000 AXPZ20 KNHC 081536 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1500 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH IS ALONG 09N84W TO 07N90W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N90W TO 05N103W TO 09N122W TO 07N135W TO 08N140W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 07N TO 10N BETWEEN 127W AND 132W. ...DISCUSSION... A STRONG BLOCKING UPPER LEVEL PATTERN IS EVIDENT ON WATER VAPOR IMAGERY THIS MORNING ACROSS THE BROADER REGION N OF 08N BETWEEN 90W AND 145W ANCHORED BY AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED NEAR 12N118W. AN UPPER LEVEL TROUGH IS LOCATED WEST OF THE REGION WITH AXIS ALONG 30N142W TO 10N152W. STRONG AND DIFFLUENT SOUTHWESTERLY MIDDLE TO UPPER LEVEL FLOW ROUNDS THE BASE OF THIS TROUGH AND COVERS A BROAD ZONE OF THE DISCUSSION AREA GENERALLY FROM NORTH OF THE ITCZ AXIS NEAR 07N TO 27N W OF 125W. THIS AREA OF DIFFLUENT FLOW WAS PROVIDING A FAVORABLE ENVIRONMENT FOR WIDELY SCATTERED DEEP CONVECTION FROM 08N TO 22N W OF 130W. OVER THE NORTHEASTERN PERIPHERY OF THE UPPER LEVEL ANTICYCLONE...DRY AND STABLE ATMOSPHERIC CONDITIONS PREVAIL E OF 115W...EXCEPT IN THE VICINITY OF A WEAK TUTT AXIS EXTENDING FROM OVER CENTRAL AMERICA NEAR 14N86W TO 04N101W OVER THE MONSOON TROUGH AXIS ACROSS THE FAR TROPICAL E PACIFIC. THE OVERALL BROAD SCALE PATTERN WILL CHANGE ONLY MODESTLY ACROSS THE DISCUSSION AREA THROUGH THE NEXT 24-48 HOURS AS THIS BROAD LATITUDE RIDGING PREVAILS...CENTERED ON A PERSISTENT UPPER LEVEL HIGH NEAR 13N118W AND EXTENDING N TO 30N. THIS PATTERN WILL CONTINUE TO FORCE SHORTWAVE ENERGY LOCATED TO THE WEST AND NORTHWEST OVER THE NORTHWARD EXTENT OF THE RIDGE AND REMAIN OUTSIDE OF THE AREA...WITH NO FRONTAL BOUNDARIES EXPECTED TO CROSS S OF 32N. GULF OF TEHUANTEPEC...HIGH PRES BUILDING SOUTHWARD 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 FRONT OVER THE NW CARIBBEAN SEA. THE GAP FLOW REACHED GALE FORCE YESTERDAY AND IS NOW BEGINNING TO GRADUALLY DIMINISH IN INTENSITY THROUGH 09/0000 UTC. DOWNSTREAM SEAS CONTINUE IN THE 8 TO 15 FT RANGE AND SHOULD SLOWLY SUBSIDE TO 8-11 FT THROUGH FRIDAY. NEAR THE END OF THE 48 HOUR FORECAST PERIOD HOWEVER...REINFORCING SURFACE RIDGING OVER THE SW GULF OF MEXICO WILL RE-ENERGIZE WINDS TO GALE FORCE ONCE AGAIN SATURDAY MORNING. GULF OF CALIFORNIA...THE PRES GRADIENT IS SLOWLY DECREASING ACROSS THIS AREA...AND WINDS CONTINUE AT 20 KT THROUGH THE AFTERNOON...BUT DIMINISH THEREAFTER WITH SEAS REMAINING LESS THAN 8 FT. FARTHER WEST...A LOW LEVEL SURFACE TROUGH IS ANALYZED FROM 19N TO 23N ALONG 139W...AND MOVING WESTWARD. THE PRES GRADIENT BETWEEN THE TROUGH AND HIGH PRES RIDGING TO THE NORTH WILL MAINTAIN NE TO E WINDS OF 20-25 KT OVER AN AREA FROM 08N TO A LINE FROM 15N120W TO 23N140W W OF 120W WITH SEAS 8 TO 11 FT THROUGH THE NEXT 24 HOURS...AND FROM ABOUT 09N TO A LINE FROM 18N127W TO 24N140W W OF 127W BY 48 HOURS. ACTIVE CONVECTION WILL LIKELY PERSIST ACROSS THIS AREA THROUGH SATURDAY MORNING DUE TO FAVORABLE UPPER LEVEL DIFFLUENCE 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 OF CENTRAL AMERICA. THESE OCCURRENCES SHOULD NOT LAST LONG ENOUGH TO BE INCLUDED IN THE HIGH SEAS FORECAST. $$ HUFFMAN