Area Forecast Discussion
Issued by NWS Tiyan, Guam

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FXPQ50 PGUM 030611
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
411 PM ChST Sun Aug 3 2025

.Marianas Synopsis...
Satellite imagery shows partly cloudy skies across the Marianas
while Doppler Radar shows isolated showers. Altimetry and Buoy data
shows combined seas between 4 to 6 feet.

&&

.Discussion...
Quiet conditions are seen across the Marianas this afternoon.
However, scattered showers are seen just outside Guam`s coastal
waters and should enter the region over the next couple of hours.
Scattered showers remained in the forecast for tonight, though radar
trends suggest there could be an opportunity for higher shower
coverage across Guam. After a brief lull on Monday, shower activity
looks to remain scattered due to passing trade-wind convergence,
surface troughs, and weak circulations. PoPs may need to be
increased Tuesday and Wednesday as both the GFS and ECMWF show a
monsoon-like pattern with westerly winds just to our west and
southeasterly winds just to our east, leading to surface convergence
over the Marianas. For now, kept PoPs at 30%, but high end scattered
to low end numerous showers may be necessary with future forecasts.

&&

.Marine...
Combined seas look to remain benign the next several days with 4 to
6 foot seas falling to 3 to 5 feet late tonight into Monday. The
primary westerly swell will diminish late tonight, becoming a
secondary swell to the east swell by Monday night. A moderate risk
for rip currents will continue across west, north, and east facing
reefs through Monday before decreasing to low on west and north
facing reefs Monday night.

&&

.Eastern Micronesia...
The Inter-Tropical Convergence Zone (ITCZ) has dissipated across
eastern Micronesia. With only weak trade-wind troughs expected to
move through the region over the next few days, a dry trade-wind
pattern looks likely for the most of the week at Kosrae and Majuro,
and for the entire week at Pohnpei. For Majuro and Kosrae, a weak
transient band of convergence looks to move through the area around
Thursday, bringing a brief period of scattered showers to both
locations as the band moves through.

A relatively benign marine forecast will continue across the region.
Pohnpei and Kosrae will see gentle to moderate winds through Tuesday,
becoming light to gentle, with combined seas of 3 to 4 feet. Majuro
will see light to gentle winds and combined seas of 4 to 5 feet
through the week.

&&

.Western Micronesia...
Yap has a weak circulation passing not too far to the north. This
will bring some scattered showers over the next few days, and the
showers might even dip down toward Koror, Palau at times. Chuuk has a
similar feature passing to their south, and could see some scattered
showers the next few days. Specifically, Koror could see isolated
showers tonight become scattered Monday, and these could last through
Thursday, becoming isolated again by Friday. Yap could see scattered
showers that might last through Thursday, becoming isolated by
Friday. And Chuuk could see scattered showers that might last through
Tuesday, becoming isolated by Tuesday night, then they could become
scattered again during the last half of the week.

For the Chuuk marine forecast, winds will be capped at 10 knots. Seas
will be in the 3 to 4 foot range, leading to benign weather
conditions expected. In the Yap Waters, winds will also be capped at
10 knots. Seas will be around 3 feet, also leading to benign weather
conditions expected. Near the Koror, Palau Waters, winds could reach
10 knots Tuesday and Tuesday night, but will mostly be capped around
5 knots. Seas will range from 2 to 3 feet, and it`s difficult to see
how you could get more benign than that.

&&

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

$$

Marianas: Williams
East Micronesia: Kleeschulte
West Micronesia: Stanko