000
AXPZ20 KNHC 200342
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0330 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM 09N75W TO 02N82W TO 06N91W...WHERE
LOW LEVEL WINDS SUGGEST IT THEN TRANSITIONS TO ITCZ TO 06N103W 
TO 09N110W TO 06N123W TO 08N132W TO 09N140W. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION EXISTS FROM 07N TO 11N 
BETWEEN 105W-111W.

...DISCUSSION...

A WEAK NEGATIVELY-TILTED MID/UPPER LEVEL TROUGH PERSISTS 
OFFSHORE OF THE W COAST OF N AMERICA TO A WEAK MIDDLE/UPPER 
LEVEL CYCLONE LIFTING NE NEAR 30N123W. A TROUGH CONTINUES S 
FROM THE CYCLONE SE TO 22N121W TO 11N115W. AN AMPLIFYING RIDGE
IS TO ITS E. DIFFLUENT FLOW PATTERN ALOFT BETWEEN THE TROUGH
AND RIDGE IS SIGNIFICANTLY ENHANCING DEEP ATMOSPHERIC MOISTURE 
OVER THE ERN PORTION OF THE AREA FROM 11N TO 21N BETWEEN 110W AND
115W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN THIS AREA
OF MOISTURE. THIS AREA OF MOSITURE WILL CHANGE LITTLE THROUGH SUN
...THEN BEGIN TO BREAK UP MON AS RIDGING MOVES ACROSS THE ERN
PART OF THE AREA AHEAD OF CYCLONE/FRONTAL SYSTEM MENTIONED BELOW.

MODEL GUIDANCE DRIFTS CYCLONE ALONG 30N INTO NRN BAJA CALIFORNIA 
THROUGH MON. NARROW SHORTWAVE RIDGES ARE FOUND ON EITHER SIDE OF 
TROUGH...BOTH N OF 25N. VERY ENERGETIC NEGATIVE TILT LONGWAVE 
UPPER LEVEL TROUGH W OF AREA EXTENDS SEWD TO NEAR 20N145W. A 
SERIES OF SHORTWAVES ROTATING THROUGH THE BASE AND LIFTING N 
ACROSS ITS E SIDE SUPPORT A SERIES OF ADVANCING COLD FRONTS JUST 
W OF AREA BETWEEN 141W AND 151W...ALONG 30N.

A STRONG DEEP LAYER CYCLONE ASSOCIATED WITH THIS LONG WAVE 
TROUGH IS FORECAST TO MOVE ACROSS THE NW PORTION OF THE AREA
LATE TONIGHT INTO EARLY SUN WITH A PRONOUNCED SURFACE LOW OF
AROUND 1003 MB MOVING INTO THE FAR WRN PORTION OF THE AREA NEAR 
26N139W BY EARLY SUN EVENING. THE LOW IS FORECAST TO EXTEND AN 
OCCLUDED FRONT TO 29N138W TO 24N137W...THEN TRANSITION TO A COLD 
FRONT TO 15N140W. BY EARLY MON AFTERNOON...THE LOW IS FORECAST 
TO BE NEAR 25N136W AS 1003 MB WITH THE OCCLUDED FRONT TO EXTEND 
TO 29N135W TO 26N133W...THEN AS COLD FRONT TO NEAR 21N140W. SE 
TO S WINDS WILL APPROACH 30 KT AND TO POSSIBLE GALE FORCE AHEAD 
OF THE FRONT N OF ABOUT 21N. SCATTERED MODERATE CONVECTION IS 
EXPECTED ALONG AND WITHIN 240 NM E OF THE FRONT N OF ABOUT 24N.  

ELSEWHERE AT THE SURFACE...A TIGHT PRES GRADIENT ACROSS CENTRAL 
AND SRN MEXICO CONTINUES TO PRODUCE STRONG N TO NE WINDS THROUGH 
THE CHIVELA PASS...AND INTO THE GULF OF TEHUANTEPEC. THE STORM 
FORCE CONDITIONS ARE SLOWLY SUBSIDING TO GALE FORCE. THE GALE 
FORCE WINDS WILL REMAIN IN A SHRINKING AREA INTO EARLY NEXT WEEK.

NE 20 TO 30 KT WINDS WILL CONTINUE THROUGH THE GULF OF PAPAGAYO 
SUN EVENING THEN DIMINISH SLIGHTLY MON. N TO NE WINDS OF 20 TO 
25 KT WILL CONTINUE THROUGH GULF OF FONSECA THROUGH SUN. N TO NE 
20 TO 25 KT WINDS THROUGH THE GULF OF PANAMA AND BETWEEN 79W AND 
81W N OF 05N WILL PERSIST THROUGH MON.

A VERY STRONG NW SWELL EVENT HAS MOVED THROUGH THE CENTRAL 
PACIFIC AND HAWAIIAN ISLANDS IN THE PAST FEW DAYS...AND IS NOW 
ENTERING NW PORTIONS OF THE AREA WATERS...WITH FORERUNNER NW 
SWELL OF 25-27 SECONDS NOW REACHING SOUTHERN CALIFORNIA AND N 
BAJA CALIFORNIA. THESE SWELLS WILL SPREAD QUICKLY SE INTO THE 
REGIONAL WATERS DURING THE NEXT 24 HOURS TO PRODUCE VERY STRONG 
AND POWERFUL SURF ALONG EXPOSED REEFS AND COASTLINES...AND 
GENERATE EXTREMELY DANGEROUS RIP CURRENTS AND WIDESPREAD BEACH 
EROSION.

$$
AGUIRRE