988
AXPQ20 PGUM 270006
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1006 AM ChST Sun Sep 27 2026

Tropical Weather Discussion for the Western North Pacific between
the Equator and 25N from 130E to 180. The following information is
based on recent satellite imagery/data, weather observations, radar,
and meteorological analysis.

...SPECIAL FEATURES...

None.

...OTHER WEATHER SYSTEMS...

MONSOON TROUGH...
The monsoon trough enters Guam`s AOR at 20N130E and extends
southeast through a col at 18N132E. It then continues to 13N130E,
turning east and passes through Guam to 14N160E, turning east-
southeast to 12N170E, to exit the AOR at 9N180. This position is
about 1 degree further south than yesterday, but, the trough looks
to perhaps be in the stalling process. A low-level circulation
looks to be trying to form just south of the trough near 11.9N
157.2E.

Similar to yesterday, broad southwest to west surface flow is
observed south of the trough axis, with convection stretching
from Koror and Yap east to the RMI, with most convection found
between 7N and 14N. Here scattered showers are common, with the
majority of the thunderstorm activity found near Koror and Yap.
This trough and it`s associated convection looks to remain near
its current position over the next few days, locally augmenting
its orientation with any circulation that forms and moves along
it.

SURFACE TROUGHS...
A surface trough stretches from near Bikini Atoll to just
northwest of Wake Island. This feature denotes a sharp moisture
gradient to its east, as PWATs of 2.5 to 2.8 inches are pulled
northward east of this trough, resulting in widely-scattered
shower development. As discussed yesterday, this northward
moisture pull and its associated convection looks to continue as
it moves west the next few days.

$$

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