000 AXNT20 KNHC 152342 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI MAR 15 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 07N12W TO 05N15W TO 05N19W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS 05N19W TO 05N25W TO THE EQUATOR NEAR 44W. ISOLATED MODERATE CONVECTION IS S OF 05N BETWEEN 20W-38W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES FAIRLY DRY AIR ALOFT OVER THE GULF DUE TO CONFLUENT UPPER LEVEL FLOW ALONG 28N AND MIDDLE LEVEL NORTHWESTERLY FLOW. THIS OVERALL ATMOSPHERIC REGIME ALOFT IS CONTINUING TO SUPPORT A BROAD SURFACE RIDGE ANCHORED BY A 1027 MB HIGH CENTERED IN THE NE GULF NEAR 29N84W AND A LOCALIZED 1026 MB HIGH CENTERED ACROSS EAST-CENTRAL MEXICO NEAR 22N98W. LIGHT ANTICYCLONIC SURFACE WINDS ARE FOUND GENERALLY N OF 26N E OF 91W WITH THE REMAINDER OF THE GULF UNDER EAST TO SOUTHEAST WINDS IN THE RANGE OF 10 TO 20 KT. THE RIDGE IS FORECAST TO SLIDE EASTWARD THROUGH THE WEEKEND WITH SOUTHERLY RETURN FLOW BECOMING DOMINATE AFTER EARLY SATURDAY. WINDS WILL REMAIN SOUTHERLY THROUGH LATE MONDAY AS AN AREA OF LOW PRESSURE DEVELOPS OVER THE SOUTHERN PLAINS. BY EARLY TUESDAY...THE ASSOCIATED COLD FRONT WILL BE POISED TO EMERGE OFF THE TEXAS AND LOUISIANA COAST AND INTO PORTIONS OF THE NORTHERN GULF WATERS. CARIBBEAN SEA... WEST-SOUTHWESTERLY MIDDLE TO UPPER LEVEL FLOW IS NOTED ON WATER VAPOR IMAGERY THIS EVENING OVER THE ENTIRE CARIBBEAN SEA BASIN. WHILE THIS MIDDLE TO UPPER LEVEL ATMOSPHERE IS RELATIVELY DRY AND STABLE...AT THE SURFACE...THE MAIN FEATURE IMPACTING THE BASIN THIS EVENING IS A SHEAR LINE ANALYZED ACROSS HISPANIOLA NEAR 19N72W TO EASTERN JAMAICA NEAR 18N77W TO JUST OFF THE COAST OF NICARAGUA NEAR 14N83W. WIDELY SCATTERED LOW-TOPPED SHOWERS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE SHEAR LINE. IN ADDITION...A RECENT ASCAT PASS AROUND 15/1528 UTC INDICATED STRONGER N-NE WINDS IN THE RANGE OF 20 TO 30 KT NORTHWEST OF THE BOUNDARY. THE SHEAR LINE IS EXPECTED TO BECOME DIFFUSE OVER THE NEXT 12 TO 24 HOURS AS A BROAD SURFACE RIDGE CURRENTLY OVER THE EASTERN GULF OF MEXICO BUILDS EASTWARD INTO THE SW NORTH ATLC. AS THE PRESSURE GRADIENT TIGHTENS BETWEEN 65W AND 80W BY LATE SATURDAY...AN AREA OF 20 TO 25 KT TRADE WINDS IS EXPECTED ACROSS PORTIONS OF THE CENTRAL CARIBBEAN AND WILL PERSIST THROUGH TUESDAY. OTHERWISE THIS EVENING...SKIES AND CONDITIONS REMAINS MOSTLY FAIR ACROSS THE SOUTH-CENTRAL AND EASTERN CARIBBEAN. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS FOUND ON WATER VAPOR IMAGERY NORTH OF THE DISCUSSION NEAR 44N61W WITH AXIS EXTENDING SOUTH-SOUTHWEST TO 32N67W TO A BASE NEAR 26N74W. THIS TROUGHING SUPPORTS A PAIR OF COLD FRONT ANALYZED ACROSS THE CENTRAL ATLC INTO SOUTHERN PORTIONS OF THE SW NORTH ATLC. THE PRIMARY COLD FRONT EXTENDS FROM 32N53W TO 25N60W TO NORTHERN HISPANIOLA NEAR 20N71W. WIDELY SCATTERED SHOWERS ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THE FRONT. A SECONDARY COLD FRONT FOLLOWS ANALYZED FROM 32N58W TO THE SE BAHAMAS NEAR 22N74W TO 21N76W. ISOLATED SHOWERS ARE POSSIBLE WITHIN 60 NM EITHER SIDE OF THE BOUNDARY. THESE TWO FRONTS ARE EXPECTED TO MERGE OVER THE NEXT 24 HOURS WHILE MOVING NE ACROSS THE CENTRAL ATLC. FARTHER EAST...AN MIDDLE TO UPPER LEVEL LOW IS CENTERED NEAR 36N26W AND CONTINUES TO SUPPORTS A 993 MB LOW CENTERED SOUTH OF THE AZORES NEAR 36N28W. THE ASSOCIATED COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N22W AND EXTENDS S-SW ALONG 30N22W TO 25N24W TO 18N31W. A SECONDARY WAVE OF ENERGY IS ALSO NOTED AS A SURFACE TROUGH AXIS FROM 30N24W TO 23N32W. BOTH OF THESE BOUNDARIES HAVE VERY LITTLE PRECIPITATION ASSOCIATED WITH THEM AT THIS TIME. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN