892
FXPQ50 PGUM 030752
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
552 PM ChST Thu Jul 3 2025

.Marianas Synopsis...
Gentle southerlies prevail, with satellite imagery and Doppler radar
indicating a few shallow cells on the outskirts of Guam and Rota
waters. The buoys indicate seas are around 3 feet.

&&

.Discussion...
A ridge has formed on the lee side of the monsoon trough shifting
northward, allowing a drier regime to return to the Marianas
overnight. Afterwards, showers and thunderstorms will begin to return
to the region as Tropical Storm Mun (formerly Tropical Depression
04W) southeast of Japan, continues to induce a strong monsoon pattern
across much of Micronesia immediately west of the Marianas. This, in
turn, will produce an unsettled weather pattern over the islands this
weekend.

&&

.Marine...
Combined seas of 3 to 4 feet are expected through much of the
weekend, before picking up another foot early next week. A moderate
risk of rip currents is expected along east facing reefs of the
Marianas for much of the week, with potential for the risk to become
moderate along west facing reefs once a secondary westerly swell
arrives in the first half of next week.

&&

.Eastern Micronesia...
There are a few major features across eastern Micronesia. The first
feature is near the Date Line, a trade-wind trough. This feature is
bringing scattered showers and isolated showers. The trough is
expected to make its way to Majuro in the next day or two.

The second feature is the persistent trade-wind trough that extends
from northern RMI south to Kosrae. This one is most convectively
active in the northern RMI, over Kwajalein, Wotje, Utirik, Ujae and
Rongelap islands and atolls. These showers are further being enhanced
by upper-level divergence associated with the Tropical Upper
Tropospheric Trough (TUTT). The showers near Kosrae are being
enhanced by increased convergence along the southern portion of the
trade-wind trough. This feature will gradually move westwards over
the coming days. Behind this on the time scale of 3 to 5 days out,
the trade-wind trough currently located near the Date Line is
anticipated to arrive at Kosrae.

The third area of interest is over Pohnpei. Surface level convergence
of both speed and direction is producing isolated to scattered
showers in the area. This will make way for the troughs mentioned
above, which look to arrive over the weekend and later next week
respectively.

Altimetry shows combined seas of 4 to 6 feet over the region. Winds
are expected to be light to moderate overall, with stronger winds
near heavier showers. Seas are expected to remain benign over the
forecast period.

&&

.Western Micronesia...
A mostly gentle westerly monsoon flow persists across Palau this
evening, with occasional moderate to fresh gusts from nearby showers.
Himawari visible satellite shows isolated to scattered showers
developing in the area, mainly to the west of Koror and near
Sonsorol, with patchy high-altitude cloud debris seen over much of
the region. To the east, a surface ridge is seen over Yap State,
currently located near Sorol and slowly shifting west toward Yap
Proper. Only isolated showers and partly cloudy skies are seen near
Yap Proper this evening, but showers are expected to increase
overnight. Model guidance points to increasing convergence within the
monsoon flow over far western Micronesia leading to a build-up of
showers overnight, mainly just west of Yap Proper over the Republic
of Palau. The increase from isolated to scattered showers was kept in
Yap`s forecast for tonight, and Palau`s Probability of Precipitation
(PoP) increases from 30 percent this evening to 50 percent after
midnight. A mostly gentle monsoon flow will persist into next week
across the region, but Palau and Yap can expect a relatively drier
weekend as a weak ridging pattern sets up across the area.

Chuuk can expect a mostly gentle trade flow through the weekend with
periods of scattered showers, associated with convergence along the
westernmost periphery of the ITCZ. Chuuk Lagoon currently sits along
a convergence boundary just east of a weak disturbance located over
Eauripik in Yap State, with scattered showers just to the south of
Weno. Quieter conditions are expected around Sunday as the ITCZ
retreats further east of the area.

Overall benign marine conditions continue. Despite mostly gentle
winds in the forecast, some fresh gusts will possible near heavier
showers and thunderstorms through the weekend. Combined seas of 3 to
5 feet across the region will come down a foot or so through the
weekend with swells and wind waves relaxing slightly.

&&

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

$$

Marianas: Montvila
East Micronesia: Bowsher
West Micronesia: DeCou