000 AXPZ20 KNHC 200346 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC MON DEC 20 2010 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0300 UTC. TROPICAL LOWS... LOW PRES 1011 MB NEAR 08N116W HAS SCATTERED MODERATE CONVECTION WITHIN 240 NM E QUADRANT OF CENTER. FRESH SW WINDS WITHIN 120 NM SE QUADRANT WITH SEAS STILL BELOW 8 FT. LOW PRES MOVE W AT 15 KT WITH LITTLE CHANGE THROUGH 24 HRS THEN WEAKEN AND DISSIPATE WITHIN 48 HRS. SECOND WEAK STATIONARY LOW PRES 1009 MB AT 07N85W MAINTAINS FRESH SW WIND IN SE QUADRANT. LOW PRES DRIFTS W AFTER 24 HRS BUT REMAINS WEAK THROUGHOUT PERIOD. DIMINISHING SCATTERED MODERATE CONVECTION REMAINS IN S SEMICIRCLE THROUGH 48 HRS. ITCZ... AXIS FROM LOW PRES AT 08N83W TO 04N90W TO 11N112W TO 05N1140W. NO SIGNIFICANT CONVECTION. DISCUSSION... BROAD ANTICYCLONIC FLOW COVERS LARGE PART OF BASIN ALOFT WITH MODERATE TO STRONG SUBSIDENCE KEEPING MOISTURE REDUCED TO SMALL POCKETS IN VICINITY OF LOW LEVEL FEATURES MENTIONED ABOVE. ONLY ADDITIONAL MOISTURE NOTED ENTERED E PAC WITH UPPER LEVEL TROUGH THAT SUPPORTS WEAK COLD FRONT PRESENTLY FROM 32N127W TO 25N140W. DEEPER STRONGER UPPER LEVEL TROUGH ENTERS BASIN WITHIN 24 HRS REINFORCING LOW LEVEL COLD AIR ADVECTION AND INCREASING LOW LEVEL WINDS TO STRONG OR NEAR GALE THROUGH 48 HRS. ELSEWHERE AT THE SURFACE... COLD FRONT BRINGS FRESH SW WINDS N OF 27N WITHIN 240 NM AHEAD OF FRONT AND LARGE LONG PERIOD SWELLS BEHIND. REINFORCING CAA INCREASES WINDS TO STRONG BY END OF FORECAST PERIOD AND BUILDS SEAS TO 12 FT...MAINLY IN NW PART OF BASIN. WEAK HIGH PRES CENTER 1016 MB AT 24N123W HAS RIDGE EXTEND TO 16N110W WITH MODERATE NE BREEZE N SEMICIRCLE OF LOW PRES AT 08N116W. GAP WINDS... IN GULF OF PAPAGAYO...LATE NIGHT DRAINAGE FLOW COMBINED WITH WEAK LOW PRES 1009MB TO THE S LIKELY TO PROMOTE STRONGER FLOW OVER SMALL OFFSHORE AREA PROMPTING FRESH NE WINDS WITHIN 06 HRS AND LASTING THROUGH REMAINDER OF PERIOD OR UNTIL LOW DRIFTS AWAY FROM AREA. LOW PRES ALSO PRODUCING FRESH SW WIND FLOW OVER ITS SE QUADRANT THROUGH PERIOD. $$ WALLY BARNES