000 AXPZ20 KNHC 230950 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC THU DEC 23 2010 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0945 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 03N77W TO AN EMBEDDED LOW PRES CENTER AT 07N101W...THEN THE AXIS CONTINUES W TO 10N131W TO 08N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS WITHIN 90 NM EITHER SIDE OF A LINE FROM 08N96W TO 07N105W AND ALSO WITHIN 15 NM OF 10N133W. THE EMBEDDED LOW CENTER IS EXPECTED TO CONTINUE DRIFTING W AND GRADUALLY LOSING IDENTITY IN THE ITCZ. A TROUGH IS ORIENTATED N TO S FROM 09N133W TO 14N131W. THIS TROUGH IS EXPECTED TO DRIFT W AND GRADUALLY LOSE IDENTITY OVER THE NEXT 48 HOURS. OTHERWISE...THERE IS NO SIGNIFICANT CONVECTION ALONG THE ITCZ. ...DISCUSSION... A LONG WAVE TROUGH OVER THE WESTERN CONUS EXTENDS SSW INTO THE DISCUSSION AREA N OF 13N ALONG 125W. A SHORT WAVE TROUGH IS MOVING SE INTO THE LONG WAVE WITH AN DEEP LAYERED CYCLONE OVER SOUTHERN CALIFORNIA TRAILING A SURFACE COLD FRONT FROM THE NORTHERN GULF OF CALIFORNIA TO NEAR 22N128W. SURFACE WINDS HAVE DIMINISHED ALONG THE FRONT BUT HAVE INCREASED IN THE TRADE WIND BELT FROM 10N TO 14N W OF 130W. SEAS W OF THE FRONT ARE IN 9 TO 13 FT RANGE...BUT ARE EXPECTED TO SUBSIDE TO ABOUT 10 FT BEFORE REACHING THE NORTHERN BAJA CALIFORNIA PENINSULA LATER TODAY. SOUTHERLY SURFACE WINDS ARE ARE ABOUT 20 KT AHEAD THE FRONT OVER THE NORTHERN GULF OF CALIFORNIA WATERS BUT SHOULD DIMINISH TO LESS THAN 20 KT EARLY TODAY. A SURFACE HIGH WILL BUILD W OF THE FRONT BUT SHIFT NE OF THE AREA TONIGHT AS THE NEXT COLD FRONT MOVES INTO THE NW PORTION AT 30N140W BY SUNRISE FRI. AN UPPER ANTICYCLONE IS ESTIMATED NEAR 13N110W WITH AN UPPER RIDGE EXTENDING NNE THROUGH 32N91W AND ACROSS THE SE CONUS. DRY UPPER AIR ASSOCIATED WITH THE SHORT WAVE OVER THE PACIFIC HAS FURTHER ERODED THE PERSISTENT TROPICAL MOISTURE PLUME TO ONLY 150 NM WIDE THIS MORNING...WITH ITS AXIS ALONG 18N140W TO 16N120W TO BEYOND 32N102W...WITH THIS TRAJECTORY OVER THE AGRICULTURE AREAS OF NW OLD MEXICO. SCATTERED MODERATE ISOLATED STRONG CONVECTION HAS DEVELOPED WITHIN 90 NM OF 18N119W WITH THE DEBRIS MOISTURE MERGING INTO THE THE TROPICAL PLUME JUST DESCRIBED. ANOTHER DENSE MOISTURE PLUME IS SPREADING E ACROSS THE PACIFIC N OF 30N W OF 120W. LOOKS LIKE SOME OF THIS MOISTURE WILL WRAP AROUND THE CALIFORNIA CYCLONE LATER TODAY...WITH THE DENSE MOISTURE ESTIMATED TO ARRIVE OVER THE SW CONUS COAST ON FRI. UPPER MOISTURE FROM THE CONVECTION NEAR 07N101W IS ADVECTED NE BUT SEEMS TO EVAPORATE BEFORE REACHING THE COAST OF CENTRAL AMERICA. SCATTERED MODERATE ISOLATED STRONG CONVECTION HAS DEVELOPED WITHIN 90 NM OF 18N119W. CROSS EQUATORIAL SE WINDS AT 15 TO 20 KT ARE NOTED OVER THE TROPICAL WATERS S OF 07N W OF 118W WITH THE AFFECTED AREA EXPECTED TO DECREASE TO W OF 125W IN 48 HOURS. GAP WINDS...LATE NIGHT DRAINAGE FLOW WILL RESULT IN NNE 20 KT WINDS IN THE GULF OF TEHUANTEPEC AROUND SUNRISE THIS MORNING INCREASING TO 20 TO 25 KT LATER TODAY BEFORE DIMINISHING TO LESS THAN 20 KT ON FRI. NE WINDS ARE EXPECTED TO CONTINUE TO PULSE AT 15 TO 20 KT IN AND JUST DOWNSTREAM OF THE GULF OF PAPAGAYO THROUGH FRI MORNING...THEN DIMINISH. N WINDS AT 15 TO 20 KT IN AND DOWNSTREAM OF THE GULF OF PANAMA SHOULD DIMINISH THIS AFTERNOON. $$ NELSON