000 AXNT20 KNHC 152354 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST THU NOV 15 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 48W SOUTH OF 17N MOVING WEST 10-15 KT. CYCLONIC TURNING IS NOTED ALONG THE WAVE AXIS NEAR 10N. THE CIMSS 850 MB VORTICITY PRODUCT PROVIDES GOOD SUPPORT FOR THE WAVE POSITION INDICATED. THIS WAVE ALSO SHOWS UP IN THE TPW PRODUCT AS A LOW/MID AMPLITUDE MOISTURE SURGE. SCATTERED MODERATE CONVECTION IS MAINLY BEHIND WAVE AXIS FROM 8N-13N BETWEEN 43W-49W. A TROPICAL WAVE IS ALONG 71W SOUTH OF 20N MOVING WEST 10-15 KT. THE WAVE IS MOVING ACROSS HISPANIOLA AND WESTERN VENEZUELA GENERATING SCATTERED SHOWERS. A WELL DEFINED INVERTED-V LOW LEVEL CLOUD SIGNATURE IS NOTED ON SATELLITE IMAGERY. THE MIMIC-TPW ALSO SHOWS A GOOD SURGE OF MOISTURE ASSOCIATED WITH THIS FEATURE. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 10N14W 6N25W 7N40W 9N61W. BESIDES FOR THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVE...SCATTERED MODERATE CONVECTION IS FROM 2N-7N EAST OF 20W TO THE COAST OF W AFRICA. SIMILAR CONVECTION IS WITHIN 80-100 NM EITHER SIDE OF THE AXIS BETWEEN 30W-40W. DISCUSSION... THE GULF OF MEXICO... AS OF 2100 UTC...A FAST MOVING COLD FRONT EXTENDS FROM W-CENTRAL FLORIDA...ACROSS THE TAMPA BAY AREA INTO THE GULF TO JUST N OF VERACRUZ MEXICO. TAMPICO REPORTED A WIND GUST OF 40 KT AND LIGHT RAIN WITH THE PASSAGE OF THE FRONT. THE LEADING EDGE OF THE FRONT IS A VERY THIN LINE OF SCATTERED SHOWERS WITHIN 30 NM OF THE FRONT. 20-30 KT NLY WINDS ARE OVER THE NRN GULF OF MEXICO N OF THE FRONT. SFC OBSERVATIONS AND AN EARLIER ASCAT PASS CONFIRMED THESE WINDS. COLD AIR HAS PENETRATED INTO THE EASTERN SLOPES OF THE SIERRA MADRE MOUNTAINS AS DEPICTED BY RATHER UNIFORM LOW CLOUDS COVER WITH DRIZZLE/LIGHT RAIN JUST N OF VERACRUZ. THE REMAINDER OF THE GULF S OF THE FRONT HAS 10 KT NELY FLOW WITH FAIR WEATHER. IN THE UPPER LEVELS...A DEEP LAYERED TROUGH IS MOVING ACROSS THE EASTERN U.S WHILE A RIDGE DOMINATES THE MEXICO AND MOST OF THE GULF GIVING THE AREA W TO NW UPPER LEVEL WINDS. THIS UPPER TROUGH SUPPORTS THE ABOVE MENTIONED COLD FRONT THAT IS FORECAST TO MOVE ACROSS THE CENTRAL FLORIDA PENINSULA THIS EVENING AND THEN CONTINUE TO PASS THROUGH SOUTH FLORIDA OVERNIGHT USHERING A DRY AND COOL AIR MASS. THE CARIBBEAN SEA... THE COLD THAT IS CURRENTLY MOVING ACROSS THE GULF WILL REACH WESTERN CUBA/NW CARIBBEAN LATE TONIGHT INTO EARLY FRIDAY MORNING. HIGH PRES WILL