Area Forecast Discussion
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FXPQ60 PGUM 262135

Area Forecast Discussion
National Weather Service Tiyan GU
724 AM ChST Thu Jul 27 2017

.Marianas Synopsis...Southwest winds and isolated showers prevail
over the Marianas this morning.


.Discussion...Little change made to forecast. Did update winds with
new model data but nothing else.

Observations from the Marianas showed winds to be light and variable.
Radar VAD wind profile indicated winds at 2000 ft from the southwest
at around 5 mph. Sounding data from last night showed that moisture
increased slightly from yesterday afternoon to last night. The light
winds and available moisture produced afternoon scattered showers
across the islands of the Marianas on Wednesday, and since conditions
are similar expect afternoon scattered showers across the islands

Light southwest winds will continue for at least the next ten days.
Models show deep layer moisture decreasing Friday reaming low through
at least Sunday so only expect isolated showers, even during the
afternoon hours this weekend.


Observations this morning from Ritidian, Tanapag, and Ipan buoys
indicate combined sea heights around 2 to 4 feet. Models show a few
five foot seas are possible. Expect sea heights of 3 to 5 feet
through Friday night. A slight increase in winds will bump the seas
up to 4 to 6 feet Saturday.

The buoys still show a northeast swell and a southwest swell. The
southwest swell has picked up enough to generate surf of 3 to 5 feet
on west facing reefs. Surf of that height produces a chance of
moderate rip currents.

Even though Typhoon Noru will remain north of 20 north through the
forecast, it will gain strength. As a strong storm it will generate
ocean swells and some of those will head towards the local area.
The swells from the typhoon may start to enter the Marianas by the
beginning of next week. This swell will increase surf on north facing
exposures. The southwest swell will gradually turn to the west.

The swell from the typhoon may become large enough to generate
hazardous surf on north facing reefs by Monday night.


.Eastern Micronesia...
Much drier weather wedged in over the Marshall Islands overnight
as the area of trade wind showers and thunderstorms shifted west.
This area is now near and south of Kosrae to near Pohnpei. IR
satellite shows scattered showers and isolated thunderstorms near
both locations this morning and will continue through this
afternoon at Pohnpei, and Friday at Kosrae. GFS model sticks with
a predominant trade-wind pattern the next few days with no major
weather features depicted in the region through Monday other than
isolated showers at all locations and isolated thunderstorms for
the weekend.


.Western Micronesia...
A weak tropical disturbance southwest of Chuuk continues its slow
trek westward. IR satellite shows quiet conditions and light/variable
winds over Weno and much of Chuuk State. Showers and thunderstorms
are currently near and west of Woleai, and well south of Weno near
the equator.  Light south to southeast winds and a relatively quiet
weather pattern is expected the next few days.

A weak area of high pressure sits just east of Koror and south of Yap.
Southwest monsoon flow is west of Yap and Koror while showers and
thunderstorms near a disturbance between Yap and Chuuk approaches from
the east. A benign weather pattern will be in place the next few days
characterized by a weak monsoon flow with gentle south to southwest
winds and isolated showers. There will be a slight chance of
thunderstorms through the weekend for both locations.


Marianas Waters...None.


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