000 AXNT20 KNHC 101049 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT FRI JUL 10 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 EXTENDS FROM 19N27W TO 13N29W TO 5N30W MOVING W 15-20 KT. SATELLITE IMAGERY INDICATES THAT THIS WAVE COINCIDES WITHIN A BROAD AREA OF LOW/MID-LEVEL CYCLONIC TURNING. SATELLITE-DERIVED WINDS INDICATE CYCLONIC CURVATURE IN THE FLOW WITHIN THE 600-800 MB LAYER. DEEP CONVECTION NEAR THIS WAVE IS BEING SUPPRESSED BY THE PRESENCE OF LOW/MID-LEVEL DRY SAHARAN AIR...WITH DEEP CONVECTION MAINLY BEING DRIVEN BY LOW LEVEL CONVERGENCE ASSOCIATED WITH THE ITCZ. A TROPICAL WAVE IS APPROACHING THE LESSER ANTILLES AND EXTENDS FROM 19N58W TO 7N60W MOVING W 20-25 KT. THIS WAVE IS EMBEDDED WITHIN A BROAD INVERTED-V PATTERN IN THE COVERAGE OF LOW LEVEL CLOUDS...AS WELL AS A MAXIMUM IN DEEP LAYER MOISTURE BASED ON THE TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. SCATTERED MODERATE CONVECTION IS FROM 7N-12N BETWEEN 56W-62W...WHICH IS BEING ENHANCED BY UPPER LEVEL DIFFLUENCE. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 12N16W 10N27W 8N36W 6N46W 7N59W. SCATTERED MODERATE CONVECTION IS FROM 5N-8N E OF 18W. SCATTERED MODERATE CONVECTION IS ALSO FROM 5N-8N BETWEEN 18W-24W AND FROM 5N-7N BETWEEN 31W-39W. SIMILAR CONVECTION IS FROM 5N-9N BETWEEN 49W-55W. ...DISCUSSION... GULF OF MEXICO... AN UPPER HIGH OVER W TEXAS IS PROVIDING NLY FLOW AND ADVECTING DRY AIR OVER MUCH OF THE MIDDLE AND W GULF...HELPING TO SUSTAIN A SURFACE RIDGE ALONG 25N/26N. AN UPPER TROUGH ALONG THE E COAST OF THE U.S. EXTENDS INTO THE SE GULF WATERS. INSTABILITY ALONG THE TROUGH AXIS AND WITHIN THE DIFFLUENT ZONE IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS S OF 27N E OF 86W...AS REVEALED BY DOPPLER RADAR AND LIGHTNING DATA. SCATTERED SHOWERS AND TSTMS ARE ALSO OCCURRING OVER THE SW BAY OF CAMPECHE ASSOCIATED WITH THE INTERACTION OF A SFC TROUGH AND AN UPPER LOW. THIS ACTIVITY SHOULD DIMINISH BY TONIGHT AS BOTH FEATURES TRACK W. SFC RIDGING IS EXPECTED TO SHIFT NWD OVER THE WEEKEND CAUSING LIGHT AND VARIABLE FLOW OVER THE N WATERS AND MODERATE ELY WINDS OVER THE S WATERS. CARIBBEAN SEA... FRESH TO STRONG TRADE WINDS ARE OCCURRING BETWEEN THE SURFACE RIDGE OVER THE CENTRAL ATLC AND A BROAD TROUGH OVER NORTHERN SOUTH AMERICA...WITH THE STRONGEST FLOW NEAR THE COAST OF COLOMBIA. AN EARLIER QUIKSCAT PASS CONFIRMED THE STRONG WINDS NEAR THE COAST OF COLOMBIA AND ENHANCED FLOW IN THE WINDWARD PASSAGE. THESE WINDS WILL REMAIN STRONG OVER THE NEXT SEVERAL DAYS AS THE SUBTROPICAL RIDGE STRENGTHENS. ALOFT...AN UPPER LOW IS CENTERED NEAR JAMAICA. NLY FLOW W OF THE LOW IS PROMOTING FAIR WEATHER ACROSS THE NW CARIBBEAN. MOIST SLY FLOW E OF THE LOW AND A DIFFLUENT PATTERN OVER THE SW CARIBBEAN IS PRODUCING SOME UNSETTLED WEATHER. SCATTERED SHOWERS AND TSTMS ARE LIKELY S OF 13N W OF 80W AND OVER THE CENTRAL CARIBBEAN FROM 12N-17N BETWEEN 68W-74W. MORE SHOWERS AND TSTMS ARE OCCURRING OVER AND NEAR THE WINDWARD ISLANDS ASSOCIATED WITH THE TROPICAL WAVE AS DISCUSSED ABOVE. ATLANTIC OCEAN... MAIN AREA OF UNSETTLED WEATHER IS OVER THE WRN PORTION. SCATTERED SHOWERS AND TSTMS ARE OCCURRING N OF 28N W OF 70W ASSOCIATED WITH AN UPPER TROUGH OVER FLORIDA AND A FRONT EXTENDING FROM A LOW NEAR 33N71W TO N FLORIDA. AS THE UPPER TROUGH LIFTS N OF THE AREA DURING THE NEXT COUPLE DAYS...THE FRONT WILL LIKELY BECOME INCREASINGLY DIFFUSE WHILE DRIFTING SOUTHWARD INTO THE N WATERS. FARTHER E...AN UPPER LOW NEAR 22N62W AND A SFC TROUGH FROM 26N64W TO 20N68W IS PRODUCING SCATTERED SHOWERS AND TSTMS WITHIN 120 NM W OF THE SFC TROUGH AXIS CAPPED BY WIDESPREAD DRY AIR. THE REMAINDER OF THE BASIN IS RELATIVELY INACTIVE SUPPRESSED BY DEEP LAYER RIDGING AND ASSOCIATED STABLE AIR. THE SUBTROPICAL RIDGE IS EXPECTED TO STRENGTHEN SLIGHTLY OVER THE NEXT FEW DAYS INCREASING TRADES OVER THE TROPICS. $$ CANGIALOSI/COHEN