464
FXPQ50 PGUM 100805
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
605 PM ChST Mon Jun 10 2024

.Marianas Synopsis...
Partly cloudy skies and isolated showers with gentle to moderate
trades were seen across the region. The Ritidian buoy shows seas
between 4 and 5 feet.

&&

.Discussion...
Scattered showers southeast of the Marianas will move into the area
later this evening. Models show an increase in shower activity as
deeper moisture shown on the CIMSS MIMIC precipitable H20 with
values between 2.50 and 2.95 inches moving over the region. The
deeper moisture will interact with convergence and a series of weak
trade-wind troughs through the middle of the week. For the latter
part of the week, both the ECMWF and GFS show a TUTT (Tropical
Upper-Tropospheric Trough) cell at approximately 23N157E moving
west-southwestward through the region around Friday. The combination
of ample moisture along with elevated omega values shown in
time/height analysis suggests that will be enough instability in
place for thunderstorms across the region on Thursday and Friday. The
TUTT cell is then expected to move away from the region during the
weekend with a trade-wind pattern returning, resulting in only
isolated showers through early next week.

&&

.Marine...
Gentle to moderate trades and combined seas of 3 to 5 feet are
expected through Thursday, before trade swell and wind waves
strengthen, adding a foot or two to seas toward the latter part of
the week.

&&

.Eastern Micronesia...
A dry trade-wind pattern is now in place across eastern Micronesia.
This looks to change over the next couple of days. A trade-wind
trough that has moved in from east of the Date Line will approach
Majuro Tuesday morning, bringing increased showers to the atoll.
This trough is the first in a series of troughs that are expected to
move across the Date Line. The first trough is then expected to reach
Kosrae Tuesday night and Pohnpei Wednesday afternoon or evening.
POPs (Probability of Precipitation) look to be around 30 percent
through Thursday. To the east of the Date Line, the latest satellite
and ASCAT data show an active Inter-Tropical Convergence Zone (ITCZ)
stretching eastward from near 175W. Latest model guidance shows this
feature developing westward over eastern Micronesia. As the troughs
interact with the developing ITCZ, expect an increase in instability
bringing a slight chance of thunderstorms to the region beginning
around Thursday.

Other than the showers and thunderstorms, marine conditions look to
remain fairly benign. Combined seas will remain at or below 6 feet,
with mostly gentle to moderate trade winds expected through the week.
Occasional fresh winds are possible at Pohnpei around midweek.

&&

.Western Micronesia...
Isolated showers are seen over Yap and Palau as a disturbance
approaches from the east. A slight uptick in showers is expected for
Yap tonight from passing showers. A disturbance in the vicinity of
Eauripik is expected to arrive Yap and Palau late Tuesday and bring
scattered showers, most likely on and off scattered showers. Did
decrease the POPs for Koror to 30 percent for the mid week forecast
period due to models showing a few trade wind troughs passing through
Yap and Palau, but nothing major as far as precip amounts. Also
expecting some southeasterly flow for Yap and Palau mid week. Late
week through the weekend looks like a weak ITCZ develops near Chuuk
and makes its way to Yap and Palau, possibly bringing increasing
scattered showers to Chuuk around Friday and to Yap and Koror around
Monday.

Latest altimetry observed combined seas of 2 to 4 feet near Yap`s
waters, and buoys reported the same. Light winds are expected to
remain over Koror through most of the week, and light to gentle for
Yap. Gentle to moderate winds are expected for Chuuk around mid week.

&&

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

$$

Marianas: Kelly
Eastern Micronesia: Kleeschulte
Western Micronesia: Hong