000 AXNT20 KNHC 040606 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT WED SEP 04 2013 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...SPECIAL FEATURE... A BROAD AREA OF LOW PRESSURE WITH A 1008 MB CENTER NEAR 15N64W CONTINUES ENHANCING CONVECTIVE ACTIVITY OVER THE EASTERN CARIBBEAN. THE TROPICAL WAVE PREVIOUSLY ASSOCIATED WITH IT HAS DETACHED AND CONTINUED A WESTWARD TRACK. SCATTERED MODERATE CONVECTION AND TSTMS ARE FROM 15N-19N BETWEEN 62W-66W AS WELL AS ACROSS THE WINDWARD ISLANDS. UPPER-LEVEL WINDS APPEAR FAVORABLE FOR SOME DEVELOPMENT OVER THE NEXT FEW DAYS...BUT INTERACTION WITH THE LAND MASSES OF HISPANIOLA AND PUERTO RICO COULD INHIBIT TROPICAL CYCLONE FORMATION AS THE SYSTEM MOVES WEST- NORTHWESTWARD TO NORTHWESTWARD AT AROUND 10 MPH. CURRENTLY...THIS SYSTEM HAS A MEDIUM CHANCE...30 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. REGARDLESS OF TROPICAL CYCLONE FORMATION...LOCALLY HEAVY RAINFALL AND GUSTY WINDS ARE EXPECTED TO AFFECT PORTIONS OF THE NORTHERN LESSER ANTILLES FOR THE NEXT DAY OR SO...AND SPREAD OVER PUERTO RICO LATER TODAY. ...TROPICAL WAVES... A TROPICAL WAVE ASSOCIATED WITH A 1012 MB LOW PRESSURE CENTER CAME OFF THE AFRICAN COAST EARLIER TODAY AND CURRENTLY IS MOVING ACROSS THE CAPE VERDE ISLANDS. ITS AXIS EXTENDS FROM 19N23W TO THE LOW NEAR 13N24W TO 08N23W AND IS MOVING NEAR 10 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOW HIGH MOISTURE E OF THE LOW CENTER...A MODERATE MOIST ENVIRONMENT S OF IT BUT A MUCH DRIER ENVIRONMENT NW OF THE LOW SINCE THE WAVE IS BEING ENGULFED BY SAHARAN DRY AIR AND DUST. THEREFORE...DEEP CONVECTION IS BEING HINDERED. WIDELY SCATTERED MODERATE CONVECTION IS SW OF THE LOW FROM 08N-13N BETWEEN 24W-30W AS WELL AS E-NE OF THE LOW FROM 13N- 16N. A TROPICAL WAVE IS OVER THE CENTRAL TROPICAL ATLC EXTENDING AN AXIS FROM 22N41W TO 10N38W AND MOVING WEST NEAR 5 KT. METEOSAT SAL TRACKING IMAGERY SHOW THIS WAVE IS BETWEEN TWO SAHARAN DRY AIRMASSES WHICH ARE LIMITING CONVECTIVE ACTIVITY. TOTAL PRECIPITABLE WATER IMAGERY SHOW THE WAVE AXIS IS EMBEDDED WITHIN A FINE ELONGATED LINE OF MODERATE MOISTURE. ISOLATED SHOWERS ARE N OF THE AXIS FROM 21N-27N BETWEEN 40W-43W AS WELL AS FROM 15N- 17N BETWEEN 42W-43W. A TROPICAL WAVE IS APPROACHING THE LESSER ANTILLES. ITS AXIS EXTENDS FROM 21N57W TO 11N55W AND IS MOVING W NEAR 5 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOW THAT MOISTURE HAS BEEN INCREASING AND AMPLIFIED WITHIN THE LAST COUPLE OF HOURS AND CONVECTION LOOKS MORE ORGANIZED. NUMEROUS MODERATE CONVECTION CONCENTRATE OVER THE NORTH-CENTRAL WAVE FROM 15N-19N BETWEEN 54W- 59W. A TROPICAL WAVE PREVIOUSLY ASSOCIATED WITH A BROAD AREA OF LOW PRESSURE IN THE EASTERN CARIBBEAN HAS DETACHED FROM IT AND MOVED WESTWARD TOWARDS THE CENTRAL CARIBBEAN SEA. THE NORTHERN PORTION OF THE AXIS IS OVER HAITI NEAR 19N73W AND CONTINUES ALONG 14N73W TO NORTHERN COLOMBIA NEAR 10N73W. SHOWERS AND TSTMS CONCENTRATE OVER HAITI AND ADJACENT SOUTHERN WATERS BEING ENHANCED BY UPPER LEVEL DIFFLUENCE. