000 AXNT20 KNHC 211758 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1745 UTC. ...SPECIAL FEATURE... THE GALE WARNING METEO FRANCE ISSUED EARLIER THIS MORNING FOR ZONE 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 100-120 NM BETWEEN STRONG HIGH PRES OF 1036 MB WELL N OF THE DISCUSSION AREA AT 43W17W...AND LOW PRES TO ITS E AND SE OVER NORTHERN AFRICA REMAIN IN PLACE. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLANTIC NEAR 10N14W TO 6N21W WHERE IT TRANSITIONS TO THE ITCZ ITCZ AND CONTINUES TO 2N40W TO 05N30W AND TO THE COAST OF S AMERICA NEAR 01N50W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS S OF THE MONSOON TROUGH FROM 2N-10N BETWEEN 9W- 20W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE SEEN WITHIN 120 NM NW OF THE MONSOON TROUGH BETWEEN 16W-19W. SCATTERED MODERATE CONVECTION IS WITHIN 180 NM S OF THE MONSOON TROUGH BETWEEN 16W-18W...AND WITHIN 60 NM OF THE ITCZ BETWEEN 22W-28W. ...DISCUSSION... GULF OF MEXICO... THE TAIL END OF AN UPPER TROUGH LOCATED OVER THE EASTERN U.S. EXTENDS SW TO THE NE GULF...AND SW TO NEAR 26N88W. BROAD UPPER RIDGING HAS MOVED EASTWARD TO THE WESTERN PART OF THE GULF. UPPER NORTHWESTERLY FLOW BETWEEN BOTH OF THESE FEATURES IS PRESENT E OF 93W. THE DAILY NOCTURNAL TROUGH THAT FORMS NEAR THE NW YUCATAN PENINSULA HAS MIGRATED WESTWARD TO ALONG 93W S OF 22N. SATELLITE IMAGERY SHOWS A RELATIVELY CLOUD FREE GULF...WITH ONLY MINIMAL SCATTERED LOW CLOUDS THROUGHOUT N OF 22N. THE EXCEPTION IS ACROSS EASTERN TEXAS...AND COASTAL WATERS. BOTH DOPPLER RADAR AND SATELLITE IMAGERY SHOW SCATTERED STRONG CONVECTION IN MCS TYPE FASHION PUSHING SSE ACROSS SOUTHERN TEXAS AND THE COASTAL WATERS THERE...WHILE SCATTERED SHOWERS AND ISOLATED TSTMS ARE DEVELOPING ELSEWHERE OVER EASTERN TEXAS AND ITS COASTAL WATERS. THIS IS PRIMARILY DUE TO THE FOCUS OF A SURFACE COLD FRONT ACROSS EASTERN TEXAS COMPILED WITH MOIST AND UNSTABLE AIR MASS IN PLACE AND POSSIBLE UPPER LEVEL DISTURBANCES RIDING SE ACROSS THE UPPER RIDGING. AS OF 15 UTC...A 1018 MB HIGH CENTER AT 27N87W IS KEEPING AN ANTICYCLONIC FLOW CONSISTING OF 5-10 KT WINDS E OF ABOUT 90W...SE FLOW OF 10-15 KT IS TO THE W OF 90W...EXCEPT FOR WINDS E-SE IN DIRECTION S OF 22N W OF 90W. THE 1017 MB HIGH IS FORECAST TO DISSIPATE IN ABOUT 24 HRS...WHILE 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... A 1009 MB LOW IS CENTERED OVER NW COLOMBIA NEAR 10N75W. THE SURFACE ANALYSIS HAS A RATHER WEAK PRES GRADIENT THROUGHOUT ...WITH THE EXCEPTION OF THE S CENTRAL AND SW PORTIONS WHERE THE STRONGER THERE SUPPORTS NE-E WINDS OF 15-25 KT TRADE WINDS WITH THE HIGHEST OF THESE ALONG THE NORTHERN COAST OF COLOMBIA AND WEAKEST WINDS ALONG THE S COAST OF CUBA. WATER VAPOR IMAGERY INDICATES BROAD UPPER RIDGING PERSISTING ACROSS THE CARIBBEAN E