000 AXNT20 KNHC 151043 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT WED JUL 15 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 1045 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 24W S OF 15N MOVING W NEAR 15 KT. RECENT VISIBLE SATELLITE IMAGERY DEPICTS MID-LEVEL CYCLONIC CIRCULATION NEAR THIS WAVE. SCATTERED MODERATE CONVECTION IS FROM 7N-12N BETWEEN 23W-28W. A TROPICAL WAVE IS ALONG 40W/41W S OF 16N MOVING W NEAR 15 KT. THIS WAVE COINCIDES WITH A LOW AMPLITUDE MAXIMUM IN DEEP LAYER MOISTURE BASED ON THE TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. SCATTERED MODERATE CONVECTION IS FROM 11N-14N BETWEEN 38W-40W. A HIGHLY-AMPLIFIED TROPICAL WAVE IS OVER THE SW NORTH ATLC AND E CARIBBEAN...AND EXTENDS FROM 24N66W TO 15N68W TO 6N68W MOVING W 20-25 KT. UPPER AIR DATA FROM BARBADOS AND GUADELOUPE AT 15/0000 UTC INDICATE THAT THE WAVE IS FOLLOWED BY A STRONG EASTERLY 700-650 MB JET...WITH CORE WINDS OF 45 KT. RECENT SATELLITE IMAGERY SHOW A WELL-DEFINED AND HIGHLY-AMPLIFIED INVERTED-V PATTERN EVIDENT IN THE COVERAGE OF LOW-LEVEL CLOUDS NEAR THE WAVE...COINCIDING WITH A MAXIMUM IN TOTAL PRECIPITABLE WATER. THE WAVE IS LEADING AN AREA OF ABUNDANT DRY LOW/MID-LEVEL SAHARAN AIR. THIS IS CONTRIBUTING TO SUFFICIENT LOW LEVEL ATMOSPHERIC LIFT TO SUPPORT SCATTERED SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WITHIN 180 NM E OF THE WAVE AXIS. THE DRY AIR...ALONG WITH STABLE ATMOSPHERIC CONDITIONS BENEATH AN UPPER LEVEL HIGH OVER THE E CARIBBEAN...ARE LIMITING THE AREAL COVERAGE OF DEEP CONVECTION NEAR THE WAVE. THE AFOREMENTIONED DRY AIR IS LIKELY CONTRIBUTING TO STRONG DOWNDRAFTS AND GUSTY OUTFLOW WINDS WITH THE SHOWER AND THUNDERSTORM ACTIVITY. THE STRONG EASTERLY JET FOLLOWING THE WAVE HAS PUSHED THE SOUTHERN PORTIONS OF THE WAVE SUFFICIENTLY FAR TO THE WEST TO HAVE FRACTURED THE WAVE ALONG 24N. N OF 24N...A SURFACE TROUGH IS ANALYZED FROM 30N62W TO 24N66W...WITH SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THE SURFACE TROUGH. THIS TROUGH WAS PREVIOUSLY A PART OF THE TROPICAL WAVE. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 11N15W 10N27W 10N37W 9N50W 9N61W. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS FROM 6N-14N E OF 22W. SCATTERED MODERATE CONVECTION IS FROM 10N-12N BETWEEN 42W-46W. SCATTERED MODERATE CONVECTION IS ALSO FROM 8N-10N BETWEEN 53W-56W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL HIGH IS OVER THE NW GULF OF MEXICO CENTERED NEAR 28N95W WITH A SURFACE RIDGE ACROSS THE N GULF AND A 1019 MB SURFACE HIGH OVER THE FLORIDA PENINSULA NEAR 29N82W. GENERALLY