000 AXNT20 KNHC 280925 CCA TWDAT TROPICAL WEATHER DISCUSSION...CORRECTED NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST FRI NOV 28 2008 ...CORRECTED TO INCLUDE MENTION OF SURFACE TROUGH IN TROPICAL NORTH ATLANTIC... 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 0445 UTC. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 8N12W 5N22W 6N33W 8N44W 6N58W. A SURFACE TROUGH...EXTENDING FROM 11N48W TO 9N48W TO 7N49W...IS EMBEDDED WITHIN THE ITCZ. SCATTERED MODERATE CONVECTION IS OCCURRING WITHIN 180 NM EITHER SIDE OF THIS SURFACE TROUGH N OF 10N. ELSEWHERE...SCATTERED MODERATE CONVECTION IS FROM 4N-8N BETWEEN 19W-27W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 4N-9N BETWEEN 28W-39W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL RIDGE COVERS THE GULF REGION...WITH STRONG UPPER LEVEL WINDS ACROSS THE NORTHERN PERIPHERY OF THE RIDGE OVER THE SE CONUS AND N GULF. UPPER LEVEL MOISTURE CONTINUES STREAMING ACROSS THE N GULF...WHILE DEEP LAYER DRY AIR IS PRESENT OVER THE S GULF. DEEP LAYER SUBSIDENCE AND STABLE ATMOSPHERIC CONDITIONS ARE RESULTING IN FAIR WEATHER CONDITIONS ACROSS MUCH OF THE GULF REGION. THIS DEEP LAYER SUBSIDENCE IS BEING ENHANCED ACROSS E PORTIONS OF THE GULF REGION...WHERE UPPER LEVEL CONVERGENCE IN THE NW QUADRANT OF A 120-130 KT UPPER LEVEL JET MAXIMUM ENTERING THE W ATLC IS SUPPORTING A 1021 MB SURFACE HIGH OVER THE NE GULF NEAR 28N83W. FARTHER NW...A DEEP TROUGH OVER THE GREAT BASIN OF THE W CONUS IS SUPPORTING A SURFACE FRONT THAT EXTENDS FROM THE UPPER MIDWEST TO THE SOUTHERN PLAINS AND EXTENDS ACROSS THE CENTRAL AND NORTHERN ROCKIES OF THE CONUS. AS THE DEEP TROUGH MOVES EASTWARD...THE SURFACE FRONT WILL MOVE SOUTHWARD ACROSS THE N GULF THIS WEEKEND AS A COLD FRONT...WITH SOUTHERLY FLOW INCREASING AHEAD OF THE FRONT. THE FRONT IS ALSO FORECAST BE ACCOMPANIED BY SCATTERED SHOWERS AND THUNDERSTORMS. IN THE WAKE OF THE COLD FRONT...INCREASED NORTHERLY AND NORTHWESTERLY SURFACE WINDS ARE EXPECTED...ALONG WITH RELATIVELY COOLER AND DRIER CONDITIONS. CARIBBEAN SEA... IN THE SW CARIBBEAN...A 1011 MB SURFACE LOW IS CENTERED N OF PANAMA NEAR 10N78W. LOW LEVEL CONVERGENCE NEAR THIS SURFACE LOW IS SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS S OF 11N W OF 75W...INCLUDING PANAMA AND S COSTA RICA. THIS ACTIVITY IS BEING ENHANCED BY UPPER LEVEL DIFFLUENCE IN THE VICINITY OF AN UPPER RIDGE PRESENT OVER THE W CARIBBEAN...WITH THE AXIS OF THIS UPPER RIDGE EXTENDING FROM N COLOMBIA NEAR 11N74W TO 13N83W TO SE MEXICO NEAR 18N92W INTO THE W GULF REGION. OVER THE N CARIBBEAN...DEEP LAYER SUBSIDENCE IS IN PLACE RESULTING IN FAIR WEATHER