000 AXPZ20 KNHC 192202 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SUN DEC 19 2010 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 2100 UTC. TROPICAL LOWS... WELL DEFINED LOW PRES 1010 MB NEAR 09N115W HAS SCATTERED CONVECTION WITHIN 300NM SE 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 AT 08N85W MAINTAINS FRESH SW WIND IN SE QUADRANT. LOW PRES DRIFTS W AFTER 24 HRS BUT REMAINS WEAK THROUGHOUT PERIOD. SCATTERED MODERATE CONVECTION REMAINS IN S SEMICIRCLE THROUGH 48 HRS. ITCZ... AXIS FROM LOW PRES AT 08N85W TO 04N91W TO 11N113W TO 05N35W 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 LOW LEVEL FEATURES MENTIONED ABOVE. ONLY MOISTURE NOTED JUST ENTERED E PAC WITH UPPER LEVEL TROUGH THAT SUPPORTS WEAK COLD FRONT PRESENTLY FROM 32N124W TO 26N140W. DEEPER STRONGER UPPER LEVEL TROUGH ENTERS BASIN WITHIN 24 HRS REINFORCING COLD AIR ADVECTION INCREASING LOW LEVEL WINDS SIGNIFICANTLY THROUGH 48 HRS. ELSEWHERE AT THE SURFACE... COLD FRONT BRINGS FRESH SW WINDS WITHIN 300 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. GAP WINDS... COLD FRONT OVER GULF OF MEXICO PREVIOUSLY SUPPORTING GULF OF TEHUANTEPEC EVENT HAS MOVED SE AND WINDS VEERED SE EFFECTIVELY CUTTING OFF NLY FLOW ACROSS ISTHMUS. IN THE GULF OF PAPAGAYO...LATE NIGHT DRAINAGE FLOW COMBINED WITH WEAK LOW PRES 1010 MB TO THE S ARE LIKELY TO PROMOTE STRONGER FLOW OVER SMALL AREA OFFSHORE RESULTING IN FRESH NE WINDS WITHIN 12 HRS AND LASTING THROUGH REMAINDER OF PERIOD OR UNTIL LOW DRIFTS AWAY FROM AREA. LOW PRES ALSO PROMPTING FRESH SW WIND FLOW OVER ITS SE QUADRANT THROUGH PERIOD. $$ WALLY BARNES