000
AXPZ20 KNHC 160410
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0315 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM 06N78W TO 07N86W TO 05N95W TO
061N103W WHERE LOW LEVEL WINDS SUGGEST IT TRANSITIONS TO THE
ITCZ WHICH EXTENDS TO 08N118W TO 07N130W AND TO BEYOND 05N140W. 
NO SIGNIFICANT CONVECTION IS NOTED.

...DISCUSSION...

A STRONG 1041 MB HIGH CENTER IS ANALYZED WELL N OF THE DISCUSSION
AREA NEAR 47N132W WITH A RIDGE EXTENDING SSE THROUGH 32N126W TO
22N118W TO NEAR 18N112W. THE PRES GRADIENT BETWEEN THE RIDGE 
AND LOWER PRES IN THE VICINITY OF THE ITCZ CONTINUES TO MAINTAIN 
FRESH TO STRONG TRADES GENERALLY OVER AN AREA BOUNDED FROM 10N 
TO 24N W OF 120W AS HIGHLIGHTED BY MODEL GUIDANCE...AND AS WAS 
NOTED IN ASCAT/OSCAT FROM YESTERDAY AFTERNOON. THE HIGH IS 
FORECAST TO REMAIN NEARLY STATIONARY THROUGH THU...BUT WEAKEN 
SLIGHTLY. THIS WILL ALLOW FOR THE AREA OF FRESH TO STRONG TRADES 
TO DIMINISH SOME IN AREAL COVERAGE...AND TO 20 KT OR LESS BY THU 
AFTERNOON.

WATER VAPOR IMAGERY SHOWS A MID/UPPER TROUGH ALONG A POSITION
FROM 27N129W TO 17N125W TO 14N119W TO NEAR 10N110W. AN ASSOCIATED
SURFACE TROUGH IS ANALYZED 13N114W TO 06N118W. DIVERGENCE ALOFT 
E OF THE MID/UPPER TROUGH IS HELPING TO CONSIDERABLY ENHANCE 
ATMOSPHERIC MOISTURE TO ITS E WHERE SCATTERED SHOWERS AND 
ISOLATED TSTMS ARE NOTED FROM 10N TO 19N BETWEEN 110W AND 119W. 
THE UPPER LEVEL CLOUDINESS IS STREAMING NE TO ACROSS WRN AND 
CENTRAL MEXICO. THE MID/UPPER TROUGH WILL GRADUALLY SLIDE 
EASTWARD THROUGH THE NEXT 24-48 HRS WHILE THE SURFACE TROUGH
MOVES WESTWARD.

GULF OF CALIFORNIA...VERY STRONG HIGH PRES OVER THE U.S. GREAT 
BASIN REGION COMBINED WITH WELL DEFINED SURFACE TROUGHING OVER 
WESTERN MEXICO CONTINUES TO MAINTAIN NW TO N WINDS OF UP 30 KT 
THROUGH THE GULF OF CALIFORNIA. ASCAT DATA FROM YESTERDAY 
AFTERNOON INDICATED THAT THERE WAS A PROBABLE INSTANCE OF 
MINIMAL GALE FORCE WINDS DOWNWIND OF THE GULF FROM 22N TO 24N. 
WITH THE PRES GRADIENT THERE EXPECTED TO BEGIN TO WEAKEN OVER 
THE NEXT 48 HRS...THE WINDS WILL RESPOND BY DIMINISHING TO  20 
TO 25 KT BY THU MORNING AND TO 20 KT OR LESS BY THU AFTERNOON. 
HIGH SEA STATE OF 8 TO 11 FT OVER THE CENTRAL AND SRN PORTIONS 
OF THE GULF WILL SUBSIDE TO LESS THAN 8 FT BY THU AFTERNOON.

GAP WINDS...WINDS IN THE GULF OF PAPAGAYO WILL CONTINUE TO PULSE 
OVER THE NEXT COUPLE OF DAYS. WINDS WILL PEAK AT FRESH TO STRONG 
LEVELS DURING THE LATE NIGHT AND EARLY MORNING HOURS WITH THE 
ADDED COMPONENT OF NOCTURNAL DRAINAGE FLOW. WINDS WILL DIMINISH 
TO MODERATE TO FRESH DURING THE AFTERNOON AND EARLY EVENING 
HOURS. 

A SURGE OF COLD AND VERY DENSE AIR IS FORECAST TO FILTER IN 
THROUGH THE CHIVELA PASS AND OVER WARM SEA SURFACE TEMPERATURES
IN THE GULF OF TEHUANTEPEC BEGINNING WED AFTERNOON. THE PRES 
GRADIENT WILL SIGNIFICANTLY BEGIN TO TIGHTEN WED AFTERNOON INTO 
WED EVENING...WITH MODEL GUIDANCE INDICATING THAT THE COLD DENSE 
AIR WILL FUNNEL IN AS N TO NE GALE FORCE WINDS OF UP TO 40 KT 
WED EVENING. THESE WINDS THEN INCREASE TO STORM FORCE OF 40 TO 
50 KT BY LATE WED NIGHT...AND ARE EXPECTED TO CONTINUE AT OR 
JUST BELOW STORM STRENGTH BY EARLY THU AFTERNOON.

$$
AGUIRRE