956
AXPQ20 PGUM 290148
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1148 AM ChST Tue Sep 29 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 AND MONSOON DISTURBANCES...
A developing disturbance found along the monsoon trough, Invest 93W,
is centered E of Saipan near 15.2N 155.5E. 93W is now rated medium
by the Joint Typhoon Warning Center (JTWC), meaning that development
into a significant tropical cyclone (tropical depression) is
expected, but not within the next 24 hours. Invest 93W continues to
move slowly WNW. Convection has been persistent to the W through N
of the center, with scattered to numerous showers and isolated
thunderstorms found up to 330 miles from the center. Spotty showers,
though increasing, are also seen NE of the center. Invest 93W is
expected to slowly strengthen as it continues moving WNW to NW over
the coming days, passing N of Saipan late in the week.

For more information on Invest 93W, see bulletins issued by JTWC
under WMO header ABPW10 PGTW.

...OTHER WEATHER SYSTEMS...

MONSOON TROUGH...
The monsoon trough enters the WFO Guam Area Of Responsibility (AOR)
near 12N130E then heads eastward to a weak circulation near 12N142E
then turns east-northeastward to Invest 93W mentioned above and from
there turns east-southeastward to 8N180 and beyond. Scattered showers
are found in the northern Marshall Islands, with isolated
thunderstorms added to the north of Pohnpei and Chuuk States.
Scattered showers and isolated thunderstorms are noted to the
northwest of Palau. Little change in either location or intensity of
the monsoon trough is expected through Wednesday.

SURFACE TROUGHS...
A surface trough reaches from the weak circulation near 12N142E to
20N134E, then continues northward to 25N133E then to Typhoon Surigae
which is now north of the WFO Guam AOR. Scattered showers and isolated
thunderstorms are found west of the Marianas near the weak circulation
and far north of Palau to the south of Typhoon Surigae. This trough is
forecast to show little change of intensity and a slow westward
progression through Wednesday.

TRADE-WIND TROUGHS...
A trade-wind trough runs from Invest 93W to around 25N162E then
farther to the north-northeast. Scattered showers are seen west of
Wake Island. This trough is expected to continue progressing westward
with little change of intensity through Wednesday.

$$

Kleeschulte/Stanko