Area Forecast Discussion
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FXPQ60 PGUM 232026

Area Forecast Discussion
National Weather Service Tiyan GU
625 AM ChST Mon Apr 24 2017

.Marianas Synopsis...
Mostly cloudy skies with moderate winds prevail across the
Marianas. Scattered showers are seen across Guam, with isolated
showers across the CNMI. A tropical disturbance is evident to the
southwest of Guam.


No major changes to the inherited forecast. A developing tropical
disturbance continues to be the main focus for this week. Models
remain in fairly good agreement that scattered showers will be
across the Marianas through tonight. Beginning Tuesday morning is
where they diverge. The GFS is maintaining a fairly wet pattern
through the week, with scattered to numerous showers indicated
through at least Thursday. The ECMWF, however, shows a much drier
pattern after tonight, with most of the showers remaining to the
south and west of the Marianas. Chose to maintain the forecast as
is for now. Only isolated showers are present over the CNMI at
this time, with scattered showers over Guam. These showers are
expected to continue to develop northward through the day,
bringing scattered showers to the CNMI a little later this
morning. There have also been a few lightning strikes detected
over the southern Guam waters. Based on the model guidance being
very different after tonight, chose to maintain the forecast for
only isolated showers for the remainder of the week, with isolated
thunderstorms as well, due the unstable conditions indicated
across the region.


.Eastern Micronesia...
The main weather maker in Eastern Micronesia is a trade-wind
disturbance currently exiting Majuro and moving past Kwajalein.
The disturbance is expected to weaken as it moves westward with
the bulk of the showers passing north of Kosrae and only a
diminished wisp of a disturbance making it to Pohnpei. For the
most part the weather this week will be mostly cloudy with
isolated showers, with occasionally enough instability for a few

With all winds remaining below 20 knots, and winds staying below
15 knots at Pohnpei and Kosrae, and sea trends being flat to just
slightly down, no hazards are foreseen this week in Eastern
Micronesia. Around the weekend to early next week, there is a
possible north-northeast swell arriving at Majuro that could bear
monitoring for a possible high surf advisory.


.Western Micronesia...
The remaining convergence from air flowing into the tropical
disturbance near Yap should push through Chuuk today. After this,
the scattered showers should become isolated with winds decreasing
a bit. Koror is in the subsident area beyond the weather
associated with the circulation. They should have fairly dry
weather most of this week as a result. Yap will be borderline the
next day or two. Scattered showers are close we really
could not take them out, seeing as they did have some showers
earlier Sunday evening. So, we are currently looking for a high
PoP low QPF type event through tonight, then the PoP will lower.

With winds trending down at Chuuk and flat at Yap and Koror, and
with seas trending down, no hazards are foreseen this week in
Western Micronesia either. The tropical disturbance will certainly
be well away from Yap before it develops, and that is if it
develops, which is not at all certain.


Marianas Waters...None.


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