000
AXPZ20 KNHC 021605
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                      
1605 UTC WED MAR 02 2015 

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 1500 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1545 UTC.               
  
...SPECIAL FEATURE...

GULF OF TEHUANTEPEC GALE WARNING...A NORTH-SOUTH PRESSURE
GRADIENT FROM THE SOUTHWESTERN GULF OF MEXICO ACROSS SOUTHERN
MEXICO IS INDUCING A STRONG BREEZE TO NEAR GALE GAP WIND EVENT
CURRENTLY OVER THE GULF OF TEHUANTEPEC.  THE FORCING IS GOING TO
WEAKEN DURING THE DAY DUE TO DIURNAL VARIABILITY...BUT
RESTRENGTHEN TONIGHT. CURRENTLY OUR FORECAST IS INDICATING A
SHORT-LIVED...6 HOUR...GALE AROUND 06Z THIS EVENING THOUGH THE
FORCING IS NOT VERY STRONG. MOREOVER...RECENT MODEL GUIDANCE HAS
BEEN BACKING OFF OF A GALE SOLUTION WITH THE 00Z ECMWF HIGH
RESOLUTION AND ENSEMBLE MEAN SHOWING A PEAK OF ONLY 25 KT...THE
06Z GFS HIGH RESOLUTION AND ENSEMBLE MEAN SHOWING A PEAK OF 25-
30 KT...WITH A NEAR ZERO CHANCE OF GALE PROBABILITIES FROM THE
GFS ENSEMBLES...AND THE 00Z UKMET ALSO SHOWING A PEAK OF 25 KT.
IF THE 12Z GFS LIKEWISE INDICATES SUB-GALE CONDITIONS...THEN THE
NEXT HIGH SEAS FORECAST WILL JETTISON THE GALE WARNING.  ANOTHER
STRONG SURGE TO NEAR GALE CONDITIONS IS EXPECTED TO OCCUR ON
FRIDAY NIGHT TO SATURDAY.    

...INTERTROPICAL CONVERGENCE ZONE...

A SURFACE TROUGH EXTENDS FROM 10N86W TO 05N90W. ITCZ EXTENDS
FROM 05N90W TO 04N110W TO 02N140W. ISOLATED MODERATE CONVECTION
EXISTS WITHIN 120 NM N OF AXIS FROM 90W TO 105W AND W OF 130W.

...DISCUSSION...
 
A COLD FRONT HAS ENTERED OUR NW CORNER...EXTENDING FROM 30N138W
TO 28N140W.  ASCAT SCATTEROMETER WINDS AT 06 AND 07Z OVERNIGHT
SHOWED STRONG BREEZE TO NEAR GALE SW WINDS AHEAD OF THE FRONT
AND THE SAME MAGNITUDE NW WINDS BEHIND THE FRONT.  THE FORCING
FOR THIS FRONT...HOWEVER...IS QUICKLY MOVING NORTHEASTWARD AND
WINDS BOTH AHEAD AND BEHIND THE FRONT ARE EXPECTED TO WEAKEN
QUICKLY.  IN ABOUT 12 HOURS...WINDS IN OUR AREA SHOULD DROP TO
FRESH BREEZE CONDITIONS.  DESPITE THE WINDS WEAKENING...A LARGE
NW SWELL ASSOCIATED WITH THE STORM-FORCE CYCLONE THAT THE FRONT
IS ATTACHED TO IS MOVING INTO OUR AREA.  A NEW ALTIMETER PASS AT
11Z SHOWS THAT 14 FT SEAS ARE JUST REACHING THE NW CORNER AT
30N140W.  THESE WILL PEAK IN AT AROUND 19 FT TONIGHT AND SLOWLY
FADE DURING THE NEXT COUPLE OF DAYS.  THIS FORECAST IS SHOWN
BOTH IN THE GFS-BASED WAVE WATCH III MODEL AND IS A NEAR
CERTAINTY FROM THE ENSEMBLE PROBABILITIES.  SEAS OF AT LEAST 12
FT WILL COVER A LARGE AREA WEST OF LINE FROM 30N122W TO 18N140W
BY FRIDAY MORNING.  THE NEXT SIGNIFICANT FRONT WILL BE REACHING
OUR 30N BORDER SATURDAY AND IMPART STRONG BREEZE TO NEAR GALE
CONDITIONS. THIS SYSTEM...LIKE THE CURRENT ONE...MAY ALSO PUSH
NORTHEASTWARD WITHOUT ALLOWING ANY GALES IN OUR AREA.

A 1023 MB HIGH PRESSURE IS CENTERED AT 32N124W.  THE
NORTHEASTERLY TRADEWINDS EQUATORWARD OF THE HIGH ARE ONLY
MODERATE TO FRESH BREEZE CONDITIONS.  THE WIND WAVES FROM THESE
COMBINED WITH A PRE-EXISTING NW SWELL ARE PRODUCING SEAS UP TO 8
FT WEST OF 100W SOUTH OF 12N.  THE AREAL COVERAGE OF THESE WILL
SHRINK DURING THE NEXT COUPLE OF DAYS.

ELSEWHERE S OF 15N E OF 110W...NOCTURNAL PULSES OF STRONG BREEZE
ENE WINDS WILL CONTINUE ACROSS...AND DOWNSTREAM OF THE GULF OF
PAPAGAYO THROUGH FRIDAY NIGHT.  SEAS SHOULD REMAIN LESS THAN 8
FT DUE TO LIMITED FETCH AND DURATION OF THESE WINDS.

$$
LANDSEA