000 AXNT20 KNHC 291751 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE APR 29 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 07N12W TO 01N20W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 01N20W TO THE EQUATOR NEAR 22W. ISOLATED MODERATE CONVECTION IS S OF 08N BETWEEN 11W-21W...AND S OF 05N BETWEEN 28W-37W. ...DISCUSSION... GULF OF MEXICO... A VERY BROAD AND VIGOROUS MIDDLE TO UPPER LEVEL LOW IS CENTERED OVER THE MID-MISSISSIPPI RIVER VALLEY THIS AFTERNOON THAT SUPPORTS A 994 MB SURFACE LOW CENTERED OVER NW MISSOURI. THE PARTIALLY OCCLUDED LOW EXTENDS A COLD FRONT ACROSS THE OHIO RIVER VALLEY THAT BECOMES STATIONARY FROM NORTHERN MISSISSIPPI SW TO EASTERN TEXAS AND SW ALONG THE TEXAS GULF COAST. CURRENTLY THE FRONT REMAINS RELATIVELY VOID OF DEEP CONVECTION AS IT NEARS THE NW GULF WATERS...HOWEVER A SQUALL LINE OF TSTMS ARE OCCURRING TO THE EAST WITHIN 60 NM EITHER SIDE OF A LINE FROM SW GEORGIA NEAR 32N84W TO 29N88W...INCLUDING A PORTION OF THE NE GULF AND INLAND AREAS OF ALABAMA AND THE FLORIDA PANHANDLE. OTHERWISE...THE REMAINDER OF THE GULF IS UNDER MOSTLY CLEAR SKIES S OF 27N AS STRONG SOUTH-SOUTHEAST FLOW PERSISTS IN THE RANGE OF 10 TO 20 KT WITH WINDS APPEARING TO VEER SLIGHTLY SOUTH- SOUTHWESTERLY ACROSS THE NW GULF WATERS THIS AFTERNOON AHEAD OF THE APPROACHING COLD FRONT. THE COLD FRONT IS EXPECTED TO EMERGE OFF THE TEXAS AND LOUISIANA COASTS THIS EVENING INTO THE OVERNIGHT HOURS INTRODUCING NORTH-NORTHEASTERLY WINDS ACROSS THE WESTERN GULF THROUGH EARLY THURSDAY. BY THURSDAY...THE FRONT IS EXPECTED TO BECOME STATIONARY DRAPED FROM THE FLORIDA BIG BEND REGION SW TO THE BAY OF CAMPECHE. CARIBBEAN SEA... WESTERLY FLOW ALOFT PREVAILS OVER THE CARIBBEAN WITH WATER VAPOR IMAGERY INDICATING RELATIVELY DRY AND STABLE CONDITIONS IN THE MIDDLE TO UPPER LEVELS THIS AFTERNOON. THIS IS RESULTING IN RELATIVELY FAIR SKIES...HOWEVER WITH A STRONG PRESSURE IN PLACE DUE TO A RIDGE ACROSS THE SW NORTH ATLC REGION...TRADES PERSIST IN THE RANGE OF 15 TO 25 KT...STRONGEST BETWEEN 69W-78W AND IN THE GULF OF HONDURAS. ELSEWHERE...LOW-LEVEL MOISTURE CONVERGENCE INCREASES ACROSS THE SW CARIBBEAN AND CENTRAL AMERICA S OF 12N AS SCATTERED SHOWERS AND TSTMS ARE OCCURRING ACROSS PANAMA AND COSTA RICA...INCLUDING THE ADJACENT COASTAL WATERS ON BOTH CARIBBEAN WATERS AND EASTERN PACIFIC WATERS. THIS ACTIVITY IS LIKELY ENHANCED DUE TO THE CLOSE PROXIMITY OF THE MONSOON TROUGH AXIS EXTENDING ALONG 08N/09N. ...HISPANIOLA... CURRENTLY DRY AND STABLE WESTERLY FLOW ALOFT IS PROVIDING FAIR CONDITIONS ACROSS THE ISLAND. GIVEN PEAK AFTERNOON HEATING AND INSTABILITY...A FEW ISOLATED SHOWERS AND TSTMS ARE POSSIBLE THIS AFTERNOON INTO THE EVENING HOURS. ANY ONGOING CONVECTION WILL LIKELY DIMINISH GRADUALLY LATE EVENING INTO THE OVERNIGHT HOURS. ATLANTIC OCEAN... OVERALL RIDGING ALOFT IS NOTED ON WATER VAPOR IMAGERY OVER THE SW NORTH ATLC THAT SUPPORTS A 1020 MB HIGH CENTERED WEST OF BERMUDA NEAR 31N69W. HOWEVER...WATER VAPOR IMAGERY ALSO INDICATES A VERY WEAK MID-LEVEL SHORTWAVE TROUGH AND ASSOCIATED ENERGY OVER THE BAHAMAS NEAR 23N75W. WHILE NO SURFACE-BASED BOUNDARY OR FRONT IS IN THE VICINITY...THE MID-LEVEL ENERGY IS GENERATING AN AREA OF SCATTERED SHOWERS AND TSTMS FROM 21N-24N BETWEEN 74W-79W. FARTHER EAST...A MIDDLE TO UPPER LEVEL LOW IS CENTERED NEAR 37N57W THAT REFLECTS TO THE SURFACE AS A 1000 MB LOW CENTERED NEAR 37N59W THAT CONTINUES TO DRIFT EAST-SOUTHEAST. THE ASSOCIATED COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N51W EXTENDING SW TO 29N58W. A SURFACE TROUGH IS ANALYZED SOUTH OF THE COLD FRONT FROM 29N53W SW TO 25N63W. TO THE EAST OF THE BOUNDARIES...ONLY A FEW ISOLATED SHOWERS ARE OCCURRING FROM 23N- 28N BETWEEN 44W-52W. OTHERWISE...THE REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1023 MB HIGH CENTERED NEAR 33N31W AND A 1024 MB HIGH CENTERED NEAR 37N19W. THE SURFACE RIDGE AXIS EXTENDS FROM THE 1023 MB HIGH SW TO 20N50W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN