000 AXNT20 KNHC 071805 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SAT JUL 07 2012 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1745 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS MOVING ACROSS THE CENTRAL ATLC EXTENDS IN A NW TO SE FASHION FROM 23N49W TO NEAR 14N48W MOVING W AT 17 KT. MOISTURE IS VERY LIMITED WITH THIS WAVE AS IT TRAVERSES A VERY STABLE AND DRY ENVIRONMENT MARKED BY THE EASTERN MOST PERIPHERY OF SAHARAN DUST. SATELLITE IMAGERY FROM DURING THE DAY SHOWS A SMALL POCKET OF LOW TO MID LEVEL MOISTURE WITH SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 120-180 NM W OF THE WAVE FROM 18N-23N. LATEST TPW ANIMATION IMAGERY FAINTLY DEPICTS THIS AREA OF MOISTURE WITH THE WAVE. TROPICAL WAVE IS ADVANCING ACROSS THE THE WRN CARIBBEAN SEA STRETCHING FROM WRN CUBA SW TO GULF OF HONDURAS MOVING W NEAR 17 KT...BASED ON 24 HR EXTRAPOLATED MOTION. THE NORTHERN PORTION OF THIS WAVE HAS DISLODGE FROM IT...AND IS NOW A SURFACE TO LOW LEVEL TROUGH THAT EXTENDS FROM NW CUBA NE TO THE STRAITS OF FLORIDA AND JUST TO THE SE OF S FLORIDA WHERE A WEAK SURFACE TO LOW LEVEL CYCLONIC SWIRL WAS EARLIER NOTED. SCATTERED SHOWERS AND TSTMS ARE QUICKLY DEVELOPING ALONG AND TO THE W OF THIS FEATURE. THE REMAINDER OF THE WAVE REMAINS EMBEDDED IN A LARGE SURGE OF DEEP LAYER MOISTURE COVERING THE WRN PORTION OF THE SEA W OF 80W. TPW ANIMATION VIVIDLY DISPLAYS THIS BULGE OF MOISTURE...AND SATELLITE IMAGERY SHOWS NUMEROUS SHOWERS AND TSTMS CONFINED TO SW OF A LINE FROM 21N86W TO 15N81W TO 11N79W. EXPECT THIS ACTIVITY TO BRING PERIODS OF HEAVY RAINFALL TO EASTERN YUCATAN PENINSULA...BELIZE...HONDURAS AND NICARAGUA TONIGHT THEN OVER THE REMAINDER OF THESE LOCATIONS SUN THROUGH MON NIGHT. VISIBLE SATELLITE IMAGERY FROM DURING THE DAY REVEAL MOISTURE CONCENTRATION IN THE SW MONSOONAL FLOW INTO FAR WRN AFRICA. MODEL GUIDANCE FIELDS AT 700 MB ALONG WITH POTENTIAL VORTICITY GUIDANCE SUGGEST THAT THE NEXT WAVE TO MOVE OFF THE COAST OF AFRICA SHOULD OCCUR WITHIN THE NEXT 24-36 HRS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS SW FROM THE W COAST OF AFRICA AT COAST OF GUINEA BISSAU NEAR 13N16W...AND EXTENDS SW TO A 1012 MB LOW AT 10N23N AND TO 8N28W...WHERE SCATTEROMETER DATA FROM THIS MORNING SUGGEST THE ITCZ BEGINS AND EXTENDS TO ANOTHER 1012 MB LOW AT 7N40W AND TO THE COAST OF S AMERICA AT 7N58W. SCATTERED STRONG CONVECTION IS JUST INLAND THE COAST OF GUINEA BISSAU. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF THE MONSOON TROUGH BETWEEN 21W-25W...AND IS ALSO RELATED TO THE 1012 MB LOW. OTHERWISE...SCATTERED ISOLATED MODERATE CONVECTION IS ELSEWHERE WITHIN ABOUT 60 NM EITHER SIDE OF THE ITCZ. ...DISCUSSION... GULF OF MEXICO... A BROAD AREA OF UPPER LEVEL RIDGING COVERS THE ERN CONUS WITH ITS S AND SW PERIPHERY EXTENDING SW OVER THE NRN AND CENTRAL GULF. FAST UPPER LEVEL ELY FLOW ACROSS THESE PORTIONS OF THE GULF DUE TO THE FLOW PATTERN SET UP BETWEEN THE HIGH AND AN ELONGATED UPPER LOW OVER THE SE GULF IS STEERING TSTM ACTIVITY ASSOCIATED WITH MESOSCALE OUTFLOW BOUNDARIES OVER THE FAR NRN N OF 28N AND BETWEEN 88W AND 93W WWD TOWARDS THE NE TEXAS AND SW LOUISIANA REGIONS. A WEAK 1019 MB SURFACE HIGH IS IN THE NE GULF AT 28N84W WITH A RIDGE WSW TO CENTRAL TEXAS. ONLY SCATTERED LOW CLOUDS WITH ISOLATED SHOWERS AND TSTMS ARE NOTED ELSEWHERE ACROSS THE GULF. SCATTERED SHOWERS AND TSTMS ARE MOVING W ACROSS THE STRAITS OF FLORIDA...AND ENTERING THE FAR SE GULF WATERS IN ASSOCIATION WITH THE SURFACE TO LOW LEVEL TROUGH MENTIONED ABOVE UNDER TROPICAL WAVES. WEAK SURFACE RIDGING IS EXPECTED TO REMAIN ACROSS THE BASIN THROUGH THE WEEKEND. CARIBBEAN SEA... ASIDE FROM CONVECTION MENTIONED UNDER TROPICAL WAVES...MOSTLY FAIR WEATHER CONDITIONS ARE BEING OBSERVED ELSEWHERE ACROSS THE BASIN DUE TO A COMBINATION OF DRY AIR ALOFT AND SOME SAHARAN DUST INTRUSION FROM THE PREVIOUS DAYS INTO THE AREA. EASTERLY TRADE WIND FLOW OF 15-25 KT IS ACROSS MUCH OF THE BASIN...EXCEPT HIGHER IN THE 25-30 KT WITH IN THE SW PORTION FROM 12N-14N BETWEEN 70W-78W. THESE HIGHER WINDS ARE EXPECTED TO LAST ANOTHER 24 HRS BEFORE DIMINISHING SOME. ATLANTIC OCEAN... EARLIER CONVECTIVE ACTIVITY NOTED ACROSS AND NEAR THE BAHAMAS HAS DIMINISHED. THIS ACTIVITY WAS LEFT BEHIND BY THE TROPICAL A BROAD AND STRONG 1031 MB HIGH PRESSURE SYSTEM CENTERED NNW OF THE AZORES EXTENDS A SURFACE RIDGE AXIS TO THE WRN ATLC KEEPING FAIR WEATHER CONDITIONS ELSEWHERE ACROSS THE REMAINDER OF THE DISCUSSION AREA. THE FAIR WEATHER IS FURTHER ENHANCED BY A LARGE AREA OF SAHARAN DUST EXTENDING FROM THE WEST AFRICA TO THE ERN CARIBBEAN...AND LITTLE OVERALL CHANGE IS EXPECTED OVER THE NEXT 24-48 HRS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ AGUIRRE