000 AXNT20 KNHC 281031 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT TUE OCT 28 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. ...TROPICAL WAVES... TROPICAL WAVE WAS RELOCATED ALONG 47W/48W S OF 17N MOVING W 10-15 KT BASED ON LONG TERM SATELLITE IMAGERY. MID LEVEL INVERTED-V CURVATURE IS OBSERVED WITHIN SCATTERED MODERATE/ ISOLATED STRONG CONVECTION FROM 11N-16N BETWEEN 44W-50W. TROPICAL WAVE IS ALONG 58W/59W FROM 10N-18N MOVING W 10 KT. A WELL DEFINED INVERTED-V CURVATURE IS OBSERVED ON SATELLITE IMAGERY WITH CLUSTERS OF SCATTERED MODERATE CONVECTION FROM 14N-18N BETWEEN 57W-61W. ...THE ITCZ... ITCZ AXIS IS ANALYZED ALONG 11N14W 6N29W 13N43W 8N58W. A SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ ALONG 38W/39W FROM 6N-16N. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE WITHIN 120 NM EITHER SIDE OF THE ITCZ E OF 23W TO INLAND OVER W AFRICA AND WITHIN 225 NM EITHER SIDE OF THE ITCZ BETWEEN 23W-41W. ...DISCUSSION... GULF OF MEXICO... A DEEP LAYERED TROUGH COVERS THE E US AND INTO THE GULF N OF 25N WITH A JET STREAM OF 90 TO 120 KT OVER THE NE GULF. THE ASSOCIATED FAST MOVING COLD FRONT ENTERS THE GULF ACROSS THE FLORIDA KEYS TO THE N COAST OF THE YUCATAN PENINSULA TO MEXICO NEAR TUXPAN. A SURFACE RIDGE CONTINUES TO BUILD BEHIND THE FRONT ANCHORED BY A SERIES OF HIGHS OVER THE CENTRAL PLAIN STATES. THE AIR MASS N OF THE FRONT REMAINS RATHER DRY WITH DEW POINTS ALONG THE N GULF COAST DOWN TO THE 20 TO 30 DEGREE RANGE AND TEMPERATURES DROPPING INTO THE 40 TO 50 DEGREE RANGE. LOW CLOUDS WITH ISOLATED SHOWERS DELINEATE THE FRONT AS THE AIR MASS REMAINS DRIER BY THE PREVIOUS FRONTAL PASSAGE. COLD AIR STRATOCUMULUS CLOUDS ARE DEVELOPING BEHIND THE FRONT AS WELL AS STRONG NORTHERLY WINDS. THE S GULF IS DOMINATED BY SW UPPER WINDS WHICH IS ADVECTING UPPER MOSITURE FROM THE E PACIFIC REGION ACROSS MEXICO TO OVER THE SW GULF MAINLY IN THE FORM OF THIN HIGH CLOUDS. THE FRONT IS EXPECTED TO CLEAR THE ENTIRE GULF LATER TODAY. CARIBBEAN SEA... THE REMNANTS OF A FRONTAL BOUNDARY REMAINS IN THE NW CARIBBEAN EXTENDING ACROSS CUBA NEAR 22N80W TO THE GULF OF HONDURAS NEAR ROATAN ISLAND. THIS FRONT CONTINUES TO PRODUCE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 75 NM SE OF THE FRONT AND ISOLATED SHOWERS WITHIN 45 NM NW OF THE FRONT. THE UPPER LEVELS OF THE CARIBBEAN ARE DOMINATED BY AN UPPER RIDGE ANCHORED IN THE W ATLC N OF PUERTO RICO GIVING THE CARIBBEAN E OF THE FRONT STRONG SUBSIDENCE AND DRY STABLE AIR. THE REMNANTS OF A SURFACE TROUGH EXTENDS FROM 19N62W ACROSS PUERTO RICO AND ALONG THE S COAST OF THE DOMINICAN REPUBLIC GENERATING LOW LEVEL ISOLATED SHOWERS WITHIN 90 NM EITHER SIDE OF THE TROUGH. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 75 NM ALONG THE COAST OF COLOMBIA TO COSTA RICA. OTHERWISE THE REMAINDER OF THE CARIBBEAN IS TRANQUIL THIS MORNING. ATLANTIC OCEAN... A DEEP LAYERED TROUGH THAT COVERS THE E US EXTENDS OVER THE W ATLC W OF 70W WITH A WEAK COLD FRONT ENTERING THE REGION NEAR 32N66W ALONG 26N71W ACROSS THE BAHAMAS AND INTO THE NW CARIBBEAN NEAR 22N80W WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 90 NM E OF THE FRONT. A SECOND STRONGER AND FASTER MOVING COLD FRONT ENTERS THE W ATLC NEAR 32N74W AND INTO THE GULF OF MEXICO ACROSS THE FLORIDA KEYS. DENSE LOW LEVEL CLOUDS WITH POSSIBLE ISOLATED SHOWERS ARE WITHIN 150 NM N OF THE STRONG FRONT TO 80W. THESE FRONTS ARE EXPECTED TO MERGE LATE TODAY INTO TONIGHT. BROAD UPPER RIDGE COVERS THE REMAINDER OF THE W ATLC AND INTO THE CENTRAL ATLC ANCHORED N OF PUERTO RICO NEAR 22N65W WITH ENOUGH UPPER DIFFLUENCE OVER THE CENTRAL ATLC TO GENERATE SCATTERED SHOWERS E OF 55W TO A SURFACE TROUGH IN THE CENTRAL ATLC EXTENDING FROM 31N47W TO 18N53W. A NARROW UPPER LEVEL SHEAR AXIS EXTENDS INTO THE CENTRAL ATLC NEAR 32N41W S TO 22N43W THEN SW TO THE COAST OF SOUTH AMERICA NEAR 9N60W. THIS SHEAR AXIS IS ENHANCING THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVE ALONG 58W/59W. A STRONG UPPER RIDGE COVERS THE REMAINDER OF THE TROPICAL ATLC ANCHORED NEAR 10N27W AND COVERS THE AREA S OF 26N E OF THE CENTRAL ATLC SHEAR AXIS. THE UPPER DIFFLUENCE ASSOCIATED WITH THIS UPPER RIDGE IS GENERATING THE CONVECTION SURROUNDING THE SURFACE TROUGH EMBEDDED WITHIN THE ITCZ. A WEAK RIDGE COVERS THE E/CENTRAL ATLC N OF 20N E OF 60W WITH A WEAKNESS IN THE IMMEDIATE VICINITY OF THE SURFACE TROUGH. $$ WALLACE