812
FXPQ50 PGUM 062046
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
646 AM ChST Fri Jun 7 2024

.Marianas Synopsis...
Satellite shows partly cloudy skies and isolated showers moving
through the Marianas Waters this morning. Combined seas of 4 to 6
feet are composed mainly of trade-wind swell and wind waves.

&&

.Discussion...
The Tropical Upper Tropospheric Trough (TUTT) will remain the primary
influence on our weather through the next few days. We`re currently
in a portion of the TUTT with less upper-level divergence, so we`re
getting essentially dry season weather. The portion with more of that
upper-level divergence is not that far to the east though, with
scattered showers and isolated thunderstorms in abundance.

The higher shower activity could arrive sooner than expected. The
previous forecast had it coming in Wednesday, went ahead and bumped
that into Monday for now, and we`ll need to be watching that. Started
bringing in mention of thunder Sunday night, since the TUTT is our
most prolific producer of lightning and thunder here. The general
story is sound, it`s just the details, like mainly the timing, that
need to be worked out.

&&

.Marine...
Benign conditions are in place and will continue. Combined seas of 4
to 6 feet will diminish further to between 3 and 5 feet around
Saturday. East winds of 10 to 15 knots will diminish to between 5 and
10 knots around Saturday night. Just watch out for lightning starting
as early as Sunday night, and that will be your main weather related
hazard.

&&

.Eastern Micronesia...
Made some minor changes to the previous forecast to better match
trends noticed in satellite imagery overnight. The primary trend
noticed was cloud cover and showers diminishing overnight around
Pohnpei; so the forecast has been changed to have showers isolated
at Pohnpei this morning. Models still support weak convergence
developing across Pohnpei this afternoon, so kept scattered showers
for the afternoon but limited the chance of showers to 30 percent
through the weekend. Otherwise, the ITCZ has extended westward from
the central Pacific to south of Majuro as expected, and it is
currently east of Kosrae. The greatest potential for showers will be
around Majuro through the weekend as Kosrae will first remain on the
western edge of the ITCZ, and then as it starts to fragment and lift
northwestward this weekend, it will be south of the ITCZ, which
should allow showers to become isolated at Kosrae by Saturday.

Winds are mainly gentle to moderate across Pohnpei and Kosrae, and
are expected to become fresh at times at Majuro as due to the higher
showers and thunderstorm activity across the Marshall Islands.
Across the region seas are 4 to 6 feet, though seas may be slightly
choppier near the heavier convection across the Marshall Islands.
Seas are not expected to change much over the next several days.

&&

.Western Micronesia...
Across western Micronesia much of the convective activity has
diminished as the TUTT near Palau and Yap continues to weaken and
drift westward away from the islands, and the other TUTT near the
Marianas, has lifted slightly northward as well. With both TUTT cells
moving away from the region, this has reduced upper-level support to
any surface troughs moving through the region, reducing the overall
risk of widespread showers and thunderstorms. Winds will remain
light, especially around Palau, so the potential for island-effect
showers and thunderstorms at Palau during the afternoon hours remains
today and Saturday, especially if cloud cover decreases in the
morning and allows the sun to warm up the larger islands of Palau.
Given this restriction kept the chance for showers at 30 percent for
both today and Saturday. Minor trade-wind troughs moving through the
region are expected to bring some periods of scattered showers to
Chuuk later this weekend and then to Palau and Yap early next week.

Benign sea conditions and light and gentle winds are expected to
continue through early next week at Chuuk, Yap, and Palau. Altimetry
data near Chuuk and the buoys near Palau and Yap show combined seas
around 3 and 4 feet across the region this morning.

&&

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

$$

Marianas: Schank
Micronesia: Stanko