000 AXPZ20 KNHC 072205 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC WED NOV 07 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS W ACROSS THE SOUTHWESTERN CARIBBEAN ALONG 11N...THEN TURNS ABRUPTLY SW ACROSS THE PANAMA AND COSTA RICA BORDER TO THE PACIFIC COAST AT 09N84W..THEN SW TO 07N90W... THEN TURNS W TO 08N97W WHERE LOW LEVEL WINDS INDICATE A TRANSITION TO AN ITCZ WHICH CONTINUES W THROUGH 09N103W TO BEYOND 08N140W. SCATTERED MODERATE CONVECTION...WITH A FEW STRONG CLUSTERS VERIFIED BY LIGHTNING DATA...IS NOTED WITHIN 180 NM EITHER SIDE OF A LINE FROM 06N82W TO 10N100W TO 11N114W. ...DISCUSSION... A PAIR OF UPPER CYCLONES ARE CENTERED AT 29N127W AND 25N129W WITH AN UPPER TROUGH EXTENDING S THROUGH THE CYCLONES TO A BASE OVER THE DEEP TROPICS AT 10N123W. AN ASSOCIATED 1018 MB SURFACE LOW IS ANALYZED AT 30N127W WITH A BROKEN-OVERCAST STRATOCUMULUS FIELD OBSERVED WITHIN 150 NM OVER ITS NW SEMICIRCLE. AN UPPER LEVEL ANTICYCLONE IS AT 11N94W WITH AN UPPER RIDGE EXTENDING NW ACROSS WESTERN OLD MEXICO TO A CREST OVER ARIZONA AT 35N112W. A MOISTURE PLUME IS OBSERVED FROM 20N-30N BETWEEN 120W-107W...AND IS ADVECTED NE AND E ACROSS THE RIDGE AXIS AND ACROSS NORTHERN OLD MEXICO. UPPER DIFFLUENCE IS NOTED FURTHER S AND IS ROUGHLY IN PHASE WITH THE CONVECTION PREVIOUSLY DESCRIBED. THE RESULTANT DEBRIS MOISTURE IS ADVECTED N AND NE IN THE UPPER ANTICYCLONIC FLOW...BUT EVAPORATES BEFORE MOVING ACROSS CENTRAL AMERICA. THE UPPER CYCLONES ARE EXPECTED TO FILL RAPIDLY TONIGHT AS THE PARENT UPPER TROUGH TO THEIR N PROGRESSES E ACROSS THE WESTERN SEABOARD OF THE CONUS. THE SURFACE LOW WILL WEAKEN TO A TROUGH AND SHIFT E ACROSS THE NE PORTION OF THE AREA ACCOMPANIED BY ONLY A 5-10 KT SW-W-NW WIND SHIFT. ANOTHER UPPER CYCLONE IS CURRENTLY W OF THE AREA AT 27N145W...AND WILL GET PICKED UP BY A SECONDARY UPPER SHORTWAVE TROUGH THAT WILL SWING SE INTO THE NW CORNER OF THE DISCUSSION AREA ON THU...AND CONTINUE E ACROSS THE N-CENTRAL PORTION ON FRI. A SURFACE RIDGE WILL BUILD E ACROSS THE NORTHERN WATERS IN BEGINNING LATE TONIGHT...RESULTING IN NE LOW WINDS INCREASING TO 20-25 KT AND SEAS 7-10 FT DEVELOPING OVER THE WATERS N OF 28N W OF 133W ON THU AND SPREADING S TO ALONG 25N ON FRI. THE INCREASING PRESSURE GRADIENT WILL ARRIVE THE W COAST OF THE BAJA PENINSULA IN THE FORM OF NW 15-20 KT ON FRI NIGHT...WITH SEAS OF 6-8 FT IN NW SWELL ARRIVING ON SAT NIGHT. THESE CONDITIONS WILL SPREAD S ALONG THE ENTIRE W COAST OF BAJA BY MIDDAY SUN. GAP WINDS...A SCATTEROMETER PASS EARLIER TODAY VERIFIED NOT ONLY THE GALE CONDITIONS IN AND DOWNSTREAM OF THE GULF OF TEHUANTEPEC BUT NORTHERLY WINDS OF 20-25 KT JUST DOWNSTREAM OF THE GULF OF FONSECA. THE WINDS NEAR TEHUANTEPEC ARE EXPECTED TO INCREASE 30-40 KT TONIGHT THROUGH THU WITH SEAS BUILDING TO 14 FT. THE GALE CONDITIONS ARE EXPECTED TO PERSIST THROUGH SUNRISE FRI MORNING...THEN DIMINISH WITH ONE LAST SURGE TO 30 KT LATE FRI NIGHT INTO EARLY SAT MORNING. EXPECT THE NE WINDS IN AND DOWNSTREAM OF THE GULF OF PAPAGAYO TO PULSE THROUGH SUN AFTERNOON. THE RESULTANT NE SWELL WILL PROPAGATE W TO ALONG 94W...MERGING WITH THE SWELL ORIGINATING FROM THE NORTHERLY WINDS SURGING THROUGH THE GULF OF TEHUANTEPEC. BEST GUESS FOR NOW IS THE NEXT GALE EVENT SETTING UP FOR MON NIGHT IN THE GULF OF TEHUANTEPEC. CROSS EQUATORIAL SOUTHERLY SWELL...RESULTING IN SEAS TO 8 FT... ARE NOTED ACROSS THE DEEP TROPICS S OF 07N TO THE W OF 97W. THE AREA OF SOUTHERLY SWELLS IS EXPECTED TO SHRINK TO ONLY BETWEEN 98W-118W ON THU AND SUBSIDE BELOW 8 FT ON FRI. NOTE THAT SOME THIS SWELL WILL MIX WITH THE SHORTER PERIOD NE SWELL PROPAGATING SW AND W FROM THE GULF OF TEHUANTEPEC GALE EVENT RESULTING IN AN AREA OF MIXED NE AND SW SWELL WITH SEAS OF 8-10 FT THU AND FRI. $$ NELSON