[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 291752
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI OCT 29 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 SHARY IS CENTERED NEAR 30.2N 65.8W AT 29/1800 UTC
OR ABOUT 135 NM SSW OF BERMUDA MOVING NNE AT 10 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WIND
SPEED IS 50 KT WITH GUSTS TO 60 KT. SCATTERED MODERATE
CONVECTION IS LOCATED 180 NM FROM THE CENTER WITHIN THE SOUTHERN
SEMICIRCLE. ELSEWHERE ISOLATED SHOWERS ARE WITHIN 90 NM EITHER
SIDE OF A LINE FROM 36N64W TO 24N72W. THIS AREA OF PRECIPITATION
IS LOCATED WITHIN A MARGINAL UPPER LEVEL DIFFLUENT ZONE WEST OF
AN UPPER LEVEL TROUGH AXIS THAT EXTENDS FROM 31N64W SW INTO THE
WESTERN CARIBBEAN SEA NEAR 16N81W. SEE THE LATEST NHC
INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT5/
WTNT35 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS.

A TROPICAL WAVE EXTENDS FROM 05N54W TO 15N56W MOVING WNW AT
15-20 KT. A 1005 MB LOW IS POSITIONED ALONG THE WAVE AXIS NEAR
09N56 AND CONTINUES TO PROVIDE LOW-LEVEL FOCUS FOR NUMEROUS
MODERATE AND SCATTERED STRONG CONVECTION FROM 09N-13N BETWEEN
52W-59W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS
ELSEWHERE FROM 06N-16N BETWEEN 50W-60W. ENHANCEMENT OF THE
STRONGER ONGOING CONVECTION IS DUE TO UPPER LEVEL DIFFLUENCE
PROVIDED BY A BROAD UPPER LEVEL ANTICYCLONE CENTERED NEAR 11N51W.

...ITCZ...

ITCZ AXIS IS ANALYZED ALONG 07N11W 09N22W 05N33W 09N54W. A
SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ AND EXTENDS FROM
07N23W TO 17N19W. THIS SURFACE TROUGH AXIS WAS DEPICTED ON AN
EARLY MORNING ASCAT PASS AROUND 29/1124 UTC. ISOLATED MODERATE
CONVECTION IS WITHIN 150 NM EAST AND 90 NM WEST OF THE TROUGH
AXIS S OF 14N. THIS CONVECTION IS LIKELY ENHANCED DUE TO AN
UPPER LEVEL TROUGH WITH AXIS ALONG 25W. ELSEWHERE...SCATTERED
MODERATE CONVECTION IS FROM 06N-12N BETWEEN 13W-20W...AND FROM
03N-07N BETWEEN 24W-29W...AND WITHIN 240 NM NORTH OF THE AXIS
BETWEEN 29W-46W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL LONGWAVE TROUGH EXTENDS ALONG THE EASTERN U.S.
COAST FROM THE MID-ATLC STATES SOUTHWESTWARD OVER THE NE GULF TO
26N90W. THIS UPPER LEVEL TROUGHING SUPPORTS A COLD FRONT
ANALYZED FROM THE W ATLC ACROSS THE CENTRAL FLORIDA PENINSULA
AND INTO THE GULF NEAR FORT MYERS THEN SW ALONG 24N90W TO THE
EASTERN MEXICO COAST NEAR 20N96W. ISOLATED SHOWERS AND TSTMS ARE
WITHIN 60 NM EITHER SIDE OF THE COLD FRONT. EAST OF THE COLD
FRONT...MOSTLY FAIR CONDITIONS PREVAIL UNDER LIGHT NE SURFACE
WINDS AND A DRY AND SUBSIDENT UPPER LEVEL RIDGE AXIS ACROSS THE
SE GULF AND STRAITS OF FLORIDA. WEST OF THE COLD FRONT...STRONG
NORTHERLY WINDS ARE FORECAST THROUGH EARLY SATURDAY WITH NW TO N
WINDS REACHING GALE FORCE AS THE FRONT BEGINS TO STALL AND
DISSIPATE THROUGH LATE SATURDAY.

