000 AXNT20 KNHC 110515 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0445 UTC. ...THE ITCZ... ITCZ IS CENTERED ALONG 7N10W 3N20W 2N31W 1N42W AND INTO NE BRAZIL NEAR 1S52W. SCATTERED MODERATE CONVECTION IS FROM 4N-6N BETWEEN 21W-25W. SCATTERED MODERATE CONVECTION IS ALSO FROM 3N-7N 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 S LOUISIANA NEAR 30N91W TO 27N95W TO 25N98W. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THE COLD FRONT. THIS ACTIVITY IS BEING ENHANCED IN THE SW QUADRANT OF AN UPPER LEVEL JET MAXIMUM OVER THE E CONUS. THE COLD FRONT IS FORECAST TO MOVE SOUTHWARD ACROSS THE GULF FOR THE REMAINDER OF THIS WEEKEND INTO EARLY NEXT WEEK AND IS FORECAST TO REACH THE YUCATAN CHANNEL TUESDAY AFTERNOON. INCREASED NORTHERLY WINDS...AS WELL AS COOLER AND DRIER CONDITIONS...ARE PRESENT IN THE WAKE OF THE FRONT. GALE CONDITIONS ARE EXPECTED ACROSS PORTIONS OF THE SW GULF FOR SUNDAY THROUGH MONDAY. AHEAD OF THE FRONT...INCLUDING MUCH OF THE SE GULF...THE RETURN FLOW AROUND A 1027 MB SURFACE HIGH OVER THE W ATLC NEAR 33N67W IS RESULTING IN SOUTHERLY WINDS OF 10 TO 20 KT. DEEP LAYER DRY AIR IS INHIBITING DEEP CONVECTION ACROSS THE SE GULF. CARIBBEAN SEA... AN UPPER RIDGE IS PRESENT ACROSS THE CARIBBEAN REGION...WITH THE UPPER RIDGE AXIS EXTENDING FROM N VENEZUELA NEAR 9N65W TO 15N73W TO 20N82W. 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 SCATTERED SHOWERS FROM 14N-18N BETWEEN 79W-85W. FRESH TO STRONG TRADE WINDS ARE PRESENT ACROSS THE CARIBBEAN SEA. THESE TRADE WINDS ARE FORECAST TO CONTINUE DURING THE NEXT FEW DAYS AS THE 1027 MB SURFACE HIGH IN THE W ATLC NEAR 33N67W MOVES EAST-NORTHEASTWARD. THE STRONGEST WINDS...UP TO 30 KT...ARE NEAR THE COAST OF COLOMBIA. THE COLD FRONT CURRENTLY IN THE GULF OF MEXICO IS FORECAST TO REACH THE YUCATAN CHANNEL TUESDAY AFTERNOON. ATLANTIC OCEAN... A DEEP TROUGH IS PRESENT ACROSS THE W ATLC N OF THE DISCUSSION AREA. THIS DEEP TROUGH IS ASSOCIATED WITH A SURFACE STATIONARY FRONT THAT EXTENDS FROM 23N66W TO 27N53W TO 31N56W AND A SURFACE COLD FRONT THAT EXTENDS FROM 31N58W TO 32N44W TO NE OF THE DISCUSSION AREA. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 90 NM EITHER SIDE OF THE SURFACE STATIONARY FRONT AND SURFACE COLD 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 33N67W. FARTHER TO THE E...AN UPPER TROUGH IS PRESENT WITH AN AXIS EXTENDING FROM 15N35W TO 27N40W TO 32N41W. ATMOSPHERIC INSTABILITY ASSOCIATED WITH THIS UPPER TROUGH IS RESULTING IN SCATTERED SHOWERS FROM 16N-27N BETWEEN 25W-36W. THIS ACTIVITY IS BEING ENHANCED BY ATMOSPHERIC LIFT ASSOCIATED WITH DIFFLUENCE IN SOUTHWESTERLY FLOW ALOFT TO THE E OF THIS UPPER TROUGH AXIS. TO THE E... SUBSIDENCE IS RESULTING IN GENERALLY FAIR WEATHER IN THE VICINITY OF A 1027 MB SURFACE HIGH CENTERED NEAR 33N28W. ACROSS THE TROPICAL ATLC...AN UPPER RIDGE AXIS EXTENDS FROM 8N12W TO 6N21W TO 3N34W. UPPER LEVEL DIVERGENCE NEAR THIS UPPER RIDGE IS ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ. $$ COHEN