000 AXNT20 KNHC 240004 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU APR 23 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 07N12W TO 04N17W WHERE THE ITCZ BEGINS AND CONTINUES TO 01S28W JUST E OF A SURFACE TROUGH ALONG 30W. THE ITCZ RESUMES W OF THE SURFACE TROUGH NEAR 02S32W AND CONTINUES TO THE NORTHERN COAST OF BRAZIL NEAR 02S44W. SCATTERED TO ISOLATED MODERATE CONVECTION IS FROM 07S TO 02N W OF 24W. SIMILAR CONVECTION IS FROM THE EQUATOR TO 05N W OF 45W. ...DISCUSSION... GULF OF MEXICO... A SHORTWAVE UPPER TROUGH SUPPORTS A 1009 MB LOW NEAR 37N47W FROM WHICH A COLD FRONT EXTENDS ACROSS THE CENTRAL ATLC TRANSITIONING TO A STATIONARY FRONT THAT STARTS TO DISSIPATE N OF THE SOUTHERN BAHAMAS. THE DISSIPATING STATIONARY FRONT THEN EXTENDS NW ACROSS THE NORTHERN BAHAMAS TO SOUTH OF LAKE OKEECHOBEE THE ACROSS THE NE GULF OF MEXICO ALONG 26N82W TO 29N86W TO SE LOUISIANA NEAR 29N91W. A MIDDLE TO UPPER LEVEL TROUGH WITH BASE OVER THE SW N ATLC ALONG WITH A RIDGE ANCHORED OVER THE SOUTHERN GULF IS GENERATING A SLIGHT DIFFLUENT ENVIRONMENT OVER THE NE GULF. WIND FLOW AROUND THE RIDGE ALSO ADVECTS MOISTURE FROM THE EPAC WATERS TO THE NORTHERN GULF WHERE SSMI TPW IMAGERY CONTINUE TO SHOW ABUNDANT MOISTURE. DEEP LAYER MOISTURE ENHANCES SCATTERED SHOWERS AND TSTMS WITHIN 100 NM S OF THE FRONT AND ISOLATED SHOWERS AND TSTMS N OF THE BOUNDARY...INCLUDING THE FLORIDA PENINSULA. FOG IS POSSIBLE FOR THE NW GULF N OF 27N AND ALONG COASTAL WATERS OF THE YUCATAN PENINSULA AS INDICATED BY GOES-13 MEDIUM TO HIGH IFR FOG PROBABILITIES. FAIR WEATHER IS ELSEWHERE. LIGHT VARIABLE WINDS UP TO 10 KT ARE ACROSS THE BASIN. THE DISSIPATING FRONT IS FORECAST TO WEAKEN INTO A SURFACE TROUGH LATE TONIGHT THAT IS EXPECTED TO DISSIPATE FRIDAY MORNING. LOW PRESSURE WILL DOMINATE ACROSS THE BASIN FOR THE NEXT THREE DAYS. CARIBBEAN SEA... NORTHERLY FLOW ASSOCIATED WITH A WEAK CENTER OF HIGH PRESSURE OVER THE SW N ATLC WATERS AND E-SE TRADES OVER THE NORTHERN CARIBBEAN WATERS IS GENERATING AN ELONGATED AREA OF LOW PRESSURE OVER CUBA...WHICH ALONG MIDDLE TO LOW LEVEL MOISTURE BEING ADVECTED FROM THE NORTHERN GULF OF MEXICO SUPPORT SCATTERED SHOWERS AND TSTMS OVER CENTRAL CUBA...EXTENDING TO ADJACENT WATERS. MIDDLE TO LOW LEVEL MOISTURE ASSOCIATED WITH THE FRONTAL BOUNDARY ACROSS THE SW N ATLC IS BEING ADVECTED TO HISPANIOLA...WHICH ALONG A DIFFLUENT ENVIRONMENT ALOFT SUPPORT CLOUDINESS ACROSS THE ISLAND. HOWEVER...SHOWERS ARE NOT EXPECTED AS DEEP LAYER DRY AIR DOMINATES ACROSS THE ISLAND. ISOLATED SHOWERS ARE POSSIBLE ACROSS THE WINDWARD PASSAGE. FAIR WEATHER PREVAILS ELSEWHERE. TRADES OF 15 KT DOMINATES ACROSS THE CARIBBEAN...INCREASING TO 20 TO 25 KT ALONG THE COAST OF COLOMBIA. NO SIGNIFICANT CHANGES ARE EXPECTED DURING THE NEXT TWO DAYS. HISPANIOLA... A MIDDLE TO UPPER LEVEL DIFFLUENT ENVIRONMENT IS OVER THE ISLAND...HOWEVER CURRENTLY DEEP LAYER DRY AIR IS PREVENTING THE DEVELOPMENT OF CONVECTION. DRY AIR IS FORECAST TO PREVAIL ACROSS THE ISLAND THROUGH THU NIGHT. MOISTURE AHEAD OF A FRONT TO MOVE N OF THE ISLAND WILL ENHANCE SHOWERS OVER HISPANIOLA FRIDAY MORNING. ATLANTIC OCEAN... A SHORTWAVE UPPER TROUGH SUPPORTS A 1009 MB LOW NEAR 37N47W FROM WHICH A COLD FRONT EXTENDS ACROSS THE CENTRAL ATLC ALONG 30N47W SW TO 27N57W WHERE IT TRANSITIONS TO A STATIONARY FRONT SW TO 25N68W THEN STARTS TO WEAKEN TO THE NORTHERN BAHAMAS NEAR 26N78W INTO SOUTHERN FLORIDA NW ACROSS THE NE GULF TO SOUTHERN LOUISIANA. SCATTERED MODERATE CONVECTION IS N OF 25N BETWEEN 45W AND 64W. SIMILAR CONVECTION ALONG WITH TSTMS ARE S OF THE BOUNDARY TO ANDROS ISLAND W OF 76W. SURFACE RIDGING AND FAIR WEATHER PREVAILS ELSEWHERE. A NEW COLD FRONT ENTERS THE SW N ATLC FRIDAY MORNING ENHANCING SCATTERED TO ISOLATED SHOWERS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR