845
AXPQ20 PGUM 290118
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1118 AM ChST Fri Aug 29 2025

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 the WFO Guam Area of Responsibility near
11N130E, heads east-southeastward between Koror and Yap to a weak
circulation near 8N144E then turns southeastward to end near EQ152E.
Numerous showers and isolated thunderstorms are observed mainly south
of Koror and Yap. The monsoon trough is expected to intensify over the
weekend, mainly by lifting northward and expanding eastward.

A monsoon-like disturbance is centered near Chuuk Lagoon around
7N152E. Scattered showers and isolated thunderstorms are seen between
3N and 15N from 144E to 157E, including the Marianas from Saipan
southward, far eastern Yap State, and Chuuk State. This disturbance
is expected to intensify over the weekend by linking up with the
monsoon trough.

TRADE-WIND TROUGHS...
A trade-wind trough north of Majuro and Kwajalein runs from 10N171E to
near Wake Island at 18N168E to 25N170E and farther north-northeast.
Scattered showers and isolated thunderstorms are noted between 12N and
15N from 166E to 170E. This trough is expected to move westward with
little change of intensity.

Another trade-wind trough stretches from 14N130E to 25N138E. Scattered
showers and isolated thunderstorms are found between 21N and 25N from
132E to 139E, or well north of Palau and Yap. This trough is also
forecast to move westward with little change of intensity.

TUTT...
The Tropical Upper Tropospheric Trough (TUTT) curves from 25N152E to
upper-level lows near 24N157E and 23N166E then continues to near
25N180. Scattered showers and isolated thunderstorms are found between
the Commonwealth of the Northern Marianas and Wake Island from 15N to
25N between 150E and 164E. The TUTT is expected to show little change
in either location or intensity through the weekend.

...ITCZ...
An Inter-Tropical Convergence Zone is located north and east of
Majuro, roughly from 10N170E to 8N180. Low-level convergence
associated with the ITCZ is creating scattered showers and a few
thunderstorms between 4N and 11N from 170E to 180 and farther east.
The ITCZ is forecast to show little change in either location or
intensity through the weekend.

$$

Stanko