[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 041800
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT SEP 04 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...

TROPICAL STORM EARL IS CENTERED NEAR 45.8N 63.2W AT 04/1800 UTC
OR ABOUT 25 NM S OF CHARLOTTETOWN PRINCE EDWARD ISLAND MOVING NE
AT 35 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 965 MB. MAXIMUM
SUSTAINED WIND SPEED IS 60 KT WITH GUSTS TO 75 KT. NUMEROUS
SHOWERS ARE FROM 44N-47N BETWEEN 61W-69W...INCLUDING FAR EASTERN
MAINE...AND PORTIONS OF THE EASTERN CANADIAN MARITIMES. SEE
LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS
MIATCPAT2/ WTNT32 KNHC AND THE FULL FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS.

THE REMNANT 1008 MB LOW OF GASTON IS CENTERED NEAR 16N46W MOVING
WNW AT 10 KT. THE LOW-LEVEL CENTER REMAINS EXPOSED ON SATELLITE
IMAGERY...HOWEVER CURVED BANDS OF CONVECTION SWIRL AROUND THE
LOW WITH MOST OF THE CONVECTION SHEARED TO THE WEST. SCATTERED
MODERATE CONVECTION IS LOCATED WITHIN 150 NM OF THE LOW CENTER
IN THE WESTERN SEMICIRCLE.

...TROPICAL WAVES...

TROPICAL WAVE IS OVER INTERIOR W AFRICA FROM 06N TO 14N ALONG
06W MOVING W AT 10 KT. A 1012 MB LOW IS CENTERED ALONG THE WAVE
AXIS NEAR 09N06W. HOVMOLLER DIAGRAM EXAMINATION AND UPPER AIR
TIME-SECTION ANALYSES INDICATE THIS WAVE PASSED NIAMEY NIGER
AROUND 03/2100 UTC. SCATTERED MODERATE TO STRONG CONVECTION IS
FROM 10N-13N BETWEEN 07W-11W.

TROPICAL WAVE EXTENDS FROM 18N19W TO A 1010 MB LOW CENTERED NEAR
14N22W THEN SSW TO 07N27W. THIS WAVE IS EMBEDDED WITHIN A BROAD
AREA OF LOW-LEVEL CYCLONIC FLOW OVER THE EASTERN TROPICAL ATLC
WITH SW MONSOONAL FLOW LOCATED S OF 10N THAT EXTENDS ALONG THE
WAVE AXIS TO 06N30W. SCATTERED MODERATE AND ISOLATED STRONG
CONVECTION IS WITHIN 240 NM W OF THE WAVE AXIS. SCATTERED
MODERATE AND ISOLATED STRONG CONVECTION MORE ASSOCIATED WITH THE
SW MONSOONAL FLOW IS OCCURRING FROM 02N-09N BETWEEN 25W-36W.

...ITCZ...

ITCZ AXIS EXTENDS ALONG 11N48W 08N59W 11N75W. ISOLATED MODERATE
CONVECTION IS FROM 08N-11N BETWEEN 42W-49W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL LONGWAVE TROUGH IS LOCATED OVER MUCH OF THE
EASTERN CONUS THAT DIPS TO 29N. EMBEDDED WITHIN THIS
TROUGHING...AN UPPER LEVEL SHORTWAVE TROUGH WITH AXIS ALONG 90W
IS OVER THE CENTRAL GULF WATERS. THE LONGWAVE TROUGH SUPPORTS A
COLD FRONT THAT EXTENDS ACROSS THE FLORIDA PANHANDLE AND ENTERS
THE GULF NEAR 30N86W THEN WESTWARD TO 29N90W OVER SE LOUISIANA
THEN TO THE TEXAS COAST NEAR 27N97W. THE SHORTWAVE TROUGH
SUPPORTS A PAIR OF SURFACE TROUGHS. ONE IS ANALYZED FROM 28N86W
TO 24N92W WITH SCATTERED SHOWERS AND TSTMS WITHIN 120 NM OF THE
TROUGH AXIS. THE OTHER SURFACE TROUGH IS ANALYZED ALONG 28N93W
23N96W TO 19N95W WITH SCATTERED SHOWERS AND TSTMS WITHIN 120 NM
OF THE MEXICO COAST S OF 25N AND OVER THE SW GULF S OF 24N W OF
92W. WHILE LOWER PRESSURE VALUES EXIST OVER THE SW GULF...GLOBAL
MODELS ARE INDICATING CYCLOGENESIS IS POSSIBLE OVER THE NEXT
12-24 HOURS. ELSEWHERE...OVER THE REMAINDER OF THE GULF E OF
90W...AN UPPER LEVEL ANTICYCLONE IS ANCHORED OVER FLORIDA
STRAITS NEAR 25N81W AND EXTENDS AN UPPER LEVEL RIDGE AXIS SW TO
THE YUCATAN CHANNEL. WIDELY SCATTERED SHOWERS ARE OCCURRING FROM
23N-26N BETWEEN 78W-85W.

