000 AXPZ20 KNHC 141605 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC FRI DEC 14 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1545 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...THE MONSOON TROUGH EXTENDS FROM NW COLOMBIA SW TO 08N78W TO 08N85W TO 07N95W WHERE LOW LEVEL WINDS INDICATE IT TRANSITIONS TO AN ITCZ THAT EXTENDS TO 07N105W TO 06N117W TO 09N130W TO BEYOND 10N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM S OF THE TROUGH BETWEEN 78W-80W...WITHIN 60 NM OF THE TROUGH BETWEEN 121W-126W AND ALSO WITHIN 30 NM OF THE TROUGH BETWEEN 90W-95W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF THE TROUGH BETWEEN 129W-131W. ...DISCUSSION... ...A VERY FAST AND HIGHLY AMPLIFIED UPPER LEVEL FLOW PATTERN OVER THE AREA... A LONGWAVE TROUGH OVER THE WRN U.S. EXTENDS TO AN UPPER LEVEL LOW OVER WRN NEVADA. THE TROUGH CONTINUES SW FROM THE LOW TO NEAR 26N127W TO W OF THE REGION AT 23N140W. THE ASSOCIATED 997 MB SURFACE LOW OVER WRN NEVADA HAS AN ASSOCIATED SURFACE COLD FRONT THAT EXTENDS SEWD TO NW MEXICO...AND THEN SW TO ACROSS SRN BAJA CALIFORNIA AND TO NEAR 21N120W. A RATHER POTENT SHORTWAVE TROUGH IS WELL DEPICTED ON SATELLITE WATER VAPOR IMAGERY TO BE QUICKLY MOVING SEWD FROM 32N131W NEWD TO ALONG THE PACIFIC U.S. NW COAST. A SURFACE LOW OF 1005 MB ASSOCIATED WITH THIS FEATURE IS FAR N OF THE AREA AT 40N126W WITH A COLD FRONT SW TO NEAR 35N134W. SUBTLE MID/UPPER LEVEL RIDGING BETWEEN THIS TROUGH AND THE UPPER CYCLONE OVER WRN NEVADA WILL SLIDE EWD THROUGH TONIGHT AS THE SHORTWAVE TROUGH SWEEPS SEWD ACROSS NRN BAJA CALIFORNIA. THE FIRST COLD FRONT WILL MOVE E OF THE AREA AND DISSIPATE LATE TONIGHT...WHILE THE SURFACE LOW PRES SYSTEM ASSOCIATED WITH THE SHORTWAVE TROUGH WILL MOVE SE TO NEAR 32N119W TONIGHT WITH A COLD FRONT SW TO 27N126W. THIS LOW WILL QUICKLY LIFT NEWD THROUGH SAT MORNING WITH THE COLD FRONT SW TO 27N119W. NW 20-25 KT W OF THE FIRST COLD FRONT WILL BE REPLACED BY A SIMILAR WIND CONDITIONS FORECAST TO FOLLOW IN BEHIND THE SECOND COLD FRONT. SEAS ARE EXPECTED TO BE IN THE RANGE OF 8-10 FT BEHIND THE FIRST COLD FRONT...BUT BUILD SOME BEHIND THE SECOND FRONT TONIGHT AND EARLY SAT TO POSSIBLY NEAR 12 FT. A STRONG PRES GRADIENT AHEAD OF BOTH FRONTS WILL MAINTAIN S-SW WINDS OF 20-25 KT ACROSS THE FAR NRN PORTION OF THE GULF OF CALIFORNIA THROUGH SAT MORNING. THESE WINDS THEN DIMINISH SW 10-15 KT DURING SAT AFTERNOON ONCE THE SECOND COLD FRONT MOVES E OF THE FORECAST PACIFIC WATERS AND DISSIPATES INLAND. SATELLITE WATER VAPOR IMAGERY SHOWS A VERY LARGE DEEP LAYER ANTICYCLONE COVERING THE FAR NW WATERS...AND EXTENDING TO WELL NW AND W OF THE DISCUSSION AREA. NLY UPPER FLOW AROUND ITS