000 AXNT20 KNHC 130003 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU MAR 12 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 ALONG THE COAST OF COLOMBIA THIS AFTERNOON...HOWEVER ARE FORECAST TO RESUME TONIGHT CONTINUING THROUGH FRIDAY AFTERNOON...THEN RESUMING AGAIN SATURDAY MORNING. 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 06N10W TO 02N15W WHERE THE ITCZ BEGINS AND CONTINUES TO THE EQUATOR ALONG 40W TO THE COAST OF NORTHERN BRAZIL NEAR 01S46W. SCATTERED MODERATE CONVECTION AND TSTMS ARE WITHIN 100 NM EITHER SIDE OF THE ITCZ. ...DISCUSSION... GULF OF MEXICO... A 1013 MB LOW IS CENTERED AT 28N94W IN THE NORTHWESTERN GULF OF MEXICO ACCOMPANIED BY A COLD FRONT EXTENDING SOUTHWARD TO THE WESTERN YUCATAN PENINSULA AND A STATIONARY FRONT EXTENDING NORTHEASTWARD TO THE WEST LOUISIANA COAST. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 300 NM WEST OF THE COLD FRONT AND N OF 25N BETWEEN THE FLORIDA PANHANDLE AND SE LOUISIANA BASED UPON GEOSTATIONARY IMAGERY...LIGHTNING DATA...AND THE U.S. WSR-88D RADAR NETWORK. THE CONVECTION CONTINUES TO BE SUPPORTED BY FORCING FROM A HIGH AMPLITUDE MID- TO UPPER-LEVEL LONGWAVE TROUGH CENTERED NEAR 98W WITH A BASE OVER THE EAST PACIFIC WATERS NEAR 10N. SURFACE WINDS PEAK WEST OF THE COLD FRONT AT 15 KT. WINDS IN THE EASTERN HALF OF THE GULF ARE GENERALLY 15 KT FROM THE SE...EXCEPT N OF 27N BETWEEN 87W AND 91W. THE COLD FRONT WILL CONTINUE TO MOVE SLOWLY EASTWARD AND STALL IN THE CENTRAL GULF WHILE THE WEAK LOW MOVES NORTHWARD AND REACHES EASTERN TEXAS FRIDAY MORNING. THE FRONT IS FORECAST TO DISSIPATE SATURDAY MORNING AS THE LOW CONTINUES TO WEAKEN INLAND. 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 NORTHERN GULF OF MEXICO. CARIBBEAN SEA... GALE FORCE WINDS ALONG THE COAST OF COLOMBIA DIMINISHED THIS AFTERNOON BUT ARE RESUMING TONIGHT. SEE THE SPECIAL FEATURES SECTION FOR DETAILS. OTHERWISE...THE CARIBBEAN SEA HAS NO SURFACE FEATURES OF INTEREST NOR IS THERE ANY ORGANIZED DEEP CONVECTION. THE CONTINUATION OF A STRONG PRESSURE GRADIENT BETWEEN A LOW OVER NW COLOMBIA AND THE RIDGE OVER THE ATLC SUPPORT TRADES OF 20 TO 25 KT BETWEEN 65W AND 83W. TRADES OF 10 TO 15 KT DOMINATE ELSEWHERE. ALOFT...A BROAD HIGH AMPLITUDE UPPER RIDGE COVERS THE CARIBBEAN WITH AN AXIS ALONG 75W...WHICH IS PROMOTING SUBSIDENCE OVER THE CARIBBEAN. LITTLE CHANGE IS EXPECTED DURING THE NEXT TWO DAYS. ...HISPANIOLA... DEEP LAYER DRY AIR OVER THE ISLAND CONTINUE TO SUPPORT FAIR SKIES. HOWEVER...PASSING SHOWERS ARE POSSIBLE AS PATCHES OF SHALLOW MOISTURE CONTINUE TO MOVE WESTWARD WITH THE TRADES ACROSS THE CARIBBEAN. THESE CONDITIONS ARE FORECAST TO PERSIST THROUGH AT LEAST SATURDAY MORNING. ATLANTIC OCEAN... THE MAIN SURFACE FEATURE ACROSS THE ATLANTIC IS RIDGING EXTENDING SE FROM A 1039 MB HIGH NEAR 55N118W TO A 1025 MB HIGH OVER THE SW N ATLC NEAR 26N95W...AND ANOTHER RIDGE EXTENDING FROM A 1030 MB HIGH NEAR 47N22W SW TO NEAR 27N48W. A BROAD MID- TO UPPER-LEVEL TROUGH OVER THE WESTERN AND CENTRAL ATLC WITH BASE NEAR 30N CONTINUE TO SUPPORT A COLD FRONT WITH TAIL REACHING COASTAL WATERS OF SE GEORGIA. THE HIGH PRESSURE CENTER OVER THE SW N ATLC IS FORECAST TO DISSIPATE WITHIN THE NEXT SEVERAL HOURS GIVING THE SPACE FOR THE COLD FRONT TO ENTER THE AREA OF DISCUSSION FRIDAY MORNING. A SURFACE TROUGH EXTENDS FROM 27N72W TO 19N80W...THOUGH NO SIGNIFICANT WEATHER IS CURRENTLY ASSOCIATED WITH THIS FEATURE. VARIABLE WINDS OF 5 TO 15 KT DOMINATE THE BASIN W OF 30W N OF 22N...A TIGHTER PRESSURE GRADIENT SUPPORT WINDS OF 20 KT ALONG THE NW COAST OF AFRICA AND NORTHERN COASTAL WATERS OF THE GREATER ANTILLES. IN THE UPPER LEVELS...A CUT OFF LOW IS CENTERED NEAR 12N25W. SCATTERED SHOWERS ARE OCCURRING FROM 18N TO 23N BETWEEN 34W AND 40W IN ASSOCIATION WITH THE LOW...THOUGH NO SURFACE COMPONENT TO THE FEATURE IS CURRENTLY PRESENT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ RAMOS