000 AXNT20 KNHC 222357 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST THU NOV 22 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 ACROSS W AFRICA TO THE COAST OF SIERRA LEONE AT 7N12W TO 6N18W. THE ITCZ CONTINUES FROM 6N18W ALONG 6N36W 8N49W. A SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ ALONG 10N51W TO 5N52W. SCATTERED STRONG CONVECTION IS FROM 4N-8N BETWEEN 21W-30W. SCATTERED MODERATE CONVECTION IS FROM 6N-9N BETWEEN 30W-46W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 5N-10N BETWEEN 46W-55W. ...DISCUSSION... GULF OF MEXICO... MAINLY ZONAL WESTERLY FLOW COVERS THE GULF OF MEXICO EXCEPT FRO MORE NW FLOW OVER THE FAR EASTERN GULF AROUND THE WEST SIDE OF AN UPPER LEVEL TROUGH IN THE WEST ATLC. WATER VAPOR IMAGERY INDICATES THAT MOSTLY DRY AIR ALOFT SPREADS ACROSS THE AREA HELPING PROVIDE FAIR CONDITIONS THROUGHOUT THE BASIN. AT THE SURFACE...RIDGING CONTINUES WITH AXIS EXTENDING FROM A HIGH CENTER OVER ALABAMA. LIGHT ANTI-CYCLONIC FLOW OF 5-10 KT IS AROUND THE RIDGE WITH SOME WINDS REACHING 15-20 KT AROUND THE PERIPHERY INCLUDING THE SE GULF AND THE SW GULF. A FEW ISOLATED SHOWERS ARE IN THE FAR SW GULF AS WELL NEAR A SURFACE TROUGH PARALLELING THE MEXICAN COAST ALONG 23N98W TO 18N94W. SURFACE RIDGING IS EXPECTED TO REMAIN ACROSS THE BASIN UNTIL A COLD FRONT REACHES THE NW GULF LATE FRIDAY OR EARLY SATURDAY. CARIBBEAN SEA... A BROAD UPPER LEVEL RIDGE COVERS THE CARIBBEAN WITH MAINLY DRY WESTERLY FLOW OVER THE NW CORNER AND THE EASTERN PORTIONS WHILE MOIST SOUTHWESTERLY FLOW COVERS THE CENTRAL CARIBBEAN. STRONG NORTHERLY FLOW OF 20-25 KT IS ACROSS THE NW CARIBBEAN. THE WINDS GET LIGHTER AND EASTERLY ACROSS THE CENTRAL AND EASTERN CARIBBEAN FORMING SURFACE CONVERGENCE NEAR A SURFACE TROUGH IN THE CENTRAL CARIBBEAN FROM HISPANIOLA NEAR 18N71W TO NORTHERN COLOMBIA AT 11N74W. THE COMBINATION OF SURFACE CONVERGENCE NEAR THE TROUGH ALONG WITH MOIST SOUTHWESTERLY FLOW ALOFT IS HELPING PRODUCE SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS SOUTH OF 15N BETWEEN 72W-81W...AS WELL AS ISOLATED SHOWERS NORTH OF 15N BETWEEN 70W-78W. THE MONSOON TROUGH SOUTH OF PANAMA AND COSTA RICA MAY ALSO BE PLAYING A ROLE IN THE ACTIVITY IN THE SW CARIBBEAN. FAIR CONDITIONS ARE ACROSS THE EASTERN CARIBBEAN. LITTLE CHANGE IS EXPECTED OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... A NARROW SHORTWAVE UPPER TROUGH EXTENDS OVER THE FAR W ATLC SUPPORTING A NEWLY DEVELOPED COLD FRONT THAT EXTENDS FROM A 1000 MB LOW NEAR 33N66W ALONG 25N69W TO 20N74W. AS OF 2100 UTC...A SURFACE TROUGH IS WEST OF THE FRONT ALONG 30N72W TO 25N76W. DRY AIR ALOFT IS INHIBITING ANY STRONG SHOWERS/THUNDERSTORMS...BUT A FEW ISOLATED SHOWERS/THUNDERSTORMS EXIST NORTH OF 30N BETWEEN 66W-76W. POSSIBLE ISOLATED SHOWERS ARE EAST OF THE FRONT FROM 18N-28N BETWEEN 60W-70W WHERE MOIST SOUTHWESTERLY FLOW ALOFT IS STREAMING FROM THE CENTRAL CARIBBEAN INTO THE ATLC. A BROAD UPPER RIDGE COVERS THE CENTRAL ATLC EXTENDING FROM THE EASTERN CARIBBEAN. THE UPPER RIDGE SUPPORTS A SURFACE RIDGE ANCHORED BY A 1015 MB HIGH NEAR 22N46W. THE RIDGE IS PROVIDING MOSTLY FAIR CONDITIONS ACROSS THE CENTRAL AND EASTERN ATLC. A FEW SHOWERS/THUNDERSTORMS ARE EAST OF THE HIGH CENTER FROM 20N-24N BETWEEN 40W-43W. AN UPPER LEVEL TROUGH IS EAST OF THE UPPER RIDGE EXTENDING ALONG 32N30W TO 14N37W TO 6N52W. THE UPPER TROUGH SUPPORTS A COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N30W TO 26N38W. ISOLATED SHOWERS ARE WITHIN 250 NM SE OF THE FRONT AXIS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON