000
AXPZ20 KNHC 141524
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON JAN 14 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 06N77W TO 06N94W WHERE LOW LEVEL 
WINDS SUGGEST A TRANSITION TO ITCZ EXTENDING TO 09N120W TO 
BEYOND 05N140W. SCATTERED MODERATE TO STRONG CONVECTION WAS 
NOTED WITHIN 90 NM N AND 60 NM S OF AXIS BETWEEN 123W TO 131W.

...DISCUSSION...
STRONG 1040 MB HIGH PRES IS CENTERED NEAR 45N137W WITH RIDGE 
EXTENDING SE TO NEAR 23N114W. THE PRES GRADIENT BETWEEN THIS 
RIDGE AND LOWER PRES IN THE VICINITY OF THE ITCZ ACROSS THE W 
CENTRAL WATERS IS MAINTAINING FRESH TO STRONG TRADES GENERALLY 
FROM 07 TO 20N W OF 130W AND FROM 09N TO 15N BETWEEN 120W AND 
130W AS DEPICTED BY THE LATEST SCATTEROMETER DATA. THE AREA OF 
HIGH PRES WILL DRIFT NORTHWARD WHILE GRADUALLY WEAKENING OVER 
THE NEXT COUPLE OF DAYS. THIS WILL SLACKEN THE PRES GRADIENT AND 
DECREASE THE AREAL COVERAGE OF THE STRONG TRADEWIND FLOW OVER 
THE W CENTRAL WATERS SIGNIFICANTLY BY MIDWEEK.

A WEAK SURFACE TROUGH IS EMBEDDED IN THE ITCZ FROM 11N123W TO 
05N125. THIS TROUGH WILL MOVE WESTWARD WHILE WEAKENING THE NEXT 
COUPLE DAYS. THIS FEATURE IS HELPING TO MAINTAIN THE STRONG 
TRADES CURRENTLY...BUT ITS WEAKENING WILL ALSO BE A FACTOR IN 
DIMINISHING TRADES BY MIDWEEK. 

GULF OF CALIFORNIA...VERY STRONG HIGH PRES WILL CONTINUE TO 
BUILD ACROSS THE U.S. GREAT BASIN REGION. THIS COMBINED WITH 
WELL DEFINED SURFACE TROUGHING OVER WESTERN MEXICO WILL RESULT 
IN STRONG TO NEAR GALE FORCE NW WINDS DOWN THE ENTIRE LENGTH OF 
THE GULF OF CALIFORNIA BY MON EVENING WITH SEAS UP TO 11 FT 
SPILLING OUT OF THE SOUTHERN GULF. GUIDANCE DEVELOPED AROUND A 
LOCAL RESEARCH STUDY CONTINUES TO INDICATE AROUND A 25-50 
PERCENT PROBABILITY OF GALE CONDITIONS IN THE GULF. WINDS IN THE 
FORECAST WILL REMAIN CAPPED AT 30 KT UNLESS PROBABILITIES FOR 35 
KT WINDS INCREASE A BIT HIGHER.

GAP WINDS...WINDS WILL CONTINUE TO PULSE ACROSS THE GULF OF 
PAPAGAYO OVER THE NEXT 48 HOURS. WINDS WILL PEAK DURING THE LATE 
NIGHT AND EARLY MORNING HOURS...TO FRESH TO LOCALLY STRONG... 
WITH THE ADDED COMPONENT OF NOCTURNAL DRAINAGE FLOW. WINDS WILL 
REACH THE MINIMUM DURING THE AFTERNOON AND EARLY EVENING 
HOURS...WITH MODERATE TO FRESH WINDS PREVAILING. 

MODERATE TO FRESH NORTHERLY WINDS WILL SEEP INTO THE GULF 
OF PANAMA FROM THE SW CARIBBEAN DURING THE NEXT 24 HOURS. THE 
WINDS MAY BRIEFLY AND LOCALLY INCREASE TO STRONG LEVELS DURING 
THE OVERNIGHT HOURS. WINDS OVER THE GULF OF PANAMA WILL DIMINISH 
TUE AND WED AS THE TRADEWINDS IN THE CARIBBEAN DECREASE AND 
WINDS FUNNELING INTO THE GULF OF PANAMA DECREASE. 

LOOKING AHEAD FOR THE GULF OF TEHUANTEPEC...A SURGE OF COLD AIR 
IS FORECAST TO ARRIVE BEHIND A COLD FRONT IN THE GULF OF MEXICO 
WED INTO THU. THE PRESSURE 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 BE FUNNELED THROUGH THE 
CHIVELA PASS ACROSS THE GULF OF TEHUANTEPEC AREA...WITH GALE 
FORCE WINDS POSSIBLE BY LATE WED NIGHT INTO THU. MODEL GUIDANCE 
EVEN HINTS AT THE POTENTIAL FOR MINIMAL STORM FORCE WINDS BY 
LATE THU NIGHT WITH THE WW3 BUILDING RESULTANT SEAS NEAR 20 FT.

$$
AL