[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 092342
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED MAY 09 2012

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 13N17W TO
05N25W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
05N25W TO 02N30W TO THE EQUATOR NEAR 41W. SCATTERED MODERATE AND
ISOLATED STRONG CONVECTION IS FROM 02N-07N BETWEEN 17W-22W.
SCATTERED MODERATE CONVECTION IS FROM 02N-08N BETWEEN 08W-13W.

...DISCUSSION...

GULF OF MEXICO...
WEAK UPPER LEVEL RIDGING IS OVER THE GULF BASIN THIS EVENING
WITH A RIDGE AXIS EXTENDING FROM THE SW NORTH ATLC NEAR 32N74W
OVER THE SOUTHERN FLORIDA PENINSULA TO OVER THE YUCATAN
PENINSULA NEAR 18N90W. TO THE NORTH...AN UPPER LEVEL TROUGH IS
SWEEPING ACROSS THE GREAT LAKES REGION AND OHIO RIVER VALLEY
EXTENDING A TROUGH AXIS TO THE ARKLATEX REGION. A MID-LEVEL
SHORTWAVE TROUGH IS FOUND NEAR THE BASE OF THIS TROUGH OVER
LOUISIANA AND IS SUPPORTING A COLD FRONT EXTENDING FROM THE
FLORIDA PANHANDLE NEAR 31N87W INTO THE NORTH-CENTRAL GULF ALONG
28N90W TO 27N93W WHERE THE FRONT BECOMING STATIONARY TO THE NE
MEXICO COAST NEAR 24N98W. GIVEN THE FAVORABLE MIDDLE TO UPPER
LEVEL SUPPORT IS PRIMARILY N OF 30N...SCATTERED SHOWERS AND
ISOLATED TSTMS ARE OCCURRING N OF 29N WITHIN 60 NM EITHER SIDE
OF THE FRONT. A FEW ISOLATED SHOWERS AND TSTMS PRECEDE THE FRONT
OVER THE EASTERN GULF WATERS FROM 25N-29N E OF 85W TO THE
FLORIDA PENINSULA. FARTHER SW...A SURFACE TROUGH IS ANALYZED
FROM THE STATIONARY FRONT NEAR 25N97W SOUTHWARD TO 20N96W.
LOW-LEVEL MOISTURE CONVERGENCE COUPLED WITH DIFFLUENT FLOW ALOFT
IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS FROM 20N-26N
W OF 91W TO THE SURFACE TROUGH AXIS. THE COLD FRONT IS FORECAST
TO SLIDE EASTWARD THROUGH THURSDAY CROSSING THE FLORIDA
PENINSULA LATE THURSDAY AND CLEARING EAST OF THE BASIN BY
FRIDAY. WEAK SURFACE RIDGING IS EXPECTED TO BUILD OVER THE GULF
BY FRIDAY WITH EAST TO SOUTHEAST WINDS BECOMING RE-ESTABLISHED
THROUGH THE UPCOMING WEEKEND.

CARIBBEAN SEA...
AN UPPER LEVEL TROUGH IS OVER THE WESTERN CARIBBEAN WITH AXIS
EXTENDING FROM THE SW NORTH ATLC NEAR 24N73W TO A BASE NEAR
11N76W. WEST OF THE TROUGH AXIS DRY AND STABLE NW FLOW ALOFT IS
NOTED ON WATER VAPOR IMAGERY WITH CLEAR SKIES AND FAIR
CONDITIONS OVER MUCH OF THE NW CARIBBEAN THIS EVENING. EAST OF
THE TROUGH AXIS...MOIST SOUTHWESTERLY FLOW DOMINATES WITH MIDDLE
TO UPPER LEVEL MOISTURE ADVECTING NORTHEASTWARD FROM NORTHERN
SOUTH AMERICA OVER THE EASTERN CARIBBEAN AND INTO THE CENTRAL
ATLC. A SURFACE TROUGH IS ANALYZED FROM SE PUERTO RICO NEAR
18N66W TO NW VENEZUELA NEAR 11N70W PROVIDING FOCUS FOR WIDELY
SCATTERED SHOWERS AND ISOLATED TSTMS PRIMARILY EAST OF THE
TROUGH AXIS...INCLUDING THE LESSER ANTILLES AND PORTIONS OF NE
VENEZUELA. EASTERLY FLOW CONTINUES ACROSS MUCH OF THE BASIN...
HOWEVER REMAINS FAIRLY LIGHT IN THE RANGE OF 10 TO 15 KT.

