000 AXNT20 KNHC 080004 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN SEP 07 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 2345 UTC. ...SPECIAL FEATURES... A TROPICAL WAVE ASSOCIATED WITH A 1009 MB LOW IS OVER THE FAR EASTERN ATLC. ITS AXIS EXTENDS FROM 18N17W TO THE LOW CENTER NEAR 9N17W FORECAST TO MOVE WESTWARD AT 15 KT WITHIN THE NEXT 24 HOURS. THE WAVE IS ASSOCIATED WITH HIGH MOISTURE IN THE MIDDLE TO LOWER LEVELS AS DEPICTED IN SSMI TPW IMAGERY SHOW WITH PATCHES OF HIGH MOISTURE REACHING THE MIDDLE TO UPPER LEVELS OBSERVED IN WATER VAPOR IMAGERY. CYCLONIC RAINBANDS OF SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE FROM 5N-14N E OF 23W...BEING SUPPORTED BY THE AFOREMENTIONED MOISTURE AND UPPER- LEVEL DIFFLUENCE. THERE IS A MEDIUM CHANCE OF TROPICAL CYCLONE FORMATION ASSOCIATED WITH THIS SYSTEM WITHIN THE NEXT TWO DAYS. SEE LATEST NHC TROPICAL WEATHER OUTLOOK UNDER AWIPS/WMO HEADERS MIATWOAT/ABNT20 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... A TROPICAL WAVE IS ON THE CENTRAL ATLC WITH AXIS EXTENDING FROM 21N37W TO A 1012 MB LOW NEAR 15N36W TO 11N34W...MOVING WEST AT 10 KT. THIS WAVE IS BEING SUPPORTED BY AN INVERTED TROUGH IN THE MIDDLE TO UPPER LEVELS. HOWEVER...MOISTURE IN THE MIDDLE TO UPPER LEVELS HAS DECREASED DUE TO THE INTRUSION OF SAHARAN DRY AIR AND DUST IN ITS ENVIRONMENT. STRONG DEEP LAYER ENVIRONMENTAL SW WIND SHEAR IN THE VICINITY OF THE WAVE IS KEEPING THE REMAINING CONVECTION WELL-SEPARATED FROM THE LOW CENTER. A TROPICAL WAVE IS ON THE CENTRAL CARIBBEAN WITH AXIS EXTENDING FROM 20N71W TO 10N73W...MOVING W AT 20-25 KT. A BROAD MIDDLE- LEVEL INVERTED TROUGH IN THE CARIBBEAN SUPPORT THIS WAVE. DEEP LAYER MOISTURE IN THE NORTHERN CARIBBEAN ALONG WITH UPPER-LEVEL DIFFLUENCE ACROSS THE CENTRAL BASIN SUPPORT SCATTERED MODERATE CONVECTION AND TSTMS FROM 14N-22N BETWEEN 64W-73W. A TROPICAL WAVE IS MOVING ACROSS THE YUCATAN PENINSULA WITH AXIS EXTENDING FROM 22N87W TO 13N90W WITH A WESTWARD TRANSLATION SPEED OF 20-25 KT. A MIDDLE-LEVEL INVERTED TROUGH ON THE S-SW GULF OF MEXICO SUPPORT THE WAVE. DEEP LAYER MOISTURE ACROSS THE REGION ALONG WITH UPPER LEVEL DIFFLUENCE GENERATED BY AN ELONGATED RIDGE ANCHORED OVER NORTHERN CENTRAL AMERICA ENHANCE SCATTERED MODERATE CONVECTION AND TSTMS S OF 23N BETWEEN 84W-92W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 9N19W AND CONTINUES ALONG 13N30W TO 7N39W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 7N40W TO 6N49W. NO SIGNIFICANT DEEP CONVECTION IS OCCURRING OUTSIDE OF CONVECTION ASSOCIATED WITH THE TROPICAL WAVES MENTIONED ABOVE. ...DISCUSSION... GULF OF MEXICO... A MIDDLE-LEVEL INVERTED TROUGH IS OVER THE S-SW GULF SUPPORTING A TROPICAL WAVE MOVING ACROSS THE YUCATAN PENINSULA TONIGHT. SEE THE TROPICAL WAVES SECTION FOR MORE DETAILS. IN THE UPPER- LEVELS...TROUGHING FROM AN ELONGATED LOW OVER SW MEXICO COVERS THE WESTERN BASIN. TROUGHINESS ALOFT ALSO SUPPORT A SURFACE