000 AXNT20 KNHC 191046 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT FRI APR 19 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N15W TO 04N23W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 04N23W TO THE EQUATOR NEAR 41W. SCATTERED MODERATE CONVECTION IS FROM 03N-06N BETWEEN 06W-11W. WIDELY SCATTERED MODERATE CONVECTION IS WITHIN 75 NM EITHER SIDE OF A LINE FROM 04N22W TO 05N44W. ...DISCUSSION... GULF OF MEXICO... A VIGOROUS MIDDLE TO UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY OVER THE UPPER MISSISSIPPI RIVER VALLEY THAT EXTENDS SOUTH-SOUTHWEST TO OVER THE CENTRAL PLAINS THAT SUPPORTS A COLD FRONT ANALYZED INTO THE NW GULF NEAR 29N91W SW TO THE NE MEXICO COAST NEAR 24N98W. MOSAIC DOPPLER RADAR AND LIGHTNING DATA INDICATES SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING WITHIN 60 NM EITHER SIDE OF THE FRONT. EAST OF THE FRONT...SOUTH- SOUTHEASTERLY WINDS IN THE RANGE OF 10 TO 20 KT ARE FOUND ON THE SOUTHWESTERN PERIPHERY OF A SURFACE RIDGE ANCHORED OVER THE WESTERN NORTH ATLC. SKIES REMAIN GENERALLY CLEAR THIS MORNING AS WELL SE OF A LINE FROM THE FLORIDA PANHANDLE NEAR 31N85W TO 19N96W. NW OF THE COLD FRONT...STRONG NORTHERLY WINDS...REACHING GALE FORCE...ARE OCCURRING AND FORECAST TO SPREAD SOUTH AND EAST THROUGH SATURDAY AS HIGH PRESSURE BUILDS IN FROM THE SOUTHERN PLAINS TO ACROSS THE GULF COAST. CARIBBEAN SEA... CONDITIONS REMAIN TRANQUIL OVERALL THIS MORNING ACROSS MUCH OF THE CARIBBEAN BASIN AS MODERATE DRY AIR AND SUBSIDENCE IS NOTED ON WATER VAPOR IMAGERY. CONVECTIVE DEBRIS CLOUDINESS CONTINUES TO STREAM NE ORIGINATING FROM OVER THE SOUTH AMERICAN CONTINENT. ELSEWHERE...SKIES REMAIN CLEAR WITH ONLY A FEW ISOLATED SHOWERS NOTED ON SATELLITE IMAGERY OCCURRING ACROSS THE LESSER ANTILLES AND PORTIONS OF THE NE CARIBBEAN NORTHEAST OF A LINE FROM GRENADA TO JAMAICA NEAR 18N77W. TRADES PERSIST AND WILL REMAIN QUITE BRISK THROUGH EARLY SATURDAY GENERALLY IN THE RANGE OF 15 TO 25 KT AS A RIDGE AND ASSOCIATED STRONG PRESSURE GRADIENT IS ANCHORED OVER THE SW NORTH ATLC. THIS OVERALL SYNOPTIC PATTERN IS EXPECTED TO PERSIST THROUGH THE WEEKEND WITH THE RIDGE TO THE NORTH WEAKENING GRADUALLY AND TRADES RELAXING BY EARLY SUNDAY AS A RESULT. ATLANTIC OCEAN... A DOME OF DRY AND SUBSIDENT MIDDLE TO UPPER LEVEL AIR IS NOTED ON WATER VAPOR IMAGERY OVER THE SW NORTH ATLC THAT IS PROVIDING FOR OVERALL CLEAR SKIES AND FAIR CONDITIONS THIS MORNING. LATEST SURFACE ANALYSIS SHOWS A RIDGE REMAINS ANCHORED OVER THE WESTERN NORTH ATLC BY A 1032 MB HIGH CENTERED SE OF NOVA SCOTIA NEAR 42N55W. THE ONLY FEATURE TO HIGHLIGHT IS A WEAK SURFACE TROUGH EMBEDDED WITHIN THE SOUTHERN PERIPHERY OF THE RIDGE ANALYZED FROM 25N57W TO 29N58W. POSSIBLE ISOLATED SHOWERS ARE NOTED IN THE VICINITY OF THE TROUGH AXIS FROM 24N-31N BETWEEN 54W-62W. FARTHER EAST...A MIDDLE TO UPPER LEVEL TROUGH AXIS EXTENDS FROM 35N43W TO 18N56W AND SUPPORTS A WEAK 1016 MB LOW CENTERED NEAR 37N38W AND AN ASSOCIATED COLD FRONT FROM 37N36W TO 32N37W TO 28N40W. ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 180 NM EAST OF THE COLD FRONT AS THE LOW CONTINUES TO MOVE NE AND WELL NORTH OF THE DISCUSSION AREA IN THE NEXT 12 TO 24 HOURS. THE REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF WEAK SURFACE RIDGING WITH NORTH-NORTHEASTERLY TRADES S OF 30N IN THE RANGE OF 10 TO 20 KT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN