Area Forecast Discussion
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FXPQ60 PGUM 250734
AFDPQ

Area Forecast Discussion
National Weather Service Tiyan GU
534 PM ChST Sun Jun 25 2017

.Marianas Synopsis...
A developing tropical disturbance is moving through the Marianas
tonight. Another upper-level low is seen well to the east near
Wake Island. The buoys reveal combined seas of 5 to 7 feet near
Guam. Scatterometer data shows winds of 20 to 25 knots in the
Northern Marianas waters with lighter winds in the Guam waters.

&&

.Discussion...
All eyes are on the tropical disturbance at this time. It should
be passed through and gone by Tuesday though. For tonight, Rota,
Tinian and Saipan will be breezy, and all will receive numerous
locally heavy showers as it passes through. The convection is
still very much cycling and is currently in a down swing, this
will not last though. After the disturbance passes, a return to
fair weather is in the cards for a day or two, then an upper-level
low currently near Wake will affect the Marianas, bringing the
thunderstorms back to the forecast.

&&

.Marine...
Needed to issue a small craft advisory for Rota, Tinian and
Saipan based on scatterometer data. Since the strongest winds are
north of the center of this disturbance, left Guam out of it at
this time. Made it just for winds as the waves are expected to
fall short. They have been low and will not have sufficient time
to build in this newly better environment. After tonight the winds
are expected to subside so this will be a short lived event.

&&

.Tropical systems...
A developing tropical disturbance near the Marianas is now the
subject of a Tropical Cyclone Formation Alert from the Joint
Typhoon Warning Center. It is not a Tropical Depression yet, so
there is no official number, just lots of rain and lightning with
some gusty winds. Watch for further bulletins from the National
Weather Service Guam on this system.

&&

.Eastern Micronesia...
A pattern of converging winds and areas of widespread showers
remain across the area from near and south of Chuuk to east of the
date line. Heaviest showers have been near Kosrae, Majuro and
Kwajalein today, but will quickly build in at Pohnpei late this
afternoon into the early evening hours. Gusty northeast winds
could accompany the leading edge of showers there. This broad belt
of showers and thunderstorms will continue slowly west-northwest.
Relatively drier weather will build in by mid-week, but model
guidance indicates another area of trade-wind convergence and
patchy showers will move from across the Date Line into Eastern
Micronesia later in the week.

&&

.Western Micronesia...
ASCAT and satellite imagery shows a very dry/light wind regime in
place at Yap and Koror this afternoon. Dry weather will dominate
the next couple days while Tropical Disturbance 97W in the
Marianas will soon maintain a light and variable/southwest wind
flow over both locations. Weather conditions could become
unstable over the area later in the week as a weak trade wind
disturbance approaches from the east.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...None.
Marianas Waters...Small Craft Advisory for winds until 6 AM CHST Monday for
     PMZ152>154.

&&

$$

Stanko/M. Aydlett



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