000
AXPZ20 KNHC 191613
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT JAN 19 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH FROM 09N75W TO 02N82W TO 07N89W THEN ITCZ TO 
05N98W TO 09N122W TO 08N140W.  SCATTERED MODERATE WITHIN 120 NM 
OF AXIS FROM 116W TO 119W.

...DISCUSSION...
WEAK NEGATIVELY TILTED MIDDLE/UPPER LEVEL TROUGH PERSISTS 
OFFSHORE OF THE W COAST OF N AMERICA TO WEAK MIDDLE/UPPER LEVEL 
CYCLONE NEAR 29N125W BRINGING MINOR INSTABILITY TO NE PORTIONS 
OF REGION AND BAJA CALIFORNIA NORTE. MODEL GUIDANCE DRIFTS 
CYCLONE ALONG 30N INTO NORTHERN BAJA CALIFORNIA WITH SCATTERED 
MODERATE CONVECTION MAINLY ACROSS EASTERN SEMICIRCLE. 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 SE TO NEAR 20N148W. SERIES OF SHORTWAVES 
ROTATING THROUGH BASE AND LIFTING N ACROSS E SIDE SUPPORTING 
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 NW PORTIONS LATE SAT-EARLY SUN 
WITH A VIGOROUS SURFACE LOW PRES 1003 MB SCRAPING ACROSS NW 
PORTIONS...AND SWEEPING A COLD FRONT TO 30N126W...FOLLOWED BY A 
SECONDARY DEVELOPMENT OF LOW PRES ENTERING AREA NEAR 26N139W 
1004 MB SUN AFTERNOON...SHIFTING SLOWLY E-SE TO 25N134.5W BY TUE 
MORNING. THIS WILL PUSH A COLD FRONT WELL E OF THE SECONDARY 
LOW...REACHING ALONG 125W BY TUE. AS THESE TWO DEEP LAYERED LOW 
CENTER MOVE INTO THE AREA...SOUTHERLY GALES ARE POSSIBLE AHEAD 
OF THEM SAT AFTERNOON THROUGH SUN MORNING ACROSS NW 
PORTIONS...AND THEN E OF THE SECOND LOW MON NIGHT AND TUE. LOOK 
FOR  SCATTERED MODERATE CONVECTION ALONG AND WITHIN 240 NM E OF 
FRONT.  

ELSEWHERE AT THE SURFACE...VERY TIGHT PRES GRADIENT ACROSS 
CENTRAL AND SRN MEXICO CONTINUES TO PRODUCE STRONG WIND THROUGH 
CHIVELA PASS...AND REMAIN AT STORM FORCE IN GULF OF 
TEHUANTEPEC...OBSERVED TO 50 KT BY EARLIER OSCAT PASS. MODEL 
GUIDANCE INDICATE A WEAKENING TREND OF THIS GAP WIND 
EVENT...FALLING BELOW STORM FORCE LATE THIS MORNING...WITH GALE 
FORCE WINDS EXPECTED TO CONTINUE IN A NARROWING PLUME THROUGH 
THE WEEKEND.   

STRONG GAP WINDS LIT UP THE COASTAL ZONES OF CENTRAL AMERICA 
OVERNIGHT AS NORTHERLY WIND FLOW SPILLED INTO THE NW AND FAR WRN 
CARIBBEAN BEHIND A STALLED COLD FRONT THERE. NE WINDS 20-25 KT 
WITH ISOLATED AREAS TO 30 KT WERE DEPICTED OVERNIGHT BY A 0336 
UTC ASCAT PASS...PRODUCING FRESH WINDS THROUGH THE GULF OF 
PAPAGAYO AND GULF OF FONSECA. A SIMILAR STRONG N TO NE SURGE 
THROUGH GULF OF PANAMA HAS PUSHED S TO ALONG 05N ACROSS THE FAR 
TROPICAL EPAC...AND IS EXPECTED TO CONTINUE WITH LITTLE CHANGE 
INTO EARLY NEXT WEEK.

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.

$$
STRIPLING