000 AXNT20 KNHC 092351 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED APR 09 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 COLD FRONT EXTENDS ACROSS THE SW NORTH ATLC FROM 32N68W SW TO 25N73W TO EASTERN CUBA NEAR 21N77W PROVIDING GALE FORCE SOUTH- SOUTHWESTERLY WINDS N OF 28M WITHIN 240 NM EAST OF THE FRONT. WHILE THE UPPER LEVEL DYNAMICS SUPPORTING THE LOW MOVES NORTH OF THE SW NORTH ATLC REGION THROUGH THE OVERNIGHT HOURS...WINDS ARE FORECAST TO DECREASE BELOW GALE FORCE BY EARLY THURSDAY. SEE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/ FZNT02 KNHC FOR MORE DETAILS. A STRONG PRESSURE GRADIENT IS FORECAST TO GENERATE GALE FORCE NE TO E WINDS BEGINNING 11/0000 UTC ACROSS THE SW CARIBBEAN SEA FROM 11N TO 13.5N BETWEEN 73W AND 77W. 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 04N16W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 04N16W TO THE EQUATOR NEAR 29W. ISOLATED MODERATE CONVECTION IS FROM 02N-04N BETWEEN 19W-27W...AND S OF 02N BETWEEN 36W-50W. ...DISCUSSION... GULF OF MEXICO... WEST-NORTHWESTERLY FLOW ALOFT PREVAILS OVER THE GULF BASIN THIS EVENING WITH WATER VAPOR IMAGERY INDICATING MOSTLY DRY AIR AND SUBSIDENCE N OF 25N...AND INCREASED MIDDLE TO UPPER LEVEL MOISTURE S OF 25N. WITH OVERALL STABILITY IN CONTROL...AT THE SURFACE...A BROAD SURFACE RIDGE ANCHORED BY A 1026 MB HIGH CENTERED OFF THE SW LOUISIANA COAST NEAR 29N93W CONTINUES TO PROVIDE 10 TO 20 KT NORTHERLY WINDS ON THE EASTERN PERIPHERY OF THE RIDGE AND THE RE-ESTABLISHMENT OF E-SE RETURN FLOW ACROSS PORTIONS OF THE NW GULF ON THE WESTERN PERIPHERY OF THE RIDGING. SATELLITE IMAGERY INDICATES MOSTLY CLEAR SKIES ACROSS THE GULF WITH INCREASED SCATTERED STRATOCUMULUS CLOUDINESS ACROSS THE SE GULF THIS EVENING. THE HIGH IS FORECAST TO SLIDE EAST-NORTHEAST ACROSS NORTHERN FLORIDA INTO THE SW NORTH ATLC DURING THE NEXT 24 HOURS ALLOWING FOR E-SE RETURN FLOW TO ESTABLISH ACROSS THE ENTIRE BASIN AS ANOTHER AREA OF LOW PRESSURE BEGINS TO DEVELOP ACROSS THE CENTRAL AND SOUTHERN U.S. PLAINS OVER THE UPCOMING WEEKEND. CARIBBEAN SEA... AS OF 09/2100 UTC A STATIONARY FRONT IS ANALYZED FROM EASTERN CUBA NEAR 21N77W SW TO 19N81W THEN S TO OFFSHORE OF NICARAGUA NEAR 13N83W. SCATTERED SHOWERS ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THE FRONT AND REMAIN RELATIVELY SHALLOW DUE TO THE STRONGER MIDDLE TO UPPER LEVEL DYNAMICS REMAINING N OF 28N AND EXITING THE SW NORTH ATLC REGION TO THE NORTHEAST. TO THE WEST OF THE FRONT...NORTHERLY WINDS IN THE RANGE OF 15 TO 30 KT ARE NOTED AS STRONG HIGH PRESSURE REMAINS IN CONTROL ACROSS THE GULF OF MEXICO. AS THE FRONT BEGINS TO WEAKEN THROUGH LATE THURSDAY...N-NE WINDS ARE FORECAST TO DIMINISH AS THE HIGH MOVES INTO THE WESTERN NORTH ATLC. EAST OF THE FRONT...E-NE TRADES IN THE RANGE OF 15 TO 25 KT PERSIST WITHIN RELATIVELY CLEAR SKIES THIS EVENING. AS THE PRESSURE GRADIENT STRENGTHENS OVERNIGHT INTO THURSDAY...STRONGER WINDS OF GALE FORCE ARE EXPECTED WITHIN CLOSE PROXIMITY TO THE COLOMBIA COAST AND WITHIN THE COLOMBIA BASIN. ...HISPANIOLA... CURRENTLY A FEW ISOLATED SHOWERS AND TSTMS ARE OCCURRING ACROSS WESTERN PORTIONS OF THE ISLAND AND THIS ACTIVITY IS EXPECTED TO DIMINISH WITH THE LOSS OF DAYTIME HEATING AND INSTABILITY. OTHERWISE...AN UPPER LEVEL RIDGE AXIS EXTENDS OVER THE ISLAND FROM 15N75W NE TO 27N60W WITH WATER VAPOR IMAGERY INDICATING VERY DRY AND STABLE AIR ALOFT. HOWEVER...A FRONTAL BOUNDARY TO THE WEST CURRENTLY ACROSS EASTERN CUBA WILL MOVE TOWARD HISPANIOLA BY LATE THURSDAY AND BEGIN TO INCREASE MOISTURE AND PRECIPITATION PROBABILITIES FRIDAY. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY WITH AXIS EXTENDING ALONG THE EASTERN U.S. SEABOARD FROM NEW ENGLAND S-SW TO A BASE NEAR 29N80W. THIS TROUGHING SUPPORTS A COLD FRONT ANALYZED INTO THE DISCUSSION AREA NEAR 32N68W EXTENDING SW TO THE CENTRAL BAHAMAS...TO EASTERN CUBA...AND INTO THE NW CARIBBEAN SEA. WIDELY SCATTERED SHOWERS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE FRONT. FARTHER EAST...THE CENTRAL ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1029 MB HIGH CENTERED NEAR 39N43W AND FURTHER SUPPORTED ALOFT BY AN UPPER LEVEL RIDGE AXIS EXTENDING FROM OVER THE NORTH- CENTRAL CARIBBEAN SEA NEAR 19N71W NE TO BEYOND 32N55W. FINALLY...A MIDDLE TO UPPER LEVEL LOW AND ASSOCIATED TROUGHING IS CENTERED OVER THE EASTERN ATLC NEAR 30N34W. THE UPPER LEVEL LOW SUPPORTS A BROAD AREA OF LOWER PRESSURE AT THE SURFACE FOCUSED ON A 1013 MB LOW NEAR 29N23W AND A 1017 MB LOW CENTERED NEAR 33N34W. A COLD FRONT EXTENDS FROM THE 1017 MB LOW TO 30N35W TO 27N40W TO 26N46W. ISOLATED SHOWERS ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THE COLD FRONT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN