000 AXNT20 KNHC 172338 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN MAY 17 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 2315 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLC NEAR 19N16W ALONG 9N19W TO 6N22W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 3N31W 2N41W TO SOUTH AMERICA NEAR 00N50W. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 4N TO THE EQUATOR BETWEEN 7W-11W...FROM 5N-7N BETWEEN 12W-17W...AND FROM 4N-6N BETWEEN 32W-36W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM N OF THE MONSOON TROUGH/ITCZ BETWEEN 21W-27W...WITHIN 90 NM S OF THE ITCZ BETWEEN 28W-33W...AND WITHIN A 75 NM RADIUS OF 3N20W. ...DISCUSSION... GULF OF MEXICO... AN UPPER RIDGE ANCHORED IN THE E PACIFIC REGION COVERS THE SW GULF S OF 26N W OF 90W. A SECOND BROAD UPPER RIDGE IS ANCHORED OVER S FLORIDA AND EXTENDS A RIDGE AXIS N TO THE GREAT LAKES. A SHORTWAVE UPPER TROUGH IS MOVING THROUGH THE NW GULF EXTENDING FROM SE LOUISIANA TO 24N88W. A STRONG UPPER LOW IS OVER THE NORTHERN PLAIN STATES SUPPORTING A STRONG COLD FRONT THAT EXTENDS S TO OVER CENTRAL TEXAS. THIS FRONT HAS BEEN GENERATING SCATTERED SHOWERS/THUNDERSTORMS INLAND OVER THE LOWER MISSISSIPPI VALLEY WITH ISOLATED SHOWERS DEVELOPING IN THE NW GULF N OF 29N W OF 93W THAT ARE MOVING INLAND OVER LOUISIANA. THE STRONG EASTERLY WINDS ARE PUSHING A SEABREEZE ACROSS FLORIDA WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ALONG THE W COAST OF FLORIDA FROM NAPLES TO THE BIG BEND AREA. THIS ACTIVITY IS MOVING INTO THE COASTAL WATERS OF THE GULF. A WEAKENING UPPER LOW REMAINS ALONG THE S COAST OF CUBA AND IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INLAND AND WITHIN 45 NM ALONG THE W END OF CUBA. THIS IS LEAVING THE REMAINDER OF THE GULF UNDER CLEAR SKIES THIS EVENING. A SURFACE RIDGE EXTENDS FROM A 1028 MB HIGH IN THE W ATLC THROUGH A WEAKER 1025 MB HIGH OVER SOUTH CAROLINA THEN SW TO THE S COAST OF TEXAS. A SURFACE HIGH WILL DEVELOP OVER THE NE GULF MON NIGHT AND WILL MEANDER TO OVER N/CENTRAL AND NE GULF THROUGH THU. CARIBBEAN SEA... A WEAKENING UPPER LOW IS ALONG THE S COAST OF CUBA NEAR 21N81W AND COUPLED WITH THE EASTERLY TRADE WINDS ARE GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ALONG THE S COAST OF CUBA AND INTO THE IMMEDIATE COASTAL WATERS OF THE NW CARIBBEAN. THE REMAINDER OF THE CARIBBEAN IS DOMINATED BY AN UPPER RIDGE. THIS UPPER RIDGE CONTINUES TO ADVECT TROPICAL MOISTURE ACROSS PANAMA TO CENTRAL AMERICA GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ACROSS THE SW CARIBBEAN S OF 14N W OF 75W. THE EASTERLY TRADE WINDS ARE GENERATING AFTERNOON/ EVENING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ACROSS PUERTO RICO...HISPANIOLA...AND JAMAICA. FRESH TO STRONG TRADE WINDS ARE EXPECTED IN THE S/CENTRAL CARIBBEAN THROUGH MON NIGHT. MODERATE TO FRESH TRADE WINDS WILL PREVAIL ACROSS THE REMAINDER OF THE AREA S OF 17N WITH MODERATE TRADE WINDS EXPECTED N OF 17N. ...HISPANIOLA... AFTERNOON/EVENING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ACROSS THE ISLAND THIS EVENING. WESTERLY FLOW ALOFT WILL CONTINUE THROUGH THU. EXPECT DAYTIME HEATING AND OROGRAPHIC LIFTING COUPLED WITH LINGERING MOISTURE TO GENERATE AFTERNOON SHOWERS/THUNDERSTORMS OVER THE NEXT DEW DAYS. ATLANTIC OCEAN... A SURFACE RIDGE COVERS THE W ATLC W OF 60W ANCHORED BY A 1028 MB HIGH ABOUT 400 NM E OF CHARLESTON SOUTH CAROLINA AND EXTENDS TO A WEAKER 1025 MB HIGH INLAND OVER SOUTH CAROLINA THEN CONTINUES TO OVER THE GULF OF MEXICO. A BROAD UPPER TROUGH COVERS MOST OF THE W AND INTO THE CENTRAL ATLC SUPPORTING A COLD FRONT THAT ENTERS THE REGION NEAR 32N45W AND EXTENDS TO 25N52W WHERE IT BECOMES STATIONARY ALONG 20N66W TO 21N71W. SCATTERED SHOWERS ARE WITHIN 60 NM OF THE FRONT. A SECOND RIDGE AXIS COVERS THE AREA E OF THE ABOVE FRONT ANCHORED BY A 1032 MB HIGH N OF THE AZORES. THE CENTRAL ATLC COLD FRONT WILL BECOME STATIONARY AND DISSIPATE THROUGH TUE. W ATLC HIGH PRESSURE WILL DRIFT SOUTHWARD BETWEEN 70W AND 75W MON THROUGH WED. A COLD FRONT WILL SWEEP ACROSS FAR N/CENTRAL ATLC MON NIGHT THROUGH TUE NIGHT. A WEAK COLD FRONT MOVING INTO W ATLC WED NIGHT WILL REACH FROM 32N75W TO N FLORIDA THU. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW