000 AXNT20 KNHC 312354 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI OCT 31 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. ...THE ITCZ... ITCZ AXIS IS ANALYZED ALONG 10N14W 11N23W 8N35W 9N50W 11N62W. TWO SURFACE TROUGHS REMAIN EMBEDDED WITHIN THE ITCZ...ONE IS JUST SOUTH OF THE CAPE VERDE ISLANDS ALONG 24W AND IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS. THIS TROUGH SHOWS UP ON THE TPW PRODUCT FROM CIMSS WHERE A BULGE OF MOISTURE IS SEEN. THE SECOND ONE IS ALONG 45W. A LARGE AREA OF DISORGANIZED SHOWERS AND THUNDERSTORMS ACCOMPANIES THIS TROUGH AND COVERS FROM 8N-14N BETWEEN 40W-48. UPPER DIFFLUENCE IS ENHANCING THIS CONVECTIVE ACTIVITY. ELSEWHERE...ANOTHER LARGE AREA OF MODERATE TO ISOLATED STRONG CONVECTION IS INLAND OVER WEST AFRICA FROM 8N-12N BETWEEN 10W-14W. SCATTERED MODERATE CONVECTION IS NEAR 6N22W...12N32.5W...AND WITHIN 115 NM N OF AXIS BETWEEN 34W-36W. ...DISCUSSION... GULF OF MEXICO... WEATHER CONDITIONS ACROSS THE GULF REGION HAVE EXPERIENCED LITTLE CHANGE SINCE YESTERDAY. A SURFACE RIDGE ANCHORED ON A 1035 MB HIGH OVER THE CAROLINAS DOMINATES THE ENTIRE REGION. THE RIDGE ALSO ENVELOPS THE W ATLANTIC...MUCH OF CUBA...THE NW CARIBBEAN AND THE YUCATAN PENINSULA. COLD AIR STRATOCUMULUS CLOUDS ARE NOTED OVER MUCH OF THE AREA. THE E GULF AND FLORIDA PENINSULA IS DOMINATED BY MODERATE/STRONG SUBSIDENCE WHICH IS LIMITING ANY DEEP CONVECTIVE ACTIVITY. NE WINDS OF 20 KT ARE BLOWING OVER THE SE PORTION OF THE GULF DUE TO TIGHT PRES GRADIENT BETWEEN THE ABOVE MENTIONED HIGH PRES AND LOWER PRES OVER THE SW CARIBBEAN. THE REMAINDER OF THE GULF HAS WINDS OF 10 TO 15 KT. THIS HIGH PRES SYSTEM OVER THE CAROLINAS IS FORECAST TO WEAKEN THROUGH THE WEEKEND ALLOWING WINDS TO DIMINISH ACROSS GULF WATERS. ALOFT...A MAINLY ZONAL FLOW DOMINATES THE GULF BUT THIS PATTERN IS EXPECTED TO CHANGE DURING THE WEEKEND AS A SHORT WAVE TROUGH AMPLIFIES AND BECOMES A CLOSED LOW OVER THE LOWER MISSISSIPPI VALLEY. THE ASSOCIATED UPPER-LEVEL TROUGH WILL DIG INTO THE CENTRAL GULF AND MOVES SLOWLY EWD. CARIBBEAN SEA... THE REMNANTS OF A FRONTAL BOUNDARY CONTINUES TO PRODUCE A BAND OF SHOWERS WITH ISOLATED TSTMS FROM THE WINDWARD PASSAGE/E CUBA TO OVER JAMAICA AND NORTHERN HONDURAS. AN EARLIER ASCAT SHOWED MODERATE TO STRONG NE WINDS OF 20 TO 25 KT OVER THE NW CARIBBEAN BEHIND THE REMNANTS OF THE FRONT. SCATTERED MODERATE CONVECTION IS OVER THE SW CARIBBEAN WHILE ISOLATED SHOWERS DOT THE REMAINDER