000 AXNT20 KNHC 222345 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED AUG 22 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... THE CENTER OF TROPICAL STORM ISAAC AT 22/0000 UTC IS NEAR 15.7N 62.2W...MOVING WEST AT 19 KNOTS. THIS POSITION IS ABOUT 55 NM SW OF GUADELOUPE...OR ABOUT 280 NM SE OF SAN JUAN PUERTO RICO. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004 MB. THE MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. OUTER RAINBANDS ARE ALREADY BEGINNING TO IMPACT PUERTO RICO WITH SCATTERED MODERATE CONVECTION PRESENT FROM 16N-20N BETWEEN 61W-67W. A LARGE CLUSTER OF STRONG CONVECTION IS NEAR THE CENTER OF THE STORM FROM 14N-17N BETWEEN 58W-61W...AND W OF THE LESSER ANTILLES FROM 14N-16N BETWEEN 62W-65W. SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM 11N-16N BETWEEN 54W-66W. PLEASE READ THE FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC AND THE PUBLIC ADVISORY...MIATCPAT4/WTNT34 KNHC FOR MORE DETAILS. THE CENTER OF TROPICAL DEPRESSION TEN AT 22/2100 UTC IS NEAR 13.1N 37.4W...MOVING WNW AT 14 KNOTS. THIS POSITION IS ABOUT 800 NM W OF THE CAPE VERDE ISLANDS. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 30 KT WITH GUSTS TO 40 KT. A CLUSTER OF STRONG CONVECTION IS W OF THE CENTER FROM 12N-14N BETWEEN 39W-40W. SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM 11N-14N BETWEEN 36W-40W. PLEASE READ THE FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC AND THE PUBLIC ADVISORY...MIATCPAT5/WTNT35 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE IS MOVING THROUGH THE CENTRAL CARIBBEAN ALONG 18N71W TO 8N72W MOVING W AT 15-20 KT. THE WAVE ALIGNS WITH A SURGE OF MODERATE MOISTURE VALUES PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER...DUE TO DRY AIR ALOFT PRESENT ACROSS MUCH OF THE CARIBBEAN WEST OF TROPICAL STORM ISSAC...NO DEEP CONVECTION IS NEAR THE WAVE. TROPICAL WAVE IS MOVING THROUGH THE SW GULF OF MEXICO ALONG 21N96W TO 13N95W MOVING W AT 12 KT. THE WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP LAYER MOISTURE PRESENT ACROSS THE NORTHERN AND WESTERN GULF. SCATTERED MODERATE/ISOLATED STRONG CONVECTION HAS POPPED UP EAST OF THE WAVE AXIS ACROSS MEXICO FROM 15N-19N BETWEEN 91W-95W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS WEST AFRICA TO A 1007 M SURFACE LOW ON THE COAST OF MAURITANIA AT 19N16W. THE AXIS THEN CONTINUES OVER WATER THROUGH THE CAPE VERDE ISLANDS ALONG 17N22W 17N28W. SCATTERED MODERATE/STRONG CONVECTION IS S OF THE MONSOON TROUGH AXIS FROM 10N-13N BETWEEN 14W-20W. ...DISCUSSION... THE GULF OF MEXICO... AN UPPER LEVEL TROUGH OVER THE EASTERN CONUS IS SUPPORTING A LOT OF SHOWER ACTIVITY OVER THE NORTHERN GULF OF MEXICO NEAR A SURFACE TROUGH EXTENDING FROM THE FLORIDA PANHANDLE AT 31N84W TO 27N88W 26N94W...AS OF 2100 UTC. SHOWERS/THUNDERSTORMS ARE WITHIN 180 NM EITHER