000
AXPZ20 KNHC 011005
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI APR 01 2016

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0930 UTC.               

...SPECIAL FEATURES...

GULF OF TEHUANTEPEC GALE WARNING...THE NEXT GALE FORCE WIND
EVENT IS FORECAST TO DEVELOP EARLY ON SAT EVENING. A COLD FRONT
WILL SWEEP ACROSS THE WESTERN GULF OF MEXICO ON SAT AND SAT
EVENING FOLLOWED BY HIGH PRES THAT BUILDS SWD ALONG THE SIERRA
MADRE ORIENTAL MOUNTAINS OF MEXICO. THIS WILL BRING A TIGHT PRES
GRADIENT OVER SOUTHEASTERN MEXICO THAT WILL ALLOW FOR STRONG TO
GALE FORCE NLY WINDS CONSISTING OF COOL AIR TO FUNNEL THROUGH
THE NARROW CHIVELA PASS...AND OUT INTO THE GULF OF TEHUANTEPEC
WHERE WARM (28.5-29 DEG CELSIUS) SEA SURFACE TEMPERATURES ARE
PRESENT. MINIMAL GALE FORCE WINDS WILL GRADUALLY INCREASE TO
NEAR OR TO 40 KT BY LATE SAT NIGHT AND INTO SUN MORNING WITH THE
AIDED BY THE ASSISTANCE OF NOCTURNAL DRAINAGE. THESE WINDS WILL
THEN DIMINISH SLIGHTLY ON SUN AFTERNOON. SEAS WILL BUILD TO 12
FT SAT EVENING...AND TO AROUND 14 FT BY LATE SAT NIGHT...AND
POSSIBLY TO 17 FT ON SUN PER A MODEL BLEND OF TAFB NWPS
PARAMETERS AND THE 00 UTC MWW3 WAVE GUIDANCE.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 
      
ITCZ AXIS EXTENDS FROM 05N91W TO 04N100W TO 04N110W TO 05N116W
TO 06N122W WHERE IT IS DISSECTED BY A WEAK SURFACE TROUGH
ALONG 124W FROM 01N-09N. THE ITCZ AXIS RESUMES AT 03N126W TO THE
EQUATOR AT 140W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM S
OF THE AXIS BETWEEN 95W-102W...AND ALSO WITHIN 30 NM S OF THE
AXIS BETWEEN 120W-121W. 

...DISCUSSION... 

WATER VAPOR IMAGERY SHOWS MAINLY MODERATE TO STRONG SUBSIDENCE WITH 
DRY CONDITIONS OVER JUST ABOUT THE ENTIRE DISCUSSION AREA EXCEPT
FOR THE FAR NW PORTION AND FAR S CENTRAL PORTION IN THE TROPICAL
ZONE BETWEEN 102W-119W...WHICH IS IN BETWEEN A LARGE UPPER
ANTICYCLONE CENTERED NEAR 09N92W AND A BROAD UPPER TROUGH THAT
COVERS THE CENTRAL SECTION OF THE AREA.

AT THE SURFACE... A 1025 MB HIGH IS CENTERED NEAR 32N127W WITH A
RIDGE AXIS EXTENDING SW TO BEYOND 22N140W. ANOTHER RIDGE EXTENDS
FROM THE HIGH SEWD TO NEAR 16N105W. HIGH PRES COVERS THE AREA N
OF 14N W OF 105W. THE PRES GRADIENT BETWEEN THE HIGH AND LOWER
PRES IN THE VICINITY OF THE ITCZ IS RESULTING IN MODERATE TO
FRESH TRADES ACROSS AN AREA GENERALLY FROM ABOUT 05N TO 19N W OF
116W WITH SEAS IN THE 6-8 FT RANGE DUE TO A SE-S SWELL. THE HIGH
IS FORECAST TO REMAIN NEARLY STATIONARY THROUGH LATE SAT NIGHT.

A WEAKENING FRONTAL TROUGH ENTERS THE AREA THROUGH 32N133W...
AND CONTINUES SW TO 27N136W TO 25N140W. THE TROUGH WILL CONTINUE
TO WEAKEN AS IT REACHES FROM NEAR 32N129W TO 26N134W AND
STATIONARY TO 24N140W BY LATE TONIGHT...FROM NEAR 32N128W TO 
26N134W AND STATIONARY TO 24N140W SAT MORNING THEN DISSIPATE BY
LATE SAT NIGHT. THE MAIN ISSUE OVER MUCH OF THE FORECAST REGION
WILL BE A LARGE AREA OF NW SWELL WITH 8-12 FT SEAS. PRESENTLY
THE SWELL IS W OF A LINE FROM 32N127W TO 20N132 TO 10N140W WITH
THE SEAS OF 10-12 FT CONFINED TO N OF 28N W OF 136W. THE NW
SWELL IS FORECAST TO BE W OF A LINE FROM 32N117W TO 19N121W TO
09N119W TO 03N140W IN 24 HOURS...BUT WITH SEAS SLOWLY SUBSIDING
TO 8-10 FT. BY LATE SAT NIGHT...THE SEAS ARE EXPECTED TO BE 8-9
FT IN THE NW SWELL WITHIN AN AREA BOUNDED BY 29N121W TO 20N116W
TO 14N118W TO 04N126W TO 08N140W TO 29N121W.

SHORTWAVE IR SATELLITE IMAGERY INDICATES A BROAD AND WEAK
SURFACE TROUGH EMBEDDED WITHIN THE ITCZ ROUGHLY ALONG 124W FROM
01N-09N MOVING W 15-20 KT. THE PRES GRADIENT BETWEEN THE RIDGE
TO THE N AND THE TROUGH WILL TIGHTEN SLIGHTLY DURING THE NEXT 24
TO 30 HOURS ALLOWING FOR NE TRADES TO INCREASE TO 20-25 KT FROM
07N-09N BETWEEN THE TROUGH ALONG POSITION FROM 09N128W TO
01N129W AND 136W WITH ASSOCIATED SEAS OF 9-10 FT. BY LATE SAT
NIGHT...THE TROUGH IS FORECAST TO REMAIN WEAK ALONG A POSITION
FROM 08N135W TO 01N137W WITH NE TRADES NEAR IT AT MOSTLY 20 KT
...AND WITH SEAS OF 9-10 FT IN NW SWELL FROM 04N-08N E OF THE TROUGH
TO 126W...AND FROM 03N-08N W OF THE TROUGH TO 140W.

$$
AGUIRRE