000 AXNT20 KNHC 101751 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...TROPICAL WAVES... A TROPICAL WAVE EXTENDS FROM 17N29W TO 5N31W MOVING W 15-20 KT. SATELLITE IMAGERY INDICATES THE WAVE COINCIDES WITH 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 THE WAVE IS BEING SUPPRESSED BY THE PRESENCE OF LOW TO MIDDLE LEVEL DRY SAHARAN AIR LAYER...WITH DEEP CONVECTION CONFINED MAINLY NEAR THE ITCZ AXIS FROM 5N-8N BETWEEN 30W-36W. A TROPICAL WAVE IS ACROSS THE LESSER ANTILLES AND EXTENDS FROM 22N60W TO 9N63W MOVING W 20-25 KT. THIS WAVE IS EMBEDDED WITHIN A BROAD HIGH AMPLITUDE INVERTED-V CLOUD SIGNATURE...AS WELL AS A MAXIMUM IN DEEP LAYER MOISTURE BASED ON THE TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. WHILE THIS WAVE CONTINUES TO INTERACT WITH THE SAHARAN AIR LAYER OVER THE ERN CARIBBEAN...CONVECTION IS CONFINED TO SCATTERED SHOWERS E OF 65W AND OVER THE LESSER ANTILLES. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 13N16W 10N28W 7N34W 6N47W 9N60W. SCATTERED MODERATE CONVECTION IS FROM 5N-8N BETWEEN 13W-36W. SIMILAR CONVECTION IS FROM 6N-11N BETWEEN 51W-61W. ...DISCUSSION... GULF OF MEXICO... AN UPPER HIGH OVER W TEXAS IS PROVIDING N-NE FLOW ALOFT AND ADVECTING DRY AIR OVER MUCH OF THE MIDDLE AND WRN GULF...HELPING TO SUSTAIN A SURFACE RIDGE ALONG 27N. AN UPPER TROUGH ALONG THE E COAST OF THE U.S. EXTENDS ACROSS THE FLORIDA PENINSULA AND INTO THE SE GULF WATERS. INSTABILITY ALONG THE TROUGH AXIS AND WITHIN THE DIFFLUENT ZONE IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS S OF 28N E OF 85W...FOCUSED ALONG A WEAK SURFACE TROUGH THAT EXTENDS FROM ST. AUGUSTINE FLORIDA INTO THE E/CENTRAL GULF NEAR 28N85W. SCATTERED SHOWERS AND TSTMS ARE ALSO OCCURRING S OF 25N W OF 93W OVER THE SW GULF ASSOCIATED WITH THE INTERACTION OF A SURFACE TROUGH ALONG 24N95W TO 18N96W AND AN INVERTED UPPER TROUGH MOVING ACROSS CENTRAL INTERIOR MEXICO. THE SURFACE RIDGING IS EXPECTED TO SHIFT NWD OVER THE WEEKEND CAUSING LIGHT AND VARIABLE FLOW OVER THE NRN WATERS AND MODERATE ELY WINDS OVER THE SRN WATERS. CARIBBEAN SEA... FRESH TO STRONG TRADE WINDS ARE OCCURRING BETWEEN THE SURFACE RIDGE OVER THE CENTRAL ATLC AND A BROAD TROUGH OVER NRN SOUTH AMERICA...WITH THE STRONGEST FLOW NEAR THE COAST OF COLOMBIA. AN EARLIER QUIKSCAT PASS AROUND 1100 UTC CONFIRMED THE STRONG WINDS NEAR THE COAST OF COLOMBIA UP TO 30 KT. THESE WINDS WILL REMAIN STRONG OVER THE NEXT SEVERAL DAYS AS THE SUBTROPICAL RIDGE STRENGTHENS. ALOFT...AN UPPER LOW IS CENTERED NE OF JAMAICA NEAR 18N76W. 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 OBSERVED S OF 13N W OF 79W TO OVER INTERIOR NICARAGUA AND HONDURAS AS WELL AS ISOLATED SHOWERS AND TSTMS OVER THE N/CENTRAL CARIBBEAN FROM 18N-21N BETWEEN 74W-78W. MORE SHOWERS AND TSTMS ARE OCCURRING ACROSS THE ERN CARIBBEAN AND LESSER ANTILLES E OF 65W IN ASSOCIATION WITH THE TROPICAL WAVE DISCUSSED ABOVE. ATLANTIC OCEAN... MAIN AREA OF UNSETTLED WEATHER IS OVER THE WRN PORTION OF THE BASIN WITH SCATTERED SHOWERS AND TSTMS OCCURRING W OF 74W ASSOCIATED WITH AN UPPER TROUGH OVER FLORIDA AND A FRONTAL BOUNDARY EXTENDING ALONG 32N72W TO NEAR ST. AUGUSTINE FLORIDA AND FOCUSED ON A 1017 MB SURFACE LOW CENTERED NEAR 31N80W. AS THE UPPER TROUGH LIFTS N OF THE AREA DURING THE NEXT COUPLE DAYS...THE FRONT IS EXPECTED TO BECOME DIFFUSE WHILE DRIFTING SOUTHWARD INTO THE N WATERS. FARTHER E...AN UPPER LOW NEAR 23N63W AND A SURFACE TROUGH FROM 26N59W TO 22N69W IS PRODUCING SCATTERED SHOWERS AND TSTMS WITHIN 120 NM W OF THE SURFACE TROUGH AXIS CAPPED BY WIDESPREAD DRY AIR. THE REMAINDER OF THE BASIN IS RELATIVELY INACTIVE SUPPRESSED BY DEEP LAYER RIDGING AND ASSOCIATED STABLE AIR ANCHORED ON A PAIR OF 1026 MB SURFACE HIGHS CENTERED NEAR 31N41W AND 30N49W. THIS SUBTROPICAL RIDGE IS FORECAST TO STRENGTHEN SLIGHTLY OVER THE NEXT FEW DAYS INCREASING TRADES OVER THE TROPICS. $$ HUFFMAN