Area Forecast Discussion
Issued by NWS
FXPQ60 PGUM 050643
Area Forecast Discussion
National Weather Service Tiyan GU
445 PM ChST Mon Dec 5 2016
The High Surf and Small Craft Advisories were allowed to expire.
ASCAT Analysis shows fresh to possibly strong trade winds still
upstream of the Marianas, but local Aviation Obs show that wind
gusts have decreased below 25 kt this past couple of hours, and
VAD gradient winds are east about 20 kt. Local Buoys have been
reporting combined seas of 8 to 9 feet recently with a gradual
The GFS Model does still indicate a little deeper moisture along
with some cloudiness and a few showers early Wednesday and again
early Thursday. Showers could possibly be scattered at times but
should be relatively shallow and not very heavy. Pleasant weather
is expected most of this week. No significant changes were made to
the forecasts or gridded data.
Fresh to locally strong trade winds and combined seas of 7 to 9 feet
will continue the next few days. Sea conditions could flirt with
Small Craft Advisory criteria this evening and Tuesday afternoon,
but winds and sea should subside to a moderate to fresh trade wind
conditions later this week.
Showers and thunderstorms persist this evening across Chuuk and
Pohnpei, near and northeast of Kosrae and south of Majuro. Models
show this band of convection will continue the next few days,
generally between 4N and 6N with light southeast winds to the south
and fresh to strong trades to the north. Drier weather will
gradually push in from the east as trade winds slacken around
midweek from the Marshalls...westward to Chuuk and Pohnpei on
Thursday and Friday.
Fresh to strong trade winds persist this evening across the region
from Chuuk to Majuro. 00Z ASCAT pass shows 20 to 25 KT winds over or
very near Chuuk, Pohnpei and Majuro, so opted to extend the Small
Craft Advisory for these locations through the overnight hours.
Altimetry also supported hazardous seas at Majuro, Pohnpei and
Chuuk. Surf advisories also remain in effect for these 4 islands.
Surf should subside overnight across the region allowing surf to
fall below advisory levels on Tuesday at all or most locations.
Reasoning for the Chuuk forecast can be found under the Eastern
Micronesia discussion above.
A broad disturbance is seen south of Koror and Yap along a near-
equatorial trough. A weak circulation is centered within the trough
near 4N141E. Showers and thunderstorms persist in a broad area over
Palau and south of Yap to the equator. GFS and ECMWF show the trough
axis slowly lifting north, keeping showery weather over Koror, and
bringing it to Yap for the next few days. GFS shows the disturbance
developing near Yap by the weekend. ECMWF does not agree at this
time, so will have to watch closely in case inclement weather
becomes a concern.