Area Forecast Discussion
Issued by NWS
FXPQ60 PGUM 252135
Area Forecast Discussion
National Weather Service Tiyan GU
714 AM ChST Tue Jul 26 2016
.Synopsis...East winds, scattered showers and isolated
thunderstorms prevail across the Marianas this morning.
A surface trough could be found on last nights surface analysis just
to the east of the Marianas. An upper-level low could be found north
of Saipan. The combination of the surface trough and upper low brought
scattered showers and isolated thunderstorms to the Marianas this
morning. Expect scattered showers and isolated thunderstorms through
the morning as the trough will move west and pass across the local
area. Showers will become isolated after noon, but enough instability
will remain to keep a chance of thunderstorms in the forecast
through the day.
Models show low-level convergence tonight through Wednesday night
plus another surface trough passing over the Marianas on Thursday.
Models depict shower coverage as patchy and while brief periods of
scattered showers are possible overall coverage should remain
isolated. Isolated thunderstorms are expected through Thursday
Ritidian, Ipan and Tanapag buoy data show combined seas of around
2 to 4 feet this morning. A east trade-wind swell will be present
through the forecast. Swell period was 12 seconds and WW3 model
does show this. Also Ritidian and Tanapag buoys still depicted a
small north swell. As no significant weather systems are expected
through the week which might increase winds or swell neither the
east swell nor the north will become too large. With winds staying
around 10 knots through the forecast, expect wind waves to remain
at around 2 feet through the week. Surf is predicted to be at 2 to
4 feet on east facing reefs and 1 to 2 feet on north, west, and
south facing reefs. The rip current risk will be low through the
Most showers and thunderstorms are west of Chuuk while showers
and thunderstorms across the northern RMI are associated with a
trade-wind trough that is moving toward Kwajalein this morning.
Scattered showers at Majuro early this morning should taper-off
and be mostly isolated today. Skies are partly cloudy at both
Pohnpei and Kosrae. Models suggest that most of the heavy showers
will tend to develop between 8N and 10N during the coming days,
but a wet trade-wind regime with some showers and thunderstorms at
times will continue from Chuuk across Pohnpei and Kosrae States
and the Marshall Islands through the next week or more.
Reasoning for the Chuuk forecast can be found in the Eastern
Micronesia discussion above.
Relatively wet weather will continue across far Western Micronesia
through this week. The disturbance centered roughly southeast of Yap
and Koror is poorly organized early this morning, but GFS Model has
been indicating it will move toward west-northwest and become better
organized in the coming days. Also, a surface trough from across the
Mariana Islands southward between Yap and Chuuk is producing showers
and a few thunderstorms as it moves westward. Slightly drier weather
is expected over the weekend, but low-level convergence will persist
and keep isolated thunderstorms in the area through the longer term.