NRN PERIPHERY IS ADVECTING EXTENSIVE MOISTURE IN THE UPPER LEVELS OF THE ATMOSPHERE NOTED AS BROKEN TO OVERCAST CIRRUS CLOUDS. THE THINNER STRANDS OF THESE CLOUDS HAVE REACHED THE EXTREME FAR NW CORNER OF THE AREA. MODERATE SUBSIDENCE IS NOTED WITHIN 200 NM OF THE LONGWAVE TROUGH DESCRIBED ABOVE WITH RESULTANT DRY AND STABLE ATMOSPHERIC CONDITIONS SEEN AS COLD AIR STRATOCUMULUS CLOUDS ADVECTING SWD BEHIND THE SURFACE COLD FRONT THAT EXTENDS FROM SRN BAJA CALIFORNIA SW TO NEAR 21N120W. SIMILAR WEATHER CONDITIONS ARE NOTED N OF 20N AND W OF THIS SAME FRONT. THE SURFACE REFLECTION OF THE DEEP LAYER ANTICYCLONE IS ANALYZED AS A RIDGE THAT STRETCHES FROM A 1032 MB WELL NW OF THE AREA AT 33N153W SE THROUGH 29N140W AND TO NEAR 23N125W. THE PRES GRADIENT BETWEEN THE RIDGE AND LOWER PRES IN THE TROPICS IS MAINTAINING AN AREA OF NE 20-25 KT TRADES FROM 10N TO 23N W OF 130W WITH SEAS TO 9 FT. THE 1032 MB HIGH CENTER IS FORECAST TO CHANGE VERY LITTLE THROUGH THE NEXT 48 HRS WITH THE RIDGE EXPANDING SOME TO THE E. THE NE 20-25 KT TRADES ARE FORECAST TO INCREASE EWD IN AREAL COVERAGE TO NEAR 120W BY EARLY ON SUN...WITH SEAS BUILDING TO AROUND 12 FT W OF 135W. A SUBTROPICAL JETSTREAM BRANCH ROUNDS THE BASE OF THE LONGWAVE TROUGH ENTERING THE AREA THROUGH 23N140W. IT EXTENDS NE TO 22N128W TO 24N120W AND FARTHER NEWD TO ACROSS CENTRAL BAJA CALIFORNIA AND TO WELL THE SW U.S. AND FARTHER NE TO THE CENTRAL MID-WED REGION OF THE U.S. MAXIMUM JET STREAM WINDS ARE IN THE RANGE OF 80-120 KT FROM 15N TO 20N W OF 122W. THIS JET STREAM SEPARATES CYCLONIC FLOW TIED TO THE LONGWAVE TROUGH WITH ANTICYCLONIC FLOW TO ITS S RELATED TO A BROAD ANTICYCLONIC FLOW ACROSS THE SRN HALF OF THE AREA WITH A MEAN CENTER SW OF THE AREA AT 06N152W. RIPPLES OF UPPER LEVEL ENERGY FLOWING WITH THE JET STREAM ARE TRANSPORTING AMPLE MOISTURE IN THE UPPER LEVELS OF THE ATMOSPHERE E AND NE ACROSS THE DISCUSSION AREA. THIS MOISTURE IS OBSERVED AS OVERCAST MAINLY MID AND UPPER LEVEL CLOUDINESS WITH EMBEDDED PATCHES OF LIGHT RAIN...WIDELY SCATTERED SHOWERS AND POSSIBLE SHORT-LIVED TSTM CELLS. THIS PATTERN IS FORECAST TO PERSIST THROUGH THE NEXT 48 HRS. A WEAK SURFACE TROUGH IS ALONG 116W FROM 09N TO 11N MOVING W AT 15-20 KT. IT IS UNDER A WEAK SHORTWAVE TROUGH THAT IS EMBEDDED WITHIN THE JET STREAM. ONLY ISOLATED TSTMS ARE WITHIN 30 NM OF THIS SURFACE TROUGH. GAP WINDS... GULF OF TEHUANTEPEC...N-NE WINDS OF 20-25 KT WITHIN 45 NM EITHER SIDE OF A LINE FROM 16N94.5W TO 15N95W TO 14N96W AND THROUGH THE GULF ARE EXPECTED TO DIMINISH BY EARLY TONIGHT AS THE GRADIENT OVER SE MEXICO SLACKENS. THE NEXT GAP WIND EVENT IS EXPECTED TO BEGIN LATE TUE NIGHT...PEAKING AT 25 KT. $$ AGUIRRE