000 AXNT20 KNHC 200005 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN SEP 19 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 2345 UTC. ...SPECIAL FEATURES... HURRICANE IGOR IS CENTERED NEAR 31.9N 65.7W AT 20/0000 UTC OR ABOUT 60 MI WSW OF BERMUDA MOVING NNE AT 12 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 953 MB. MAXIMUM SUSTAINED WIND SPEED IS 65 KT WITH GUSTS TO 85 KT. IGOR REMAINS LARGE AND TROPICAL STORM CONDITIONS ARE ALREADY IMPACTING BERMUDA. THE CENTER WILL PASS NEAR OR OVER BERMUDA OVER THE NEXT HOUR OR SO. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. NUMEROUS MODERATE TO ISOLATED STRONG CONVECTION IS FROM 31N-36N BETWEEN 63W-69W. TROPICAL STORM JULIA IS CENTERED NEAR 34.8N 49.7W AT 19/2100 UTC OR ABOUT 1280 MI W OF THE AZORES MOVING NE AT 12 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1001 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. WEAKENING IS EXPECTED AS JULIA MOVES ENE OVER COOLER WATERS AND CONTINUES TO EXPERIENCE WIND SHEAR FROM THE OUTFLOW OF HURRICANE IGOR OVER THE NEXT SEVERAL DAYS. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. NUMEROUS MODERATE TO ISOLATED STRONG CONVECTION IS FROM 32N-37N BETWEEN 41W-50W. AN AREA OF LOW PRESSURE IS LOCATED WSW OF THE CAPE VERDE ISLANDS CONCENTRATED NEAR A 1008 MB LOW NEAR 15N31W MOVING W NEAR 5-10 KT. AN AREA OF DEEP LAYERED MOISTURE SURROUNDS THE SURFACE LOW NOTED ON TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 11N-18N BETWEEN 84W AND 35W. ENVIRONMENTAL CONDITIONS ARE FAVORABLE FOR A TROPICAL DEPRESSION TO FORM DURING THE NEXT DAY OR SO AS THIS SYSTEM MOVES SLOWLY NORTHWESTWARD. THERE IS A HIGH CHANCE OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. ...ITCZ... A MONSOONAL TROUGH IS ANALYZED OFF THE W AFRICAN COAST ALONG 11N15W 9N18W TO 11N24W...RESUMING OVER THE CAPE VERDE ISLANDS NEAR 18N24W SW ALONG 14N32W 11N36W TO 11N43W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 5N TO 11N BETWEEN THE COAST OF AFRICA AND 25W. SIMILAR CONVECTION IS FROM 10N TO 18N BETWEEN 28W AND 42W. A SURFACE LOW IS EMBEDDED IN THIS AREA OF MONSOONAL TROUGHINESS NEAR 15N31W. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. A TRADITIONAL SURFACE TROUGH IS ANALYZED FROM 13N49W TO 5N54W. SCATTERED MODERATE CONVECTION IS WITHIN 80 NM ON EITHER SIDE OF THE TROUGH AXIS N OF 9N. ...DISCUSSION... GULF OF MEXICO... A MID/UPPER LEVEL RIDGE OF HIGH PRESSURE IS OVER THE GULF WITH ANTI-CYCLONIC FLOW ALOFT CENTERED OVER THE CENTRAL GULF. A WEAK SUBTROPICAL JET STREAK MOVES AROUND THE NORTHERN PORTION OF THE ANTI-CYCLONIC FLOW COVERING THE NORTHERN HALF OF THE GULF. THE REAR-RIGHT QUADRANT OF THIS UPPER LEVEL FEATURE ALONG WITH DEEP LAYER MOISTURE AND INSTABILITY ACROSS THE NW GULF SUPPORT A NEARLY STATIONARY SURFACE TROUGH THAT LINES UP 75 NM OFF THE TEXAS AND MEXICO COAST FROM 27N95W SOUTHWARD TO 23N96W. THE SYSTEM IS PRODUCING SCATTERED HEAVY SHOWERS AND THUNDERSTORMS ACROSS THE TEXAS COASTAL WATERS N OF 25N W OF 92W. COMPUTER MODELS SUGGEST THIS AREA OF CONVECTION WILL LINGER THROUGH THE MIDDLE OF NEXT WEEK. FAIR WEATHER CONDITIONS ARE ELSEWHERE ACROSS THE BASIN. CARIBBEAN SEA... TOTAL PRECIPITABLE WATER IMAGERY DISPLAYS A STREAM OF DEEP LAYER MONSOONAL MOISTURE MOVING N ACROSS THE EASTERN CARIBBEAN. THE MOISTURE FLOW IS DUE TO THE LARGE SCALE CYCLONIC WIND FIELD LEFT FROM HURRICANE IGOR. THIS SCENARIO IS GENERATING SCATTERED SHOWERS AND THUNDERSTORMS E OF 67W INCLUDING THE LEEWARD ISLANDS AND PUERTO RICO AS NOTED BY SATELLITE DATA AND DOPPLER RADAR IMAGERY. COMPUTER MODELS SUGGEST THE CONVECTION IS THIS REGION WILL LINGER OVER THE NEXT 24 TO 36 HOURS. SCATTERED MODERATE CONVECTION IS ALSO OVER THE SOUTH CENTRAL AND SW CARIBBEAN S OF 14N W OF 70W DUE TO CLOSE PROXIMITY TO MONSOONAL TROUGH EXTENDING ACROSS THIS REGION. FAIR WEATHER CONDITIONS WITH A FEW ISOLATED SHOWERS ARE OBSERVED ELSEWHERE ACROSS THE BASIN...DUE TO A DRY AND STABLE AIRMASS ALOFT CAPTURED ON WATER VAPOR IMAGERY. ATLANTIC OCEAN... STRONG SUBSIDENCE OF AIR ALOFT IS NOTED ON WATER VAPOR IMAGERY MOVING S ACROSS THE WESTERN ATLC W OF 70W BRINGING A VERY DRY AND STABLE AIRMASS TO THIS REGION. HURRICANE IGOR IS TO THE EAST OF THIS DRY AIRMASS...CURRENTLY IMPACTING THE ISLAND OF BERMUDA. TROPICAL STORM JULIA IS TO THE ENE OF IGOR OVER OPEN WATERS. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS ON BOTH SYSTEMS. THE LARGE SCALE CYCLONIC WIND FIELD FROM HURRICANE IGOR IS DRAWING A STREAM OF DEEP LAYER MONSOONAL MOISTURE NORTH ACROSS THE EASTERN CARIBBEAN AND THE LESSER ANTILLES INTO THE ATLC. ALTHOUGH THE HEAVIEST ACTIVITY IS CURRENTLY OVER THE E CARIBBEAN...SCATTERED SHOWERS AND THUNDERSTORMS ARE FROM 18N TO 22N BETWEEN 60W AND 67W. SURFACE RIDGING IS ELSEWHERE ACROSS THE AREA OF DISCUSSION E OF 60W N OF 18N SUPPORTED BY A BROAD 1022 MB HIGH SW OF THE AZORES NEAR 35N36W. A LARGE AREA OF AFRICAN DUST FROM THE SAHARA REGION IS NOTED ON SATELLITE IMAGERY...COVERING MOST OF THE EASTERN ATLC FROM 14N TO NORTH OF THE AREA OF DISCUSSION BETWEEN THE COAST OF AFRICA AND 50W. THIS SAHARAN AIR LAYER...ALONG WITH THE SUB-TROPICAL HIGH ARE KEEPING FAIR WEATHER CONDITIONS IN THIS REGION. 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