000 AXNT20 KNHC 112348 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST SAT JAN 11 2014 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. ...SPECIAL FEATURES... A STRONG PRESSURE GRADIENT EXISTS BETWEEN AN AREA OF LOWER PRESSURE OVER NORTHERN SOUTH AMERICA AND A STRONG SURFACE RIDGE ANCHORED TO THE NORTH-NORTHEAST ACROSS THE SW NORTH ATLC BY A 1031 MB HIGH CENTERED NEAR 35N59W. PERSISTENT TRADES IN THE RANGE OF 25 TO 35 KT ARE EXPECTED THROUGH LATE SUNDAY. SEE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/ FZNT02 KNHC FOR MORE DETAILS. AN AREA OF LOW PRESSURE IS FORECAST TO FORM IN THE VICINITY OF 21N38W SOUTH OF AN EASTERN ATLC SUBTROPICAL RIDGE. AS THE LOW FORMS AND MOVES NORTHWARD...A STRONG PRESSURE GRADIENT IS EXPECTED TO RESULT GENERATING GALE FORCE WINDS IN THE NORTHERN SEMICIRCLE BY 13/0000 UTC. SEE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 07N12W TO 04N18W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 04N18W TO 03N23W TO 04N34W TO 01N42W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 01N-06N BETWEEN 09W-37W. ...DISCUSSION... GULF OF MEXICO... A RELATIVELY SHARP MIDDLE TO UPPER LEVEL TROUGH IS PROGRESSING OVER THE EASTERN CONUS WITH AXIS ALONG 89W THAT DIPS SOUTHWARD TO A BASE OVER THE LOWER MISSISSIPPI RIVER VALLEY IN THE VICINITY OF 31N90W. THIS TROUGHING SUPPORTS A COLD FRONT ANALYZED INTO THE GULF NEAR 30N92W AND EXTENDS W-SW TO THE TEXAS GULF COAST NEAR 28N97W. WHILE THE FRONT REMAINS QUIET WITH REGARDS TO CONVECTION THIS EVENING...A PRE-FRONTAL TROUGH...WITH PORTIONS OF EMBEDDED SQUALLS...EXTENDS FROM NORTHERN FLORIDA NEAR 30N83W SW TO 27N86W TO 24N93W. MOSAIC DOPPLER RADAR AND LIGHTNING DATA INDICATE NUMEROUS SHOWERS AND SCATTERED TSTMS OCCURRING WITHIN 60 NM EITHER SIDE OF THE SQUALL LINE/SURFACE TROUGH AXIS N OF 27N. THE COLD FRONT IS EXPECTED TO MOVE EAST OF THE GULF BASIN BY EARLY SUNDAY AS A SURFACE RIDGE MOVES FROM CENTRAL TEXAS EASTWARD TO THE GULF COASTAL PLAINS. GENERALLY 10 TO 15 KT ANTICYCLONIC WINDS ARE EXPECTED SUNDAY ON THE SOUTHERN PERIPHERY OF THE RIDGING. AS THIS RIDGE SLIDES EASTWARD INTO THE SW NORTH ATLC MONDAY...THE NEXT COLD FRONT IS FORECAST TO EMERGE OFF THE TEXAS AND LOUISIANA COAST BY MID-DAY MONDAY. CARIBBEAN SEA... MUCH OF THE CARIBBEAN REMAINS FAIRLY TRANQUIL THIS EVENING WITH THE EXCEPTION OF GALE FORCE WINDS OCCURRING OFF THE COAST OF COLOMBIA. WATER VAPOR IMAGERY INDICATES VERY DRY AND STABLE AIR ALOFT DUE TO UPPER TO MIDDLE LEVEL RIDGING ANCHORED BY A MID- LEVEL ANTICYCLONE CENTERED OVER THE WINDWARD PASSAGE NEAR 20N74W. A FEW PASSING ISOLATED LOW-TOPPED SHOWERS ARE NOTED ON SATELLITE IMAGERY...BUT THE MAIN IMPACT REMAINS TO BE STRONG TRADES DUE TO A STRONG PRESSURE GRADIENT BETWEEN LOWER PRESSURE ACROSS NORTHERN SOUTH AMERICA AND A SURFACE RIDGE ANCHORED ACROSS THE SW NORTH ATLC. TRADES ARE EXPECTED TO REMAIN IN THE RANGE OF 20 TO 30 GENERALLY BETWEEN 68W-82W THROUGH THE OVERNIGHT PERIOD INTO SUNDAY. ...HISPANIOLA... CURRENTLY ONLY A FEW ISOLATED LOW-TOPPED SHOWERS ARE MOVING ACROSS THE ISLAND THIS EVENING BENEATH AN OTHERWISE FAIR AND STABLE ENVIRONMENT ALOFT DUE TO A THE PRESENCE OF A BROAD UPPER LEVEL RIDGE IN THE REGION. EXPECT THE OVERALL TRANQUIL CONDITIONS TO PERSIST OVER THE NEXT SEVERAL DAYS. ATLANTIC OCEAN... MOSTLY SOUTHWESTERLY MIDDLE TO UPPER LEVEL FLOW IS NOTED ON WATER VAPOR IMAGERY OVER THE SW NORTH ATLC THIS EVENING BETWEEN AN APPROACHING UPPER LEVEL TROUGH OVER THE EASTERN CONUS AND AN UPPER LEVEL RIDGE WITH AXIS EXTENDING FROM OVER THE WINDWARD PASSAGE REGION NEAR 20N74W N-NE TO BEYOND 35N64W. UPPER LEVEL DIFFLUENCE EAST OF THE UPPER LEVEL TROUGHING ALONG WITH LOW- LEVEL MOISTURE CONVERGENCE IN ADVANCE OF THE ASSOCIATED COLD FRONTAL BOUNDARY IS GENERATING SCATTERED SHOWERS AND TSTMS WEST OF A LINE FROM 29N81W TO 32N77W. OTHERWISE...THE REMAINDER OF THE SW NORTH ATLC IS UNDER MOSTLY FAIR SKIES AND CONDITIONS THIS EVENING DUE TO A CENTRAL ATLC RIDGE ANCHORED BY A 1031 MB HIGH CENTERED NEAR 35N59W. THIS RIDGING COVERS MUCH OF THE CENTRAL ATLC PORTION OF THE BASIN...HOWEVER ACROSS THE EASTERN ATLC...A COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N24W EXTENDING SW TO 24N45W. ISOLATED SHOWERS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE FRONT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN