000 AXNT20 KNHC 071754 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT THU MAY 07 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... AS OF 07/1500 UTC...A 1007 MB LOW IS CENTERED NEAR 31N78W WITH A SURFACE TROUGH AXIS EXTENDING FROM THE LOW CENTER TO 27N75W TO 23N76W. THIS LOW IS BEING SUPPORTED IN THE MIDDLE TO UPPER LEVELS BY A TROUGH THAT EXTENDS FROM THE TENNESSEE VALLEY TO THE EAST COAST OF FLORIDA. THE LOW HAS BECOME BETTER DEFINED SINCE WEDNESDAY WITH INCREASING ORGANIZATION OF THUNDERSTORMS ASSOCIATED WITH THIS SYSTEM. SCATTERED MODERATE CONVECTION IS WITHIN 200 NM NORTHWEST OF THE LOW CENTER. A BAND OF MODERATE CONVECTION EXTENDS FROM NORTH TO SOUTH WITHIN 50 NM OF A LINE FROM 25N71W TO 31N72W. GALE FORCE WINDS WERE REPORTED BY AIRCRAFT RECONNAISSANCE AND THEREFORE A GALE WARNING HAS BEEN ISSUED FOR OFFSHORE WATERS WITHIN 60 NM SOUTHWEST OF THE LOW CENTER. THE LOW IS EXPECTED TO DRIFT GENERALLY NORTHWARD OVER THE NEXT COUPLE OF DAYS. HEAVY RAIN IS EXPECTED OVER PORTIONS OF THE COASTAL SOUTHEASTERN UNITED STATES FOR THE NEXT SEVERAL DAYS REGARDLESS OF WHAT DEVELOPS OUT OF THIS SYSTEM. THE MOST RECENT TROPICAL WEATHER OUTLOOK GIVES THE CHANCE OF DEVELOPMENT OF THIS SYSTEM INTO A TROPICAL OR SUBTROPICAL CYCLONE IN THE NEXT 48 HOURS AS HIGH. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N15W TO 06N23W...WHERE THE ITCZ BEGINS AND CONTINUES THROUGH 03N30W AND SOUTH OF THE EQUATOR NEAR 39W. SCATTERED MODERATE CONVECTION IS FROM THE EQUATOR TO 05N BETWEEN 25W AND 49W...AND FROM THE EQUATOR TO 13N BETWEEN 16W AND 25W. ...DISCUSSION... GULF OF MEXICO... A MIDDLE TO UPPER LEVEL RIDGE AXIS EXTENDS FROM MEXICO NORTHEASTWARD OVER THE WESTERN GULF. A MIDDLE TO UPPER LEVEL TROUGH IS OVER THE SOUTHEASTERN US. NORTHWESTERLY FLOW AND DRY AIR ALOFT IS OVER THE GULF BASIN BETWEEN THESE TWO FEATURES. THESE STABLE CONDITIONS COMBINED WITH WEAK HIGH PRESSURE OF 1019 MB CENTERED NEAR 29N85W IS SUPPORTING FAIR WEATHER ACROSS THE ENTIRE GULF BASIN THIS AFTERNOON. ANTICYCLONIC FLOW AT THE SURFACE IS OCCURRING AROUND THE SURFACE HIGH...WITH 10 TO 15 KT EAST TO SOUTHEASTERLY FLOW OVER THE MAJORITY OF THE GULF. VERY LITTLE CHANGE IS EXPECTED IN WEATHER CONDITIONS OVER THE GULF OVER THE NEXT 48 HOURS. CARIBBEAN SEA... A BROAD MIDDLE TO UPPER LEVEL TROUGH IS CENTERED ALONG 80W OVER THE CARIBBEAN. GENERALLY DRY AND STABLE CONDITIONS PREVAIL UNDER THIS TROUGH ACROSS THE BASIN. THE ONLY EXCEPTION IS A NEWLY IDENTIFIED SURFACE TROUGH THAT EXTENDS FROM NEAR 21N85W TO HONDURAS NEAR 15N85W. THIS FEATURE WILL BE ADDED TO THE UPCOMING 1800 UTC MAP. ISOLATED MODERATE CONVECTION IS WITHIN 50 NM OF THE TROUGH AXIS. 15 TO 20 KT TRADE WINDS ARE OVER THE MAJORITY OF THE BASIN WITH AN AREA OF WINDS TO 25 KT OVER THE CENTRAL CARIBBEAN FROM THE NORTHERN COAST OF COLOMBIA TO 16N BETWEEN 70W AND 77W. OVER THE NEXT 24 HOURS THE TROUGH IS EXPECTED TO MOVE SLOWLY NORTHWEST WITH CONVECTION POSSIBLE FROM THE NORTHERN COAST OF HONDURAS TO THE YUCATAN PENINSULA. OTHERWISE...FAIR WEATHER WILL CONTINUE ACROSS THE BASIN. ...HISPANIOLA... SOUTHWESTERLY FLOW JUST OFF THE SURFACE IS OCCURRING OVER THE WESTERN HALF OF THE ISLAND ASSOCIATED WITH THE FLOW AROUND THE LOW PRESSURE SYSTEM OFF THE COAST OF NORTHERN FL/GA. THIS SOUTHWESTERLY FLOW IS CONVERGING WITH THE EASTERLY TRADE WINDS TO PRODUCE ISOLATED THUNDERSTORMS OVER THE HIGHER TERRAIN OF THE WESTERN HALF OF THE ISLAND TODAY. THIS FLOW REGIME MAY CONTINUE THROUGH SATURDAY AS THE LOW MOVES VERY LITTLE. THEREFORE...EXPECT ISOLATED THUNDERSTORMS TO REMAIN POSSIBLE OVER THE WESTERN PORTION OF THE ISLAND THROUGH SATURDAY. ATLANTIC OCEAN... THE LOW PRESSURE SYSTEM JUST OFFSHORE NORTHERN FL/GA IS DISCUSSED IN THE SPECIAL FEATURES SECTION. SURFACE RIDGING ANCHORED BY A 1026 MB HIGH CENTERED NEAR 30N49W SUPPORTS ANTICYCLONIC FLOW AND GENERALLY FAIR WEATHER EAST OF 70W AND N OF 05N OVER THE TROPICAL NORTHERN ATLC. A SURFACE TROUGH IS OVER THE EASTERN ATLC FROM 30N20W TO 24N32W. THIS TROUGH IS VOID OF DEEP CONVECTION. OVER THE NEXT TWO DAYS THE LOW WILL MOVE SLOWLY NORTHWARD WITH ONGOING CONVECTION EXPECTED WITHIN 200 NM OF THE LOW CENTER...AND SOUTH AND EAST OF THE LOW ASSOCIATED WITH AN ELONGATED SURFACE TROUGH. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LATTO