000 AXPZ20 KNHC 052159 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC WED DEC 05 2012 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2115 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM CENTRAL COLOMBIA W TO THE GULF OF PANAMA...TO SRN COSTA RICA...THEN TURNS SW TO 08N92W WHERE LOW LEVEL WINDS INDICATE IT TRANSITIONS TO THE ITCZ WHICH CONTINUES TO 9N101W TO 08N110W TO 07N121W TO 07N130W TO 06N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 180 NM S OF THE ITCZ BETWEEN 101W-112W. SCATTERED MODERATE CONVECTION EXISTS FROM 07N-10N BETWEEN 112W-119W. BROKEN-LOCALLY OVERCAST LOW-MID LEVEL CLOUDS WITH ISOLATED SHOWERS IS NOTED ELSEWHERE WITHIN 120 NM OF THE MONSOON TROUGH AND ITCZ AXIS. ...DISCUSSION... ALOFT...A NEARLY STATIONARY UPPER CYCLONE IS CENTERED AT 19N.5N127W WITH A TROUGH STRETCHING SSE TO 13N125W TO 08N123W TO NEAR 07N119W. BROAD RIDGING COVERS THE AREA SE OF THE UPPER CYCLONE TO ACROSS CENTRAL AMERICA AND NRN S AMERICA. A DEEP LAYERED CYCLONE IS OVER LOUISIANA WITH AN UPPER TROUGH EXTENDING SW TO A BASE OVER OLD MEXICO AT 20N105W. THIS PATTERN SETS UP AN AREA OF UPPER DIFFLUENCE THAT IS IN PHASE WITH THE ITCZ BETWEEN 100-120W...AND IS ENHANCING THE CONVECTION DESCRIBED ABOVE. THE RESULTANT DENSE UPPER DEBRIS MOISTURE...IN THE FORM OF BROKEN TO SCATTERED CIRRUS CLOUDS...IS BEING ADVECTED N FROM THE ITCZ BETWEEN 118W-125W...TURNING E ACROSS THE UPPER RIDGE NEAR 22N118W...THEN CONCENTRATING INTO A NARROW MOISTURE PLUME THAT CONTINUES E ALONG THE BASE OF THE UPPER TROUGH ACROSS CENTRAL OLD MEXICO...AND THE SOUTHERN GULF OF MEXICO. OUTSIDE THE PLUME OF UPPER LEVEL MOISTURE...WATER VAPOR IMAGERY SHOWS MODERATE TO STRONG SUBSIDENCE MAINTAINING DRY AND STABLE CONDITIONS NOTED BY THE PATCHES OF BROKEN TO OVERCAST STRATOCUMULUS CLOUDS WITH ISOLATED SHOWERS N OF 10N W OF ABOUT 117W. THE UPPER TROUGH OVER CENTRAL MEXICO WILL SHIFT EWD OVER THE NEXT 24 HRS...WITH LITTLE OVERALL CHANGES EXPECTED ELSEWHERE. AT THE SURFACE TO LOW LEVELS...A 1024 MB SURFACE HIGH IS ANALYZED AT 29N131.5W WITH A RIDGE EXTENDING SE TO NEAR 19N110W AND ANOTHER RIDGE SW TO W OF THE AREA AT 26N140W. THE ASCAT PASS FROM 1532 UTC THIS MORNING SHOWED RATHER LIGHT S-SW WINDS NW OF THE RIDGE W OF 135W....WITH COMBINED SEAS 7-8 FT IN MIXING SW WIND WAVE AND LONG PERIOD NW SWELL. THE TRADES SW OF THE WESTERN RIDGE ARE AT 20-25 KT IN THE AREA FROM 06-21N W OF 123W WITH SEAS 8-10 FT IN MIXED SHORT PERIOD NE AND LONG PERIOD NW SWELL. CROSS EQUATORIAL SE-S LONG PERIOD SWELL IS MIXING WITH LONG PERIOD NW SWELL RESULTING IN COMBINED SEAS 7-8 FT IN THE TROPICAL WATERS S OF 05N BETWEEN 105-110W. THE SURFACE HIGH IS FORECAST TO MOVE SW WHILE WEAKENING THROUGH THU WITH A RIDGE SE TO NEAR 18N107W. A WEAK COLD FRONT WILL ENTER AND STALL OVER THE FAR NW WATERS ON THU BUT ONLY ACCOMPANIED BY A 5-10 KT SW TO NW WIND SHIFT. A SECOND COLD FRONT WILL STALL JUST NW OF THE AREA LATE FRI. THE AREA OF ENHANCED TRADES SW OF THE RIDGE WILL DIMINISH TO 07-21N W OF 125W ON THU...AND FROM 07-21N W OF 132W ON FRI AS THE NE TRADES DIMINISH TO 15-20 KT AND SEAS SUBSIDE TO 6-9 FT IN THE NE SWELL. THE GRADIENT WILL TIGHTEN NE OF THE SURFACE RIDGE...GENERALLY TO THE N OF 28N BETWEEN 117-127W...ON THU NIGHT AS A LARGE AND STRONG AREA OF HIGH PRES BUILDS S INTO FRI. THE GRADIENT WILL SUPPORT NW 15-20 KT AND SEAS 7-9 FT IN NW SWELL. EXPECT NW WINDS AT 10-15 KT WITH SEAS 3-6 FT ALONG THE W COAST OF THE BAJA CALIFORNIA PENINSULA THROUGH THE UPCOMING WEEKEND. GAP WINDS... GULF OF TEHUANTEPEC...N-NE WINDS AT 20-30 KT ARE SURGING THROUGH THE CHIVELA PASS AND IN AND DOWNSTREAM OF THE GULF OF TEHUANTEPEC. THESE WINDS WILL BE RATHER SHORT-LIVED AS MODEL GUIDANCE FORECASTS THEM TO DIMINISH TO 20-25 KT LATE IN THE MORNING ON FRI AND TO 20 KT OR LESS BY THU EVENING. GULF OF PAPAGAYO...NE WINDS WILL CONTINUE TO PULSE AT 10-15 KT IN AND DOWNSTREAM OF THE GULF OF PAPAGAYO THROUGH MON THEN INCREASE TO 15-20 KT LATE TUE. $$ AGUIRRE