CONDITIONS...WHERE STRONG WESTERLY CONFLUENT FLOW ALOFT IS PRESENT. RELATIVELY DRY CONDITIONS PREVAIL ACROSS PORTIONS OF THE N CARIBBEAN...WITH DEWPOINTS IN THE UPPER 50S AND LOWER 60S ACROSS CUBA. THIS DRIER AIR IS A RESULT OF N TO NE SURFACE WINDS AROUND THE 1021 MB SURFACE HIGH IN THE NE GULF NEAR 28N83W ADVECTING THE STRONGLY MODIFIED CONTINENTAL POLAR AIRMASS ACROSS THE N CARIBBEAN REGION. THIS AIRMASS IS IN THE WAKE OF A COLD FRONT THAT IS E OF THE BAHAMAS. OUTSIDE OF SHOWER AND THUNDERSTORM ACTIVITY...FRESH TRADEWINDS PREVAIL ACROSS THE CARIBBEAN. ATLANTIC OCEAN... STRONG WESTERLY FLOW ALOFT COVERS MUCH OF THE W AND CENTRAL ATLC. A SURFACE RIDGE EXTENDS INTO THE W ATLC FROM A 1021 MB SURFACE HIGH OVER THE NE GULF NEAR 28N83W...WITH SUBSIDENCE AND FAIR WEATHER IN THE VICINITY OF THIS RIDGE. TO THE E OF THE BAHAMAS...A SURFACE COLD FRONT EXTENDS FROM 24N69W TO 28N62W TO 32N57W TO N OF THE DISCUSSION AREA. LOW LEVEL CONVERGENCE IS RESULTING IN SCATTERED SHOWERS WITHIN 90 NM EITHER SIDE OF THIS COLD FRONT. FARTHER TO THE E...UPPER LEVEL DIVERGENCE IN THE NE QUADRANT OF A 100-110 KT UPPER LEVEL JET MAXIMUM IS SUPPORTING A 1003 MB SURFACE LOW IN THE CENTRAL ATLC NEAR 30N42W...WITH AN ASSOCIATED SURFACE TROUGH EXTENDING FROM 31N43W TO 33N35W TO 28N31W TO 23N32W. LOW LEVEL CONVERGENCE NEAR THESE FEATURES IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS N OF 19N BETWEEN 26W-35W...WITH SCATTERED SHOWERS N OF 28N BETWEEN 37W-42W. ALSO...A NEW 1007 MB SURFACE LOW HAS FORMED NEAR 32N50W...AND AN ATTENDANT SURFACE TROUGH EXTENDS FROM THIS SURFACE LOW TO 30N49W TO 28N46W...WITH LOW LEVEL CONVERGENCE SUPPORTING SCATTERED SHOWERS N OF 29N BETWEEN 46W-50W. AN UPPER TROUGH AXIS IS TILTED FROM 27N30W TO 32N36W TO AN UPPER LOW NEAR 36N46W...WITH UPPER DIFFLUENCE E OF THE UPPER TROUGH AXIS ENHANCING THE SHOWER AND THUNDERSTORM ACTIVITY N OF 26N BETWEEN 26W-35W. ACROSS THE E ATLC...A SURFACE RIDGE IS N OF 17N E OF 28W...WHERE SUBSIDENCE IS RESULTING IN FAIR WEATHER CONDITIONS. OVER THE TROPICAL ATLC...AN UPPER RIDGE IS PRESENT S OF 10N W OF 21W...WITH ASSOCIATED UPPER LEVEL DIFFLUENCE ENHANCING THE CONVECTION IN THE VICINITY OF THE ITCZ. ADDITIONALLY...A SURFACE TROUGH IN THE TROPICAL NORTH ATLC EXTENDS FROM 16N45W TO 11N51W TO 8N59W. LOW LEVEL CONFLUENCE IN THE VICINITY OF THIS TROUGH IS RESULTING IN SCATTERED SHOWERS AND THUNDERSTORMS WITHIN 120 NM EITHER SIDE OF THIS FEATURE. ALSO...A SURFACE TROUGH...EXTENDING FROM 11N48W TO 9N48W TO 7N49W...IS EMBEDDED WITHIN THE ITCZ...WITH SCATTERED MODERATE CONVECTION OCCURRING WITHIN 180 NM EITHER SIDE OF THIS SURFACE TROUGH N OF 10N. $$ COHEN