000 AXPZ20 KNHC 160346 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC FRI JAN 16 2009 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 0330 UTC. ...ITCZ... ITCZ IS CENTERED ALONG 5N77W 7N86W 6N97W 7N110W 6N120W 7N130W 6N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION EXISTS FROM 8N-15N BETWEEN 118W-127W. SCATTERED MODERATE CONVECTION IS WITHIN 30 NM N OF THE AXIS BETWEEN 82W-85W...AND WITHIN 60 NM S OF THE AXIS BETWEEN 128W-130W. ...DISCUSSION... THE REGION REMAINS IN BETWEEN TWO RATHER LARGE SCALE FEATURES. THE FIRST IS THE TAIL END OF BROAD UPPER LEVEL TROUGHING CENTERED OVER THE MID-WEST REGION OF THE UNITED STATES WHICH REACHES INTO THE FAR EASTERN SECTION OF THE AREA TO N OF ABOUT 27N AND E OF 125W. W OF THE TROUGH...THE AREA IS UNDER MID AND UPPER LEVEL RIDGING PRESENT N OF 24N WITH AN ASSOCIATED ANTICYCLONIC CENTER WELL N OF THE AREA. THE SECOND FEATURE CONTINUES TO BE A RATHER EXTENSIVE LATITUDINAL DEEP LAYER TROUGH STRETCHING ROUGHLY ALONG 135W N OF 18N...THEN SE TO A SMALL MID/UPPER LEVEL CYCLONIC CIRCULATION NEAR 13N131W. A MID/UPPER LEVEL LOW MOVING E IS ON THE FAR SOUTHERN PERIMETER OF THE TROUGH AXIS NEAR 12N134W. THE ASSOCIATED SURFACE COLD FRONT IS W OF THE AREA...HOWEVER SLY WINDS OF 20 KT PRECEDE THE FRONT... AND ARE NOW BEING REPORTED BY SEVERAL SHIPS OVER THE FAR NW WATERS OF THE AREA. DATA INFERRED FROM SATELLITE-DERIVED WINDS SHOWS QUITE A LARGE AREA OF UPPER LEVEL DIVERGENCE CONTINUING TO ENHANCE SCATTERED MODERATE TO ISOLATED STRONG CONVECTION CLUSTERS TO THE E OF THE BASE OF THE TROUGH ALONG AND N OF THE ITCZ AXIS GENERALLY CONFINED FROM 8N TO 15N BETWEEN 120W AND 129W. EXPECT THIS ACTIVITY TO CONTINUE OVER THE NEXT FEW DAYS AS THE TROUGH GRADUALLY TRANSLATES MAINLY IN A N TO NE DIRECTION. SOME OF THE GLOBAL MODELS SUGGEST THAT AN EVENTUAL WEAK LOW MAY EVOLVE FROM THIS AREA AND DRIFT NWD OVER THE NEXT 48 HOURS. MODERATE TO STRONG UPPER LEVEL WINDS ARE ALONG AND W OF THE TROUGH AXIS N OF 26N. THESE WINDS CONTINUE TO TRANSPORT UPPER LEVEL MOISTURE IN THE FORM OF HIGH LEVEL CLOUDS N TO WELL N OF THE REGION. THE SURFACE COLD FRONT IS FORECAST TO SLOW ITS FORWARD MOTION AND WEAKEN JUST NW OR IN THE EXTREME FAR NW CORNER OF THE AREA OVER THE THE NEXT 3 DAYS AS ITS DRIVING UPPER SUPPORT AND RELATED ENERGY PULLS FURTHER AWAY FROM THE AREA TOWARDS THE GENERAL VICINITY OF ALASKA AS GLOBAL MODELS ARE IN PRETTY CLOSE AGREEMENT WITH RESPECT TO THIS SCENARIO. HOWEVER...THE MAIN ISSUE WITH THIS FRONT AND THE VERY PROGRESSIVE UPPER LATITUDE FRONTAL SYSTEMS THAT FOLLOW BEHIND IT WILL BE LONG PERIOD NW SWELLS GENERATED BY ATTENDANT DEEP LOW PRES SYSTEMS THAT WILL ALSO PASS WELL TO THE