[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 162349
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST THU 16 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...

ITCZ IS CENTERED ALONG 7N1W 7N15W 5N25W 8N35W 7N45W 8N60W 5N80W.
ISOLATED MODERATE CONVECTION IS FROM 3N-11N BETWEEN 12W-26W.
SCATTERED MODERATE CONVECTION IS FROM 8N-13N BETWEEN 41W-47W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD POSITIVELY TILTED UPPER LEVEL TROF EXTENDING FROM THE
WESTERN GREAT LAKES TO THE DESERT SOUTHWEST IS INCREASING MOIST
SWLY FLOW OVER THE GULF OF MEXICO AS IT SAGS STEADILY TO THE S.
WIDESPREAD MID/UPPER LEVEL CLOUDINESS IS MOVING FROM SW TO NE
FROM THE ACAPULCO/MEXICO CITY AREA INTO THE W GULF. A STATIONARY
FRONT HAS FORMED BENEATH THIS FLOW FROM SW LOUISIANA NEAR 30N94W
TO SE OF BROWNSVILLE TEXAS TO NEAR 24N97W WITH BROAD ISENTROPIC
LIFT FROM THE SE PRODUCING LOW-LEVEL CLOUDINESS AND LIGHT
SHOWERS OVER SE TEXAS. DOPPLER RADAR AND LIGHTNING DETECTION
ALSO INDICATE A FEW SHOWERS AND TSTMS OVER THE COASTAL WATERS N
OF 24N BETWEEN 93W-97W. THERE IS AN APPRECIABLE AIR-SEA
TEMPERATURE DIFFERENCE ACROSS THE TROUGH... FROM ABOUT LOWER 70S
F OVER THE GULF WATERS TO THE 40S AND 50S F OVER SE TEXAS. THE
FRONT IS EXPECTED TO SAG SWD OVER THE GULF WATERS FRI AND SAT
BEFORE A STRONGER SURGE OF COLD AIR MOVES IN ON SUN.
ELSEWHERE...STRONG HIGH PRES OVER THE SE U.S. IS FUNNELING AN
ALMOST SOLID LAYER OF STRATOCUMULUS FROM THE W ATLC WATERS TO
THE FLORIDA EAST COAST...PRODUCING A FEW ISOLATED SHOWERS AND
DRIZZLE ESPECIALLY FROM WEST PALM BEACH TO JACKSONVILLE.

CARIBBEAN...
A DIFFUSE COLD FRONT CONTINUES TO PUSH SWD OVER THE W CARIBBEAN
AND NOW EXTENDS FROM THE E COAST OF DOMINICAN REPUBLIC SW
TO THE COAST OF NICARAGUA WHERE IT HANGS UP ALONG THE CNTRL
AMERICAN MOUNTAINS. PATCHY LOW/MID LEVEL CLOUDS ARE LOCATED
BEHIND THE FRONT BUT THE COVERAGE AND THICKNESS IS NOT AS GREAT
AS YESTERDAY AS THE AIR MASS MODIFIES OVER THE TROPICAL WATERS.
A SFC TROUGH AHEAD OF THE FRONT EXTENDS FROM PUERTO RICO SW TO
NEAR THE PANAMA CANAL AND IS INCREASING LOW-LEVEL CONVERGENCE
OVER PUERTO RICO.  THE UPPER LEVEL FLOW IS PREDOMINANTLY
WESTERLY WITH LITTLE MOISTURE STREAMING IN FROM THE PACIFIC.

WEST ATLANTIC...
A FLATTENING UPPER LEVEL TROUGH IS LIFTING TO THE NE NEAR 60W
WITH BROAD WESTERLY FLOW REPLACING IT FROM THE U.S. EAST COAST.
A COLD FRONT IS AHEAD OF THIS TROUGH FROM 32N55W TO 26N60W TO
THE E COAST OF DOMINICAN REPUBLIC WITH A LARGE AREA OF
STRATOCUMULUS CLOUDS BEHIND THE FRONT ORIGINATING FROM OFF THE
U.S. COAST. A 250 NM THICK BAND OF LOW/MID CLOUDS IS LOCATED
ALONG THE FRONT WITH ISOLATED SHOWERS/TSTMS FORMING NEAR THE
ACTUAL BOUNDARY.

REMAINDER OF ATLANTIC...
RIDGE AXIS EXTENDS NE OF THE NORTHERN LEEWARD ISLANDS NEAR
20N60W TO BEYOND 32N43W.  FURTHER EAST A TROUGH AXIS EXTENDS
FROM MOROCCO NEAR 30N10W TO 10N50W.  A DIFFLUENT REGION IS EAST
OF THE TROUGH AXIS FROM THE EQUATOR TO 20N BETWEEN 25W AND THE
PRIME MERIDIAN.  ELSEWHERE...A SMALL SURFACE TROUGH IS LOCATED
JUST OFFSHORE THE WESTERN SAHARA/MAURITANIA COAST FROM 24N21W TO
18N20W MOVING QUICKLY SW WITHIN STRONG NELY SFC LOW.  NO
SIGNIFICANT CONVECTION IS NOTED.

$$
FORMOSA




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