000 AXNT20 KNHC 261748 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT THU JUL 26 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 1735 UTC. ...TROPICAL WAVES... TROPICAL WAVE AXIS MOVES ACROSS THE ERN TRPCL ATLC ANALYZED FROM 18N30W TO 10N32W. THIS SYSTEM WAS LABELED AS A LOW PRESSURE SYSTEM ON PREVIOUS SURFACE MAPS. HOWEVER...AS THE SYSTEM MOVES OVER UNFAVORABLE REGIONS OF DEVELOPMENT...IT'S LOW LEVEL CENTER HAS WEAKENED EXPOSING ONLY A WAVE AXIS. THIS SCENARIO WAS CONCLUDED THIS MORNING AS AN ASCAT SCATTEROMETER PASS WENT OVER THIS REGION INDICATING THE ELONGATED CYCLONIC CURVATURE ALONG THE WAVE AXIS...WHICH IS FOUND WEST OF A REGION OF DEEP LAYER OF MOISTURE DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY. SOME MID LEVEL CYCLONIC CURVATURE REMAINS AROUND THE WAVE AXIS ON THE CLOUD PATTERN ON EARLY VISIBLE SATELLITE PICTURES OF THE DAY. THE RAIN AND THUNDERSTORM ACTIVITY REMAINS MOSTLY S OF THE WAVE AXIS WHERE THE MONSOON TROUGH IS ANALYZED. TROPICAL WAVE MOVES ACROSS THE CENTRAL TROPICAL ATLC WITH AXIS ANALYZED FROM 23N45W TO THE MONSOON TROUGH AXIS NEAR 11N48W MOVING W AT ABOUT 5-10 KT. THE WAVE REMAINS ALONG THE WRN EDGE OF A SURGE OF DEEP LAYER MOISTURE DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER...THIS SYSTEM IS EMBEDDED IN A DENSE REGION OF SAHARAN DUST LIMITING THE CONVECTIVE ACTIVITY AROUND THE WAVE TO NEAR ZERO. A TROPICAL WAVE MOVES ACROSS THE N-WESTERN CARIBBEAN WITH AXIS ANALYZED FROM THE WRN TIP OF CUBA NEAR 22N84W TO INLAND OVER N-CENTRAL NICARAGUA NEAR 14N85W. WAVE REMAINS ON THE WRN EDGE OF A SURGE OF DEEP MOISTURE NOTED ON TOTAL PRECIPITABLE WATER IMAGERY. AN UPPER LEVEL INVERTED TROUGH MOVES ACROSS CENTRAL AMERICA AND YUCATAN PENINSULA ON WATER VAPOR IMAGERY. THIS FEATURE ALONG WITH LOW LEVEL MOISTURE CONVERGENCE IN THE VICINITY OF THE WAVE AXIS IS GENERATING AN AREA OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS S OF 19N W OF 82W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE TROPICAL ATLC THROUGH THE COAST DAKAR SENEGAL TO JUST EAST OF THE ERN ATLC TROPICAL WAVE NEAR 13N28W...RESUMING SW OF THE SAME TROPICAL WAVE NEAR 10N32W CONTINUING WESTWARD ALONG 11N44W TO 9N52W...WHERE A SHORT SECTION OF THE ITCZ CONTINUES TO THE COAST OF GUYANA NEAR 7N58W. CLUSTERS OF SCATTERED MODERATE TO STRONG CONVECTION ARE FROM 6N-11N BETWEEN 50W-60W. SIMILAR CONVECTION IS FOUND S OF ERN ATLC TROPICAL WAVE FROM 6N-11N BETWEEN 28W-38W. SCATTERED WEAK TO ISOLATED MODERATE CONVECTION IS WITHIN 170 NM OFF THE COAST OF WEST AFRICA FROM SIERRA LEONE TO GUINEA-BISSAU. ...DISCUSSION... GULF OF MEXICO... A SURFACE