000
AXPZ20 KNHC 201618
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL 
1605 UTC THU DEC 19 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... 

MONSOON TROUGH AXIS EXTENDS FROM LOW PRES NEAR 07N79W TO 10N86W 
TO 05.5N100W... WHERE IT TRANSITIONS TO THE ITCZ...CONTINUING ON 
TO 08.5N114W TO 07N123W TO 10N130W TO 08N140W. 

SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 90 NM 
N OF AXIS BETWEEN 92W AND 115W. SCATTERED MODERATE TO STRONG 
CONVECTION NOTED WITHIN 310 NM N OF ITCZ BETWEEN 123W AND 130W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 90 NM 
OF ITCZ W OF 133W. 

...DISCUSSION... 

A FAST MOVING COLD FRONT CONTINUES TO PUSH S AND SE ACROSS N 
PORTIONS AND NORTHERN BAJA CALIFORNIA...AND EXTENDS FROM A 1002 
MB LOW NEAR 33N112W TO 24N120W TO 26.5N140W. NW TO N WINDS 20-25 
KT PREVAIL BEHIND THE FRONT...WHERE SEAS ARE UP TO 16 FT ALONG 
30N. NORTHERLY WINDS TO NEAR 30 KT THAT WERE OCCURRING OVERNIGHT 
N OF 29N HAVE DIMINISHING TO 25 KT THIS MORNING. STRONG 1038 MB 
HIGH PRES NEAR 39N142W CONTINUES TO DRIVE THESE FRESH TO STRONG 
NORTHERLY WINDS BEHIND THE FRONT...AND WILL FORCE IT S AND SE TO 
S PORTIONS OF BAJA TO NEAR 20N125W WITHIN 48 HOURS. MEANWHILE... 
THE NW TO N WINDS BEHIND THE FRONT WILL GRADUALLY DIMINISH 
THROUGH SAT AS THE PRES GRADIENT WEAKENS. LARGE NLY SWELLS 
BEHIND THE FRONT WILL SLOWLY SUBSIDE TO 10-12 FT TONIGHT...AND 
TO 8-11 FT BY SAT NIGHT. 

A STRONG SURFACE RIDGE EXTENDS INTO THE AREA FROM THE ABOVE 
MENTIONED 1038 MB HIGH PRES. THE PRES GRADIENT BETWEEN THE HIGH 
AND LOWER PRESSURE ALONG THE ITCZ IS PRODUCING FRESH TO STRONG 
TRADE WINDS BETWEEN THE RIDGE AND ITCZ...FROM 10N TO THE FRONT 
AND W OF 131W. THE PRES GRADIENT WILL GRADUALLY RELAX THROUGH 
SAT NIGHT AS HIGH PRES MOVES S AND WEAKENS.

VERY LONG PERIOD NW SWELLS...WITH WAVE PERIODS BETWEEN 20-22 
SEC...WILL BEGIN TO MOVE INTO THE WATERS OF THE FAR NW CORNER 
TODAY...AND WILL PROPAGATE ACROSS THE NW WATERS ON SAT... 
REACHING THE REMAINDER OF THE WESTERN PART OF THE FORECAST AREA 
SAT NIGHT. THIS SWELL WILL GRADUALLY BUILD AS IT PROPAGATES SE 
ACROSS THE AREA AND MIX WITH THE DYING NORTHERLY SWELL GENERATED 
BEHIND THE CURRENT COLD FRONT. 

GULF OF TEHUANTEPEC...THE RECENT LONG DURATION GALE EVENT ACROSS 
THE GULF OF TEHUANTEPEC ENDED. RECENT SCATTEROMETER DATA ONLY 
SHOW NORTHERLY WINDS OF 10-15 KT ACROSS THIS AREA. THE NEXT GAP 
WIND EVENT IS FORECAST TO BEGIN LATE SUN NIGHT INTO MON WITH 
WINDS REACHING GALE FORCE AGAIN. THIS NEXT EVENT WILL LIKELY BE 
ANOTHER STRONG ONE AS MARINE GUIDANCE INDICATES THAT IT WILL 
PERSIST THROUGH THE MIDDLE OF NEXT WEEK.

GULF OF PAPAGAYO...NE-E GAP WINDS WILL CONTINUE TO BLOW 
DOWNSTREAM OF PAPAGAYO OVER THE NEXT 48 HOURS. WINDS THERE HAD 
PULSED TO 20-25 KT OVERNIGHT AND THIS MORNING AND WILL DIMINISH 
DURING EACH OF THE NEXT FEW AFTERNOONS TO 15-20 KT. 

GULF OF CALIFORNIA...AN OVERNIGHT ASCAT PASS SHOWED SW WINDS OF 
20-25 KT OVER THE EXTREME NRN PORTION OF THE GULF AHEAD OF THE 
AFOREMENTIONED COLD FRONT. THESE WINDS WILL BEGIN TO DIMINISH 
TODAY AS THE FRONT WEAKENS AND MOVES SE. HIGH PRES WILL BUILD 
BACK INTO THE REGION THIS WEEKEND FROM THE NW...AND INCREASE THE 
PRES GRADIENT TO SUPPORT NW WINDS OF 15-20 KT ACROSS THE ENTIRE 
GULF OF CALIFORNIA ON SUN EVENING.
 
$$
STRIPLING