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FXPQ50 PGUM 240302 AAA
AFDGUM

Area Forecast Discussion...UPDATED
National Weather Service Tiyan GU
102 PM ChST Fri May 24 2024

.Update...
Showers associated with a passing trough remain over Guam and Rota as
the trough moves through the region slower than expected. Showers are
expected to become isolated later this afternoon or early evening.

&&

.Prev discussion... /issued 614 AM ChST Fri May 24 2024/

Marianas Synopsis...
Invest 93W has been downgraded from a Tropical Cyclone Formation
Alert (TCFA) to a Medium potential for development, and is just west
of 6N130E.

ASCAT Analysis indicates a weak trade-wind trough has been moving
across the Marianas overnight. Satellite shows a fairly heavy shower
to the northwest of Guam, otherwise patchy cloudiness is over the
region, and a few moderate to heavy showers were just southwest of
Guam Coastal Waters. Local airports report gentle to moderate trade
winds and combined seas are running 5 to 7 feet.

Discussion...
Overnight there has been patchy showers near and around the surface
trough as it has been moving slowly toward the west. Partly sunny
skies and showers becoming isolated are expected to develop today,
and then a relatively dry trade-wind pattern is expected thru most of
next week.

Marine/Surf...
Moderate winds and combined seas of 5 to 7 feet today will become
gentle to moderate winds and seas of 4 to 6 feet this weekend. Some
of the showers and very isolated thunderstorms south of Guam could
affect the southern waters of Guam. There is a moderate risk of rip
currents along north and east facing reefs, while a low risk prevails
for south and west facing reefs. Surf is expected to fall another 1
to 2 feet along north and east facing reefs this weekend. This should
cause the risk of rip currents to become low along north facing
reefs, but likely remain moderate along the east.

Fire weather...
Rainfall yesterday at Guam airport was 0.05 inch, and the KBDI is up
to 593 today, in the high category. The trade-wind flow will become
relatively dry and only passing showers are expected in the coming
days. Winds could be gusty in the mountains during afternoon hours,
but the wildfire threat will likely remain below Red Flag criteria.

Tropical systems...
Invest 93W has been downgraded to Medium chance of development and
has moved farther west of Koror and is centered just west of 6N130E
early this morning. It is expected to move toward the northwest and
gradually curve northward. Still, there are large areas of showers
over Western Micronesia this morning that will affect Yap State and
The Republic of Palau for the next day or two anyway.

Eastern Micronesia...
A long trough has set up in the central and easter portion of eastern
Micronesia. The southern most tip of this trough`s axis is due south
of Kosrae. The most northern tip crosses the dateline at about 12N.
The angle of this trough takes the axis right through Majuro. The
Atolls of Majuro, Ailinglaplap, Jaluit, Namorik, Ebon, Mili, Arno
and the island of Kosrae will be experiencing this trough today and
the island of Pohnpei can expect to see it tonight into early
tomorrow morning. Showers are expected to be isolated today building
in to scattered for tonight and through the weekend. This trough is
expected to be the forerunner of a strengthening Inter-Tropical
Convergence Zone (ITCZ) that will makes its presence known early next
week.

Benign marine conditions are expected over the next several days.
Moderate trade winds become gentle to moderate this weekend.
Altimetry shows combined seas through the RMI at 3 to 4 feet and
near Pohnpei as 5 to 6 feet.

Western Micronesia...
There are three dense spotty convection clusters of note in western
Micronesia. The first near the island group of Sonsorol in southern
Republic of Palau, the second south of Yap proper and east of Koror
Palau, and the third in western Yap state. The first cluster is
producing some lightning and cloud tops of the biggest cell is
reaching in the -80s, some heavy downpours are possible. This cluster
is expected to pass Sonsorol over the next day or two. The second
cluster is moving into Yap Proper`s waters as of this writing. This
system will bring much needed rain to the parched island of Yap
Proper. The showers and thunderstorms are expected to remain through
the weekend. The last cluster is a tad bit different, the first two
are remains of 93W, while this one is the effects a robust trough.
This trough is located near the Atolls of Gaferut, Faraulep, Ifalik,
Satawal, and Eauripik. This cluster of showers are the least
convectively active, cloud tops are reaching in to the -60s with a
few cells over achieving, however, not much in the way of lightning
is happening. Still showers may be heavy at times in this region.

Chuuk, on the other hand, can expect fair weather today before
the showers to the north and east come. These incoming showers are
anticipated to build through the weekend and well into the middle of
next week.

Seas are beginning to subside since 93W has moved farther away.
Latest Altimetry shows 5 to 7 feet east of Chuuk, between Chuuk and
Yap 5 to 6 feet and east of Palau 3 to 5 feet. Winds are expected to
be gentle to moderate with stronger winds near the larger convective
cells.

&&

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

$$

Update: Kleeschulte
Marianas: Simpson
Micronesia: Bowsher