000 AXPZ20 KNHC 071532 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC WED DEC 07 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 1530 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM LOW PRES NEAR 06N78W 1009 MB TO 09N85W TO 05N100W TO 05N108W WHERE IT TRANSITIONS TO ITCZ AND EXTENDS TO TROUGH ALONG 07N121W 12N117W TO 08N140W. SCATTERED MODERATE CONVECTION NOTED WITHIN 90 NM S OF TROUGH BETWEEN 86W AND 96W. SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 180 NM N OF ITCZ W OF 130W. ...DISCUSSION... A STRONG BLOCKING UPPER PATTERN PERSISTS ACROSS THE BROADER REGION BETWEEN 80W AND 160W....WITH A SERIES OF COMPLEX TROUGHS GENERALLY W OF 120W...AND A BROAD UPPER RIDGE CENTERED ACROSS THE NW U.S. A FAIRLY HIGH AMPLITUDE TROUGH EXTENDING SSW FROM 32N147W TO JUST SE OF THE BIG ISLAND OF HAWAII NEAR 15N155W. STRONG AND DIFFLUENT SWLY MID TO UPPER LEVEL FLOW ROUNDING THE BASE OF THIS TROUGH COVERS A BROAD ZONE OF THE DISCUSSION AREA GENERALLY FROM 06N TO 27N W OF 127W. THIS AREA OF DIFFLUENT FLOW WAS PROVIDING A FAVORABLE ENVIRONMENT FOR SCATTERED DEEP CONVECTION WITHIN 180 NM N OF THE ITCZ W OF 126W AS MENTIONED ABOVE. TO THE SE...A DOWNSTREAM RIDGE IS ANCHORED ON AN UPPER ANTICYCLONE JUST S OF THE GULF OF TEHUANTEPEC EXTENDING NE ACROSS THE NW CARIBBEAN AND INTO THE WRN N ATLC WELL BEYOND 32N73W. DRY AND STABLE ATMOSPHERIC CONDITIONS PREVAIL UNDER THE RIDGE E OF 105W...EXCEPT WHERE A WEAK TUTT AXIS HAS DEVELOPED OVER THE MONSOON TROUGH BETWEEN 87W AND 95W AND WAS AIDING IN PROVIDING MID LEVEL LIFT FOR ACTIVE CONVECTION THERE. THE OVERALL BROAD SCALE PATTERN WILL CHANGE LITTLE OVER THE DISCUSSION AREA THROUGH THE NEXT 24-48 HRS AS THIS REX-TYPE BLOCKING PATTERN CONTINUES N OF THE REGION...ALLOWING FOR BROAD RIDGING TO PREVAIL WITH NO FRONTS EXPECTED TO CROSS S OF 32N. GULF OF TEHUANTEPEC...HIGH PRES BUILDING SWD ALONG THE SIERRA MADRE OF MEXICO HAS INCREASED THE PRES GRADIENT BETWEEN THE NORTHERN COAST OF THE ISTHMUS OF TEHUANTEPEC AND ITS SOUTHERN TERMINUS BEHIND A STALLED COLD FRONT OVER THE SW GULF OF MEXICO. THE GAP FLOW HAS REACHED GALE FORCE WITH A SHIP OF CALL SIGN ELWR5 REPORTING 35 KT WINDS AT 1200 UTC WHILE LOCATED NEAR 14.5N 95.2W. THE GALE EVENT IS FORECAST TO PEAK THIS EVENING WITH 40-45 KT WINDS EXPECTED IN THE AREA. DOWNSTREAM SEAS ARE EXPECTED TO REACH A MAXIMUM OF NEAR 16-17 FT TONIGHT BEFORE SLOWLY SUBSIDING TO 10-12 FT LATE THU. GULF OF CALIFORNIA...AN EARLIER HIGH RESOLUTION SCATTEROMETER WINDS FROM AN 0438 UTC PASS REVEALED NW-N WINDS OF 20-25 KT SWEEPING THROUGH THE SRN GULF TO AS FAR S AS 22N E OF 109W. NE-E WINDS ALSO CONTINUE TO BE FORCED ACROSS AND THROUGH PASSES IN THE BAJA CALIFORNIA PENINSULA AND INTO THE OPEN PACIFIC WATERS TO THE W OF THE PENINSULA...BUT HAVE BEGUN TO DIMINISH FROM THE PAST 24 HOURS. AS THE GRADIENT SLACKENS OVER THE NEXT 24-48 HRS...WINDS WILL RESPOND BY DIMINISHING TO 20 KT AND LESS BY THU MORNING AFTER SUNRISE. FURTHER SW...THE 1010 MB LOW PRES SYSTEM CENTERED EARLIER NEAR 09N118W HAS DEGENERATED INTO A SURFACE TROUGH WHICH EXTENDS FROM 07N121W TO 12N117W. THIS FEATURE CONTINUES MOVING WESTWARD AT 10 KT. THE COMBINATION OF STRONG SW UPPER SHEAR AND DEEP LAYERED SUBSIDENCE HAS TOTALLY DISSIPATED THE PREVIOUS LARGE CLUSTERS OF STRONG CONVECTION NOTED WITH THE TROUGH/FORMER LOW. THE TROUGH WILL CONTINUE ON A WESTWARD TRACK AND WILL LIKELY DISSIPATE ALTOGETHER BY 48 HRS. THE PRES GRADIENT BETWEEN THE TROUGH AND HIGH PRES RIDGING TO ITS N WILL ALLOW FOR WINDS OF 20-25 KT OVER AN AREA FROM 13N TO 20N W OF 133W AND FROM 12N TO 20N BETWEEN 126W AND 133W WITH SEAS OF 8-10 FT THROUGH 24 HRS. GULF OF PAPAGAYO...NE 20 KT WINDS WILL CONTINUE TO PULSE UP AND DOWN DOWNWIND OF THE GULF OF PAPAGAYO THROUGH THE NEXT 48 HOURS IN THE LATE NIGHT AND EARLY MORNING HOURS DURING PEAK DRAINAGE FLOW OFF CENTRAL AMERICA. THESE OCCURRENCES SHOULD NOT LAST LONG ENOUGH TO BE INCLUDED IN THE HIGH SEAS FORECAST. $$ COBB