000 AXNT20 KNHC 201758 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED APR 20 2016 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 FEATURES... ATLANTIC GALE WARNING...GALE FORCE WINDS ARE OCCURRING OVER THE CENTRAL ATLC FROM 25N TO 29N WITHIN 210 NM E OF A FRONT THAT EXTENDS THROUGH 32N36W TO 25N46W AND BECOMES STATIONARY TO 20N55W. THESE WINDS ARE FORECAST TO CONTINUE THROUGH 1800 UTC THIS AFTERNOON AT WHICH TIME THE FRONT WILL BEGIN TO WEAKEN AND THE CULPRIT TIGHT PRESSURE GRADIENT BEGINS TO RELAX. PLEASE SEE HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... A WEAK TROUGH EXTENDS ACROSS WESTERN AFRICA TO THE COAST OF SIERRA LEONE AT 09N13W. THE ITCZ AXIS AS DEFINED IN SCATTEROMETER DATA...AND ON SATELLITE IMAGERY BEGINS FROM JUST SW OF 09N13W TO 05N17W TO 04N27W TO 03N32W TO 03N40W TO 02N46W TO S AMERICA NEAR 01N51W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM N OF THE AXIS BETWEEN 45W-49W...AND WITHIN 60 NM S OF THE AXIS BETWEEN 27W-29W. SIMILAR ACTIVITY IS N OF THE ITCZ WITHIN 30 NM OF LINE 05N46W TO 05N49W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 30 NM OF LINE FROM 06N52W TO 06N55W. ...DISCUSSION... GULF OF MEXICO... AN UPPER TROUGH EXTENDS FROM THE LOUISIANA/TEXAS BORDER ACROSS THE W GULF TO THE YUCATAN PENINSULA/YUCATAN CHANNEL. A SURFACE TROUGH IS THE SW GULF EXTENDING FROM 23N96W TO THE BAY OF CAMPECHE NEAR 19N95W. THE EARLIER SCATTERED SHOWERS AND ISOLATED TSTM ACTIVITY HAS BECOME ISOLATED DURING THE MORNING AND EARLY AFTERNOON. THE DIURNAL SURFACE TROUGH THAT WAS OVER THE YUCATAN PENINSULA LAST NIGHT...HAS MOVED OVER THE EASTERN BAY OF CAMPECHE THIS MORNING ALONG 92W S OF 21N. A RATHER VIGOROUS MID/UPPER LEVEL SHORTWAVE TROUGH IS SEEN ON WATER VAPOR IMAGERY MOVING ACROSS THE EASTERN GULF FROM SE LOUISIANA TO NEAR THE NW COAST OF CUBA. A SURFACE COLD FRONT IS MOVING ACROSS CENTRAL TEXAS...AND IS PRECEDED BY AN OUTFLOW BOUNDARY RACING SE ACROSS EASTERN TEXAS N OF CORPUS CHRISTI. SCATTERED SHOWERS AND TSTMS WITH THE BOUNDARY SHOULD REACH THE TEXAS COASTAL WATERS EARLY THIS AFTERNOON WHILE WEAKENING OTHERWISE...INSTABILITY AHEAD OF THE TROUGH IS ENOUGH TO ALLOW FOR SCATTERED SHOWERS AND ISOLATED WEAK TSTMS TO EXIST N OF 23N E OF 88W. IN ADDITION...A SURFACE REFLECTION OF THE TROUGH IS FROM APALACHEE BAY TO 27N86W. ISOLATED SHOWERS AND TSTMS HAVE MOVED TO THE E OF THIS TROUGH...AND ARE WEAKENING. A WEAKENING SURFACE RIDGE REMAINS OVER THE EASTERN GULF AND WESTERN ATLC ANCHORED BY A 1021 MB HIGH CENTER E OF THE NE FLORIDA. SURFACE RIDGING WILL PERSIST THROUGH THU...THEN THE HIGH WILL MOVE EASTWARD ALLOWING FOR A WEAK COLD FRONT TO MOVE E THROUGH THE N AND NE GULF FRI AND SAT WITH HIGH PRESSURE FOLLOWING IN THE WAKE OF THE FRONT. CARIBBEAN SEA... AN UPPER RIDGE OVER S AMERICA AND THE WESTERN TROPICAL ATLC IS SUPPLYING THE UPPER ATMOSPHERE OVER THE BASIN WITH SW TO W FLOW THIS AFTERNOON. THE TAIL-END OF THE CENTRAL ATLC COLD FRONT EXTENDS AS A DISSIPATING STATIONARY FRONT SW TO NEAR GUADELOUPE IN THE LEEWARD ISLANDS. LINGERING LOW AND MID LEVEL MOISTURE IN COMBINATION WITH UPPER JET DYNAMICS CONTINUE TO RESULT IN SCATTERED SHOWERS AND ISOLATED TSTMS ARE OBSERVED BETWEEN 72W