Area Forecast Discussion
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FXPQ60 PGUM 172159

Area Forecast Discussion
National Weather Service Tiyan GU
600 AM ChST Sun Mar 18 2018

.Marianas Synopsis...
A few showers were evident on radar this morning under a mostly
cloudy sky. Combined seas were mainly between 5 and 7 feet with
northeast wind.


Overall, the dry pattern continues through Wednesday. A weak
disturbance is moving through this morning and bringing some
isolated showers. The ECMWF is a little more robust with the rain
today, so will have to keep an eye on how things develop. Then it
is fairly dry until the tropical disturbance currently northwest
of Pohnpei moves between Guam and Yap around Thursday. Showers on
the north side of the system could begin to affect the area by
Thursday. There could be some scattered showers during the
Thursday to Friday time frame and we can hopefully resolve the
period better as we get closer. With the dry air in place, the
KBDI continues to creep up. However wind speeds look to fall just
short and humidity values will be right around threshold values,
so fire weather conditions will be monitored over the next few


Easterly swell will increase before decreasing slightly again
later in the week. If the tropical disturbance move a little
closer than forecast, than the seas will be higher than what is
currently expected. There is also a high risk of rip currents
through at least Tuesday.


.Tropical systems...
The circulation near Pohnpei has moved very little the past 12 to
18 hrs and convection has been on the down trend. Models still
develop showers and thunderstorms again later today and show an
eventual west to west-northwest motion in the next couple of days,
passing the system near Chuuk around Tuesday, and toward Yap
around Thursday. Models show some north to south variability in
the future track so there is still a fair amount of long-range


.Eastern Micronesia...
A circulation about 110 miles northwest of Pohnpei near 8N157E
will still dominate the weather pattern for the region the next
several days. Although models have maintained a slow west to WNW
movement, the circulation has remained stationary. Widespread
convection has diminished over night but some heavy showers are
still present in the northern waters of Pohnpei. The slow-moving
nature of the circulation will prolong unsettled weather at
Pohnpei and Kosrae the next couple of days with rain heavy at
times. Mudslides remain a possibility as additional rain continues
to fall on top of the nearly 2 feet in the past 4 days.

At Majuro, a trade-wind trough will bring scattered showers to the
area today. Over the next couple of days, as the circulation near
Pohnpei moves away, weaker southeast flow will develop over the
region which will help push showers and thunderstorms farther to
the north of Majuro.


.Western Micronesia...
The circulation near Pohnpei will eventually pass near Chuuk, but
with little westward motion yesterday and overnight, have slowed
down its progression. Current forecast follows a passage just
north of Chuuk around Tuesday with showers and thunderstorms
picking up Monday or Monday night. Yap and Palau will stay dry
with northeast trades the next few days, but both locations should
watch the circulation to the east for any development. It will
likely have some role in the local weather late in the week or
next weekend.


GU...High Rip Current Risk through Tuesday afternoon for GUZ001>004.

Marianas Waters...None.


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