000 AXNT20 KNHC 220006 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU MAY 21 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 FEATURE... GALE WARNING BY METEO FRANCE FOR THE ZONE OF AGADIR ALONG THE COAST OF MOROCCO REMAINS IN EFFECT. BEAFORT 7-8 OR 32 TO 46 KT WINDS ARE FORECAST FOR THIS ZONE AS VERY TIGHT PRES GRADIENT WITH ISOBARIC SPACING OF ONLY 60-100 NM BETWEEN STRONG HIGH PRES OF 1035 MB WELL N OF THE DISCUSSION AREA AT 43W17W...AND LOW PRES TO ITS E AND SE OVER NORTHERN AFRICA. ...TROPICAL WAVES... A TROPICAL WAVE CAME OFF THE AFRICAN COAST EARLIER TODAY EMBEDDED IN ABUNDANT LOW LEVEL MOISTURE AS INDICATED BY THE SSMI TPW IMAGERY. SATELLITE DERIVED WINDS INDICATE A DIFFLUENT ENVIRONMENT ALOFT WITHIN THE WAVE ENVIRONMENT...WHICH IS SUPPORTING SCATTERED MODERATE CONVECTION WITHIN 300 NM EITHER SIDE OF THE WAVE AXIS LOCATED FROM 02N TO 10N NEAR 18W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLANTIC NEAR 10N14W TO 08N16W. IT THEN RESUMES W OF A TROPICAL WAVE FROM 07N19W TO 06N26W WHERE THE ITCZ BEGINS AND CONTINUES TO 04N38W TO THE NORTHERN COAST OF BRAZIL NEAR 02N51W. SCATTERED TO ISOLATED MODERATE CONVECTION IS WITHIN 60 NM EITHER SIDE OF THE ITCZ BETWEEN 26W AND 40W. ...DISCUSSION... GULF OF MEXICO... A MIDDLE TO UPPER TROUGH LOCATED OVER THE EASTERN U.S. EXTENDS S TO A BASE OVER THE SE GULF. THIS TROUGH IS SUPPORTING A COLD FRONT THAT EXTENDS FROM GEORGIA NEAR 30N84W...ACROSS THE FLORIDA PANHANDLE...SOUTHERN ALABAMA AND MISSISSIPPI TO 29N92W SW TO 27N97W. LOW-LEVEL MOISTURE CONVERGENCE ALONG THE N-NW BASIN ALONG WITH DIFFLUENCE GENERATED BY A MIDDLE LEVEL RIDGE OVER THE WESTERN GULF SUPPORT SCATTERED MODERATE CONVECTION AND TSTMS N OF 22N W OF 93W...SE LOUISIANA...SOUTHERN MISSISSIPPI AND ALABAMA. WITH NO SUPPORT ALOFT...A 1017 MB HIGH CENTER CONTINUES TO WEAKEN TONIGHT. ELSEWHERE...SATELLITE IMAGERY SHOWS A RELATIVELY CLOUD FREE GULF. ANTICYCLONIC FLOW CONSISTING OF 5-10 KT WINDS DOMINATES ACROSS THE BASIN. THE AFOREMENTIONED COLD FRONT SHOULD EXTEND FROM NEAR FROM NEAR W CENTRAL FLORIDA NW TO SE LOUISIANA WHERE IT BECOMES STATIONARY WSW FROM THERE TO INLAND VICINITY CENTRAL TEXAS. SIMILAR UNSETTLED WEATHER SHOULD CONTINUE IN ASSOCIATION WITH THE EARLIER MENTIONED FRONT...WITH SIMILAR WEATHER EXPECTED TO DEVELOP ALONG AND INLAND THE N CENTRAL GULF FRI INTO SAT FURTHER AIDED BY AN UPPER LEVEL DISTURBANCE PASSING ACROSS THOSE AREAS. OTHERWISE...THE UPPER RIDGE IS FORECAST TO COVER JUST ABOUT THE ENTIRE GULF BY SAT. CARIBBEAN SEA... THE CENTRAL AND PORTIONS OF THE 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 NICARAGUA...COSTA RICA...PANAMA...HISPANIOLA AND ADJACENT WATERS. SIMILAR CONVECTION IS OBSERVED OVER CENTRAL AND EASTERN CUBA BEING ENHANCED BY A MIDDLE TO UPPER LEVEL TROUGH ACROSS THE NW CARIBBEAN. HOWEVER...OVER THE NW BASIN DRY AND STABLE AIR IS INDICATED BY BOTH WATER VAPOR AND SSMI TOTAL PRECIPITABLE WATER IMAGERY...WHICH IS SUPPORTING FAIR WEATHER. 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 WITH SEAS LESS THAN 8 FT. THESE WINDS WILL CONTINUE TO PULSE NEAR THE COAST OF COLOMBIA THE NEXT TWO DAYS BEFORE DIMINISHING AS THE PRES GRADIENT CONTINUES TO RELAX. OTHERWISE GENTLE TRADES AND 4-6 FT SEAS PREVAIL S OF 17N...WITH GENTLE TRADES AND 2-4 FT SEAS N OF 17N. EXPECT SCATTERED SHOWERS AND ISOLATED TSTMS N OF 18N TO GRADUALLY SLIDE EASTWARD OVER THE NEXT 24-48 HRS. ELSEWHERE...LITTLE CHANGE IS FORECAST THE NEXT TWO DAYS. ...HISPANIOLA... DEEP LAYER MOISTURE OVER THE REGION ALONG WITH A MIDDLE LEVEL DIVERGENT ENVIRONMENT CONTINUE TO SUPPORT SCATTERED MODERATE CONVECTION AND TSTMS ACROSS THE ISLAND EXTENDING TO COASTAL WATERS. THIS SCENARIO WILL LINGER INTO THE NEXT 24-36 HRS. ACTIVITY MAY DECREASE IN COVERAGE SUN AS UPPER AIR BECOMES MORE STABLE. ATLANTIC OCEAN... A SURFACE TROUGH...REMNANTS OF AN OLD FRONTAL BOUNDARY...EXTENDS FROM NEAR 31N47W SW TO 26N50W TO 21N59W WITH ISOLATED SHOWERS WITHIN 160 NM AHEAD OF ITS AXIS. WEST OF THE TROUGH...A 1020 MB HIGH IS ANCHORED NEAR 28N54W...WHICH IS FORECAST TO WEAKEN TONIGHT. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS EXTENDS WITHIN 75 NM OFF THE NORTHERN COASTS OF EASTERN CUBA AND HISPANIOLA AS WELL AS N OF THE MONA PASSAGE. A 1035 MB HIGH IS WELL NE OF THE AREA NEAR 43N17W WITH ASSOCIATED RIDGING STRETCHING FROM IT SW TO 20N43W. HIGH PRES IS PRESENT ACROSS THE EASTERN ATLANTIC N OF 17N E OF 47W. A COLD FRONT EXTENDING ACROSS THE SE CONUS IS FORECAST TO MOVE INTO SW N ATLC WATERS BY FRIDAY MORNING...DISSIPATING SUNDAY MORNING. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR