[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 122335
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST MON DEC 12 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 8N13W 8N34W 3N42W 3N52W.  ISOLATED
MODERATE FROM 3N-10N BETWEEN 31W-40W.  SCATTERED MODERATE CONVECTION
FROM 6N-8.5N BETWEEN 17W-31W.

...DISCUSSION...

GULF OF MEXICO...
UPPER RIDGING CONTROLS THE W GULF OF MEXICO WITH WLY WINDS ALOFT
OVER THE REST OF THE GULF FROM ANOTHER SHORTWAVE DROPPING INTO THE
SE USA.  SCATTERED TO OCCASIONALLY BROKEN HIGH CLOUDS ARE N OF 24N
IN THE REGION THICKEST IN THE W GULF.  THE FRONT HAS CLEARED THE SE
GULF OF MEXICO AND HAS DISSIPATED BEFORE MOVING INTO THE EXTREME SE
BAY OF CAMPECHE.  THERE WASN'T ENOUGH PUSH DOWN THE SIERRA MADRES TO
CLEAR OUT THE SW GULF WHICH IS PLAGUED BY MOSTLY CLOUDY SKIES AND
ISOLATED SHOWERS S OF 25N W OF 93W.  THIS MOISTURE IS EXPECTED TO
LINGER OVERNIGHT AND START MOVING NORTHWARD OVER TEXAS TOMORROW AS
HIGH PRESSURE SHIFTS INTO THE NE GULF.  THIS MOISTURE WILL HELP FUEL
A FEW TSTMS ALONG A FRONT THAT IS SCHEDULED TO ENTER THE NW GULF
LATE WED.

CARIBBEAN SEA...
ISOLATED TSTMS ARE IN THE EXTREME SW CARIBBEAN S OF 12N W OF 79W
ASSOCIATED WITH A LITTLE UPPER DIVERGENCE NEAR THE ITCZ.  ISOLATED
SHOWERS ARE BEHIND A WEAK COLD FRONT FROM CENTRAL CUBA TO NEAR
COZUMEL IN ADDITION TO SCATTERED/BROKEN LOW CLOUDS N OF 19N W OF
GRAND CAYMAN.  WEAK UPPER TROUGHING LIES IN THE NW CARIBBEAN... A
LITTLE RIDGING IN THE SW CARIBBEAN FROM NW COLOMBIA TO HONDURAS THEN
WLY WINDS ALOFT FOR THE E CARIBBEAN.  STRONG SUBSIDENCE CONTINUES IN
THE E CARIBBEAN WITH ONLY LOW-TOPPED SHOWERS NOTED.. MOST NUMEROUS
FROM MARTINIQUE WESTWARD TO WITHIN 120 NM OF 15N67W WITH A FEW
SHOWERS NEAR BARBADOS.  AGAIN NO LARGE CHANGES ARE EXPECTED WITH
MOST FRONTS HAVING ONLY A SMALL EFFECT BY THE TIME THEY REACH THE NW
CARIBBEAN.

ATLANTIC OCEAN...
FAST-MOVING SHORTWAVE EXTENDS FROM NEAR BERMUDA TO THE CENTRAL
BAHAMAS WITH ASSOCIATED FRONT ABOUT 60 NM E OF BERMUDA APPROACHING
THE SE BAHAMAS.  THE SHORTWAVE IS KICKING OFF SCATTERED MODERATE
CONVECTION WITHIN 60 NM OF THE FRONT N OF 29N WITH ISOLATED ACTIVITY
WITHIN 180 NM N OF 25N.  FARTHER E...RIDGING CONTROLS THE W-CENTRAL
ATLC FROM E OF THE LESSER ANTILLES TO 32N56W BERMUDA.  HIGH CLOUDS
FROM THE APPROACHING TROUGH ARE ROUNDING THE N SIDE OF THE RIDGE N
OF 27N BETWEEN 50W-65W OTHERWISE MODERATE/STRONG SUBSIDENCE
DOMINATES W OF 30W AND BEHIND THE SHORTWAVE.   IN THE NE ATLC... 995
MB LOW IS NEAR 35N32W WITH STORM FORCE WINDS.  THIS LOW IS
EMBEDDED IN LARGE UPPER TROUGH WITH AXIS FROM THE LOW SW TO 19N41W.
STATIONARY FRONT IS WELL E OF THE LOW AND IS DISSIPATING FROM 23N20W
TO 31N22W... STILL ASSISTING SOME TSTMS N OF 27N NEAR AND W OF THE
CANARY ISLAND UNTIL THE FRONTAL BOUNDARY.  THE LOW IS SEPARATING
FROM ITS FRONTS AND CONVECTION IS DEEPENING A LITTLE AROUND THE
CENTER... THOUGH IT REMAINS QUITE SHALLOW.  THE SATELLITE
PRESENTATION IS ALSO BECOMING MORE SUBTROPICALISH WITH TIME AS THE
SYSTEM LOSES FRONTAL CHARACTERISTICS AND SOME SHALLOW CONVECTION
FORMSNEAR THE CENTER.  HOWEVER COMPUTER MODELS ARE A LITTLE LESS
ENTHUSIASTIC ABOUT THIS LOW ACQUIRING SIGNIFICANT SUBTROPICAL/
TROPICAL CHARACTERISTICS WITH TIME THAN YESTERDAY...  BUT IT IS
WORTH WATCHING UNTIL IT MERGES WITH AN APPROACHING TROUGH IN A FEW
DAYS.  A SURFACE TROUGH EXTENDS FROM 30N27W TO 24N35W WITH THE UPPER
TROUGH FORCING AN AREA OF WIDELY SCATTERED WEAK CONVECTION FROM
23.5N-27N BETWEEN 30W-35W.  DRY AIR ALOFT DOMINATES THE TROPICAL
ATLC EXCEPT SE OF A LINE FROM 17N16W TO 6N41W WHERE ITCZ CONVECTION
HAS FLARED UP DUE TO THE UPPER TROUGH DEEPENING IN THE E ATLC.
OBVIOUSLY TRADES ARE CONSIDERABLY WEAKER THAN AVERAGE S OF THE LARGE
LOW AND REMAIN CLOSE TO AVERAGE OR A LITTLE ABOVE W OF 50W INTO THE
CARIBBEAN.

$$
BLAKE


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