SIDE OF THE AXIS WITH THE MOST CONCENTRATED ACTIVITY ALONG A LINE ABOUT 130 NM S OF THE AXIS. A SECOND...MORE VERTICALLY ALIGNED SURFACE TROUGH IS PARALLEL TO THE NE MEXICAN COAST ALONG 26N97W TO 22N97W...AS OF 2100 UTC. A FEW ISOLATED SHOWERS ARE WITHIN 120 NM EITHER SIDE OF THE AXIS. A TROPICAL WAVE IS S OF THIS AREA IN THE BAY OF CAMPECHE. THE WAVE IS NOT CAUSING MUCH ACTIVE WEATHER BESIDES SOME SCATTERED SHOWERS/THUNDERSTORMS INLAND OVER MEXICO. DRY AIR ALOFT ACROSS THE SE GULF IS PROVIDING FAIR CONDITIONS ACROSS THIS PORTION OF THE BASIN. SHOWERS/THUNDERSTORMS ARE EXPECTED TO REMAIN OVER THE NORTHERN GULF IN ASSOCIATION WITH THE UPPER TROUGH OVER THE EASTERN CONUS THAT IS EXPECTED TO REMAIN MOSTLY STATIONARY. THE CARIBBEAN SEA... TROPICAL STORM ISAAC IS THE MAIN WEATHER MAKER IN THE CARIBBEAN CURRENTLY IMPACTING THE EASTERN CARIBBEAN. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. THE REMAINDER OF THE BASIN IS FAIRLY DRY WITH ONLY A FEW SHOWERS/THUNDERSTORMS POPPING UP SOUTH OF EASTERN CUBA AND OVER JAMAICA. THESE ARE LIKELY ASSOCIATED WITH AN UPPER LEVEL LOW CENTERED OVER EASTERN CUBA. HOWEVER...DRY AIR IS AROUND THE REMAINDER OF THE UPPER TROUGH/LOW LIMITING SHOWER ACTIVITY NEAR A TROPICAL WAVE MOVING THROUGH THE CENTRAL CARIBBEAN. NO ACTIVE WEATHER IS PRESENT EXCEPT FOR SOME SHOWERS/THUNDERSTORMS INLAND OVER COLOMBIA. UPPER LEVEL RIDGING COVERS THE EASTERN HALF OF THE BASIN. INTERESTS IN THE CARIBBEAN SHOULD MONITOR THE PROGRESS OF TROPICAL STORM ISAAC AS IT MOVES WESTWARD. THE ATLANTIC OCEAN... AN UPPER LEVEL TROUGH OVER THE EASTERN CONUS IS SUPPORTING A LINE OF SHOWERS/THUNDERSTORMS EXTENDING FROM THE GULF OF MEXICO ACROSS FLORIDA AND INTO THE WEST ATLC ALONG 27N81W TO 31N76W. THE REMAINDER OF THE WEST ATLC IS EXPERIENCING MOSTLY FAIR WEATHER DUE TO DRY AIR ALOFT AROUND AN UPPER LEVEL TROUGH CENTERED OVER EASTERN CUBA. AN UPPER LEVEL RIDGE IS TO THE EAST EXTENDING N OF TROPICAL STORM ISAAC. A SECOND UPPER LEVEL RIDGE IS CENTERED FARTHER N NEAR 38N46W. THIS PAIR OF UPPER RIDGES IS HELPING SUPPORT A 1023 MB HIGH NEAR 34N56W. THE SECOND UPPER RIDGE IS ALSO SUPPORTING A FEW MORE HIGH CENTERS FARTHER EAST. AN UPPER LEVEL LOW IS ACROSS THE CENTRAL ATLC CENTERED NEAR 21N48W...BUT IT IS NOT CAUSING ANY SIGNIFICANT WEATHER IN THE DISCUSSION AREA. THE REMAINDER OF THE EASTERN ATLC IS ALSO DOMINATED BY AN UPPER LEVEL RIDGE CENTERED NW OF THE CAPE VERDE ISLANDS. BESIDES T.D. TEN AND T.S. ISAAC...FAIR CONDITIONS PREVAIL ACROSS THE CENTRAL AND EASTERN ATLC. THE LAST VISIBLE SATELLITE IMAGES OF THE DAY INDICATE A LARGE AREA OF DUST EXTENDS FROM THE COAST OF AFRICA TO NEAR 35W. A SECOND AREA OF DUST IS BETWEEN THE TWO TROPICAL CYCLONES. THE DUST IS HELPING CONTRIBUTE TO FAIR CONDITIONS ACROSS MUCH OF THE ATLC. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON