Area Forecast Discussion
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FXPQ60 PGUM 212102

Area Forecast Discussion
National Weather Service Tiyan GU
700 AM ChST Wed Nov 22 2017

.Marianas Synopsis...
East trade-winds and isolated showers prevail across the
Marianas this morning.


Little change made to the forecast. A series of high pressure areas
will move off of Asia through the coming week. The pressure gradient
between high pressure and lower pressure south of 10N will produce
east to northeast trade-winds of mainly between 10 to 20 mph through
the forecast. A slightly stronger center of high pressure will
help generate winds of 20 to 30 mph Saturday through Monday.

Deep-layer moisture will vary over the course of the forecast and
there could be some patchy clouds at times, although partly cloudy
skies will be the predominant type. Showers will be isolated at best.


Ipan...Tanapag and Ritidian buoys show sea heights near 5 to 8 feet.
Satellite altimetry data also shows 6 foot seas over the local area.
Tanapag and Ritidian show a northwest swell and a northeast swell.
The northeast swell will persist through the forecast. The northwest
one will last through Saturday night.

As mentioned above...winds will increase over the weekend and most
likely will reach Small Craft Criteria. Sea heights will also
increase enough that Small Craft Advisory conditions of 10 feet are
possible for part of the weekend. This increase in sea heights
and wind waves combined with a slight increase in swell heights
may also generate hazardous surf conditions on north and east
facing reefs this Saturday through early next week.


.Eastern Micronesia and Chuuk...
A weak circulation continues to slowly move across Micronesia. It
is now located to the south of Chuuk near 3N152E. A near-
equatorial trough stretches eastward from the circulation to end
near EQ152e. Convergence north of the circulation and trough
continues to ignite scattered showers and isolated thunderstorms
mainly north of Chuuk. Isolated showers and a few thunderstorms
will continue to affect Chuuk today as the system continues to
slowly drift westward. The convection is now developing near the
northern Pohnpei waters as well, resulting in isolated
thunderstorms remaining in the Pohnpei forecast. Drier conditions
are now in place over Kosrae as the system has pulled farther
west. Isolated trade-wind showers will prevail from Kosrae to
Majuro. By the end of the week, these drier conditions will move
in to Pohnpei as well and finally to Chuuk for the weekend. A
surface trough, currently east of the date line, is expected to
approach the Marshalls by the weekend, bringing an increase in
convection to Majuro.ough may bring more showers to Majuro and
Kosrae by the weekend.


.Western Micronesia...
The models continue to show the circulation, currently south of
Chuuk, weakening as it approaches Yap and Palau. A surface trough
extends eastward through 2N130E to the circulation. An unsettled
pattern is expected to continue along this boundary over the next
few days with most of the convection remaining south of Yap, but
close enough to bring isolated thunderstorms to the area Thursday
evening and Friday. Scattered showers are likely at Koror for the
end of the week into the weekend.

Although models tend to weaken this circulation, will continue to
monitor the system for any unexpected strengthening.

Marianas Waters...None.


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