000 AXNT20 KNHC 101047 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU SEP 10 2015 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 HENRI IS CENTERED NEAR 31.4N 61.0W AT 10/0900 UTC OR ABOUT 200 NM E-SE OF BERMUDA MOVING N AT 3 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. SCATTERED MODERATE CONVECTION IS FROM 30N-34N BETWEEN 55W-60W. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 10N32W TO 18N29W MOVING W AT 15 KT. THE WAVE COINCIDES WITH A RELATIVELY SHARP 700 MB TROUGH AND A MAXIMUM IN 850 MB RELATIVE VORTICITY STRETCHED WITHIN 120 NM EITHER SIDE OF THE WAVE AXIS. SCATTERED MODERATE CONVECTION IS FROM 12N-14N BETWEEN 29W-35W. SURFACE TROUGHING EXTENDS FROM 12N54W TO 19N53W MOVING W AT 15- 20 KT. THE TROUGH AND ASSOCIATED 1009 MB LOW ANALYZED ALONG THE TROUGH AXIS NEAR 15N54W...THE REMNANTS OF GRACE...REMAINS WEAK WITH A RECENT ASCAT PASS AROUND 10/0024 UTC INDICATING THE STRONGEST WINDS...RANGING FROM 20-25 KT...WITHIN 150 NM OF CENTER IN THE NE QUADRANT. SCATTERED MODERATE CONVECTION IS FROM 14N-16N BETWEEN 52W-56W. TROPICAL WAVE EXTENDS FROM 10N66W TO 17N64W MOVING W AT 20 KT. THE WAVE COINCIDES WITH RELATIVELY WEAK 700 MB TROUGHING BETWEEN 60W-66W WITH 850 MB RELATIVE VORTICITY MAXIMIZED FROM 10N-12N BETWEEN 63W-70W IN THE VICINITY OF THE SOUTHERN PORTION OF THE AXIS. WIDELY SCATTERED MODERATE CONVECTION IS FROM 12N-15N BETWEEN 59W-68W. TROPICAL WAVE EXTENDS FROM 10N81W TO 17N80W MOVING W AT 25 KT. THE WAVE COINCIDES WITH SUBTLE 700 MB TROUGHING STRETCHING FROM OVER JAMAICA ALONG THE WAVE AXIS TO OVER WESTERN PANAMA. NUMEROUS MODERATE AND SCATTERED STRONG CONVECTION IS FROM 08N- 13N BETWEEN 76W-88W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 09N13W TO 11N24W THEN RESUMES NEAR 15N24W TO 10N32W TO 10N38W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 10N38W TO 08N43W TO 12N53W. SCATTERED MODERATE CONVECTION IS FROM 05N-17N BETWEEN 10W-21W. THIS CONVECTION IS ASSOCIATED WITH THE NEXT TROPICAL WAVE TO EMERGE OFF THE WEST AFRICAN COAST LATER TODAY. ...DISCUSSION... GULF OF MEXICO... A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH CONTINUES TO MOVE OVER THE OHIO AND SOUTHERN MISSISSIPPI RIVER VALLEYS THIS MORNING DIPPING SOUTHWARD TO A BASE OVER THE NW AND NORTH-CENTRAL GULF WATERS. A NARROW SHEAR AXIS ALOFT EXTENDS SOUTH-SOUTHWESTWARD TO AN UPPER LEVEL LOW CENTERED NEAR 19N95W. THE UPPER LEVEL LOW REMAINS RELATIVELY WEAK AS TWO BROAD ANTICYCLONES INFLUENCE MUCH OF THE GULF...ONE CENTERED OVER THE FLORIDA STRAITS NEAR 24N81W AND THE OTHER CENTERED OVER THE SOUTHERN BAJA CALIFORNIA PENINSULA NEAR 24N109W. GENERALLY THE ANTICYCLONIC CIRCULATIONS ARE PROVIDING THE BASIN