Drought in Guam, September 1 to 30, 2020

Area Forecast Discussion
National Weather Service Tiyan GU
543 PM ChST Mon Aug 31 2020

.Marianas Synopsis...
Mostly cloudy skies and moderate winds prevail across the Marianas
this afternoon. Scattered showers and isolated thunderstorms are seen
across Tinian and Saipan, with scattered showers seen to the east of
Rota and Guam waters. Buoys show seas between 3 and 5 feet with
altimetry data showing higher seas to the west.

&&

.Discussion...
A surface trough extends southward from a weak disturbance centered
near 24N145E. This trough, along with upper-level divergence, is
generating scattered showers and isolated thunderstorms across Tinian
and Saipan this afternoon. Off to the east, another disturbance
approaching the islands is responsible for scattered showers to the
east of Guam and Rota. This approaching disturbance will help to
spread scattered showers southward into Rota early this evening and
into Guam around midnight. The islands will remain under the
influence of this system through Tuesday afternoon, with showers
gradually clearing through the day from the north. By Tuesday night,
scattered showers will be over Guam with isolated showers over the
CNMI. Isolated thunderstorms will remain in the forecast for all the
islands through Tuesday night. Drier conditions will move into the
region by Wednesday morning and continue through the end of the week.

Models are indicating that another round of showers and thunderstorms
are possible Friday into the weekend. Maintained the current forecast
for isolated showers and thunderstorms for now as low-level moisture
looks to be a bit low. Although this could change over the next few
days.

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.Marine...
Combined seas of 5 to 7 feet tonight are comprised of mostly a west
swell from Typhoon Maysak. As maysak continues to move farther north
and away from the islands, the west swell is expected to gradually
shift northwestward and subside. Seas are expected to fall to between
3 and 5 feet by Tuesday night. Moderate winds will also subside to
gentle by Wednesday.

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.Tropical systems...
Typhoon Maysak continues to move north, away from Micronesia, and is
centered near 23N128E. The only affects from Maysak continue to be
increased west to north swell over western Micronesia and the
Marianas. Another disturbance, an invest area,  remains to the north
of the northern CNMI near 25N146E. Models are in good agreement with
this circulation slowly developing over the next couple of days and
has been upgraded to medium probability of developing into a
significant tropical cyclone within the next 24 hours. This system
will have no direct impact on the Marianas as it develops.

&&

.Eastern Micronesia...
Weather is currently fairly quiet in eastern Micronesia this
evening, with partly cloudy skies and gentle trade winds. But
satellite shows a trade-wind disturbance about to cross the date
line with clouds and scattered showers. This should be the main
weather-maker the next few days as it moves west, bringing scattered
showers and isolated thunderstorms to Majuro Tuesday night through
Wednesday night, to Kosrae on Thursday, and to Pohnpei Wednesday
night into Friday. Combined seas are expected to be in the 3-5 ft
range across the region, but will reach 6 ft at times at Majuro
Tuesday night through Wednesday night.

&&

.Western Micronesia...
This evening's weather in the west is dominated by a large tropical
disturbance with an ill-defined center near 7N140E. This will bring
clouds, scattered showers and isolated thunderstorms to Palau for
tonight, but by Tuesday morning the GFS weakens it and pushes it out
to the west. At Yap, the showers and thunderstorms of earlier today
have ended, and the rest of the week looks relatively quiet with
isolated showers, along with isolated thunderstorms at times. The
trade-wind disturbance in eastern Micronesia could bring scattered
showers and thunderstorms to Yap late Saturday, but have left that
isolated for now. For Chuuk, the next couple of days should be fair,
with isolated thunderstorms tonight and again Wednesday night, but
just isolated showers Tue-Wed. But then that disturbance in the east
should arrive Thursday with scattered showers and isolated
thunderstorms that are expected to extend through most of Friday.
Combined seas should be in the range of 3 to 5 feet at all locations.

&&

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

Kleeschulte/Middlebrooke