650
FXPQ50 PGUM 151814
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
414 AM ChST Mon Jun 16 2025

.Marianas Update...
The forecast remains in good standing. Partly cloudy skies with
isolated showers are expected for the forecast period. Seas are
expected to be benign with combined seas of 2 to 4 feet. Surf has
also fallen, allowing the risk of rip currents to drop to low for all
reefs. Winds are expected to be light to gentle for the beginning of
the week. Then, winds may build to light to moderate around the
middle of the week. Time heights suggests a moisture pocket to move
into the region around the middle of the week, however, moisture
alone is not enough to bring in more showers.

&&

.Eastern Micronesia Update...
Kosrae:
The Inter-Tropical Convergence Zone continues to build in, fueling
new convective development that looks to mainly affect Kosrae. As
such, based on satellite trends we bumped Kosrae`s rainfall potential
up to 90 percent for today and added locally heavy rainfall wording.
For Tonight, numerous shower coverage with 60 percent probabilities
gives us a good "starting point". The day shift can re-access this
to see if higher probabilities are needed.

Pohnpei and Majuro:
No major updates were needed, as satellite trends and analysis are
in good agreement.

&&

.Western Micronesia Update...
No significant updates were needed as the forecast looks to be in
good shape. In general, an unsettled pattern will continue to bring
rounds of scattered showers, with a thunderstorm or two mixed in from
time to time.

&&

.Prev discussion... /issued 314 PM ChST Sun Jun 15 2025/

Marianas Synopsis...
Satellite and radar observations show a few clouds with isolated
showers across the Marianas. Ritidian and Ipan buoys show combined
seas between 2 and 4 feet.

Discussion...
Quiet conditions prevail across the region. Isolated showers are
generally favored throughout the whole forecast period. There are
some hints towards an increase in moisture for Guam Monday night
into Tuesday, which could allow for some scattered showers, but
guidance is still inconsistent and upstream PWATS remain
unimpressive. For now, kept PoPs isolated for everyone and will let
the next couple of shifts take a closer look at it. This pattern with
prolonged dry stretches with short periods of increased showers
looks to persist over the next week or so.

Marine...
Marina conditions remain benign with combined seas between 2 to 4
feet. Seas look to fall a foot or so tonight before rising to 3 to 5
feet on Wednesday. The moderate risk for rip currents along east
facing reefs is expected to fall to low on Monday as the easterly
swell decreases.

Eastern Micronesia...
A relatively dry pattern is currently in place for Pohnpei and
Majuro. This is not the case, however, for Kosrae. The ITCZ is making
itself known over the southern portion of eastern Micronesia. Along
with the ITCZ, a few weak trade-wind troughs are interacting with the
ITCZ. The strongest convection, with numerous to widespread showers
and isolated thunderstorms, is found over and east of Kosrae. This is
where the strongest of the troughs and the strongest convergence
along the ITCZ is found. Based on satellite trends, decided to
maintain numerous showers for Kosrae through Monday afternoon as a
couple of trade-wind troughs traverse the area, enhancing convection.
The latest CIMMS MIMIC Precipitable Water (PWAT) product shows
increasing PWATs, in excess of 3 inches, to the east of Kosrae. With
this much moisture in the area, decided to add locally heavy showers
wording to the forecast. Latest model guidance keeps a wet, unsettled
pattern across Kosrae for the next several days with and ITCZ and
trade-wind troughs maintaining convection over the island. This
pattern looks to remain mostly to the south of Majuro and Pohnpei.
However, Pohnpei can expect to see a brief period of low-end
scattered showers later tonight through Monday morning as the trough
currently moving through Kosrae brushes the coastal waters. The ITCZ
does look to fluctuate in both intensity and location through the
week, bringing periods of scattered showers to Majuro beginning
Monday night and at Pohnpei Tuesday night. Overall, very wet
conditions at Kosrae for the next several days, with Pohnpei and
Majuro only seeing periods of convection.

The marine forecast remains relatively unchanged. Mostly gentle to
moderate trade-winds are expected for Pohnpei and Kosrae, with
occasional fresh winds at Majuro. Combined seas look to stay between
4 and 6 feet across Pohnpei and Kosrae, and 5 to 7 feet across
Majuro.

Western Micronesia...
A fairly unsettled and disorganized weather pattern continues over
far western Micronesia. Scattered showers are seen across the region,
mainly just west of Palau and south of Yap Proper, due to a broad
surface trough extending eastward into the area from over Mindanao,
and associated trade-wind convergence upstream. Conditions are
slightly drier than the last few days, likely influenced by a surface
ridge extending south-southwest across Koror and Yap Proper. Model
guidance keeps most of the showers west of the area for tonight,
before a trade-wind trough moves west across Yap State tomorrow
morning and into the Republic of Palau, increasing showers across the
area through Monday night. Quieter conditions will resume for Palau
and Yap Tuesday through Wednesday, before a disturbance begins to
develop southwest of Palau around Wednesday night, increasing showers
through the rest of the week.

Quiet conditions continue over Chuuk State, with satellite showing
partly cloudy skies and isolated showers throughout the region this
afternoon. Models show scattered showers developing near Chuuk Lagoon
tonight and Monday as a weak trough or two move west across the area.
Fairly quiet conditions will prevail throughout the week as these
disorganized, transient features increase showers from time to time,
with most of the showers staying south of Weno. However, model
guidance shows the ITCZ organizing across the region toward the end
of the week as it lifts north over Chuuk, which would bring much
wetter conditions by next weekend.

Combined seas of 2 to 4 feet over Yap and Palau waters and 3 to 5
feet near Chuuk will continue for the next few days, increasing a
foot or so around midweek as trade swell builds slightly. Palau may
experience a southwest swell of around 2 feet from Monday through
Tuesday night, driven by monsoon-like flow further south. Yap may
see just the eastern edge of this swell energy later around Tuesday,
and a 2-foot south swell has been included there.

&&

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

$$

Marianas Update: Bowsher
East/West Micronesia Update: Doll
Marianas: Williams
East Micronesia: Kleeschulte
West Micronesia: DeCou