[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 220552
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED SEP 22 2010

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...

TROPICAL STORM LISA IS CENTERED NEAR 18.2N 31.3W AT 22/0300 UTC
OR ABOUT 435 NM WNW OF THE CAPE VERDE ISLANDS MOVING NE AT 2 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1002 MB. MAXIMUM SUSTAINED
WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. GRADUAL STRENGTHENING
IS FORECAST OVER THE NEXT 48 HOURS AS THE TROPICAL CYCLONE
REMAINS SOUTH OF AN EASTERN ATLC TROUGH IN A MINIMAL VERTICAL
WIND SHEAR ENVIRONMENT. ISOLATED MODERATE CONVECTION IS WITHIN
150 NM OF THE CENTER. SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.

TROPICAL WAVE EXTENDS FROM 07N65W TO 18N65W MOVING W AT 15 KT. A
1009 MB LOW IS ANALYZED ALONG THE WAVE AXIS CENTERED NEAR
12N65W. WHILE PREDOMINATELY NORTHEAST TO EASTERLY FLOW IS
OCCURRING AT THE SURFACE OVER THE EASTERN CARIBBEAN SEA N OF THE
LOW CENTER...MODEL GUIDANCE INDICATES A MID-LEVEL...700 MB...
CIRCULATION COINCIDES WITH THE SURFACE LOW. THESE FEATURES ARE
FORECAST TO TRACK OVER FAR SOUTHERN CARIBBEAN SEA AND THE ABC
ISLANDS OVER THE NEXT 24 HOURS. CONVECTION REMAINS DISORGANIZED
WITH WIDELY SCATTERED MODERATE CONVECTION OVER A LARGE PORTION
OF THE CENTRAL CARIBBEAN SEA FROM 08N-18N BETWEEN 64W-75W.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 10N20W TO 22N20W MOVING W AT 10-15
KT. A 1008 MB LOW IS ANALYZED ALONG THE WAVE AXIS NEAR 17N20W.
CIMSS WAVETRAK MODEL GUIDANCE INDICATES AN AREA OF MAXIMUM 850
MB RELATIVE VORTICITY IS ASSOCIATED WITH THE WAVE AXIS LOCATED
OFF THE W AFRICA COAST FROM 08N-20N E OF 23W. SCATTERED MODERATE
AND ISOLATED STRONG CONVECTION IS FROM 15N-20N BETWEEN 19W-22W.

...ITCZ...

A MONSOONAL TROUGH IS ANALYZED FROM SW OF T.S. LISA NEAR 15N34W
TO 11N46W. THE ITCZ AXIS THEN RESUMES NEAR 11N46W AND EXTENDS TO
12N60W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS
FROM 04N-13N BETWEEN 20W-25W...AND FROM 08N-13N BETWEEN 44W-58W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE EXTENDS ACROSS MUCH OF THE GULF OF MEXICO W
OF 88W STEMMING FROM AN UPPER LEVEL ANTICYCLONE CENTERED OVER
NORTHERN MEXICO NEAR 28N105W. THIS ANTICYCLONE IS PROVIDING
STABLE NORTHERLY FLOW ALOFT OVER THE WESTERN GULF WHILE
SUPPORTING BROAD SURFACE RIDGING. THE SURFACE RIDGE AXIS EXTENDS
FROM A 1023 MB HIGH CENTERED IN THE W ATLC OFFSHORE OF THE
DELMARVA NEAR 37N71W...ACROSS NORTHERN FLORIDA TO THE TEXAS GULF
COAST NEAR CORPUS CHRISTI. HOWEVER...AN UPPER LEVEL SHORTWAVE
TROUGH IS LOCATED OVER THE NE GULF AND IS BECOMING EMBEDDED
WITHIN A STRONGER UPPER LEVEL TROUGH PRESENT OVER THE FAR W ATLC
AND FLORIDA PENINSULA. THIS MID-LEVEL TROUGHING IS GENERATING AN
AREA OF ISOLATED SHOWERS FROM 22N-29N BETWEEN 83W-88W. THE
REMAINDER OF THE GULF IS UNDER THE INFLUENCE OF E-SE SURFACE
WINDS WITH ISOLATED SHOWERS EMBEDDED WITHIN THAT FLOW FROM
21N-28N W OF 90W. ALSO A FEW ISOLATED SHOWERS AND TSTMS ARE
LOCATED IN THE EASTERN BAY OF CAMPECHE AND OVER SOUTHERN MEXICO
S OF 21N BETWEEN 88W-95W.

