000 AXNT20 KNHC 262348 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI SEP 26 2014 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 2315 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS IN THE E CARIBBEAN ALONG 67W FROM 12N TO 22N CROSSING WESTERN PUERTO RICO. THE WAVE IS INTERACTING WITH AN UPPER-LEVEL LOW AND IS PRODUCING A LARGE AREA OF MODERATE CONVECTION PARTICULARLY S OF PUERTO RICO TO ABOUT 15N AND JUST NE OF THE LEEWARD ISLANDS COVERING THE REGION FROM 16N TO 20N BETWEEN 58W AND 63W. THE WAVE WILL CONTINUE TO MOVE WESTWARD... REACHING THE CENTRAL CARIBBEAN TONIGHT AND THE WESTERN CARIBBEAN SAT NIGHT. HOWEVER THE UPPER-LOW IS FORECAST TO REMAIN NEAR PUERTO RICO AND THE UK/US VIRGIN ISLANDS THROUGH THE WEEKEND KEEPING THE ATMOSPHERE VERY UNSTABLE WITH THE POTENTIAL OF MORE SHOWERS AND TSTMS. A TROPICAL WAVE IS OVER THE YUCATAN PENINSULA GENERATING SOME SHOWER AND TSTMS MAINLY ON THE EAST SIDE OF THE WAVE AXIS. THIS WAVE WILL MOVE ACROSS THE SW GULF OF MEXICO TONIGHT AND SAT. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS OVER AFRICA INTO THE TROPICAL ATLC NEAR 12N16W AND CONTINUES TO NEAR 13N37W. THE ITCZ EXTENDS FROM 12N45W TO JUST EAST OF TRINIDAD AND TOBAGO NEAR 10N60W. A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION IS ALONG THE COAST OF AFRICA FROM 11N TO 14N LIKELY ASSOCIATED WITH THE NEXT TROPICAL WAVE. NO SIGNIFICANT CONVECTION IS NOTED ELSEWHERE. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER TROUGH IS OVER THE CENTRAL PLAIN STATES FROM THE UPPER MISSISSIPPI VALLEY TO W TEXAS GIVING THE GULF W-SW FLOW ALOFT. UPPER DIFFLUENCE BETWEEN THIS TROUGH AND A RIDGE OVER THE NW CARIBBEAN IS HELPING TO INDUCE SCATTERED MODERATE CONVECTION ACROSS THE NORTHERN HALF OF THE GULF. THIS ACTIVITY IS FURTHER ENHANCED BY A WEAKENING STATIONARY FRONT THAT EXTENDS FROM THE TAMPA BAY AREA ACROSS THE CENTRAL GULF TO NEAR 25N94W AT 26/2100 UTC. A TROUGH EXTENDS FROM THIS POINT TO 22N95W TO 19N94W. THIS FRONTAL BOUNDARY COMBINED WITH DIURNAL HEATING IS HELPING TO GENERATE SHOWERS AND THUNDERSTORMS ACROSS PARTS OF THE FLORIDA PENINSULA AND COASTAL WATERS MORE CONCENTRATED OVER CENTRAL FLORIDA BASED ON THE MOSAIC DOPPLER RADAR FROM THE SE U.S.. NE WINDS OF 15-20 KT ARE NOTED OVER THE NW PART OF THE GULF BY AN EARLIER ASCAT PASS. THE SAME SCATTEROMETER PASS SHOWED VERY WELL THE WIND SHIFT ASSOCIATED WITH THE AFOREMENTIONED TROUGH. THE FRONT WILL DRIFT N AND DISSIPATE THROUGH TONIGHT. THE FRONTAL REMNANTS WILL MOVE W AS A TROUGH WITH