Strong Wind in Guam, February 8 to 9, 2023

Area Forecast Discussion
National Weather Service Tiyan GU
648 PM ChST Wed Feb 8 2023

.Marianas Synopsis...
Moderate to fresh winds prevail across the region, radar and
satellite imagery indicate isolated to scattered showers moving into
the region from the east. Buoy and altimetry data indicate seas are
between 6 and 8 feet.

&&

.Discussion...
Overall, little change in the forecast. The agitated cumulus field
approaching from the east will bring a brief uptick in showers
tonight and will gradually decrease back to isolated after midnight
tonight through the early morning hours tomorrow. Next in line is a
brief surge in the trades that is expected to produce breezy
conditions and another uptick in showers late Thursday night and
Friday. Otherwise, the lack of any robust features will make for a
fairly quiet forecast this weekend through early next week.

&&

.Marine/Surf...
Moderate to fresh trade winds become fresh to strong starting
Thursday night due to a surge within the trade flow. Combined seas
of 6 to 8 feet will build an additional one to two feet over the next
several days as trade swell rebuilds starting tomorrow and longer-
period north swell enters the region. As a result, a Small Craft
Advisory was issued this afternoon and will take effect starting
Thursday night through Friday night. Other than that, the only
coastal hazard we continue to expect is the high risk of rip currents
through Sunday night along east-facing reefs.

&&

.Eastern Micronesia...
A robust trade-wind surge continues across the region with the
showers and thunderstorms found along its southern edge, roughly
along 5-6N. Heavier showers have stayed offshore Pohnpei and Kosrae
while shorter-lived showers have continued to blow through the RMI
today, bringing occasional gusts to 35 kt. Notably, the Majuro
sounding indicated 46 kt winds at 3 kft and Kwajalein observations
have reflected persistent gusts of 25-30 kt today. This active
pattern will persist the next few days with models showing showers
lifting farther north to Pohnpei through Friday before backing
eastward toward Kosrae over the weekend. This backing trend seems
partly anchored to upper-level dynamics related to a southward-
dropping upper-level trough over the weekend. Trade winds will be
quite strong, especially across the RMI and north of Kosrae where
gusts will reach to around 35 kt. The latest forecast for rainfall
blends the GFS, ECMWF, and GEFS in the short term, then aligns with
the GEFS for a broader focus on the trends of winds and rains.

Have issued a new high surf advy for Majuro based on latest
altimetry data showing combined seas of 10-13 ft, which exceed
latest model data by 1-2 ft. Being generally all ENE trade swell,
this supports surf of 10-13 ft. Have also increased winds and seas,
as noted in the Majuro SCA. SCA and HSA considerations at Pohnpei
and Kosrae remain unchanged with the overall trend in seas and winds
gradually decreasing over the weekend.

&&

.Western Micronesia...
Widespread showers and a few thunderstorms continue along the near-
equatorial trough axis well south of Palau leaving dry conditions
across Yap and Palau. Farther east, heavier showers and
thunderstorms continue to slide south of Chuuk along the trade-wind
convergence axis focused along 4-6N. Model guidance shows the broad
band of showers over Eastern Micronesia lifting WNW the next couple
of days, bringing locally heavy showers to Chuuk by Thursday or
Thursday night with wet weather lingering into the weekend. This
wave of activity will continue west toward Yap and Palau, eventually
bringing gusty showers and thunderstorms to both locations Saturday
or Saturday night as a broad circulation tries to take shape along 3-
4N. Though a fairly typical weather progression for this time of
year, this feature will result in quite a wet weekend and start to
the next week with the possibility of gusts to around 30 kt. Have
held off on the inclusion of locally-heavy shower wording in the
forecast, though high certainty rests on the likelihood of a wet
forecast based on deterministic and ensemble models.

Concerning marine conditions, Chuuk remains with a SCA through
Thursday afternoon, but seas and winds look to diminish during the
day. Elsewhere across the region, moderate to fresh trades and seas
of 6-9 feet will continue into the weekend.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...High Rip Current Risk through late Sunday night for GUZ001.

MP...High Rip Current Risk through late Sunday night for MPZ001>003.

Marianas Waters...None.
&&

Marianas: Cruz
Micronesia: Aydlett