000 AXNT20 KNHC 031146 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST MON NOV 03 2008 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...SPECIAL FEATURE... IN THE W CARIBBEAN...A SURFACE TROUGH EXTENDS FROM N OF PANAMA NEAR 10N80W...TO A 1010 MB SURFACE LOW IN THE SW CARIBBEAN NEAR 12N80W...TO E CUBA NEAR 21N76W. LOW LEVEL CONVERGENCE NEAR THE TROUGH AND LOW...COMBINED WITH DEEP MOISTURE AND UPPER LEVEL DIVERGENCE OVER THE W CARIBBEAN...IS SUPPORTING ISOLATED SHOWERS AND THUNDERSTORMS S OF 18N W OF 76W. UPPER-LEVEL WINDS ARE FAVORABLE FOR SOME DEVELOPMENT OF THIS SYSTEM OVER THE NEXT COUPLE OF DAYS. ...THE ITCZ... ITCZ AXIS IS ANALYZED ALONG 7N10W 4N22W 3N35W 4N46W 5N59W. SCATTERED MODERATE CONVECTION IS WITHIN 180 NM EITHER SIDE OF THE ITCZ AXIS BETWEEN 12W-16W. ISOLATED MODERATE CONVECTION IS FROM 2N-12N BETWEEN 20W-33W...WHICH IS BEING ENHANCED BY UPPER LEVEL DIVERGENCE. SCATTERED MODERATE CONVECTION IS FROM 2N-5N BETWEEN 34W-39W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL LOW IS OVER SOUTH CAROLINA NEAR 34N82W...WITH INSTABILITY AND UPPER LEVEL MOISTURE NEAR THIS LOW RESULTING IN ISOLATED SHOWERS AND THUNDERSTORMS IN THE GULF N OF 27N E OF 85W. THIS LOW IS EMBEDDED WITHIN A BROAD UPPER LEVEL TROUGH THAT COVERS MUCH OF THE GULF. DEEP LAYER DRY AIR ROTATING CYCLONICALLY AROUND THE BASE OF THIS TROUGH IS RESULTING IN MAINLY FAIR WEATHER CONDITIONS ACROSS THE S AND W GULF. MEANWHILE...A SURFACE RIDGE OF HIGH PRESSURE IS AFFECTING MUCH OF THE W GULF. ADDITIONALLY...STRONG N TO NE SURFACE WINDS ARE BLOWING THROUGH THE ISTHMUS OF TEHUANTEPEC RESULTING IN GALE FORCE WINDS IN THE E PACIFIC REGION. THESE WINDS ARE EXPECTED TO SUBSIDE TO BELOW GALE FORCE BY 03/1800 UTC. CARIBBEAN SEA... AN UPPER LEVEL HIGH IS OVER THE E CARIBBEAN NEAR 15N70W...WITH ANTICYCLONIC FLOW AROUND THE HIGH COVERING MUCH OF THE CARIBBEAN. DEEP MOISTURE AND UPPER LEVEL DIVERGENCE W OF THE HIGH...AS WELL AS LOW LEVEL CONVERGENCE AROUND A SURFACE LOW AND SURFACE TROUGH IN THE W CARIBBEAN...ARE SUPPORTING ISOLATED SHOWERS AND THUNDERSTORMS OVER THE W CARIBBEAN. PLEASE SEE THE SPECIAL FEATURE SECTION FOR MORE INFORMATION ON THIS SYSTEM. FARTHER TO THE E...UPPER LEVEL DIVERGENCE W OF THE UPPER HIGH IS SUPPORTING ISOLATED MODERATE CONVECTION FROM 12N-18N BETWEEN 68W-73W. DEEP LAYER DRY AIR E OF THE UPPER HIGH IS RESULTING IN MAINLY FAIR WEATHER CONDITIONS ACROSS THE E CARIBBEAN. ALSO...DEEP