000 AXNT20 KNHC 111155 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT WED SEP 11 2013 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...SPECIAL FEATURES... TROPICAL STORM GABRIELLE IS CENTERED NEAR 32.4N 65.7W AT 11/1200 UTC OR ABOUT 46 NM W OF BERMUDA. THE SYSTEM IS NOW STATIONARY AND HAS AN ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT2/WTNT32 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. SCATTERED MODERATE CONVECTION IS WELL THE E OF THE LOW CENTER FROM 31N-33N BETWEEN 61W-63W. TROPICAL STORM HUMBERTO WAS UPGRADED TO HURRICANE AT 11/0900 UTC. HURRICANE HUMBERTO IS CENTERED NEAR 16.0N 28.9W AT 11/0900 UTC OR ABOUT 270 NM W-NW OF THE SOUTHERNMOST CAPE VERDE ISLANDS MOVING N-NW AT 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 992 MB. MAXIMUM SUSTAINED WIND SPEED IS 65 KT WITH GUSTS TO 80 KT. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT4/WTNT34 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. SCATTERED/NUMEROUS STRONG CONVECTION IS WITHIN 45 NM OF THE CENTER IN ALL QUADRANTS. SCATTERED MODERATE/STRONG CONVECTION COVERS THE REMAINDER OF THE AREA FROM 14N-19N BETWEEN 26W-31W. SCATTERED MODERATE CONVECTION IS FROM 12N-14N BETWEEN 26W-34W. A BROAD AREA OF LOW PRESSURE OVER THE NW CARIBBEAN IS PRODUCING A LARGE AREA OF DISORGANIZED SHOWERS AND THUNDERSTORMS. A SURFACE TROUGH EXTENDS FROM THE S GULF OF MEXICO NEAR 22N87W OVER THE E COAST OF THE YUCATAN PENINSULA ALONG 20N87W TO THE COAST OF HONDURAS NEAR 16N88W. THE SURFACE TROUGH SHOULD MOVE ACROSS THE YUCATAN TODAY AND ENTER THE BAY OF CAMPECHE ON THU. SOME DEVELOPMENT IS POSSIBLE AFTER THE SYSTEM EMERGES OVER WATER AND THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. LOCALLY HEAVY RAINS AND GUSTY WINDS ARE EXPECTED OVER BELIZE... GUATEMALA...AND THE YUCATAN PENINSULA DURING THE NEXT DAY OR TWO. SCATTERED/NUMEROUS STRONG CONVECTION IS INLAND AND WITHIN 45 NM ALONG THE COAST OF BELIZE. SCATTERED MODERATE/STRONG CONVECTION COVERS THE REMAINDER OF THE AREA FROM 16N-20N W OF 85W TO INLAND OVER THE YUCATAN. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS DOT THE REMAINDER OF THE NW CARIBBEAN FROM 16N-22N W OF 80W TO INLAND OVER CUBA...THE YUCATAN PENINSULA...AND CENTRAL AMERICA. ...TROPICAL WAVES... NONE. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 14N17W TO 13N20W THEN RESUMES SW OF HURRICANE HUMBERTO NEAR 13N35W TO 9N45W WHERE THE ITCZ BEGINS AND CONTINUES INTO SOUTH AMERICA NEAR 7N59W. THE MONSOON TROUGH CONTINUES TO BE DISRUPTED BY HURRICANE HUMBERTO. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 75 NM LINE FROM 4N13W TO 10N16W AND WITHIN 60 NM OF LINE FROM 8N33W TO 6N42W. A SURFACE TROUGH IS N OF THE ITCZ EXTENDING FROM 17N46W 18N53W TO 20N57W. THE LOW PREVIOUSLY ASSOCIATED WITH THIS TROUGH IS NO LONGER DISCERNIBLE. