136
FXPQ50 PGUM 271907
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
507 AM ChST Fri Nov 28 2025

.Marianas Update...
Partly cloudy skies and isolated showers will reign over the Marianas
Waters through tonight. After that mostly cloudy skies and scattered
showers could build in from the near-equatorial trough to the south.
There is an area of showers just south of Guam on radar right now,
which is expected to move off to the west in the next hour or two,
and most of it will pass south of Guam, so for those two reasons it
won`t matter much and is not included in the forecast.

&&

.Marine...
The marine forecast is pretty straightforward through the weekend.
Next week will be the time to watch, the question is whether a storm
system that moved eastward from Japan generated a good bit of north
swell, and how much of it would hit us. Seas are currently forecast
to be 5 to 7 feet, but if the north swell should turn out to be
substantial, the seas could be as high as 7 to 9 feet. That`s under
Small Craft Advisory criteria, but could trigger a High Surf
Advisory and a High Risk of Rip Currents.

&&

.Eastern Micronesia Update...
The forecasts for Kosrae and Majuro looked fine and no changes were
needed. A large area of mid-level clouds has been hanging over that
area, but is now gradually diminishing, with Majuro at the edge and
Kosrae under a separated shred that is likely decaying, so the
forecast of mostly sunny made sense. For Pohnpei, the convection was
less than forecast. While the PoP`s are still listed as 50 percent,
that is now just the southwest corner of the waters. Over Pohnpei
itself, the chance of showers will be more like 30 percent as the
trade-wind trough exits the area.

&&

.Western Micronesia Update...
The numerous showers for Chuuk don`t seem to have really panned out
either. However, with showers poised to move over them now, the
scattered showers for today looked good. While there aren`t many
showers over Yap now, there are enough in the area that scattered
seemed like a good bet there also. And in Koror Palau, the showers
that move in keep dissipating as they move in, so the isolated
shower forecast there looks good also. Therefore, no changes were
needed in Western Micronesia.

&&

.Prev discussion... /issued 603 PM ChST Thu Nov 27 2025/

Marianas Synopsis...
Satellite imagery shows partly cloudy skies, while radar imagery
shows isolated showers over the coastal waters. Altimetry shows
combined seas of 5 to 6 feet, while buoy data shows heights of 5 to
6 feet.

Discussion...
Only minor edits were needed to the forecast today. Mostly pleasant
weathers is expecting through Saturday. The Probability of
Precipitation (PoPs) is expected to be around 20 percent. The next
chance for showers is expected for Saturday as a broad trough enters
the region and interacts with an upper-level high. This interaction
is expected to produce high-end (50 percent) scattered showers and
isolated thunderstorms. Once this trough passes, pleasant weather may
return for the middle of next week.

Marine...
Gentle to moderate trades will prevail across the region through the
end of the week. Combined seas of 5 to 7 feet will gradually fall to
around 5 feet over the next few days, before potentially increasing
toward the end of the weekend, as a northerly swell generated by
distant synoptic features strengthens. A moderate risk of rip
currents is expected to persist along east facing reefs for at least
the next several days. Rip risk may become moderate along north
facing reefs this weekend, as a northerly swell moves through the
region. A moderate risk of lightning is expected for Saturday through
Tuesday as an incoming trough moves through the region.

Eastern Micronesia...
The main item of interest will be a building north swell towards end
of the weekend. Some of the models suggest this could even move into
Pohnpei`s and Majuro`s coastal waters late Saturday evening. As such,
seas of 5 to 7 feet (highest along Majuro`s northern and eastern
atolls) will increase 1 to 2 feet by the weekend. During this time
winds may increase into the moderate to fresh range at Majuro,
remaining gentle to moderate elsewhere. Looking towards next week, the
next King Tide cycle is coming up with the full moon on December
4th, so high tides will be elevated for a few days before and after
the full moon. This will increase the potential for some minor
coastal inundation, especially at vulnerable islands/atolls if there
is a long period swell also impacting the region.

As for those rain chances, Pohnpei will see numerous showers through
mid morning Friday, as a surface trough takes it`s time departing the
area. Then, showers will become isolated coverage, which Kosrae and
Majuro can expect (isolated showers) tonight. This trend will
continue through at least the start of the weekend, before increasing
rainfall potential develops during the first half of next week.

Western Micronesia...
Convergent flow along the northern side of the Near-Equatorial
Trough (NET) just stalled east of Palau and Yap earlier today,
keeping weather conditions drier than previously expected. However,
scattered showers and isolate thunderstorms are now starting to push
into Yap and nearby coastal waters, and this convergent flow is
expected to remain near Yap into the weekend, keeping scattered
showers and isolated thunderstorms in forecast through at least
Saturday night. Models then support drier conditions by the
beginning the upcoming week. Southeast of Palau, visible satellite
and ASCAT wind analysis show a very weak, elongated circulation
within the NET, centered near 5N137E, and associated with some
scattered showers and isolated thunderstorms. Model guidance suggest
this weak circulation will shift west northwest, bringing scattered
showers and isolated thunderstorms to Palau later tonight, and then
keeping winds fairly light for the next several days. These light
winds may spark some isolated island-effect showers and thunderstorms
during the day time hours of Friday, and this will have to be
reevaluated again for Saturday and Sunday. Otherwise, the forecast
for Palau is fairly dry except for the Saturday night, when models
show the convergent flow near Yap briefly shifting towards Palau. For
Chuuk, the overall wet pattern is developing as expected, with
scattered showers and isolated thunderstorms extending across the
state. A broad trough is currently near Pohnpei and is slowly
drifting westward, so expected showers to increase to numerous later
tonight and again Friday night as this trough moves through Chuuk.
Once the trough shifts west of Chuuk, the potential for showers will
decrease but will hover around 30-40 percent through the weekend and
into early next week, due to the convergent flow associated with the
NET continues to extend across Chuuk State.

Latest altimetry data indicates combined seas are between 4 and 6
feet near Palau and Yap and 5 and 7 feet near Chuuk. Winds are
gentle to moderate around Palau and Yap, with some gusts around 25 kt
at Chuuk due to nearby convection. Winds will being to decrease
slightly Friday and into early next week as the NET lifts northward
towards the islands, but gusts are still possible near convection,
especially in Chuuk State. The northeast trade swell will also slowly
subside over the next couple of days, allowing seas heights to drop
a couple of feet. Late this weekend and into next week, a long-
period north swell will move into the region and will build surf
along north-facing reefs. Wave models suggest surf will remain below
hazardous levels of 9 feet at Palau and Yap, but depending on the the
strength of the primary northeast trade swell, surf may push up to 9
feet at Chuuk. Seas are expected to peak around 5 and 6 feet near
Palau and Yap and around 7 to 8 feet at Chuuk by the middle of the
week. Also looking towards to next week, the next King Tide cycle is
expected to occur with the full moon on December 4th, meaning high
tides will be elevated a few days before and after the full moon.
This will increase the potential for some minor coastal inundation,
especially at vulnerable islands/atolls if there is a long period
swell also impacting the region, like the long-period north swell
expected during the beginning of December. During the new moon back
on November 20th, and the last King Tide cycle near the beginning of
November with the previous full moon, Chuuk did experience some
coastal flooding, so this increased potential for coastal inundation
is something to watch for during the first week of December.

&&

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

$$


Marianas/East and West Micronesia Update: Stanko
Marianas: Bowsher
East Micronesia: Doll
West Micronesia: Schank