Area Forecast Discussion
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Area Forecast Discussion
National Weather Service Tiyan GU
346 PM ChST Sat Jul 23 2016

.Synopsis...
Gentle east winds are filtering back into the Marianas waters this
afternoon as a weak trough out to the east moves slowly west.
Brief island showers are firing up along Guam`s western shores and
over Rota, and radar shows isolated showers about 50 miles
southeast of Guam, moving slowly west. Seas are still near 2 feet
at the buoys, though 3-ft seas are likely occurring in the eastern
fringes of the marine zones.

&&

.Discussion...
Have maintained isolated showers and thunderstorms Sunday and
Sunday night, and even extended them back into late tonight, but
otherwise no changes to the forecast. GFS seems to be backing off
on rainfall amounts during this time period, but it still shows
plenty of moisture, and the ECMWF brings in some decent rainfall
during the day on Sunday. Later in the week is uncertain for now,
as ECMWF has showers Monday night, and GFS is now hinting at
scattered showers around Wednesday. So have maintained partly
cloudy with isolated showers while awaiting better model
agreement.

&&

.Eastern Micronesia...
A trade-wind disturbance and an upper-level low between Chuuk and
Pohnpei are producing showers and a few thunderstorms in an area
that is approching Chuuk this afternoon while moving west of
Pohnpei. Farther east, trade-wind convergence could trigger a few
showers and thunderstorms near Kosrae and Majuro the next few days.
Otherwise, another surface trough upstream east of the date line
could be the next weather maker for Majuro by Monday or Tuesday,
then Kosrae, Pohnpei and Chuuk near midweek. Majuro/Kalo Buoy
shows combined seas near 4 feet.

&&

.Western Micronesia...
Reasoning for the Chuuk forecast can be found in the Eastern
Micronesia discussion above. Satellite and Ascat anaylsis indicate
an elongated weak circulation southeast of Koror at about 3N140E,
with a surface trough extending northeastward to south of Guam
near 12N145E. GFS Model indicates the circulation and trough will
drift slowly westward so the chance of showers and thunderstorms
will increase for both Yap and Koror the next few days. The bulk
of wet weather will pass across the area from Sunday night thru
Monday evening. Afterward, things will remain relatively wet thru
midweek as an upper-level low arrives from the east.

&&

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

&&

$$

Middlebrooke/Simpson



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