[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 200601
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...

AN UPPER LEVEL LOW IS CENTERED NEAR 24N54W WITH AN UPPER LEVEL
TROUGH AXIS ORIENTED N-NW TO S-SE ALONG 32N64W TO 13N52W. THIS
UPPER LEVEL FEATURE SUPPORTS A COMPLEX AREA OF SURFACE TROUGHING
ACROSS THE CENTRAL ATLC WITH A SURFACE TROUGH ANALYZED FROM
12N53W THROUGH A 1011 MB LOW NEAR 21N53W ALONG 27N53W TO BEYOND
32N50W AND WEAKER SURFACE TROUGH ANALYZED FROM 21N57W TO 24N62W.
THE DOMINANT EASTERLY SURFACE TROUGH REMAINS THE FOCUS FOR
POTENTIAL TROPICAL OR SUB-TROPICAL CYCLONE FORMATION WITH A
MEDIUM CHANCE DURING THE NEXT 48 HOURS. ACTIVITY IN THE VICINITY
IS ASSOCIATED MORE WITH THE UPPER RIDGE TO THE E RATHER THAN THE
LOW/TROUGH ITSELF.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA ENTERING THE E TROPICAL
ATLC NEAR 13N17W TO 10N19W. THE ITCZ AXIS EXTENDS FROM 10N19W
ALONG 7N27W 7N40W TO NEAR 6N50W. SCATTERED MODERATE/STRONG
CONVECTION IS FROM 3N-9N BETWEEN 20W-32W. CLUSTERS OF SCATTERED
MODERATE/STRONG CONVECTION ARE FROM 4N-7N BETWEEN 10W-20W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 2N-9N BETWEEN 32W-38W.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER RIDGE DOMINATES THE GULF ANCHORED IN THE E PACIFIC
REGION WITH THE UPPER RIDGE AXIS EXTENDING ACROSS S MEXICO NEAR
VERACRUZ TO OVER NE FLORIDA WITH DRY STABLE AIR ALOFT COVERING
THE ENTIRE GULF. A SURFACE RIDGE DOMINATES THE GULF ANCHORED IN
THE W ATLC EXTENDING AN AXIS SE CONUS ALONG 30N86W TO TUXPAN
MEXICO. RETURN FLOW IS DEVELOPING OVER THE NW GULF TONIGHT.
BROKEN LOW CLOUDS WITH SCATTERED SHOWERS ARE OVER THE NE GULF N
OF 27N TO OVER THE FLORIDA PANHANDLE BETWEEN 85W-88W LEAVING THE
REMAINDER OF THE GULF UNDER CLEAR SKIES TONIGHT. SURFACE RIDGE
WILL PERSIST THROUGH MON WITH RETURN FLOW OVER THE NW GULF. A
COLD FRONT WILL MOVE OFF THE TEXAS COAST LATE TUE AND EXTEND
FROM THE FLORIDA BIG BEND AREA TO VERACRUZ MEXICO BY WED EVENING
AND THEN E OF THE GULF THU.

CARIBBEAN SEA...
THE UPPER RIDGE OVER THE GULF OF MEXICO COVERS THE NW CARIBBEAN
N OF 16N W OF 80W. A WEAK INVERTED UPPER TROUGH EXTENDS FROM
JAMAICA TO NE NICARAGUA. A SECOND UPPER RIDGE COVERS THE
REMAINDER OF THE CARIBBEAN ANCHORED NEAR 15N71W. DRY STABLE AIR
ALOFT DOMINATES THE E CARIBBEAN E OF 75W WITH MOIST TROPICAL AIR
OVER THE W CARIBBEAN. CLUSTERS OF SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS DOT THE W CARIBBEAN S OF 20N BETWEEN 73W-83W
USHERED IN ON THE STRONG EASTERLY TRADE WINDS. THE MONSOON
TROUGH EXTENDS FROM COLOMBIA NEAR 10N75W ALONG 11N80W ACROSS
COSTA RICA INTO THE E PACIFIC REGION NEAR 10N85W. ISOLATED LOW
LEVEL FAST MOVING SHOWERS ARE POSSIBLE ACROSS THE SE CARIBBEAN S
OF 15N E OF 73W ALSO USHERED IN ON THE EASTERLY TRADE WINDS.
FRESH TO STRONG NE WINDS WILL PERSIST OVER THE N CARIBBEAN
THROUGH EARLY TUE.

ATLANTIC OCEAN...
A SURFACE RIDGE DOMINATES THE W ATLC EXTENDING INTO THE GULF OF
MEXICO ANCHORED BY A 1034 MB HIGH ABOUT 600 NM NE BERMUDA. A
SHEAR AXIS IS ANALYZED FROM 30N57W TO JUST E OF THE BAHAMA
ISLANDS NEAR 26N76W WITH ISOLATED SHOWERS POSSIBLE WITHIN 75 NM
NW OF THE SHEAR AXIS. THE ELONGATED UPPER LEVEL TROUGH/SURFACE
FEATURES IN THE SPECIAL FEATURES SECTION ABOVE IS TO THE E OF
THE SURFACE RIDGE...SEE ABOVE. A HIGHLY AMPLIFIED UPPER RIDGE IS
TO THE E OF THE SPECIAL FEATURES EXTENDING FROM NEAR 12N41W
ALONG 23N42W TO BEYOND 32N43W PROVIDING DIFFLUENCE ALOFT TO
GENERATE SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS
WITHIN 120/150 NM OF LINE FROM 14N47W TO 23N49W AND WITHIN 175
NM OF LINE FROM 22N51W TO BEYOND 32N46W. AN UPPER TROUGH
CONTINUES TO DIG S OVER THE E ATLC TO 15N E OF 30W SUPPORTING A
COLD FRONT N OF THE DISCUSSION AREA. THE REMAINDER OF THE E ATLC
IS DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1026 MB HIGH
CENTERED NEAR 34N37W. THE SHEAR LINE WILL MOVE LITTLE AND BECOME
DIFFUSE SUN. THE COMPLEX ELONGATED TROUGH WILL REMAIN STATIONARY
THROUGH MON BEFORE BEGINNING TO DRIFT NE TUE AND WED. A NEW COLD
FRONT WILL ENTER NW PORTIONS WED EVENING AND REACH FROM NEAR
28N65W TO FLORIDA KEYS LATE THU NIGHT.
0
FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
PAW





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