CARIBBEAN SEA...
AN UPPER LEVEL TROUGH EXTENDS FROM THE FAR W ATLC ACROSS WESTERN
CUBA TO NEAR 17N84W. DRY AIR ALOFT ASSOCIATED WITH THE TROUGHING
IS PROVIDING MOSTLY FAIR CONDITIONS OVER CUBA...HOWEVER WITH THE
TROUGH AXIS EXTENDING OVER THE NW CARIBBEAN WATERS...ISOLATED
SHOWERS ARE FROM 17N-23N BETWEEN 78W-84W. FARTHER EAST...AN
UPPER LEVEL RIDGE AXIS EXTENDS FROM THE CENTRAL ATLC NEAR 27N60W
TO 22N70W AND INTO THE CENTRAL CARIBBEAN TO NEAR 13N80W. THIS
RIDGE AXIS IS PROVIDING AN OVERALL UPPER LEVEL DIFFLUENT
ENVIRONMENT AND ALONG WITH THE TROPICAL WAVE MOVING WESTWARD IN
THE EASTERN CARIBBEAN IS PRODUCING A LARGE AREA OF SCATTERED
SHOWERS AND ISOLATED TSTMS FROM NORTHERN PORTIONS OF VENEZUELA
TO 18N BETWEEN 60W-77W. WATER VAPOR IMAGERY CONTINUES TO SHOW
MOISTURE ADVECTING NORTHWESTWARD OVER HISPANIOLA AND THE TURKS
AND CAICOS ISLANDS PRODUCING ISOLATED SHOWERS FROM 18N-24N
BETWEEN 68W-77W. FINALLY...ISOLATED SHOWERS AND TSTMS ARE
OCCURRING OVER THE SW CARIBBEAN S OF 12N AND PORTIONS OF EASTERN
PANAMA.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH AXIS EXTENDS ACROSS THE FAR W ATLC AND
FLORIDA PENINSULA FROM 32N77W TO WESTERN CUBA NEAR 23N82W AND
INTO THE NW CARIBBEAN SEA. EAST OF THE UPPER LEVEL TROUGH
AXIS...ADVECTION OF MID-LEVEL MOISTURE FROM THE EASTERN
CARIBBEAN SEA IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS
OVER THE SE BAHAMAS AND TURKS AND CAICOS ISLANDS FROM 20N-24N
BETWEEN 68W-76W. THE REMAINDER OF THE W ATLC FALLS UNDER THE
INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1023 MB HIGH CENTERED
NORTH OF THE AREA NEAR 37N71W. ISOLATED SHOWERS MOVE WESTWARD ON
EASTERLY WINDS OF 10-20 KT FROM 25N-30N W OF 65W. ELSEWHERE
ACROSS THE CENTRAL AND EASTERN ATLC...A WEAK SURFACE RIDGE
EXTENDS FROM NW OF T.S. LISA NEAR 32N32W TO 25N50W AND IS
SUPPORTED ALOFT BY A LARGE UPPER LEVEL ANTICYCLONE CENTERED NEAR
29N47W. OVER THE FAR EASTERN ATLC...AN UPPER LEVEL TROUGH
CONTINUES TO DIP TO 20N AND REMAIN E OF 32W.

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

$$
HUFFMAN


WWWW
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