000 AXNT20 KNHC 121749 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST TUE FEB 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 08N13W TO 04N20W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 04N20W TO 02N37W TO THE EQUATOR NEAR 46W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 02N-04N BETWEEN 27W-45W...AND FROM THE EQUATOR TO 06N BETWEEN 47W-52W. ...DISCUSSION... GULF OF MEXICO... MIDDLE TO UPPER LEVEL TROUGHING IS ASSOCIATED WITH AN UPPER LEVEL CYCLONIC CIRCULATION CENTERED OVER EASTERN QUEBEC THAT SUPPORTS A STATIONARY FRONT ANALYZED ACROSS NORTHERN FLORIDA AND ALONG THE NORTHERN GULF COAST FROM 30N85W TO 29N93W TO THE TEXAS COAST NEAR BROWNSVILLE AND THEN INLAND ACROSS NORTHEASTERN MEXICO. MOSAIC DOPPLER RADAR IMAGERY INDICATES ISOLATED SHOWERS ARE OCCURRING WITHIN 50 NM EITHER SIDE OF THE FRONT AND WELL NORTH OF THE FRONT OVER INLAND PORTIONS OF THE LOWER MISSISSIPPI RIVER VALLEY. SOUTH OF THE FRONT...THE WESTERN PERIPHERY OF A SURFACE RIDGE ANCHORED OVER THE SW NORTH ATLC IS PROVIDING FOR SOUTHERLY WINDS IN THE RANGE OF 10 TO 20 KT. SKIES REMAIN GENERALLY CLEAR OVER THE REMAINDER OF THE BASIN WITH CLOUDINESS INCREASING IN THE VICINITY OF THE FRONT N OF 26N. THE FRONT IS FORECAST TO LIFT NORTHWARD AS A WARM FRONT LATER TODAY AS SURFACE LOW PRESSURE DEVELOPS OVER EASTERN TEXAS AND MOVES EASTWARD ACROSS THE SE CONUS INTO WEDNESDAY. WITH CYCLOGENESIS ANTICIPATED...THE ASSOCIATED COLD FRONT IS EXPECTED TO EMERGE OFF THE TEXAS AND LOUISIANA COAST LATE TUESDAY INTO EARLY WEDNESDAY INTRODUCING NORTHERLY WINDS IN WAKE OF THE FRONT FOR THE NW AND WEST-CENTRAL PORTIONS OF THE GULF. CARIBBEAN SEA... NORTH-NORTHWESTERLY UPPER LEVEL FLOW DOMINATES OVER THE CARIBBEAN WITH WATER VAPOR IMAGERY INDICATING VERY DRY AIR AND STRONG SUBSIDENCE KEEPING SKIES FAIR AND CONDITIONS TRANQUIL ACROSS A MAJORITY OF THE BASIN THIS AFTERNOON. THE EXCEPTION TO AN OVERALL QUIET DAY IS THE PRESENCE OF A SHEAR LINE ANALYZED FROM THE CENTRAL ATLC INTO THE CARIBBEAN NEAR 16N62W TO 16N66W TO 16N71W. THE SHEAR LINE IS PROVIDING FOCUS FOR WIDELY SCATTERED SHOWERS FROM 14N-18N BETWEEN 58W-75W....INCLUDING A PORTION OF THE LEEWARD ISLANDS. LOW-LEVEL MOISTURE AND ISOLATED SHOWERS STRETCH WESTWARD OCCURRING OVER JAMAICA AS WELL FROM 17N-20N BETWEEN 75W-79W. OTHERWISE...TRADES REMAIN BRISK GENERALLY IN THE RANGE OF 15 TO 25 KT WITH HIGHER SPEEDS FORECAST IN CLOSE PROXIMITY TO THE COAST OF COLOMBIA. LOOKING AHEAD...THE SHEAR LINE IS EXPECTED TO CONTINUE SLOWLY DRIFTING SOUTHWARD AND BECOME DIFFUSE OVER THE NEXT 12 TO 24 HOURS WHILE CONTINUING TO PROVIDE INCREASED PROBABILITY OF PRECIPITATION ACROSS THE EASTERN CARIBBEAN. ATLANTIC OCEAN... MIDDLE TO UPPER LEVEL RIDGING EXTENDS FROM OVER CENTRAL AMERICA NEAR 15N90W NORTHEASTWARD TO BEYOND 32N72W IN THE SW NORTH ATLC. THE RIDGING IS PROVIDING SUPPORT FOR A 1026 MB SURFACE HIGH CENTERED NEAR 31N56W. FAIR SKIES AND CONDITIONS ARE NOTED N OF 20N W OF 50W IN ASSOCIATION WITH THE HIGH. HOWEVER...THE NORTHWESTERN PORTION OF THE SW NORTH ATLC IS UNDER THE INFLUENCE OF A STATIONARY FRONT ANALYZED FROM 32N76W TO THE GEORGIA COAST NEAR 31N81W. WHILE MOST OF THE CONVECTION IS LOCATED NORTH OF THE DISCUSSION AREA...ISOLATED SHOWERS ARE OCCURRING N OF 31N BETWEEN 68W-80W. FARTHER EAST...AN MIDDLE TO UPPER LEVEL TROUGH WITH AXIS ALONG 42W DIPS SOUTHWARD INTO THE CENTRAL ATLC AND SUPPORTS A COLD FRONT ANALYZED FROM 32N39W TO 23N47W WHICH THEN BECOMES A SHEAR LINE TO 17N60W AND INTO THE EASTERN CARIBBEAN SEA. WIDELY SCATTERED SHOWERS ARE OCCURRING WITHIN 150 NM EITHER SIDE OF THE COLD FRONT AND WITHIN 120 NM EITHER SIDE OF THE SHEAR LINE. OTHERWISE THE REMAINDER OF THE EASTERN ATLC IS DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1032 MB HIGH CENTERED EAST OF THE AZORES NEAR 38N20W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN