374
AXPQ20 PGUM 010206
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1206 PM ChST Sat Nov 1 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...
Invest 98W, currently centered just southeast of Yap Proper near
8.9N 138.8E, moving west-northwest through Yap. Convection has
increased significantly as 98W has approached Yap Proper. Scattered
to numerous showers and isolated thunderstorms are found within 190
miles east of the center and up to 400 miles from the center
elsewhere. 98W is expected to continue moving west-northwest, moving
west of Yap Proper later today. As 98W progresses, it will maintain
the risk of heavy rainfall and gusty winds across Yap State and Palau
for the next couple of days. Invest 98W is now the subject of a
Tropical Cyclone Formation Alert (TCFA) by JTWC, meaning there is a
high potential for 98W to become a significant tropical cyclone
within the next 24 hours. This is most likely to occur northwest of
Yap Proper. Invest 98W will continue to be monitored closely for any
indications of more rapid development. Residents of western Yap State
and Palau should monitor forecast for any updates, changes, watches,
warnings or advisories.

For more information on Invest 98W and the TCFA, see bulletins
issued by the Joint Typhoon Warning Center under WMO headers ABPW10
PGTW and WTPN21 PGTW. There is also a Special Weather Statement for
Yap and Palau issued by the National Weather Service under WMO header
WWPQ82 PGUM.

Invest 99W, currently located near 11.8N 147.4E, is showing on the
latest ASCAT analysis as an open trough, moving west-northwest
toward Guam. 99W is currently very disorganized, with a couple of
weak spinners evident in the visible satellite data. Only spotty
convection is found with the weak spinners and trough. 99W is
currently rated low, which means development into a significant
tropical cyclone is possible, but not expected within the next 24
hours. Latest guidance indicates 99W will move west-northwest across
or just south of Guam, possibly becoming a tropical storm over the
Philippine Seas, west of the Marianas. Invest 99W will continue to be
monitored closely as it moves through the Marianas.

For more information on Invest 99W, see bulletins issued by the
Joint Typhoon Warning Center under WMO header ABPW10 PGTW.

A third disturbance is found over far eastern Micronesia, east of
Majuro to beyond the Date Line. A broad west-east oriented trough,
with a couple of weak circulations embedded along the trough, is
found from a weak circulation southwest of Kwajalein near 7N166E to
the second circulation centered near 5N169E, then continues beyond
the Date Line. Numerous showers are found southeast of Majuro to the
Date Line between 1N and 8N, with isolated showers found along the
trough and with the first circulation near Kwajalein. This trough
looks to slowly drift west over the coming days. Current guidance
indicates little change in intensity over the next few days.

...OTHER WEATHER SYSTEMS...

MONSOON TROUGH...
The monsoon trough enters the area near 19N130E, extending east to
Invest 99W, then turns east-southeast to end south of Invest 99W,
just south of Chuuk Lagoon, near 6N152E. Monsoon flow south of the
trough is feeding moisture into Invest 98W, assisting with
development. Farther south, monsoon flow is pushing isolated to
scattered showers and isolated thunderstorms across southern Palau
and Yap States, as far south as the equator. Widespread showers and
isolated thunderstorms are found along the far eastern end of the
trough over Weno, Chuuk in an area of enhanced convergence. The
trough is expected to continue to slowly extend east a bit farther
while drifting northward as Invests 98W and 99W move west-northwest.

TRADE-WIND TROUGHS...
Two trade-wind troughs are evident across the region. The first is
seen north-northwest of Pohnpei, extending north from near 8N156E to
end near 12N157E. Upper-level divergence associated with the TUTT is
enhancing convection with the trough to produce widespread showers
and isolated thunderstorms over a small area. This trough will
continue to move west, likely being absorbed by Invest 99W.

The second trade-wind trough extends north-northwest from the weak
circulation centered southwest of Kwajalein to end near 12N166E.
Scattered showers and isolated thunderstorms are found along this
trough, north of Kosrae. The trough looks to move slowly west with
the weak disturbance described in the last paragraph of the Special
Features section, with little change in intensity.

TUTT...
A weak TUTT enters the area near 25N169E, extending southwest
through a TUTT cell centered near 20N162E, to end near 10N150E.
Divergence southeast of the southern end of the TUTT is enhancing
convection along the far eastern end of the monsoon trough over Weno,
and along a weak trade-wind trough north-northwest of Pohnpei.
Otherwise, patchy clouds and showers with a couple thunderstorms are
found along the TUTT and TUTT cell. The TUTT and cell are expected
to drift west over the next couple of days with little change in
intensity.

...ITCZ...
The ITCZ is no longer evident across Micronesia.

$$

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