[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201737
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SUN NOV 20 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 1010 MB LOW IS CENTERED NEAR 22N54W. A SURFACE TROUGH EXTENDS
FROM 30N52W TO THE LOW CENTER TO 17N53W. THE LOW IS SHOWING
SIGNS OF BEING A SUB-TROPICAL SYSTEM WITH CONVECTION WELL NE OF
THE LOW CENTER AND STRONGEST WINDS WELL AWAY FROM THE CENTER.
WIDELY SCATTERED MODERATE CONVECTION IS FROM 21N-30N BETWEEN
45W-53W. CONTINUED SLOW DEVELOPMENT OF THIS DISTURBANCE
IS POSSIBLE DURING THE NEXT DAY OR TWO AS IT MOVES SLOWLY
NORTHWARD INTO A REGION OF MORE FAVORABLE UPPER-LEVEL WINDS.
THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A SUBTROPICAL OR
TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA ENTERING THE E TROPICAL
ATLC NEAR 11N15W AND CONTINUING TO 8N19W. THE ITCZ AXIS EXTENDS
FROM 8N19W TO 7N32W TO 4N38W TO SOUTH AMERICA NEAR 6N54W. WIDELY
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS FROM 2N-10N
BETWEEN 13W-34W. ISOLATED MODERATE CONVECTION IS FROM 7N-9N
BETWEEN 43W-50W.

...DISCUSSION...

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 S FLORIDA AND THE STRAITS OF FLORIDA S
OF 26N MOVING W. MORE SHOWERS ARE OVER THE FLORIDA PANHANDLE AND
THE NE GULF FROM 28N-31N BETWEEN 84W-87W MOVING NE. THE
REMAINDER OF GULF HAS FAIR WEATHER. IN THE UPPER LEVELS...AN
UPPER LEVEL RIDGE IS OVER THE GULF WITH AXIS FROM LOUISIANA TO
THE THE SW BAY OF CAMPECHE. STRONG SUBSIDENCE COVERS THE ENTIRE
GULF. EXPECT CONTINUES SHOWERS OVER S FLORIDA...THE STRAITS OF
FLORIDA...AND THE BAY OF CAMPECHE OVER THE NEXT 24 HOURS DUE TO
TROPICAL MOISTURE ADVECTING OVER THOSE AREAS.

CARIBBEAN SEA...
10-25 KT TRADEWINDS ARE OVER THE CARIBBEAN SEA WITH STRONGEST
WINDS W OF 70W. SCATTERED SHOWERS AND RAIN IS OVER THE NW
CARIBBEAN AND THE COASTAL REGIONS OF CENTRAL AMERICA N OF COSTA
RICA MOVING W. MORE SHOWERS ARE OVER JAMAICA...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 7N-12N BETWEEN 76W-84W. IN THE UPPER LEVELS... THE BASE
OF AN UPPER LEVEL TROUGH IS OVER THE CARIBBEAN SEA. UPPER LEVEL
MOISTURE IS OVER THE SW CARIBBEAN SEA AND CENTRAL AMERICA E OF
88W. STRONG SUBSIDENCE IS OVER THE REMAINDER OF THE CARIBBEAN.
EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...
A 1034 MB HIGH IS CENTERED OVER THE CENTRAL ATLANTIC NEAR
40N50W. A SURFACE RIDGE AXIS EXTENDS SW FROM THE HIGH CENTER TO
N FLORIDA. SCATTERED SHOWERS ARE NOTED OVER THE BAHAMAS FROM
24N-28N W OF 74W MOVING W. THE SPECIAL FEATURE IS THE DOMINATE
WEATHER PRODUCER IN THE CENTRAL ATLANTIC. SEE ABOVE. IN THE E
ATLANTIC A SURFACE RIDGE AXIS ALSO EXTENDS SE FROM THE CENTRAL
ATLANTIC HIGH TO THE CANARY ISLANDS. AN UPPER LEVEL TROUGH IS
OVER THE CENTRAL ATLANTIC N OF 20N BETWEEN 50W-70W ENHANCING THE
SPECIAL FEATURE LOW.

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

$$
FORMOSA







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