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 150 NM S OF THE TROUGH W OF 51W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 120 NM EITHER SIDE OF THE REMAINDER OF THE TROUGH. ...DISCUSSION... GULF OF MEXICO... THE SHORTWAVE UPPER TROUGH HAS MOVED N OF THE DISCUSSION AREA. A BROAD UPPER RIDGE NOW DOMINATES THE W GULF ANCHORED INLAND OVER CENTRAL MEXICO. THE UPPER LOW ALONG THE E COAST OF FLORIDA EXTENDS AN UPPER TROUGH ACROSS FLORIDA NEAR TAMPA COVERING THE E GULF N OF 24N E OF 91W. THIS FLOW ALOFT IS NOW BEGINNING TO INDUCE UPPER LOW IN THE SW GULF NEAR 22N93W. A WEAK SURFACE TROUGH IS ALONG THE COAST OF MEXICO FROM TAMPICO TO VERACRUZ AT 11/0900 UTC. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ACROSS THE SW GULF S OF 25N W OF 91W. ISOLATED SHOWERS DOT THE REMAINDER OF THE S GULF S OF 26N. A SURFACE RIDGE EXTENDS FROM A 1023 MB HIGH OVER WESTERN NORTH CAROLINA TO OVER THE N GULF. SURFACE RIDGE WILL PERSIST THROUGH THU. THE SURFACE TROUGH IN THE SPECIAL FEATURES ABOVE IS EXPECTED TO MOVE SLOWLY W-NW ACROSS THE YUCATAN PENINSULA TODAY AND ENTER THE BAY OF CAMPECHE ON THU. A SURFACE LOW IS EXPECTED TO DEVELOP ALONG THE TROUGH OVER THE SW GULF LATER IN THE WEEK THEN INTENSIFY SLOWLY THROUGH SUN AS IT DRIFTS NW. THE LOW COULD POSSIBLY DEVELOP INTO A TROPICAL CYCLONE. CARIBBEAN SEA... AN UPPER RIDGE IS ANCHORED OVER THE NW CARIBBEAN COVERING THE AREA W OF 74W TO JUST ACROSS CUBA. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 11N-16N BETWEEN 73W-82W. THE REMAINDER OF ACTIVITY IN THE NW CARIBBEAN AND THE SURFACE TROUGH OVER THE YUCATAN ARE IN THE SPECIAL FEATURES ABOVE. THE MONSOON TROUGH EXTENDS FROM COLOMBIA NEAR 9N76W OVER COSTA RICA NEAR 9N81W THEN NW OVER NICARAGUA. ISOLATED SHOWERS/THUNDERSTORMS ARE S OF 11N BETWEEN COLOMBIA AND COSTA RICA. AN UPPER LOW IS IN THE E CARIBBEAN NEAR 15N69W WITH THE UPPER TROUGH COVERING THE REMAINDER OF THE CARIBBEAN. THE SURFACE TROUGH WILL MOVE INLAND OVER THE YUCATAN TODAY. OTHERWISE LITTLE CHANGE THROUGH THE END OF THE WEEK. HISPANIOLA... SKIES ARE CLEAR ACROSS THE ISLAND THIS MORNING. THE UPPER TROUGH CURRENTLY COVERING THE E CARIBBEAN WILL SHIFT W BY THU. CLOUDINESS WILL THEN GRADUALLY INCREASE WITH LOW LEVEL SHOWERS AND THE POTENTIAL ONCE AGAIN FOR AFTERNOON AND EVENING SHOWERS/THUNDERSTORMS WILL OCCUR. ATLANTIC OCEAN... THE PRIMARY CONCERNS FOR THE ATLC BASIN TONIGHT ARE TROPICAL STORM GABRIELLE IN THE W ATLC AND HURRICANE HUMBERTO IN THE E ATLC. SEE SPECIAL FEATURES ABOVE. AN UPPER LOW IS CENTERED OFF THE E COAST OF FLORIDA NEAR DAYTONA BEACH WITH AN UPPER TROUGH COVERING THE W ATLC N 24N W OF 70W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE OVER THE W ATLC FROM 21N-33N W OF 72W INCLUDING THE BAHAMA ISLANDS. AN UPPER LOW REMAINS IN THE E/CENTRAL ATLC NEAR 24N44W BUT IS NOT PRODUCING ANY SIGNIFICANT WEATHER. THE REMAINDER OF THE ATLC IS DOMINATED BY A WEAK SURFACE RIDGE ANCHORED BY A 1033 MB HIGH WELL N OF THE AZORES. A WEAK PRESSURE PATTERN WILL PREVAIL ACROSS THE MOST OF THE ATLC. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW/NR