000 AXNT20 KNHC 111106 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST SUN JAN 11 2009 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 1045 UTC. ...THE ITCZ... ITCZ IS CENTERED ALONG 5N9W 3N21W 2N32W 2N41W AND INTO NE BRAZIL NEAR 1S53W. SCATTERED MODERATE CONVECTION IS FROM 1N-3N BETWEEN 15W-21W. SCATTERED MODERATE CONVECTION IS ALSO FROM 3N-5N BETWEEN 28W-34W. ...DISCUSSION... GULF OF MEXICO... SOUTHWESTERLY FLOW ALOFT CONTINUES TO INCREASE ACROSS THE GULF REGION AS A DEEP TROUGH OVER THE CENTRAL CONUS MOVES EASTWARD. A SURFACE COLD FRONT ASSOCIATED WITH THIS DEEP TROUGH EXTENDS FROM THE W FLORIDA PANHANDLE NEAR 30N87W TO 26N94W TO THE E COAST OF MEXICO NEAR 21N97W AND EXTENDS NORTHWESTWARD ACROSS MEXICO. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ALONG AND WITHIN 90 NM AHEAD OF THE COLD FRONT. THIS ACTIVITY IS BEING ENHANCED IN THE SW QUADRANT OF AN UPPER LEVEL JET MAXIMUM LOCATED OVER THE E CONUS. THE COLD FRONT IS FORECAST TO CONTINUE MOVING SOUTHWARD ACROSS THE GULF AND REACH THE YUCATAN PENINSULA MONDAY AFTERNOON. INCREASED NORTHERLY WINDS...AS WELL AS COOLER AND DRIER CONDITIONS...ARE PRESENT IN THE WAKE OF THE FRONT. GALE CONDITIONS ARE FORECAST ACROSS PORTIONS OF THE SW GULF FOR THIS AFTERNOON AND TONIGHT. AHEAD OF THE FRONT...INCLUDING MUCH OF THE SE GULF...THE RETURN FLOW AROUND A 1027 MB SURFACE HIGH OVER THE W ATLC NEAR 33N63W IS RESULTING IN SOUTHERLY WINDS OF 10 TO 15 KT. DEEP LAYER DRY AIR IS INHIBITING DEEP CONVECTION ACROSS THE SE GULF. ADDITIONALLY...STRONG N TO NE SURFACE WINDS ARE FORECAST TO BLOW THROUGH THE ISTHMUS OF TEHUANTEPEC RESULTING IN GALE FORCE WINDS IN THE E PACIFIC REGION BEGINNING AT 12/0000 UTC. CARIBBEAN SEA... AN UPPER RIDGE IS PRESENT ACROSS THE CARIBBEAN REGION...WITH THE UPPER RIDGE AXIS EXTENDING FROM N VENEZUELA NEAR 10N65W TO 17N77W TO 21N84W. SUBSIDENCE AND STABLE ATMOSPHERIC CONDITIONS ASSOCIATED WITH THIS UPPER RIDGE ARE RESULTING IN GENERALLY FAIR WEATHER ACROSS MUCH OF THE CARIBBEAN SEA. HOWEVER...ACROSS THE W CARIBBEAN...DEEP MOISTURE IS BEING TRANSPORTED NORTHWARD TO THE W OF THE UPPER RIDGE AXIS...WHICH IS RESULTING IN ISOLATED SHOWERS S OF 18N W OF 81W. MODERATE TO STRONG EASTERLY TRADE WINDS ARE PRESENT ACROSS MUCH OF THE CARIBBEAN SEA. THESE TRADE WINDS ARE FORECAST TO CONTINUE THROUGH TUESDAY AS THE 1027 MB SURFACE HIGH IN THE W ATLC NEAR 33N63W MOVES EAST-NORTHEASTWARD. THE STRONGEST WINDS...UP TO 30 KT...ARE NEAR THE COAST OF COLOMBIA. A COLD FRONT IS FORECAST TO MOVE ACROSS THE YUCATAN CHANNEL AND INTO THE NW CARIBBEAN WEDNESDAY AND THURSDAY. ATLANTIC OCEAN... A DEEP TROUGH IS PRESENT ACROSS THE W ATLC N OF THE DISCUSSION AREA. THIS DEEP TROUGH IS ASSOCIATED WITH A SURFACE COLD FRONT THAT EXTENDS FROM NE OF THE DISCUSSION AREA TO 32N44W TO 27N51W TO 24N59W AND A DISSIPATING SURFACE STATIONARY FRONT THAT EXTENDS FROM 24N59W TO 24N64W TO 23N68W. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THE SURFACE COLD FRONT AND ISOLATED SHOWERS WITHIN 30 NM EITHER SIDE OF THE DISSIPATING SURFACE STATIONARY FRONT. TO THE W OF THESE FRONTS...DEEP LAYER DRY AIR AND SUBSIDENCE ARE RESULTING IN GENERALLY FAIR WEATHER ACROSS MUCH OF THE SW ATLC. THIS SUBSIDENCE IS BEING ENHANCED AROUND THE 1027 MB SURFACE HIGH NEAR 33N63W. ALSO...A SURFACE COLD FRONT IS FORECAST TO MOVE OFF THE SE CONUS INTO THE SW ATLC TONIGHT...WHICH WILL MERGE WITH A REINFORCING SURFACE COLD FRONT ON TUESDAY THAT IS ALSO FORECAST TO MOVE OFF THE SE CONUS INTO THE SW ATLC. GALE CONDITIONS ARE EXPECTED N OF 29N WITHIN 480 NM E OF THE COLD FRONT FOR TUESDAY AND WEDNESDAY. FARTHER TO THE E...AN UPPER TROUGH IS PRESENT WITH AN AXIS EXTENDING FROM 15N34W TO 26N39W TO 31N40W. ATMOSPHERIC INSTABILITY ASSOCIATED WITH THIS UPPER TROUGH IS RESULTING IN SCATTERED SHOWERS FROM 18N-29N BETWEEN 23W-35W. THIS ACTIVITY IS BEING ENHANCED BY ATMOSPHERIC LIFT ASSOCIATED WITH DIFFLUENCE IN SOUTHWESTERLY FLOW ALOFT TO THE E OF THIS UPPER TROUGH AXIS. FARTHER TO THE E...SUBSIDENCE IS RESULTING IN GENERALLY FAIR WEATHER IN THE VICINITY OF A 1025 MB SURFACE HIGH CENTERED NEAR 29N38W AND A 1026 MB SURFACE HIGH CENTERED NEAR 33N22W. ACROSS THE TROPICAL ATLC...AN UPPER RIDGE AXIS EXTENDS FROM 7N10W TO 5N23W TO 3N35W. UPPER LEVEL DIVERGENCE NEAR THIS UPPER RIDGE IS ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ. $$ COHEN