000 AXPZ20 KNHC 301604 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC SUN DEC 30 2012 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 0945 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 08N77W TO 08N101W. THE ITCZ EXTENDS FROM 08N101W TO 09N121W TO 06N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION FROM 05N TO 07N E OF 90W. SCATTERED MODERATE TO STRONG CONVECTION FROM 11N TO 15N BETWEEN 11W AND 120W. ...DISCUSSION... ALOFT...A VIGOROUS UPPER TROUGH EXTENDS ACROSS THE DISCUSSION AREA FROM 32N120W TO A BASE OVER THE DEEP TROPICS AT 09N137W. AN UPPER RIDGE AXIS IS OVER THE FAR NW PORTION WITH UPPER MOISTURE SPILLING ACROSS THE RIDGE AXIS OVER THE AREA N OF 26N W OF 136W. OTHERWISE VERY DRY UPPER AIR IS INDICATED W OF THE TROUGH AXIS. UPPER LEVEL ANTICYCLONES ARE CENTERED OVER COLOMBIA AT 07N72W AND OVER THE NW CARIBBEAN AT 18N82W. AN UPPER RIDGE EXTENDS NW THROUGH THESE ANTICYCLONES ACROSS OLD MEXICO AND NEW MEXICO EVENTUALLY CRESTING WELL N OF THE AREA OVER THE DAKOTAS. BROAD ANTICYCLONIC UPPER WESTERLY FLOW IS OBSERVED OVER THE DEEP TROPICS S OF 07N BETWEEN 118-133W AND COMBINES WITH THE LARGE UPPER TROUGH AND RIDGE PATTERN PREVIOUSLY DESCRIBED TO SET UP AN AREA OF WEAK UPPER DIFFLUENCE SUPPORTING THE ITCZ CONVECTION BETWEEN 110-130W. THE RESULTANT UPPER DEBRIS MOISTURE IS ADVECTED NE ALONG THE PERIPHERY OF THE RIDGE BETWEEN 106-120W... THEN THE MOISTURE FANS OUT AS IT CONTINUES NE ACROSS NORTHERN OLD MEXICO. SOME OF THE MOISTURE SPREADS N ACROSS ARIZONA AND NEW MEXICO...WHILE SOME OF THE MOISTURE TURNS E INTO A NARROW PLUME STREAMING E ACROSS THE NORTHERN GULF OF MEXICO. AN UPPER CYCLONE HAS FORMED OVER THE DEEP TROPICAL PACIFIC NEAR 06N95W WITH AN UPPER TROUGH EXTENDING E TO 05N77W. WEAK UPPER DIFFLUENCE IS INDUCED BETWEEN THIS TROUGH AND THE UPPER RIDGE DESCRIBED TO THE N OVER CENTRAL AMERICA...AND IS SUPPORTING THE CLUSTERS OF CONVECTION ALONG THE MONSOON TROUGH AS PREVIOUSLY DESCRIBED. THE SURROUNDING UPPER LEVELS ARE DRY AND THE DEBRIS MOISTURE SEEMS TO QUICKLY EVAPORATE NEAR THE DECAYING CELLS. LOW LEVELS...A SURFACE RIDGE EXTENDS SE ACROSS THE AREA FROM 32N140W TO TO 22N109W. A COLD FRONT IS WEAKENING AS IT MOVES ACROSS THE NORTHERN BAJA PENINSULA. EXPECT THE FRONT TO CONTINUE TO WEAKEN AS IT MOVES ACROSS THE GULF OF CALIFORNIA TONIGHT. ANTICYCLONIC 10-15 KT WINDS ARE OBSERVED ACROSS THE SUB-TROPICS...EXCEPT FOR A SMALL AREA OF NW 15-20 KT WINDS IN THE WAKE OF THE FRONT NEAR 29N124W. SEAS ARE 7-12 FT IN MIXING N...NE...AND NW SWELL. THE NE TRADES S OF THE SURFACE RIDGE FROM 08-22N BETWEEN 127-140W CONTINUE AT 20-25 KT WITH SEAS 9-12 FT IN MIXED NE AND NW SWELL. ELSEWHERE W OF LINE FROM 26N115W TO 15N115W TO 07N140W SURFACE WINDS ARE N TO NE AT 10-20 KT WITH SEAS 8-10 FT PRIMARILY DUE TO MIXING LONG PERIOD NE AND NW SWELL. A SURFACE HIGH WILL SHIFT S INTO THE AREA NEAR 30N130W LATE MON MAINTAINING THE NE TRADES IN THE AREA FROM 08-20N W OF 130W WITH SEAS 9-12 FT IN MIXED NE AND NW SWELL. LARGE LONG PERIOD NW SWELL WILL PROPAGATE INTO THE FAR NW PACIFIC WATERS TONIGHT DRIVING SEAS UP TO 13 FT. THESE NW SWELLS WILL CONTINUE EASTWARD BUT GRADUALLY SUBSIDE WITH SEAS OF 7-10 FT REACHING THE NORTHERN BAJA PENINSULA LATE TUE NIGHT...AND REACHING THE SOUTHERN BAJA PENINSULA LATE WED NIGHT. A COLD FRONT WILL ENTER THE WATERS NEAR 30N140W TUE NIGHT ACCOMPANIED BY A 20-25 KT SW-NW WIND SHIFT WITH SOUTHERLY GALE WINDS PRECEDING THE FRONT OVER THE WATERS N OF 31N. GULF OF TEHUANTEPEC...THE WESTERN PORTION OF A SWATH OF RECENT HIGH RESOLUTION ASCAT WINDS DETECT N-NW 35 KT WINDS OVER THE EASTERN WATERS OF THE GULF OF TEHUANTEPEC. EXPECT STRONG N FLOW W OF RECENT ASCAT SWATH...THUS A MINIMAL STORM FORCE WARNING IS IN EFFECT THROUGH MID MORNING TODAY WITH GALE FORCE CONTINUING THROUGH SUNRISE MON...WITH THE NORTHERLY WINDS DIMINISHING BELOW 20 KT LATE MON. GULF OF PAPAGAYO...NE-E 15-25 KT SURGES ARE EXPECTED TO CONTINUE AND GRADUALLY SPREAD AS FAR W AS 94W BY TONIGHT WHERE THE ASSOCIATED NE SWELLS WILL THEN MIX WITH SW CROSS EQUATORIAL SWELL AS WELL AS N SWELL PROPAGATING S FROM THE STRONG TEHUANTEPEC EVENT. GULF OF CALIFORNIA...LIGHT AND VARIABLE WINDS INDICATED EXCEPT A 15-20 KT SW-W-NW WIND SHIFT IS EXPECTED OVER THE NORTHERN WATERS AS THE WEAKENING COLD FRONT PASSES TODAY-TONIGHT. NW WINDS AT 10-15 KT EXPECTED MOST WATERS BY MON NIGHT AND INCREASING TO 20-25 KT ACROSS THE GULF WATERS N OF 25N LATE TUE. $$ MUNDELL