000
AXPZ20 KNHC 310925
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU MAR 31 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
0900 UTC.               

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

A SURFACE TROUGH EXTENDS FROM 03N85W TO 04N93W TO 03N103W. THE
ITCZ AXIS IS FROM 03N105W TO 04N119W TO 02N130W TO 02N140W. NO
SIGNIFICANT CONVECTION.

...DISCUSSION...                

A 1022 MB HIGH IS CENTERED N OF THE DISCUSSION AREA NEAR 33N128W
WITH A RIDGE AXIS EXTENDING SE ACROSS THE NORTHERN WATERS TO
NEAR THE REVILLAGIGEDO ISLANDS. THE PRES GRADIENT BETWEEN THE
HIGH AND LOWER PRES IN THE VICINITY OF THE ITCZ IS RESULTING IN
MODERATE TO LOCALLY FRESH TRADES ACROSS THE BASIN W OF 115W.
SCATTEROMETER DATA CONFIRMED THE PRESENCE OF THESE WINDS. SEAS
OF 7-8 FT ARE NOTED PER ALTIMETER DATA WITHIN THE AREA OF THE
TRADES. THE HIGH WILL MOVE SE TO NEAR 31N127W IN ABOUT 24 HOURS
WHILE SLIGHTLY STRENGTHENING.

A COLD FRONT HAS ENTERED THE NW CORNER OF THE FORECAST REGION
AND CURRENTLY EXTENDS FROM 30N138W TO 27N140W. THE FRONT WILL
MOVE SE REACHING A POSITION FROM 30N134W TO 25N140W TONIGHT...
THEN WILL BEGIN TO WEAKEN AND BECOME STATIONARY FROM 30N130W TO
27N132W BY FRI NIGHT. THE MOST RECENT ALTIMETER PASS INDICATED
SEAS TO NEAR 11 FT IN THE WAKE OF THE FRONT. LONG PERIOD NW
SWELL ASSOCIATED WITH THIS SYSTEM WILL CONTINUE TO PROPAGATE
ACROSS THE FORECAST WATERS OVER THE NEXT COUPLE OF DAYS COVERING
THE AREA W OF A LINE FROM 30N127W TO 20N130W TO 07N140W BY
TONIGHT. EXPECT BUILDING SEAS TO 12-13 FT NEAR 30N140W LATER
TODAY.

NIGHT CHANNEL VISIBLE IMAGERY SUGGESTS THE PRESENCE OF A BROAD
TROUGH WITHIN THE ITCZ ALONG 120W S OF 09N. THE CLOUD FIELD
SHOWS SOME INVERTED-V PATTERN. THE PRESSURE GRADIENT BETWEEN THE
RIDGE TO THE N AND THE TROUGH WILL TIGHTEN...ALLOWING FOR TRADES
NW OF THE TROUGH TO INCREASE TO FRESH LEVELS. SEAS WILL BUILD TO
8-9 FT IN THE AREA OF FRESH TRADES...EVENTUALLY MERGING WITH THE
ONCOMING NW SWELL ON FRI.

CROSS EQUATORIAL SW SWELL WILL CONTINUE TO PROPAGATE ACROSS THE
S-CENTRAL WATERS TONIGHT...SUBSIDING TO LESS THAN 8 FT N OF THE
EQUATOR BY 12 HOURS.

A LOCALLY TIGHT PRESSURE GRADIENT IS EXPECTED TO DEVELOP IN THE
PACIFIC WATERS OFF THE COAST OF SOUTHERN BAJA CALIFORNIA BY
EARLY TODAY. IN FACT...LATEST SCATTEROMETER DATA SHOWED A SMALL
AREA OF NW WINDS IN THE 20-25 KT RANGE FROM 22N TO 23N BETWEEN
109W TO 111W. FRESH TO STRONG NW WINDS WILL CONTINUE TO FUNNEL
ALONG THE SOUTHERN TIP OF THE BAJA PENINSULA THROUGH LATE TODAY.
SEAS ARE EXPECTED TO BUILD TO 8-9 FT IN THIS AREA IN MIXED NW
WIND WAVES AND SW SWELL.

LOOKING AHEAD...

IN THE GULF OF TEHUANTEPEC...THE FIRST GALE-FORCE GAP WIND EVENT
OF A SEASON TYPICALLY OCCURS IN MID-OCTOBER...WITH THE FINAL
GALE FORCE EVENT OCCURRING IN LATE MARCH OR EARLY APRIL. THE NEXT
GULF OF TEHUANTEPEC GALE FORCE WIND EVENT IS EXPECTED ON SAT.
WINDS ARE FORECAST TO INCREASE FROM 15-20 KT AROUND 1800 UTC SAT
TO 30-35 KT BY 0000 UTC SUN...THEN WINDS WILL FURTHER INCREASE
TO 35-40 KT BY 0600 UTC SUN. SEAS ARE EXPECTED TO BUILD TO 13-14
FT WITH THESE WINDS. IT IS POSSIBLE THAT THIS EVENT MAY BE THE
LAST ONE OF THE 2015-2016 SEASON. 
  
$$
GR