965
AXPQ20 PGUM 220046
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1046 AM ChST Tue Jul 22 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...

TROPICAL AND MONSOON DISTURBANCES...
The tropical disturbance known as JTWC`s Invest 97W is located near
15.6N, 133.1E. Although slow to develop, Invest 97W has become better
organized over the last few hours with a low to mid level
circulation present with convection increasing around it. The JTWC
currently rates Invest 97W as medium, which means that TC development
is likely, but expected to occur beyond 24 hours. Invest 97W looks
to remain in our Area of Responsibility (AoR) for the next day or two
as it moves northwest out of our region.

The tropical disturbance known as JTWC`s Invest 98W is located near
8.1N, 152.2E. Currently, little to no convection is seen near the
weak circulation at these coordinates. There is quite a bit of
convection just to the north near 10N152E. This is where the
hurricane models show Invest 98W start to consolidate. JTWC currently
rates Invest 98W as a low. This means that development into a
tropical cyclone is not expected over the next 24 hours. Invest 98W
is forecasted to move west-northwestward before turning northward
near the Marianas. Very heavy rainfall will be possible across the
Marianas late in the week in association with Invest 98W.

...OTHER WEATHER SYSTEMS...

MONSOON TROUGH...
The monsoon trough enters the region near 16N130E and extends
eastward into Invest 97W. From there, the monsoon trough continues
east-southeastward to 14N140E and then dives southeast to 7N146E.
Numerous showers are seen across the monsoon trough along the low-
level convergence region. The monsoon trough is expected to lift
northward over the coming days as Invest 97W lifts northwest of the
region.

TRADE-WIND TROUGHS...
There are a few trade-wind troughs across the region. The first is
located west of the Marianas, stretching from 15N138E to 22N145E.
Scattered to numerous showers and isolated thunderstorms are seen
along this trough where it`s interacting with both an upper level
trough and the monsoon trough.

The second trade-wind trough was located just west of the RMI and
extends from 5N160E to 14N168E. This trough is interacting to produce
scattered showers across the RMI and numerous showers north of
Kwajalein.

The final trough is seen east of the RMI located from 7N174E to
15N179E. Numerous showers are seen where the trade-wind trough and
the ITCZ interact. All three troughs will generally move westward
over the coming days with little change in intensity.

TUTT...
A weakening TUTT and TUTT cell are found well north of the Marianas
near 25N145E. The TUTT was cut off by an upper level anticyclone near
20N150E. The TUTT then continues eastward from 25N147E to 22N180.
Some scattered showers and isolated thunderstorms are located along
the TUTT cell north of the Marianas. Both features of the TUTT look
to weaken as they shift westward over the coming days.

...ITCZ...
The ITCZ enters the region around 6N180 and extends westward into
the northern RMI to about 11N170E and then shifts southwest to
6N165E. The ITCZ is in an active phase with trade-wind troughs
bisecting portions of the ITCZ. Numerous to widespread showers are
seen north of Kwajalein where the ITCZ is converging with the trade
winds. There is little change in intensity expected over the next day
or two before the ITCZ begins to fragment in the latter half of the
week.

$$

Williams