CARIBBEAN SEA...
BROAD SCALE UPPER LEVEL TROUGHING IS LOCATED ACROSS MUCH OF THE
CARIBBEAN BASIN WITH AXIS EXTENDING FROM AN ELONGATED UPPER
LEVEL LOW CENTERED IN THE SW NORTH ATLC NEAR 24N69W THROUGH THE
WINDWARD PASSAGE TO 15N81W. WATER VAPOR IMAGERY NOTES THAT THE
AIRMASS ASSOCIATED WITH THE UPPER LEVEL LOW IS MOSTLY DRY AND
STABLE...HOWEVER...A STREAM OF MID-LEVEL MOISTURE IS NOTED
AROUND THE WESTERN AND SOUTHERN PERIPHERY OF THE BASE OF THE
TROUGH PROVIDING ISOLATED SHOWERS AND TSTMS OVER THE GULF OF
HONDURAS...AND PORTIONS OF INLAND HONDURAS...AS WELL AS THE SW
CARIBBEAN S OF 12N. MOIST SW FLOW ALOFT IS LOCATED EAST OF THE
UPPER LEVEL TROUGH AXIS AND IS GENERATING ISOLATED SHOWERS N OF
14N BETWEEN 65W-80W. FARTHER EAST...AS THE TROPICAL WAVE AND
ASSOCIATED AREA OF LOWER PRESSURE ALONG 56W CONTINUES TRACKING
WEST-NORTHWESTWARD OVER THE NEXT FEW DAYS...LOCALLY HEAVY
RAINFALL AND STRONG GUSTY WINDS ARE EXPECTED TO IMPACT THE
WINDWARD ISLANDS AND NORTHERN PORTIONS OF VENEZUELA THROUGH THE
WEEKEND.

ATLANTIC OCEAN...
TROPICAL STORM SHARY AND THE TROPICAL WAVE IN THE TROPICAL ATLC
ARE THE PRIMARY CONCERNS IN THE ATLC BASIN THIS AFTERNOON...SEE
SPECIAL FEATURES ABOVE. THE UPPER LEVEL TROUGH THAT EXTENDS
ALONG THE EASTERN U.S. INTO THE NE GULF OF MEXICO SUPPORTS A
COLD FRONT THAT ENTERS THE REGION NEAR 32N74W TO THE FLORIDA
PENINSULA NEAR JUPITER. SCATTERED SHOWERS AND ISOLATED TSTMS ARE
WITHIN 90 NM EAST OF THE FRONT. A BROAD ELONGATED UPPER LEVEL
LOW CENTERED NEAR 24N69W COVERS THE REMAINDER OF THE W ATLC AND
EXTENDS INFLUENCE THROUGH THE WINDWARD PASSAGE INTO THE WESTERN
CARIBBEAN SEA. THIS UPPER LEVEL FEATURE IS PROVIDING DIFFLUENCE
ALOFT ENHANCING THE ISOLATED SHOWERS AND TSTMS ASSOCIATED WITH
SHARY. FARTHER EAST OVER THE CENTRAL AND EASTERN ATLC...A
SURFACE RIDGE CONTINUES TO DOMINATE W OF 60W WITH ONLY A WEAK
1012 MB LOW CENTERED NEAR 25N44W EMBEDDED WITHIN THE RIDGE. THIS
LOW IS LOCATED ON THE WESTERN END OF AN UPPER LEVEL TROUGH THAT
EXTENDS AN AXIS FROM THE MADEIRA ISLANDS TO 27N30W TO 27N43W.
ISOLATED SHOWERS ARE OCCURRING FROM 23N-27N BETWEEN 40W-46W.

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

$$
HUFFMAN




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