000 AXPZ20 KNHC 192205 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC FRI DEC 19 2008 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 6N77W 67N90W 5N100W 10N113W 10N122W 8N131W 6N1140W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM S OF THE AXIS BETWEEN 115W-120W. THIS CONVECTION IS EXPECTED TO REMAIN ACTIVE THROUGH THE NEXT 12-18 HOURS. ...DISCUSSION... AN OMEGA BLOCKING PATTERN MAITIANIS CONTROL OF THE EASTERN PACIFIC DEFINED BY AN UPPER LEVEL LONGWAVE TROUGH THAT EXTENDS FROM THE NORTHERN GREAT PLAINS SW ACROSS SOUTHERN CALIFORNIA TO INTO THE AREA AT 32N124W...THEN CONTINUES SW TO A WELL PRONOUNCED CUT-OFF UPPER LOW MOVING S 20 KT NEAR 24N132W. THE TROUGH EXTENDS SE TO 15N130W TO 12N121W. A WEAK MID/UPPEL LEVEL CYCLONIC CYLONIC CIRCULATION CENTER IS ALONG THE TROUGH NEAR 12N125W. JET STREAM ENERGY DIVING OVER A HIGH AMPLITUDE LARGE RIDGE W OF THE AREA AND INTO THE BACK SIDE OF THE LONGWAVE TROUGH WILL AID IN THE INTENSIFICATION AND FURTHER SWD MOVEMENT OF THE UPPER LOW NEAR 24N132W DURING THE NEXT 48 HOURS. THE CYCLONIC CIRCULATION IS FORECAST TO RETROGRADE WSW DURING THE NEXT SEVERAL DAYS. A WEAKENING SURFACE TROUGH...REFLECTION OF THE UPPER LEVEL LOW...IS MOVING S 15 KT FROM 23N130W TO 20N137W. STRONG S TO SW FLOW ALOFT GENERALLY BETWEEN 111W AND 121W STREAMING FROM THE ITCZ NE TOWARDS BAJA CALIFORNIA...NORTHERN MEXICO AND THE SW UNITED STATES CONTINUES TO SUPPORT A FAVORABLE UPPER LEVEL ENVIRONMENT ENHANCING CONVECTION WITHIN THIS AREA WHERE CIMSS TPW LOOPS SHOW AMPLE MOISTURE CONVERGING DUE TO STRONG AND PERSISTENT EASTERLY FLOW IN THE TROPICAL ZONE. CONVECTION IS LIKELY TO PERSIST DURING THE NEXT 12-18 HOURS WITH THE ADDITIONAL AID OF A WESTWARD MOVING SURFACE TROUGH ALONG 121W FROM 8N-16N. GLOBAL MODEL GUIDANCE SUGGESTS THAT THIS TROUGH FEATURE OR EVEN A WEAK SURFACE LOW WILL MOVE WNW OVER THIS AREA DURING THE NEXT 48 HOURS WITH ATTENDANT MOISTURE AREA AND CONVECTION TRANSLATING WESTWARD WITH THE TROUGH. THE PRES GRADIENT BETWEEN SURFACE HIGH PRES CENTERED NEAR 32N124W AND THE SURFACE TROUGH ALONG 121W CONTINUES TO MAINTAIN A BROAD SWATH OF 20 TO 25 KT NE WINDS...N AND W OF THE LOW LEVEL TROUGH AND THE ITCZ...FROM 28N120W TO BEYOND 14N140W. WITHIN THIS SWATH OF FRESH NE WINDS SEAS ARE RUNNING 8 TO 10 FT AND WILL INCREASE TO 10 TO 12 FT BETWEEN 16N AND 21N DURING THE NEXT 36 HOURS. THE SURFACE HIGH IS ALSO USHERING NORTHERLY WINDS OF 20 TO 25 KT ALONG THE W COAST OF BAJA CALIFORNIA S TO 25N...WITH INCREASING WINDS AND SEAS EXPECTED TODAY THROUGH THE LENGTH OF THE GULF OF CALIFORNIA...TO AROUND 20 KT AND 6 FT. ACTIVE CONVECTION IS EXPECTED TO CONTINUE ACROSS A BROAD AREA BETWEEN THE ITCZ AND 22N AND BETWEEN 132W AND 110W AS THE DIGGING UPPER LOW INTERACTS FAVORABLY WITH ABUNDANT MOISTURE IN THE VICINITY OF THE LOW LEVEL INVERTED TROUGH ALONG 117W. S TO SW WINDS ALOFT ACROSS THIS CONVECTIVELY ACTIVE AREA WILL CONTINUE TO TRANSPORT UPPER LEVEL MOISTURE AND CONVECTIVE DEBRIS ACROSS THE BAJA AND THE NORTH HALF OF MEXICO DURING THE NEXT SEVERAL DAYS. A NEARLY STATIONARY FRONT PASSES THROUGH 26N109W TO 22N112W TO 19N122W TO 16N128W. SCATTERED MODERATE SHOWERS AND ISOLATED THUNDERSTORMS WERE OCCURRING WITHIN 90 NM OF THIS BOUNDARY...MAINLY ACROSS THE CENTRAL GULF OF CALIFORNIA. GAP WINDS... N-NE WINDS OF 20-25 KT THROUGH THE GULF OF TEHUANTEPEC AND PAPAGAYO ARE EXPECTED TO DIMINISH TO LESS THAN 20 KT BY 48 HOURS WHILE N WINDS OF AROUND 20 KT THROUGH THE GULF OF PANAMA WILL DIMINISH TO LESS THAN 20 KT BY 24 HOURS. $$ AGUIRRE