416
AXPQ20 PGUM 060109
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1109 AM ChST Tue Oct 6 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...
At 700 AM, Tropical Storm Koguma (27W) was centered 260 miles N of
Kwajalein near 12.5N 167.4E, moving NNW at 9 mph. Maximum sustained
winds were 45 mph. Most of the convection associated with Koguma is
found to the W through NNW of the center out to 210 miles, with
numerous to widespread showers and isolated thunderstorms found in
this area. A feeder band leading into Koguma is found NNW through NE
of the center from 165E to 170E, between 14N and 16N. TS Koguma is
expected to make a slow turn toward the NW, then WNW over the next
couple of days as it slowly strengthens, possibly becoming a typhoon
sometime Thursday.

For more information on TS Koguma, see bulletins issued by the Joint
Typhoon Warning Center under WMO header WTPN33 PGTW and from the
National Weather Service under WMO header WTPQ33 PGUM.

...OTHER WEATHER SYSTEMS...

MONSOON TROUGH...
The monsoon trough enters the region near 12N130E, extending NE to
near 22N145E, where it becomes very diffuse as it re-establishes
farther S from TY Choi-wan, then turns back to the SE into TS
Koguma. It then takes a NE to SE arc, crossing the Date Line near
13N. A band of convergence S of the trough is producing scattered to
numerous showers and isolated thunderstorms from W to N of Palau,
across Yap and Ngulu to NE of Ulithi. Farther E, a second band of
convergence interacting with a surface trough is generating
scattered to numerous showers and isolated thunderstorms E of the
Marianas. Weak convergence S of the trough is also producing
scattered showers and isolated thunderstorms across Pohnpei and
Kosrae, with isolated to scattered showers seen over the Marshall
Islands. The monsoon trough looks to reorient farther S from the E
of the Marianas W to beyond 130E as the trough continues to break
away from Choi-wan. The rest of the trough looks to remain quasi-
stationary. No changes in the strength of the trough is expected.

SURFACE TROUGHS...
A surface trough is found E of the Marianas extending SSE from E of
Alamagan near 17N148E to 12N151E. This trough is interacting with
convergence S of the monsoon trough to generate scattered to numerous
showers and isolated thunderstorms. The trough will continue moving E
over the coming days with little change in intensity.

$$

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