000 AXNT20 KNHC 061741 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT FRI JUL 06 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND THE 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 VERY BROAD TROPICAL WAVE IS TITLED ALONG 5N30W 17N26W MOVING W 10-15 KT. THIS WAVE HAS A LARGE ENVELOPE OF LOW-LEVEL TURNING AND IS CAUSING QUITE A PERTURBATION IN THE ITCZ. DESPITE ITS SIZE...LITTLE SIGNIFICANT SHOWER ACTIVITY HAS BEEN ASSOCIATED WITH THIS FEATURE SINCE YESTERDAY. A TROPICAL WAVE IS ALONG 54W MOVING W NEAR 15 KT. A 1014 MB LOW IS ANALYZED ALONG THE AXIS NEAR 11N. WHILE CONVECTION HAS BEEN MINIMAL NEAR THIS LOW OVER THE PAST FEW DAYS...THE OVERALL CIRCULATION HAS REMAINED DISTINCT. HOWEVER...BASED ON THE LATEST VISIBLE IMAGES...THE CIRCULATION APPEARS TO HAVE OPENED AND THE LOW WILL LIKELY BE DROPPED AT 18Z. ONLY SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN 150 NM EITHER SIDE OF THE AXIS S OF 14N...AS THE WAVE REMAINS EMBEDDED IN A VERY STABLE ENVIRONMENT. A TROPICAL WAVE HAS BEEN ADJUSTED AHEAD SLIGHTLY ALONG 68W/69W MOVING W NEAR 15 KT. THIS ADJUSTMENT IS BASED MAINLY ON THE WWD SURGE OF MOISTURE NEAR THE BASE OF THE WAVE INLAND OVER VENEZUELA. REGARDLESS OF THE EXACT PSN...THIS FEATURE IS WEAK ONLY ENHANCING ISOLATED TO SCATTERED SHOWERS ACROSS PUERTO RICO AND HISPANIOLA. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 9N13W 11N27W 7N37W 4N46W 7N52W. CLUSTER OF SCATTERED MODERATE CONVECTION IS FROM 5N-7N BETWEEN 12W-14W. ELSEWHERE...NO SIGNIFICANT CONVECTION AT THE MOMENT. ...DISCUSSION... GULF OF MEXICO... WEAK SFC TROUGH REMAINS OVER CENTRAL FLORIDA AND THE E GULF EXTENDING FROM A 1016 MB LOW OFF THE NE FLORIDA COAST. DOPPLER RADAR IS NOT DETECTING MUCH TSTM ACTIVITY YET OVER THE PENINSULA...BUT IT'S LIKELY TO INCREASE AS THE AFTERNOON PROGRESSES. NUMEROUS SHOWERS AND TSTMS DO EXIST OVER EXTREME E TEXAS...LOUISIANA AND THEIR COASTAL WATERS SUPPORTED BY UPPER DIFFLUENCE BETWEEN AN UPPER HIGH IN THE MID GULF NEAR 27N89W AND AN UPPER TROUGH OVER THE SRN PLAINS. FURTHER S...AN UPPER LOW CONTINUES ITS WWD DRIFT CENTERED OVER THE GULF OF TEHAUNTEPEC. OVERALL...THIS UPPER PATTERN IS PRODUCING PATCHY HIGH LEVEL CLOUDS AND ISOLATED SHOWERS ACROSS THE GULF WATERS...WITH THE SHOWERS MOST CONCENTRATED S OF 28N E OF 87W IN THE VICINITY OF THE LOW-LEVEL BOUNDARY. THE SFC FLOW IS MAINLY GOVERNED BY A 1019 MB HIGH CENTERED NEAR 27N89W. THE STRONGEST WINDS...NEAR 15 KT...ARE IN THE SW AND THE EXTREME NW CORNERS OF THE GULF. WEAK RIDGING IS EXPECTED TO REMAIN IN CONTROL THIS WEEKEND...SO LITTLE SIGNIFICANT CHANGE IS ANTICIPATED. CARIBBEAN SEA... THE SURGE OF DRY AIR ALOFT CONTINUES TO PROPAGATE W ACROSS THE CARIB WITH THE LEADING EDGE SPREADING TO CENTRAL AMERICA. ANOTHER SURGE...OR ENHANCEMENT...OF STABLE AIR IS BEING ADVECTED W FROM THE TROPICAL ATLC TO 66W. THIS STABLE AIRMASS IS PROVIDING FAIR WEATHER ACROSS MUCH OF THIS REGION...WITH ONLY A COUPLE MINOR EXCEPTIONS. MID-HIGH LEVEL CLOUDS AND POSSIBLE ISOLATED SHOWERS LIE OVER MUCH OF CENTRAL AMERICA AND THE SW CARIB GENERATED BY AN UPPER LOW OVER THE GULF OF TEHUANTEPEC. DEEP MOISTURE IS JUST ABOUT NON-EXISTENT THOUGH WITH THE CONVECTIVE FOCUS NEAR THE ITCZ AXIS OVER THE EPAC WATERS. SCATTERED SHOWERS AND ISOLATED TSTMS ARE AFFECTING PARTS OF PUERTO RICO AND HISPANIOLA. WHILE THIS ACTIVITY IS TYPICAL ACROSS THE CARIB...IT APPEARS SLIGHTLY MORE ENHANCED THAN OTHER AREAS. THE TRADES REMAIN STRONG WITH QSCAT SHOWING A LARGE AREA OF 20-30 KT ELYS FROM 10N-18N...STRONGEST NEAR THE COAST OF COLOMBIA. ATLANTIC OCEAN... A 1016 MB SFC LOW IS CENTERED ABOUT 60 NM OFF THE JACKSONVILLE FLORIDA COASTLINE NEAR 30.5N80W. VISIBLE IMAGERY SHOWS A WEAK LOW-LEVEL SWIRL IN THIS VICINITY WITH ALL OF THE DEEP CLOUDINESS/CONVECTION LOCATED WELL TO THE E OF THE LOW-LEVEL CENTER FROM 27N-31N BETWEEN 75W-79W. SFC OBS SUGGEST THAT A WEAK TROUGH HANGS SW FROM THE LOW ACROSS CENTRAL FLORIDA WHICH COULD SET UP A FOCUS FOR TSTM ACTIVITY LATER TODAY. ELSEWHERE ...WIDESPREAD ABUNDANT DRY AIR IN THE MID AND UPPER LEVELS IS CAPPING THE TYPICAL PATCHY LOW-LEVEL STRATOCUMULUS DECK. WHILE UPPER RIDGING IS THE MAIN THEME...THERE IS SOME TROUGHING IN THE CENTRAL/E ATLC...BUT OVERALL THESE UPPER FEATURES ARE NOT PRODUCING MUCH WEATHER. AT THE SFC...SLIGHTLY WEAKENED 1028 MB AZORES HIGH PROVIDES LIGHT TO MODERATE TRADES ACROSS THE BULK OF THE ATLC. MODERATE TO STRONG NLY WINDS ARE NEAR THE AFRICAN COAST DUE TO THE TIGHTENING PRES GRADIENT BETWEEN THE HIGH AND INVERTED TROUGHING OVER THE CONTINENT. $$ CANGIALOSI