000 AXNT20 KNHC 081742 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT FRI JUN 08 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 TROPICAL WAVE IS IN THE E ATLC ALONG 32W S OF 11N MOVING W NEAR 15 KT. THIS WAVE HAS LOST A GREAT DEAL OF ITS STRUCTURE AND CONVECTION SINCE YESTERDAY. THE CURRENT PSN OF THE WAVE FOLLOWS CONTINUITY AND IS PLACED ON THE UPSHEAR SIDE OF ASSOCIATED SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 240 NM W OF THE AXIS. A TROPICAL WAVE IS ALONG 55W S OF 11N MOVING W NEAR 15 KT. WAVE PASSAGE WAS EVIDENT IN THE RAOBS AT CAYENNE FRENCH GUIANA BETWEEN 07/1100 UTC AND 07/2300 UTC. UNLIKE THE WAVE TO THE E...THIS ONE HAS BECOME MORE CONVECTIVELY ACTIVE THAN THE PAST COUPLE DAYS WITH SCATTERED MODERATE FROM 7N-10N BETWEEN 52W-56W. ONE POSSIBLE REASON FOR THE DEVELOPMENT OF CONVECTION IS THE UPPER ENVIRONMENT AS THE WAVE IS NOW LOCATED IN A DIFFLUENT ZONE TO THE E OF A SWLY JET BRANCH. A TROPICAL WAVE IS PUSHING ACROSS THE SRN CARIB ALONG 67W S OF 15N MOVING W NEAR 15 KT. THE UPPER AIR TIME SECTION FROM TRINIDAD SHOWED A CLEAR WAVE PASSAGE EARLY IN THE DAY YESTERDAY. THIS WAVE IS LESS IMPRESSIVE THAN IT WAS OVER THE PAST COUPLE OF DAYS WITH MOST OF ITS THICK CLOUDINESS AND SHOWER ACTIVITY DIMINISHED AS THE FEATURE NOW LIES IN A SUBSIDENT ENVIRONMENT. HOWEVER...24-H PRES TENDENCIES IN THE SE CARIB SHOW A RATHER PRONOUNCED 2-3 MB DROP SHOWING THE STRENGTH OF THIS FEATURE. BASED ON THOSE REPORTS THE WAVE AXIS MAY BE SHIFTED A LITTLE FURTHER W ON THE 18Z ANALYSIS...CLOSER TO 70W. A TROPICAL WAVE HAS BEEN ADJUSTED INTO THE EPAC ALONG 89W/90W S OF 13N MOVING W 10-15 KT. THIS WAVE WAS CHALLENGING TO TRACK OVER THE PAST FEW DAYS WITH LITTLE WAVE SIGNATURE NOTED IN SFC OBS OR SATELLITE IMAGES. HOWEVER...THIS MORNING'S VIS PICTURES SHOWS A FAIR AMOUNT OF LOW TO MID LEVEL CYCLONIC TURNING NEAR 10N90W...LEADING TO THE SHIFTED PSN. FOR MORE DETAILS REFER TO THE EAST PACIFIC TWD...MIATWDEP. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 5N9W 6N21W 5N30W 4N40W 6N53W. BESIDES FOR CONVECTION DISCUSSED ABOVE...CLUSTERS OF SCATTERED MODERATE IS WITHIN 240 NM N AND 180 NM S OF THE AXIS E OF 22W. THIS ACTIVITY IS BEING ENHANCED BY A POSSIBLE LOW AMPLITUDE TROPICAL WAVE NEAR 20W AND A LARGE WAVE THAT IS STILL INLAND OVER AFRICA. THESE SYSTEMS WILL BE FURTHER ASSESSED AND POSSIBLY ADDED TO THE MAP WITHIN THE NEXT DAY OR TWO AS THEY PUSH OFF OR FURTHER FROM THE COAST. ...DISCUSSION... THE GULF OF MEXICO... THE WRN PERIPHERY OF A W ATLC SFC RIDGE STRETCHES ACROSS THE GULF. THIS RIDGE IS PRODUCING MODERATE TO FRESH SELY RETURN FLOW IN THE MID AND W GULF...WITH LIGHTER WINDS IN THE E GULF CLOSER TO THE HIGH PRES CENTER. ALOFT...THE PATTERN IS CONFLUENT BETWEEN AN UPPER HIGH CENTERED OVER S MEXICO AND