Rip Current in Guam, April 24, 2021

Area Forecast Discussion
National Weather Service Tiyan GU
813 PM ChST Fri Apr 23 2021

.Marianas Synopsis...
Southwest winds prevail over the Marianas this afternoon. Satellite
imagery shows only a few clouds and showers over the area. A
stationary front could be found just north of Saipan.

.Discussion...
A few small changes made to the current forecast. A stationary front
could be found just north of Saipan. Models keep it north of Saipan
although they show a few showers just south of the front passing over
Tinian and Saipan. This highest chance is expected to be after
midnight through early morning Saturday. Have scattered showers over
those two locations but thunder is not expected. Over Guam and Rota
only a few isolated showers are expected. The remainder of the
weekend will be tranquil with only partly cloudy skies and isolated
showers expected. Typhoon Surigae, well over 1000 miles to the
northwest of the Marianas will move northeastward and pass north of
the local area by Monday. The typhoon, or what is left of it, as it
begins to weaken will have no direct effects on the Marianas. It will
drag a surface trough across the Marianas Monday. The trough will
bring scattered showers and isolated thunderstorms to the local area
Monday through Tuesday. South to southwest winds will prevail ahead
of the trough and during the troughs passage. Winds will become
variable Tuesday night with east trade-winds returning by
Wednesday. Convergence associated with the returning trade-winds will
bring a second round of scattered showers and isolated thunderstorms
Wednesday and Wednesday night.

&&

.Marine/Surf...
Ritidian and Tanapag buoys showed seas between 5 to 6 feet. Models
depict seas around 5 feet tonight increasing slightly by Saturday
night. Both buoys had a northeast and a west swell. The west swell
will become northwest by Monday. The northwest swell, which was
generated by Typhoon Surigae will gradually build and is expected
to bring increasing surf on west and north facing reefs. The swell is
predicted to generate hazardous surf on north and west facing reefs
starting Sunday night or Monday. The swell will begin to lower and
so will the surf, decreasing below hazardous level by mid-week.

&&
.Fire weather...
The KDBI has increased to 727 today. A wetting rain is not expected
until Monday. Winds are expected to remain below Fire Advisory
criteria although dry conditions will be favorable for spot fires.
A few of these spot fires was observed during the morning and
afternoon on Friday.

&&
.Tropical systems...
Typhoon Suriage was located over 1000 miles to the west-northwest of
the local area. Suriage is still a typhoon but is continuing to
weaken and should be a tropical storm by Saturday morning. It will
eventually become extra-tropical by late Saturday and Sunday. Suriage
or what is left of it will move north of the Maraians and north of
20 north. Even through it is weakening it still will be associated
with stronger winds. Current models keep the strong winds north of
Saipan with winds between 20 to 30 mph briefly possible over the
islands of the extreme northern CNMI.

&&

.Eastern Micronesia...
Dry conditions and gentle trade winds are seen across the Marshalls
with a ridge of high pressure that stretches westward towards Kosrae
and Pohnpei with more southerly flow. Subtle areas of low-level
convergence are generating scattered showers around Kosrae and
northwest of Pohnpei.

Majuro will see dry conditions gradually erode late tonight and
first part of Saturday as a trade disturbance, currently near the
dateline, approaches. The brunt of this trade disturbance will pass
by to the south of Majuro so maintained isolated showers. However,
seeing some support for a period of scattered showers Saturday
evening into early Sunday from both GFS and ECMWF. Expect the weak
low-level convergence around Kosrae to wash out tonight with drier
trade flow returning for the weekend. Convergent trade flow should
bring an increase in showers to Kosrae early next week, possibly
lingering through the week. Models suggest the batch of convergent
flow northwest of Pohnpei will drift over Pohnpei Saturday afternoon
as it begins to wash out. Kept the possibility of thunderstorms for
Saturday at Pohnpei due to light winds, ample moisture and island
heating. Maintained a drier outlook for early next week but seeing
some support for a bit of an uptick in trade showers.

Combined seas will bounce between 3 to 5 feet the next few days
before increasing next week in response to building trade winds and
longer period north swell. Surf may become hazardous along north
facing reefs of Pohnpei and Kosrae Monday as a NNW builds.

&&

.Western Micronesia...
Dry conditions are in place at Palau and Yap with light south to
southwest flow. Meanwhile, showers and thunderstorms are flaring up
across Chuuk lagoon as a surface trough with an embedded
circulation sits overhead and links up with upper-level divergence.

Palau and Yap: Continued dry weather is expected for Palau and Yap
through Saturday night as a gentle southwest flow establishes. GFS
and ECMWF suggest a weak monsoon tail will drape over Palau and Yap
Sunday and Monday. This feature will be the best opportunity for
showery weather before a more stable trade-wind pattern returns
around the middle of next week. Combined seas of 5 ft will climb
another foot or so Sunday/Monday as another pulse of NW to N swell
filters in. Surf could become hazardous for reefs that favor a
northerly direction swell, especially for Yap.

Chuuk: Showery weather with the trough/circulation looks to linger
through tonight and possibly Saturday. Seeing some support for
scattered showers starting Monday as convergent trade flow sets up
near Chuuk based on GFS and ECMWF. Expect gentle south to southeast
winds until moderate trade winds return on Tuesday. Combined seas of
4 ft will edge upwards to 6 feet early next week as longer period
north swell fills in.

&&

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

Marianas: Ziobro
Micronesia: Bukunt