WITH MIDDLE TO UPPER LEVEL CLOUDINESS... AND POSSIBLE ISOLATED SHOWERS STRETCHING FROM THE EASTERN BAY OF CAMPECHE N-NE TO THE EASTERN GULF WATERS. OTHERWISE...SURFACE RIDGING INFLUENCES THE GULF WITH GENTLE TO MODERATE BREEZE CONDITIONS AROUND A 1016 MB HIGH CENTERED NEAR 26N87W. THE RIDGING IS FORECAST TO HOLD IN PLACE THROUGH LATE FRIDAY INTO SATURDAY WHEN THEREAFTER WEAK SURFACE TROUGHING IS EXPECTED TO EXTEND ALONG THE GULF COAST FROM THE FLORIDA BIG BEND TO NEAR GALVESTON BAY. CARIBBEAN SEA... A MIDDLE TO UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED NEAR 18N86W AND INFLUENCES MUCH OF THE WESTERN CARIBBEAN WITH RELATIVELY DRY NORTHERLY FLOW W OF 72W. MOST ACTIVE CONVECTION REMAINS ACROSS PORTIONS OF CENTRAL AMERICA THIS MORNING IN ASSOCIATION WITH TROPICAL WAVES...ONE ALONG 81W AND THE OTHER ALONG 93W. THE TROPICAL WAVE ALONG 81W AND THE CLOSE PROXIMITY OF THE MONSOON TROUGH AXIS IS GENERATING NUMEROUS SHOWERS AND SCATTERED TSTMS S OF 13N BETWEEN 75W-88W. OTHERWISE...FARTHER EAST...ANOTHER TROPICAL WAVE ALONG 65W IS PROVIDING INCREASED MOISTURE AND CLOUDINESS FOR THE SE CARIBBEAN WITH ISOLATED SHOWERS AND TSTMS S OF 15N E OF 68W...INCLUDING THE ABC ISLANDS...AND PORTIONS OF THE WINDWARD ISLANDS. OTHERWISE... MODERATE TO FRESH TRADE PREVAIL WITH SLIGHTLY STRONGER WINDS NOTED S OF 13N BETWEEN 72W-77W OFF THE COAST OF COLOMBIA. ...HISPANIOLA... CURRENTLY MOSTLY CLEAR SKIES PREVAIL WITH DRY NORTHERLY FLOW ALOFT PROVIDING OVERALL STABLE CONDITIONS THIS MORNING. ATLANTIC OCEAN... MOST OF THE SW NORTH ATLC IS UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE CENTERED NEAR 24N80W OVER THE FLORIDA STRAITS. THE RIDGING ALOFT SUPPORTS A 1016 MB HIGH CENTERED NEAR 28N74W PROVIDING MOSTLY FAIR CONDITIONS WITH ISOLATED SHOWERS OCCURRING WITHIN THE NW PERIPHERY FROM 30N-33N BETWEEN 76W-80W...AND FROM 26N-32N BETWEEN 66W-72W. THE LATTER IS LIKELY ASSOCIATED WITH A MID-LEVEL SHORTWAVE TROUGH NOTED ON WATER VAPOR IMAGERY NEAR 29N71W AND THE PARENT UPPER LEVEL LOW CENTERED NEAR 35N66W. FARTHER EAST...TROPICAL STORM HENRI IS TRACKING GENERALLY NORTHWARD ON THE EASTERN PERIPHERY OF THE UPPER LEVEL LOW AND WITHIN THE INFLUENCE OF AN UPPER LEVEL ANTICYCLONE CENTERED NEAR 28N55W. OTHERWISE...THE REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF SURFACE RIDGING ANCHORED BY A PAIR OF 1018 MB HIGHS CENTERED NEAR 30N24W AND 25N35W. ON THE NORTHERN PERIPHERY OF THIS RIDGING...WEAKENING FRONTAL BOUNDARY EXTENDS FROM 32N31W INTO A 1016 MB LOW NEAR 29N36W INTO ANOTHER 1016 MB LOW CENTERED NEAR 29N44W. ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THE BOUNDARY. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN