000 AXNT20 KNHC 131753 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT MON AUG 13 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. ...TROPICAL WAVES... TROPICAL WAVE IS APPROACHING THE CAPE VERDE ISLANDS ALONG 22N20W TO 11N21W MOVING W AT 10-15 KT. THE WAVE ALIGNS WITH 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. ISOLATED MODERATE CONVECTION IS FROM 8N-14N BETWEEN 16W-21W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 7N-10N BETWEEN 21W-30W. TROPICAL WAVE EXTENDS FROM 26N41W TO 18N45W THROUGH A 1016 MB SURFACE LOW ALONG THE AXIS AT 22N44W MOVING W AT 20 KT. THE SATELLITE REPRESENTATION OF THE WAVE IS WELL-DEFINED WITH CLEAR LOW-LEVEL CYCLONIC FLOW AROUND THE LOW CENTER. THE SYSTEM ALSO COINCIDES WITH A CUT-OFF AREA OF DEEP MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER...DRY AIR AND DUST SURROUND THE WAVE LIMITING MOST DEEP CONVECTION. ONLY SOME WEAK ISOLATED CONVECTION IS FROM 22N-24N BETWEEN 43W-47W. TROPICAL WAVE...REMNANTS OF T.D. SEVEN...IS MOVING W AT 20 KT THROUGH THE CENTRAL CARIBBEAN FROM 19N72W TO 11N76W. SATELLITE IMAGERY ALONG WITH SURFACE OBSERVATIONS AND A RECENT ASCAT SCATTEROMETER PASS 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 15N-19N BETWEEN 70W-77W INCLUDING MUCH OF SOUTHERN HISPANIOLA. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF SENEGAL AT 14N17W WHERE IT CONTINUES ACROSS ATLC WATERS ALONG 9N25W 9N37W. THE ITCZ BEGINS AT 9N37W AND CONTINUES ALONG 11N48W TO 10N64W. BESIDES CONVECTION ASSOCIATED WITH TROPICAL WAVES...SCATTERED MODERATE CONVECTION IS FROM 9N-12N BETWEEN 48W-54W. ...DISCUSSION... GULF OF MEXICO... WEAK SURFACE RIDGING COVERS THE MAJORITY OF THE GULF OF MEXICO TODAY EXTENDING FROM THE CENTRAL ATLC. SURFACE WINDS ARE LIGHT AND ANTI-CYCLONIC AROUND THE RIDGE. THE SURFACE RIDGE IS ALSO SUPPORTING MOSTLY FAIR WEATHER. IT IS SUPPORTED BY AN UPPER LEVEL RIDGE CENTERED OVER THE NW BAHAMAS. HOWEVER...AN UPPER LEVEL TROUGH OVER CENTRAL MEXICO IS HELPING SUPPORT A LARGE CLUSTER OF STRONG SHOWERS/THUNDERSTORMS IN THE SW GULF FROM 20N-24N BETWEEN 93W-97W. A BROAD UPPER TROUGH MOVING INTO THE EASTERN CONUS IS ALSO SUPPORTING A WEAK STATIONARY FRONT ALONG THE FLORIDA PANHANDLE. A FEW SHOWERS HAVE POPPED UP S OF THE AXIS AS WELL AS DOWN THE FLORIDA PENINSULA. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS. CARIBBEAN SEA... DRY AIR ALOFT COVERS THE WESTERN CARIBBEAN AROUND AN THE WEST SIDE OF AN INVERTED UPPER LEVEL TROUGH ALONG 79W. THE DRY AIR IS SUPPORTING MOSTLY CLEAR SKIES W OF 77W. STRONG SHOWERS/THUNDERSTORMS ARE IN THE EXTREME SW CARIBBEAN ALONG THE MONSOON TROUGH THAT EXTENDS FROM NORTHERN PANAMA AT 10N82W TO NORTHERN COLOMBIA AT 10N76W. THE CENTRAL CARIBBEAN IS IMPACTED BY AN ACTIVE TROPICAL WAVE THAT EXTENDS FROM HISPANIOLA TO NORTHERN COLOMBIA. IS IT SUPPORTING A LARGE AREA OF SHOWERS/THUNDERSTORMS FROM 14N-19N BETWEEN 70W-77W. SEE TROPICAL WAVE SECTION ABOVE FOR MORE DETAILS. THE WAVE LIES ON THE DIFFLUENT SIDE OF THE UPPER LEVEL TROUGH ALONG 79W...WHICH MAY BE HELPING ENHANCE SOME OF THE ACTIVITY NEAR THE WAVE. THE EASTERN CARIBBEAN IS NOW MOSTLY CLEAR DUE TO DRY AIR MOVING INTO THE AREA FROM THE TROPICAL ATLC AROUND AN UPPER LEVEL RIDGE OVER THE CENTRAL ATLC. EXPECT THE WAVE TO MOVE WESTWARD DRAWING MOISTURE WITH IT. ATLANTIC OCEAN... AN UPPER LEVEL RIDGE COVERS THE W ATLC SUPPORTING A WEAK SURFACE RIDGE. HOWEVER...AN UPPER LEVEL SHORTWAVE TROUGH TO THE N ALONG 70W IS SUPPORTING SHOWERS/THUNDERSTORMS FROM 28N-31N BETWEEN 67W-73W. A WEAK SURFACE TROUGH IS ALSO ALONG 31N75W TO 29N79W SUPPORTING A FEW ISOLATED SHOWERS NEAR THE AXIS. TO THE EAST...AN UPPER LEVEL LOW IS CENTERED NEAR 30N61W SUPPORTING A FEW ISOLATED SHOWERS N OF 29N BETWEEN 55W-61W. AN UPPER LEVEL RIDGE IS TO THE E CENTERED NEAR 30N48W SUPPORTING A 1025 MB HIGH NEAR 33N43W...WHICH IS PROVIDING SURFACE RIDGING AND FAIR WEATHER ACROSS THE REMAINDER OF THE ATLC...BESIDES NEAR TROPICAL WAVES. VISIBLE SATELLITE IMAGERY INDICATES THAT AN AREA OF DUST EXTENDS FROM THE COAST OF AFRICA AROUND BOTH TROPICAL WAVES IN THE TROPICAL ATLC. THE DRY AIR MASS IS LIMITING CONVECTION NEAR THE TROPICAL WAVES. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON