000 AXPZ20 KNHC 090343 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SUN DEC 09 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0315 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS W FROM LOW PRES OVER NW COLOMBIA ACROSS THE PANAMA/COSTA RICA BORDER TO 09N85W...THEN TURNS SW THROUGH AN EMBEDDED 1008 MB LOW PRES AT 08N95W AND TO 07N100W WHERE LOW LEVEL WINDS INDICATE A TRANSITION TO AN ITCZ AXIS THAT EXTENDS TO 11N106W TO 10N120W TO 08N130W 07N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM S OF THE ITCZ AXIS W OF 134W. ...DISCUSSION... ALOFT...A PERSISTENT LONGWAVE UPPER RIDGE IS W OF THE AREA WITH ITS MEAN AXIS NEAR 149W/150W WHILE A LONGWAVE TROUGH OVER CENTRAL U.S. EXTENDS SW TO NEAR 29N126W. SATELLITE WATER VAPOR IMAGERY SHOWS A SHORTWAVE TROUGH SWINGING SEWD THROUGH THE BASE OF THE LONGWAVE TROUGH FROM 32N123W TO 27N131W AND INTO A MID/UPPER CYCLONE MOVING SLOWLY S AT 26N140W WHICH OCCASIONALLY INDUCES A SURFACE TROUGH OVER THE FAR NW WATERS. ANOTHER SHORTWAVE TROUGH EXTENDS FROM 32N112W SW TO 18N120W...THEN TURNS SEWD TO 14N118W TO 09N110W TO NEAR 02N106W. BETWEEN THIS TROUGH AND THE MID/UPPER CYCLONE...A SHORTWAVE RIDGE SLIDING EWD IS JUST S OF FIRST SHORTWAVE TROUGH ROUGHLY ALONG 27N123W 16N123W. DENSE UPPER MOISTURE...IN THE FORM OF BROKEN CIRRUS CLOUDS...IS NOTED UNDER THIS RIDGE...WITHIN 200 NM EITHER SIDE OF THE RIDGE. THESE CLOUDS SPREAD AS FAR NE AS 28N121W WHERE SW-W FLOW S OF THE FIRST SHORTWAVE TROUGH STEERS THEM TOWARDS NRN BAJA CALIFORNIA AND OVER FAR NW MEXICO. TO THE SE OF THE SHORTWAVE TROUGH POSITIONED ALONG 32N112W 18N120W...BROAD MID/UPPER LEVEL RIDGING COVERS THE AREA WITH A MEAN AXIS EXTENDING NW TO SE FROM 26N115W TO 18N104W. THIS PATTERN SETS UP AN AREA OF UPPER DIFFLUENCE SUPPORTING ENHANCED BROKEN TO OVERCAST MULTILAYERED CLOUDS WITH SCATTERED SHOWERS AND ISOLATED TSTMS FROM 11N TO 26N E OF 116W. THE RESULTANT DEBRIS MOISTURE CONTINUES TO BE ADVECTED NNE ALONG THE W PERIPHERY OF THE UPPER RIDGE...WITHIN 240 NM OF A LINE FROM 11N114W TO 26N114W. THIS MOISTURE PLUME THEN TURNS E-NE ACROSS THE UPPER RIDGE AXIS...THINNING SOMEWHAT AS IT CONTINUES NEWD TO THE S AND SE OF THE LONGWAVE TROUGH AXIS...AND WELL E OF THE AREA TO OVER MUCH OF THE GULF OF MEXICO AND THE SE CONUS. WATER VAPOR IMAGERY CONTINUES TO SHOW VERY DRY AND STABLE ATMOSPHERIC CONDITIONS OVER THE SE PART OF THE AREA WITHIN THE MID/UPPER LEVEL RIDGING. THESE DRY AND STABLE CONDITIONS ARE SUPPRESSING CONVECTION EXCEPT ISOLATED SHOWERS