WEAK LOW PRES FORMING ALONG IT OVER THE N CENTRAL GULF BY SUN NIGHT. CARIBBEAN SEA... AS PREVIOUSLY MENTIONED...AN UPPER-LEVEL RIDGE IS OVER THE NW CARIBBEAN. A DIFFLUENT PATTERN ALOFT ASSOCIATED WITH THIS SYSTEM IS SUPPORTING THE DEVELOPMENT OF SCATTERED SHOWERS AND TSTMS OVER THE YUCATAN PENINSULA AND WESTERN CUBA. AN UPPER-LEVEL LOW IS CENTERED OVER PUERTO RICO WITH A TROUGH EXTENDING FROM THE LOW CENTER TO THE SW CARIBBEAN. SOUTHWESTERLY FLOW AHEAD OF THIS TROUGH IS TRANSPORTING ABUNDANT TROPICAL MOISTURE FROM NORTHERN SOUTH AMERICA INTO THE EASTERN CARIBBEAN. A TROPICAL WAVE IS ALSO OVER PUERTO RICO. SEE TROPICAL WAVES SECTION FOR DETAILS. GENTLE TO MODERATE TRADES WILL CONTINUE TO PREVAIL ACROSS THE BASIN THROUGH THE WEEKEND AS HIGH PRES REMAINS WEAK N OF AREA. ...HISPANIOLA... SCATTERED SHOWERS AND TSTMS FLARED UP ACROSS THE ISLAND THIS AFTERNOON UNDER THE INFLUENCE OF AN UPPER-LEVEL LOW CURRENTLY CENTERED NEAR THE SW PART OF PUERTO RICO. THE ABUNDANCE OF MOISTURE ACCOMPANYING THE TROPICAL WAVE AND THE UPPER LOW OVER PUERTO RICO WILL CONTINUE TO SPREAD ACROSS HISPANIOLA DURING THE WEEKEND. AS A RESULT...EXPECT AN INCREASE IN SHOWER AND TSTM ACTIVITY. ATLANTIC OCEAN... A STATIONARY FRONT EXTENDS FROM 31N78W TO CENTRAL FLORIDA. THIS FRONT IS FORECAST TO LIFT NORTHWARD ALONG THE FLORIDA COAST AND GRADUALLY DISSIPATE THROUGH SAT. THE ATLANTIC HIGH PRES REMAINS WEAK ACROSS THE FORECAST AREA. SEVERAL WEAK LOW PRES AREAS ARE NOTED INSTEAD. ONE IS NEAR 28N45W WITH A CENTRAL PRES OF 1012 MB. A TROUGH EXTENDS FROM THE LOW CENTER TO NEAR 24N50W. THIS SYSTEM IS GENERATING SOME SHOWER ACTIVITY. THE MOST RECENT ASCAT PASS SHOWED FRESH TO STRONG WINDS ON THE NE QUADRANT OF THE LOW. ANOTHER SURFACE TROUGH IS ANALYZED ACROSS THE ATLANTIC AND STRETCHES FROM 29N30W TO A 1011 MB LOW PRES NEAR 17N76W FORECAST TO DISSIPATE IN ABOUT 24 HOURS. AN EARLIER SCATTEROMETER PASS CONFIRMED THE PRESENCE OF THESE TWO FEATURES. THE THIRD LOW PRES OF 1011 MB IS EMBEDDED WITHIN THE ITCZ NEAR 13N43W AND IS FORECAST TO REMAIN NEARLY STATIONARY DURING THE NEXT 24 HOURS. NONE OF THESE LOWS HAVE THE POTENTIAL OF TROPICAL CYCLONE DEVELOPMENT. IN FACT...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 5 DAYS ACCORDING WITH THE LATEST TROPICAL WEATHER OUTLOOK ISSUED BY THE NATIONAL HURRICANE CENTER. THE NORTHERN EXTENT OF THE TROPICAL WAVE NOW LOCATED OVER PUERTO RICO WILL MOVE ACROSS THE FAR SOUTHERN WATERS OF THE SW N ATLANTIC THROUGH SUN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GR