Area Forecast Discussion
Issued by NWS
FXPQ60 PGUM 220803
Area Forecast Discussion
National Weather Service Tiyan GU
530 PM ChST Sun Jan 22 2017
Fresh to strong winds, mostly cloudy skies and isolated showers
prevail across the Marianas this afternoon. A weak, diffuse shear
line is evident on visible satellite just south of Guam.
The major change on the forecast this afternoon is the decrease in
shower coverage over the region. Scattered showers were seen this
morning over the southern Guam waters, but never approached any
closer to the islands before significantly decreasing in area and
intensity. Due to the shear line continuing to dissipate, decided
to decrease showers to isolated over all the Marianas for tonight
and Monday morning. Otherwise, the forecast and reasoning remain
unchanged. Models still depict an overall unsettled pattern across
the Marianas through the end of the week. Breezy conditions are
also expected to return to the islands Monday, and are likely to
continue through the end of the week as well.
ASCAT analysis shows a broad area of 20 to 25 knot winds across
the Marianas waters. Models show these winds decreasing over
night, however, frequent gusts to 25 knots are expected to
continue through Monday morning. Therefore, the Small Craft
Advisory for Winds was extended until Monday morning. Latest buoy
readings show seas are primarily between 7 and 9 feet this
afternoon, with a few peaks around 9.5 at Ritidian. Seas will
continue to slowly build over the next couple of days, peaking at
around 12 feet Wednesday or Wednesday night. Seas could reach
Small Craft Advisory levels as early as Monday morning.
Moderate to fresh trade winds are observed across the region from
Chuuk to Majuro. Dry weather is present at Chuuk and Pohnpei this
evening, but trade wind showers and thunderstorms extend eastward
from southeast of Pohnpei, across Kosrae and Majuro to beyond the
date line. This band of showers will shift west to Pohnpei and Chuuk
as drier weather builds in at Majuro and Kosrae around midweek.
Another trade-wind convergence band will bring more showers and
thunderstorms to the region from east to west by the end of the
Trade wind swell and wind waves will maintain hazardous seas for
small craft at least through midweek from Chuuk to Majuro. Winds
will become hazardous to small craft on Monday at Majuro. In
addition to the hazardous winds and seas, hazardous surf at Kosrae`s
eastern shores will spread to north-facing shores tonight. Surf will
build to hazardous levels along Majuro`s east facing shores tonight.
Discussion for the Chuuk forecast is included in the Eastern
Micronesia section above.
The remnants of a shear line will keep clouds near Yap and Koror
this evening but most showers will keep just to the north of both
locations. Fair and breezy conditions are expected the next couple
days over the region as a strong ridge builds eastward across the
north Pacific. Later in the week, a disturbance will pass south of
Yap and Koror and could bring rainy/windy conditions to both
Winds and seas will be hazardous for small craft by Monday in
response to the breezy conditions across the region. Surf will
likely become hazardous along north and east facing reefs by Monday
afternoon or evening as northeast trade wind swell build at Yap and
Marianas Waters...Small Craft Advisory for winds until 6 AM CHST
Monday for PMZ151>154.