000 AXNT20 KNHC 091804 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1745 UTC. ...SPECIAL FEATURES... TROPICAL STORM IGOR IS CENTERED NEAR 15.5N 25.4W AT 09/1800 UTC OR ABOUT 65 NM NW OF BRAVA IN THE CAPE VERDE ISLANDS...MOVING NW AT 8 KT. 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 IS EMBEDDED WITHIN AN AREA OF DEEP LEVEL MOISTURE AS INDICATED ON TOTAL PRECIPITABLE WATER IMAGERY. THE SYSTEM REMAINS IN A SHEAR ENVIRONMENT WITH THE CONVECTION DISPLACED TO THE W OF THE EXPOSED LOW LEVEL CENTER. CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE FROM 12N-17N BETWEEN 25W-30W. A SURFACE TROUGH WITH A LOW LEVEL CIRCULATION EMBEDDED IN IT IS LOCATED SE OF THE WINDWARD ISLANDS ANALYZED FROM 15N59W CROSSING THE LOW CENTER NEAR 12N60W CONTINUING SOUTH TO ABOUT 9N61W. THIS SYSTEM IS EMBEDDED WITHIN A BROAD AREA OF DEEP LEVEL MOISTURE AS INDICATED ON TOTAL PRECIPITABLE WATER IMAGERY...MOST LIKELY RELATED TO MONSOONAL TROUGHINESS IN THIS GENERAL REGION. BROAD CYCLONIC TURNING IS EVIDENT ON VISIBLE IMAGERY. SCATTERED MODERATE TO STRONG CONVECTION IS S OF 15N BETWEEN 57W AND 63W. ENVIRONMENTAL CONDITIONS APPEAR FAVORABLE FOR SOME GRADUAL DEVELOPMENT AS THE LOW MOVES SLOWLY WESTWARD. THERE IS A MEDIUM CHANCE OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. ...TROPICAL WAVES... NO TROPICAL WAVES ARE OBSERVED OVER THE ATLANTIC ON THE 1200 UTC SURFACE ANALYSIS. ...ITCZ... THE ITCZ AXIS IS ANALYZED FROM 9N27W CONTINUING WESTWARD ALONG 7N36W 8N46W TO 10N56W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 80 NM ON EITHER SIDE OF THE ITCZ AXIS E OF 50W...WHILE SCATTERED STRONG CONVECTION IS OVER THE COASTAL WATERS OF GUYANA...SURINAME...AND FRENCH GUIANA S OF 12N W OF 50W INCLUDING NORTHERN PORTIONS OF EASTERN VENEZUELA AND GUYANA. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES THAT MOST OF THE GULF REMAINS UNDER THE INFLUENCE OF ANTI-CYCLONIC FLOW ALOFT PRODUCING RELATIVELY STABLE CONDITIONS ACROSS THE REGION...EXCEPT FOR THE NORTH CENTRAL GULF...WHERE A WEAK AREA OF SURFACE TROUGHINESS IS GENERATING ISOLATED SHOWERS N OF 25N BETWEEN 86W AND 91W. AN UPPER LEVEL LOW CURRENTLY OVER THE FAR NW CARIBBEAN SEA WILL CROSS THE NORTHERN YUCATAN PENINSULA AND ENTER THE SW GULF OVER THE NEXT 24 TO 36 HRS BRINGING WEAK CONVECTION. OTHERWISE...NO SIGNIFICANT CHANGES ARE EXPECTED DURING THE FORECAST PERIOD. CARIBBEAN SEA... AN UPPER LOW REMAINS CENTERED IN THE NW CARIBBEAN 120 NM EAST OF THE YUCATAN PENINSULA NEAR 20N86W...PRODUCING CLOUDINESS AND SCATTERED SHOWERS WEST OF 85W FROM 18N TO 21N. THIS UPPER FEATURE WILL CONTINUE TO MOVE WESTWARD AND WOULD LIKELY EXIT THE NW CARIBBEAN SEA OVER THE NEXT 12 HOURS. ELSEWHERE...THE REMNANT OF GASTON...WHICH IS NOW AN OPEN TROUGH...IS GENERATING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE NORTH CENTRAL CARIBBEAN NORTH OF 15N BETWEEN 72W AND 79W. A NEAR STATIONARY SURFACE TROUGH WITH A LOW CONNECTED TO IT NEAR 12N60W IS PRODUCING CLOUDINESS...SHOWERS...AND THUNDERSTORMS OVER THE FAR SOUTHEASTERN CARIBBEAN INCLUDING THE SOUTHERN WINDWARD ISLANDS SOUTH OF DOMINICA EAST OF 65W. COMPUTER MODEL GUIDANCE SUGGEST THE UNSTABLE WEATHER CONDITIONS WILL CONTINUE IN THIS REGION OVER THE NEXT 24 HOURS. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS REGARDING THIS SYSTEM. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE OVER THE SW BASIN OF 15N W OF 75W...ASSOCIATED WITH NEARBY CONVERGENCE IN THE VICINITY OF THE MONSOONAL TROUGH. COMPUTER MODELS SUGGEST THIS AREA OF CONVECTION WILL LINGER IN THIS REGION OVER THE NEXT 24 HOURS. MEANWHILE DRY STABLE AIR ALOFT CONTINUES TO INTRUDE THE NORTHEASTERN CARIBBEAN BRINGING MOSTLY STABLE ATMOSPHERIC CONDITIONS N OF 15N E OF 71W. ATLANTIC OCEAN... THE PRIMARY CONCERN CONTINUES TO BE TROPICAL STORM IGOR LOCATED ABOUT 65 NM NW OF BRAVA IN THE CAPE VERDE ISLANDS. FOR MORE DETAILS REGARDING THIS STORM...SEE SPECIAL FEATURES ABOVE. OTHERWISE...DRY STABLE AIR ALOFT COVERS THE REST OF THE DISCUSSION AREA PROVIDED BY STRONG MID/UPPER LEVEL RIDGE ESTABLISHED IN THE EASTERN ATLC SUPPORTING A SURFACE 1027 MB HIGH EAST OF THE AZORES NEAR 37N19W...WITH SURFACE RIDGING AXIS EXTENDING WSW ACROSS THE CENTRAL ATLANTIC TO NEAR 30N60W. A WEAK SURFACE TROUGH IS BENEATH THE UPPER RIDGE MOVING ACROSS THE CENTRAL ATLANTIC...ANALYZED FROM 23N40W TO 14N43W...GENERATING SCATTERED SHOWERS FROM 14N TO 28N BETWEEN 37W AND 45W. THIS SYSTEM WILL CONTINUE TO MOVE WESTWARD WITH CONVECTION OVER THE NEXT 24 HOURS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ SALMON/GARCIA