000 AXNT20 KNHC 130516 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT TUE JUL 13 2010 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0430 UTC... ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 19N28W TO 8N29W MOVING W NEAR 20 KT. THE WAVE LIES AHEAD OF A MAXIMUM IN DEEP LAYER MOISTURE. BROAD CYCLONIC FLOW IS ALSO ABOUT THE WAVE AXIS EVIDENT IN TOTAL SATELLITE IMAGERY. LAST VISIBLE SATELLITE IMAGES OF THE DAY ALSO INDICATE AN AREA OF DUST ASSOCIATED WITH A DRY SAHARAN AIR LAYER IS ACROSS MUCH OF THE TROPICAL ATLC SUPPRESSING CONVECTION NEAR THE WAVE. HOWEVER...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS NEAR THE ITCZ FROM 6N-11N BETWEEN 26W-33W. TROPICAL WAVE IS ALONG 48W S OF 15N MOVING W NEAR 20 KT. WAVE IS SUPPRESSED AND MASKED DUE TO A DRY SAHARAN AIR LAYER ACROSS THE TROPICAL ATLC KEEPING CONVECTION TO A MINIMUM AND RESTRICTED TO THE ITCZ. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 6N-10N BETWEEN 49W-52W. TROPICAL WAVE IS ALONG 86W/87W S OF 20N MOVING W NEAR 20 KT. WAVE COINCIDES WITH A MAXIMUM IN DEEP LAYER MOISTURE THAT IS ACROSS THE FAR WRN CARIBBEAN AND INTO THE E PACIFIC. THE WAVE ALSO LIES AHEAD OF A DRY SAHARAN AIR LAYER AND A LARGE AREA OF DUST ACROSS THE TROPICAL ATLC AND INTO THE ERN AND CENTRAL CARIBBEAN. HOWEVER...DUE TO A DIFFLUENT ZONE ALOFT NUMEROUS STRONG CONVECTION IS ACROSS NRN CENTRAL AMERICA FROM 11N-17N BETWEEN 88W-93W. SCATTERED MODERATE CONVECTION IS ALSO FROM 8N-17N BETWEEN 80W-87W. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 13N15W 10N29W 10N47W 8N64W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 8N-11N BETWEEN 10W-19W. SIMILAR ACTIVITY IS FROM 4N-8N BETWEEN 33W-38W...AND FROM EQ-12N BETWEEN 52W-60W. ...DISCUSSION... GULF OF MEXICO... A DRY AND STABLE AIRMASS LIES ACROSS MUCH OF THE GULF OF MEXICO AROUND AN UPPER LEVEL RIDGE CENTERED OVER LOUISIANA NEAR 30N92W MAINTAINING FAIR CONDITIONS ACROSS THE BASIN. A FEW SHOWERS/THUNDERSTORMS ARE IN THE FAR SW GULF AROUND AN UPPER LEVEL LOW IN THE BAY OF CAMPECHE NEAR 21N94W. SOME OF THIS ACTIVITY MAY BE INFLUENCED BY A TROPICAL WAVE ALONG 95W IN THE E PACIFIC. AT THE SURFACE...RIDGING DOMINATES ANCHORED BY A 1015 MB HIGH CENTERED W OF FLORIDA NEAR 26N85W. LIGHT ANTI-CYCLONIC FLOW IS AROUND THE SURFACE RIDGE WITH STRONGER SLY WINDS REACHING UP TO 20 KT ALONG THE TEXAS COASTLINE. A WEAK SURFACE TROUGH EXTENDS DOWN THE FLORIDA PENINSULA...THE RESULT OF SEABREEZE CONVERGENCE...ENHANCING A FEW ISOLATED SHOWERS W OF THE FLORIDA KEYS. EXPECT SURFACE RIDGING TO REMAIN ACROSS THE BASIN ALONG WITH DRY AIR AND MOSTLY FAIR CONDITIONS. CARIBBEAN SEA... A TROPICAL WAVE ALONG 86W/87W IN THE FAR WRN CARIBBEAN ACROSS CENTRAL AMERICA CONTINUES BRINGING ENHANCED MOISTURE TO THIS PORTION OF THE AREA SUPPORTING SHOWERS/THUNDERSTORMS ACROSS MUCH OF CENTRAL AMERICA AND THE COASTAL WATERS. SEE TROPICAL WAVE SECTION ABOVE FOR MORE DETAILS. SOME OF THIS ACTIVITY IS ENHANCED BY DIFFLUENCE ALOFT BETWEEN AN UPPER LEVEL RIDGE CENTERED OVER THE YUCATAN PENINSULA AND NRN CENTRAL AMERICA AND AN UPPER LEVEL TROUGH COVERING THE REMAINDER OF THE CARIBBEAN WITH A HORIZONTAL AXIS EXTENDING FROM THE LESSER ANTILLES TO NEAR 14N79W. THIS UPPER LEVEL TROUGH IS ACCOMPANIED BY DRY AIR EXTENDING FROM THE TROPICAL ATLC. SEVERAL STATIONS ARE ALSO INDICATING THE PRESENCE OF DUST. DUE TO THIS STABLE AIR MASS...MUCH OF THE ERN AND CENTRAL CARIBBEAN IS EXPERIENCING GENERALLY FAIR WEATHER. HOWEVER...A FEW LINGERING SHOWERS ARE NOTED ACROSS CUBA AND HISPANIOLA. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO IN THE SW CARIBBEAN S OF 12N DUE TO SURFACE CONVERGENCE NEAR AN EXTENSION OF THE E PACIFIC ITCZ FROM COSTA RICA TO NRN COLOMBIA. EXPECT FAIR CONDITIONS TO REMAIN ACROSS MUCH OF THE BASIN UNDER THE PRESENCE OF DRY AIR. ATLANTIC OCEAN... A SHORTWAVE UPPER LEVEL TROUGH EXTENDS DOWN THE ERN SEABOARD SUPPORTING ISOLATED SHOWERS/THUNDERSTORMS N OF 29N BETWEEN 77W-81W. A SECOND SHORTWAVE UPPER LEVEL TROUGH EXTENDS OVER THE SE BAHAMAS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS FROM 21N-24N BETWEEN 75W-79W...AND POSSIBLE ISOLATED SHOWERS/THUNDERSTORMS ACROSS CUBA AND HISPANIOLA. A LINE OF SHOWERS IS ALSO NOTED OFF THE SE COAST OF FLORIDA DUE TO WIND CONVERGENCE ALONG THE COAST. UPPER LEVEL RIDGING IS BETWEEN THESE TWO UPPER SHORTWAVES. AT THE SURFACE...RIDGING DOMINATES THE ENTIRE BASIN ANCHORED BY A 1033 MB HIGH CENTERED NEAR 41N45W. A DRY SAHARAN AIR LAYER ACCOMPANIED BY DUST COVERS MUCH OF THE TROPICAL ATLC KEEPING CONDITIONS FAIR. ALOFT...AN UPPER LEVEL TROUGH IS BETWEEN 59W-67W...WITH UPPER RIDGING BETWEEN 50W-59W...FOLLOWED BY ANOTHER UPPER LEVEL TROUGH BETWEEN 36W-50W. AN UPPER LEVEL RIDGE COVERS THE FAR ERN ATLC CENTERED W OF THE CANARY ISLANDS NEAR 26N25W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON