000 AXNT20 KNHC 111748 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...THE ITCZ... ITCZ IS CENTERED ALONG 5N9W 3N20W 3N40W AND INTO NE BRAZIL NEAR 1S50W. SCATTERED MODERATE CONVECTION IS FROM 1N-5N BETWEEN 19W-24W. ...DISCUSSION... GULF OF MEXICO... SOUTHWESTERLY FLOW ALOFT IN ASSOCIATION WITH A DEEP TROUGH OVER THE CENTRAL CONUS SUPPORTS A SURFACE COLD FRONT THAT AT 2100 UTC CROSS THE CENTRAL FLORIDA PANHANDLE AND ENTERS THE GULF NEAR APALACHICOLA BAY TO 25N93W TO THE E COAST OF MEXICO NEAR 19N95W AND INLAND ACROSS SRN MEXICO. LOW LEVEL CONVERGENCE IS GENERATING SCATTERED SHOWERS WITHIN 90 NM OF THE FRONT N OF 24N AND ISOLATED TSTMS WITHIN 90 NM OF THE FRONT S OF 24N IN THE WRN BAY OF CAMPECHE. INCREASED NORTHERLY WINDS...AS WELL AS COOLER AND DRIER CONDITIONS...ARE OBSERVED IN THE WAKE OF THE FRONT. AHEAD OF THE FRONT...INCLUDING THE SE GULF AND SRN FLORIDA PENINSULA...RETURN FLOW AROUND A RIDGE EXTENDING FROM THE W ATLC IS RESULTING IN SOUTHERLY WINDS OF 10 TO 15 KT. DEEP LAYER DRY AIR IS INHIBITING DEEP CONVECTION ACROSS THE SE GULF. CARIBBEAN SEA... AN UPPER RIDGE IS ACROSS THE CARIBBEAN REGION...WITH THE RIDGE AXIS EXTENDING FROM N VENEZUELA TO JAMAICA AND ACROSS CUBA. DRY AIR IN SUBSIDENCE IS ASSOCIATED WITH THIS UPPER RIDGE RESULTING IN GENERALLY FAIR WEATHER ACROSS MUCH OF THE CARIBBEAN SEA. HOWEVER...ACROSS THE W CARIBBEAN...DEEP MOISTURE W OF 80W AND MODERATE TO STRONG EASTERLY TRADE WINDS ARE USHERING IN SCATTERED SHOWERS ACROSS COASTAL CENTRAL AMERICA AND AND THE NW CARIBBEAN S OF 20N. THE STRONGEST OF THE TRADE WINDS...UP TO 30 KT...WERE OBSERVED ON AN EARLIER QUIKSCAT PASS. A COLD FRONT IS FORECAST TO MOVE ACROSS THE YUCATAN CHANNEL AND INTO THE NW CARIBBEAN TUESDAY. ATLANTIC OCEAN... A DEEP TROUGH IS PRESENT ACROSS THE CENTRAL NORTH ATLC AND SUPPORTS A SURFACE COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N42W TO 27N53W CONTINUING STATIONARY TO 25N60W AND REMAINS WEAKENING AS A SURFACE TROUGH TO 25N69W. SCATTERED SHOWERS ARE LOCATED WITHIN 60 NM ON EITHER SIDE OF THE FRONTAL BOUNDARY. TO THE W OF THESE FRONTS...DEEP LAYER DRY AIR AND SUBSIDENCE ARE RESULTING IN GENERALLY FAIR WEATHER ACROSS MUCH OF THE W ATLC. THIS SUBSIDENCE IS BEING ENHANCED BY A 1028 MB SURFACE HIGH CENTERED NEAR 33N58W. ALSO...A SURFACE COLD FRONT IS FORECAST TO MOVE OFF THE SE CONUS INTO THE W ATLC THIS EVENING. FARTHER TO THE E...AN UPPER TROUGH IS PRESENT WITH AXIS EXTENDING FROM 19N28W TO 30N40W. ATMOSPHERIC INSTABILITY ASSOCIATED WITH THIS UPPER TROUGH IS RESULTING IN SCATTERED SHOWERS FROM 17N-29N BETWEEN 21W-36W. UPPER DIFFLUENCE POSITIONED TO THE NE OF THE TROUGH AXIS IN SOUTHWESTERLY FLOW ALOFT IS ENHANCING THE SCATTERED SHOWERS. ACROSS THE TROPICAL ATLC...AN UPPER RIDGE AXIS EXTENDS FROM 7N10W TO 3N30W. UPPER LEVEL DIVERGENCE NEAR THIS UPPER RIDGE IS ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ. $$ HUFFMAN