067
AXPQ20 PGUM 020112
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1112 AM ChST Fri Oct 2 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...

TROPICAL CYCLONES...
Tropical Storm Choi-wan continues to slowly strengthen, and it has
crossed the northern CNMI passing near Anatahan overnight.
Currently it`s located near 17.0N 144.9E and is moving west-
northwest at 9 mph. Maximum sustained winds remain at 60 mph.
Choi-wan is expected to continue intensifying, possibly becoming a
typhoon tonight. A gradual turn to the north with a slight
decrease in forward speed is expected through Saturday as it
eventually tracks parallel to the Marianas. Maximum estimated seas
near the center is 23 feet. Choi-wan continues to be an
asymmetric system as it fights some northeasterly wind shear, but
this is expected to gradually improve through the weekend, as we
expect the system to become more symmetric. Tropical Storm
Warnings with a Typhoon Watch remain in effect for Agrihan,
Pagan, and Alamagan, with a Tropical Storm Warning also in effect
for Tinian and Saipan.

For more information please refer to bulletins from the Joint
Typhoon Warning Center under WMO header WTPN32 PGTW and from the
National Weather Service under WMO header WTPQ32 PGUM.

TROPICAL AND MONSOON DISTURBANCES...
Much further to the southeast, we have Invest 94W located north of
Kwajalein near 10.0N 167.8E. This is a fairly compact little
circulation, with minimal convection developing near it. Thus far,
despite scatterometer analysis showing a wide swath of 15 to 20
knot winds, no significant wind gusts or heavy rainfall have been
observed with this system at Kwajalein or near Majuro. With that
said, the environment remains conducive for this circulation to
become better defined with time, as the environment is
characterized by low vertical wind shear and warm SSTs (Sea
Surface Temperatures).

...OTHER WEATHER SYSTEMS...

MONSOON TROUGH...
Today the monsoon trough enters the AOR at 13N130 and extends
northeast to Choi-wan near Alamagan in the CNMI. The trough then
extends southeast through a col at 15N160E, continuing southeast
to the Invest 94W where it turns to the east and connects with
another potentially-developing circulation northeast of Majuro. It
then exits the AOR at 10N180. Similar to the past few months,
south of the trough west to southwest winds with cross-equatorial
flow continue. The best moisture and surface convergence remained
confined to the trough and within 200 miles along and to the south
of the trough.

Here PWATs (Precipitable water Values) of 2.5 to 3 inches are
common. The best coverage of convection in the form of numerous to
widespread showers with a few embedded thunderstorms continues to
be located in the southwest monsoon inflow into Choi-wan across
the Marianas, mainly from Guam northward to Anatahan. Widespread
heavy rainfall has been observed here with numerous Flood
Advisories issued from Guam north to Saipan, with a recent Flash
Flood Warning for southern Guam also having been issued.
Incidentally, some river gauges across southern Guam are
reporting all-time record values for this day.

Across the remainder of the monsoon trough, scattered showers with
a few thunderstorms are common, with another local increase in
coverage noted near Kwajalein and Majuro near 94W and the Majuro
potential circulation.

We expect the trough to gradually lift north as Choi-wan and 94W
locally augment its orientation, before it likely settles south
next weekend.

$$

Doll