[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211726
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST MON NOV 21 2011

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...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1715 UTC.

...SPECIAL FEATURES...

A 1007 MB LOW PRESSURE CENTER IS NEAR 27N52W. A SURFACE TROUGH
EXTENDS SW FROM THE LOW CENTER TO 20N60W. SCATTERED MODERATE
CONVECTION IS NE OF THE CENTER FROM 27N-32N BETWEEN 47W-52W.
SCATTERED RAINSHOWERS ARE ALSO WITHIN 30 NM OF THE LOW AND
TROUGH AXIS. GALE-FORCE WINDS ARE WITHIN 150 NM NW QUADRANT.
IT IS POSSIBLE THAT THE LOW CENTER WILL GRADUALLY ACQUIRE MORE
SUBTROPICAL CHARACTERISTICS WITHIN THE NEXT 48 HOURS AND BECOME
A SUBTROPICAL CYCLONE BEFORE IT MOVES NE OVER COOLER WATERS.
ADDITIONAL INFORMATION ON THIS LARGE WEATHER SYSTEM CAN BE FOUND
IN HIGH SEAS FORECASTS ISSUED BY THE NATIONAL WEATHER SERVICE...
UNDER AWIPS HEADER NFDHSFAT1 AND WMO HEADER FZNT01 KWBC.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA ENTERING THE E TROPICAL
ATLC NEAR 7N12W AND CONTINUING A SHORT WAY TO 6N14W. THE ITCZ
AXIS EXTENDS FROM 6N14W TO 3N25W TO 7N40W TO SOUTH AMERICA NEAR
7N58W. WIDELY SCATTERED MODERATE ISOLATED STRONG CONVECTION IS
FROM 2N-10N BETWEEN 14W-20W. ISOLATED MODERATE CONVECTION IS
FROM 2N-4N BETWEEN 20W-33W.

...DISCUSSION...

THE GULF OF MEXICO...
SURFACE RIDGING IS OVER THE GULF OF MEXICO WITH AXIS ALONG 30N.
10-15 KT E-SE WINDS DOMINATE OVER THE GULF. SCATTERED SHOWERS
ARE NOTED ON RADAR OVER THE EAST COAST OF FLORIDA S OF MELBOURNE
FLORIDA TO THE STRAITS OF FLORIDA MOVING W. THE GULF OF MEXICO
HAS MOSTLY FAIR WEATHER ELSEWHERE. IN THE UPPER LEVELS...AN
UPPER LEVEL RIDGE IS OVER THE GULF WITH AXIS FROM THE SW BAY OF
CAMPECHE TO N FLORIDA. STRONG SUBSIDENCE COVERS THE ENTIRE GULF.
EXPECT SHOWERS OVER SE FLORIDA AND THE STRAITS OF FLORIDA TO
DISSIPATE OVER THE NEXT 24 HOURS. ALSO EXPECT A COLD FRONT TO BE
INLAND OVER SE TEXAS IN 24 HOURS WITH CONVECTION.

THE CARIBBEAN SEA...
10-25 KT TRADEWINDS ARE OVER THE CARIBBEAN SEA WITH STRONGEST
WINDS W OF 70W. SCATTERED SHOWERS THE COASTAL REGIONS OF CENTRAL
AMERICA N OF COSTA RICA TO BELIZE MOVING W. MORE SHOWERS ARE
OVER HISPANIOLA...PUERTO RICO...THE LEEWARD ISLANDS...THE
WINDWARD ISLANDS...AND ALONG THE COAST OF N VENEZUELA. A MONSOON
TROUGH EXTENDS FROM N COLOMBIA TO COSTA RICA ALONG 10N. ISOLATED
MODERATE CONVECTION IS FROM 9N-12N BETWEEN 77W-84W. IN THE UPPER
LEVELS...THE BASE OF AN UPPER LEVEL TROUGH IS OVER THE CARIBBEAN
SEA. UPPER LEVEL MOISTURE IS S OF 12N OVER THE S CARIBBEAN
SEA...SW CENTRAL AMERICA...AND NORTHERN SOUTH AMERICA. STRONG
SUBSIDENCE IS OVER THE REMAINDER OF THE CARIBBEAN. EXPECT LITTLE
CHANGE OVER THE NEXT 24 HOURS.

THE ATLANTIC OCEAN...
A 1025 MB HIGH IS CENTERED OVER THE W ATLANTIC NEAR 33N76W. A
SURFACE RIDGE AXIS EXTENDS SW FROM THE HIGH CENTER TO N FLORIDA.
SCATTERED SHOWERS ARE NOTED N OF THE BAHAMAS FROM 27N-29N W OF
77W MOVING W TO FLORIDA. THE SPECIAL FEATURE IS THE DOMINATE
WEATHER PRODUCER IN THE CENTRAL ATLANTIC. SEE ABOVE. A LARGE
1033 MB HIGH IS CENTERED OVER THE E ATLANTIC NEAR 39N30W.
A SURFACE RIDGE AXIS EXTENDS S FROM THIS HIGH TO 20N27W. AN
UPPER LEVEL TROUGH IS OVER THE CENTRAL ATLANTIC N OF 20N BETWEEN
50W-80W ENHANCING THE SPECIAL FEATURE LOW.

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

$$
FORMOSA





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