000 AXNT20 KNHC 231000 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT TUE SEP 23 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1000 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS 140 NM W OF THE CAPE VERDE ISLANDS WITH AXIS EXTENDING FROM 22N26W TO A 1011 MB LOW NEAR 17N28W TO 12N28W MOVING W AT 10-15 KT. AN AREA OF WARM DRY AIR W OF THE LOW CENTER IS DEPICTED IN THE SSMI TPW AND THE METEOSAT SAL IMAGERY. SAHARAN DUST IS ALSO IN THE WAVE ENVIRONMENT...RESULTING IN THE LACK OF CONVECTION OVER MOST OF THE AREA COVERED BY THIS WAVE. ONLY A FEW SHOWERS ARE NOTICED ALONG 19N BETWEEN 25W-28W. A TROPICAL WAVE IS ON THE CENTRAL ATLANTIC WITH AXIS EXTENDING FROM 18N44W TO 07N46W...MOVING W AT 20 KT. DRY AND STABLE SAHARAN AIR IS ALSO IN THE ENVIRONMENT OF THIS WAVE...LIMITING THE CONVECTION TO THE SOUTHERN PORTION OF THE WAVE AXIS FROM 11N- 13N BETWEEN 41W-48W. A TROPICAL WAVE IS MOVING ACROSS THE MONA PASSAGE IN THE CARIBBEAN WITH AXIS EXTENDING FROM 21N67W TO 11N68W...MOVING W AT 10 KT. DEEP LAYER MODERATE MOISTURE ACCOMPANIES THIS WAVE... WHICH ALONG LOW-LEVEL MOISTURE CONVERGENCE AND UPPER-LEVEL DIFFLUENCE HELPS TO GENERATE SCATTERED MODERATE CONVECTION MAINLY ACROSS THE NORTHERN PORTION OF THE WAVE AXIS N OF 17N BETWEEN 64W-70W. A TROPICAL WAVE IS ACROSS WESTERN CUBA WITH AXIS EXTENDING FROM 23N84W TO NORTHERN COSTA RICA NEAR 10N85W. THIS WAVE IS MOVING W AT 10 KT. DRY AIR SUBSIDENCE FROM ALOFT IS LIMITING THE DEVELOPMENT OF CONVECTION ACROSS THE WAVE. SCATTERED MODERATE CONVECTION CONTINUES IN THE VICINITY OF THE WAVE AXIS...WHICH IS BEING ENHANCED BY AN UPPER-LEVEL TROUGH LOCATED ACROSS THE EASTERN GULF AND EXTENDING TO THE YUCATAN PENINSULA. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 14N22W TO A 1011 MB LOW NEAR 17N28W TO 12N30W TO 08N49W. ASIDE FROM CONVECTION OCCURRING WITH THE TROPICAL WAVES...ISOLATED CONVECTION IS ALONG 12N BETWEEN 32W-38W. ...DISCUSSION... GULF OF MEXICO... A UPPER-LEVEL TROUGH ALONG THE EASTERN US EXTENDS ITS BASE ACROSS THE EASTERN GULF AND ACROSS THE FLORIDA PENINSULA. THIS TROUGH SUPPORTS A PAIR OF FRONTAL BOUNDARIES...A STATIONARY FRONT ANALYZED ACROSS NORTHERN FLORIDA CONNECTED TO A 1008 MB LOW NEAR 28N84W TO 26N91W...AND A COLD FRONT ACROSS THE SE US EXTENDING ACROSS THE N GULF WATERS. THE COLD FRONT IS FORECAST TO MERGE WITH THE STATIONARY ONE SOMETIME TODAY. SE OF THE UPPER- LEVEL TROUGH...RIDGING IS GENERATING DIFFLUENT FLOW WHICH ALONG THE ABUNDANT LOW-LEVEL MOISTURE ADVECTED FROM THE CARIBBEAN SUPPORTS NUMEROUS MODERATE TO STRONG CONVECTION S OF THE STATIONARY FRONT S OF 25N...E OF 87W. OVER THE NEXT 24-48 HOURS...THE FRONT WILL DISSIPATE WHILE MOVING ACROSS CENTRAL FLORIDA. A TROPICAL WAVE IS EXPECTED TO MOVE INTO THE BAY OF CAMPECHE BY THURSDAY. CARIBBEAN SEA... TWO TROPICAL WAVES ARE IMPACTING THE CARIBBEAN...FOR MORE INFORMATION ABOUT THESE REFER TO THE SECTION ABOVE. AN UPPER- LEVEL LOW WITH CENTER NEAR 18N82W IS ENHANCING SCATTERED MODERATE CONVECTION FROM 18N-22N BETWEEN 78W-82W. LOW-LEVEL MOISTURE CONVERGENCE IS ENHANCING SCATTERED MODERATE TO STRONG CONVECTION ACROSS THE WESTERN CARIBBEAN MAINLY W OF CUBA. SCATTERED MODERATE CONVECTION PREVAILS ACROSS CENTRAL AMERICA AND THE SOUTHERN CARIBBEAN WATERS S OF 13N ENHANCED BY THE MONSOON TROUGH AXIS THAT EXTENDS FROM COLOMBIA TO COSTA RICA. OVER THE NEXT 24-48 HOURS...THE TROPICAL WAVE ON THE EASTERN CARIBBEAN IS EXPECTED TO MOVE ACROSS HISPANIOLA AND THE CENTRAL CARIBBEAN ENHANCING CONVECTION. ...HISPANIOLA... SCATTERED SHOWERS AND THUNDERSTORMS ARE NOTICED ACROSS THE NE HISPANIOLA AS THE TROPICAL WAVE APPROACHES. AN INCREASE IN CONVECTIVE ACTIVITY IS EXPECTED OVER THE NEXT 24 HOURS AS THE TROPICAL WAVE MOVES ACROSS THE ISLAND AND ADJACENT WATERS. ATLANTIC OCEAN... AN UPPER-LEVEL TROUGH IS OVER THE EASTERN US THAT SUPPORTS A STATIONARY FRONT ANALYZED FROM 30N78W TO 30N81W AND THEN ACROSS NORTHERN FLORIDA INTO THE EASTERN GULF WATERS. AN UPPER-LEVEL HIGH CONTINUES ACROSS THE WESTERN ATLANTIC WITH CENTER NEAR 31N64W NEAR THE END OF A COLD FRONT. THESE SYSTEMS ARE KEEPING A DIFFLUENT FLOW BETWEEN THEM THAT COMBINED WITH LOW-LEVEL MOISTURE CONVERGENCE ARE GENERATING NUMEROUS MODERATE TO STRONG CONVECTION ACROSS THE BAHAMAS...SOUTH FLORIDA ATLANTIC WATERS...THE FLORIDA KEYS...AND NW CUBA FROM 23N-31N BETWEEN 75W- 83W. THERE IS ALSO ISOLATED CONVECTION NEAR THE CENTER OF THE UPPER LEVEL HIGH PREVIOUSLY MENTIONED ALONG THE FRONTAL BOUNDARY NEXT TO IT FROM 34N-42N BETWEEN 55W-66W. TO THE E...AN UPPER- LEVEL LOW CENTERED NEAR 24N55W IS SUPPORTING ISOLATED MODERATE CONVECTION ALONG 24N BETWEEN 55W-57W. A SURFACE TROUGH WAS ANALYZED ALONG 50W BETWEEN 25N-31N...WHICH HAS ISOLATED MODERATE CONVECTION AT ABOUT 150 NM E AND W OF THE BOUNDARY. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ ERA