000 AXNT20 KNHC 122345 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST SAT JAN 12 2013 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 INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N11W TO 03N20W TO 03N44W TO THE EQUATOR NEAR 50W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 02N-07N BETWEEN 27W-45W. ...DISCUSSION... GULF OF MEXICO... A 1023 MB HIGH IS CENTERED OVER THE SW NORTH ATLC NEAR 30N74W THAT EXTENDS A RIDGE AXIS W-SW ACROSS THE FLORIDA PENINSULA AND INTO THE EASTERN GULF PRODUCING A WARM AND MOSTLY DRY WEATHER PATTERN WITH MAINLY MODERATE TO FRESH S TO SE WINDS. DOPPLER RADAR IMAGERY SHOWS ISOLATED SHOWERS ACROSS FLORIDA STRAITS AND SE GULF FROM 24N TO 26N BETWEEN 81W AND 84W. THE HIGH IS FORECAST TO SLIDE WESTWARD SLIGHTLY OVERNIGHT REMAINING NEARLY STATIONARY OVER THE SW NORTH ATLC THROUGH EARLY SUNDAY. IN THE MEANTIME...SOUTHERLY RETURN FLOW IS EXPECTED TO CONTINUE ACROSS THE WESTERN GULF AHEAD OF THE NEXT COLD FRONT FORECAST TO EMERGE OFF THE TEXAS AND LOUISIANA COAST LATE SUNDAY MORNING INTO THE AFTERNOON. IN WAKE OF THE FRONT...FRESH TO STRONG NORTHERLY WINDS ARE EXPECTED WITH SCATTERED SHOWERS AND ISOLATED TSTMS ALONG AND IN VICINITY OF THE FRONT. IN THE UPPER LEVELS...A RIDGE EXTENDS FROM OVER THE SW GULF NE TO BEYOND THE MID-ATLC COAST. AN UPPER LEVEL TROUGH AXIS EXTENDS FROM AN UPPER LEVEL LOW CENTERED IN THE SW NORTH ATLC NEAR 29N79W TO OVER WESTERN CUBA NEAR 22N84W. MULTILAYERED CLOUDINESS IS NOTED OVER MUCH OF THE GULF N OF 20N W OF 84W WHILE THE REMAINDER OF THE BASIN IS UNDER MODERATE TO STRONG UPPER LEVEL SUBSIDENCE AND DRY AIR. CARIBBEAN SEA... HIGH PRESSURE NORTH OF THE AREA IS PRODUCING FRESH TO STRONG TRADE WINDS ACROSS THE SOUTH-CENTRAL CARIBBEAN WITH THE STRONGEST WINDS OCCURRING NEAR THE COAST OF COLOMBIA. EARLIER MORNING SCATTEROMETER DATA INDICATED 20 TO 30 KT E-NE WINDS ACROSS THIS AREA. MODERATE TO FRESH WINDS ARE BLOWING ACROSS THE REMINDER OF THE BASIN AND ARE EXPECTED TO PERSIST THROUGH THE OVERNIGHT HOURS. HOWEVER...WINDS ARE FORECAST TO DIMINISH SLIGHTLY...IN THE RANGE OF 20 TO 25 KT...AS THE HIGH PRESSURE TO THE NORTH WEAKENS ON SUNDAY AND THE PRESSURE GRADIENT RELAXES. SHALLOW MOISTURE EMBEDDED IN THE TRADE WIND FLOW WILL PROGRESS WESTWARD ACROSS THE BASIN PRODUCING ISOLATED TO SCATTERED SHOWERS. LOW-LEVEL CONVERGENCE IS ALSO GENERATING SOME SHOWER ACTIVITY OVER PARTS OF NICARAGUA...HONDURAS...AND THE GULF OF HONDURAS FROM 12N-18N BETWEEN 83W-89W. FINALLY...REMNANTS OF A FRONTAL BOUNDARY...NOW ANALYZED AS A SHEAR LINE EXTENDS GENERALLY ALONG 20N BETWEEN 50W-73W. WIDELY SCATTERED SHOWERS ARE OCCURRING MOSTLY SOUTH OF THE SHEAR LINE AXIS IMPACTING THE NE CARIBBEAN WATERS N OF 17N E OF 73W...INCLUDING HISPANIOLA... PUERTO RICO...AND PORTIONS OF THE LEEWARD ISLANDS. ALOFT...WATER VAPOR IMAGERY INDICATES A MAJORITY OF THE BASIN IS UNDER STRONG SUBSIDENCE AND AIR DRY LIMITING ANY SIGNIFICANT DEEP CONVECTION. ATLANTIC OCEAN... A 1023 MB HIGH PRESSURE IS CENTERED IN THE SW NORTH ATLC WATERS NEAR 30N74W AND PROVIDES INFLUENCE N OF 20N W OF 55W. IT CONTINUES TO PROVIDE MOSTLY FAIR WEATHER. FARTHER EAST...A COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N33W THEN CONTINUES S-SW TO 20N49W WHERE IT TRANSITIONS TO THE SHEAR LINE ALONG 19N55W TO 20N71W. ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 90 NM EAST OF THE COLD FRONT N OF 28N WHILE ISOLATED SHOWERS ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THE REMAINDER OF THE BOUNDARY S OF 28N. THE EASTERN ATLC IS UNDER THE INFLUENCE OF A RIDGE ANCHORED BY A 1025 MB HIGH CENTERED NE OF THE MADEIRA ISLANDS NEAR 35N14W. ALOFT...A RIDGE/TROUGH/RIDGE PATTERN DOMINATES THE DISCUSSION AREA. A VERY LARGE UPPER LEVEL LOW IS SPINNING OVER THE CENTRAL ATLANTIC NEAR 37N46W SUPPORTING THE CENTRAL ATLANTIC COLD FRONT. A SMALL UPPER LEVEL LOW IS JUST OFF OF NE FLORIDA NEAR 29N79W WITH A TROUGH AXIS EXTENDING SW OVER THE SOUTHERN FLORIDA PENINSULA AND INTO THE NW CARIBBEAN SEA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN