000 AXNT20 KNHC 112352 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN JUL 11 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC... ...TROPICAL WAVES... TROPICAL WAVE HAS MOVED OFF W AFRICA ALONG 17W/18W S OF 17N MOVING W 10-15 KT. BROAD MID LEVEL CYCLONIC ROTATION IS OBSERVED ALONG THE WAVE AXIS NEAR 11N ON SATELLITE IMAGERY. WAVE IS EMBEDDED WITHIN A MOISTURE MAXIMUM AS INDICATED ON THE TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/STRONG CONVECTION IS FROM 12N-15N E OF 19W TO INLAND OVER W AFRICA. TROPICAL WAVE IS ALONG 38W/39W S OF 16N MOVING W NEAR 15 KT. WAVE IS EMBEDDED WITHIN A LARGE AREA OF DRY SAHARAN AIR AND DUST PARTIALLY MASKING THE SATELLITE SIGNATURE AND SUPPRESSING ANY SHOWER ACTIVITY/CONVECTION. TROPICAL WAVE IN THE CENTRAL CARIBBEAN IS ALONG 75W S OF 19N MOVING W NEAR 20 KT. WAVE IS AT THE TRAILING EDGE A BROAD AREA OF DEEP LAYER MOISTURE THAT COVERS THE CARIBBEAN W OF 76W AS INDICATED ON THE TOTAL PRECIPITABLE WATER IMAGERY AND AT TOWARD THE LEADING EDGE OF THE LARGE AREA OF DRY SAHARAN AIR AND DUST THAT COVERS THE TROPICAL ATLC THUS LIMITING THE SHOWER ACTIVITY/ CONVECTION. TROPICAL WAVE IS ALONG 84W S OF 19N MOVING W 15-20 KT. WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP LAYER MOISTURE THAT COVERS MOST OF THE CARIBBEAN AS INDICATED ON THE TOTAL PRECIPITABLE WATER IMAGERY. LARGE AREA OF SCATTERED SHOWERS/THUNDERSTORMS ARE FROM 11N-18N W OF 82W TO INLAND OVER CENTRAL AMERICA AND THE YUCATAN PENINSULA ENHANCED BY AN UPPER RIDGE OVER THE W CARIBBEAN. THE TROPICAL WAVE OVER THE S GULF OF MEXICO IS NOW ANALYZED AS A SURFACE TROUGH. SEE GULF OF MEXICO BELOW. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 11N14W 6N27W 9N41W 8N47W 9N55W 8N63W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 75 NM OF LINE FROM 9N14W TO 5N28W. SMALL CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 2N-8N BETWEEN 35W-46W. ...DISCUSSION... GULF OF MEXICO... THE TROPICAL WAVE THAT WAS IN THE S GULF IS NOW A SURFACE TROUGH THAT EXTENDS FROM 20N96W SE ACROSS S MEXICO THROUGH THE ISTHMUS OF TEHUANTEPEC. AN UPPER RIDGE IS ANCHORED OVER THE YUCATAN PENINSULA NEAR 18N89W COVERING THE S GULF S OF 23N WITH A SECOND UPPER RIDGE COVERING THE N GULF ANCHORED OVER CENTRAL TEXAS EXTENDING AN AXIS ALONG THE N GULF COAST ACROSS CENTRAL FLORIDA INTO THE FAR W ATLC OVER LAKE OKEECHOBEE. A SURFACE RIDGE EXTENDS FROM THE W ATLC ACROSS S FLORIDA OVER MUCH OF THE GULF WITH A 1019 MB HIGH NEAR 26N87W. A SURFACE TROUGH IS ACROSS NE FLORIDA FROM JACKSONVILLE INTO THE NE GULF TO NEAR 29N86W GENERATING SCATTERED SHOWERS/THUNDERSTORMS INLAND OVER FLORIDA N OF LAKE OKEECHOBEE AND FROM THE FLORIDA PANHANDLE TO SE LOUISIANA. THIS SCENARIO IS LEAVING THE GULF UNDER MOSTLY CLEAR SKIES THIS EVENING. CARIBBEAN SEA... AN UPPER RIDGE IS ANCHORED OVER THE YUCATAN PENINSULA NEAR 18N89W COVERING THE W CARIBBEAN W OF 80W AND IS ENHANCING THE ACTIVITY ASSOCIATED WITH THE TROPICAL WAVE ALONG 84W. AN UPPER LOW IS OVER THE CENTRAL CARIBBEAN NEAR 17N75W. THE ITCZ EXTENDS ACROSS PANAMA INTO THE E PACIFIC REGION AND COUPLED WITH THE UPPER LOW OVER THE CENTRAL CARIBBEAN IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 13N FROM 72W-82W. AFTERNOON HEATING IS DEVELOPING THUNDERSTORMS INLAND OVER HISPANIOLA... CUBA...AND JAMAICA WHILE THE NORTHERLY FLOW ALOFT IS FORCING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS INTO THE CARIBBEAN WATERS WITHIN 60 NM ALONG THE SOUTHERN COASTLINES. A SECOND UPPER RIDGE IS OVER THE FAR E CARIBBEAN S OF 17N E OF 67W AND IS ENHANCING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS S OF 15N BETWEEN THE WINDWARD ISLANDS AND 66W LEAVING THE REMAINDER OF THE CARIBBEAN UNDER MOSTLY CLEAR SKIES THIS EVENING. VISIBLE SATELLITE IMAGERY INDICATED THAT A LARGE AREA OF DRY SAHARAN AIR AND DUST COVERS THE CARIBBEAN E OF 76W. ATLANTIC OCEAN... AN UPPER RIDGE EXTENDS FROM THE N GULF OF MEXICO ACROSS CENTRAL FLORIDA INTO THE FAR W ATLC TO NEAR 27N76W. THERE IS STATIONARY FRONT N OF THE DISCUSSION AREA WITH A SURFACE TROUGH EXTENDING FROM NE FLORIDA INTO THE GULF OF MEXICO WITH A SEABREEZE SURFACE TROUGH EXTENDING FROM 29N79W TO INLAND OVER S FLORIDA NEAR WEST PALM BEACH. SCATTERED SHOWERS/THUNDERSTORMS ARE N OF A LINE FROM NEAR MELBOURNE FLORIDA TO BEYOND 32N75W. A WEAKER SURFACE TROUGH IS JUST TO THE E EXTENDING FROM 31N74W ACROSS THE N BAHAMA ISLANDS TO 24N79W. A BROAD UPPER TROUGH IS IN THE CENTRAL ATLC EXTENDING THROUGH 32N57W TO 18N61W GENERATING ISOLATED SHOWERS/ THUNDERSTORMS FROM 21N-28N BETWEEN 66W-73W. A SURFACE RIDGE DOMINATES DOMINATES THE REMAINDER OF THE ATLC E OF 70W ANCHORED BY A 1030 MB HIGH OVER 900 NM ENE OF BERMUDA AND THEN NARROWS OVER THE REMAINDER OF THE W ATLC INTO THE GULF OF MEXICO OVER S FLORIDA. THE REMAINDER OF THE CENTRAL ATLC AND INTO THE E ATLC IS UNDER STRONG SUBSIDENCE AND DRY STABLE AIR ALOFT LEAVING THE AREA UNDER FAIR WEATHER THIS EVENING. VISIBLE SATELLITE IMAGERY INDICATED THAT A LARGE AREA OF DRY SAHARAN AIR AND DUST COVERS MOST OF THE TROPICAL ATLC ACROSS THE LESSER ANTILLES INTO THE CARIBBEAN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW