000 AXNT20 KNHC 212356 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU JUN 21 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 31W/32W S OF 13N MOVING W NEAR 15 KT. ASSOCIATED NE-SE WIND SHIFT IS SEEN AT LOW LEVELS. THE SHOWER ACTIVITY REMAINS MINIMAL AND MOSTLY AHEAD OF THE WAVE AXIS EMBEDDED IN THE ITCZ. A TROPICAL WAVE IS ALONG 44W S OF 12N MOVING W 10 T0 15 KT. CONVECTION HAS SLIGHTLY INCREASE ALONG THE WAVE AXIS BUT NEAR THE ITCZ. A TROPICAL WAVE EXTENDS FROM HISPANIOLA TO WESTERN VENEZUELA ALONG 72W S OF 21N MOVING W NEAR 15 KT. THIS WAVE IS HELPING TO ENHANCE SOME SHOWER ACTIVITY OVER HISPANIOLA. A TROPICAL WAVE HAS BEEN ADDED ON THE 18Z MAP ALONG 81W/82W SOUTH OF 18N BASED ON THE PROPAGATION OF THE CONVECTION OBSERVED IN THE HOVMOLLER DIAGRAM. A 1009 MB LOW IS ALONG THE WAVE AXIS NEAR 11N. CURRENTLY...SATELLITE IMAGERY SHOWS A LARGE AREA OF DISTURBED WEATHER ASSOCIATED WITH THE WAVE AND THE LOW PRESSURE OVER THE WESTERN CARIBBEAN SEA AND PORTIONS OF CENTRAL AMERICA. WHILE CONDITIONS DO NOT APPEAR FAVORABLE FOR DEVELOPMENT...THIS SYSTEM COULD PRODUCE LOCALLY HEAVY RAINFALL OVER PORTIONS OF CENTRAL AMERICA DURING THE NEXT DAY OR SO AS IT MOVES SLOWLY WESTWARD. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 8N13W 7N30W 8N40W 8N50W 6N60W. SCATTERED MODERATE CONVECTION IS FROM 4N-10N BETWEEN 35W-46W. CLUSTERS OF MODERATE CONVECTION ARE SEEN FROM FRENCH GUIANA TO EASTERN VENEZUELA. ...DISCUSSION... THE GULF OF MEXICO... WEAK LOW PRES TROUGHING COVERS THE E GULF ASSOCIATED WITH A SLOW MOVING 1013 MB FRONTAL LOW CENTERED ABOUT 50 MILES SOUTHEAST OF JACKSONVILLE FLORIDA. DOPPLER RADAR SHOWS LINES OF SCATTERED SHOWERS AND TSTMS MOVING SOUTH OVER N-CENTRAL FLORIDA ASSOCIATED WITH THE CIRCULATION OF THE LOW. MODEST RIDGING COVERS THE REMAINDER OF THE GULF. THIS OVERALL WEAK PRES PATTERN IS PROVIDING THE AREA WITH LIGHT WINDS AND LOW SEAS. ALOFT...THE FLOW IS PRIMARILY NLY ON THE ERN PERIPHERY OF A HIGH CENTERED OVER WEST-CENTRAL MEXICO NEAR 20N100W. THESE WINDS ARE ADVECTING ABUNDANT UPPER LEVEL MOISTURE OVER THE WESTERN GULF. A WEAK TROUGH ALONG 87W/88W IS INTERRUPTING THE RIDGING ALLOWING MOST OF THE UPPER FLOW TO BE LIGHT IN ITS VICINITY. NWP MODELS GENERALLY SHOW LITTLE MOVEMENT OF THE LOW OR REMNANT TROUGH WHILE THE WEAK RIDGE OF HIGH PRES OVER NW GULF WILL PERSIST TROUGH THE WEEKEND. THIS WILL ALLOW THE SFC FLOW TO REMAIN LIGHT FOR A COUPLE OF DAYS MORE. THEREAFTER...SFC WINDS AND MOISTURE MAY INCREASE ACROSS THE SRN WATERS AS THE NRN EXTENSION OF THE W CARIB TROPICAL WAVE APPROACHES. THE CARIBBEAN SEA... CLUSTERS OF MODERATE TO STRONG CONVECTION ARE OVER THE WESTERN CARIBBEAN AND PARTS OF CENTRAL AMERICA ASSOCIATED WITH A TROPICAL WAVE AND A BROAD AREA OF LOW PRESSURE. DIFFLUENCE ASSOCIATED WITH AN UPPER HIGH LOCATED NEAR 12N80W IS ENHANCING THIS CONVECTIVE ACTIVITY. ANOTHER TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN. SEE TROPICAL WAVES SECTION. ALOFT...AN UPPER HIGH REMAINS E OF THE WINDWARD ISLANDS NEAR 12N55W WITH A RIDGE EXTENDING WWD TO 70W. THIS RIDGE IS GIVING THE REGION UPPER DRY AIR/SUBSIDENCE. WLY UPPER WINDS DOMINATES THE AREA N OF 17N EAST OF 80W. THESE WINDS ARE TRANSPORTING ABUNDANT UPPER LEVEL MOISTURE ACROSS THE NORTHERN CARIBBEAN INTO THE ATLANTIC OCEAN BEYOND 55W. 20 TO 30 KT TRADE WINDS ARE BLOWING ACROSS THE BASIN. THESE STRONG WINDS ARE ANTICIPATED TO PERSIST AND EXPAND SLIGHTLY WWD OVER THE NEXT COUPLE DAYS AS THE ATLC RIDGE N OF THE AREA STRENGTHENS. THE ATLANTIC OCEAN... A 1013 MB FRONTAL LOW IS SITUATED APPROXIMATELY 50 MILES SOUTHEAST OF JACKSONVILLE FLORIDA. DISORGANIZED SHOWERS AND THUNDERSTORMS ARE ASSOCIATED WITH THIS FEATURE. THERE ARE NO SIGNS OF ORGANIZATION AND UPPER LEVEL WINDS ARE NOT FAVORABLE FOR DEVELOPMENT. FARTHER EAST...AN UPPER TROUGH CUTS ACROSS THE AREA FROM 32N62W SW TO THE SE BAHAMAS. STRONG SWLY WINDS AHEAD OF THE TROUGH AXIS ARE SHEARING THE TROPICAL WAVE NOW LOCATED OVER HISPANIOLA. OTHERWISE...A SFC HIGH PRES RIDGE IS IN CONTROL OF THE E-CENTRAL ATLC RUNNING FROM A 1029 MB HIGH S OF THE AZORES NEAR 36N25W TO A 1022 MB CENTER NEAR 25N55W. THIS RIDGE IS ALLOWING WINDS TO BE LIGHT TO MODERATE ACROSS MOST OF THE ATLC DISCUSSION AREA. THE EXCEPTION IS NEAR THE AFRICAN COAST WHERE THE PRES GRADIENT IS TIGHTENED BETWEEN THE AZORES HIGH AND INVERTED TROUGHING OVER THE CONTINENT. NE WINDS OF 20 TO 25 KT ARE SEEN E OF 25W FROM THE CAPE VERDE ISLANDS TO THE MADEIRA AND CANARY ISLANDS. THE COMBINATION OF THIS HIGH PRES ALONG WITH DRY STABLE AIR ALOFT ASSOCIATED WITH AN UPPER RIDGE ALONG 24W/25W IS PROVIDING TRANQUIL CONDITIONS ACROSS THE E AND MOST OF THE TROPICAL ATLC WITH ONLY PATCHES OF LOW/MID CLOUDS. $$ GR