000 AXPZ20 KNHC 081011 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC THU DEC 08 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 1010 MB TO 09.5N84W TO 05N94W WHERE IT TRANSITIONS TO ITCZ AND EXTENDS TO 09N121W TO 07N135W TO 07N140W. SCATTERED MODERATE CONVECTION NOTED WITHIN 120 NM S OF TROUGH BETWEEN 87W AND 90W. SCATTERED MODERATE ISOLATED STRONG WITHIN 210 NM N OF THE ITCZ W OF 122W. ...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 FLAT UPPER RIDGE CENTERED ACROSS THE CENTRAL U.S. A FAIRLY HIGH AMPLITUDE TROUGH EXTENDS SSW FROM 37N141W TO JUST SE OF THE BIG ISLAND OF HAWAII NEAR 14N154W. 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 210 NM N OF THE ITCZ W OF 122W AND ALSO FROM 12N TO 21N W OF 131. TO THE SE...A DOWNSTREAM TROPICAL RIDGE IS ANCHORED ON AN UPPER ANTICYCLONE NEAR 12N116W EXTENDING N TO ABOUT 32N AND E TO NEAR 12N92W. DRY AND STABLE ATMOSPHERIC CONDITIONS PREVAIL ACROSS SE PORTIONS OF THE RIDGE E OF 115W...EXCEPT WHERE A WEAK TUTT AXIS HAS DEVELOPED OVER THE MONSOON TROUGH ACROSS THE FAR TROPICAL EPAC. THE OVERALL BROAD SCALE PATTERN WILL CHANGE ONLY MODESTLY ACROSS THE DISCUSSION AREA THROUGH THE NEXT 24-48 HRS AS LOW BROAD LATITUDE RIDGING PREVAILS...CENTERED ON A PERSISTENT HIGH NEAR 14N116W AND EXTENDING N TO 30N. THIS PATTERN WILL CONTINUE TO FORCE SHORTWAVE ENERGY OVER THE RIDGE AND REMAIN OUTSIDE OF THE AREA...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 REACHED GALE FORCE YESTERDAY AND CONTINUES THIS MORNING TO 40 KT PER A RECENT 0008 UTC WINDSAT PASS. THIS GALE EVENT IS FORECAST TO BEGIN TO DIMINISH THIS MORNING AND FALL BELOW GALE FORCE LATE THIS AFTERNOON. DOWNSTREAM SEAS HAVE REACHED A MAXIMUM OF AROUND 16 FT OVERNIGHT AND SHOULD SLOWLY SUBSIDE TO 8-10 FT THROUGH FRI. GULF OF CALIFORNIA...THE PRES GRADIENT IS SLOWLY DECREASING ACROSS THIS AREA...AND WINDS HAVE BEGUN TO WEAKEN ACROSS THE BASIN...WITH A PARTIAL 0421 UTC ASCAT PASS SHOWING 20-25 KT WINDS FUNNELING THROUGH AND DOWNSTREAM OF THE ANGEL DE LA GUARDIA AND TIBURON ISLANDS...LIKELY CONTINUING TO THE MOUTH NEAR 22N. THE PRES GRADIENT WILL CONTINUE TO SLACKEN OVER THE NEXT 24 HRS...WINDS WILL RESPOND BY DIMINISHING TO 20 KT AND LESS BY LATE THIS MORNING. FURTHER SW...A LOW LEVEL TROUGH WAS ESTIMATED ALONG 139W/140W FROM 12N TO 22N...MOVING WESTWARD. THE PRES GRADIENT BETWEEN THE TROUGH AND HIGH PRES RIDGING TO ITS N WILL MAINTAIN NE TO E WINDS OF 20-25 KT OVER AN AREA FROM FROM 08N TO 16N BETWEEN 120W AND 136W AND FROM 16N TO 21N W OF 132W WITH SEAS OF 8-11 FT THROUGH THE NEXT 24 HRS...AND FROM ABOUT 10N TO 22N W OF 132W BY 48 HRS. ACTIVE CONVECTION WILL LIKELY PERSIST ACROSS THIS AREA THROUGH SAT MORNING DUE TO FAVORABLE UPPER LEVEL RIDGING AND CONTINUED LOW LEVEL CONVERGENCE ASSOCIATED WITH THE FRESH TO STRONG TRADES. 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