AND 65W...AND ALSO N OF 15N E OF 65W TO THE AREA OF THE LEEWARD ISLANDS. CURRENTLY...THE NWS SAN JUAN DOPPLER RADAR IS SHOWING SCATTERED SHOWERS STAYING TO THE S AND SW OF THE ISLAND... HOWEVER SCATTERED TO BROKEN LOW CLOUDS ARE FORMING OVER THE INTERIOR PORTION OF THE ISLANDS WITH DAYTIME HEATING UNDERWAY. SOME OF THESE CLOUDS COULD SOON LEAD TO THE DEVELOPMENT OF SCATTERED SHOWERS AND TSTMS. THE SAME APPLIES FOR HISPANIOLA WHERE PRECIPITABLE TYPE CLOUDS ARE NOTED ON SATELLITE IMAGERY. THE SURFACE RIDGE OVER THE EASTERN GULF OF MEXICO AND THE WESTERN ATLC EXTENDS S TO OVER CUBA AND THE FAR NW CARIBBEAN. MODERATE TO FRESH TRADE WINDS WILL PERSIST ACROSS THE CARIBBEAN THROUGH THU NIGHT. NE WINDS ARE EXPECTED TO PULSE FRESH TO STRONG EACH NIGHT S OF HISPANIOLA AND INTO THE WINDWARD PASSAGE THROUGH THU NIGHT. W ATLC SURFACE HIGH PRES WILL SHIFT EASTWARD OVER BERMUDA FRI... THEN BECOME CENTERED NE OF THE AREA ON SAT DIMINISHING TRADE WINDS ACROSS MUCH OF THE CARIBBEAN. HISPANIOLA... WITH DAYTIME HEATING UNDERWAY SCATTERED TO BROKEN CUMULUS CLOUDS ARE DEVELOPING OVER THE INTERIOR OF THE ISLAND. THE EFFECTS OF OROGRAPHIC LIFTING SHOULD LEAD TO SOME OF THESE DEVELOPING INTO SCATTERED SHOWERS AND TSTMS IN THE AFTERNOON. THIS PATTERN IS EXPECTED TO REPEAT ITSELF ON THU. ON FRI...IT IS POSSIBLE THAT AN INCREASE OF LOW-LEVEL MOISTURE FROM THE S MAY AID IN THE DEVELOPMENT OF SCATTERED SHOWER/TSTM ACTIVITY. ATLANTIC OCEAN... A WEAKENING SURFACE RIDGE COVERS THE W ATLC W OF 65W TO OVER CUBA AND THE EASTERN GULF OF MEXICO ANCHORED BY A 1021 MB HIGH CENTER OFF THE NE FLORIDA COAST NEAR 30N78W. BROAD UPPER TROUGH COVERS THE W AND CENTRAL ATLC WITH AN AXIS EXTENDING THROUGH 32N38W SW TO 23N52W TO 21N64W. THE TROUGH SUPPORTS A COLD FRONT THAT EXTENDS FROM A LOW PRES CENTER N OF THE AREA SW THROUGH 32N36W TO 26N46W WHERE IT BECOMES STATIONARY TO 20N54W...AND DISSIPATING FROM THERE SW TO THE LEEWARD ISLANDS. A RE-ENFORCING SURGE IN THE FORM OF A SURFACE TROUGH TRAILS THE FRONT ALONG A POSITION FROM NEAR 32N46W SW TO 28N47W AND TO 23N54W. A BROAD UPPER RIDGE COVERS THE REMAINDER OF THE ATLC E OF THE UPPER TROUGH. A STRONG JET STREAM BRANCH EXTENDS IN BETWEEN BOTH OF THESE FEATURES FROM NEAR 20N62W NEWD TO 23N49W TO NE OF THE AREA AT 32N34W. RIPPLES OF SHORTWAVE ENERGY RIDING ALONG THE JET IN COMBINATION WITH DEEP MOISTURE WITHIN 200-500 NM SE OF THE FRONT ARE LEADING TO WAVES OF SCATTERED SHOWERS AND ISOLATED TSTMS UNDERNEATH THESE CLOUDS TO THE SE OF THE FRONT N OF 19N. SE OF THE FRONT S OF 19N...THE ACTIVITY HAS BECOME ISOLATED IN COVERAGE. A SURFACE RIDGE COVERS THE REMAINDER OF THE ATLC ANCHORED BY A 1021 MB HIGH NEAR 28N20W. THE AFOREMENTIONED COLD FRONT WILL MOVE SLOWLY EASTWARD THROUGH THIS EVENING WHILE WEAKENING TO A STATIONARY FRONT. THE STATIONARY FRONT IS FORECAST TO GRADUALLY DISSIPATE THROUGH THU. ANOTHER COLD FRONT WILL QUICKLY SWEEP SE ACROSS THE NE WATERS ON WED. HIGH PRESSURE WILL BUILD SE ACROSS THE WESTERN ATLC IN THE WAKE OF THE FRONTS THEN WEAKEN AS IT SHIFTS E ACROSS BERMUDA FRI AND SAT. A WEAK COLD FRONT IS FORECAST TO MOVE OFF THE SE U.S. COAST EARLY ON SAT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ AGUIRRE