OF THE CARIBBEAN USHERED IN ON MODERATE TO STRONG EASTERLY TRADE WINDS. AN AREA OF LOW LEVEL MOISTURE WITH EMBEDDED SHOWERS IS MOVING WWD ACROSS THE NE CARIBBEAN AFFECTING THE NORTHERN LEEWARD ISLANDS AND THE VIRGIN ISLANDS. THIS ACTIVITY WILL REACH EASTERN PUERTO RICO LATER THIS EVENING. IN THE UPPER LEVELS...THE BASIN IS DOMINATED BY AN UPPER RIDGE CENTERED OVER THE GULF OF HONDURAS. WLY WINDS ON THE NORTHERN SIDE OF THIS RIDGE ARE NOTED OVER CUBA. THIS RIDGE IS SUPPORTING CONVECTION ALONG THE REMNANTS OF THE FRONT AND OVER THE SW CARIBBEAN. SCATTERED MODERATE CONVECTION IS ALSO OVER PARTS OF PANAMA AND COSTA RICA LIKELY DUE TO THE CLOSE PROXIMITY OF THE EPAC ITCZ. ATLANTIC OCEAN... A DEEP LAYERED TROUGH PERSISTS OVER THE WRN ATLC WHILE THE RIDGE OVER THE CARIBBEAN SEA EXTENDS NE THROUGH THE N LEEWARD ISLANDS INTO THE CENTRAL ATLC. A BAND OF MULTILAYERED CLOUDS WITH EMBEDDED SHOWERS LIES BETWEEN THESE TWO UPPER-LEVEL FEATURES AND EXTENDS FROM EASTERN CUBA/WINDWARD PASSAGE ALL THE WAY NE TO BEYOND 32N54W. AT THE SURFACE...A FRONTAL BOUNDARY AND A SFC TROUGH IS ASSOCIATED WITH THIS BAND OF CLOUDS. HIGH PRES SITUATED OVER THE CAROLINAS EXTENDS A RIDGE OVER THE W ATLC AND THE BAHAMAS. BROKEN COLD AIR STRATOCUMULUS CLOUDS AND NE WINDS OF 20 TO 25 KT COVER THIS AREA. THESE WINDS ARE ADVECTING PATCHES OF LOW LEVEL MOISTURE WITH ISOLATED SHOWERS ACROSS FLORIDA. A NARROW UPPER-LEVEL TROUGH IS IN THE CENTRAL ATLC EXTENDING FROM NEAR 25N45W INTO THE TROPICS TO NEAR 8N50W. SUBSIDENCE/DRY AIR BEHIND THIS UPPER TROUGH DOMINATES THE TROPICS BETWEEN 50W AND THE LESSER ANTILLES. A BROAD UPPER-LEVEL TROUGH ENTERS THE FORECAST AREA THROUGH THE MADEIRA/CANARY ISLANDS. THE ATTENDANT COLD FRONT IS APPROACHING THE CANARY ISLANDS WHERE WLY WINDS OF 15 TO 20 KT ARE BLOWING. AN E/W UPPER RIDGE COVERS THE REMAINDER OF THE TROPICAL ATLC ANCHORED OFF THE COAST OF W AFRICA NEAR 11N23W. THE UPPER DIFFLUENCE ASSOCIATED WITH THIS UPPER RIDGE IS AIDING IN SUPPORTING THE CONVECTION ASSOCIATED WITH THE SURFACE TROUGHS EMBEDDED WITHIN THE ITCZ. OF NOTE...NOVEMBER IS THE LAST MONTH OF THE ATLANTIC HURRICANE SEASON. SO FAR...FIFTEEN NAMED STORMS HAVE DEVELOPED...OF WHICH SEVEN BECAME HURRICANES...WITH FOUR OF THE HURRICANES ATTAINING MAJOR HURRICANE STATUS. IN ADDITION...A SHORT LIFE TROPICAL DEPRESSION FORMED IN OCTOBER. THE MOST POWERFUL HURRICANES SEEN THIS SEASON ARE GUSTAV AND IKE...BOTH CAT 4 ON THE SAFFIR SIMPSON SCALE. $$ GR