588
FXPQ50 PGUM 070815
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
615 PM ChST Tue May 7 2024

.Marianas Synopsis...
Partly cloudy skies with spotty showers and mostly gentle trade winds
prevail across the Marianas this evening. Altimetry shows seas
between 5 and 7 feet.

&&

.Discussion...
The dry pattern continues over the Marianas through Wednesday. By
Wednesday evening, a decaying shear line fragment looks to move into
the Marianas at around the same time that a trade-wind trough moves
through. This is expected to bring low-end scattered showers to the
Marianas for a short time Wednesday night. By Thursday, the dry
pattern returns and looks to continue through the coming weekend.

A Near-Equatorial Trough (NET) remains to the south of the Marianas,
south of Yap and Palau. This feature has a couple of weak
disturbances embedded along it, Invest 90W and 91W. For more
information on the invests, see the Tropical systems section, below.
Models are showing these circulations drifting a bit north, pulling
the NET with them. This is expected to bring increased instability
over the Marianas over the weekend, around 24 hours later than the
previous forecast and model runs were predicting. Therefore, expect a
slight chance of thunderstorms across the region Saturday through
the beginning of next week. Guam and Rota look to be most likely for
this convection. If a stronger system does develop over the weekend,
shower coverage may need to be increased.

&&

.Marine...
Combined seas of 5 to 7 feet are expected to begin to subside
Wednesday morning, dropping to between 3 and 5 feet by the end of the
week. Seas are then expected to build slightly over the weekend, with
seas increasing to the 4 to 6 foot range. Mostly gentle winds tonight
will slowly increase over the next few days, becoming mostly moderate
for the weekend.

&&

.Tropical systems...
The Joint Typhoon Warning Center is maintaining 2 areas of interest
across Micronesia associated with the NET, this evening. The NET
stretches eastward across 130E near 5N to Invest 91W, centered near
4n130e. The NET continues eastward to Invest 90W, centered near
9n142e, then turns southeast to end at the equator near 155E. Both
Invests remain sub-low, meaning no development is expected over the
next day or so. Latest model guidance continues to push weak
circulations westward along the NET, with the GFS and some of the
GEFS and ECMWF Ensemble members developing a Tropical Disturbance or
Storm across western Micronesia over the weekend. Confidence in the
occurring is extremely low at this time, with the most likely
scenario being several weak disturbances developing and moving
westward along the NET. Residents of Palau and western Yap State
should continue to monitor forecasts and discussions for any
changes to the expected conditions.

&&

.Eastern Micronesia...
Trade-wind convergence along two surface troughs in the region is
producing scattered showers and isolated thunderstorms east of Majuro
and over and south of Pohnpei. Both deterministic and ensemble GFS
and ECMWF shows trade convergence lifting north in response to the
Near-Equatorial Trough in western Micronesia through at least this
weekend. Periods of scattered showers and isolated thunderstorms are
expected through the period with weak trade troughs that traverse
within the trade convergence over Majuro, Pohnpei, and Kosrae
through early next week.

Gentle to moderate trades and combined seas of 5 to 7 feet are
expected through at least the weekend at Majuro, Kosrae, and Pohnpei.

&&

.Western Micronesia...
A surface trough is moving over Weno this afternoon and producing
numerous showers and isolated thunderstorms over Chuuk State.
Scattered showers and isolated thunderstorms are ongoing along and
north of the Near-Equatorial Trough (NET) located over extreme
southern portion of the Republic of Palau. Latest model guidance
shows the NET will slowly lifting northward by the embedded weak
circulations along the trough to just south of Angaur will lead to
elevated chances for showers and thunderstorms at Yap and Palau.
Models vary greatly on strength and location of aforementioned
circulations along the trough. For more information on these
circulations, please see the Tropical systems section above. For
Chuuk, trade-wind troughs impinging into the NET will generate
chances for scattered showers and isolated thunderstorms through at
least the weekend.

Gentle to moderate trades and combined seas of 4 to 6 feet are
expected at Yap and Palau through the weekend. For Chuuk, gentle to
moderate trades with some gusts to fresh through Wednesday evening
are expected, then gentle to moderate trades are expected through the
weekend.

&&

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

$$

Marianas: Kleeschulte
Micronesia: Kelly