000 AXPZ20 KNHC 070345 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC FRI JAN 07 2011 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0315 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE AXIS CENTERED FROM 5N79W 1009 MB TO 5N91W TO 8N100W TO 6N113W TO 10N122W TO 9N130W TO 7N140W. NO SIGNIFICANT CONVECTION IS NOTED. ...DISCUSSION... AN ILL-DEFINED TROUGH EXTENDS FROM 24N123W TO 19N126W. SATELLITE WATER VAPOR IMAGERY SHOWS AND UPPER LEVEL LOW LIFTING NE JUST N OF THE AREA NEAR 32N126W WITH ITS ASSOCIATED TROUGH SW TO 24N130W TO 18N132W. THE LOW IS FORECAST TO MOVE ACROSS THE CALIFORNIA COASTLINE ON FRIDAY BEFORE IT MOVES INLAND THE SW U.S. A SURFACE RIDGE EXTENDS FROM A 1026 MB HIGH CENTERED N OF THE AREA NEAR 38N120W SW TO JUST W OF THE AREA NEAR 20N142W. WINDS ASSOCIATED WITH THE LOW HAVE DIMINISHED TO LESS THAN 20 KT...HOWEVER AN INTENSIFYING 996 MB LOW CENTERED NW OF THE AREA NEAR 31N149W IS MOVING NNE AT AROUND 10 KT WITH ITS ASSOCIATED COLD FRONT MOVING ESE AT 15 KT. SEAS UP TO 11 FT IN LARGE NW SWELLS ARE AFFECTING THE FAR WESTERN PORTION OF THE AREA N OF 20N AND W OF 137W WHERE SE-S WINDS OF 20-25 KT ARE ALSO FOUND. ELSEWHERE A RELATIVELY PRES GRADIENT EXISTS THROUGHOUT...WITH THE EXCEPTION OF THE CENTRAL PORTION OF THE REGION FROM 7N TO 15N BETWEEN 120W AND 129W WHERE THE GRADIENT HAS TIGHTENED BETWEEN A SURFACE TROUGH ALONG 13N121W 9N124W AND RIDGING TO THE N. NE-E WINDS OF 20-25 KT WINDS ARE W OF THE TROUGH TO A LINE FROM 14N126W TO 7N131W WHERE SEAS ARE IN THE RANGE OF 8-10 FT. SATELLITE IMAGERY SHOWS EXTENSIVE MID/UPPER LEVEL MOISTURE ADVECTING NORTHEASTWARD ACROSS THE TROUGH BETWEEN THE MID/UPPER TROUGH MENTIONED ABOVE AND AN UPPER LEVEL ANTICYLONE ANCHORED NEAR 13N105W. MODERATE SW FLOW ASSOCIATED WITH BROAD ANTICYCLONIC SE OF THE MID/UPPER LEVEL TROUGH IS PUSHING THIS MOISTURE NE TO WELL INLAND THE MEXICO AND THE SW U.S. POSSIBLE AREAS OF RAIN ALONG WITH EMBEDDED SCATTERED SHOWERS ARE WITHIN THE AREA OF CLOUDINESS. DURING THE NEXT 48 HOURS...MODELS FORECAST SURFACE RIDGING TO BUILD OVER THE EASTERN PART OF THE AREA N OF 20N AND STRENGTHEN. THIS WILL PRODUCE A TIGHTENING PRES GRADIENT W OF BAJA CALIFORNIA INCREASING NW WINDS TO 20 KT WITHIN 180 NM OF THE COAST BY SAT. STRONG HIGH PRES OVER THE GREAT BASIN REGION COMBINED WITH LOW PRESSURE OVER SW MEXICO IS CREATING A PRESSURE GRADIENT WHICH IS SUPPORTING NW WINDS OF 20-25 KT THROUGH THE GULF OF CALIFORNIA. AS THE HIGH PRES OVER THE GREAT BASIN REGION WEAKENS OVER THE NEXT 48 HOURS...THE PRES GRADIENT WILL RELAX WITH WINDS LESSENING FROM N TO S. A RATHER WEAK STATIONARY 1007 MB LOW IS OVER THE FAR EASTERN PORTION OF THE AREA CENTERED NEAR 5N80W. THE LOW IS HELPING TO PULL IN LIGHT NLY FLOW FROM ACROSS PANAMA SOUTHWARD TO 4N BETWEEN 78W AND 80W. ANOTHER LOW...WITH A BETTER DEFINED CIRCULATION...IS ALONG THE ITCZ AXIS NEAR 8N102W WITH A PRES OF 1008 MB. THE LOW IS VOID OF DEEP CONVECTION WITH ONLY ISOLATED SHOWERS NOTED WITHIN 120 NM IN THE N SEMICIRCLE. IT IS FORECAST BY THE GLOBAL MODELS TO MOVE IN A WNW MOTION OVER THE NEXT 48 HOURS WITH NO SIGNIFICANT WINDS. GAP WINDS... HIGH PRES BUILDING SE ACROSS MEXICO IS USHERING IN A DENSER AIR MASS ACROSS THIS AREA. THIS HAS BEGUN TO FILTER THROUGH THE CHIVELA PASS AND INTO THE GULF OF TEHUANTEPEC...RESULTING IN N WINDS OF 20-30 KT WITH SEAS OF 8-10 FT AS REPORTED BY SHIP OBSERVATIONS IN THAT AREA. A RATHER PROGRESSIVE UPPER LEVEL LEVEL PATTERN WILL QUICKLY SHIFT THE DENSER AIR MASS EASTWARD AND INTO THE CENTRAL GULF OF MEXICO BY 24 HOURS. THIS WILL RESULT IN SE RETURN FLOW DEVELOPING OVER THE WESTERN GULF OF MEXICO...AND DIMINISH THE WINDS FUNNELING THROUGH THE CHIVELA PASS. WINDS ARE EXPECTED TO DIMINISH TO BELOW 20 KT BY 36 HOURS WITH SEAS DROPPING TO BELOW 8 FT. NE TO E WINDS OF 20 KT ARE EXPECTED TO START UP AGAIN THROUGH THE GULF OF PAPAGAYO IN ABOUT 12 HOURS...BUT SHOULD BE SHORT LIVED NOT EXPECTED TO CONTINUE BEYOND 24 HOURS. $$ AGUIRRE