FAIR WEATHER IS PRESENT ACROSS THE GULF. WINDS ARE LIGHT AND VARIABLE IN THE VICINITY OF THE SURFACE RIDGE ACROSS THE N GULF...WITH ANTICYCLONIC FLOW AROUND THE RIDGE SUPPORTING A BROAD SWATH OF E WINDS OF 10-15 KT ACROSS THE S HALF OF THE GULF. THESE CONDITIONS ARE FORECAST TO CONTINUE DURING THE NEXT SEVERAL DAYS. HOWEVER...NE WINDS UP TO 20 KT ARE FORECAST TO OCCUR DURING THE LATE AFTERNOON AND EVENING HOURS DURING THE NEXT SEVERAL DAYS NEAR THE COAST OF THE YUCATAN PENINSULA. LITTLE CHANGE IS EXPECTED OVER THE NEXT DAY OR TWO AS BOTH THE UPPER AND SFC RIDGE REMAIN IN PLACE. CARIBBEAN SEA... FRESH TO STRONG TRADE WINDS ARE OCCURRING BETWEEN THE SUBTROPICAL RIDGE OVER THE CENTRAL ATLC AND A BROAD TROUGH OVER NORTHERN SOUTH AMERICA...WITH THE STRONGEST FLOW NEAR THE COAST OF COLOMBIA. THE QUIKSCAT PASS AROUND 14/2315 UTC INDICATED A LARGE AREA OF NE TO E WINDS OF 20 TO 30 KT ACROSS THE CENTRAL CARIBBEAN. THESE WINDS WILL REMAIN STRONG OVER THE NEXT SEVERAL DAYS AS THE SUBTROPICAL RIDGE REMAINS IN PLACE AND A TROPICAL WAVE MOVES ACROSS THE AREA. IN FACT...GALE CONDITIONS ARE FORECAST TO BEGIN LATER TODAY THROUGH THE END OF THE WEEK...AS THE LOW LEVEL FLOW STRENGTHENS ACROSS THE CARIBBEAN AND INTERACTS THE LOCAL TOPOGRAPHICAL VARIATIONS NEAR THE COAST OF COLOMBIA. INSTABILITY ASSOCIATED WITH AN UPPER LEVEL LOW OVER THE N CENTRAL CARIBBEAN CENTERED NEAR 18N82W AND AN UPPER LEVEL TROUGH OVER THE SW CARIBBEAN IS RESULTING IN SCATTERED SHOWERS AND THUNDERSTORMS WITHIN 120 NM OF THE COAST OF CENTRAL AMERICA S OF 16N. ALSO...THE TROPICAL WAVE MOVING ACROSS THE E CARIBBEAN IS ACCOMPANIED BY...AND FOLLOWED BY...STRONGER WINDS AND A STRONG SURGE OF SAHARAN AIR. ATLANTIC OCEAN... DEEP LAYER MOISTURE IS COMBINING WITH UPPER LEVEL DIFFLUENCE IN NORTHWESTERLY FLOW ALOFT TO RESULT IN SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ACROSS THE SW NORTH ATLC N OF 30N W OF 77W. ALSO...SCATTERED SHOWERS AND ISOLATED TSTMS ARE N OF 24N BETWEEN 66W-75W. THIS ACTIVITY IS BEING SUPPORTED BY LOW LEVEL CONVERGENCE NEAR A SURFACE TROUGH EXTENDING FROM 29N69W TO 25N74W. THIS ACTIVITY IS ALSO SUPPORTED BY ATMOSPHERIC INSTABILITY ASSOCIATED WITH AN UPPER TROUGH OVER THE SW NORTH ATLC. SUBSIDENCE AND GENERALLY FAIR WEATHER ARE PRESENT ACROSS MUCH OF THE CENTRAL AND E ATLC AROUND A BROAD SURFACE RIDGE WITH A 1029 MB HIGH NEAR 34N48W. ACROSS THE TROPICAL N ATLC... NORTHEASTERLY UPPER LEVEL FLOW IS IN PLACE...WITH STRONG UPPER LEVEL DIFFLUENCE SUPPORTING THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVE ALONG 40W/41W S OF 16N. $$ COHEN