000 AXNT20 KNHC 141803 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE AUG 14 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 1700 UTC. ...SPECIAL FEATURES... A SURFACE TROUGH IS IN THE CENTRAL ATLC ALONG 29N48W TO 22N51W. IT ORIGINATED AS A BROKEN OFF PIECE OF A TROPICAL WAVE THAT IS APPROACHING THE LESSER ANTILLES. CONVECTION NEAR THE TROUGH HAS INCREASED FROM 24 HOURS AGO. CURRENTLY SCATTERED MODERATE CONVECTION IS FROM 23N-28N BETWEEN 49W-54W. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO BECOME MORE CONDUCIVE FOR DEVELOPMENT OVER THE NEXT COUPLE OF DAYS. THE TROUGH IS FORECAST TO MOVE NW AROUND THE SURFACE RIDGE TO THE N. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 20N29W TO 9N29W MOVING W AT 20 KT. THE WAVE LIES ON THE WEST SIDE OF A SURGE OF DEEP LAYER MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. THERE IS ALSO A CLEARING THE IN THE SAHARAN AIR LAYER AND AFRICAN DUST PRESENT ACROSS MUCH OF THE EASTERN ATLC. THIS DRY AIRMASS SURROUNDING THE WAVE IS LIMITING DEEP CONVECTION TO THE MONSOON TROUGH REGION. SCATTERED MODERATE CONVECTION IS FROM 6N-8N BETWEEN 29W-36W. SIMILAR CONVECTION IS FROM 8N-10N BETWEEN 22W-28W. TROPICAL WAVE EXTENDS FROM 16N52W TO 8N54W MOVING W NEAR 20 KT. THE WAVE HAS LOST MOST OF ITS ENERGY TO THE SURFACE TROUGH TO THE N...WHICH BROKE OFF OF THE WAVE. THE WAVE STILL ALIGNS WITH A WEAK SURGE OF MODERATE DEEP LAYER MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. NO DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THE WAVE. TROPICAL WAVE...REMNANTS OF T.D. SEVEN...IS MOVING W AT 15-20 KT THROUGH THE WESTERN CARIBBEAN FROM 20N81W TO 10N81W. SATELLITE IMAGERY ALONG WITH SURFACE OBSERVATIONS INDICATE SHARP CYCLONIC SURFACE FLOW IS AROUND THE AXIS. THE WAVE ALSO LIES UNDERNEATH AN AREA OF DIFFLUENCE ALOFT...WHICH IS HELPING PRODUCE SHOWERS/THUNDERSTORMS NEAR THE WAVE. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS FROM 10N-15N BETWEEN 74W-79W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 10N-19N BETWEEN 79W-85W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF MAURITANIA AT 19N16W CONTINUING ACROSS ATLC WATERS ALONG 12N22W 8N30W 7N39W. THE ITCZ BEGINS AT 7N39W TO 8N52W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 10N-16N BETWEEN 15W-20W. ...DISCUSSION... GULF OF MEXICO... WEAK SURFACE RIDGING COVERS THE MAJORITY OF THE GULF OF MEXICO CENTERED AROUND A 1017 MB HIGH NEAR 27N86W. THE RIDGE IN COMBINATION WITH DRY AIR ALOFT AROUND THE NORTHERN SIDE OF AN UPPER LEVEL RIDGE CENTERED OVER CENTRAL MEXICO IS HELPING PROVIDE FAIR CONDITIONS OVER MUCH OF THE AREA. AN AREA OF SHOWERS/POSSIBLE THUNDERSTORMS IS OFF THE COAST OF MEXICO FROM 20N-24N BETWEEN 96W-98W. ANOTHER AREA OF STRONGER SHOWERS/THUNDERSTORMS IS ALSO OVER THE FLORIDA PANHANDLE DUE TO DIFFLUENCE ALOFT AROUND AN UPPER LEVEL TROUGH OVER THE EASTERN CONUS. A FEW ISOLATED SHOWERS ARE ALSO EMBEDDED WITHIN THE LIGHT ANTI-CYCLONIC FLOW AROUND THE SURFACE HIGH CENTER. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS. MOISTURE FROM A TROPICAL WAVE IN THE WESTERN CARIBBEAN MAY BEGIN TO IMPACT THE SE GULF. CARIBBEAN SEA... A TROPICAL WAVE IN COMBINATION WITH DIFFLUENCE ALOFT AROUND AN INVERTED UPPER TROUGH OVER CENTRAL AMERICA IS HELPING PRODUCE SHOWERS/THUNDERSTORMS ACROSS MUCH OF THE WESTERN CARIBBEAN FROM 10N-19N BETWEEN 73W-84W. THE REMAINDER OF THE BASIN IS EXPERIENCING MOSTLY FAIR WEATHER DUE TO DRY AIR ALOFT AROUND AN UPPER LEVEL RIDGE IN THE CENTRAL CARIBBEAN. TRADEWIND FLOW OF 15-20 KT IS PRESENT ACROSS THE EASTERN AND CENTRAL CARIBBEAN. EXPECT THE WAVE TO CONTINUE WESTWARD WITH LITTLE CHANGE ELSEWHERE. ATLANTIC OCEAN... AN UPPER LEVEL RIDGE COVERS THE W ATLC SUPPORTING A WEAK SURFACE RIDGE. HOWEVER...AN UPPER LEVEL TROUGH OVER THE EASTERN CONUS IS SUPPORTING SHOWERS/THUNDERSTORMS N OF 27N BETWEEN 74W-79W. THE UPPER TROUGH ALSO SUPPORTS A SURFACE TROUGH THAT ENTERS THE AREA FROM 32N78W TO 30N79W. A NARROW UPPER TROUGH IS TO THE E ALONG 62W...BUT IS NOT CAUSING ANY SIGNIFICANT WEATHER. AN UPPER LEVEL RIDGE COVERS THE CENTRAL ATLC CENTERED NEAR 33N48W SUPPORTING A 1025 MB HIGH NEAR 33N46W. A SURFACE TROUGH TO THE SOUTH IS CAUSING AN AREA OF ACTIVE WEATHER. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS ON THE TROUGH. AN UPPER LEVEL TROUGH COVERS THE NE ATLC WITH A NARROW AXIS CONTINUING INTO THE DISCUSSION AREA FROM THE CANARY ISLANDS TO NEAR 25N36W. THE TROUGH IS SUPPORTING A COLD FRONT N OF THE DISCUSSION AREA...BUT NO SIGNIFICANT WEATHER IN THE DISCUSSION AREA. VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW AN AREA OF DUST EXTENDS FROM THE COAST OF AFRICA AROUND THE TROPICAL WAVE IN THE EASTERN TROPICAL ATLC. THE DRY AIR MASS IS LIMITING CONVECTION NEAR THE WAVE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON