000
AXPZ20 KNHC 291530
TWDEP 

TROPICAL WEATHER DISCUSSION                                     
NWS NATIONAL HURRICANE CENTER MIAMI FL                          
1605 UTC FRI NOV 29 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 
1400 UTC.

...SPECIAL FEATURES...

A GALE WARNING REMAINS IN EFFECT FOR THE GULF OF TEHUANTEPEC. 
THERE HAVE BEEN FEW SHIP OR SCATTEROMETER WIND OBSERVATIONS TO 
CONFIRM THESE CONDITIONS...BUT AN 0900 UTC JASON-2 ALTIMETER 
PASS SHOWED SEAS AS HIGH AS 14 FT WITH A SIZABLE AREA OF SEAS 
OVER 8 FT S OF THE GULF. THIS PASS WAS W OF THE AREA OF HIGHEST 
EXPECTED SEAS. WINDS ARE EXPECTED TO REMAIN AT GALE FORCE 
THROUGH THE END OF THE FORECAST PERIOD ON SUN MORNING AND 
DIMINISH AFTER THE PEAK DIURNAL DRAINAGE FLOW DISSIPATES ON SUN. 

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

THE MONSOON TROUGH AXIS EXTENDS FROM 07N77W TO 08N84W TO 06N90W 
THEN ITCZ TO 10N128W TO 08N140W. SCATTERED MODERATE WITH 
ISOLATED STRONG CONVECTION LIES WITHIN 90 NM EITHER SIDE OF THE 
AXIS BETWEEN 90W AND 96W AS WELL AS WITHIN 150 NM N OF THE AXIS 
BETWEEN 104W AND 111W. SCATTERED MODERATE CONVECTION LIES WITHIN 
90 NM S OF THE AXIS BETWEEN 118W AND 128W AS WELL AS WITHIN 270 
NM N OF THE AXIS BETWEEN 119W AND 124W.

...DISCUSSION...

A WEAKENING COLD FRONT STEMS FROM 1004 MB OCCLUDED LOW PRES 
SYSTEM NEAR 32N127W AND ENTERS THE FORECAST AREA AT 30N118W THEN 
PASSES THROUGH 26N120W TO 19N140W. WINDS NEAR THE FRONT HAVE 
DIMINISHED BELOW A STRONG BREEZE...BUT NW SWELL CONTINUES TO 
SUPPORT SEAS TO 12 FEET THIS MORNING. SWELL OVER 8 FT FROM THIS 
SYSTEM HAS REACHED THE NORTHERN PORTION OF THE BAJA CALIFORNIA 
PENINSULA AND STRETCHES AS FAR S AS 08N IN WESTERN WATERS. THE 
FRONT WILL DISSIPATE STARTING LATER TODAY. THE LOW PRES SYSTEM 
IS FORECAST TO SINK S AND WEAKEN...OPENING UP TO A TROUGH BY SAT 
MORNING. THE PRES GRADIENT WILL TIGHTEN OVER THE NW WATERS 
BETWEEN THE TROUGH AND BUILDING HIGH PRES NW OF THE AREA 
RESULTING IN FRESH TO STRONG NE WINDS IN THE NW CORNER OVER THE 
WEEKEND.

A PAIR OF SURFACE TROUGHS ARE EMBEDDED IN THE ITCZ. THE EASTERN 
TROUGH EXTENDS FROM 18N120W TO 08N127W. SCATTERED MODERATE 
CONVECTION LIES ON THE N SIDE OF THE TROUGH FROM 18N TO 23N 
BETWEEN 116W AND 123W AS WELL AS WITHIN 90 NM S OF THE ITCZ 
BETWEEN 118W AND 128W NEAR THE TROUGH. THE WESTERN TROUGH 
EXTENDS FROM 14N130W TO 08N135W. THE WESTERN TROUGH IS FORECAST 
TO DISSIPATE WHILE THE ENERGY SUPPORTING THE EASTERN TROUGH WILL 
JOG NORTHWARD ONTO THE LEADING EDGE OF THE UPPER TROUGH 
ASSOCIATED WITH THE COLD FRONT N OF THE AREA. THE UPPER JET ON 
THE LEADING EDGE OF THIS UPPER TROUGH WILL INTENSIFY OVER THE 
WEEKEND...PROMOTING UPPER DIFFLUENCE AND LIFT AT THE SURFACE 
NEAR THE TROUGH. EXPECT THE SURFACE TROUGH...WHICH WILL LIE 
UNDER THE REAR RIGHT QUADRANT OF THE JET...TO BECOME A FOCUS FOR 
CONVECTION. 

GAP WINDS...FRESH TO STRONG NE WINDS ARE SURGING THROUGH THE 
GULFS OF PAPAGAYO AND FONSECA THIS MORNING. THE 0338 UTC ASCAT 
PASS SHOWED PEAK WINDS AROUND 30 KT JUST S OF THE GULF OF 
FONSECA. THIS SURGE OF NORTHERLY FLOW SHOULD BE DIMINISHING... 
BUT MAXIMUM NOCTURNAL DRAINAGE FLOW LIKELY ALLOWED WINDS TO 
REMAIN AT 30 KT THIS MORNING IN THE REGION. THE PRESSURE 
GRADIENT BETWEEN RIDGING TO THE N AND THE MONSOON TROUGH TO THE 
S SHOULD WEAKEN TODAY. STRONG NE WINDS SHOULD BE CONFINED TO THE 
GULF OF PAPAGAYO BY LATER TODAY AND WILL SHRINK IN AREA THROUGH 
SUN MORNING.
 
$$
SCHAUER