000 AXPZ20 KNHC 271607 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC SUN NOV 27 2011 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 1500 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH CROSSES CENTRAL AMERICA NEAR 09N83W TO 06N92W TO 09N102W TO 08N106W THEN TRANSITIONS TO ITCZ TO 10N118W TO LOW PRES NEAR 09N122W TO 08N127W TO 09N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 90 NM N OF AXIS BETWEEN 112W AND 122W. SCATTERED MODERATE CONVECTION NOTED WITHIN 60 NM OF AXIS BETWEEN 126W AND 133W. ...DISCUSSION... A TROUGH/RIDGE/TROUGH PATTERN DOMINATES THE REGION N OF 10N FROM 160W TO 100W. A LONG WAVE UPPER TROUGH CONTINUES TO PROGRESS SLOWLY E ACROSS CENTRAL N AMERICA WITH A MEAN MIDDLE/UPPER LEVEL AXIS EXTENDING FROM CENTRAL TEXAS SW ACROSS NRN MEXICO TO A MID LEVEL CYCLONE NEAR 20N110W...WITH TROUGH CONTINUING SW TO 16N119W. AN ANTICYCLONIC CIRCULATION CENTERED NEAR 10N136W EXTENDS A RIDGE NE BEYOND 32N123W. W OF THE RIDGE...ANOTHER LONG WAVE UPPER TROUGH IS APPROACHING THE FAR NW CORNER OF THE FORECAST AREA. THE ASSOCIATED COLD FRONT IS SLOWING ACROSS THE NW CORNER OF THE REGION AND EXTENDS FROM 30N138W TO 28N140W. NLY WINDS OF 20-25 KT ARE EXPECTED W OF THE FRONT AS WELL AS LONG PERIOD NW SWELL WITH BUILDING SEAS TODAY OF 12 TO 16 FT. THE FRONT IS FORECAST TO STALL THEN MOVE W OF 140W IN ABOUT 24 HOURS AS HIGH PRES STRENGTHENS N OF FORECAST REGION AND THE SUPPORTING SHARP UPPER TROUGH PINCHES OFF AN UPPER VORTEX ALONG 28N. THE PRES GRADIENT BETWEEN HIGH PRES AND THE WWD DRIFTING FRONT WILL PRODUCE AN AREA OF E TO SE WINDS OF 20 TO 25 KT MAINLY N OF 20N W OF 135W IN ABOUT 48 HOURS. THE REMNANTS OF KENNETH ARE STILL NOTED ON SATELLITE IMAGERY AS A WELL DEFINED SWIRL OF LOW TO MIDDLE CLOUDS WITH A SCATTERED SHOWERS AND ISOLATED TSTMS SPINNING NEAR 14N139W. THIS FEATURE IS ANALYZED AS A SURFACE TROUGH ALONG 139W ON THE 1200 UTC SURFACE MAP. THE PRES GRADIENT BETWEEN A 1027 MB HIGH CENTERED NEAR 32N128W AND THE ITCZ IS PRODUCING AN AREA OF FRESH NE TO E TRADEWINDS FROM 12N TO 18N W OF 118W...WITH SEAS OF 9 TO 11 FT IN MIXED NE AND NW SWELL. GULF OF CALIFORNIA...THE MID LEVEL VORTEX OF THE GULF OF CALIFORNIA HAS INDUCED A WEAK SURFACE TROUGH ALONG THE MEXICAN COAST S OF 21N AND HAS COMBINED WITH THE SURFACE HIGH MENTIONED ABOVE TO PRODUCE A SHIFT IN WINDS THROUGH THE GULF TO NELY THIS MORNING...STILL ABOUT 20 TO 25 KT ACROSS MOST OF THE GULF. SEAS HAD BUILT TO 8 FT IN NNW WIND SWELL OVERNIGHT AND ARE NOT MIXING WITH DEVELOPING NE WIND WAVES TO MAKE FOR ROUGH AND CONFUSED SEAS 6 TO 7 FT...ESPECIALLY ALONG THE E COASTAL WATERS OF THE BAJA PENINSULA. WINDS ARE EXPECTED TO SHIFT MORE ELY ACROSS THE S HALF OF THE GULF IN THE NEXT 12 HOURS AND DIMINISH TO 15 TO 20 KT THEN RETURN TO MORE NNW THROUGH THE ENTIRE BASIN TONIGHT.THE E PACIFIC HIGH IS EXPECTED TO LIFT N OF THE AREA LATE MONDAY AND WEAKEN THE PRES GRADIENT ACROSS THE AREA...DROPPING WINDS BELOW 20 KT BY MONDAY AFTERNOON. ATTENTION REMAINS FOCUSED ON THE NEXT GULF OF TEHUANTEPEC WIND EVENT...FORECAST TO BE THE FIRST STORM FORCE WIND EVENT OF THE SEASON. NLY WINDS OF 20 TO 30 KT HAVE BEGUN TO BLOW THROUGH THE GULF OF TEHUANTEPEC TO ABOUT 13N LATE THIS MORNING...AND WILL QUICKLY INCREASE TO GALE FORCE BY EARLY THIS AFTERNOON (1800 UTC). COMPUTER MODEL GUIDANCE IS IN GENERAL AGREEMENT THAT WINDS WILL FURTHER INCREASE TO STORM FORCE (50 KT) BY THIS EVENING OR EARLY TONIGHT. SEAS ARE EXPECTED TO BUILD IN EXCESS OF 15-20 FT IN ASSOCIATION WITH THESE STORM FORCE WINDS TONIGHT. A STORM WARNING REMAINS IN EFFECT FOR THIS AREA. THIS GAP WIND EVENT IS FORECAST TO PEAK THIS EVENING THROUGH MON MORNING THEN DIMINISH TO GALE FORCE EARLY MON AFTERNOON AND CONTINUE THROUGH TUE MORNING. GALE CONDITIONS SHOULD END LATE TUE MORNING BUT STRONG N WINDS MAY PERSIST THROUGH THE MIDDLE OF NEXT WEEK. THIS GAP WIND EVENT WILL BE ASSOCIATED WITH A STRONG COLD SURGE BEHIND A COLD FRONT CURRENTLY MOVING SE ACROSS THE GULF OF MEXICO. WHEN COLD AIR OUTBREAKS OCCUR OVER THE GULF OF MEXICO... THE SIERRA MADRE MOUNTAINS BLOCK THE LARGE SCALE FLOW OF COLD AIR SOUTHWARD RESULTING IN THE DEVELOPMENT OF A STRONG NORTH-SOUTH PRES GRADIENT ACROSS THE ISTHMUS OF TEHUANTEPEC. NLY FLOW IS THEN FUNNELED THROUGH THE CHIVELA PASS INTO THE GULF OF TEHUANTEPEC. THIS GAP FLOW OFTEN RESULTS IN A NARROW JET OF WIND THAT CAN REACH GALE...STORM AND OCCASIONALLY HURRICANE FORCE. $$ STRIPLING