000 AXNT20 KNHC 091139 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU SEP 09 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...SPECIAL FEATURES... TROPICAL STORM IGOR IS CENTERED NEAR 14.1N 24.2W AT 09/1200 UTC OR ABOUT 50 NM S OF THE SOUTHERNMOST CAPE VERDE ISLANDS NEAR STATIONARY. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. PLEASE SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC AND THE FULL FORECAST AND ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. IGOR REMAINS IN A SHEAR ENVIRONMENT WITH THE CONVECTION DISPLACED TO THE W OF THE EXPOSED LOW LEVEL CENTER. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 12N-17N BETWEEN 25W-30W. ...ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 10N26W 9N40W 10N52W 12N57W THEN RESUMES IN THE S CARIBBEAN NEAR 12N65W 12N73W 10N78W ACROSS COSTA RICA INTO THE E PACIFIC REGION NEAR 10N84W. A 1009 MB LOW IS EMBEDDED WITHIN THE ITCZ NEAR 12N60W WITH A SURFACE TROUGH ALONG 60W BETWEEN 10N-15N. CLUSTERS OF SCATTERED MODERATE/ ISOLATED STRONG CONVECTION ARE FROM 5N-10N BETWEEN 35W-46W... S OF 13N TO INLAND OVER SOUTH AMERICA BETWEEN 51W-55W... AND S OF 13N TO THE COAST OF SOUTH AMERICA BETWEEN 56W-64W INCLUDING THE WINDWARD ISLANDS/TRINIDADA AND TOBAGO. ...DISCUSSION... GULF OF MEXICO... THE BROAD UPPER RIDGE ANCHORED ALONG THE LOUISIANA/TEXAS COAST EXTENDS A RIDGE AXIS E ALONG 30N ACROSS THE N GULF COAST STATES INTO THE W ATLC COVERING THE GULF WATERS. A SURFACE TROUGH EXTENDS FROM NEAR WEST PALM BEACH FLORIDA SW ACROSS THE PENINSULA TO EVERGLADES CITY INTO THE GULF ALONG 24N84W TO THE YUCATAN CHANNEL NEAR 21N86W. THE UPPER LOW IN THE NW CARIBBEAN COMBINED WITH THE SURFACE TROUGH ARE GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 25N E OF 82W INTO THE W ATLC AND OVER CUBA INCLUDING THE FLORIDA KEYS. THIS IS LEAVING THE REMAINDER OF THE GULF UNDER MOSTLY CLEAR SKIES THIS MORNING WITH THE EXCEPTION OF SOME ISOLATED LOW LEVEL SHOWERS DOTTING THE AREA E OF 90W. CARIBBEAN SEA... AN UPPER LOW REMAINS CENTERED IN THE NW CARIBBEAN IS CENTERED S OF CUBA NEAR 20N85W EXTENDING OVER THE NW CARIBBEAN E OF 82W AND N TO OVER CUBA AND THE YUCATAN CHANNEL CLUSTERS OF GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 19N TO OVER CUBA BETWEEN 80W-87W. THE BROAD UPPER RIDGE ANCHORED IN THE CENTRAL ATLC EXTENDS AN AXIS ALONG 20N TO E CUBA NEAR 77W DRAWING DRY STABLE AIR OVER THE NE CARIBBEAN N OF 15N E OF 69W. BENEATH IS UPPER RIDGE IS THE REMNANT MOISTURE OF A SURFACE TROUGH COVERING THE AREA WITH CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 15N-20N BETWEEN 69W-77W INCLUDING PORTIONS OF HISPANIOLA AND JAMAICA. THE ITCZ CROSSING THE S CARIBBEAN FROM THE WINDWARD ISLANDS TO COSTA RICA IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 13N BETWEEN 68W-80W INCLUDING COLOMBIA AND PANAMA. ATLANTIC OCEAN... THE UPPER LOW IN THE NW CARIBBEAN IS ENHANCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 26N TO OVER CUBA BETWEEN 77W-82W. DOPPLER RADAR INDICATES THE ACTIVITY IS CROSSING THE FLORIDA KEYS BUT IS DISSIPATING AS IT APPROACHES THE FLORIDA MAINLAND. THIS ACTIVITY COULD MOVE ONSHORE OVER S FLORIDA LATER THIS MORNING. THE BROAD UPPER RIDGE THAT COVERS THE GULF OF MEXICO EXTENDS AN AXIS INTO THE W ATLC ALONG 30N COVERING THE W ATLC W OF 65W. AN UPPER LEVEL TROUGH EXTENDS INTO THE W/CENTRAL ATLC NEAR 32N56W SW TO 26N64W BECOMING A SHEAR AXIS TO THE BAHAMAS NEAR 23N75W. STRONG SUBSIDENCE AND DRY STABLE AIR COVERS THE W ATLC 24N-29N BETWEEN 65W-75W AND THE CENTRAL ATLC FROM 13N-28N W OF 40W TO THE UPPER TROUGH. A WEAK SURFACE RIDGE DOMINATES THE W ATLC N OF 25N ANCHORED BY A 1018 MB HIGH NEAR 29N68W. A WEAK UPPER LOW IS CENTERED IN THE CENTRAL ATLC NEAR 28N47W GENERATING ISOLATED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 30N-32N BETWEEN 44W-47W. AN E/W UPPER RIDGE IS ANCHORED W AFRICA EXTENDING AN AXIS W ALONG 21N INTO THE E TROPICAL ATLC TO 40W. BENEATH IS THE T.S. IGOR IN THE SPECIAL FEATURES ABOVE. A 1010 MB SURFACE LOW IS ALSO BENEATH THE UPPER RIDGE CENTERED NEAR 21N38W GENERATING ISOLATED SHOWERS FROM 22N-27N BETWEEN 37W-42W. A SURFACE RIDGE COVERS THE REMAINDER OF THE E ATLC N OF 25N E OF 45W ANCHORED BY A 1024 MB HIGH E OF THE AZORES. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW