000
AXPZ20 KNHC 151507
TWDEP 

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

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM 08N84W TO 06N100W WHERE LOW 
LEVEL WINDS SUGGEST A TRANSITION TO ITCZ WHICH EXTENDS TO 
08N120W TO BEYOND 05N140W. SCATTERED MODERATE CONVECTION WAS 
NOTED FROM 10N TO 12N BETWEEN 113W AND 118W.

...DISCUSSION...
STRONG 1041 MB HIGH PRES IS CENTERED WELL N OF THE DISCUSSION 
WATERS NEAR 47N132W WITH A RIDGE EXTENDING SE THROUGH TO NEAR 
18N110W. THE PRES GRADIENT BETWEEN THIS RIDGE AND LOWER PRES IN 
THE VICINITY OF THE ITCZ CONTINUES TO MAINTAIN FRESH TO STRONG 
TRADES GENERALLY FROM 10N TO 20N W OF 120W AS DEPICTED BY THE 
LATEST SCATTEROMETER DATA. THE AREA OF HIGH PRES WILL WEAKEN 
OVER THE NEXT COUPLE OF DAYS. THIS WILL SLACKEN THE PRES 
GRADIENT AND THE AREA OF STRONG TRADES WILL DIMINISH TO 20 KT OR 
LESS BY WED MORNING.

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 FRESH TO NEAR GALE FORCE NW 
WINDS DOWN THE ENTIRE LENGTH OF THE GULF OF CALIFORNIA. GUIDANCE 
DEVELOPED AROUND A LOCAL RESEARCH STUDY CONTINUES TO INDICATE 
AROUND A 25 PERCENT PROBABILITY OF GALE CONDITIONS IN THE GULF 
WITH THE HIGHEST CHANCES TONIGHT INTO EARLY WED. WINDS IN THE 
FORECAST WILL REMAIN CAPPED AT 30 KT UNLESS PROBABILITIES FOR 34 
KT WINDS INCREASE A BIT HIGHER. THE AREA OF HIGH PRESSURE WILL 
WEAKEN BY THU MORNING WHICH WILL START TO DECREASE THE WINDS 
OVER THE GULF OF CALIFORNIA...WITH STRONG 25 KT WINDS MAINLY 
CONFINED TO N OF 27N BY THU MORNING.

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 AIR IS FORECAST TO ARRIVE BEHIND A COLD FRONT IN 
THE GULF OF MEXICO WED INTO THU. THE PRES GRADIENT WILL TIGHTEN 
WED AFTERNOON ALLOWING FOR NORTHERLY WINDS TO INCREASE TO FRESH 
TO STRONG AHEAD OF THE ARRIVAL OF THE FRONT. ONCE THE FRONT 
CLEARS THE SW GULF OF MEXICO...NORTHERLY WINDS WILL RAPIDLY BE 
FUNNELED THROUGH THE CHIVELA PASS ACROSS THE GULF OF TEHUANTEPEC 
AREA...WITH A GALE WARNING NOW IN EFFECT BEGINNING AT 00 UTC 
THU. MODEL GUIDANCE CONTINUES TO HINT AT THE POTENTIAL FOR 
MINIMAL STORM FORCE WINDS BY THU AFTERNOON SO THE GALE WARNING 
MAY NEED TO BE UPGRADED TO A STORM WARNING IF CURRENT TRENDS 
CONTINUE.

$$
AL