Area Forecast Discussion
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FXPQ60 PGUM 232124

Area Forecast Discussion
National Weather Service Tiyan GU
638 AM ChST Fri Nov 24 2017

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


Little change made to the forecast. Did update winds with new model
data. An area of high pressure is now moving off of Asia and will
move across the Western North Pacific the next several days. The
pressure gradient between this high pressure and lower pressure south
of 10N will produce breezy east to northeast winds of between 10 to
25 mph through the weekend.

Deep-layer moisture will be low this weekend and skies will be partly
cloudy. Trade-wind convergence will increase the moisture with mostly
cloudy skies prevailing for at least the first half of the coming


Ipan...Tanapag and Ritidian buoys show sea heights between 6 and 7
feet. Satellite altimetry data also shows 6 to 7 foot seas over the
local area. Tanapag and Ritidian show just a northeast swell. Model
data keeps a northerly swell over the area and there is a faint hint
of it in the Ritidian buoy data. The northeast swell will persist
through the forecast. Model data keep the north swell through
Saturday night. It will briefly be replaced by a northwest swell that
will occur Sunday through Monday.

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 by
Sunday and continuing through early next week.


.Eastern Micronesia...
A few showers and thunderstorms persist just south of Pohnpei and
east of Majuro, but dry weather is otherwise seen across the area.
While fairly dry weather is expected to continue for the region,
isolated thunderstorms will move into Majuro waters later today.
Showers will increase over the weekend. Increasing trade-wind
convergence will maintain wet conditions there into early next week,
while also bringing wetter weather to Kosrae and Pohnpei around

Winds and seas will rise in the Marshalls late in the weekend and
early next week, and could approach levels hazardous to small craft
operations and produce hazardous surf conditions. Seas, winds and
surf will also build some at Pohnpei and Kosrae.


.Western Micronesia...
Overnight surface analysis indicated a weak circulation south of
Koror near 4N134E with a trough extending to the west and the
northeast. Little convection is seen near these features, but a thick
band of showers and thunderstorms has persisted within convergent
trade-wind flow to the north. Scattered showers and isolated
thunderstorms east of Koror will move into the area later this
morning and continue through Saturday night. Yap is just on the
northern edge of convection so have gone with a split forecast for
today with heavier showers and thunderstorms over the southern waters
with slightly drier conditions north of Yap. Increasing northeast
trades are expected to push convection southwest this evening. Drier
weather is expected for both Yap and Koror later in the weekend.

At Chuuk, showers and thunderstorms will slowly shift to the west and
southwest this afternoon and evening. A drier trade-wind pattern will
dominate through the weekend with a few more clouds and showers
expected by Tuesday.

Fresh to strong trade winds at Yap will be hazardous to small craft
operations the next few days. In addition, winds at Koror will
increase to near advisory levels the next few days. Seas are
currently forecast to stay below small craft criteria at all three
forecast points for now, however, seas will be monitored for possible
small craft criteria over the next couple of days. Surf along north
and east shores will also rise and could reach hazardous surf heights
over the weekend.


Marianas Waters...None.


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