Area Forecast Discussion
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FXPQ60 PGUM 190752
AFDPQ

Area Forecast Discussion
National Weather Service Tiyan GU
542 PM ChST Tue Sep 19 2017

.Marianas Synopsis...
Andersen Air Force Base Doppler weather radar shows only isolated
showers within the Marianas waters. The buoys show a northwest
swell of around 3 feet and trade-wind waves around 3 feet. The VAD
wind profile reveals east-northeast winds of 10 to 15 knots
through the lowest 7 thousand feet of the air.

&&

.Discussion...
Trade winds are gradually building back into the Marianas. Upper-
level lows have moved away allowing the thunderstorms to subside
briefly. Another upper-level low is moving toward us and will
bring them back soon. Looks like the next chance for significant
rainfall is around Saturday night and could last through Monday
night.

&&

.Marine...
Northwest swell is expected to abate starting Thursday, leaving us
primarily with east swell. This will also allow the risk of rip
currents to become low rather than moderate.

&&

.Eastern Micronesia...
Showers and thunderstorms are seen from Kosrae to the southern
Marshalls near a surface trough and preceding zone of trade-wind
convergence. This trough will slowly head west bringing a slight
increase in showers to Pohnpei Wednesday night and even more on
Friday. Models show the ITCZ becoming a little more active the latter
half of the week. This is expected to bring more showers to Majuro
and Kosrae as early as Wednesday night. The bulk of showers is
expected to stay south of 10N, although ECMWF shows more northward
spreading, up to around 14N on Thursday.

&&

.Western Micronesia...
A broad disturbance is seen near and southeast of Yap and Koror. A
weak circulation is centered near 10N147E, but nearly all
convection is found well to the southwest. Another cluster of
showers and thunderstorms is seen to the east along a surface
trough that is being enhanced by an upper-level low near 11N149E.

Models maintain the disturbance the next several days as it edges
westward. Wet weather will persist at Yap and Koror through Wednesday
or Wednesday night before showers taper off as a surface ridge
reaches the area. However, another trough will bring showers and
thunderstorms back around Sunday. Gentle south winds and dry weather
at Chuuk will continue for a couple days before a trough reaches the
area from the east. Showers will increase on Friday and eventually
diminish over the weekend.

&&

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

$$

Stanko/W. Aydlett



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