Area Forecast Discussion
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Area Forecast Discussion
National Weather Service Tiyan GU
550 PM ChST Sun Feb 18 2018

.Marianas Synopsis...
Moderate to fresh trade winds and combined seas of 5 to 7 feet are
present in the Marianas waters. Visual satellite shows that any
significant showers are now west of Guam and passing southeast of
Guam, with only a few sprinkles at most over the rest of the region.

&&

.Discussion...
The next 24 hours look pretty dry, with moisture confined to below
5000 feet altitude, and only a slight chance of light showers. But
starting Monday night, moisture deepens to around 8000 feet and
sometimes more, supporting isolated mainly light showers the rest
of the week.

&&

.Marine...
Trades will be moderate to fresh for the coming week, with little
variation. Seas are expected to build starting on Tuesday as north
swell comes down from a strong winter storm east of Japan. East swell
will build only slightly, but it may be enough for a high rip risk
on east facing shores Wed or Thu.

&&

.Eastern Micronesia and Chuuk...
Dry northeasterly trade winds should continue to dominate Chuuk
Monday and Pohnpei thru tonight. A broad trade-wind disturbance is
gradually pushing westward over Kosrae this evening. The strongest
convergent winds are concentrating near the northern portion of this
disturbance, north of Kosrae between 7N and 11N. Therefore, the brunt
of the showers should stay north of the island. Nevertheless, widely
scattered showers and a thunderstorm or two are still possible near
Kosrae thru Monday evening. Moderate easterly trades in the wake of
the disturbance will also allow a period of less shower coverage near
Majuro thru Monday. A large dome of high pressure is building
southeastward from southern Japan toward Minami Tori Shima. This high
will channel fresh to strong trades toward the region near midweek.
Increasing trade convergence could trigger a period of unsettled
weather across the entire region initially. After midweek, much drier
trades will take over the weather from Chuuk eastward to the Marshall
Islands.

Trade-wind swell and wind waves will begin to build by midweek across
the area. These will combine with a long-period northwest swell to
cause rising seas and surf. Need to keep an eye out for hazardous
surf and small craft advisory conditions.

&&

.Western Micronesia...
Latest sounding data from Yap continues to reveal very dry air above
700 mb. Pleasant conditions associated with this air mass will stay
with Yap thru Wednesday and arrive at Koror by late tonight. The
next chance of rainy weather will be after midweek as a trade-wind
disturbance currently near Kosrae in Eastern Micronesia makes its
way westward.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...None.
Marianas Waters...None.

&&

$$

Middlebrooke/Chan



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