LAYER DRY AIR IN THE BASE OF THE UPPER TROUGH OVER THE GULF OF MEXICO IS MOVING INTO THE FAR NW CARIBBEAN. ATLANTIC OCEAN... OVER THE W ATLC...STRONG SOUTHWESTERLY FLOW ALOFT IS PRESENT BETWEEN AN UPPER LOW OVER SOUTH CAROLINA NEAR 34N82W AND AN UPPER HIGH OVER THE E CARIBBEAN NEAR 15N70W. UPPER LEVEL DIVERGENCE TO THE S OF A MAXIMUM IN MID/UPPER-LEVEL WIND SPEED OVER THE W ATLC IS INDUCING DEEP ATMOSPHERIC LIFT OVER PORTIONS OF THE W ATLC. ADDITIONALLY...A SURFACE TROUGH EXTENDS FROM E CUBA NEAR 21N76W TO A 1012 MB SURFACE LOW NEAR 22N76W...WITH A WARM FRONT EXTENDING FROM THE LOW TO 25N67W TO 27N59W...AND A STATIONARY FRONT EXTENDING TO THE NE FROM 27N59W TO 29N54W TO 31N51W. FURTHER TO THE NE...THE STATIONARY FRONT IS WEAKENING. LOW LEVEL CONVERGENCE NEAR THESE SURFACE FEATURES...COMBINED WITH DEEP MOISTURE MOVING NORTHEASTWARD FROM THE W CARIBBEAN AND THE DEEP ATMOSPHERIC LIFT...IS SUPPORTING ISOLATED MODERATE CONVECTION FROM 22N-30N BETWEEN 62W-76W AND SCATTERED MODERATE CONVECTION FROM 27N-32N BETWEEN 45W-50W. OVER THE NEXT DAY...COMPUTER MODEL GUIDANCE INDICATES THAT ATMOSPHERIC LIFT OVER THESE BOUNDARIES WILL INCREASE AS THE UPPER LOW OVER SOUTH CAROLINA NEAR 34N82W APPROACHES THE W ATLC. ACCORDINGLY...THE GUIDANCE INDICATES THAT THE WARM FRONT WILL BECOME A DOMINANT FRONT AS IT MOVES NORTHWARD WITH THE SURFACE LOW...AND THAT A COLD FRONT WILL FORM SW OF THE SURFACE LOW WITH A SURFACE TROUGH PERSISTING NW OF THE SURFACE LOW. INCREASED NORTHERLY WINDS TO THE W OF THE SURFACE TROUGH AND COLD FRONT ARE EXPECTED. FARTHER TO THE E...AN UPPER LEVEL TROUGH IS PRESENT WITH AN AXIS THAT EXTENDS FROM AN UPPER LOW NEAR 32N33W TO 19N42W TO 5N50W...WITH AN ACCOMPANYING SURFACE TROUGH THAT EXTENDS FROM 19N43W TO 15N45W TO 11N49W. INCREASED CLOUDINESS COINCIDES WITH THIS SURFACE TROUGH...WITH THE INCREASED CLOUDINESS EXTENDING FROM 11N49W TO 13N55W TO 17N59W DUE TO LOW LEVEL CONVERGENCE RESULTING FROM REGIONAL VARIATIONS IN LOW LEVEL WIND SPEED. FARTHER TO THE E...A DEEP LAYER TROUGH IS N OF 24N E OF 34W...WHICH IS SUPPORTING A SURFACE COLD FRONT THAT EXTENDS FROM THE W COAST OF AFRICA NEAR 19N16W TO 20N19W AND A SURFACE TROUGH THAT EXTENDS FROM 20N19W TO 21N26W TO 28N33W. DEEP LAYER DRY AIR IS PREVENTING DEEP CONVECTION ALONG THE SURFACE COLD FRONT AND SURFACE TROUGH. OVER THE TROPICAL ATLC...AN EAST-TO-WEST UPPER RIDGE IS ALONG 13N BETWEEN THE AFRICAN COAST AND 33W. $$ COHEN