Drought in Guam, May 13 to 31, 2025

Area Forecast Discussion
National Weather Service Tiyan GU
515 PM ChST Tue May 13 2025

.Marianas Synopsis...
Partly cloudy skies with only spotty showers and moderate to fresh
trade winds prevail across the Marianas this afternoon. Buoys show
seas between 5 and 7 feet. A Red Flag Warning remains in effect
through Thursday afternoon.

&&

.Discussion...
A dry trade-wind pattern remains across the Marianas and looks to
continue for at least the next week. POPs (Probability of
Precipitation) look to vary between 10 and 20 percent across the
region over the next several days.

&&

.Marine...
Moderate to fresh trade winds will continue through Wednesday,
becoming gentle to moderate for the remainder of the week into the
weekend. Seas of 5 to 7 feet tonight will subside to between 4 and 6
feet by Wednesday morning. A small northeast swell will continue to
produce a moderate risk of rip currents along north facing reefs
through Wednesday night. This swell will move out of the region by
Thursday, allowing the rip risk to drop to low. The easterly trade-
wind swell is expected to maintain a moderate risk of rip currents
along east facing reefs for at least the next several days.

&&

.Fire weather...
Very dry conditions with moderate to fresh winds and strong gusts
continue across Guam this afternoon. The KBDI currently stands at
736. So far today, only a trace of rainfall was measured at the
airport and little or no additional rainfall is expected. The lack
of rainfall and low relative humidities along with moderate to fresh
winds will maintain a critical fire danger through Thursday.
Therefore, a Red Flag Warning remains in effect.

&&

.Eastern Micronesia...
A band of trade-wind convergence extends eastward from Majuro and is
slowly pushing into Kosrae this evening, generating scattered
showers and isolated thunderstorm. Pohnpei has experienced fairly
dry weather today but as the area of convergence near Kosrae pushes
westward, the potential for showers and thunderstorms will increase
after midnight. Models show this band of trade convergence weakening
Wednesday as it continues westward and leaves the support of eastward
moving upper-level trough that currently extends over the northern
Marshall islands and ends northwest of Kosrae. This would allow drier
weather to move into Pohnpei, Kosrae, and Majuro. However, there is
another band of trade-wind convergence that has slowly been entering
the region from across the Date Line, between 1N and 4N. This trade
convergence will increase the potential for showers and thunderstorms
across the region over the next few days, especially south of 7N,
providing little relief to drought conditions in the northern
Marshall islands, affecting islands such as Wotje and other nearby
islands/atolls.

Latest buoy and altimetry data show combined seas of 5 to 6 feet
near Pohnpei and Kosrae, and 6 to 7 feet near Majuro, driven by the
primary northeast to east swell, and a weak, secondary southeast
swell that originated in the southern hemisphere. This secondary
southeast swell is expected to slowly weaken over the next 24 hours
with the primary swell expected to briefly increase about a foot
over the next couple of days as the trade-winds remain around 15 to
20 kt, before both the northeast to east swell and trade-winds
subside slightly this weekend. Surf will be highest along east facing
reefs, but are expected to remain below hazardous levels, even at
Kosrae which has the lowest threshold of 8 feet along east facing
reefs.

&&

.Western Micronesia...
Himawari visible satellite imagery this afternoon reveals scattered
to numerous showers and isolated thunderstorms pushing westward
across Yap State toward the Republic of Palau. Showers are oriented
along a broad trade-wind trough located just west of Yap Proper,
extending south-southeast through where the trough intersects the
Near-Equatorial Trough (NET). Although most of the convection is
seen west and south moving away from Yap Proper, scattered showers
are seen around and north of the island, associated with trade-wind
convergence along the northern edge of the trough. Model guidance
favors numerous showers and isolated thunderstorms developing for
Palau after midnight tonight and tomorrow as the trade-wind trough
shifts westward, while maintaining scattered coverage for Yap with
convergence along the back side of the trough.

A weak circulation can be seen just southeast of Mindanao in the
visible satellite loop this afternoon, and the GFS wants to develop
another weak circulation or two over the next few days within the NET
southwest of the Republic of Palau. This could help bring heavy
moisture northward and maintain numerous showers near Palau for
another day or so, but without greater certainty, for now showers
were left at scattered for Thursday through the rest of the week. Yap
will remain on the northern edge of the deep moisture and associated
convection, and will likely experience more on-and-off scattered
showers over the next week or so, while Palau sees a more consistent
wet pattern through the forecast period.

To the east, Chuuk remains mostly dry for the next day or so with
showers increasing toward the end of the week as a trade-wind trough
pushes through the area, which could see enhancement from an upper-
level low developing just north of the region. The next trough looks
to cross the area this weekend, helping to maintain scattered
showers in the forecast into early next week.

Benign sea conditions will continue through the forecast period, with
latest altimetry showing 4 to 6 foot seas near Chuuk and 3 to 5 foot
seas just east of Palau. Overall, winds will be gentle to moderate
for Palau, becoming moderate to fresh at times in the second half of
the week, with stronger gusts possible near heavier showers for Palau
over the next few days. Yap will see moderate to fresh trades
through Wednesday before coming down to gentle to moderate for the
rest of the period. Chuuk will see moderate to fresh trades for much
of the remainder of the week, coming down to gentle to moderate this
weekend.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...Red Flag Warning until 4 PM ChST Thursday for GUZ001.

MP...None.
Marianas Waters...None.
&&

Marianas: Kleeschulte
East Micronesia: Schank
West Micronesia: Decou