[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 051137
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 9N13W 7N20W 4N30W 1N43W. SCATTERED
MODERATE CONVECTION IS FROM 3N-5N BETWEEN 28W-32W.

...DISCUSSION...

GULF OF MEXICO...
A DISSIPATING STATIONARY FRONT IS DRAPED OVER THE SE GULF FROM
NAPLES...FLORIDA TO THE NORTHEASTERN YUCATAN PENINSULA. MOISTURE
OVERRUNNING THIS BOUNDARY HAS BROUGHT WIDESPREAD SHOWERS OVER
FLORIDA AND THE EASTERN GULF THE PAST 24 HOURS. THIS FRONT HAS LOST
MUCH OF ITS PUNCH AND 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 NORTHERLY FLOW NORTH OF
THIS BOUNDARY AND A 1011 MB LOW PRES SYSTEM LIES ON THE FRONT NEAR
27N86W. A STATIONARY FRONT EXTENDS NE OF THE LOW TO JACKSONVILLE...
FLORIDA WHILE A COLD FRONT LIES SW OF THE LOW TO THE EASTERN BAY OF
CAMPECHE. THE DEEP LAYER TROUGH IS EXPECTED TO PICK UP SPEED
OVERNIGHT...SENDING ITS ASSOCIATED COLD FRONT EASTWARD...OVERTAKING
THE WEAK STATIONARY FRONT OVER THE SE GULF OF MEXICO LATER THIS
MORNING AND ALLOWING HIGH PRES TO CHARGE EASTWARD BEHIND THE COLD
FRONT OVER THE WEEKEND. THE GALE IN THE GULF IS FORECAST TO END THIS
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 SHOWS 20 TO 25 KT EASTERLY TRADEWINDS 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 31N75W TO
29N78W AND CROSSING THE FLORIDA COAST NEAR JUPITER INLET. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS CAN BE FOUND N OF THE FRONT OVER
MUCH OF FLORIDA AS WELL AS WITHIN 300 NM E OF THE FRONT N OF 27N. 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 INTO
THE CENTRAL ATLC N OF 20N. AN UPPER LOW IN THE S/CENTRAL ATLC
CURRENTLY NEAR 18N46W 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
20N44W TO 11N49W WITH SCATTERED SHOWERS FOUND WITHIN 150 NM E OF THE
TROUGH FROM 15N TO 20N. 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. A SECOND SURFACE TROUGH CAN BE FOUND FROM 29N42W TO 19N52W.
THIS TROUGH IS THE REMNANTS OF A WEAK NORTHERN STREAM FRONT THAT
STALLED HERE YESTERDAY. THE 0026 AND 0206 UTC ASCAT PASSES SHOW 20
TO 25 KT NE WINDS BETWEEN THIS TROUGH AND THE SURFACE RIDGE AXIS TO
ITS W. THIS TROUGH WILL DISSIPATE THE THE RIDGE SHIFTS E OVER THE
NEXT TWO DAYS.

$$
SCHAUER


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