Area Forecast Discussion
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FXPQ60 PGUM 272119

Area Forecast Discussion
National Weather Service Tiyan GU
714 AM ChST Fri Jul 28 2017

.Marianas Synopsis...Southwest winds and isolated showers prevail
over the Marianas this morning.


.Discussion...A few changes made to the forecast. Did update winds
with new model data and decreased northeast swell.

Observations from the Marianas showed winds to be light and variable.
Radar VAD wind profile indicated winds at 2000 ft from the southwest.
The winds at that level increased through the morning from around
5 mph to 8 mph. Models do show winds a little higher than they have
been so expect southwest winds of 10 to 15 mph today.

Sounding data from last night showed that moisture has decreased a
little from 24 hours ago. With the slight increase in winds and a
decrease in moisture, do not expect the afternoon scattered showers
that occurred the last two days.

Southwest winds of 10 to 15 mph will continue through at least the
weekend. Models hint at an higher wind speeds by mid-week as monsoon
flow increases. Deep layer moisture will not really change much so
only expect isolated showers, even during the afternoon hours this


Observations this morning from Ritidian, Tanapag, and Ipan buoys
indicate combined sea heights around 2 to 4 feet. Models show a few
five foot seas are possible. Expect sea heights of 3 to 5 feet
through the weekend.

The buoys still show a northeast swell and a southwest swell. This
swell has decreased and Wave watch model projections agree. Lowered
the northeast swell to 2 feet through the weekend.

The southwest swell remains high enough to produce surf of 3 to 5
feet on west facing reefs. The surf on the east facing reefs has
decreased to 1 to 3 feet.

Distant Typhoon Noru will continue to churn north of the area through
the forecast. As Noru stirs up the ocean and creates swells, some of
those will head towards the local area. The swells from the typhoon
may start to enter the Marianas by the beginning of next week. This
swell will increase surf on north facing exposures. The southwest
swell will gradually turn to the west.

The swell from the typhoon may become large enough to generate
hazardous surf on north facing reefs by Monday night.


.Eastern Micronesia...
Quiet weather is seen over Pohnpei and Majuro this morning. However,
trade-wind convergence and an upper-level low north of Kwajalein are
generating scattered showers and a few thunderstorms across Kosrae
State and south of Majuro. Showers and a few thunderstorms are also
just east of Majuro. The upper low will track WSW the next day or two
with most convection keeping to the south of the circulation. Expect
isolated thunderstorms through Saturday at Kosrae and Pohnpei. Drier
weather will build in at Majuro tonight and westward to Kosrae and
Pohnpei Saturday night. Models show a weak trough or circulation
materializing near Kosrae early next week that could generate showers
and isolated thunderstorms then, with gentle and variable winds near
Kosrae and Pohnpei.


.Western Micronesia...
A weak ridge remains in place southeast of Yap and Koror with gentle
southwest to west winds over the islands. IR satellite shows quiet
conditions in place with only spotty convection north of Yap and
Koror. Models still show a benign monsoonal weather pattern the next
several days, therefore, there was little change made to the inherited
forecast of isolated showers and a slight chance of thunderstorms.

Scattered showers and isolated thunderstorms persisted overnight
southeast of Chuuk. Much of this weather will keep just southeast and
south today, but cannot rule out a few thunderstorms today within
the coastal waters. Gentle south winds over the state with a weak
ridge northeast will maintain current conditions at least into
Saturday. A weak disturbance will bring a better chance of showers
and thunderstorms late Saturday and Sunday. Relatively drier weather
will return Monday.


Marianas Waters...None.


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