000 AXNT20 KNHC 140003 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI MAR 13 2015 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. ...SPECIAL FEATURES... ...GALE WARNING FOR THE SW CARIBBEAN... GALE WINDS DIMINISHED OVER COLOMBIA COASTAL WATERS THIS AFTERNOON...HOWEVER ARE FORECAST TO RESUME TONIGHT CONTINUING THROUGH SATURDAY AFTERNOON...THEN RESUMING AGAIN SATURDAY NIGHT. THE HIGH WINDS ARE BEING CAUSED BY THE STRONG PRESSURE GRADIENT BETWEEN A 1007 MB LOW OVER NORTHERN COLOMBIA AND A SURFACE RIDGE OVER THE W ATLC...IN COMBINATION WITH THE TYPICAL TOPOGRAPHICAL WIND ENHANCEMENTS NORTH OF COLOMBIA. PLEASE SEE THE LATEST HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLANTIC NEAR 10N14W TO 03N17W WHERE THE ITCZ BEGINS AND CONTINUES ALONG THE EQUATOR NEAR 30W TO THE COAST OF NORTHERN BRAZIL NEAR 01S48W. SCATTERED MODERATE TO STRONG CONVECTION IS S OF THE MONSOON TROUGH FROM 01N-05N BETWEEN 08W-15W. SCATTERED TO ISOLATED MODERATE CONVECTION IS WITHIN 150 NM EITHER SIDE OF THE ITCZ. ...DISCUSSION... GULF OF MEXICO... A 1013 MB LOW IS CENTERED OVER SE LOUISIANA ACCOMPANIED BY A STATIONARY FRONT EXTENDING S-SW TO THE WEST COAST OF NORTHERN YUCATAN PENINSULA NEAR 21N90W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS OBSERVED AHEAD OF THE FRONT E OF 88W N OF 26N BASED UPON GEOSTATIONARY IMAGERY...LIGHTNING DATA...AND THE U.S. WSR-88D RADAR NETWORK. THE CONVECTION IS SUPPORTED BY FORCING FROM A HIGH AMPLITUDE MID-TO UPPER-LEVEL LONGWAVE TROUGH CENTERED OVER MEXICO. A 1017 MB HIGH IS BEHIND THE FRONT CENTERED NEAR 24N94W...WHICH IS PROVIDING VARIABLE WINDS OF 5 TO 10 KT S OF 27N...WESTERLY FLOW OF 15 KT DOMINATES N OF 27N WEST OF THE FRONT. A SURFACE RIDGE OVER THE W ATLC EXTENDS SW ACROSS THE FLORIDA PENINSULA TO THE EASTERN GULF AND PROVIDES SE FLOW OF 15 TO 25 KT E OF THE STATIONARY FRONT...AS SEEN IN AN EARLIER ASCAT SCATTEROMETER PASS. OVER THE NEXT TWO DAYS...THE PORTION OF THE FRONT OVER THE NORTHERN GULF WILL TRANSITION TO A COLD FRONT WHILE THE SOUTHERN PORTION OF IT WILL SLOWLY RETROGRADE TO THE WESTERN BASIN AS A STATIONARY FRONT. THE ADVECTION OF ABUNDANT MOISTURE ALONG WITH FORCING BY THE UPPER-LEVEL TROUGH SHOULD CONTINUE TO PROVIDE THE POTENTIAL FOR CONVECTION DURING THE NEXT COUPLE OF DAYS IN THE WESTERN AND CENTRAL GULF OF MEXICO INCLUDING THE COAST OF MEXICO FROM THE BAY OF CAMPECHE TO THE U.S. GULF COAST FROM TEXAS TO THE FLORIDA PANHANDLE. CARIBBEAN SEA... OUTSIDE NEAR GALE CONDITIONS ALONG THE COAST OF COLOMBIA REFERENCED ON THE SPECIAL FEATURES SECTION...THE CARIBBEAN SEA HAS NO SURFACE FEATURES OF INTEREST NOR IS THERE ANY ORGANIZED DEEP CONVECTION. A BROAD HIGH AMPLITUDE UPPER RIDGE COVERS THE CARIBBEAN WITH AN AXIS ALONG 74W...WHICH IS PROMOTING SUBSIDENCE OVER THE CARIBBEAN. THE AFOREMENTIONED STRONG PRESSURE GRADIENT FORCING NEAR GALE CONDITIONS ON COLOMBIA ADJACENT WATERS ARE ALSO FORCING E TO NE TRADEWINDS OF 20 TO 25 KT ACROSS THE EASTERN AND CENTRAL CARIBBEAN. TRADES OF 15 KT DOMINATE OVER THE NW BASIN. LITTLE CHANGE IS EXPECTED DURING THE NEXT TWO DAYS. ...HISPANIOLA... GENERALLY FAIR SKIES WITH POSSIBLE ISOLATED PASSING SHOWERS DOMINATE THE ISLAND THIS EVENING. WINDS ALONG THE COASTS WILL BE A BRISK 20-25 KT OUT OF THE EAST-NORTHEAST. THESE CONDITIONS WILL PERSIST THROUGH AT LEAST SUNDAY MORNING. ATLANTIC OCEAN... A COLD FRONT EXTENDS FROM 30N47W TO 25N59W TO 25N72W WITH POSSIBLE SCATTERED TO ISOLATED SHOWERS WITHIN 60 NM EITHER SIDE OF THE FRONT. WINDS BEHIND THE FRONT ARE FROM THE N-NE OF 15-20 KT...AS OBSERVED BY AN EARLIER SCATTEROMETER PASS. THE FRONT WILL CONTINUE TO MOVE EASTWARD THE NEXT TWO DAYS...TRANSITIONING TO A STATIONARY FRONT S OF 26N W OF 50W BY SATURDAY MORNING. ELSEWHERE...THE ATLANTIC CONTINUES TO BE DOMINATED BY RIDGING EXTENDING FROM A 1036 MB HIGH NEAR 40N71W SOUTHWARD TO A RIDGELINE ALONG 23N AND ANOTHER RIDGE OVER THE E ATLC ANCHORED BY A 1032 MB HIGH NEAR 49N09W. TRADEWINDS ARE GENERALLY NE 15-20 KT ACROSS MOST OF THE REGION E AND S OF THE FRONT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR