000 AXNT20 KNHC 302345 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU OCT 30 2008 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND 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 EXTENDS FROM DOMINICAN REPUBLIC TO WESTERN VENEZUELA ALONG 70W/71W MOVING W 10-15 KT. AN INVERTED-V LOW-LEVEL CLOUD SIGNATURE IS OBSERVED ON VIS SATELLITE IMAGERY. THE WAVE COUPLE WITH A DISSIPATING FRONTAL BOUNDARY IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS OVER HISPANIOLA. ISOLATED SHOWERS ARE SEEN OVER WESTERN VENEZUELA INCLUDING THE LAKE MARACAIBO AREA. ...THE ITCZ... ITCZ AXIS IS ANALYZED ALONG 7N12W 8N22W 7N30W 11N43W 9N50W INTO NE VENEZUELA. TWO SURFACE TROUGHS ARE EMBEDDED WITHIN THE ITCZ...ONE JUST SOUTH OF THE CAPE VERDE ISLANDS ALONG 24W WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 11N-13N BETWEEN 19W-23W...THE SECOND IS ALONG 43W FROM 10N-17N. CONVECTION ASSOCIATED WITH THIS SECOND TROUGH HAS SLIGHTLY INCREASED THIS EVENING. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 10N-16N BETWEEN 40W-46W. SIMILAR CONVECTION IS ALSO NOTED FROM 5N-10N BETWEEN 32W-38W. ...DISCUSSION... GULF OF MEXICO... THE GULF REGION REMAINS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED ON A 1033 MB HIGH OVER THE CAROLINAS. SCATTERED TO BROKEN COLD AIR STRATOCUMULUS CLOUDS COVER MUCH OF THE AREA BUT PARTICULARLY THE SE GULF. THESE CLOUDS ARE MOVING TOWARD THE YUCATAN PENINSULA UNDER A NELY WIND FLOW. THE NE CORNER OF THE GULF IS MOSTLY CLEAR THIS EVENING. ALOFT..A MAINLY ZONAL FLOW DOMINATES THE GULF WITH A JET STREAM BRANCH CROSSING THE CENTRAL GULF AND SOUTH FLORIDA WHERE SOME HIGH CLOUDS ARE SEEN. DENSE LOW STRATUS CLOUDS AND ISOLATED SHALLOW SHOWERS ARE BANKING ALONG THE ERN SLOPES OF THE SIERRA MADRE MOUNTAIN AND ADJACENT COASTAL WATERS INCLUDING ALSO THE BAY OF CAMPECHE. THE CITY OF VERACRUZ HAS REPORTED LIGHT RAIN DURING THE PAST FEW HOURS. THE GFS COMPUTER MODEL SUGGESTS A WIND SURGE ACROSS THE STRAITS OF FLORIDA AND THE SE GULF LATE TONIGHT THROUGH SATURDAY LIKELY ASSOCIATED WITH A TIGHT PRES GRADIENT BETWEEN THE HIGH PRES OVER THE CAROLINAS AND LOWER PRES OVER THE SW CARIBBEAN. BREEZY CONDITIONS ARE EXPECTED IN SOUTH FLORIDA ON FRI. CARIBBEAN SEA... A WEAKENING STATIONARY FRONT ENTERS THE CARIBBEAN SEA FROM THE W ATLC ACROSS FAR NW HISPANIOLA TO OVER JAMAICA ENDING NEAR CABO GRACIAS A DIOS NICARAGUA. THIS BOUNDARY CONTINUES TO PRODUCE SCATTERED SHOWERS/ISOLATED TSTMS WITHIN 60 NM ON EITHER SIDE OF THE FRONT. NELY WINDS OF 20 TO 25 KT ARE STILL BLOWING BEHIND THE FRONTAL BOUNDARY WHILE MODERATE TRADE WINDS OF 15 TO 20 KT ARE OVER THE REMAINDER OF THE REGION. A TROPICAL WAVE IS GENERATING SOME SHOWER ACTIVITY OVER HISPANIOLA. HIGH PRES SITUATED OVER THE CAROLINAS ALSO ENVELOPS MOST OF CUBA AND THE NW CARIBBEAN. NE WINDS AROUND THE PERIPHERY OF THIS SYSTEM ARE TRANSPORTING COLD AIR STRATOCUMULUS CLOUDS FROM THE W ATLC ACROSS THE BAHAMAS INTO CUBA AND THE NW CARIBBEAN. LOW-TOPPED TRADE WIND SHOWERS ARE MOVING WWD ACROSS THE EASTERN AND CENTRAL CARIBBEAN INCLUDING PUERTO RICO AND THE VIRGIN ISLANDS. ALOFT... THE BASIN IS DOMINATED BY AN UPPER RIDGE EXTENDING FROM THE E PACIFIC ACROSS CENTRAL AMERICA WITH A RIDGE AXIS EXTENDING ALONG 16N. WLY WINDS ON THE NORTHERN SIDE OF THIS RIDGE ARE NOTED OVER CUBA. THIS RIDGE IS ENHANCING CONVECTION ALONG THE FRONTAL BOUNDARY AND OVER THE SW CARIBBEAN. LOW-LEVEL WIND/SPEED CONVERGENCE IS PRODUCING SCATTERED MODERATE CONVECTION ALONG THE CARIBBEAN PLAINS OF NICARAGUA AND NORTHERN COSTA RICA. ATLANTIC OCEAN... A BROAD DEEP LAYERED TROUGH IS OVER THE W ATLC WITH A WEAKENING JETSTREAM OF WINDS 60 TO 75 KT FROM SRN FLORIDA TO BEYOND 31N65W. THIS UPPER TROUGH SUPPORTS A COLD FRONT THAT CLIPS THE W ATLC N OF 28N AND WEST OF 75W. A DISTINCT WIND SHIFT WITH STRATOCUMULUS CLOUDS ACCOMPANIES THIS FRONT. FARTHER EAST...A STATIONARY FRONT ENTERS THE DISCUSSION AREA NEAR 32N57W EXTENDING SW TO NORTHERN HAITI INTO THE CARIBBEAN SEA WHERE IS DISSIPATING. SCATTERED SHOWERS AND ISOLATED TSTMS ARE ALONG THE FRONTAL BOUNDARY. AN UPPER-LEVEL RIDGE EXTENDS FROM THE CARIBBEAN SEA THROUGH PUERTO RICO INTO THE CENTRAL ATLC WHILE AN UPPER-LEVEL TROUGH DIGS INTO THE TROPICS BETWEEN 50W AND THE LESSER ANTILLES. SUBSIDENCE/DRY AIR BEHIND THE UPPER TROUGH DOMINATES THE TROPICAL N ATLANTIC. MOSTLY ZONAL UPPER-LEVEL FLOW IS IN CONTROL OF THE E ATLC N OF THE CAPE VERDE ISLANDS. AN E/W UPPER RIDGE COVERS THE REMAINDER OF THE TROPICAL ATLC ANCHORED OFF THE COAST OF W AFRICA NEAR 9N23W. THE UPPER DIFFLUENCE ASSOCIATED WITH THIS UPPER RIDGE IS AIDING IN SUPPORTING THE CONVECTION ASSOCIATED WITH THE SURFACE TROUGHS EMBEDDED WITHIN THE ITCZ. $$ GR