000 AXNT20 KNHC 222353 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT MAR 22 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 2345 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLC NEAR 7N11W SW TO 2N20W. THE ITCZ AXIS EXTENDS FROM 2N20W TO 2N30W TO THE EQUATOR AT 25W THEN TO THE COAST OF SOUTH AMERICA NEAR 2S43W. SCATTERED MODERATE CONVECTION WAS NOTED WITHIN 60-90 NM OF THE ITCZ BETWEEN 30W-43W...AND ELSEWHERE S OF 3N W OF 40W. ...DISCUSSION... GULF OF MEXICO... UPPER LEVEL FLOW OVER THE GULF REMAINED ANTICYCLONIC WITH A FLAT RIDGE AXIS ALONG 90W. SUBSIDING AIR PREVAILED OVER THE SOUTHERN THIRD OF THE GULF WITH MID TO UPPER LEVEL MOISTURE NOTED N OF 24N. THIS MOISTURE WAS BEING ADVECTED BY STRONG WESTERLY WINDS. GRIDDED WINDS AT 250 MB FROM THE GFS MODEL WERE ON THE ORDER OF 100-110 KT OVER THE GULF COAST. GLOBAL MODEL GUIDANCE INDICATES A NARROW EAST-WEST RIBBON OF MID-LEVEL VORTICITY STRETCHING FROM WEST TEXAS TO THE MISSISSIPPI RIVER DELTA WHICH SUPPORTED A SURFACE TROUGH EXTENDING FROM NEAR GALVESTON TEXAS ESE THROUGH 28N90W TO 27N85W. THE TROUGH SEPARATED LIGHT ENE WINDS FROM SOUTHERLY WINDS. BROKEN TO OVERCAST LOW CLOUDS WERE NOTED WITHIN 60-120 NM N OF THE TROUGH WITH SCATTERED SHOWERS CONCENTRATED WITHIN 60 NM OF 27N86.5W. AS OF 2100 UTC A 1017 MB SFC HIGH WAS NOTED NEAR 28N85W. MOSTLY FAIR CONDITIONS PREVAILED ELSEWHERE S OF THE TROUGH. THE SURFACE TROUGH IS EXPECTED TO GRADUALLY BECOME DIFFUSE OVERNIGHT INTO SUNDAY AS THE NEXT FRONTAL BOUNDARY APPROACHES THE TEXAS AND LOUISIANA COAST. THIS FRONT IS FORECAST TO EMERGE OFF THE COAST SUNDAY AFTERNOON INTO THE EVENING HOURS. WINDS BEHIND THE FRONT WILL SHIFT NORTHEASTERLY AND REMAIN IN THE RANGE OF 15 TO 20 KT DUE TO THE OVERALL LACK OF MIDDLE TO UPPER LEVEL FORCING DYNAMICS. A STRONGER SECONDARY COLD FRONT IS EXPECTED EARLY TUESDAY. CARIBBEAN... A BROAD FLAT UPPER RIDGE COVERS THE WESTERN AND CENTRAL CARIBBEAN WHILE A WEAK TROUGH EXTENDS SOUTHWARD ALONG 58W...JUST E OF THE WINDWARD ISLANDS. GENERALLY WEST TO NORTHWEST UPPER LEVEL WINDS PREVAIL OVER MUCH OF THE CARIBBEAN BASIN WITH WATER VAPOR IMAGERY INDICATING DRY STABLE AIR AT THE MID AND UPPER LEVELS ACROSS THE ENTIRE BASIN WHICH IS SUPPRESSING THE DEVELOPMENT OF ANY DEEP CONVECTION. HOWEVER...A SMALL PORTION OF THE NORTH-CENTRAL CARIBBEAN...INCLUDING WESTERN HISPANIOLA...THE WINDWARD PASSAGE...AND JAMAICA IS UNDER THE INFLUENCE OF A REMNANT FRONTAL BOUNDARY NOW ANALYZED AS A SURFACE TROUGH EXTENDING FROM THE CENTRAL ATLC TO THE ENTRANCE OF THE WINDWARD PASSAGE. ISOLATED SHOWERS ARE POSSIBLE WITHIN 60 NM EITHER SIDE OF A LINE FROM 21N72W TO 18N78W. THE BOUNDARY IS EXPECTED TO DISSIPATE OVER THE NEXT 24 HOURS. FINALLY...THE OTHER SIGNIFICANT IMPACT IS STRONG TRADE WINDS OCCURRING ACROSS THE SOUTH-CENTRAL CARIBBEAN S OF 15N BETWEEN 67W-78W. THESE TRADES RANGE FROM 20 TO 25 KT AND ARE EXPECTED TO PERSIST THROUGH TUESDAY. HISPANIOLA... LATE DAY VISIBLE SATELLITE IMAGERY SHOWED SCATTERED LOW CLOUDS ACROSS THE ISLAND WITH ISOLATED SHOWERS/THUNDERSTORM ALONG THE N FACING SLOPES OF THE ISLANDS ON THE BORDER OF HAITI AND THE DOMINICAN REPUBLIC. THIS CLOUDINESS IS BEING SUPPORTED BY LINGERING MOISTURE ASSOCIATED WITH A SURFACE TROUGH JUST TO THE NW OF THE ISLAND. OTHERWISE... NORTHWESTERLY WINDS ALOFT PREVAIL AND WILL MAINTAIN A FAIRLY DRY AND STABLE ENVIRONMENT OVER THE NEXT FEW DAYS. WITH THE BOUNDARY IN PLACE AND TRENDING TOWARD DISSIPATION...THE THREAT OF PRECIPITATION GRADUALLY DECREASES THROUGH THE OVERNIGHT HOURS INTO SUNDAY. ATLANTIC... WEST-NORTHWESTERLY FLOW ALOFT IS NOTED OVER THE SW NORTH ATLC WITH WATER VAPOR IMAGERY INDICATING A FAIR AMOUNT OF PROGRESSIVE MIDDLE TO UPPER LEVEL CLOUDINESS AND MOISTURE CONTINUING TO MOVE EAST N OF 28N. MOST OF THIS MOISTURE IS ABOVE A FAIRLY BROAD SURFACE RIDGE ANCHORED BY A 1024 MB HIGH CENTERED W OF BERMUDA NEAR 32N68W. WITH RETURN FLOW ON THE WESTERN PERIPHERY OF THE RIDGING...LOW-LEVEL MOISTURE CONVERGENCE AND AID FROM MARGINAL MID-LEVEL DYNAMICS ARE GENERATING WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 90-120 NM EAST OF A SURFACE TROUGH WHICH EXTENDS FROM SAVANNAH GEORGIA SOUTHWARD ALONG THE FLORIDA E COAST TO NEAR NAPLES. AS OF 21 UTC...A WEAK 1014 MB LOW DEVELOPED OVER EXTREME NE FLORIDA NEAR DAYTONA BEACH. FARTHER EAST...A MIDDLE TO UPPER LEVEL TROUGH AXIS EXTENDS SOUTHWARD ALONG 53W TO A BASE NEAR 20N. THIS TROUGHING SUPPORTS A COLD FRONT ANALYZED FROM 32N51W TO 28N60W AND A PRE- FRONTAL SURFACE TROUGH FROM 31N50W SW TO 25N60W TO THE ENTRANCE OF THE WINDWARD PASSAGE. ISOLATED SHOWERS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF BOTH THE COLD FRONT AND SURFACE TROUGH BOUNDARIES. FINALLY...THE EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1030 MB HIGH CENTERED WELL SW OF THE AZORES NEAR 31N32W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ COBB