000 AXNT20 KNHC 011055 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SAT NOV 01 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0945 UTC. ...THE ITCZ... ITCZ AXIS IS ANALYZED ALONG 10N12W 9N20W 12N35W 10N52W 10N63W. TWO SURFACE TROUGHS REMAIN EMBEDDED WITHIN THE ITCZ. ONE TROUGH EXTENDS FROM SW OF THE CANARY ISLANDS NEAR 15N27W TO 11N28W TO 7N29W. THIS TROUGH COINCIDES WITH BOTH A WESTWARD-MOVING SURGE IN DEEP LAYER MOISTURE BASED ON TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS...AND A MAXIMUM IN LOW LEVEL CYCLONIC CIRCULATION BASED ON CIMSS WAVETRAK PRODUCT. SCATTERED MODERATE CONVECTION IS WITHIN 210 NM EITHER SIDE OF THE TROUGH N OF 12N...WHICH IS BEING ENHANCED BY UPPER LEVEL DIVERGENCE. THE SECOND TROUGH EXTENDS FROM 17N47W TO 14N48W TO 10N48W AND COINCIDES WITH ANOTHER WESTWARD-MOVING SURGE IN DEEP LAYER MOISTURE. MOST OF THE CONVECTION ASSOCIATED WITH THIS TROUGH IS CURRENTLY TO ITS EAST...WITH SCATTERED MODERATE CONVECTION FROM 12N-17N BETWEEN 31W-46W. THIS CONVECTION IS BEING ENHANCED BY UPPER LEVEL DIVERGENCE IN THE PRESENCE OF DEEP MOISTURE. ELSEWHERE... SCATTERED MODERATE CONVECTION IS OCCURRING WITHIN 60 NM N AND S OF ITCZ AXIS BETWEEN 14W-24W. ADDITIONALLY...AN EAST-TO-WEST SURFACE TROUGH IS S OF THE ITCZ AXIS W OF THE W COAST OF AFRICA...AND EXTENDS FROM 6N12W TO 4N18W TO 5N25W. LOW LEVEL CONVERGENCE NEAR THIS TROUGH IS SUPPORTING SCATTERED MODERATE CONVECTION WITHIN 150 NM N AND S OF THIS FEATURE. ...DISCUSSION... GULF OF MEXICO... A SURFACE RIDGE OF HIGH PRESSURE IS AFFECTING MUCH OF THE GULF REGION. THIS SURFACE RIDGE IS ANCHORED BY A 1031 MB SURFACE HIGH OVER THE SE CONUS. SUBSIDENCE IN THE VICINITY OF THE RIDGE IS RESULTING IN FAIR WEATHER CONDITIONS ACROSS MUCH OF THE GULF REGION. ALOFT...UPPER LEVEL MOISTURE IS EMBEDDED WITHIN THE BASE OF AN UPPER LEVEL TROUGH THAT COVERS MUCH OF THE GULF...AND IS RESULTING IN HIGH CLOUDINESS OVER THE SE GULF. ACROSS THE N AND W GULF...DEEP LAYER DRY AIR AND STRONG MID/UPPER-LEVEL WESTERLY AND NORTHWESTERLY FLOW ARE PRESENT. THE UPPER LEVEL PATTERN IS FORECAST TO CHANGE OVER THE NEXT DAY AS A CLOSED UPPER LEVEL LOW AND ASSOCIATED UPPER TROUGH AND UPPER MOISTURE...CURRENTLY CENTERED OVER N MISSISSIPPI...APPROACH THE N GULF. HOWEVER... COMPUTER MODEL GUIDANCE INDICATES THAT THESE FEATURES COULD TEMPORARILY WEAKEN AS THEY BECOME OVERTAKEN BY AN EASTWARD-MOVING UPPER RIDGE CURRENTLY OVER THE PLAINS OF THE CONUS. ADDITIONALLY...STRONG N TO NE SURFACE WINDS ARE BLOWING THROUGH THE ISTHMUS OF TEHUANTEPEC RESULTING IN GALE