[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 181749
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST FRI DEC 18 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 8N12W 5N20W 6N30W 5N40W 2N52W.
WIDELY SCATTERED MODERATE CONVECTION IS FROM 3N-6N BETWEEN
14W-23W.

...DISCUSSION...

GULF OF MEXICO...
AS OF 1500 UTC...A 1022 MB HIGH IS CENTERED OVER N MEXICO NEAR
26N103W. A 1001 MB LOW IS OVER THE FLORIDA PANHANDLE NEAR
30N86W. A TIGHT SURFACE PRESSURE GRADIENT IS OVER THE NE GULF OF
MEXICO PRODUCING 25-30 KT WINDS. A COLD FRONT EXTENDS S FROM THE
LOW CENTER TO THE SE CARIBBEAN ALONG 25N84W 20N85W. WIDELY
SCATTERED MODERATE CONVECTION IS E OF THE COLD FRONT OVER THE E
GULF OF MEXICO AND FLORIDA FROM 20N-32N E OF 84W. RADAR ALSO
SHOWS SOME EMBEDDED SEVERE THUNDERSTORM CELLS OVER S FLORIDA. IN
THE UPPER LEVELS...THE LEADING EDGE OF AN UPPER LEVEL TROUGH IS
OVER THE W GULF W OF 90W WHILE THE BACK SIDE OF AN UPPER LEVEL
RIDGE IS OVER THE E GULF. THESE FEATURES ARE PRODUCING SOUTHERLY
UPPER LEVEL FLOW OVER THE ENTIRE GULF. SIGNIFICANT UPPER LEVEL
MOISTURE IS OVER THE BAY OF CAMPECHE...AND OVER FLORIDA. STRONG
SUBSIDENCE IS OVER THE REMAINDER OF THE GULF ESPECIALLY OVER THE
NW GULF AND S TEXAS. EXPECT...THE LOW TO DEEPEN AND RACE TO THE
NORTH CAROLINA COAST IN 24 HOURS WITH A TRAILING COLD FRONT TO
THE NORTHERN BAHAMAS. ALSO EXPECT IN 24 HOURS NORTHERLY SURFACE
FLOW WITH COLD AIR ADVECTION TO DOMINATE THE ENTIRE GULF OF
MEXICO AND FLORIDA.

CARIBBEAN SEA...
AS OF 1500 UTC...A COLD FRONT IS OVER THE NW CARIBBEAN EXTENDING
FROM W CUBA TO N HONDURAS ALONG 22N84W 16N86W. SCATTERED
MODERATE CONVECTION IS E OF THE FRONT OVER W CUBA AND THE NW
CARIBBEAN FROM 20N-23N BETWEEN 81W-84W. STRONG ELY TRADEWINDS
CONTINUE ACROSS THE REMAINDER OF THE CARIBBEAN. STRONGEST WINDS
REMAIN NEAR THE COASTS OF COLOMBIA AND VENEZUELA. PATCHES OF
BROKEN LOW CLOUDS WITH ISOLATED SHOWERS ARE OVER THE LEEWARD
ISLANDS...AND OVER THE W CARIBBEAN AND CENTRAL AMERICA W OF 80W.
IN THE UPPER LEVELS...MOSTLY ZONAL FLOW IS OVER THE CARIBBEAN.
OUTSIDE OF THE NW CARIBBEAN...VERY STRONG SUBSIDENCE IS ACROSS
THE BASIN SUPPRESSING DEEP CONVECTION. EXPECT... THE COLD FRONT
TO EXTEND FROM E CUBA TO E HONDURAS IN 24 HOURS WITH CONVECTION.
ALSO EXPECT THE TRADEWINDS AND SHOWERS TO PERSIST OVER THE
LEEWARD ISLANDS AND PUERTO RICO OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...
A COLD FRONT IS OVER CENTRAL AND WESTERN ATLANTIC FROM 32N38W TO
28N42W 22N60W. A STATIONARY FRONT CONTINUES TO THE NORTHERN
BAHAMAS ALONG 23N70W 27N79W. SCATTERED MODERATE CONVECTION IS
OVER THE CENTRAL ATLANTIC E OF THE COLD FRONT FROM 26N-32N
BETWEEN 35W-41W. SCATTERED SHOWERS ARE WITHIN 30 NM OF THE
REMAINDER OF THE FRONTS. A 1018 MB HIGH IS OVER THE E ATLANTIC
NEAR 23N29W. A COLD FRONT IS FURTHER E ALONG 32N7W 25N15W
17N25W. SCATTERED SHOWERS ARE WITHIN 30 NM OF THE FRONT. IN THE
UPPER LEVELS...AN UPPER LEVEL RIDGE IS OVER THE W ATLANTIC W OF
60W. ZONAL FLOW IS OVER THE REMAINDER OF THE ATLANTIC. EXPECT...
THE COLD FRONT PRESENTLY IN THE GULF OF MEXICO TO BE OVER THE W
ATLANTIC FROM 32N74W TO E CUBA IN 24 HOURS WITH CONVECTION. ALSO
EXPECT THE FRONT OVER THE CENTRAL ATLANTIC TO MOVE E WITH
SHOWERS.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE.

$$
FORMOSA





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