000
AXPZ20 KNHC 162205
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED JAN 16 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...
THE MONSOON TROUGH EXTENDS FROM 05N78W TO 07N86W TO 05N99W WHERE
LOW LEVEL WINDS SUGGEST IT TRANSITIONS TO THE ITCZ TO 05N108W TO
05N119W TO 08N125W TO 05N140W.  NO SIGNIFICANT IS NOTED.

...DISCUSSION...

BROAD SCALE RIDGING COVERS THE AREA N OF 21N E OF 126W WITH AN
UPPER LEVEL ANTICYCLONE MOVING SEWD AT 32N117W. A STRONG 1040 MB
SURFACE HIGH IS WELL N OF THE DISCUSSION AREA TO THE NW OF THE
U.S. NW COAST. ASSOCIATED RIDGING EXTENDS S THROUGH 32N130W TO 
21N130W TO 17N132W. STRONG HIGH PRES CENTERS ARE ALSO LOCATED 
OVER NRN AND CENTRAL MEXICO WHERE ASSOCIATED STRONG RIDGING IS 
PRESSING SEWD. AS A RESULT...THE PRES GRADIENT IS SIGNIFICANTLY 
INCREASING
ACROSS THE ISTHMUS OF TEHUANTEPEC. A SHARP SURFACE TO LOW LEVEL
TROUGH IS ANALYZED ALONG THE WEST COAST OF MEXICO. THE PRES 
DIFFERENCE BETWEEN IT AND STRONG HIGH PRES OVER THE 
INTER-MOUNTAIN REGION OF
THE U.S. CONTINUE TO BRING NW WINDS OF 20-30 KT THROUGH THE 
GULF OF CALIFORNIA...WITH SEAS OF 8-10 FT NEAR 26N110W. THESE 
WINDS WILL DIMINISH TO 20 KT OR LESS EARLY THU EVENING.

THE PRES DIFFERENCE BETWEEN THE RIDGING OVER THE CENTRAL PORTION 
OF THE AREA AND LOWER PRES TO ITS S IS PRODUCING NE TO E WINDS
20-25 KT FROM 09N TO 24N W OF 120W AS NOTED BY THE 1852 UTC ASCAT
PASS. A 1710 UTC ASCAT PASS CAPTURED AN AREA OF NE 20-25 KT OVER 
THE
FAR ERN PART OF THE AREA FROM 24N TO 29N E OF 119W TO THE COAST 
OF
BAJA CALIFORNIA. THE RIDGE AND ASSOCIATED HIGH CENTER N OF THE 
AREA
IS FORECAST TO WEAKEN OVER THE NEXT 24 TO 48 HRS ALLOWING FOR 
THESE WINDS TO DIMINISH TO 20 KT OR LESS. 

EXPECT TIGHT PRES GRADIENT TO PRODUCE STORM FORCE WINDS IN THE 
GULF OF TEHUANTEPEC BEGINNING THIS EVENING. WINDS WILL INCREASE 
TO 30 KT LATE THIS AFTERNOON AS A COLD FRONT IN WESTERN GULF OF 
MEXICO PUSHES INTO THE BAY OF CAMPECHE THEN CONTINUE TO BUILD TO 
35-50 KT TONIGHT. GFS MODEL GUIDANCE SHOWS 45-50 KT WINDS 
CONTINUING FOR ANOTHER 36 HOURS OR SO UNTIL FRI MORNING...BUT 
GALE CONDITIONS ARE LIKELY TO CONTINUE FOR AN EXTENDED PERIOD 
UNTIL MON MORNING WITH NO SIGNIFICANT CHANGE IN A SYNOPTIC 
PATTERN WITH NORTHERLY WINDS IN THE GULF OF MEXICO AND 
PERSISTENT STRONG PRES GRADIENT IN CENTRAL AMERICA. GULF OF 
PAPAGAYO WILL ALSO EXPERIENCE STRONG PERSISTENT NE WINDS FRI 
THROUGH MON IN THIS SYNOPTIC PATTERN. FRESH TO STRONG E-NE WINDS 
WILL EXTEND FAR DOWNWIND FROM SOURCE REGIONS NEAR TEHUANTEPEC 
AND PAPAGAYO...RESULTING IN VERY LARGE AREA OF ELEVATED SEA 
HEIGHTS IN NE SWELL THU THROUGH SAT NIGHT EXTENDING ROUGHLY FROM 
05N TO 14N E OF 115W.

WAVEWATCH III MODEL GUIDANCE SHOWS 21 SEC LONG PERIOD NW SWELL 
REACHING NW PORTION EARLY SAT MORNING THEN SPREADING ACROSS 
WESTERN WATERS THROUGH TUE WITH LITTLE CHANGE IN WAVE PERIOD 
ALONG LEADING EDGE OF THE SWELL. COASTAL AREAS IN MEXICO WITH NW 
EXPOSURE COULD SEE UNUSUALLY LARGE WAVE HEIGHTS AND BEACH 
EROSION FROM THIS LONG PERIOD SWELL EVENT.

$$
AGUIRRE