056
FXPQ50 PGUM 102006
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
606 AM ChST Sat Oct 11 2025

.Marianas Update...
An isolated shower trade-wind regime is expected to remain in place
through at least the weekend. A tropical disturbance from Micronesia
could come through during the first half of the week, at the moment
though, it`s just a trough, so rather disorganized, with no
circulation. So we may get winds increased to 15 or 20 mph, more
showers, etc. but not expecting anything more profound than that at
this time.

Marine conditions could see seas peak at 5 to 7 feet around Monday or
Tuesday, then begin to diminish. Winds are forecast to peak between
15 and 20 knots. These are both short of Small Craft Advisory
criteria, with the GEFSwave predicting only a 10 percent or so
chance of that.

&&

.Eastern Micronesia Update...
Pohnpei is north of the main band of showers associated with a
southwest to northeast oriented trade-wind trough, and should remain
so today, and possibly tonight. By Sunday, they will be in it, and
should remain so through Tuesday, then dry out a bit for Wednesday.
Kosrae and Majuro are both in the thick of it right now. Majuro could
dry out tonight, and Kosrae perhaps Sunday night. The next trough
could affect Majuro as early as Sunday and Kosrae by Tuesday.

Marine conditions are forecast to have winds 5 to 10 knots and seas 4
to 6 feet throughout Eastern Micronesia. These figures are
substantially below Small Craft Advisory criteria, of which there is
little or no chance.

&&

.Western Micronesia Update...
Yap and Koror, Palau will be dry through Sunday as a ridge behind the
departing Tropical Storm Nakri remains nearby. Then the trough
leading to the tropical disturbance near Chuuk will bring limited
scattered showers to Yap and Palau Monday through Wednesday.

Chuuk is within the trough that could become a tropical disturbance
later in the Marianas. It`s expected to continue to have showers
through Tuesday.

Marine conditions are expected to include 5 to 10 knot winds at Koror
for the entire forecast period, while at Yap and Chuuk, winds will be
5 to 10 knots today through Monday, and 10 to 15 knots for Tuesday
and Wednesday. For seas, Chuuk will be 3 to 5 feet through Sunday
night, then 4 to 6 feet through Wednesday. Yap will be 3 to 5 feet
through the entire forecast period. Koror, Palau will be 2 to 4 feet
through the entire forecast period. These are all well below Small
Craft Advisory criteria, of which there is little or no chance.

&&

.Prev discussion... /issued 642 PM ChST Fri Oct 10 2025/

Marianas Synopsis...
Satellite imagery shows cloudy skies, while radar imagery shows
isolated showers across the Marianas. Altimetry shows combined seas
of 3 to 4 feet, while the buoys show 2 to 3 foot seas.

Discussion...
After a formation of a meso-high that is moving out of the area, a
light to gentle trade-wind pattern is expected to move into the
region tonight. This will briefly introduce drier conditions to the
area, with only isolated showers expected over the weekend. After, a
potential tropical disturbance in central Micronesia is expected to
make its way toward the Marianas in the first half of next week,
producing a convergence zone that may bring scattered showers and
isolated thunderstorms around the middle of next week. Model guidance
has been shifting this system more east and north than previously
anticipated, but it still remains unlikely to develop into a
significant tropical cyclone during its passage. Conditions are
expected to improve considerably once this feature moves out of the
area before the next weekend.

Marine...
Winds are expected to be light to gentle for the next day or so, and
will build to moderate by Sunday. Combined seas of 3 to 5 feet will
persist through Saturday, to then build to 5 to 7 feet thereafter, as
a long-period north swell moves through the region from the distant
Typhoon Halong. There will be a moderate risk of rip currents along
east facing reefs, with a low risk along all other reefs. When the
swell from Typhoon Halong arrives, the surf and risk of rip currents
will increase as well along north facing reefs. Seas, surf and risk
of rip currents may start to fall around the middle of the next week.

Eastern Micronesia...
The Tropical Upper Tropospheric Trough (TUTT) cell that was
previously located east of Wake Island has moved southwest, and is
now helping to enhance convection along the Intertropical Convergence
Zone (ITCZ)-like trough located over the central Marshall Islands.
This led to persistent heavy showers and thunderstorms overnight
through this morning, which brought over 4 inches of rainfall to
Majuro in just a 12-hour period. Satellite this afternoon shows that
numerous showers and isolated thunderstorms continue across the area,
but are now focused further north and west of Majuro, across the
northern half of the RMI. Scattered showers are expected to build
overnight for Kosrae as the trough shifts further west. There is also
a weak trough and area of surface convergence just south of Pohnpei,
which will support scattered showers there tonight as well. The
trough over the RMI will continue to shift west and enhance showers
and thunderstorms over Kosrae this weekend, and later Pohnpei through
early next week. Numerous showers are expected for Kosrae around
Saturday night, with locally heavy rainfall possible. Majuro will see
a brief lull this weekend as the the trough moves out, but the next
disturbance will begin to build in around Monday morning, continuing
a wet pattern over much of the Marshall Islands for the first half of
next week.

Benign marine conditions continue across the region, with buoys and
altimetry indicating combined seas of 2 to 4 feet for Pohnpei and
Kosrae, and 3 to 5 feet for Majuro, comprised of mixed swell mainly
from the north-northeast and south-southeast. Seas will increase by
a foot or two late this weekend through early next week as a long-
period north swell arrives, generated by distant Typhoon Halong and
Tropical Storm Nakri. Marine and surf hazards are not expected at
this time, but the incoming swell will be closely monitored as surf
may approach hazardous levels of 9 feet along north-facing reefs of
Pohnpei and Kosrae. Additionally, the Coastal Flood Advisory for
Majuro has been extended until 3 AM ChST. Minor inundation has been
observed along low-lying areas, and predicted water levels continue
to show a possibility for minor flooding through the evening, for
several hours after peak tide.

Western Micronesia...
Newly-formed doldrums spanning much of western Micronesia will bring
a relatively quiet weather pattern in the first half of next week to
Palau and Yap, as mid to upper level relative humidity is
considerably drier than usual for this time of year. As such, this
will provide little moisture flux needed for a tropical disturbance
to consolidate further once it tries to form in eastern Yap State
during the weekend. Even so, the aforementioned tropical disturbance
may still bring a period of unsettled weather to Chuuk Monday and
Tuesday, as a convergence zone builds into central Micronesia
upstream. This potential disturbance is expected to move north
toward the Marianas by the middle of next week, allowing a drier
regime to ensue at Chuuk, and continue at Palau and Yap.

Combined seas of 3 to 5 feet are expected across the region through
the weekend, before increasing slightly near Chuuk as a northerly
swell emanating from a distant Typhoon Halong well north of
Minamitorishima, makes its way across the area. Northerly swells will
begin to overtake the southwest swell that was dominating much of
Palau and Yap waters the last few days, which will cause surf to
build along north-facing reefs, while diminishing along south and
west reefs of Palau and Yap. At this time, no significant marine
and/or surf impacts are expected by these swells.

&&

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

$$


Marianas/East and West Micronesia Update: Stanko
Marianas: Bowsher
East Micronesia: DeCou
West Micronesia: Montvila