000 AXNT20 KNHC 170008 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU SEP 16 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 KARL IS CENTERED NEAR 19.7N 94.1W AT 17/0000 UTC OR ABOUT 140 MI...225 KM ENE OF VERACRUZ MEXICO...OR ABOUT 235 MI...375 KM ESE OF TUXPAN MEXICO...MOVING W AT 10 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 971 MB. MAXIMUM SUSTAINED WIND SPEED IS 70 KT WITH GUSTS TO 85 KT. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT3/WTNT33 AND THE FULL FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. NUMEROUS STRONG CONVECTION IS FROM 17N-21N BETWEEN 92W-97W. THE OUTER BANDS OF MODERATE TO STRONG CONVECTION COVER THE REMAINDER OF THE AREA INCLUDING THE CENTRAL AND SE GULF OF MEXICO AND THE NW CARIBBEAN. THESE RAINS COULD CAUSE LIFE-THREATENING FLASH FLOODS AND MUD SLIDES...ESPECIALLY IN AREAS OF MOUNTAINOUS TERRAIN. THE OUTER BANDS OF MODERATE TO STRONG CONVECTION COVER THE REMAINDER OF THE AREA INCLUDING THE CENTRAL AND SE GULF OF MEXICO AND THE NW CARIBBEAN. HURRICANE IGOR IS CENTERED NEAR 21.7N 58.1W AT 16/2100 UTC MOVING NW AT 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 940 MB. MAXIMUM SUSTAINED WIND SPEED IS 110 KT WITH GUSTS TO 135 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. NUMEROUS STRONG CONVECTION IS FROM 18N-23N BETWEEN 56W-60W. MODERATE CONVECTION COVERS THE REMAINDER OF THE AREA WITHIN 260 NM FROM THE CENTER. SOME FLUCTUATIONS IN STRENGTH ARE POSSIBLE DURING THE NEXT OR TWO...BUT IGOR IS EXPECTED TO REMAIN A DANGEROUS HURRICANE. HURRICANE JULIA IS CENTERED NEAR 23.1N 41.1W AT 16/2100 UTC MOVING WNW AT 22 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 981 MB. MAXIMUM SUSTAINED WIND SPEED IS 75 KT WITH GUSTS TO 90 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. SATELLITE PRESENTATION OF JULIA HAS CONTINUED TO DETERIORATE OVER THE PAST FEW HOURS. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 21N-25N BETWEEN 40W-44W. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG THE COAST OF W AFRICA ALONG 18W S OF 17N MOVING W AT 10 KT. SATELLITE IMAGERY SHOWS CYCLONIC TURNING IN THE VICINITY OF THE WAVE N OF 12N. A DEEP LAYERED MOISTURE SURROUNDS THE WAVE NOTED ON TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 7N-14N BETWEEN THE COAST OF AFRICA AND 24W. HOWEVER...THE CONVECTION ASSOCIATED WITH THE WAVE IS EMBEDDED IN THE MONSOONAL TROUGH COVERING A LARGER AREA IN THE TROPICAL ATLC. ...ITCZ... THE ITCZ...OR PERHAPS BETTER DESCRIBED AS A MONSOONAL TROUGH BECAUSE OF THE CONVERGENCE OF NE AND SW SURFACE WINDS...REMAINS DISCONTINUOUS ACROSS THE ATLANTIC DUE TO THE LARGE SCALE WIND FIELD FROM HURRICANES IGOR AND JULIA. THE AXIS EXTENDS FROM 7N21W TO 10N28W...RESUMING NEAR 11N34N TO 10N45W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 5N TO 14N BETWEEN THE WEST COAST OF AFRICA AND 40W. SIMILAR CONVECTION IS FROM 6N TO 13N BETWEEN 40W AND 47W. ...DISCUSSION... GULF OF MEXICO... HURRICANE KARL IS THE MAIN FEATURE OF CONCERN OVER THE GULF OF MEXICO. CURRENTLY LOCATED OVER THE BAY OF CAMPECHE...THE OUTER BANDS FROM KARL SPREAD ACROSS MOST OF THE GULF PRODUCING SCATTERED SHOWERS AND THUNDERSTORMS...EXCEPT THE EXTREME NE BASIN N OF 27N E OF 86W. SHORT RANGE COMPUTER MODELS INDICATE THE CONVECTION ASSOCIATED WITH KARL WILL CONTINUE TO SPREAD ACROSS THE CENTRAL AND WESTERN BASIN THROUGHOUT THE NEXT FEW DAYS AND OVER THE WEEKEND. THE CLOSEST BANDS TO THE EYE OF THIS SYSTEM WILL BRING CONSIDERABLE RAINFALL AND WIND DAMAGE TO THE MEXICO REGION AS IT MAKES LANDFALL OVER THE NEXT FEW DAYS. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS REGARDING THIS SYSTEM. CARIBBEAN SEA... ALTHOUGH KARL IS CENTERED OVER THE BAY OF CAMPECHE...GULF OF MEXICO...THE OUTER BANDS FROM THIS SYSTEM CONTINUE TO SPREAD ACROSS THE FAR NW CARIBBEAN SEA N OF 18N W OF 80W...PRODUCING SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE AREA INCLUDING THE YUCATAN CHANNEL. THIS AREA OF CONVECTION IS EXPECTED TO MOVE OUT OF THE AREA BY FRIDAY NIGHT. AWAY FROM THIS AREA OF CONVECTION...FAIR WEATHER CONDITIONS ARE ELSEWHERE ACROSS THE BASIN E OF 80W...DUE TO DRY AIR AND STRONG SUBSIDENCE ALOFT NOTED ON WATER VAPOR IMAGERY. ATLANTIC OCEAN... HURRICANES IGOR AND JULIA TOGETHER WITH A NEW TROPICAL WAVE ARE THE PRIMARY SURFACE FEATURES OVER THE ATLANTIC. SEE SPECIAL FEATURES ABOVE FOR MORE INFORMATION REGARDING THESE TWO SYSTEMS. HAVING TWO HURRICANES SIMULTANEOUSLY IN THE ATLANTIC BASIN AND ONE IN THE GULF OF MEXICO IS NOT A COMMON OCCURRENCE EVEN FOR THE PEAK OF THE HURRICANE SEASON WHICH WE ARE IN. A LARGE AREA OF SAHARAN AIR ALOFT IS NOTED ON SATELLITE IMAGERY...COVERING MOST OF THE EASTERN ATLC FROM 14N TO 28N BETWEEN 33W AND THE COAST OF AFRICA. THE SAHARAN AIR LAYER...ALONG WITH THE EAST ATLC UPPER LEVEL RIDGE SUPPORTING THE SUB-TROPICAL 1027 MB HIGH LOCATED NEAR 39N30W...ARE KEEPING FAIR WEATHER CONDITIONS IN THIS REGION. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA