000 AXPZ20 KNHC 202204 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SUN JAN 20 2013 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... MONSOON TROUGH EXTENDS FROM 08N75W TO 02N81W TO 08N87W TO 07N91W WHERE LOW LEVEL WINDS SUGGEST THAT IT TRANSITIONS TO THE ITCZ TO 06N97W TO 07N105W TO 07N114W TO 09N130W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM N OF THE ITCZ BETWEEN 99W-102W.. ...DISCUSSION... A SMALL AND WEAK MID TO UPPER LEVEL CYCLONE NEAR 31N118W IS SLOWLY SHIFTING EWD...WITH A TROUGH SSE TO 22N112W THEN S TO 15N112W AND TO 07N112W. THE TROUGH IS LIFTING NEWD OVER A SHARP UPPER RIDGE TO ITS E ROUGHLY ALONG 95W N OF 06N. UPPER DIVERGENCE AT BASE OF TROUGH ACTING TO ENHANCE CONVECTION N OF ITCZ BETWEEN 99W-102W. A SHARP SHORTWAVE RIDGE IS TO THE W OF THE TROUGH ALONG 126N AND N OF ABOUT 14N. A NEGATIVE TILED LONGWAVE DEEP LAYERED TROUGH EXTENDS FROM THE NE PACIFIC SSE TO VIGOROUS VORTEX NEAR 26N140W...WITH A TROUGH EXTENDING SW TO A BROAD BASE NEAR 11N145W. SATELLITE DERIVED WINDS DEPICTS A 75-100 KT UPPER JET STREAM BRANCH ACROSS THE SE SEMICIRCLE OF THE VORTEX. AT THE SURFACE...AN OLD COLD FRONTAL BOUNDARY LINGERS AHEAD OF THIS EWD DRIFTING LONGWAVE TROUGH...AND STRETCHES FROM 32N138W TO 25N136W TO 16N137W TO SW OF THE AREA OF 11N140W. A BROAD ZONE OF UPPER DIVERGENCE E OF TROUGH WITH UPPER LEVEL DIFFLUENCE IN PLACE CONTINUES TO ENHANCE MOSTLY SCATTERED CONVECTION ALONG AND TO WITHIN 360 NM W OF THE COLD FRONT N OF 17N. IT IS LIKELY INDUCING ISOLATED AREAS OF GALE FORCE WINDS NEAR AND WITHIN THE DEEPER CONVECTION AS WAS SUGGEST BY AN ASCAT PASS FROM JUST PAST 19 UTC THIS AFTERNOON. SE TO S WINDS 20-30 KT PREVAIL WITHIN 300 NM E OF FRONT...WITH GALES OCCURRING N OF 30N AND OUT OF DISCUSSION AREA. A SURFACE LOW ASSOCIATED WITH THE UPPER VORTEX IS NEAR 26N141W WITH A PRES OF 1003 MB MOVING E. THE LONG WAVE TROUGH AND ATTENDANT SURFACE LOW WILL SHIFT GRADUALLY E OVER THE NEXT 48 HOURS AND REMAIN NEGATIVELY TILTED FOR ACTIVE CONVECTION SE SEMICIRCLE ...WITH COMPLEX SURFACE LOW SHIFTING SLOWLY E TO SE IN UNISON. SLIGHT CHANCE FOR GALES IN SMALL ISOLATED AREAS NEAR DEEPER CONVECTION ALONG FRONT...AND ALSO IN THE NW QUADRANT OF LOW BY TUE. HIGH SEAS IN THE RANGE OF 11-17 FT WILL PERSIST ACROSS THE NW PORTION OF THE AREA THROUGH TUE AS LARGE NW SWELL PROPAGATING THROUGH THE REGION PASSES THROUGH THIS AREA OF MIXED SWELL CREATED BY SURFACE LOW. VERY LONG PERIOD NW SWELL IS CURRENTLY MOVING THROUGH W HALF OF DISCUSSION AREA...AND HAS BEGUN TO PEAK ACROSS BAJA CALIFORNIA NORTE. BUOY 46047 LOCATED 120 NM W OF SAN DIEGO REPORTED SWELL OF 10 FT AND 23 SECONDS LAST NIGHT THAT IS NOW REACHING BAJA CALIFORNIA. LONGER PERIOD FORERUNNERS ARE MOVING OFFSHORE OF MEXICO AND W PORTIONS OF CENTRAL AMERICA ATTM...AND WILL ALSO PEAK IN THE NEXT 48 HOURS. EXPOSED REEFS AND COASTS WITH NW EXPOSURE WILL SEE VERY SIGNIFICANT WAVE ENERGY...AND PRODUCE VERY STRONG AND POWERFUL SURF...WIDESPREAD RIP CURRENTS...AND COASTAL EROSION DURING HIGH TIDES. ELSEWHERE AT THE LOW LEVELS... CONTINUED NORTHEASTERLY WINDS IN SW GULF OF MEXICO ARE MOVING ACROSS CHIVELA PASS AND BRINGING GALE FORCE N-NE WINDS INTO GULF OF TEHUANTEPEC. WINDS ARE EXPECTED TO DIMINISH THROUGH THE NEXT 24 HOURS...TO MINIMAL GALES...AND PERSIST THROUGH MON NIGHT. NEXT BLAST OF COLD AIR IN GULF OF MEXICO INCREASES WINDS AGAIN LATE IN FORECAST PERIOD. CURRENT GALE FORCE WINDS OVER SW CARIBBEAN REINFORCE FRESH TO STRONG NE WINDS ALONG GULFS OF PAPAGAYO AND FONSECA THROUGH FORECAST PERIOD WITH STRONGEST WINDS NOTED IN EARLY MORNINGS AS DOWNSLOPE DRAINAGE WINDS ADD STRENGTH TO WIND FIELD. STRONG NE WINDS ACROSS SW CARIBBEAN ALSO CONTRIBUTES TO FRESH N BREEZE OVER GULF OF PANAMA THROUGH LATE MON. $$ AGUIRRE