TROUGH IS ANALYZED FROM THE NRN FLORIDA PENINSULA NEAR 30N83W TO 28N84W. DOPPLER RADAR IMAGERY SHOWS SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS N OF 27N E OF 89W. AN UPPER INVERTED TROUGH BEGAN TO INTERACT WITH THE SURFACE FEATURE THIS MORNING AND IT WILL CONTINUE TO SUPPORT THE SHOWER ACTIVITY IN THIS REGION OVER THE NEXT 24 HOURS...AS AN UPPER TROUGH MOVING ACROSS THE CENTRAL CONUS TAKES OVER THE ERN AND SE CONUS DURING THE NEXT 24-48 HOURS. THIS WILL LIKELY KEEP THE CONVECTION OVER THE NE AND N-CENTRAL GULF FAIRLY ACTIVE DURING THE FORECAST PERIOD. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE DEPICTED ON SATELLITE IMAGERY WITHIN 80 NM OFF THE TEXAS/MEXICO COAST FROM 24N-29N. THE ACTIVITY IS EXPECTED TO MOVE N OVER THE NEXT 24 HOURS. A TROPICAL WAVE CURRENTLY MOVING ACROSS THE NW CARIBBEAN WILL BEGIN TO AFFECT THE YUCATAN PENINSULA AND ERN BAY OF CAMPECHE OVER THE WEEKEND. CARIBBEAN SEA... THE ONLY REGION OF ACTIVE WEATHER ACROSS THE CARIBBEAN THIS AFTERNOON IS FOUND OVER THE NW BASIN...DUE TO THE PASSAGE OF A TROPICAL WAVE WITH AXIS ANALYZED BETWEEN WRN CUBA AND CENTRAL HONDURAS. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE S OF 19N W OF 82W. THIS AREA OF CONVECTION WILL CONTINUE TO MOVE INLAND OVER THE YUCATAN PENINSULA DURING THE NEXT 24 HOURS. FOR MORE DETAILS SEE TROPICAL WAVES DISCUSSION ABOVE. VISIBLE SATELLITE IMAGERY SHOWS THE REMAINDER OF THE DISCUSSION AREA UNDER FAIR WEATHER CONDITIONS. THIS ENVIRONMENT IS HEAVILY RELATED TO STRONG SUBSIDENCE AND DRY AIR ALOFT NOTED ON WATER VAPOR IMAGERY...IN COMBINATION WITH SAHARAN DUST ALOFT NOTED ON MOST UPPER AIR SOUNDINGS AVAILABLE ACROSS THE CARIBBEAN ISLANDS. ATLANTIC OCEAN... AN UPPER RIDGE COVERS THE FAR WRN ATLC ANCHORED BY A 1015 MB HIGH N OF THE DISCUSSION AREA NEAR 35N70W. HOWEVER...AN UPPER TROUGH IS TO THE E OF THE UPPER RIDGE...COVERING THE REMAINDER OF THE WRN ATLC INTO THE CENTRAL ATLC SUPPORTING A COLD FRONT THAT ENTERS THE REGION NEAR 32N62W CONTINUING WSW ALONG 29N68W TO 30N72W WHERE IT BECOMES STATIONARY AS IT CONTINUES OUT OF THE REGION ALONG 32N75W. THIS FRONTAL BOUNDARY IS GENERATING AN AREA OF SCATTERED SHOWERS AND THUNDERSTORMS WITHIN 150 NM SE OF THE BOUNDARY E OF 70W. THE COLD FRONT AND ASSOCIATED CONVECTION IS FORECAST TO MOVE EASTWARD BEFORE LOOSING MOMENTUM AND BECOMING STATIONARY DURING THE NEXT 24 HOURS. OTHERWISE...BROAD UPPER LEVEL RIDGING COVERS THE REMAINDER OF THE ATLC DISCUSSION AREA. THE FAIR WEATHER IS FURTHER ENHANCED BY SAHARAN DUST COVERING THE ENTIRE ATLC DISCUSSION AREA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA