000 AXNT20 KNHC 041752 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED JUL 04 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. ...SPECIAL FEATURE... A 1013 MB LOW PRES SYSTEM IS CENTERED NEAR 11N44W OR ABOUT 1000 NM E OF THE LESSER ANTILLES. THE CIRCULATION IS WELL-DEFINED WITH THE LOW-LEVEL CENTER CLEARLY SEEN ON SATELLITE IMAGES AS IT IS EXPOSED TO THE N OF A WEAKENING BAND OF CONVECTION WITHIN 120 NM SSW OF THE CENTER. HOWEVER...THERE IS STILL POTENTIAL FOR DEVELOPMENT OVER THE NEXT DAY OR SO BEFORE CONDITIONS BECOME LESS FAVORABLE. ...TROPICAL WAVES... A TROPICAL WAVE IS TITLED ALONG 56W/57W MOVING W NEAR 15 KT. SHOWER ACTIVITY IS MINIMAL LIKELY CAPPED BY THE STRONGLY SUBSIDENT ENVIRONMENT THAT IT IS ENTRENCHED IN. DESPITE THE LACK OF DEEP MOISTURE...SATELLITE IMAGERY AND BUOY DATA SHOW ITS PRESENCE WITH A SURGE-LIKE STRUCTURE...TURNING IN THE SFC WINDS AND SLIGHTLY LOWER PRES NEAR THE AXIS. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 9N14W 6N22W 5N30W 9N39W 10N50W 11N59W. SCATTERED SHOWERS AND TSTMS ARE WITHIN 90 NM EITHER SIDE OF THE AXIS E OF 29W AND BETWEEN 55W-59W. ...DISCUSSION... GULF OF MEXICO... ACTIVE WEATHER CONTINUES ACROSS THE NW GULF...SE TEXAS AND WRN LOUISIANA...ROUGHLY N OF 28N W OF 91W. THESE NUMEROUS SHOWERS AND TSTMS ARE BEING PRODUCED BY UPPER DIFFLUENCE AND A WEAK SFC TROUGH OF LOW PRES OVER S TEXAS. IN THE E GULF...A 1015 MB LOW IS CENTERED BETWEEN FT MYERS AND TAMPA FLORIDA WITH A DISSIPATING FRONT EXTENDING NW TO LOUISIANA. THIS BOUNDARY IN COMBINATION WITH DIFFLUENCE ALOFT...BETWEEN A LARGE ELONGATED TROUGH NE OF THE REGION AND UPPER RIDGING OVER THE NW GULF...IS FIRING SCATTERED SHOWERS AND TSTMS WITHIN 60 NM EITHER SIDE OF THE FRONT. WEAK 1017 MB SFC HIGH PRES CENTER IS LOCATED IN THE SE GULF. TIGHTENED GRADIENT BETWEEN THIS HIGH AND LOW PRES OVER TEX/MEX IS PRODUCING MODERATE SELY WINDS ACROSS THE W GULF. THE UPPER FLOW IS MOSTLY N-NELY CAUGHT BETWEEN AN UPPER RIDGE OVER THE EPAC AND AN UPPER LOW OVER THE NW CARIB. THIS FLOW IS ADVECTING BROKEN HIGH LEVEL CLOUDINESS ACROSS THE BULK OF THE AREA. CARIBBEAN SEA... A SURGE OF DRY AIR ALOFT CONTINUES TO PROPAGATE W ACROSS THE CARIB ADVECTED TO ABOUT 76W FROM THE TROPICAL ATLC. THIS STABLE AIRMASS IS PROVIDING FAIR WEATHER ACROSS THIS AREA. THERE IS SLIGHTLY MORE MOISTURE FURTHER W SUPPORTED BY AN UPPER LOW SPINNING ABOVE THE NW CARIB NEAR 18N86W. BUT EVEN HERE...DEEP MOISTURE IS CONFINED TO THE SW CARIB AND OVER PANAMA/COSTA RICA...TIED TO THE ITCZ. A SMALLER LESS DEFINED UPPER LOW IS LOCATED IN THE WINDWARD PASSAGE GENERATING A FEW SHOWERS AND TSTMS. AT THE SFC...A 1124 Z QSCAT PASS SHOWED A LARGE AREA OF 20-30 KT ELY TRADES ACROSS MUCH OF THE CENTRAL AND W PORTIONS. THESE STRONG WINDS ARE CARRYING TYPICAL LOW CLOUD STREAMERS WITH EMBEDDED ISOLATED SHOWERS ACROSS THE REGION. LITTLE CHANGE IS EXPECTED TOMORROW. ATLANTIC OCEAN... A STATIONARY FRONTAL SYSTEM ENTERS THE AREA NEAR 32N56W AND EXTENDS WSW TO 27N72W THEN LIFTS NWD AS A WARM FRONT ALONG 29N79W TO A 1015 MB LOW OVER W CENTRAL FLORIDA. AN ILL-DEFINED PREFRONTAL TROUGH LIES S OF THE FRONT ALONG 25N/26N BETWEEN 70W-77W. LOW-LEVEL CONVERGENCE NEAR THESE LOW-LEVEL BOUNDARIES COMBINED WITH MOIST UPPER SWLY FLOW AND DIFFLUENCE...BETWEEN A LARGE ELONGATED TROUGH N OF THE REGION AND UPPER RIDGING IN THE GULF AND CENTRAL ATLC...IS PRODUCING SCATTERED SHOWERS AND TSTMS WITHIN 90 NM EITHER SIDE OF THE FRONTS. FARTHER E...RIDGING DOMINATES BOTH AT THE SFC AND ALOFT. THE SFC AZORES HIGH IS ANALYZED 1032 MB NEAR 36N27W. THIS HIGH IS PRODUCING A LARGE AREA OF MODERATE TRADES ACROSS THE ATLC. STRONG NLY WINDS ARE NEAR THE AFRICAN COAST DUE TO THE TIGHTENING PRES GRADIENT BETWEEN THE HIGH AND INVERTED TROUGHING OVER THE CONTINENT. THREE UPPER HIGHS ARE PROVIDING A VERY STABLE AIRMASS ACROSS THE CENTRAL AND E ATLC WITH ONLY LOW-LEVEL STABLE STRATOCUMULUS CLOUDS SEEN ACROSS MUCH OF THE BASIN. $$ CANGIALOSI