000 AXNT20 KNHC 071043 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT WED OCT 07 2009 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1000 UTC. ...SPECIAL FEATURE... TROPICAL STORM HENRI IS CENTERED NEAR 18.1N 56.1W AT 07/0900 UTC...OR ABOUT 400 NM E OF THE NRN LEEWARD ISLANDS. HENRI IS MOVING W NEAR 11 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM SUSTAINED WIND SPEEDS HAVE INCREASED TO 45 KT WITH GUSTS TO 55 KT. LITTLE CHANGE IN INTENSITY IS EXPECTED TODAY WITH WEAKENING FORECAST TO BEGIN TONIGHT. PLEASE READ THE NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/ WTNT25 KNHC AND THE PUBLIC ADVISORY UNDER MIATCPAT5/WTNT35 KNHC FOR MORE DETAILS. SWLY SHEAR IS KEEPING CONVECTION TO THE E OF THE CENTER. NUMEROUS STRONG CONVECTION IS FROM 17N-21N BETWEEN 52W-56W. SCATTERED MODERATE CONVECTION IS FROM 14N-17N BETWEEN 55W-57W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 45W S OF 10N MOVING W NEAR 15 KT. SATELLITE IMAGERY INDICATES LOW-LEVEL CYCLONIC FLOW AROUND THE WAVE AXIS. THE WAVE ALSO COINCIDES WITH A LOW AMPLITUDE DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED STRONG CONVECTION IS FROM 6N-12N BETWEEN 43W-48W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 6N-11N BETWEEN 48W-52W. TROPICAL WAVE IS ALONG 66W S OF 14N MOVING W NEAR 12 KT. THE WAVE LIES WITHIN A LOW-AMPLITUDE...BUT BROAD...DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED STRONG CONVECTION IS OVER VENEZUELA FROM 7N-8N BETWEEN 66W-70W. AN UPPER LEVEL TROUGH OVER THE ERN CARIBBEAN IS SHEARING A LINE OF SCATTERED MODERATE/STRONG CONVECTION NEAR THE WAVE AXIS FROM 13N70W TO 15N59W. THIS ACTIVITY IS MOST LIKELY ASSOCIATED MORE WITH THE UPPER TROUGH THAN THE WAVE. TROPICAL WAVE IS ALONG 95W S OF 18N MOVING W NEAR 15-20 KT. THE MAIN PORTION OF THE WAVE LIES IN THE E PACIFIC BASIN. HOWEVER...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS AFFECTING THE SW GULF OF MEXICO S OF 20N BETWEEN 94W-96W. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 10N15W 6N26W 7N24W 5N32W 8N42W 5N55W. SCATTERED MODERATE/STRONG CONVECTION IS OFF THE COAST OF AFRICA FROM 6N-11N BETWEEN 11W-17W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 100 NM N OF THE AXIS AND 150 NM S OF THE AXIS BETWEEN ALONG THE AXIS BETWEEN 20W-27W. ...DISCUSSION... THE GULF OF MEXICO... WEAK SURFACE RIDGE IS ACROSS THE BASIN WITH GENERALLY FAIR WEATHER THROUGHOUT. AN UPPER LEVEL RIDGE CENTERED OVER CENTRAL MEXICO NEAR 24N101W ALONG WITH DRY AIR AND SUBSIDENCE COVERS THE AREA SUPPORTING THE FAIR WEATHER. A FEW SHOWERS/THUNDERSTORMS ARE IN THE FAR SW GULF IN ASSOCIATION WITH A TROPICAL WAVE ALONG 95W. SEE ABOVE. ANTI-CYCLONIC FLOW IS AROUND THE SURFACE RIDGE WITH WINDS UP TO 20 KT IN THE WRN GULF. EXPECT THE RIDGE TO PERSIST FOR THE NEXT FEW DAYS. THE CARIBBEAN SEA... AN UPPER LEVEL LOW IS OVER THE WRN CARIBBEAN CENTERED OFF THE COAST OF NICARAGUA NEAR 15N83W. THE UPPER LOW IS SUPPORTING ISOLATED SHOWERS/THUNDERSTORMS ACROSS THE WRN BASIN S OF 19N BETWEEN 75W-84W. ANOTHER UPPER LEVEL TROUGH IS LOCATED OVER THE ERN BASIN WITH AXIS FROM 14N71W ACROSS THE WINDWARD ISLANDS INTO THE ATLC. MOIST SWLY AND DIFFLUENT FLOW AROUND THE UPPER TROUGH IS SUPPORTING A LINE OF SCATTERED SHOWERS/THUNDERSTORMS FROM 13N70W TO 15N59W. A TROPICAL WAVE ALONG 66W MAY ALSO BE ENHANCING SOME OF THIS SHOWER ACTIVITY. MODERATE TO FRESH TRADEWINDS ARE ACROSS MUCH OF THE BASIN WITH STRONGER WINDS IN THE SW AND ERN CARIBBEAN. EXPECT THE TROPICAL WAVE ALONG 66W TO CONTINUE TO MOVE WWD. THE ATLANTIC OCEAN... TROPICAL STORM HENRI REMAINS THE BIGGEST WEATHER MAKER OVER THE ATLC. SEE SPECIAL FEATURES ABOVE. A COLD FRONT CLIPS THE NW PORTION OF THE BASIN FROM 32N75W TO 31N79W CONTINUING AS A STATIONARY FRONT TO 32N85W. NO SHOWERS ARE CURRENTLY ASSOCIATED WITH THE FRONT. AN UPPER LEVEL RIDGE COVERS THE WRN ATLC W OF 70W EXTENDING FROM THE GULF OF MEXICO. AN UPPER LEVEL TROUGH IS TO THE E BETWEEN 45W-70W SUPPORTING A COLD FRONT EXTENDING THROUGH THE N CENTRAL ATLC AND BRUSHES THE AREA NEAR 31N54W. CLOUDINESS AND POSSIBLE ISOLATED SHOWERS ARE WITHIN 250 NM SE OF THE FRONT. THE REMAINDER OF THE ATLC IS DOMINATED BY A BROAD SURFACE RIDGE ANCHORED BY SEVERAL SURFACE HIGHS. A 1020 MB HIGH IS CENTERED NEAR 26N66W TO THE NW OF T.S. HENRI. A 1022 MB HIGH IS CENTERED NEAR 31N60W TO THE W OF THE COLD FRONT BRUSHING THE CENTRAL ATLC. A PAIR OF 1022 MB HIGHS ARE CENTERED NEAR 25N40W AND 31N37W TO THE NE OF HENRI...AND E OF THE COLD FRONT IN THE CENTRAL ATLC. A WEAK SURFACE TROUGH EXTENDS FROM ANOTHER COLD FRONT N OF THE DISCUSSION AREA FROM 31N17W TO 27N30W. NO SHOWERS ARE CURRENTLY ASSOCIATED WITH THE TROUGH. IN THE UPPER LEVELS...AN UPPER LEVEL TROUGH EXTENDS FROM 29N36W TO 44N13W SUPPORTING THE SURFACE TROUGH IN THE ERN BASIN. AN UPPER LEVEL RIDGE COVERS THE BASIN S OF 26N E OF THE LESSER ANTILLES CENTERED NEAR 13N33W. $$ WALTON