000 AXNT20 KNHC 160517 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT FRI MAR 16 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0315 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 7N13W 4N20W 1N30W EQ40W 2N49W. SCATTERED SHOWERS AND TSTMS WERE MAINLY IN SMALL CLUSTERS MAINLY E OF 30W AND NEAR THE S AMERICAN COAST. ...DISCUSSION... GULF OF MEXICO... A WELL DEFINED SHORTWAVE WITH A MID/UPPER LEVEL LOW CENTER MOVING E 25 KT IS LOCATED OVER THE CENTRAL FL PANHANDLE. THE LOW IS EMBEDDED IN THE SRN BRANCH OF THE WESTERLIES. A SHORTWAVE IN THE NRN BRANCH IS DIVING SE OVER THE CENTRAL PLAINS TONIGHT AND IS BEGINNING TO INTERACT WITH THE SRN SHORTWAVE. THE TWO WILL CARVE OUT A LARGER SCALE MID LEVEL TROUGH ALONG THE E COAST DURING THE NEXT 24 HR. A WEAK SURFACE LOW VERY NEAR THE MID LEVEL LOW HAS A TROUGH EXTENDING SW OVER THE GULF. A VERY MOIST SLY FLOW PRESENT E OF THE TROUGH CONTINUES TO RESULT IN SCATTERED TSTMS OVER THE E GULF WHICH IS MOVING SE. THE REMAINDER OF THE GULF IS FAIRLY TRANQUIL UNDER MODERATE TO STRONG SUBSIDENCE AND ASSOCIATED DRY AIR ALOFT. CARIBBEAN... BROAD FLAT RIDGING COVERS MUCH OF THE CENTRAL AND ERN PORTIONS OF THE CARIBBEAN WITH UPPER LEVEL SW-W WINDS. MODERATE SUBSIDENCE AND ASSOCIATED DRY AIR IS EVIDENT ACROSS MOST OF THE REGION. IN THE LOWER LEVELS THE TAIL END OF A FRONTAL TROUGH EXTENDS SW FROM THE ATLANTIC SW TO THE LEEWARD ISLANDS. SLIGHT LOW-LEVEL CONVERGENCE NEAR THIS SLOWLY WEAKENING BOUNDARY IS PRODUCING PATCHES OF LOW AND MID LEVEL CLOUDS WITH ISOLATED SHOWERS. THE CLOUDINESS HAS BEEN MOVING NW IN MODERATE TO FRESH ELY TRADES. OVER THE NEXT COUPLE OF DAYS A STRONG SFC RIDGE WILL SHIFT EWD. THIS WILL ALLOW THE TRADE WINDS TO DECREASE ACROSS THE ERN CARIB. MEANWHILE A COLD FRONT IS FORECAST TO ENTER THE NW CARIBBEAN LATE FRI INTO SAT WITH SCATTERED SHOWERS AND TSTMS. THE FRONT IS THEN EXPECTED TO WEAKEN IN THE VICINITY OF THE WINDWARD PASSAGE SUN. WESTERN ATLANTIC... A STRONG ZONAL MID LEVEL PATTERN PERSISTS WITH AN EMBEDDED RIDGE ALONG 65W. AN AREA OF MID AND HIGH LEVEL CLOUDS IN THE RIDGE AXIS HAS SCATTERED EMBEDDED CONVECTION. THIS ACTIVITY IS ASSOCIATED WITH A SHORTWAVE TROUGH ALONG 70W IN THE MID LEVELS FOLLOWING THE RIDGE. THE AIR ALOFT IS VERY DRY BETWEEN 50W-55W WHERE UPPER CONFLUENCE IS QUITE STRONG. A LOW PRES SYSTEM WITH AN ASSOCIATED COLD FRONT ENTERS THE AREA NEAR 30N45W AND EXTENDS SW TO 24N50W WHERE IT THEN CONTINUES AS A WEAKENING SFC FRONTAL TROUGH TO THE NRN LEEWARD ISLANDS. SCATTERED SHOWERS AND TSTMS ARE WITHIN 180 NM AHEAD OF THE FRONT N OF 25N. ISOLATED TO SCATTERED SHOWERS ARE WITHIN 120 NM EITHER SIDE OF THE FRONTAL TROUGH. THE FRONT WILL CONTINUE E MAINTAINING CONVECTION WITH IT N OF 26N WHILE THE REMAINDER OF THE FRONTAL TROUGH DISSIPATE OVER THE NEXT 24 HRS. THE NEXT COLD FRONT IS EXPECTED TO MOVE OFF THE U.S. EAST COAST FRI NIGHT. EASTERN ATLANTIC... AN OPEN RIDGE WITH IT'S AXIS ALONG 38W IS MOVING SLOWLY EWD. MID AND HIGH LEVEL MOISTURE IS EVIDENT THROUGHOUT THE RIDGE. UPPER LEVELS QUICKLY DRY OUT E OF THE RIDGE WHERE THE MID LEVEL FLOW DIVES SE INTO A TROUGH ALONG 20W. A STRONG SFC HIGH CENTERED NEAR THE AZORES CONTINUES TO GENERATE A LARGE AREA OF MODERATE TO STRONG NE WINDS ACROSS THE REGION. IN THE DEEP TROPICS...THE UPPER LEVEL JETSTREAM BRANCH EXTENDS ANTICYCLONICALLY FROM THE WINDWARD ISLANDS TO 15N30W TO 10N24W. THE CENTER OF THE UPPER HIGH IS LOCATED NEAR 5N37W. ABUNDANT MOISTURE EXISTS S OF THE JET AXIS AND W OF 48W FED BY CONVECTION ALONG THE ITCZ NEAR THE S AMERICAN COAST. OVER THE NEXT COUPLE OF DAYS A SFC HIGH WILL SLOWLY RETREAT NWD BUT SHOULD REMAIN IN CONTROL MAINTAINING THE WIDESPREAD FAIR WEATHER. $$ RRG