849
FXPQ50 PGUM 122042
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
642 AM ChST Mon May 13 2024

.Marianas Synopsis...
Satellite imagery this morning shows partly cloudy skies and spotty
showers across Guam, Rota, Tinian, and Saipan. Winds are gentle to
moderate, with combined seas around 4 to 6 feet.

&&

.Discussion...
The forecast continues to change very little. A dry trade-wind
pattern is expected to continue into the weekend. There is a weak
trade-wind trough passing through the far northern Mariana Islands,
while Saipan to Guam is expected to remain partly cloudy today with
only isolated showers. Though additional trade-wind troughs are
expected to move across the Marianas over the next several days,
model keep shower activity isolated with POPs (Probability of
Precipitation) remaining around 20 percent.

&&

.Marine...
Gentle to moderate trade winds and combined seas of 4 to 6 feet will
continue through Tuesday night. Then, winds look to become mostly
moderate and seas are expected to build to between 5 and 7 feet
around Wednesday.

&&

.Fire weather...
The potential for a wetting rain is unlikely over the coming days,
with only isolated trade showers expected. This will allow the KBDI
to continue to rise, and should exceed 500 Tuesday and enter the
high category. Winds so far at the RAWS (weather station) near
Dandan, have been peaking at around 15 mph, with relative humidity
around 60 percent or higher, helping to limit the risk of rapidly
spreading fires. These conditions will continue through the week, so
neither a Fire Weather Watch nor Red Flag Warning are anticipated
through the week.


&&

.Eastern Micronesia...
Overall activity across the region has diminished overnight. The
circulation that was over the southern Marshalls has weakened further
and opened up into a trough and the cluster of thunderstorms
northwest of Pohnpei has stratified out. Meanwhile, an area of
diffluent flow continues to suppress showers over Kosrae. Model
guidance indicates patchy showers hanging around Pohnpei and
remaining scattered at Majuro today. The trough near the Marshalls
is expected to drift westward, bringing scattered showers to Kosrae
late tonight. Around midweek, trade convergence is projected to
rebuild across the region, maintaining periods of scattered showers
and isolated thunderstorms for Pohnpei, Kosrae, and Majuro. A couple
of disturbances may develop farther west and in the southern
hemisphere; this, in turn, may downgrade trade convergence once again
late week and over the weekend.

Gentle to moderate trades and combined seas of 5 to 7 feet are
expected through the week. Around midweek, models hint at a weak
south-southeast swell entering the region, however no significant
impacts are expected at this time.

&&

.Western Micronesia...
A Near-Equatorial Trough (NET) remains anchored across the
southernmost part of the region, passing through a couple of very
weak circulations roughly centered at 1N144E and 3N155E. As the week
progresses, model guidance depicts the two embedded circulations
gradually merging into a broader vorticity feature near eastern Yap
State. However, model consensus wanes by the weekend and the GFS
shows a robust circulation detaching from the NET, wandering off to
the northeast over Chuuk. As of now, this is regarded as an outlier
and will need to be monitored in subsequent model runs. Overall, a
trend towards wetter weather is in store for Chuuk and eastern Yap
State, whereas the main islands of Yap and Palau should see drier
conditions over the next few days, being northwest of the
disturbance. Showers have a chance to build in late week, depending
how this system evolves.

Combined seas of 3 to 5 around Yap and Palau and up to 6 feet closer
to Chuuk are expected over the next several days. Gentle to moderate
trade winds become light to gentle starting tonight for Palau,
Wednesday for Yap, and Thursday for Chuuk. For now, relying mostly
on ensemble model winds since the GFS is spinning up a stronger
system in the recent run.

&&

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

$$

Marianas: Schank
Micronesia: Cruz