000 AXNT20 KNHC 231100 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT FRI OCT 23 2009 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 1015 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS TILTED FROM 10N38W TO 20N35W AND DRIFTING NW. THE WAVE IS EMBEDDED WITHIN A MAXIMUM AREA OF DEEP LAYER MOISTURE AS DEPICTED BY TOTAL PRECIPITABLE WATER IMAGERY N OF 10N BETWEEN 27W-35W. CIMSS WAVETRAK MODEL GUIDANCE ALSO INDICATES A NARROW AREA OF 850 MB RELATIVE VORTICITY IN THE VICINITY OF THE WAVE AXIS N OF 10N BETWEEN 33W-39W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS OCCURRING FROM 12N-21N BETWEEN 26W-37W PRIMARILY EAST OF THE WAVE AXIS. THIS ACTIVITY IS BEING ENHANCED BY AN AREA OF UPPER LEVEL DIFFLUENCE LOCATED E OF AN UPPER LEVEL SHORTWAVE TROUGH WITH AXIS DIPPING SOUTH TO 15N ALONG 35W. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 9N13W 7N23W 7N32W 6N57W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 2N-10N BETWEEN 20W-38W. ...DISCUSSION... GULF OF MEXICO... AS OF 0900 UTC...A COLD FRONT ENTERS THE GULF NEAR BILOXI MISSISSIPPI AND EXTENDS SW ALONG 25N92W INTO EASTERN MEXICO NEAR TAMPICO TURNING STATIONARY ALONG THE EASTERN SLOPES OF THE SIERRA MADRE ORIENTAL MOUNTAINS. A PRE-FRONTAL SURFACE TROUGH EXTENDS FROM 23N94W TO 20N96W. LOW-LEVEL CONVERGENCE NEAR BOTH OF THESE SURFACE BOUNDARIES IS GENERATING SCATTERED SHOWERS AND TSTMS WITHIN 120 NM OF A LINE FROM 22N95W TO INLAND OVER SOUTHERN ALABAMA NEAR MOBILE BAY. THE FRONT IS SUPPORTED ALOFT BY A BROAD UPPER LEVEL TROUGH ACROSS THE CENTRAL CONUS WITH THE UPPER LOW CENTERED OVER WESTERN IOWA THIS MORNING. A DRY AND STABLE AIRMASS FOLLOWS BEHIND THE FRONT WITH NW WINDS UP TO 25 KT. AN UPPER LEVEL RIDGE ANCHORED OVER THE EASTERN BAY OF CAMPECHE NEAR 19N92W EXTENDS A RIDGE AXIS NE OVER THE NE GULF AND FLORIDA PENINSULA THUS ENHANCING THE CONVECTION ASSOCIATED WITH THE COLD FRONT. CARIBBEAN SEA... A 1007 MB LOW REMAINS QUASI-STATIONARY IN THE SW CARIBBEAN OFF THE COAST OF NICARAGUA NEAR 13N83W. MOSTLY SCATTERED SHOWERS ACCOMPANY THIS LOW ACROSS THE SW CARIBBEAN S OF 15N W OF 80W AS MOST CONVECTION IS BEING INHIBITED BY HIGH SHEAR VALUES ASSOCIATED WITH THE BASE OF A HIGHLY AMPLIFIED UPPER LEVEL TROUGH THAT EXTENDS FROM THE SW NORTH ATLC TO AN UPPER LOW CENTERED OVER EASTERN CUBA AND CONTINUES S-SW TO NICARAGUA. THE TROUGH IS LOCATED BETWEEN A BROAD UPPER LEVEL RIDGE OVER THE GULF OF MEXICO AND NW CARIBBEAN AND A SECOND UPPER LEVEL RIDGE ANCHORED OVER VENEZUELA THAT EXTENDS A RIDGE AXIS ACROSS THE EASTERN CARIBBEAN ALONG 68W. THIS UPPER LEVEL PATTERN IS PROVIDING THE NW AND FAR EASTERN CARIBBEAN WITH STRONG SUBSIDENCE AND A DRY AIRMASS IN PLACE WITH ONLY A FEW ISOLATED SHOWERS OBSERVED ON SATELLITE IMAGERY MOVING ACROSS THE LEEWARD ISLANDS AND PUERTO RICO. A SWATH OF MOISTURE IS ACROSS THE FAR SW AND CENTRAL CARIBBEAN WITH SCATTERED SHOWERS FROM 10N-20N BETWEEN 71W-77W. AN AREA OF SCATTERED STRONG TSTMS ARE OCCURRING NORTH OF PANAMA FROM 10N-13N BETWEEN 78W-81W. ATLANTIC OCEAN... A NARROW AMPLIFIED UPPER LEVEL TROUGH AXIS EXTENDS SW FROM 30N70W THROUGH THE CENTRAL BAHAMAS TO AN UPPER LOW CENTERED OVER EASTERN CUBA AND DIPPING S INTO THE WESTERN CARIBBEAN SEA. THIS UPPER LEVEL TROUGH IS PROVIDING STRONG SUBSIDENCE AND DRY STABLE AIR W OF 77W AND ALSO SUPPORTS A SURFACE TROUGH ANALYZED FROM 25N73W TO 20N75W. A 1009 MB SURFACE LOW HAS DEVELOPED OVER THE PAST 6 HOURS AND IS LOCATED ALONG THE SURFACE TROUGH NEAR 22N75W. LOW-LEVEL CONVERGENCE NEAR THE SURFACE TROUGH COUPLED WITH UPPER LEVEL DIFFLUENCE E OF THE UPPER LEVEL TROUGH AXIS IS GENERATING SCATTERED SHOWERS FROM 20N-27N BETWEEN 65W-76W. A BROAD UPPER LEVEL TROUGH IS OVER THE CENTRAL ATLC N OF 28N AND SUPPORTS A COLD FRONT N OF THE REGION TO NEAR 31N39W. LINGERING WEAK LOW-LEVEL CONVERGENCE TRAILS TO THE WEST ALONG 26N BETWEEN 50W-65W AND CONTINUES TO PRODUCE ISOLATED LOW-LEVEL SHOWERS FROM 24N-27N BETWEEN 52W-65W. EAST OF THE COLD FRONT ACROSS THE CENTRAL ATLC...A PRE-FRONTAL SURFACE TROUGH IS ANALYZED FROM 23N47W TO BEYOND 32N34W WITH SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING WITHIN 200 NM E OF THE SURFACE TROUGH. ACROSS THE EASTERN ATLC...A SURFACE RIDGE IS PRESENT ANCHORED BY A 1021 MB HIGH CENTERED NW OF THE MADEIRA ISLANDS NEAR 34N14W. IN THE TROPICAL ATLC...A 1010 MB LOW IS N OF THE ITCZ AXIS CENTERED NEAR 14N44W WITH ISOLATED SHOWERS WITHIN A 200 NM RADIUS OF THE LOW CENTER. $$ HUFFMAN