954
FXPQ50 PGUM 060800
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
600 PM ChST Mon Oct 6 2025

.Marianas Synopsis...
Satellite imagery shows partly cloudy skies, while radar imagery
shows a few island effect showers near northern Guam. Buoy data shows
sea heights of about 2 to 3 feet. Altimetry confirms these heights.

&&

.Discussion...
The main weather concern is the arrival of Invest 95W which is
anticipated to arrive around Tuesday to Tuesday night. This system
is expected to bring scattered showers and isolated thunderstorms.
Winds are also to increase as this system passes over the Marianas.
Pleasant weather is anticipated to return around Wednesday and last
through the weekend. There is one caveat though, showers moving
along a broad trough in Yap State may spread into the Marianas
around Thursday, however, it is not certain whether or not this will
come to pass.

&&

.Marine...
Combined seas of 2 to 3 feet and light to gentle winds are expected
to build tonight and Tuesday as a tropical disturbance (95W)
approaches the region. Seas are expected to build to 6 feet by
Tuesday night. Seas and winds will then decrease Wednesday as Invest
95W moves northwest and away from the region. There is a moderate
risk of rip currents along east facing reefs is expected through
Tuesday night. Surf is expected to start diminishing around
Wednesday. There is also a moderate risk of lightning through
Wednesday.

&&

.Tropical Systems...
Invest 95W is centered near 12N149E, with a trough extending west-
northwest to end near 14N140E, passing through southern Guam waters.
Another trough extends east-southeast to end near 11N152E, north of
Weno, Chuuk. 95W has an elongated center and is still fairly
disorganized. Moderate to deep convection associated with 95W and the
convergent southwesterly flow in its wake is found southwest of the
center, with scattered to numerous showers and isolated thunderstorms
found from just south of Eauripik, Satawal and Polowat to around
12N, stretching across much of eastern Yap State and western Chuuk
State. Invest 95W is expected to continue to move northwestward,
moving across the Marianas Tuesday and Tuesday night, with little, if
any, change in intensity.


&&

.Eastern Micronesia...
An elongated trough extending ENE between Pohnpei and Kosrae is
interacting with upper-level divergence and weak surface convergence
to generate scattered showers and isolated thunderstorms across
Pohnpei and west of Kosrae. This trough will continue to move
northwest overnight, maintaining this convection over Pohnpei. By
Tuesday morning, a drier pattern is expected to move into Pohnpei as
the trough clears out of the area. For Kosrae, showers associated
with the aforementioned trough has moved out of the area, bringing
isolated showers to the island. To the east of Kosrae, scattered
showers and isolated thunderstorms that are currently evident on
satellite are expected to decrease as they move west, with the
associated trough losing influence of upper-level divergence. If the
divergence pattern decides to shift farther west, showers may need to
be increased for Kosrae Tuesday. Otherwise, a dry pattern looks to
continue for Pohnpei and Kosrae through midweek. Around midweek,
models indicate that another Inter-Tropical Convergence Zone (ITCZ)
will develop across the region, bringing increased convection back to
both locations into the weekend.

For Majuro, the ITCZ that was there has weakened significantly and
pushed north, allowing a dry pattern to move over the atoll. This dry
pattern looks to continue through the end of the week. The ITCZ that
is expected to develop around midweek looks to remain far enough
south of Majuro that little, if any, increase in convection is
expected until early in the weekend. This is when a more robust
trade-wind trough is expected to move in from east of the Date Line,
pulling the ITCZ farther north.

Marine conditions will remain fairly benign as winds are expected to
be mostly light to gentle into the weekend. The only exception is for
a brief period of gentle to moderate winds for Pohnpei Tuesday as
slightly stronger winds south of the aforementioned trough move
through. Combined seas are expected to be between 3 and 4 feet for
Kosrae and Pohnpei, and between 3 and 5 feet for Majuro. Also for
Majuro, elevated tides due to the full moon phase are expected to
maintain the potential for minor inundation during high tide.
Therefore, the Coastal Flood Advisory continues through Thursday
afternoon.

&&

.Western Micronesia...
Invest 95W continues move northwest, pulling away from Chuuk. ASCAT
analysis places a circulation near 12N149E, about 350 miles
northwest of Weno. The bulk of convection has shifted off to the
northwest, although some patchy showers still linger along weak
convergence over Chuuk. Showers are expected to trend down to
isolated Tuesday, then scattered showers build back in Tuesday night
and Wednesday as an ITCZ fragment lifts northwest into the area.

Farther west, widespread clouds and showers extend across much of Yap
State from convergent southwesterly flow into 95W. Showers are slow
to build into Palau, but an increase in showers are expected later
tonight as broad cyclonic flow to the northwest begins to steer some
of the moist southwesterly flow. Unsettled weather is expected for
Yap and Palau over the next several days due to this monsoon-like
pattern over Palau and Yap. By late week, southwesterlies weaken as
95W passes to the distant north, but a trade-wind pattern begins to
push in from the east, possibly prolonging scattered showers through
the weekend.

Scatterometry and altimetry data indicates benign marine conditions,
light to gentle winds and combined seas of 2 to 3 feet near Yap and
Palau and up to 4 feet near Chuuk. Winds are expected to be light to
moderate decreasing to light to gentle in the latter half of the
week. A pulse of southwest swell is expected to build into Palau
waters Tuesday and then Yap Thursday, driven by a developing monsoon-
like pattern. This will also cause seas to build to 3 to 5 feet
around midweek. Longer-period northerly swell is expected to move
into the region late week and over the weekend, emanating from
Tropical Storm Halong to the distant north. This will cause surf to
build along north-facing reefs, first to Yap and Palau, then to
Chuuk around Sunday. No marine and surf hazards are expected at this
time.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...None.
MP...None.
Marianas Waters...None.
&&

$$

Marianas: Bowsher
Tropical: Kleeschulte/Cruz
East Micronesia: Kleeschulte
West Micronesia: Cruz