000 AXNT20 KNHC 041739 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SAT AUG 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. ...TROPICAL WAVES... HIGH AMPLITUDE TROPICAL WAVE EXTENDS ACROSS THE CAPE VERDE ISLANDS ALONG 24W S OF 22N MOVING W NEAR 15 KT. THIS WAVE CONTINUES TO EXHIBIT A LARGE WELL DEFINED AREA OF CYCLONIC TURNING IN THE LOW AND MID LEVEL CLOUDS WITH THE GREATEST ROTATION CURRENTLY ACROSS THE ISLANDS. DEEP CONVECTION REMAINS MINIMAL NEAR THIS ROTATION THOUGH. THE MORE PERSISTENT SCATTERED SHOWER/TSTM ACTIVITY HAS BEEN ACROSS THE SRN PORTION OF THE WAVE AND THE INTERSECTION OF THE ITCZ FROM 7N-14N BETWEEN 22W-29W. TROPICAL WAVE IS ALONG 40W/41W S OF 18N MOVING W NEAR 15 KT. THIS WEAK WAVE REMAINS DIFFICULT TO LOCATE AS IT IS EMBEDDED IN THE FLOW OF THE LARGER WAVES TO IT'S E AND W. STABLE SAHARAN DUST SURROUNDS THIS FEATURE...JUDGING BY THE CIMSS SAL PRODUCT AND THE HAZY LOOK ON VISIBLE IMAGES. ISOLATED SHOWERS AND TSTMS NEAR THE AXIS ARE MORE LIKELY ASSOCIATED WITH THE ITCZ. HIGH AMPLITUDE TROPICAL WAVE IS ALONG 56W/57W MOVING W 15-20 KT. THIS LARGE-SCALE WAVE REMAINS EASILY SEEN WITH A PRONOUNCED INVERTED-V SHAPE NOTED IN THE LOW AND MID LEVEL CLOUD FIELD. IN ADDITION...THREE BUOYS IN THE VICINITY OF 15N56W HELP DEPICT THE AXIS WELL SHOWING THE CLASSIC WIND SHIFT AND RELATIVE LOW PRESSURE AS COMPARED TO THE ENVIRONMENT. THIS WAVE HAS GAINED SOME DEEP MOISTURE TODAY BUT THIS IS LIKELY CONTRIBUTED TO THE INTERACTION WITH AN UPPER LOW NEAR 22N59W. SCATTERED SHOWERS AND TSTMS ARE WITHIN 150 NM EITHER SIDE OF THE AXIS. STRONG TROPICAL WAVE IS MOVING THROUGH THE NW CARIBBEAN AND CENTRAL AMERICA ALONG 83W/84W S OF 23N MOVING W NEAR 20 KT. THIS WAVE HAS BECOME A LITTLE BETTER ORGANIZED TODAY WITH SFC OBS AND VISIBLE SATELLITE IMAGES SHOWING IMPROVED CURVATURE TO THE OVERALL STRUCTURE. CONVECTION HAS ALSO INCREASED SOME WITH SCATTERED MODERATE COVERING THE AREA WITHIN 150 NM EITHER SIDE OF THE WAVE AXIS. THE STRONGEST CLUSTER IS NEAR THE BASE OF THE WAVE...PULLED NWD FROM THE ITCZ...S OF 13N BETWEEN 76W-80W. A QSCAT PASS AROUND 11Z DEPICTED AN INCREASE IN ELY TRADES ALONG AND TO THE E OF THE WAVE. FURTHER DEVELOPMENT IS NO LONGER ANTICIPATED SINCE THE VORTICITY MAXIMUM IS OVER LAND. THE NRN PORTION OF A TROPICAL WAVE ALONG 94W EXTENDS ACROSS THE BAY OF CAMPECHE S OF 21N MOVING W 15-20 KT. THIS WAVE REMAINS WEAK WITH THE CURRENT PSN BASED MOSTLY ON A MODEST WWD SURGE OF MOISTURE...NOTED ON THE UW-CIMSS TPW PRODUCT. SHOWERS AND TSTMS ARE LIMITED. