000 AXNT20 KNHC 061129 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1000 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 32W S OF 23N MOVING W NEAR 10 KT. A 1012 MB LOW IS EMBEDDED ON THE WAVE AXIS NEAR 19N32W. 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 19N. THE WAVE ALSO COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/STRONG CONVECTION IS FROM 21N-23N BETWEEN 30W-32W. TROPICAL WAVE IS ALONG 44W S OF 20N MOVING W NEAR 12 KT. A 1012 MB LOW IS ALONG THE WAVE AXIS NEAR 15N44W. 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 15N. 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 NEAR THE WAVE AXIS. HOWEVER...SCATTERED SHOWERS ARE WITHIN 75 NM EITHER SIDE OF THE AXIS FROM 8N-12N AND FROM 16N-19N. TROPICAL WAVE IS ALONG 62W S OF 16N 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 14N15W 13N25W 17N29W 14N38W 10N46W 6N57W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 7N-15N BETWEEN 13W-19W. ISOLATED MODERATE CONVECTION IS FROM 9N-12N BETWEEN 37W-43W. ...DISCUSSION... GULF OF MEXICO... THE GULF REMAINS MOIST THIS MORNING WITH ISOLATED SHOWERS ACROSS MUCH OF THE BASIN. AS OF 0900 UTC...A SURFACE TROUGH IS IN THE NW GULF HUGGING THE COAST LINE EXTENDING ALONG 30N90W 29N94W 27N97W. ISOLATED SHOWERS/THUNDERSTORMS ARE WITHIN 300 SE OF THE TROUGH. THIS ACTIVITY IS ENHANCED BY UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER RIDGE DOMINATING THE MAJORITY OF THE GULF CENTERED OVER THE SRN BAY OF CAMPECHE NEAR 19N95W AND AN UPPER LEVEL TROUGH OVER THE CENTRAL UNITED STATES. A SECOND SURFACE TROUGH IS IN THE BAY OF CAMPECHE FROM 21N95W TO 16N95W. SURFACE CONVERGENCE NEAR THE TROUGH IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS S OF 22N BETWEEN 91W-97W. A SHORTWAVE UPPER LEVEL TROUGH IS OVER THE ERN GULF WITH AXIS ALONG 30N86W TO 23N81W. EXPECT SHOWERS/THUNDERSTORMS TO PERSIST FOR THE NEXT 24 HRS. CARIBBEAN SEA... AN UPPER LEVEL TROUGH OVER THE ERN GULF EXTENDS TO ERN CUBA NEAR 23N81W CONTINUING TO THE NW CARIBBEAN TO NEAR 17N86W. UPPER LEVEL DIFFLUENCE BETWEEN THIS UPPER TROUGH AND AN UPPER LEVEL RIDGE OVER THE CENTRAL CARIBBEAN CENTERED NEAR 13N75W IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS OFF THE COAST OF NICARAGUA AND COSTA RICA FROM 10N-15N BETWEEN 81W-85W. A SURFACE TROUGH EXTENDS ACROSS THE BAHAMAS AND ACROSS CENTRAL CUBA FROM 22N78W TO 20N79W. SHOWER ACTIVITY ASSOCIATED WITH THE TROUGH IS CONCENTRATED N OF THE BASIN OVER THE BAHAMAS. A FEW ISOLATED SHOWERS ARE OVER HISPANIOLA DUE TO SURFACE CONVERGENCE NEAR A SURFACE TROUGH TO THE N OF THE MONA PASSAGE. 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 62W TO CONTINUE WWD ACROSS THE ERN CARIBBEAN. ATLANTIC OCEAN... AS OF 0900 UTC...A SURFACE TROUGH LINES THE FLORIDA E COAST EXTENDING FROM 27N80W TO 31N79W. SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN 120 NM E OF THE TROUGH AXIS. THIS ACTIVITY IS ALSO 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 32N52W. AN UPPER LEVEL LOW CENTERED NEAR 29N67W INTRUDES INTO THE SW PORTION OF THE UPPER RIDGE. THIS UPPER LEVEL LOW SUPPORTS A SURFACE TROUGH EXTENDING FROM JUST N OF THE MONA PASSAGE NEAR 19N68W TO 29N63W. ISOLATED SHOWERS ARE WITHIN 300 NM E OF THE TROUGH AXIS. ANOTHER SURFACE TROUGH EXTENDS ACROSS ERN CUBA INTO THE ATLC FROM 22N78W TO NEAR 26N75W. SURFACE CONVERGENCE NEAR THE TROUGH IS SUPPORTING ISOLATED SHOWERS/THUNDERSTORMS ACROSS THE BAHAMAS FROM 21N-25N BETWEEN 74W-79W. ELSEWHERE ACROSS THE ATLC...A BROAD SURFACE RIDGE DOMINATES ANCHORED BY A 1022 MB HIGH NEAR 29N51W...AND A 1025 MB AZORES HIGH NEAR 37N21W. IN THE UPPER LEVELS...A NARROW UPPER LEVEL TROUGH IS E OF THE UPPER HIGH NEAR 33N55W. THE UPPER TROUGH HAS AXIS ALONG 36N25W TO 17N51W. TO THE E OF THE TROUGH ANOTHER UPPER LEVEL RIDGE IS CENTERED NEAR 20N24W. $$ WALTON