000 AXNT20 KNHC 110552 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT WED MAR 11 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...SPECIAL FEATURES... ...GALE WARNING FOR THE SW CARIBBEAN... A GALE WARNING IS IN EFFECT FOR THE COASTAL WATERS OF COLOMBIA FROM 11N TO 14N BETWEEN 74W AND 77W. THE 0152Z AND 0238Z ASCAT SCATTEROMETER PASSES SHOWED 35 KT ENE WINDS FROM 11.5 TO 12.5N BETWEEN 74 TO 76W. THESE HIGH WINDS ARE BEING CAUSED BY THE STRONG PRESSURE GRADIENT BETWEEN A 1005 MB LOW OVER NORTHERN COLOMBIA AND A 1030 MB BERMUDA HIGH WELL TO THE NORTHEAST...IN COMBINATION WITH THE TYPICAL TOPOGRAPHICAL WIND ENHANCEMENTS NORTH OF COLOMBIA. GALE CONDITIONS WILL CONTINUE THROUGH THU EVENING. 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 5N10W TO 3N13W WHERE THE ITCZ BEGINS AND CONTINUES TO THE EQUATOR NEAR 26W THEN TO SOUTH AMERICA NEAR 1S45W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION EXISTS WITHIN 60 NM THE ITCZ WEST OF 37W. ...DISCUSSION... GULF OF MEXICO... A MODERATE COLD FRONT IS PUSHING SLOWLY TO THE SOUTHEAST ACROSS THE GULF THIS EVENING. IT CURRENTLY EXTENDS FROM THE COAST OF LOUISIANA SOUTHWESTWARD TO THE COAST OF MEXICO BETWEEN TAMPICO AND VERACRUZ. SCATTERED MODERATE CONVECTION IS OBSERVED FROM THE ALTAMIRA RADAR AND LIGHTNING DATA ALONG THE FRONT TO THE MEXICAN COAST AND INLAND SOUTH OF 25N. ISOLATED MODERATE CONVECTION IS OBSERVED FROM THE U.S. WSR-88D RADAR NETWORK WITHIN 120 NM WEST OF THE FRONT NORTH OF 25N. THE CONVECTION IS LIKELY SUPPORTED BY FORCING FROM A HIGH AMPLITUDE MID TO UPPER LEVEL TROUGH CENTERED OVER WESTERN MEXICO. A PRE-FRONTAL TROUGH IS ANALYZED IN THE SOUTHWESTERN GULF...WHILE A SECOND TROUGH EXTENDS FROM THE YUCATAN OF MEXICO TO THE STRAITS OF FLORIDA. HOWEVER...NEITHER OF THESE FEATURES ARE ASSOCIATED WITH ANY SIGNIFICANT WEATHER. SURFACE WINDS WEST OF THE FRONT ARE GENERALLY 15-20 KT NE...WHILE WINDS IN THE EASTERN HALF OF THE GULF ARE 10-15 KT SE. OVER THE NEXT TWO DAYS...THE FRONT ESSENTIALLY BECOMES STATIONARY IN THE WESTERN THIRD OF THE GULF WHILE A WEAK LOW MOVES QUICKLY NORTHWARD ALONG THE FRONT AND REACHES THE GULF COAST LATE THURSDAY. THE ADVECTION OF ABUNDANT MOISTURE ALONG WITH FORCING BY THE UPPER LEVEL TROUGH SHOULD CONTINUE THE POTENTIAL FOR CONVECTION DURING THE NEXT COUPLE OF DAYS IN THE WESTERN GULF OF MEXICO INCLUDING THE COAST OF MEXICO FROM THE BAY OF CAMPECHE TO THE TEXAS AND LOUISIANA COASTS. CARIBBEAN SEA... OUTSIDE OF THE GALE CONDITION DESCRIBED ABOVE...THE CARIBBEAN SEAS HAVE 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 77W...WHICH IS PROMOTING SUBSIDENCE OVER THE CARIBBEAN. THE AFOREMENTIONED STRONG PRESSURE GRADIENT FORCING THE GALE CONDITIONS NEAR COLOMBIA ARE ALSO FORCING E TO NE TRADEWINDS OF 20 TO 30 KT ACROSS THE EASTERN TWO THIRDS OF THE CARIBBEAN. LITTLE CHANGE IS EXPECTED DURING THE NEXT TWO DAYS. ...HISPANIOLA... GENERALLY FAIR SKIES WITH POSSIBLE ISOLATED FAST-MOVING SHOWERS DOMINATE THE ISLAND THIS EVENING. THESE CONDITIONS WILL PERSIST THROUGH AT LEAST THURSDAY NIGHT. ATLANTIC OCEAN... THE MAIN SURFACE FEATURE ACROSS THE ATLANTIC IS THE RIDGING EXTENDING FROM A 1030 MB BERMUDA HIGH NEAR 33N62W TO A 1029 MB AZORES HIGH NEAR 33N25W. TRADEWINDS ARE GENERALLY NE 10-20 KT ACROSS MOST OF THE REGION WITH 25-30 KT E WINDS OCCURRING JUST NORTH OF THE GREATER ANTILLES. A SURFACE TROUGH EXTENDS FROM 30N43W TO 26N53W...THOUGH NO SIGNIFICANT WEATHER IS CURRENTLY ASSOCIATED WITH THIS FEATURE. IN THE UPPER-LEVELS...A CUT OFF LOW IS CENTERED NEAR 20N45W. SCATTERED SHOWERS ARE OCCURRING FROM 18-23N BETWEEN 40-48W IN ASSOCIATION WITH THE LOW...THOUGH NO SURFACE COMPONENT TO THE FEATURE IS CURRENTLY PRESENT. DURING THE NEXT COUPLE OF DAYS...THE UPPER-LEVEL LOW WILL DRIFT SLOWLY EASTWARD AND OCCASIONALLY PRODUCE SOME CONVECTION...BUT NO SIGNIFICANT SURFACE FEATURES ARE ANTICIPATED TO FORM. BY THURSDAY NIGHT...A NEW COLD FRONT WILL REACH THE NORTHERN BORDER OF 32N. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LANDSEA