000 AXNT20 KNHC 220543 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT THU OCT 22 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 32W S OF 18N MOVING W NEAR 10 KT. THE WAVE COINCIDES WITH A MAXIMUM IN TOTAL PRECIPITABLE WATER AS WELL AS AN AREA OF MAXIMUM 850 MB RELATIVE VORTICITY IN GLOBAL MODEL FIELDS IN THE VICINITY OF THE WAVE AXIS. CYCLONIC CURVATURE OF THE LOW LEVEL CLOUD FIELD IS NOTED ON SATELLITE IMAGERY WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 13N-18N BETWEEN 25W-31W. THE CONVECTION IS CONTINUING TO BE ENHANCED BY AN UPPER RIDGE OVER THE TROPICAL EASTERN ATLC. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 11N15W 10N29W 10N34W 10N62W. CLUSTERS OF SCATTERED SHOWERS AND ISOLATED MODERATE CONVECTION ARE FROM 3N-9N BETWEEN 18W-35W. ...DISCUSSION... GULF OF MEXICO... THE GULF IS DOMINATED BY A SURFACE RIDGE ANCHORED IN THE W ATLC LOCATED EAST OF THE NORTH CAROLINA COAST. SELY RETURN FLOW ASSOCIATED WITH THE SURFACE RIDGE AND THE RESULTING INCREASED PRESSURE GRADIENT CONTINUES TO IMPACT THE GULF WITH WINDS UP TO 25 KT ACROSS MUCH OF THE GULF. LOW-LEVEL CONVERGENCE AHEAD OF THE NEXT COLD FRONT CURRENTLY POSITIONED ACROSS WESTERN TEXAS IS GENERATING ISOLATED SHOWERS OVER THE NORTHERN GULF WATERS N OF 25N W OF 88W. SIMILAR ACTIVITY IS MOVING WESTWARD OVER THE SE GULF AND PORTIONS OF THE FLORIDA PENINSULA. AN AMPLIFIED UPPER LEVEL RIDGE EXTENDS FROM SOUTHERN MEXICO OVER THE BAY OF CAMPECHE TO THE SE CONUS. THIS UPPER RIDGE IS ENHANCING MUCH OF THE CURRENT SHOWERS AND TSTM ACTIVITY OBSERVED INLAND OVER TEXAS THIS EVENING. AS THE SURFACE RIDGE SLIDES EASTWARD...THE NEXT COLD FRONT IS FORECAST TO ENTER THE NW GULF WATERS LATE THURSDAY. CARIBBEAN SEA... A 1007 MB LOW IS IN THE SW CARIBBEAN OFF THE COAST OF NICARAGUA NEAR 12N83W. SCATTERER SHOWERS AND ISOLATED TSTMS ARE OCCURRING OVER THE SW CARIBBEAN AND PORTIONS OF CENTRAL AMERICA FROM 9N-16N BETWEEN 76W-87W. THIS AREA IS UNDER THE INFLUENCE OF THE BASE OF AN UPPER TROUGH THAT DIPS SOUTHWARD FROM CUBA TO EASTERN HONDURAS. UPPER LEVEL DIFFLUENCE E OF THE TROUGH AXIS IS ENHANCING THE CONVECTION ASSOCIATED WITH THE SURFACE LOW. FARTHER EAST...AN UPPER LEVEL RIDGE IS ANCHORED OVER NW VENEZUELA WITH RIDGE AXIS ALONG 70W WHILE UPPER LEVEL TROUGHING COVERS THE REMAINDER OF THE EASTERN CARIBBEAN E OF 65W PROVIDING A DRY STABLE AIRMASS AND GIVING GENERALLY CLEAR SKIES. A FEW ISOLATED LOW-LEVEL SHOWERS HOWEVER ARE PRIMARILY N OF 16N AND E OF 68W. ATLANTIC OCEAN... A BROAD UPPER LEVEL TROUGH COVERS THE WESTERN AND CENTRAL ATLC N OF 30N WITH A NARROW AMPLIFIED TROUGH AXIS EXTENDING S OVER THE SW NORTH ATLC THROUGH 30N75W ACROSS CUBA INTO THE NW CARIBBEAN SEA. THIS AMPLIFIED UPPER LEVEL TROUGH IS PROVIDING STRONG SUBSIDENCE AND MOSTLY DRY STABLE AIR W OF 76W WITH ONLY A FEW ISOLATED SHOWERS MOVING WESTWARD OVER THE NW BAHAMAS AND FLORIDA PENINSULA. THE BROAD UPPER LEVEL TROUGH IS SUPPORTING A DISSIPATING COLD FRONT THAT ENTERS THE CENTRAL ATLC NEAR 32N49W EXTENDING SW TO 28N56W. WEST OF THE COLD FRONT...A SURFACE RIDGE ANCHORED BY A 1024 MB HIGH OFF THE COAST OF NORTH CAROLINA CONTINUES TO PROVIDE NE TO ELY FLOW W OF 56W. AN UPPER LEVEL RIDGE EXTENDS FROM NEAR 20N65W TO 28N60W PROVIDING DIFFLUENCE ALOFT TO GENERATE AN AREA OF SCATTERED SHOWERS AND ISOLATED TSTMS S OF 28N TO OVER HISPANIOLA AND EASTERN CUBA BETWEEN 67W-76W. A SURFACE TROUGH EXTENDS FROM 28N48W TO 22N60W. LOW-LEVEL CONVERGENCE LOCATED TO THE EAST OF THE SURFACE TROUGH ALONG WITH A MID-LEVEL SHORTWAVE TROUGH WITH AXIS ALONG 45W N OF 20N IS SUPPORTING SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 120 NM OF A LINE FROM 21N45W TO BEYOND 32N39W. A WEAK SURFACE RIDGE DOMINATES THE REMAINDER OF THE EASTERN ATLC ANCHORED BY A 1018 MB HIGH CENTERED NEAR 29N26W. IN THE TROPICAL ATLC...A 1010 MB LOW IS N OF THE ITCZ NEAR 14N42W WITH SCATTERED SHOWERS AND ISOLATED TSTMS E OF THE LOW FROM 12N-16N BETWEEN 37W-42W. $$ HUFFMAN