TROUGH ALONG 23N97W TO 17N95W...WHICH ENHANCES SCATTERED SHOWERS AND TSTMS S OF 23N W OF 92W. A TROUGH OF LOW PRESSURE IS ALONG THE FLORIDA PENINSULA FROM 30N81W TO 25N81W. LOW-LEVEL MOISTURE CONVERGENCE ALONG MIDDLE-LEVEL DIVERGENCE IN THE REGION SUPPORT SCATTERED SHOWERS AND ISOLATED TSTMS ACROSS MOST OF THE PENINSULA AND THE FLORIDA KEYS. OTHERWISE SHOWERS AND TSTMS ARE WITHIN 20 NM OFF THE NW GULF COASTLINE ASSOCIATED WITH A STATIONARY FRONT EXTENDING FROM THE SE CONUS SW TO SOUTHERN TEXAS. THE TROPICAL WAVE WILL BE MOVING ACROSS THE SW GULF MONDAY AND IS FORECAST TO MOVE TO E PAC WATERS BY EARLY TUE. LOW PRESSURE WILL DOMINATE ACROSS THE GULF THROUGH TUE. CARIBBEAN SEA... A MIDDLE-LEVEL INVERTED TROUGH DOMINATES THE BASIN TONIGHT WHICH ALONG WITH ABUNDANT MOISTURE PROVIDE A VERY UNSTABLE ENVIRONMENT ACROSS MUCH OF THE CARIBBEAN. THIS TROUGHINESS ALOFT IS SUPPORTING A TROPICAL WAVE MOVING ACROSS THE CENTRAL BASIN. SEE THE TROPICAL WAVES SECTION FOR MORE DETAILS. ON THE NW BASIN...THE PASSAGE OF A TROPICAL WAVE CURRENTLY MOVING ACROSS THE YUCATAN PENINSULA CONTINUE TO ENHANCE SCATTERED SHOWERS AND TSTMS N OF 16N WEST OF 74W. ON THE UPPER-LEVELS...A CYCLONIC CIRCULATION ANCHORED ON THE CENTRAL BAHAMAS EXTENDS A TROUGH SE ACROSS THE CENTRAL AND EASTERN CARIBBEAN GENERATING A DIFFLUENT ENVIRONMENT THAT SUPPORT THE CONVECTION OF THE AFOREMENTIONED TROPICAL WAVE...WHICH EXTENDS FROM HISPANIOLA TO PUERTO RICO AND NORTHERN ADJACENT WATERS. ON THE SW CARIBBEAN...THE MONSOON TROUGH CROSSES FROM COSTA RICA TO NORTHERN COLOMBIA AND ENHANCES SCATTERED SHOWERS AND TSTMS S OF 12N. TRADES OF 20-25 KT ARE ON THE CENTRAL BASIN ASSOCIATED WITH THE PASSAGE OF THE TROPICAL WAVE. TRADES OF 15 KT DOMINATE ELSEWHERE. THE TROPICAL WAVE IS EXPECTED TO MOVE WESTWARD AND OUT OF THE BASIN BY TUE NIGHT. ...HISPANIOLA... CURRENTLY HISPANIOLA IS INFLUENCED BY UPPER LEVEL WEST- NORTHWESTERLY WINDS ALOFT THAT TRANSITION TO MORE DIFFLUENT FLOW E OF 71W. WITH AN UPPER LEVEL LOW CENTERED OVER THE SW NORTH ATLC TO THE NORTH OF THE ISLAND NEAR 23N74W... MOISTURE AND CLOUDINESS CONTINUES TO ADVECT ACROSS THE ISLAND. IN ADDITION...A TROPICAL WAVE SUPPORTED BY A MIDDLE-LEVEL INVERTED TROUGH ENHANCES SCATTERED MODERATE CONVECTION AND TSTMS ACROSS WESTERN DOMINICAN REPUBLIC AND HAITI AND ADJACENT NORTHERN WATERS. RAINSHOWERS ARE EXPECTED ACROSS MUCH OF THE ISLAND THROUGH TUE MORNING. ATLANTIC OCEAN... AN UPPER-LEVEL LOW IS ANCHORED OVER THE CENTRAL BAHAMAS SUPPORTING SCATTERED MODERATE CONVECTION AND TSTMS S OF 26N BETWEEN 64W-78W. FARTHER EAST...A BROAD MIDDLE TO UPPER LOW SUPPORT A PAIR OF 1017 MB SURFACE LOW PRESSURE CENTERS...ONE NEAR 29N55W AND OTHER NEAR 28N49W...THE LATER DISSIPATING BY TOMORROW AFTERNOON. ON THE EASTERN ATLC...SURFACE RIDGING DOMINATE BEING ANCHORED BY A 1020 MB HIGH NEAR 27N34W. OTHERWISE...SEE THE TROPICAL WAVES SECTION ABOVE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR