918
AXPQ20 PGUM 050019
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1019 AM ChST Fri Sep 5 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...

TRADE-WIND TROUGHS...
There are several trade-wind troughs seen across the region this
morning. The first trough is seen to the east of Yap Proper, and to
west of Rota. It extends north-northeast from near 6N140E to end
near 15N143E. Scattered showers and isolated thunderstorms are found
with the trough from near Ngulu, across Yap Proper to west of Rota.
The trough will continue to move west over the coming days, passing
near Koror, Palau, with little change in intensity.

The next trade-wind trough is found east of the Marianas, extending
north from near 10N150E to end near 18N151E. This trough is
interacting with divergence associated with the TUTT to produce
scattered to numerous showers across the Marianas eastward to the
just west of the trough axis. To the east of the axis, a band of
convergence is also interacting with divergence associated with the
TUTT to produce numerous showers and isolated thunderstorms well east
of the Marianas. This trough will continue westward as it slowly
strengthens due to continued interaction with the TUTT.

The next trough is seen to the east through south of Weno, Chuuk,
extending north-northeast from near 1N151E to end near 7N153E.
Convergence associated with this trough is generating scattered to
numerous showers and isolated thunderstorms south to southwest of
Weno, with the convergence band extending as far west as 144E, south
of 4N. This trough will continue west as it weakens slightly.

The fourth trough is seen near Pohnpei, extending north-northeast
from 2N157E to end near 13N162E. Scattered showers and isolated
thunderstorms are associated with this trough. This trough looks to
move west over the coming days as it slowly strengthens.

The last, weak, trade-wind trough is found well north of Majuro,
extending north-northeast from near 12N173E to end near 18N178E.
Scattered showers and isolated thunderstorms are found with the
trough. This trough looks to move west-northwest over the next few
days with little change in intensity.

TUTT...
The TUTT enters the region near 22N180, extending west-southwest to
a TUTT cell centered west of Wake Island near 20N160E. It continues
west-southwest through another, very weak, cell centered near
18N149E, turning more west to beyond 130E near 18N. Divergence
associated with the TUTT is interacting with a trade-wind trough east
of the Marianas to produce scattered to numerous showers and isolated
thunderstorms over and east of the Marianas, and again well east of
the Marianas, to the east of the trade-wind trough.

Divergence associated with the TUTT is also interacting with a west
to east oriented surface trough well west of the northern CNMI to
produce scattered to numerous showers and isolated thunderstorms
south of the surface trough. The TUTT looks to remain quasi-
stationary as the cells slowly drift west over the coming days. The
TUTT is expected to show little change in strength.

OTHER SYSTEMS...
A west to east oriented surface trough is seen well west of the
northern CNMI, extending across 130E near 19N to end near 19N136E.
Convergence south of the trough is interacting with divergence
associated with the TUTT to generate scattered to numerous showers
and isolated thunderstorms south of the trough. The trough looks to
slowly drift northwest over the coming days as it gradually
intensifies.

...ITCZ...
Only a small fragment of the ITCZ remains, located to the north of
Majuro from near 9N171E to end near 9N177E. A band of scattered
showers and isolated thunderstorms are found along the ITCZ
fragment. This fragment will continue to weaken over the next day or
so and is not expected to be a major player in the weather across
the region.

$$

Kleeschulte