000 AXNT20 KNHC 060513 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SUN SEP 06 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0430 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 31W/32W S OF 23N MOVING W NEAR 10 KT. A 1012 MB LOW IS EMBEDDED ON THE WAVE AXIS NEAR 18N31W. SATELLITE IMAGERY AND SATELLITE DERIVED WINDS INDICATE LOW-LEVEL CYCLONIC FLOW IN THE VICINITY OF THE WAVE AXIS CONCENTRATED AROUND THE LOW PRESSURE CENTER NEAR 18N. A 2344 UTC ASCAT SCATTEROMETER PASS CONFIRMS THE LOW-LEVEL CYCLONIC WINDS AROUND THE LOW CENTER. THE WAVE ALSO COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/STRONG CONVECTION IS FROM 20N-23N BETWEEN 29W-32W. TROPICAL WAVE IS ALONG 43W S OF 21N MOVING W NEAR 12 KT. A 1012 MB LOW IS ALONG THE WAVE AXIS NEAR 14N43W. SATELLITE IMAGERY AND SATELLITE DERIVED WINDS INDICATE LOW-LEVEL CYCLONIC FLOW IN THE VICINITY OF THE WAVE AXIS CONCENTRATED AROUND THE LOW PRESSURE CENTER NEAR 14N. A 2344 UTC ASCAT SCATTEROMETER PASS CONFIRMS THE LOW-LEVEL CYCLONIC WINDS AROUND THE WAVE AXIS. THE WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED TOTAL PRECIPITABLE WATER IMAGERY. A DRY SAHARAN AIR LAYER IS TO THE W OF THE WAVE AXIS WHICH IS LIMITING DEEP CONVECTION TO THE ITCZ AND A SMALL CLUSTER NEAR THE LOW CENTER. ISOLATED MODERATE CONVECTION IS FROM 8N-10N BETWEEN 41W-45W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 15N-17N BETWEEN 43W-44W. TROPICAL WAVE IS ALONG 61W S OF 17N MOVING W NEAR 12 KT. THE WAVE REMAINS RELATIVELY LOW-AMPLITUDE WITH NO ASSOCIATED DEEP CONVECTION DUE TO DRY SAHARAN DUST TO THE E OF THE WAVE AXIS. THE WAVE COINCIDES WITH A NARROW DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 12N16W 16N24W 18N30W 15N38W 10N46W 6N54W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 10N-17N BETWEEN 14W-19W. ISOLATED MODERATE CONVECTION IS FROM 9N-11N BETWEEN 35W-40W. ...DISCUSSION... GULF OF MEXICO... THE GULF REMAINS MOIST TONIGHT WITH ISOLATED SHOWERS ACROSS MUCH OF THE BASIN. A SURFACE TROUGH IS IN THE NW GULF EXTENDING ACROSS LOUISIANA FROM 31N90W TO 27N94W. SURFACE CONVERGENCE NEAR THE TROUGH ALONG WITH UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER RIDGE DOMINATING THE MAJORITY OF THE GULF CENTERED OVER MEXICO NEAR 18N99W AND AN UPPER LEVEL TROUGH OVER THE CENTRAL UNITED STATES ARE SUPPORTING ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS NW OF A LINE FROM 30N85W TO 19N92W INCLUDING THE BAY OF CAMPECHE. A SHORTWAVE UPPER LEVEL TROUGH IS OVER THE ERN GULF WITH AXIS ALONG 30N86W TO 22N81W. UPPER LEVEL DIFFLUENCE BETWEEN THIS UPPER TROUGH AND THE UPPER RIDGE IS ALSO SUPPORTING THE AFOREMENTIONED SHOWER ACTIVITY. EXPECT SHOWERS/THUNDERSTORMS TO PERSIST FOR THE NEXT 24 HRS. CARIBBEAN SEA... ISOLATED SHOWERS/THUNDERSTORMS ARE ACROSS THE FAR NW CARIBBEAN N OF 21N BETWEEN 78W-85W IN ASSOCIATION WITH UPPER LEVEL DIFFLUENT FLOW BETWEEN AN UPPER LEVEL TROUGH OVER THE ERN GULF EXTENDING TO THE NW CARIBBEAN TO NEAR 18N86W AND AN UPPER LEVEL RIDGE OVER THE CENTRAL CARIBBEAN CENTERED NEAR 13N75W. THIS UPPER DIFFLUENT FLOW IS ALSO ENHANCING SCATTERED SHOWERS/THUNDERSTORMS OFF THE COAST OF NICARAGUA AND HONDURAS FROM 11N-16N BETWEEN 82W-84W. A SURFACE TROUGH EXTENDS ACROSS ERN CUBA INTO THE CENTRAL CARIBBEAN FROM 22N75W TO 3N75W. SURFACE CONVERGENCE NEAR THE TROUGH IS SUPPORTING A FEW ISOLATED SHOWERS ACROSS CUBA AND HISPANIOLA. MODERATE TO FRESH TRADE WINDS ARE ACROSS MUCH OF THE BASIN BECOMING STRONG IN THE E CARIBBEAN. OVER THE NEXT 24 HR...EXPECT THE TROPICAL WAVE ALONG 61W TO MOVE INTO THE ERN CARIBBEAN. ATLANTIC OCEAN... ISOLATED SHOWERS/THUNDERSTORMS ARE ACROSS THE W ATLC N OF 28N W OF 76W. THIS ACTIVITY IS ENHANCED BY UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL TROUGH OVER THE ERN GULF AND AN UPPER LEVEL RIDGE OVER THE CENTRAL ATLC CENTERED NEAR 33N55W. AN UPPER LEVEL LOW CENTERED NEAR 28N67W INTRUDES INTO THE SW PORTION OF THE UPPER RIDGE. THIS UPPER LEVEL LOW SUPPORTS A SURFACE TROUGH EXTENDING FROM 25N66W TO 29N65W. ISOLATED SHOWERS ARE WITHIN 200 NM EITHER SIDE OF THE TROUGH AXIS. ANOTHER SURFACE TROUGH EXTENDS FROM THE CARIBBEAN ACROSS ERN CUBA TO NEAR 22N75W. SURFACE CONVERGENCE NEAR THE TROUGH IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS ACROSS THE BAHAMAS FROM 21N-25N BETWEEN 72W-78W. ISOLATED SHOWERS ARE N OF PUERTO RICO AND THE LEEWARD ISLANDS FROM 18N-24N BETWEEN 61W-66W. THIS ACTIVITY IS ENHANCED BY UPPER LEVEL DIFFLUENCE BETWEEN THE AFOREMENTIONED UPPER LEVEL LOW NEAR 28N67W AND AN UPPER LEVEL RIDGE OVER THE TROPICAL ATLC. ELSEWHERE ACROSS THE ATLC...A BROAD SURFACE RIDGE DOMINATES ANCHORED BY A 1024 MB HIGH NEAR 30N53W. IN THE UPPER LEVELS...A NARROW UPPER LEVEL TROUGH IS E OF THE UPPER HIGH NEAR 33N55W. THE UPPER TROUGH HAS AXIS ALONG 35N28W TO 20N48W. TO THE E OF THE TROUGH ANOTHER UPPER LEVEL RIDGE IS CENTERED NEAR 17N25W. $$ WALTON