000 AXPZ20 KNHC 071019 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0915 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM LOW PRES NEAR 05N78W 1009 MB TO 09N81W TO 07N86W TO 05N102 WHERE IT TRANSITIONS TO ITCZ AND EXTENDS TO LOW PRES NEAR 09N118W 1010 MB TO 07N129W TO 09N140W. SCATTERED MODERATE ISOLATED STRONG 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 126W. ...DISCUSSION... A STRONG BLOCKING UPPER PATTERN PERSISTS ACROSS THE BROADER REGION BETWEEN 80W AND 160W THIS MORNING....WITH A SERIES OF COMPLEX TROUGHS GENERALLY W OF 120W...AND A BROAD UPPER RIDGE CENTERED ACROSS THE NW U.S. A HIGH AMPLITUDE TROUGH EXTENDS SOMEWHAT N TO S ALONG 149W/150W...WITH STRONG SWLY FLOW ROUNDING THE BASE OF THIS TROUGH AND EXTENDING IN A BROAD ZONE NE ACROSS MUCH OF THE DISCUSSION AREA N OF 10N W OF 110W. AN EMBEDDED SHORTWAVE TROUGH WAS ALONG 123W/124W BETWEEN 20N AND 30N. SHORTWAVE RIDGING TO THE SW OF THIS WAS PROVIDING A FAVORABLE ENVIRONMENT FOR SCATTERED DEEP CONVECTION N OF THE ITCZ W OF 126W AS MENTIONED ABOVE. TO THE SE...A DOWNSTREAM RIDGE IS ANCHORED ON AN UPPER ANTICYCLONE JUST OFF THE W COAST OF GUATEMALA EXTENDING NE ACROSS THE NW CARIBBEAN AND INTO THE WRN N ATLC WELL BEYOND 30N75W. DRY AND STABLE ATMOSPHERIC CONDITIONS PREVAIL UNDER THE RIDGE E OF 105W...EXCEPT WHERE A WEAK TUTT AXIS HAS DEVELOPED OVER THE MONSOON TROUGH 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 OVER THE CENTRAL PLAINS OF THE UNITED STATES 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. A SHARP INCREASE IN GAP FLOW HAS BEGUN HERE OVERNIGHT... WITH WINDS EXPECTED TO QUICKLY REACH GALE FORCE AROUND SUNRISE THIS MORNING AND THEN PEAK AT 40-45 KT THIS EVENING. DOWNSTREAM SEAS ARE EXPECTED TO REACH A MAXIMUM OF NEAR 18 FT WED NIGHT BEFORE SLOWLY SUBSIDING TO 10-12 FT THU AFTERNOON. GULF OF CALIFORNIA...HIGH RESOLUTION SCATTEROMETER WINDS FROM AN 0438 UTC PASS CONTINUE TO REVEAL 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...A PERSISTENT 1010 MB LOW PRES SYSTEM CENTERED NEAR 09N118W IS MOVING WESTWARD AT 10 KT. STRONG SW UPPER SHEAR HAS TOTALLY DISSIPATED THE PREVIOUS LARGE CLUSTERS OF STRONG CONVECTION NOTED TO THE N AND E OF THE LOW. THE LOW WILL CONTINUE ON A WESTWARD TRACK AND CONTINUE TO WEAKEN DURING THE NEXT DAY AND LIKELY DISSIPATE TO AN OPEN TROUGH BY 48 HRS. THE PRES GRADIENT BETWEEN THE LOW AND HIGH PRES RIDGING TO ITS N WILL ALLOW FOR WINDS 0F 20-25 KT IN THE 240 NM NW QUADRANT...AND S OF THE ASSOCIATED RIDGE TO THE ITCZ...WHERE NE TO E TRADES OF 20-25 KT PREVAIL 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. $$ STRIPLING