617
FXPQ50 PGUM 210803
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
603 PM ChST Fri Jun 21 2024

.Marianas Synopsis...
Satellite imagery is showing partly cloudy skies and isolated showers
for Tinian and Saipan, with mostly cloudy skies and scattered showers
for Guam and Rota. A few lightning strikes have been observed south
and east of the Guam coastal waters. Latest altimetry passes and
Ritidian buoy are indicating combined seas of 3 to 5 feet in the
coastal waters.

&&

.Discussion...
A surface trough is clipping the southern Marianas through tomorrow as
it pushes west. Scattered showers for Guam and Rota tonight, but
should remain isolated for Tinian and Saipan. Some gusty winds
possible near heavier showers. A few lightning strikes and cloud
buildups have been observed to the south and east of the southern
coastal waters today and have included isolated thunderstorms for
Guam through tomorrow. A duo of trade troughs and a surge in trade
winds will result in an uptick in clouds and showers on Monday and
again on Wednesday. A few thunderstorms will be possible for Guam on
these days as well.

&&

.Marine/Surf...
Gentle to moderate winds expected through the weekend with combined
seas of 3 to 5 feet. Some fresh to strong gusts possible near heavier
showers in the Rota waters through tonight and Guam waters through
tomorrow. Winds increase to moderate to fresh and seas bump up to 5
to 7 feet beginning late Sunday night or Monday and continue through
at least the middle of next week as a surge in trade winds and trade
swell.

A moderate risk of rip currents will persist along east facing reefs
while remaining low along all other reefs. Surf looks to rise
beginning Sunday night and continue through the middle of next week
as the trade swell increases, with the rip risk possibly becoming
moderate along north facing reefs

&&

.Eastern Micronesia...
Satellite analysis during the day shows pockets of deep convection
along and north of the Inter-Tropical Convergence Zone (ITCZ). The
ITCZ stretches from the International Date Line westward south of
Majuro, then through Kosrae to just southeast of Pohnpei. Latest
deterministic and ensemble guidance from the ECMWF and GFS continues
to show the ITCZ fragmenting into individual trade-wind troughs this
weekend before dissipating early next week. Models keep a trade-wind
pattern in place through the middle of the week before the ITCZ
builds from the International Date Line westward across the region
toward the latter part of next week.

Gentle to moderate trades with benign seas are expected to persist
through the middle of next week at Majuro, Kosrae and Pohnpei. A
trade surge will move in from the east later this weekend, adding
around a foot to the seas. Altimetry passes this afternoon show
combined seas between 3 and 5 feet at Kosrae and Pohnpei, while
combined seas east of the Marshall are between 4 and 6 feet.

&&

.Western Micronesia...
A broad surface trough west of Chuuk and south of Guam is producing
pockets of moderate to deep convection along and ahead the trough
axis in eastern Yap State. Scattered showers over land and isolated
thunderstorms were observed over the coastal waters at Yap and
Palau. Model analysis continues to show the trough pushing over Yap
and Palau on Saturday into Sunday with scattered showers expected
due to convergence along the trough. A trough from eastern Micronesia
that was part of the fragmented ITCZ will push over Weno, and
generate shower activity Sunday into Monday. For the rest of next
week, weak trade-wind troughs will traverse over Chuuk, Yap, and
Palau, with bouts of showers expected to persist through the latter
part of next week.

Gentle to moderate trade winds and benign sea conditions are
expected to persist at Chuuk, Yap and Palau through the middle of
next week. Altimetry passes this afternoon show combined seas between
3 and 5 feet.

&&

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

&&

$$

Marianas: Slagle
Micronesia: Kelly