FORCE WINDS IN THE E PACIFIC REGION. CARIBBEAN SEA... ANTICYCLONIC FLOW AROUND AN UPPER HIGH CENTERED NEAR 15N72W COVERS MUCH OF THE CARIBBEAN...WITH DEEP MOISTURE OVER THE W CARIBBEAN. UPPER LEVEL DIVERGENCE SW OF THE UPPER HIGH IS SUPPORTING SCATTERED MODERATE/ISOLATED STRONG CONVECTION OVER THE W CARIBBEAN FROM 9N-18N BETWEEN 76W-84W...AFFECTING PORTIONS OF PANAMA...COSTA RICA...AND N COLOMBIA...WHERE LOW LEVEL CONVERGENCE NEAR THE E PACIFIC ITCZ IS ENHANCING THE CONVECTION. ADDITIONALLY...A SURFACE TROUGH EXTENDS FROM E CUBA NEAR 20N75W TO 18N79W TO NE NICARAGUA NEAR 15N84W. A RECENT ASCAT PASS DEPICTS NE WINDS OF 15 TO 20 KT NW OF THE SURFACE TROUGH...AND NE TO E WINDS OF 10 TO 15 KT SE OF THE SURFACE TROUGH. THE CORRESPONDING LOW LEVEL CONVERGENCE NEAR THIS TROUGH...COMBINED WITH DEEP MOISTURE...IS SUPPORTING ISOLATED MODERATE CONVECTION WITHIN 60 NM EITHER SIDE OF THE SURFACE TROUGH. DEEP LAYER DRY AIR E OF THE UPPER HIGH IS RESULTING IN MAINLY FAIR WEATHER ACROSS THE E CARIBBEAN. ATLANTIC OCEAN... DEEP LAYER DRY AIR IS EMBEDDED WITHIN A BROAD UPPER LEVEL TROUGH OVER THE W ATLC...WHERE GENERALLY FAIR WEATHER IS PRESENT. AT THE SAME TIME...A SURFACE RIDGE OF HIGH PRESSURE...ANCHORED BY A 1031 MB SURFACE HIGH OVER THE SE CONUS...IS RESULTING IN SUBSIDENCE ACROSS MUCH OF THE W ATLC. FARTHER TO THE E...A SURFACE STATIONARY FRONT EXTENDS FROM 32N53W TO 29N57W TO 25N63W...AND A SURFACE TROUGH EXTENDS FROM 25N63W TO 22N70W TO E CUBA NEAR 20N75W. ATMOSPHERIC LIFT IN MOIST SOUTHWESTERLY FLOW ALOFT IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THE SURFACE STATIONARY FRONT AND SURFACE TROUGH...WHICH ARE BEING SUPPORTED BY UPPER DIFFLUENCE NEAR AN UPPER RIDGE FROM 22N-30N BETWEEN 48W-58W. FARTHER TO THE E...A COMPACT UPPER LEVEL TROUGH IS PRESENT WITH AN AXIS THAT EXTENDS FROM 27N48W TO 16N49W TO 10N48W. ALSO...A DEEP LAYER TROUGH IS N OF 21N E OF 41W...WHICH IS SUPPORTING A SURFACE COLD FRONT EXTENDING FROM 32N9W TO 28N18W TO 32N30W THAT IS MOVING SOUTHWARD ACROSS THE CANARY ISLANDS. ISOLATED SHOWERS ARE OCCURRING WITHIN 60 NM EITHER SIDE OF THE COLD FRONT E OF 16W. OVER THE TROPICAL ATLC...AN EAST-TO-WEST UPPER RIDGE IS ALONG 11N BETWEEN THE AFRICAN COAST AND 43W. UPPER LEVEL DIVERGENCE NEAR THIS RIDGE IS ENHANCING THE CONVECTION ASSOCIATED WITH THE SURFACE TROUGHS THAT ARE 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-LIVED TROPICAL DEPRESSION FORMED IN OCTOBER. THE MOST POWERFUL HURRICANES SEEN THIS SEASON ARE GUSTAV AND IKE...BOTH CAT 4 ON THE SAFFIR SIMPSON SCALE. $$ COHEN/GR