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Eastern North Pacific Tropical Weather Discussion

AXPZ20 KNHC 311520

1605 UTC TUE MAY 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 1200 UTC surface analysis and satellite imagery through
1500 UTC.


Tropical wave is along 12N92W 09N94W 05N95W. Convective
precipitation: scattered to numerous strong from 05N to 08N
between 93W and 97W. Scattered moderate to isolated strong from
04N to 08N between 91W and 93W.


The monsoon trough extends from 12N86W to 12N93W to low pres
near 09N110W to low pres near 10N115W to 07N121W. ITCZ extends
from 07N121W to beyond 07N140W. Scattered moderate isolated
strong convection from 06N to 11N between 92W and 108W. 


A cold front about 180 nm west of 140W extends from a 1012 mb
low near 32N143W to 26N143W. The front is being blocked by a N-S
oriented surface ridge along 133W extending south from 1022 mb
high near 38N133W. The front will become stationary during the
next 12-24 hours, and model guidance shows the front undergoing
a complex transition to a trough then into a surface low north
of 24N west of 140W through Wed. A broad subtropical ridge is
expected to prevail over northern waters west of 113W through
Thu. An elongated low pressure trough is analyzed along 9N-10N
between 95W and 120W, with a pair of weak low centers identified
near 09N110W and 10N115W. Satellite imagery shows broad cyclonic
turning all along the trough axis but no clearly organized lows.
Model consensus indicates a tropical low will develop out of the
broad trough in 2-3 days, when environmental conditions will be
more favorable for it to intensify into a tropical depression
after breaking free of the convergence zone. In the interim,
expect monsoonal W-SW flow south of the trough axis to gradually
strengthen, which will allow seas to build to 8-9 ft in a broad
area straddling 10N between 95W-120W through Thu afternoon.