000 AXNT20 KNHC 210003 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED MAY 20 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. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLANTIC NEAR 11N15W TO 06N17W TO 05N23W WHERE THE ITCZ BEGINS AND CONTINUES TO 02N40W TO THE COAST OF NORTHERN BRAZIL NEAR 01N50W. SCATTERED TO ISOLATED MODERATE CONVECTION IS FROM 02N TO 09N E OF 22W. ISOLATED SHOWERS ARE WITHIN 120 NM EITHER SIDE OF THE ITCZ BETWEEN 25W AND 35W. ...DISCUSSION... GULF OF MEXICO... A WEAK SURFACE RIDGE DOMINATES THE CENTRAL AND EASTERN GULF WATERS BEING ANCHORED BY A 1017 MB HIGH NEAR 28N86W. FAIR WEATHER PREVAILS UNDER UPPER LEVEL RIDGING AND DRY AIR SUBSIDENCE W OF 90W AND SURFACE DRY AIR AND RIDGING E OF 90W. LIGHT TO MODERATE ANTICYCLONIC FLOW CONTINUE TO DOMINATE THE BASIN...EXCEPT IN THE NE GULF NEAR THE HIGH CENTER WHERE LIGHT AND VARIABLE AIR PERSISTS. THERMAL TROUGHING DEVELOPED OVER THE YUCATAN PENINSULA THIS EVENING...WHICH IS FORECAST TO MOVE OFFSHORE INTO THE SW GULF INTO THU MORNING...AND YET AGAIN FRI EVENING INTO SAT MORNING. AS A RESULT WINDS WILL INCREASE TO FRESH NEAR THE NW YUCATAN PENINSULA WITH SEAS BUILDING TO UP TO 7 FT AS A RESULT. SURFACE RIDGING AND FAIR WEATHER WILL DOMINATE ELSEWHERE THE NEXT TWO DAYS. CARIBBEAN SEA... THE CENTRAL AND EASTERN CARIBBEAN CONTINUE TO MOISTEN DUE TO MIDDLE TO UPPER LEVEL SOUTHWESTERLY TO WESTERLY FLOW ADVECTION OF TROPICAL MOISTURE FROM THE PACIFIC OCEAN AND NORTHERN SOUTH AMERICA...AND ADVECTION OF ATLANTIC LOW LEVEL TROPICAL MOISTURE BY THE TRADES. DEEP LAYER MOISTURE COMBINED WITH A DIVERGENT ENVIRONMENT SUPPORT SCATTERED MODERATE CONVECTION AND TSTMS OVER COSTA RICA...PANAMA...HISPANIOLA AND ADJACENT WATERS. A MIDDLE TO UPPER LEVEL TROUGH IS ACROSS THE NW CARIBBEAN WITH DRY AND STABLE AIR INDICATED BY WATER VAPOR AND SSMI TOTAL PRECIPITABLE WATER IMAGERY. A LOCALIZED TIGHT PRES GRADIENT CONTINUES IN THE S CENTRAL CARIBBEAN BETWEEN LOW PRES OVER NW COLOMBIA AND ATLC RIDGING N-NE OF THE AREA. THIS IS SUPPORTING A MODERATE TO FRESH BREEZE NEAR THE NW COAST OF COLOMBIA AND SEAS UP TO 8 FT. THESE WINDS WILL CONTINUE TO PULSE NEAR THE COAST OF COLOMBIA THE NEXT TWO DAYS BEFORE DIMINISHING AS THE PRES GRADIENT RELAXES SLIGHTLY. OTHERWISE GENTLE TRADES AND 4-6 FT SEAS PREVAIL S OF 17N...WITH GENTLE TRADES AND 2-4 FT SEAS N OF 17N. SCATTERED TO ISOLATED SHOWERS ARE ACROSS PUERTO RICO BEING ENHANCED BY THE TAIL OF A SURFACE TROUGH. EXPECT SIMILAR WEATHER CONDITIONS THROUGH THE NEXT 48 HOURS. ...HISPANIOLA... DEEP LAYER MOISTURE OVER THE REGION ALONG WITH A MIDDLE LEVEL DIVERGENT ENVIRONMENT IS SUPPORTING SCATTERED MODERATE CONVECTION AND TSTMS ACROSS THE ISLAND EXTENDING TO N-NE COASTAL WATERS. SHOWERS ARE EXPECTED TO CONTINUE THROUGH SATURDAY NIGHT. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL ELONGATED LOW AND ASSOCIATED TROUGH BETWEEN 48W AND 51W SUPPORT A 1009 MB LOW NEAR 35N52W FROM WHICH A COLD FRONT EXTENDS TO 30N50W SW TO 25N57W WHERE IT TRANSITIONS TO A STATIONARY FRONT TO 25N65W TO 29N68W. OVER THE SW N ATLC...SURFACE RIDGING DOMINATES BEING ANCHORED BY A 1018 MB HIGH NEAR 27N69W. AHEAD OF THE FRONT...A SURFACE TROUGH EXTENDS FROM 27N49W TO 21N57W TO NE PUERTO RICO NEAR 18N66W. SCATTERED MODERATE CONVECTION IS WITHIN 100 NM N OF CUBA AND HISPANIOLA. ISOLATED SHOWERS ARE OFF THE NORTHERN COAST OF PUERTO RICO. AHEAD OF THE COLD FRONT...SIMILAR CONVECTION IS N OF 24N BETWEEN 40W AND 52W. SURFACE RIDGING AND FAIR WEATHER DOMINATE ELSEWHERE OVER THE CENTRAL AND EASTERN ATLC. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR