[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 101036
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST FRI 10 DEC 2004

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1115 UTC.

...ITCZ...

AXIS OF ITCZ IS CENTERED ALONG 7N12W 5N20W 7N40W 8N60W .
SCATTERED MODERATE CONVECTION BETWEEN 7N-9N FROM 10W-33W. WIDELY
SCATTERED MODERATE CONVECTION FROM 7N-12N BETWEEN 42W-53W.

...DISCUSSION...

GULF OF MEXICO...
SHORTWAVE TROUGH CONTINUES TO PUSH THROUGH THE CENTRAL UNITED
STATES AND REMAINS THE BIGGEST WEATHER MAKER ACROSS THE AREA.
GOOD UPPER LEVEL DYNAMICS/LIFT AND AMPLE LOW LEVEL MOISTURE
ASSOCIATED WITH THIS SYSTEM IS PRODUCING SCATTERED SHOWERS AND
THUNDERSTORMS OVER THE SE UNITED STATES. A LINE OF
SHOWERS/THUNDERSTORMS EXTENDS SW INTO THE GULF OF MEXICO FROM
THE WESTERN FLORIDA PANHANDLE TO THE CENTRAL GULF NEAR 29N86W.
THIS LINE IS ALONG A SURFACE TROUGH AHEAD OF A COLD FRONT. THE
FRONT STRETCHES FROM THE TENNESSEE VALLEY SWD OVER SE ALABAMA TO
NEAR 26N95W. THE FRONT CONTINUES TO MOVING SLOWLY TO THE EAST
... A SECOND SHORTWAVE TROUGH CONTINUES ITS MARCH SWD FROM THE
SOUTHERN PLAINS AND WILL FURTHER AMPLIFY THE PATTERN SETTING UP
A LARGE-SCALE TROUGH REGIME OVER THE E UNITED STATES DURING THE
NEXT 24-36 HOURS. THIS WILL ALLOW THE COLD FRONT TO  BEGIN TO
MOVE MUCH FASTER TOWARD THE SE LATER TODAY. THE FRONT IS
FORECAST TO REACH FROM CENTRAL FLORIDA TO THE YUCATAN PENINSULA
BY TONIGHT...THEN WILL CLEAR THE GULF OF MEXICO EARLY SAT. HIGH
PRESSURE IS EXPECTED TO BUILD IN BEHIND THE FRONT SUPPORTING
BRISK NLY FLOW AND MODERATE COLD AIR ADVECTION.

CARIBBEAN...
THE CARIBBEAN REMAINS UNDER THE INFLUENCE OF STRONG MIDDLE TO
UPPER LEVEL RIDGING AND SUBSIDENCE.  A MIDDLE TO UPPER CYCLONIC
CIRCULATION OVER THE E PACIFIC ABOUT 150 NM SW OF THE NW COAST
OF COSTA RICA IS HELPING TO PRODUCE WIDELY SCATTERED ITCZ
CONVECTION OVER PANAMA AND COSTA RICA.  OTHERWISE...DRY/STABLE
CONDITIONS PREVAIL IN THE MIDDLE TO UPPER LEVELS...ESPECIALLY E
OF 70W.  AREAS OF LOW LEVEL MOISTURE ARE PRODUCING SCATTERED
CLOUDS AND ISOLATED SHOWERS OVER THE CARIBBEAN S OF 14N BETWEEN
74W-84W. MIDDLE TO UPPER LEVEL RIDGING WILL CONTINUES TO WEAKEN
OVER THE IN ADVANCE OF THE AMPLIFYING TROUGH OVER THE E UNITED
STATES AND GULF OF MEXICO.

ATLANTIC OCEAN...
LARGE SCALE ANTICYCLONE CENTERED OVER THE SE BAHAMAS DOMINATES
THE W ATLC WITH ASSOCIATED RIDGE EXTENDING NEWD INTO THE CENTRAL
ATLC ALONG 28N50W 28N40W.  THE RIDGE IS BEING PARTIALLY ERODED
BY A WEAK SHORTWAVE TROUGH DROPPING SWD ALONG 32N48W TO 29N54W.
THE RIDGE IS KEEPING THE W ATLC UNDER DRY/TRANQUIL CONDITIONS.

OVER THE CENTRAL ATLC...LOW PRESSURE NEAR 21N49W WITH A TROUGH
EXTENDS SW FROM THE CIRCULATION TO 12N53W...JUST SE OF THE
WINDWARD ISLANDS. MODERATE/STRONG SUBSIDENCE/DRY AIR IS LOCATED
ALONG AND WEST OF THE CYCLONIC CIRCULATION AND TROUGH. OVER THE
EASTERN ATLC A LARGE MID/UPPER LEVEL ANTICYCLONIC CIRCULATION IS
CENTERED NEAR 7N23W. BROAD ANTICYCLONIC FLOW COVERS THE EASTERN
ATLC S OF 23N E OF THE UPPER LOW. THIS PATTERN IS PRODUCING
DIFFLUENT MIDDLE TO UPPER LEVEL FLOW TO THE EAST OF THE UPPER
LOW AND SUPPORTING WIDESPREAD CLOUDINESS AND SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS FROM THE ITCZ NWD TO 22N BETWEEN
THE CAPE VERDE ISLANDS AND 48W.  THE STRONGEST AND MOST NUMEROUS
SHOWER/THUNDERSTORM ACTIVITY IS LOCATED FROM 6N-22N BETWEEN
23W-47W.  THIS AREA SHOULD REMAIN UNSETTLED OVER THE NEXT DAY OR
SO AS THE UPPER LOW REMAINS NEARLY STATIONARY. OVER THE FAR NE
PORTION OF THE AREA...A FAST-MOVING SHORTWAVE TROUGH IS MOVING
SE TOWARDS THE AZORES AND THE COAST OF AFRICA.

$$
JP/HC





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