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 15N17W 11N25W 8N39W 12N50W 12N55W. BESIDES FOR THE CONVECTION DISCUSSED WITH THE TROPICAL WAVES...ISOLATED MODERATE IS WITHIN 180 NM EITHER SIDE OF THE AXIS BETWEEN 38W-44W AND FROM 6N-10N E OF 18W. ...DISCUSSION... THE GULF OF MEXICO... THE WEATHER ACROSS THE GULF IS QUIETER TODAY THAN THE PAST FEW DAYS AS THE OLD TRAILING FRONTAL BOUNDARY HAS NOW DISSIPATED AND A WEAK 1019 MB HIGH HAS DEVELOPED IN THE MID-GULF. STILL...SFC SWLY RETURN FLOW AND A WEDGE OF REMNANT UPPER MOISTURE IS SUPPORTING ISOLATED SHOWERS AND TSTMS ROUGHLY NW OF A LINE FROM NRN MEXICO TO THE FL BIG BEND AREA ALONG 23N98W 29N83W. DRY STABLE AIR ALOFT LIES ABOVE MUCH OF THE REMAINDER OF FLORIDA AND THE SE GULF BRINGING A SUNNY WARM/HOT SUMMER DAY. HOWEVER...RATHER ABUNDANT DEEP MOISTURE IS NOT FAR AWAY IN THE NW CARIB. THIS IS ASSOCIATED WITH THE NRN PART OF THE ACTIVE TROPICAL WAVE OVER CENTRAL AMERICA. SOME OF THIS MOISTURE SHOULD SPREAD INTO THE BAY OF CAMPECHE LATE TONIGHT AND TOMORROW AS THE WAVE CONTINUES W. SFC WINDS ARE LIGHT TO MODERATE AND FLOW ANTICYCLONICALLY AROUND THE AFOREMENTIONED HIGH NEAR 27N88W. THE CARIBBEAN SEA... THE MAIN FEATURE IN THE CARIB IS THE ACTIVE TROPICAL WAVE MOVING OVER CENTRAL AMERICA. FOR DETAILS REFER TO THE TROPICAL WAVES SECTION ABOVE. OTHERWISE...THIS REGION REMAINS RATHER TRANQUIL WITH UPPER NELY FLOW DRAWING DRIER AIR INTO MOST OF THE CENTRAL AND ERN PORTIONS. THE ATMOSPHERE IS A LITTLE MORE MOIST ACROSS THE NRN LEEWARD ISLANDS...CLOSER TO AN UPPER LOW CENTER. WSR-88D DATA FROM SAN JUAN SHOWS QUICK MOVING STREAMS OF SHOWERS HEADING TOWARD THE ISLAND FROM THE NE...LIKELY ASSOCIATED IN PART WITH THAT ACTIVITY. AN INCREASE IN MOISTURE IS LIKELY OVER THE NEXT COUPLE OF DAYS AS THE LARGE TROPICAL WAVE IN THE TROPICAL ATLC APPROACHES. TRADES ARE ON THE FRESH TO STRONG SIDE IN THE CENTRAL AND W CARIB N OF 12N W OF 70W...LIKELY ENHANCED SOME BY THE STRONG TROPICAL WAVE. THE ATLANTIC OCEAN... A STALLED FRONT LINGERS TO THE N OF OUR NRN BORDER ACROSS BERMUDA. ATTM...THIS BOUNDARY HAS LIMITED UPPER SUPPORT DUE TO A STRONG UPPER RIDGE CENTERED TO IT'S S NEAR 27N73W. HOWEVER...A SHORTWAVE ALONG THE U.S. E COAST SHOULD HELP GIVE THIS FRONT A KICK SHORTLY. THE UPPER RIDGE IS SUPPLYING THE BAHAMAS...FLORIDA AND THE SURROUNDING ATLC WATERS W OF 70W WITH FAIR WEATHER. DEBRIS MOISTURE...FROM THE ACTIVITY ALONG THE FRONT...IS GETTING PUSHED SWD BY STRONG NLY WINDS BETWEEN THE UPPER HIGH AND AN UPPER LOW NEAR 22N59W. THE INTERACTION BETWEEN THIS UPPER LOW AND A HIGH AMPLITUDE TROPICAL WAVE HAS ALSO SET UP SOME SHOWER ACTIVITY FROM 14N-26N BETWEEN 50W-59W...SEE ABOVE. THE REMAINDER OF THE UPPER PATTERN IS RATHER BENIGN WITH OVERALL LITTLE SIGNIFICANT MOISTURE BEING PRODUCED. THE SFC PATTERN IS DOMINATED BY A RIDGE EXTENDING FROM A 1028 MB HIGH NEAR 35N36W TO A 1020 MB CENTER NEAR 27N71W CONTINUING W INTO THE GULF. THE COMBINATION OF THIS HIGH PRES AND A LARGE AREA OF STABLE AIR ALOFT IS PRODUCING WIDESPREAD FAIR WEATHER N OF 18N E OF 50W. TYPICAL STABLE SCATTERED LOW-LEVEL STRATOCUMULUS ARE THE MAIN SOURCE OF CLOUD COVER ACROSS THIS REGION. TRADES ARE MODERATE...EXCEPT NEAR THE CARIB ISLANDS AND THE COAST OF NW AFRICA WHERE THE TIGHTENED PRES GRAD IS PRODUCING SLIGHTLY STRONGER WINDS. $$ CANGIALOSI