SE GULF FROM NAPLES...FLORIDA
TO THE NORTHERN YUCATAN PENINSULA WITH A 1010 MB LOW PRES SYSTEM
ALONG THE BOUNDARY NEAR 25N83W. MOISTURE OVERRUNNING THIS BOUNDARY
HAS BROUGHT WIDESPREAD SHOWERS OVER FLORIDA AND THE EASTERN GULF
TODAY. THIS FRONT HAS LOST MUCH OF ITS PUNCH OVER THE LAST 24
HOURS...BUT IT IS ABOUT TO BE REINVIGORATED BY A DEEP LAYER TROUGH
CURRENTLY MAKING ITS THROUGH THE CENTRAL GULF. AT THE SURFACE...THIS
DEEP LAYER TROUGH IS ASSOCIATED WITH A SECONDARY SURGE OF COLD...DRY
AIR WITH DEW POINTS IN THE 40S NW OF THE COLD FRONT. GALE FORCE
WINDS CAN BE FOUND IN THE NORTHEASTERLY FLOW NORTH OF THIS BOUNDARY
AND A 1011 MB LOW PRES SYSTEM LIES ON THE FRONT NEAR 27N90W. THE
DEEP LAYER TROUGH IS EXPECTED TO PICK UP SPEED OVERNIGHT...SENDING
ITS ASSOCIATED COLD FRONT TO OVERTAKE THE WEAK STATIONARY FRONT OVER
THE SE GULF OF MEXICO SAT AND ALLOW HIGH PRES TO CHARGE EASTWARD
BEHIND THE COLD FRONT OVER THE WEEKEND. GALES IN THE GULF ARE
FORECAST TO END SAT AFTERNOON.

CARIBBEAN SEA...
THE CARIBBEAN CONTINUES TO BE MARKED BY STRONG SUBSIDENCE AND
LIMITED MOISTURE...BRINGING TRANQUIL WEATHER TO MUCH OF THE AREA.
SCATTERED SHOWERS ARE PRIMARILY LIMITED TO E OF 70W AT THIS TIME.
THE 0204 UTC ASCAT PASS SHOWS 20 TO 25 KT EASTERLY TRADE WINDS OVER
MUCH OF THE CENTRAL CARIBBEAN WITH WINDS PICKING UP TO 30 KT NEAR
THE CLIMATOLOGICAL LOW PRES OVER NORTHERN COLOMBIA. THESE TRADE
WINDS ARE EXPECTED TO WEAKEN TO 20 KT THROUGH SUN AS THE 1025 MB
HIGH PRES SYSTEM CURRENTLY NEAR 32N52W WITH A RIDGE EXTENDING SW TO
COZUMEL...MEXICO IS FORCED EASTWARD BY THE AFOREMENTIONED DEEP
LAYER TROUGH SWEEPING THROUGH THE GULF OF MEXICO. THIS WILL REDUCE
THE PRES GRADIENT AND WINDS OVER THE CENTRAL AND EASTERN CARIBBEAN.
THE COLD FRONT ASSOCIATED WITH THIS DEEP LAYER TROUGH SHOULD REACH
THE YUCATAN CHANNEL THIS AFTERNOON...BRINGING A CHANCE OF SHOWERS
AND THUNDERSTORMS TO THE NW CARIBBEAN ALONG WITH 20 KT N WINDS N OF
THE FRONT. THE FRONT IS EXPECTED TO STALL OVER THE NW CARIBBEAN AND
DISSIPATE SUN.

ATLANTIC OCEAN...
A WEAK STATIONARY FRONT EXTENDS INTO THE W ATLC NEAR 31N74W TO
29N78W AND CROSSING THE FLORIDA COAST NEAR POMPANO BEACH BEFORE
EXTENDING INTO THE GULF OF MEXICO. SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS CAN BE FOUND N OF THE FRONT OVER MUCH OF FLORIDA AS
WELL AS OVER THE NORTHERN BAHAMAS AND ELSEWHERE WITHIN 60 NM SE OF
THE FRONT. AS MENTIONED IN THE GULF OF MEXICO SECTION...THIS WEAK
FRONTAL BOUNDARY WILL BE OVERTAKEN BY THE DEEP LAYER TROUGH
CURRENTLY OVER THE CENTRAL GULF...WITH THE ASSOCIATED SURFACE COLD
FRONT MOVING THROUGH FLORIDA BY SUNSET TODAY AND CARRYING THE FRONT
EASTWARD THROUGH THE NORTHERN PORTION OF THE FORECAST AREA WHILE THE
SOUTHERN PORTION STALLS NEAR THE STRAITS OF FLORIDA SUN. THIS
ADVANCING COLD FRONT WILL SHIFT THE SURFACE RIDGE CURRENTLY
EXTENDING FROM A 1025 MB HIGH PRES SYSTEM NEAR 32N52W SW TO NEAR
COZUMEL...MEXICO EASTWARD THROUGH INTO THE CENTRAL ATLC N OF 20N. AN
UPPER LOW IN THE S/CENTRAL ATLC CURRENTLY NEAR 19N45W IS EXPECTED TO
BE ABSORBED BY AN AMPLIFYING...POSITIVELY TILTED UPPER TROUGH AS THE
DEEP LAYERED RIDGE TO ITS WEST IS FORCED EASTWARD. THIS LOW HAS AN
ASSOCIATED SURFACE TROUGH FROM 23N43W TO 15N47W WITH SCATTERED
MODERATE CONVECTION FOUND WITHIN 210 NM E OF THE TROUGH FROM 16N TO
20N. THE 0026 AND 0206 UTC ASCAT PASSES SHOW 20 TO 25 KT WINDS
BETWEEN THIS TROUGH AND THE SURFACE RIDGE AXIS TO ITS W. A 100 KT
WEST-SOUTHWESTERLY UPPER JET LIES SE OF THE UPPER LOW AND IS
TRANSPORTING TROPICAL MOISTURE NORTHEASTWARD TOWARD WEST
AFRICA...WITH MAINLY CLOUDY SKIES FOUND ALONG THE ROUTE FROM THE
FRENCH GUIANA TO CAPE VERDE ISLANDS AS A RESULT.

$$
SCHAUER


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