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 18N16W AND CONTINUES ALONG 10N20W TO 07N30W TO 07N38W. THE ITCZ AXIS EXTENDS FROM 07N38W TO 11N50W. BESIDES THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES ALREADY DISCUSSED...SCATTERED MODERATE CONVECTION IS FROM 14N-21N E OF 20W AS WELL AS FROM 02N-08N BETWEEN 24W-34W. ...DISCUSSION... THE GULF OF MEXICO... A NARROW UPPER LEVEL TROUGH SUPPORTS A FRONTAL SYSTEM N OF THE AREA. A PRE-FRONTAL SURFACE TROUGH EXTENDS OVER THE NE GULF FROM THE FLORIDA PANHANDLE NEAR 30N84W TO 30N85W TO SE LOUISIANA NEAR 29N90W. THIS TROUGHINESS IS ENHANCING SCATTERED SHOWERS OVER SE LOUISIANA WHICH EXTENDS WITHIN 20 NM FROM ITS COAST BETWEEN 90W- 93W. ISOLATED SHOWERS ARE POSSIBLE OVER THE NE GULF N OF 29N. A SURFACE TROUGH EXTENDS FROM 26N86W TO THE YUCATAN PENINSULA NEAR 21N89W TO GUATEMALA NEAR 16N90W. MOST OF THE CONVECTION ASSOCIATED WITH THIS TROUGH IS INLAND MEXICO SUPPORTED BY AREAS OF UPPER LEVEL DIFFLUENCE. HOWEVER...SCATTERED SHOWERS ASSOCIATED WITH IT ARE ACROSS THE FLORIDA STRAITS AND ISOLATED SHOWERS ELSEWHERE IN THE EASTERN GULF S OF 28N E OF 92W. A SURFACE HIGH PRESSURE IS EXPECTED TO DEVELOP OVER THE NE GULF THIS AFTERNOON. THE TROUGH ALONG THE EASTERN GULF WILL MOVE WESTWARD TOWARDS THE BAY OF CAMPECHE WHERE A LOW PRESSURE CENTER IS EXPECTED TO DEVELOP ASSOCIATED WITH IT. THAT AREA OF LOW PRESSURE OVER THE SW GULF IS EXPECTED TO PERSIST THROUGH FRIDAY AFTERNOON. THE CARIBBEAN SEA... A CLUSTER OF MODERATE CONVECTION IS OVER THE FAR NW CARIBBEAN SEA S OF 21N W OF 85W ASSOCIATED WITH THE SURFACE TROUGH ACROSS THE EASTERN GULF AND BEING ENHANCED BY UPPER LEVEL DIFFLUENCE. AN ELONGATED UPPER LEVEL LOW IS BETWEEN WESTERN HAITI AND EASTERN CUBA. THE WESTERN PERIPHERY OF AN UPPER LEVEL HIGH SPREADS ACROSS THE EASTERN CARIBBEAN TO GENERATE DIFFLUENCE ALOFT OVER WESTERN HISPANIOLA. A TROPICAL WAVE PREVIOUSLY ASSOCIATED WITH A BROAD AREA OF LOW PRESSURE IN THE EASTERN CARIBBEAN HAS DETACHED FROM IT AND MOVED WESTWARD TOWARDS THE CENTRAL CARIBBEAN SEA. THE NORTHERN PORTION OF THE AXIS IS OVER HAITI NEAR 19N73W AND CONTINUES ALONG 14N73W TO NORTHERN COLOMBIA NEAR 10N73W. SHOWERS AND TSTMS CONCENTRATE OVER HAITI AND ADJACENT SOUTHERN WATERS BEING ENHANCED BY THE AFOREMENTIONED UPPER LEVEL DIFFLUENCE. SCATTERED MODERATE CONVECTION IS OVER THE SOUTHERN GULF S OF 12N E OF 81W ASSOCIATED WITH THE MONSOON TROUGH AND A 1005 MB LOW PRESSURE OVER NORTHERN COLOMBIA. A BROAD AREA OF LOW PRESSURE WITH A 1008 MB CENTER NEAR 15N64W CONTINUES ENHANCING CONVECTIVE ACTIVITY OVER THE EASTERN CARIBBEAN. SCATTERED MODERATE CONVECTION AND TSTMS ARE FROM 15N-19N BETWEEN 62W-66W AS WELL AS ACROSS THE WINDWARD ISLANDS. SEE THE SPECIAL FEATURE SECTION FOR MORE INFORMATION ABOUT THIS INVEST AREA. HISPANIOLA... THE NORTHERN PORTION OF A TROPICAL WAVE AXIS IS OVER HAITI NEAR 19N73W AND CONTINUES ALONG 14N73W TO NORTHERN COLOMBIA NEAR 10N73W. SHOWERS AND TSTMS CONCENTRATE OVER HAITI AND ADJACENT SOUTHERN WATERS BEING ENHANCED BY UPPER LEVEL DIFFLUENCE. EXPECT MORE CONVECTION OVER THE NEXT 24 HOURS. THE ATLANTIC OCEAN... BESIDES THE TROPICAL WAVES ALREADY DISCUSSED...SURFACE RIDGING ANCHORED BY A SET OF HIGH PRESSURE CENTERS N OF THE AREA DOMINATES THE REMAINDER BASIN N OF 23N WHICH ALONG WITH DRY STABLE AIR SUPPORTS FAIR WEATHER. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR