Drought in Guam, November 1 to 30, 2020

Area Forecast Discussion
National Weather Service Tiyan GU
602 PM ChST Sat Oct 31 2020

.Marianas Synopsis...
Moderate southeast winds and isolated showers are seen across the
Marianas. A ragged TD Atsani remains to the west near 14N139E. Buoys
show seas between 4 and 6 feet.

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.Discussion...
A dry pattern will dominate the region as moderate southeast winds
shift to the east Sunday. Little change is expected through Tuesday,
but winds will begin to increase Wednesday as a disturbance, now SW
of Kosrae, approaches the region. Clouds and showers will increase
Thursday with scattered showers expected by Friday. While models
continue to hold steady in generally showing a surface trough moving
by, a couple runs of the GFS point toward a small circulation. The
shared effect seen in all the models is a pronounced increase in
easterly winds between Wed and Thu. Have made a blend of GFS and
ECMWF winds to bridge the two, maxing winds around 25 mph around
Thursday night. While moisture is expected to decrease Saturday
night, the latest GFS hints at a convergent southeast flow that could
prolong moisture and cloudiness into Sunday.

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.Marine...
Seas will fall about a foot by Monday, but will slowly rise Wednesday
in response to increasing trade winds. Seas and winds will approach
hazardous levels for small craft around Thursday as the disturbance
approaches the region.

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.Tropical systems...
A weak TD Atsani continues to slowly move away, devoid of deep
central convection. While it will have no effect on the Marianas,
southwesterly flow south of Atsani and STY Goni will generate a small
westerly swell that will move into the Marianas the next several
days.

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.Eastern Micronesia...
JTWC invest area 91W continues to slowly move west, with a broad
circulation located south of Kosrae. This disturbance stretches
broadly from the circulation, then extends northeast towards
Kwajalein and Majuro.

The GFS and Euro are once again in good agreement; the good news is
both models do not expect significant organization from this invest
area. Even without an organized storm the system will cause
scattered showers and isolated thunderstorms tonight and Sunday for
Majuro and Kosrae. Additionally, the latest wave guidance has a
short time frame of 9 foot combined seas to Kosrae on Sunday evening
and through the night. The next shift will have to watch this trend
closely to see if a high surf advisory will be necessary.
By Sunday night or Monday the disturbance will reach Pohnpei causing
scattered showers and isolated thunderstorms weather in the region.

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.Western Micronesia...
The effects of Tropical Depression Atsani and Super Typhoon Goni are
still being felt across the region. Winds near Koror stayed
consistently near 12 knots from the southwest and had gusts up to 20
knots at times today. This was not enough to warrant a Small Craft
Advisory but should be monitored closely as ASCAT imagery did show
winds around 30 knots to the southwest this morning. Farther west
Chuuk is under a weak ridge with calm seas and skies.

The forecast for Yap was adjusted to indicate locally heavy showers
until midnight as current satellite and models keep convection
firmly rooted in place over night. GFS and Euro also keep convection
in the region until the start of the week when things will begin to
dry out. This drying out will be modest as models keep moisture in
the region along with several rounds of showers from unorganized
disturbances through the rest of the week.

Chuuk will stay dry for the rest of the weekend and into the start
of next week as the ridge will stay in place through Tuesday.
Tuesday night, however, the GFS and Euro are in good agreement for
an disorganized disturbance to move into Chuuk State. This will
bring showers and thunderstorms for the rest of the week as well.

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

W. Aydlett/Slaughter