AN UPPER LOW OVER FLORIDA. THIS PATTERN IS LEADING TO A DRY STABLE AIRMASS ACROSS THE MAJORITY OF THE REGION AIDING IN THE WIDESPREAD FAIR WEATHER. HOWEVER...INSTABILITY NEAR THE UPPER LOW IS FUELING SCATTERED SHOWERS AND TSTMS ACROSS THE ERN HALF OF CENTRAL FLORIDA...SOME OF THESE MAY ROTATE INTO THE EXTREME ERN GULF WATERS LATER TODAY. LOOKING FURTHER AHEAD...SFC WINDS ARE ANTICIPATED TO RELAX THIS WEEKEND AS WEAK HIGH PRES DEVELOPS IN THE N CENTRAL GULF. THE CARIBBEAN SEA... THE MOST ACTIVE WEATHER IN THE REGION IS OVER PANAMA...COSTA RICA AND THE EXTREME SW CARIB WHERE IR IMAGERY AND LIGHTNING DATA DEPICT NUMEROUS MODERATE/SCATTERED STRONG CONVECTION S OF 11N W OF 77W. THIS ACTIVITY APPEARS MOSTLY TIED TO THE ITCZ WITH SOME ENHANCEMENT FROM WEAK DIFFLUENCE ALOFT. BESIDES FOR THIS AREA OF CONVECTION...TROPICAL WAVES ARE THE MAIN STORY WITH ONE IN THE SE CARIB AND THE OTHER ON THE APPROACH TOWARD THE WINDWARD ISLANDS. THE LATTER IS AIDING IN SCATTERED SHOWERS AND ISOLATED TSTMS ACROSS THE LESSER ANTILLES. FOR MORE DETAILS REFER TO THE TROPICAL WAVES SECTION ABOVE. OTHERWISE...MODERATE TO FRESH TRADES AND FAIR WEATHER DOMINATE AS A LARGE AREA OF DRY SINKING AIR LIES ALOFT ASSOCIATED WITH WEAK UPPER RIDGING. LOOKING AHEAD...A FEW COMPUTER MODELS SHOW MOISTURE INCREASING AND SPREADING W ACROSS THE SRN CARIB THIS WEEKEND. ATLANTIC OCEAN... INSTABILITY ASSOCIATED WITH A WELL DEFINED UPPER LOW SPINNING NEAR S FLA IS FUELING SCATTERED SHOWERS AND TSTMS W OF 74W S OF 29N...WHICH INCLUDES CUBA...THE BAHAMAS AND A PORTION OF FLORIDA. THE STRONGEST ACTIVITY...SOME POSSIBLY SEVERE...IS OVER LAND WHERE THERE IS ENHANCEMENT FROM HEATING AND SEABREEZES. THIS MORNING'S QSCAT PASS INDICATED THAT THERE WAS NOT A SFC FEATURE TIED TO THIS UPPER SYSTEM. IN FACT...SFC HIGH PRES RIDGING IS THE RULE IN THIS REGION WITH A 1022 MB CENTERED NEAR 33N70W. FARTHER NE...A LARGE VERTICALLY STACKED LOW PRES AREA IS LOCATED NEAR 40N57W. THIS SYSTEM IS SUPPORTING A WEAKENING COLD FRONT WHICH EXTENDS FROM 32N56W 28N62W. SCATTERED SHOWERS ARE WITHIN 180 NM E OF THE FRONT AND N OF 24N BETWEEN 49W-52W IN AN ASSOCIATED UPPER DIFFLUENT ZONE. MUCH OF THE CENTRAL AND EASTERN ATLC DISCUSSION AREA IS UNDER THE INFLUENCE OF WEAK SFC HIGH PRES RIDGING RESULTING IN LIGHT WINDS. AN UPPER LOW CONTINUES TO SPIN OVER THE CENTRAL ATLC NEAR 26N45W. THIS FEATURE IS ONLY GENERATING PATCHES OF CIRRUS. A S-SWLY JET ORIGINATES NEAR THE BASE OF THE ASSOCIATED TROUGHING AND RACES NE ALONG 14N50W 24N41W 30N39W THEN EWD TO THE S OF A LARGE OCCLUDED LOW PRES SYSTEM E OF THE AZORES. SCATTERED SHOWERS ARE POSSIBLE WITHIN 90 NM E OF THE LISTED JET AXIS. A DISSIPATING COLD FRONT IS OVER THE FAR NE PORTION OF THE AREA ALONG 32N12W 28N18W...PRODUCING VERY LITTLE WEATHER. $$ CANGIALOSI