CARIBBEAN SEA...
NE UPPER LEVEL FLOW IS NOTED ON WATER VAPOR IMAGERY W OF 70W ON
THE SOUTHERN PERIPHERY OF AN ANTICYCLONIC CIRCULATION CENTERED
OVER THE FLORIDA STRAITS AND W ATLC NEAR 25N81W. THIS IS
PROVIDING FOR AN UPPER LEVEL DIFFLUENT ENVIRONMENT ACROSS THE
WESTERN CARIBBEAN WHICH IN TURN IS ENHANCING CONVECTION FOCUSED
ALONG A SURFACE TROUGH ANALYZED FROM 10N75W TO 14N80W. SCATTERED
SHOWERS AND TSTMS ARE OCCURRING FROM 09N-15N BETWEEN 76W-83W.
OTHER CONVECTIVE ACTIVITY IS LOCATED IN THE VICINITY OF JAMAICA
WITH SCATTERED SHOWERS AND TSTMS FROM 15N-19N BETWEEN 75W-79W. E
OF 70W...AN UPPER LEVEL LOW IS CENTERED NEAR 16N64W AND
CONTINUES TO INTRODUCE MODERATELY DRY AIR OVER THE EASTERN
CARIBBEAN AND LESSER ANTILLES. HOWEVER...OVER THE FAR SE
CARIBBEAN THE UPPER LEVEL LOW IS ADVECTING MOISTURE NE WITH
ISOLATED SHOWERS S OF 13N E OF 66W.

ATLANTIC OCEAN...
AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER THE STRAITS OF
FLORIDA NEAR 25N81W AND EXTENDS AN UPPER LEVEL RIDGE AXIS NE TO
28N76W AND BEYOND 32N65W. THIS UPPER LEVEL RIDGE SUPPORTS A
SURFACE RIDGE ALONG 25N THAT ENCOMPASSES THE W ATLC ANCHORED BY
A 1018 MB HIGH CENTERED NEAR 26N67W. LOW- TO MID-LEVEL MOISTURE
COUPLED WITH INSTABILITY W OF 65W IS GENERATING AREAS OF
ISOLATED SHOWERS AND TSTMS N OF 20N W OF 65W. A SURFACE
TROUGH...THE REMNANTS OF FIONA...IS ANALYZED FROM 30N63W 35N63W
WITH SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 90 NM EITHER
SIDE OF THE TROUGH AXIS. UPPER LEVEL TROUGHING COVERS THE
CENTRAL ATLC WITH THE AXIS EXTENDING FROM AN UPPER LEVEL LOW
CENTERED OVER THE NE CARIBBEAN NEAR 16N64W TO ANOTHER UPPER
LEVEL LOW NEAR 33N53W. THE UPPER LOW IS GENERATING ISOLATED
SHOWERS FROM 20N-24N BETWEEN 58W-62W. ELSEWHERE ACROSS THE
REMAINDER OF THE CENTRAL AND EASTERN ATLC...A BROAD SURFACE
RIDGE DOMINATES N OF 22N E OF 60W ANCHORED BY A 1023 MB HIGH
CENTERED NEAR 32N35W.

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

$$
HUFFMAN



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