000
AXPZ20 KNHC 152205
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE JAN 15 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 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 10N TO 24N
W OF 120W AS HIGHLIGHTED BY MODEL GUIDANCE...AND AS WAS SUGGESTED
BY A PARTIAL ASCAT PASS FROM 1732/1734 UTC THIS 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 28N132W 
20N130W TO 13N124W TO 09N112W. DIVERGENCE ALOFT TO THE E OF THE 
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.

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. AN ASCAT PASS FROM 1730 UTC THIS 
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...THESE 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 DENSE AND COLD AIR IS FORECAST TO FILTER IN THROUGH THE 
CHIVELA PASS AND GULF OF TEHUANTEPEC IN THE WAKE OF A GULF
OF MEXICO COLD FRONT 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 N 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