Rip Current in Guam, March 22, 2025

Area Forecast Discussion
National Weather Service Tiyan GU
403 AM ChST Sat Mar 22 2025

.Marianas Update...
Satellite observations show widespread cirrus moving across the
Marianas this morning. Only minor changes were made to the forecast.
PoPs were bumped up to 20% but still remain in the isolated category.
Radar shows a few showers across the Marianas. A brief downpour
cannot be ruled out.

Combined seas remain between 6 to 8 feet. There is a moderate risk
for rip currents along west, north, and east facing reefs. Seas are
expected to fall the latter half of the weekend and rip current
conditions may fall to low for west facing reefs by Sunday night and
east and north facing reefs early next week.

&&

.Eastern Micronesia Update...
Only minor edits to the forecast this morning. The dry trade-wind
pattern continues this weekend. Satellite imagery is showing a subtle
trade disturbance and increase in moisture pushing away from Kosrae
and into Pohnpei this morning, bringing low-end scattered showers to
Pohnpei today. The Inter-Tropical Convergence Zone (ITCZ) looks to
develop across the region next week, with and increase in showers and
thunderstorm potential expected.

The increased trade swell and gusty trade winds will keep marine
conditions elevated through the weekend, but likely below hazardous
to small craft levels. Seas 7 to 9 feet and moderate to fresh winds
expected into early next week. A High Surf Advisory for east reefs of
Kosrae continues as well.

&&

.Western Micronesia Update...
Only minor edits to the forecast this morning. A surface trough with
an embedded disturbance is southwest of Chuuk and slowly working
west. Convergence along the eastern flank will bring scattered
showers and isolated thunderstorms to Chuuk today and tonight, with
isolated trade showers then expected into early next week. Another
surface trough pushing away from Yap and towards Palau will bring
scattered showers and isolated thunderstorms for Palau today with
mainly isolated showers for Yap. A Near-Equatorial Trough (NET)
disturbance develops over the coming days, working into Yap by
Sunday night and Palau on Monday, creating another period of
increased showers and thunderstorm potential.

Seas 4 to 6 feet for Palau, 5 to 7 feet for Yap, and 6 to 8 feet for
Chuuk through the weekend. Seas look dip one to two feet next week
in response to slight decreases in easterly trade swell and
background northerly swell. In general, winds will be gentle to
moderate across Yap and Palau and moderate to fresh for Chuuk over
the next several days.

&&

.Prev discussion... /issued 412 PM ChST Fri Mar 21 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 6 to 7 feet.

Discussion...
Much more pleasant weather will continue across the Marianas, with
mostly clear skies expected early next week. Minor 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 7 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 west, north, and east facing reefs for at least the next
several days. Surf will begin to diminish along all reefs starting
Sunday, as trade swell and northerly swell weaken. This may allow
the rip current risk to drop to low along west facing reefs as early
as Sunday night.

Eastern Micronesia...
A dry trade-wind pattern continues to dominate across eastern
Micronesia this afternoon. This dry pattern is expected to continue
through the weekend and into the beginning of next week. Latest
model guidance shows a band of convergence, possibly an Inter-
Tropical Convergence Zone (ITCZ), developing across the region. This
could bring another round of showers to the region, beginning as
early as Tuesday night. Kosrae looks to receive the majority of the
convection, with Majuro and Pohnpei remaining on the northern edge of
the heaviest rainfall. Based on low-confidence, kept probability of
showers at 30 to 40 percent.

Seas and wind have subsided sufficiently across the Marshall Islands
to allow the Small Craft Advisory for Majuro to expire this
afternoon. Due to an increased trade swell, seas look to hover
around the 8 to 9 foot range through the weekend. The trade swell
will remain high enough to maintain hazardous surf along east facing
reefs of Kosrae into next week. Moderate to fresh winds are expected
to continue into the middle of next week.

Western Micronesia...
An unsettled weather pattern stretches across southern Chuuk State
and extends into eastern Yap State associated with a broad surface
trough and embedded disturbance. Another trough to the west is
generating some showery weather over Palau and in Yap's southwestern
waters. Overall, convection is poorly organized, and model guidance
indicates a weakening trend in both features over the next couple
days. The trough in far western Micronesia is expected to bring
scattered to numerous showers and isolated thunderstorms to the main
islands of Palau through tonight. Meanwhile, the showers near Yap
Proper will continue to shift westward, leaving only isolated
showers over the island tonight. The bulk of showers near Chuuk
remains to the south, but satellite shows a small area of showers
that will continue to move across Chuuk Lagoon this evening. Over the
weekend, models show off-and-on showers along weak troughs in the
trade flow for all forecast locations. Then, a Near-Equatorial Trough
(NET) disturbance begins to take shape in far western Micronesia
early next week, creating another period of showery weather for Yap
and Palau.

Altimetry data indicates combined seas are 5 to 7 feet within Palau
and Yap coastal waters 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.
In general, winds will be gentle to moderate across Yap and Palau
and moderate to fresh for Chuuk over the next several days.

&&

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

Marianas: Williams
East/West Micronesia: Slagle