ATLANTIC OCEAN...
UPPER LEVEL RIDGING EXTENDS OVER THE SW NORTH ATLC W OF 72W WITH
A RIDGE AXIS FROM 32N74W TO OVER THE SOUTHERN FLORIDA PENINSULA
NEAR 25N81W. THIS UPPER LEVEL RIDGING IS PROVIDING MUCH OF THE
SW NORTH ATLC WITH TRANQUIL CONDITIONS THIS EVENING...HOWEVER A
FEW ISOLATED SHOWERS AND TSTMS ARE OCCURRING OFFSHORE OF THE
FLORIDA PENINSULA FROM 24N-29N W OF 78W. THIS RIDGING IS
FORECAST TO ERODE OVER THE NEXT 24 HOURS AS AN UPPER LEVEL
TROUGH OVER THE GREAT LAKES REGION AND OHIO RIVER VALLEY MOVES
EASTWARD. THIS TROUGHING SUPPORTS A COLD FRONT CURRENTLY
ANALYZED FROM THE DELMARVA REGION SOUTHWEST ACROSS CENTRAL NORTH
CAROLINA...SOUTH CAROLINA...AND GEORGIA. NUMEROUS SHOWERS AND
TSTMS ARE MOVING OFF THE COAST THIS EVENING AND WILL CONTINUE TO
PROGRESS EASTWARD INTO THE SW NORTH ATLC COASTAL AND OFFSHORE
WATERS. FARTHER EAST...AN UPPER LEVEL SHORTWAVE TROUGH CENTERED
IN THE VICINITY OF 30N69W CONTINUES TO LIFT NORTHWARD AND
SUPPORTS A WEAK 1014 MB LOW CENTERED NEAR 31N69W. A DISSIPATING
STATIONARY FRONT EXTENDS FROM 30N67W TO 28N70W TO 28N73W WITH
ISOLATED SHOWERS OCCURRING WITHIN 30 NM EITHER SIDE OF THE
FRONT. THE REMAINDER OF THE WESTERN ATLC BETWEEN 50W-68W IS
UNDER THE INFLUENCE OF A WEAK SURFACE RIDGING WITH A RIDGE AXIS
EXTENDING TO 20N ALONG 59W. UPPER LEVEL TROUGHING COVERS MUCH OF
THE EASTERN ATLC N OF 20N AND THIS TROUGHING SUPPORTS A COLD
FRONT ANALYZED INTO THE DISCUSSION AREA NEAR 32N30W THAT EXTENDS
SOUTHWESTWARD ALONG 24N40W TO 23N50W THEN WESTWARD TO 23N58W.
ISOLATED SHOWERS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE
FRONT E OF 46W. ALOFT...SOUTHWESTERLY FLOW CONTINUES TO ADVECT A
360 NM WIDE SWATH OF MIDDLE TO UPPER LEVEL MOISTURE FROM THE
EASTERN CARIBBEAN SEA TO BEYOND 32N24W. ISOLATED SHOWERS ARE
POSSIBLE IN THIS AREA ESPECIALLY AS THE COLD FRONT CONTINUES TO
SLIDE EAST-SOUTHEASTWARD OVER THE NEXT 24 TO 36 HOURS.
FINALLY...A LARGE AREA OF SAHARAN DUST COVERS A LARGE PORTION OF
THE TROPICAL EASTERN ATLC FROM 06N-21N E OF 50W. MUCH OF THIS
AREA ON SATELLITE IMAGERY IS UNDER CLEAR SKIES AND STABLE
CONDITIONS DUE TO THE SUSPENDED DUST PARTICLES.

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

$$
HUFFMAN



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