OF CENTRAL AMERICA...WHILE W OF THERE AN UPPER TROUGH EXTENDS FROM THE WESTERN TIP OF CUBA SW TO GUATEMALA...AND CONTINUES TO THE EASTERN PACIFIC. UPPER LEVEL DIVERGENCE SE OF THE UPPER TROUGH IS AIDING CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION SEEN SW OF A LINE FROM NE NICARGAGUA TO 10N76W. ELSEWHERE...ONLY ISOLATED SHOWERS AND TSTMS ARE NOTED ELSEWHERE PRIMARILY E OF 81W...EXCEPT FOR SCATTERED SHOWERS AND ISOLATED TSTMS ENHANCED BY A SMALL UPPER DISTURBANCE IN THE SW FLOW AHEAD OF THE UPPER TROUGH NOTED N OF 18N E OF JAMAICA INCLUDING THE WINDWARD PASSAGE. WATER VAPOR IMAGERY SHOWS MODERATE TO STRONG STRONG SUBSIDENCE FILTERING EASTWARD ACROSS THE NW CARIBBEAN ALLOWING FOR GENERALLY CLOUD FREE SKIES THERE. ONLY SMALL LINES OF LOW CLOUDS WITH POSSIBLE ISOLATED SHOWERS ARE SEEN MOVING WESTWARD OVER THAT PART OF THE SEA. EXPECT THE SCATTERED SHOWERS AND ISOLATED TSTMS N OF 18N TO GRADUALLY SLIDE EASTWARD OVER THE NEXT 24-48 HRS. ELSWHERE...LITTLE CHANGE IS FORECAST OVER THE NEXT 24-48 HRS. ...HISPANIOLA... SCATTERED SHOWERS AND ISOLATED TSTMS AS DESCRIBED UNDER THE CARIBBEAN SECTION ARE APPROACHING HAITI FROM THE WINDWARD PASSAGE. SATELLITE IMAGERY SHOWS SCATTERED SHOWERS AND TSTMS DEVELOPING OVER THE INTERIOR PORTIONS OF THE ISLAND WHERE OROGRAPHIC LIFTING AS AFTERNOON DAYTIME HEATING GETS UNDER WAY. IN ADDITION...PLENTY OF AVAILABLE MOISTURE AND INSTABILITY THERE IS FURTHER FUELED BY ENERGY FROM THE APPROACHING UPPER TROUGH DESCRIBED ABOVE. THIS SCENARIO WILL LINGER INTO THE NEXT 24-36 HRS. ACTIVITY MAY DECREASE IN COVERAGE SUN AS UPPER AIR BECOMES MORE STABLE. ATLANTIC OCEAN... AN UPPER LEVEL LOW IS CENTERED OVER THE W ATLANTIC NEAR 30N67W. ANOTHER UPPER LEVEL LOW IS CENTERED OVER THE CENTRAL ATLANTIC N OF OF THE AREA NEAR 35N44W...AND IS LIFTING NE. AN ASSOCIATED SURFACE TROUGH EXTENDS FROM THE SURFACE LOW AT 36N50W 1013 S TO 31N48W. A 1019 MB HIGH IS OVER THE W ATLANTIC NEAR 28N59W WITH A RIDGE SW TO THE CENTRAL BAHAMAS. A SURFACE TROUGH...REMNANTS OF AN OLD FRONTAL BOUNDARY...EXTENDS FROM NEAR 31N46W SW TO 24N55W TO JUST NE OF PUERTO RICO AS OF 12 UTC THIS MORNING. SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN 60 NM OF THE TROUGH E OF 61W...AND ISOLATED SHOWERS ARE WITHIN 90 NM OF THE TROUGH W OF 61W. A 1036 MB HIGH IS WELL NE OF THE AREA NEAR 43N17W WITH ASSOCIATED RIDGING STRETCHING FROM IT SW TO 22N45W. HIGH PRES IS PRESENT ACROSS THE EASTERN ATLANTIC N OF 18N E OF 43W. A THIRD UPPER LEVEL LOW IS CENTERED OVER THE E ATLANTIC NEAR 26N23W. THE UPPER LOW NEAR 30N67W IS FORECAST TO MOVE ESE OVER THE NEXT 48 HRS WHILE WEAKENING TO A TROUGH AS THE UPPER RIDGING OVER THE GULF OF MEXICO SLIDES EASTWARD TO THE WESTERN ATLANTIC AND BAHAMAS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ AGUIRRE