N OF 30N OVER THE NEXT FEW DAYS. WAVEWATCH MODEL GUIDANCE IS VERY CONSISTENT IN SHOWING SIGNIFICANT WAVE HEIGHTS OF UP TO 13 FT NOW ENTERING THE FAR NW CORNER OF THE AREA. THESE SEAS WILL POSSIBLY GROW UP TO 1 FT BY FRI NIGHT WITH SEAS ELSEWHERE RANGING 9-14 FT W OF 130W. WILL HAVE TO MONITOR THIS UPCOMING SWELL EVENT CLOSELY WITH RESPECT TO PROJECTED FORECAST HEIGHTS AND AREAL COVERAGE AS PORTRAYED IN FUTURE MODEL GUIDANCE. ELSEWHERE...BROAD SW TO W UPPER LEVEL COVERS THE AREA SW OF THE BROAD UPPER LEVEL TROUGH OVER THE EASTERN PART OF THE AREA... AND TO THE E OF THE DEEP LAYERED TROUGH OVER TH FARE WESTERN PORTION OF THE AREA. THIS FLOW PATTERN BECOMES CONFLUENT OVER THE FAR EASTERN PART OF THE AREA E OF SOUTHERN BAJA CALIFORNIA TO OVER NORTHERN MEXICO WHERE A JET STREAM BRANCH WITH MAXIMUM WINDS OF UP TO 65 KT ROUNDS THE BASE OF THE THIS TROUGH. POSSIBLE HIGH LEVEL TURBULENCE IN TRANSVERSE BANDING OF CIRRUS CLOUDS IS NOTED FROM 10N TO 20N E OF THE 117W. THE CONFLUENT FLOW ASSOCIATED WITH THE BROAD UPPER LEVEL TROUGH IS RESULTING IN MODERATE TO STRONG SUBSIDENCE INDUCING DRY STABLE AIR OVER MUCH OF THE AREA N OF 24N E OF THE DEEP LAYER TROUGH DESCRIBED IN FIRST PARAGRAPH. BROAD UPPER LEVEL ANTICYCLONIC FLOW COVERS THE AREA S OF 20N AND TO THE W OF THE TROUGH ALONG 21N119W TO 17N113W TO 8N105W. AT THE SURFACE...HIGH PRES RIDGING SWD OVER THE WESTERN GULF OF MEXICO AND MEXICO MAINTAINS A TIGHT PRES GRADIENT ALONG THE MEXICAN COAST USHERING GALE FORCE WINDS IN THE RANGE OF 30-35 KT INTO THE GULF OF TEHUANTEPEC EARLY THIS EVENING. THESE WINDS ARE FORECAST TO INCREASE TO JUST UNDER STORM STRENGTH OVER THE NEXT 24 TO 36 HOURS AS INDICATED BY THE LATEST 10M AND 30M MODEL WIND GUIDANCE. THIS SCENARIO WILL BE HIGHLY DEPENDENT ON WHETHER GULF SSTS WILL BE WARM ENOUGH FOR DOWNWARD MOMENTUM OF COLD AIR OVER TO ALLOW FOR SUFFICIENT MIXING OVER THESE WATERS TO ALLOW FOR STORM FORCE WINDS TO DEVELOP AT THAT TIME. PRESENTLY...IT APPEARS THAT THE VERY STRONG ANTICYCLONE OVER THE MID-WEST REGION OF THE U.S. WILL SHIFT ESE AND WEAKEN OVER THE NEXT 48 HOURS ALLOWING FOR TIGHT PRES GRADIENT CURRENTLY ALONG AND JUST INLAND THE MEXICAN COAST TO WEAKEN AND NOT CONTRIBUTE TO ANY FURTHER INTENSIFICATION OF GAP WINDS. NE WINDS OF 20 KT THROUGH THE GULF OF PAPAGAYO ARE EXPECTED TO INCREASE TO 25 KT IN ABOUT 12 HOURS AS STRONG HIGH PRES RIDGING PRESSES SWD OVER CENTRAL AMERICA AND STRONG SW CARIBBEAN TRADES ADVECT WESTWARD ACROSS CENTRAL AMERICA. THESE WINDS MAY ARE EXPECTED TO CHANGE LITTLE OVER THE NEXT 48 HOURS. ELSEWHERE HIGH PRES COVERS THE AREA N OF ABOUT 13N W OF 110W WITH A RIDGE FROM 30N131W TO SW OF THE AREA AT 22N140W. $$ AGUIRRE