BUILD BEHIND THE FRONT PRODUCING AN INCREASE IN WINDS AND SEAS OVER THE NW CARIBBEAN. A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL CARIBBEAN. SEE ABOVE. BROKEN TO OVERCAST LOW/MID CLOUDS WITH EMBEDDED SHOWERS AND ISOLATED TSTMS ARE AFFECTING THE WINDWARD ISLANDS...PARTICULARLY GRENADA...TRINIDAD AND TOBAGO. THIS ACTIVITY MAY BE ASSOCIATED WITH THE NORTHWARD MODULATION OF THE ITCZ DUE TO THE PRESENCE OF THE TROPICAL WAVE ALONG 71W. MOIST ONSHORE NE WINDS IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS ALONG THE COAST OF NICARAGUA AND COSTA RICA. UPPER DIFFLUENCE ASSOCIATED WITH AN UPPER LEVEL HIGH CENTERED OVER NICARAGUA IS ENHANCING THIS SHOWER ACTIVITY. SIGNIFICANT UPPER LEVEL MOISTURE AND HIGH CLOUDS ARE OVER THE SW CARIBBEAN AND CENTRAL AMERICA FROM PANAMA TO HONDURAS. A NEARLY ZONAL FLOW IS OVER THE E CARIBBEAN E OF 70W WITH A SHORT WAVE TROUGH OVER THE NE CARIBBEAN/LEEWARD ISLANDS. TRADE WINDS ARE EXPECTED TO INCREASE DURING THE UPCOMING WEEKEND AS HIGH PRES OVER THE N GULF WATERS MOVES EWD ACROSS THE W ATLC. THE NOAA WAVE-WATCH MODEL...NWW3...INDICATES E WINDS OF 20 TO 25 KT AND SEAS UP TO 9 FT. THE ATLANTIC OCEAN... A COLD FRONT IS ENTERING THE EXTREME NW PORTION OF THE AREA WITH A NARROW BAND OF LOW/MID CLOUDS WITH ISOLATED SHOWERS. THIS FRONT EXTENDS ACROSS N-CENTRAL FLORIDA AND THE GULF. ANOTHER COLD FRONT ENTERS THE AREA NEAR 31N27W THEN CONTINUES SW TO NEAR 22N50W. SCATTERED SHOWERS ARE WITHIN 90 NM OF THE FRONT. BETWEEN FRONTS...A 1026 MB HIGH PRES IS NEAR 35N49W COVERING MOST OF THE W-CENTRAL ATLC. A WEAK SFC LOW HAS DEVELOPED WITHIN 160 NM E OF THE CENTRAL BAHAMAS. A SWIRL OF LOW CLOUDS DEFINES THE LOW. THIS FEATURE IS FORECAST TO DISSIPATE WHILE BE ABSORBED BY THE APPROACHING COLD FRONT. IN THE UPPER LEVELS...A LONG WAVE TROUGH IS MOVING ACROSS THE EASTERN U.S. INTO THE W ATLC. A SHORT WAVE TROUGH IS ALONG 70N BETWEEN 24N-30N. AN AREA OF MULTILAYERED CLOUDS WITH SHOWERS AND SCATTERED TSTMS ARE AHEAD OF THIS TROUGH AFFECTING FROM 22N-32N BETWEEN 58W-68W. LIGHTNING DATA DEPICTS MOST OF TSTMS ACTIVITY NEAR 26N61W. UPPER DIFFLUENCE BETWEEN THIS TROUGH AND A RIDGE OVER THE CENTRAL ATLC IS HELPING TO INDUCE THIS ACTIVITY. ANOTHER UPPER-LEVEL TROUGH ENTERS THE FORECAST REGION NEAR 32N38W THEN EXTENDS TO 22N48W. DRY AIR IS NOTED ALONG THE TROUGH AXIS. AN UPPER RIDGE EXTENDING NEWD FROM THE TROPICAL ATLC NEAR 7N38W COVERS THE REMAINDER OF THE OCEAN AND NW AFRICA. $$ GR