915
AXPQ20 PGUM 110118
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1118 AM ChST Fri Sep 11 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 our Area of Responsibility (AOR) around
14N130E and extends southeast through a broad circulation near
9N144E, just east of Gaferut, Yap State. High-end scattered to
numerous showers and deepening convection is approaching Yap Island
and Sorol from the north. The trough continues west-northwest,
intersecting another circulation near 14N163E before continuing
southeast through another circulation around 7N175E and exiting
across the Date Line around 7N. Most of the unsettled weather is
affecting much of eastern Micronesia, with high-end scattered to
numerous showers and isolated thunderstorms at or around Weno,
Chuuk, Pohnpei, Kosrae, and Majuro. The monsoon trough will
generally remain unchanged in intensity and quasi-stationary over
the next day or so.

A monsoon surge is located from the Equator around 144E to the
northeast ending north of Pohnpei around 10N158E. An area of
numerous showers and isolated thunderstorms are observed affecting
portions of Pohnpei and Chuuk States. This surge and unsettled
conditions are expected to remain generally stationary over the next
day or so.

SURFACE TROUGHS...
A surface trough extends from one of the aforementioned circulations
east of Majuro south to the Equator around 175E. Scattered showers
and multiple outflow boundaries are affecting Makin and Marakei of
the Republic of Marshall Islands (RMI), partly due to a convergence
zone also associated with the circulation and surface trough
interaction. This trough will gradually move north following the
parent circulation while decreasing in intensity over the next few
days.

TRADE-WIND TROUGHS...
A trade-wind trough extends from one of the embedded monsoon
circulations near 14N163E north ending around 19N161E. Towering
convection and scattered showers are over open waters well northwest
of Wake Island. This trough is also interacting with an upper-level
low discussed below, so the trough will continue moving west
unchanged in intensity for the next few days.

OTHER SYSTEMS...
An upper-level low is centered near 22N156E, with quite an expansive
rotation of winds. Most of the unsettled weather is located along
its southern peripheries characterized by scattered convection and
numerous showers. This feature is also causing isolated
thunderstorms and towering cumulonimbus from the typical trade wind
cumulus clouds. With that being said, no islands are being affected
by this pattern as of right now. This feature is expected to continue
moving west, passing well north of the Marianas, through the weekend
remaining unchanged in intensity.

$$

Mesa