WITHIN 60-75 NM OF THE MONSOON TROUGH LOW AT 08N95W. AT THE LOW LEVELS...A 1029 MB HIGH CENTER N OF THE AREA AT 39N134W EXTENDS A RIDGE SEWD THROUGH 32N130W TO NEAR 22N115W. NLY WINDS OF 15-20 KT ARE NOTED TO THE NE OF THE RIDGE...N OF ABOUT 27N BETWEEN 120W AND 131W...WITH SEAS 8-10 FT IN MIXED NE AND NW SWELL. THESE WINDS ARE EXPECTED TO CHANGE LITTLE OVER THE NEXT 48 HRS. THE TRADES SW OF THE RIDGE ARE AT 15-20 KT IN THE AREA FROM 08-22N W OF 127W...WITH SEAS 7-9 FT PRIMARILY IN MIXING NE AND NW SWELL. THE GRADIENT IS EXPECTED TO TIGHTEN ON SUN WITH NE 15-20 KT WINDS COVERING THE WATERS NW OF LINE FROM 32N120W TO 11N140W WITH SEAS 7-9 FT MAINLY IN A NE SWELL. BY LATE MON INTO TUE NE WINDS OF 15-20 KT ARE FORECAST TO THE N OF 11N AND W OF 131W...WITH SEAS OF 7-9 FT IN A N TO NE SWELL. EXPECT NW WINDS AT 5-10 KT WITH SEAS 3-5 FT ALONG THE W COAST OF THE BAJA CALIFORNIA THROUGH SUN MORNING. A COLD FRONT IS FORECAST TO SWEEP S INTO THE EXTREME NE WATERS...INCLUDING THE GULF OF CALIFORNIA ON SUN AFTERNOON. THIS WILL RESULT IN WINDS BECOMING NE 15-20 KT ALONG THE W COAST OF THE BAJA PENINSULA LATE SUN NIGHT INTO MON. WINDS BEHIND THE FRONT ARE TO BECOME NW AT 20-25 KT IN THE NRN WATERS OF THE GULF OF CALIFORNIA...AND BRIEFLY INCREASE TO 25-30 KT LATE SUN NIGHT INTO MON PER THE GFS 10M WIND GUIDANCE. NW WINDS OF 15-25 KT ARE FORECAST TO SPREAD S ACROSS THE ENTIRE GULF BY MON NIGHT. EXPECT SEAS MAY BUILD TO AROUND 8 FT BRIEFLY IN THE NRN GULF WATERS MON IN THE AREAS OF LONG NW FETCH...AND 4-6 FT SOUTHERN GULF WATERS BY LATE MON NIGHT. THESE NW WINDS SHOULD DIMINISH TO 10-15 KT TUE NIGHT. GAP WINDS... GULF OF TEHUANTEPEC...A COLD FRONT WILL ENTER THE NW GULF OF MEXICO SUN NIGHT. THE ASSOCIATED NLY WINDS WILL SURGE AT 15-20 KT THROUGH THE CHIVELA PASS TUE AFTERNOON...WITH WINDS GRADUALLY INCREASING TUE NIGHT AND EARLY WED...REACHING NEAR GALE FORCE BY LATE WED...AND CONTINUING INTO MIDDAY THU. NOTE THAT LATEST MODEL GUIDANCE IS NOT AS AGGRESSIVE AS PREVIOUS RUNS. GULF OF PAPAGAYO... BOTH ASCAT AND OSCAT DATA FROM SAT MORNING AND AFTERNOON RESPECTIVELY HIGHLIGHTED NE WINDS OF 15-20 KT WITHIN 90 NM NW OF THE GULF OF PAPAGAYO. EXPECT THESE WINDS TO CONTINUE INTO SUN...THEN DIMINISH TO 10-15 KT SUN AFTERNOON WITH LITTLE CHANGE INTO WED. ON WED NIGHT...MODEL GUIDANCE (GFS BEING THE MOST PRONOUNCED) SUGGESTS THAT NE WINDS WILL BEGIN TO PULSE DOWNSTREAM OF THE GULF AT THE INCREASED SPEEDS OF 20-25 KT WHILE SPREADING WSW INTO THE FORECAST WATERS. $$ AGUIRRE