Area Forecast Discussion
Issued by NWS Tiyan, Guam

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450
FXPQ50 PGUM 220608
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
408 PM ChST Sat Mar 22 2025

.Marianas Synopsis...
Gentle to moderate trades prevail. Satellite imagery and Doppler
radar indicate high-level cirrus filaments present over the region.
The buoys indicate seas of 5 to 7 feet.

&&

.Discussion...
Little change has been made to the forecast. A minor surface trough
is expected to bring low-end scattered showers Sunday, followed by
mostly clear skies early next week. More trade troughs may be pushed
down by a passing subtropical high to the north, allowing a slight
uptick in showers sometime in the second half of next week.

&&

.Marine...
Combined seas of 6 to 8 feet will persist the next few days, before
tapering down a few feet by early next week as trade swell and
northerly swell weaken. A moderate risk of rip currents is expected
along north and east facing reefs for at least the next several
days, and along west facing reefs through tonight. Surf will continue
to diminish along all reefs, as trade swell and northerly swell
weaken.

&&

.Eastern Micronesia...
Dry conditions will continue across eastern Micronesia for the next
few days. Around the middle of next week, models continue to predict
the development of a band of convergence over the region, possibly an
Inter-Tropical Convergence Zone (ITCZ). The main area of convergence
looks to develop and remain south of Pohnpei and Majuro, with both
locations being on the northern periphery of the convection. POPs
(Probability of Precipitation) look to remain in the 30 to 40 percent
range for Majuro and around 30 percent for Pohnpei. Kosrae looks to
sit right in the middle of the strongest convergence, resulting in
POPs getting a bit higher. Due to the uncertainty of this pattern
developing and actual location, kept POPs between 30 and 50 percent
at Kosrae. Regardless, rainfall does not look to be real impressive.
By the end of next week, a drier pattern appears likely over the
Marshalls.

Marine conditions look to remain relatively unchanged through the
remainder of the weekend, with seas remaining in the 7 to 9 foot
range at all locations. Seas are then expected to begin to subside
Monday due to decreasing northerly and trade-wind swells. Seas should
drop to around 4 to 6 feet by the middle of next week. Moderate to
fresh winds look to subside as well, dropping to gentle to moderate
around the middle of next week.

&&

.Western Micronesia...
A broad trough and embedded disturbance in southern and western
Chuuk State remains poorly organized and has weakened over the last
24 hours. An ASCAT pass over the feature shows weak signs of
westerly flow into the disturbance and satellite and model trends
support that this will continue to open up into a trough and slowly
propagate westward. Still, showers and widespread cloudiness remain
across much of Chuuk State, including Chuuk Lagoon and southwestern
waters. Around midnight, we anticipate showers to decrease as
convergence weakens over Chuuk State and the feature progresses into
eastern Yap State. Farther west, only spotty showers are currently
over the main islands of Palau and Yap. Model guidance shows a
disturbance embedded in the Near-Equatorial Trough (NET). Although
this develops well southwest of the forecast locations, trailing
convergence will influence Yap and Palau weather over the next few
days. Additionally, the aforementioned trough near Chuuk is expected
to interact with the NET, bringing scattered to numerous showers to
Yap starting Sunday night, then to Palau starting Monday night.
Starting around the middle of next week, trade-wind convergence
strengthens across the region, keeping scattered showers in the
forecast for Palau and Chuuk, but relatively quiet conditions are
expect at Yap, being north of the pattern.

Altimetry and buoy data show combined seas of 5 to 7 feet at Yap and
Palau and up to 8 feet near Chuuk. Seas are expected to decrease by
one to two feet next week in response to slight decreases in easterly
trade swell and background northerly swell. Winds will generally be
light to moderate for Palau and gentle to moderate across Yap, with
winds increasing to moderate to fresh Monday through Tuesday at Yap.
For Chuuk, winds remain moderate to fresh over the next several days.

&&

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

$$

Marianas: Montvila
East Micronesia: Kleeschulte
West Micronesia: Cruz