[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 230553
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU SEP 23 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 17.7N 29.6W AT 23/0300 UTC
OR ABOUT 335 NM WNW OF THE CAPE VERDE ISLANDS MOVING E AT 4 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM SUSTAINED
WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. SOME STRENGTHENING IS
FORECAST OVER THE NEXT 48 HOURS AS THE TROPICAL CYCLONE REMAINS
SOUTH OF AN EASTERN ATLC UPPER LEVEL TROUGH AND WITHIN A
RELATIVELY LOW VERTICAL WIND SHEAR ENVIRONMENT. ISOLATED
MODERATE CONVECTION IS FROM 16N-21N BETWEEN 26W-30W. SEE LATEST
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24
KNHC FOR MORE DETAILS.

TROPICAL WAVE EXTENDS FROM 10N71W TO 17N72W MOVING W AT 10-15
KT. A 1007 MB LOW IS ANALYZED ALONG THE WAVE AXIS CENTERED NEAR
13N72W. WHILE PREDOMINATELY NORTHEAST TO EASTERLY FLOW IS
OCCURRING AT THE SURFACE OVER THE EASTERN AND CENTRAL 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 WNW OVER THE WESTERN
CARIBBEAN SEA THE NEXT 24-36 HOURS. SCATTERED MODERATE AND
ISOLATED CONVECTION IS FROM 11N-17N BETWEEN 65W-75W.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM 10N23W TO 18N23W MOVING W AT 10-15
KT. THE WAVE CONTINUES MOVING WESTWARD AND IS COMING UNDER THE
INFLUENCE OF LOW-LEVEL SOUTHWESTERLY MONSOON FLOW FEEDING INTO
NEARBY T.S. LISA. ISOLATED MODERATE CONVECTION IS FROM 10N-15N
BETWEEN 24W-28W.

...ITCZ...

ITCZ AXIS IS ANALYZED ALONG 10N32W TO 11N63W. SCATTERED MODERATE
CONVECTION IS FROM 07N-11N BETWEEN 18W-22W...AND FROM 06N-12N
BETWEEN 34W-46W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL ANTICYCLONE IS CENTERED IN THE VICINITY OF THE
TEXAS BIG BEND REGION NEAR 29N102W AND EXTENDS UPPER LEVEL
RIDGING EASTWARD OVER THE WESTERN GULF TO 92W. THIS UPPER LEVEL
FEATURE IS PROVIDING STABLE NORTHERLY FLOW ALOFT OVER THE NW
GULF. A SECOND UPPER LEVEL RIDGE IMPACTS THE EASTERN GULF E OF
88W WHICH IS ANCHORED IN THE SW NORTH ATLC NEAR 21N76W. BETWEEN
BOTH THESE ANTICYCLONIC REGIMES...A NARROW UPPER LEVEL TROUGH IS
LOCATED OVER THE CENTRAL GULF BETWEEN 88W-92W WITH A TROUGH AXIS
EXTENDING FROM MOBILE BAY TO THE NW YUCATAN PENINSULA NEAR
20N90W. AT THE SURFACE...A RIDGE AXIS EXTENDS FROM THE W ATLC
ACROSS NORTHERN FLORIDA TO THE TEXAS GULF COAST NEAR BROWNSVILLE
AND IS PROVIDING MUCH OF THE GULF WITH 15-20 KT E TO SE WINDS.
ISOLATED SHOWERS AND TSTMS CONTINUE ADVECTING ACROSS THE CENTRAL
GULF WATERS FROM 22N-27N.

CARIBBEAN SEA...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED IN THE SW NORTH
ATLC NEAR 21N76W EXTENDS AN UPPER LEVEL RIDGE AXIS OVER EASTERN
CUBA TO THE NICARAGUA/HONDURAS BORDER NEAR 14N85W. EASTERLY
UPPER LEVEL FLOW TURNS NORTHERLY OVER THE NW CARIBBEAN AND IS
ADVECTING MOISTURE OVER MUCH OF THE WESTERN CARIBBEAN AND CUBA
THIS EVENING. ATMOSPHERIC INSTABILITY AND CONVERGENT LOW-LEVEL
TRADEWINDS ARE GENERATING A LARGE AREA OF SCATTERED SHOWERS AND
TSTMS FROM 11N-23N BETWEEN 76W-84W...INCLUDING INTERIOR PORTIONS
OF CENTRAL CUBA. FARTHER EAST OVER THE CENTRAL CARIBBEAN...THE
TROPICAL WAVE ALONG 72W AND ASSOCIATED 1007 MB LOW PRESSURE
CENTERED NEAR 13N72W IS HIGHLIGHTED IN THE SPECIAL FEATURES
SECTION ABOVE. THIS AREA IS LOCATED ON THE SOUTHERN EXTENT OF AN
UPPER LEVEL LOW CENTERED NORTH OF PUERTO RICO NEAR 19N66W. THE
INVERTED UPPER LEVEL TROUGH AXIS EXTENDS FROM THE LOW CENTER SW
TO 12N72W. UPPER LEVEL LIFT ASSOCIATED WITH THE TROUGHING AND
STRONG EASTERLY TRADES OVER THE EASTERN CARIBBEAN ARE GENERATING
AN AREA OF SCATTERED SHOWERS AND TSTMS FROM 11N-17N BETWEEN
63W-74W.

ATLANTIC OCEAN...
AN UPPER LEVEL RIDGE AXIS EXTENDS ACROSS THE W ATLC FROM CENTRAL
CUBA NEAR 21N76W NE TO 28N67W. THIS UPPER LEVEL RIDGE IS DRAWING
TROPICAL MOISTURE NORTHWARD ACROSS CUBA AND THE BAHAMAS TO NEAR
BERMUDA. ISOLATED SHOWERS AND TSTMS ARE PRIMARILY OVER THE
STRAITS OF FLORIDA REMAINING S OF 25N AND W OF 77W. FARTHER
NORTHEAST...ISOLATED SHOWERS STREAM WESTWARD FROM 23N-29N W OF
68W. THE REMAINDER OF THE W ATLC IS UNDER THE INFLUENCE OF A
BROAD SURFACE RIDGE LOCATED W OF 50W AND EXTENDING ACROSS THE
FLORIDA PENINSULA INTO THE GULF OF MEXICO ANCHORED BY A 1027 MB
HIGH CENTERED NEAR 37N54W. A MID-LEVEL SHORTWAVE TROUGH IS
LOCATED NORTH OF THE DISCUSSION AREA ACROSS THE CENTRAL ATLC
WITH AXIS EXTENDING FROM 38N34W TO 32N39W TO 30N43W. THIS
TROUGHING SUPPORTS THE REMNANT 1010 MB LOW OF JULIA CENTERED
NEAR 33N38W AND A SURFACE TROUGH ANALYZED FROM THE LOW ALONG
30N37W TO 27N40W TO 25N50W. SCATTERED MODERATE CONVECTION IS
FROM 32N-36N BETWEEN 35W-38W...WHILE ISOLATED SHOWERS LINGER
WITHIN 90 NM EITHER SIDE OF THE SURFACE TROUGH AXIS. ELSEWHERE
OVER THE REMAINDER OF THE EASTERN ATLC...AN UPPER LEVEL TROUGH
AXIS EXTENDS THROUGH 32N23W TO 20N28W. MOIST SOUTHWESTERLY FLOW
ALOFT EAST OF THE TROUGH AXIS IS GENERATING ISOLATED SHOWERS
FROM 20N-32N BETWEEN 18W-26W.

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

$$
HUFFMAN




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