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Eastern North Pacific Tropical Weather Discussion

AXPZ20 KNHC 310329

0405 UTC TUE MAY 31 2016

Corrected discussion section to include low near 09N105W

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 0000 UTC surface analysis and satellite imagery through
0230 UTC.


A tropical axis extends from 11N94W to 06N92W moving westward
at 13 kt. Clusters of scattered moderate to isolated strong
convection continue to be quiet active within 180 nm east of the
wave axis. Low pressure may form along the wave as it moves to
near 95W/96W late on Tuesday.

A tropical wave extends from the far southwestern Caribbean Sea 
southeast across central across the Gulf of Panama
and to northwest Colombia. It is moving westward at 10-15 kt. The
wave is helping to produce scattered showers and thunderstorms
over northern Panama and over portions of northwest Colombia.


The monsoon trough axis extends from 14N85W to 10N100W to
09N105W to low pressure near 09N110W 1012 mb to 11.5N115W
to low pressure near 12N118W 1010 mb to 08N129W, then 
transitions to the ITCZ axis from 08N129W to beyond 09N140W.
Scattered moderate to isolated strong convection exists within
180 nm south of the axis between 98W and 108W.


The subtropical ridge prevails over northern waters N of about
15N and west of 115W. A cold front is within about 230 nm to the
northwest of the area. It is being blocked by high pressure
north of the area, and is expected to become stationary west of
140W during the next 36-48 hours. A persistent low pressure area
near 12N119W of 1010 mb is moving southeastward. Latest satellite
imagery shows a cluster of scattered moderate convection within
60 nm of the low in its northeast quadrant. An Ascat pass from 1804Z
Monday showed northerly winds 15 to 20 kt on the northwest periphery
of the low. The low is forecast to reach nears 11N117W by Tuesday
evening, and to near 10N116.5W by Wednesday evening. The same Ascat
pass revealed gentle trade winds over most of the area north of the
convergence zone outside the vicinity of the low, and mainly light
southerly winds to the south. A weak low pressure area is near 09N110W.
This low remains disorganized for the time being. It is forecast
to reach near 09N112W by Tuesday evening, and to near 10N114W by
Wednesday evening. The pressure gradeint is forecast to increase
to the southeast of this low with strong south to southwest
winds developing from 05N to 06N between 109W and 111W late on
Tuesday, and reach westward to near 115W by Wednesday evening
with seas building to the range of 8 to 10 ft. South to
southwest swell moving through much of the south/central and
southeast portions of the area is producing seas of 8 to 9 ft.
This swell is forecast by wavewatch/swell guidance to slowly
dissipate through the next 48 hours, with the seas of 8 to 10 ft
associated with the aforementioned area of strong south to
southwest winds forecast to become the main marine issue at that