916
FXPQ50 PGUM 080816
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
616 PM ChST Sun Feb 8 2026

.Marianas Synopsis...
Showers and cloud cover have been decreasing across the Marianas
today as drier air filters into the region. A drier pattern is
expected through most of the week though features such as a cold
front to the north and later a developing trade-wind surge around
mid-week could influence this trend. Seas are around 4 to 6 feet but
are expected to build rapidly around Tuesday as a northerly swell
moves into the region, potentially pushing seas to around 10 feet and
surf to hazardous levels of at least 9 feet along west and north
facing reefs. Light to moderate east to southeast winds will also
build by mid-week in response to a trade-wind surge.

&&

.Discussion...
Showers around the Marianas have been steadily decreasing since late
this morning as the Blended-Total Precipitable Water (TPW) satellite
product shows TPW values of 1.9-2.0 inches this morning being
replaced by drier air from the east with values around 1.20-1.35
inches. Global model guidance supports a fairly dry pattern for
through the end of the week as this drier air lingers across the
region. However, the evolution of the cold front currently well north
of the Marianas, and then the trade-wind surge expected to develop
around mid-week will need to be monitored. Models show the cold front
transitioning into a shear line and moving towards the Marianas
around Tuesday or Wednesday, around the same time the trade-wind
surge is expected to develop. If the dry air remains entrenched
across the Marianas, these features will likely lead to breezy
conditions but the risk for heavier showers will be limited, but if
there is an increase in moisture, then the potential for showers
could increase. Breezy conditions are expected to end around Thursday
as both the shear line and trade surge weaken.

&&

.Marine...
Combined seas of 4 to 6 feet will decrease to 3 to 5 feet Monday.
Large northerly swell, generated behind a cold front that is
moving off the coast of Japan, is expected to approach the
Marianas around Tuesday or Tuesday night. This will lead to a
rapid increase in seas, building to hazardous levels around 10
feet Tuesday night and Wednesday. This will also quickly build surf,
especially along west and north facing reefs, with hazardous surf of
9 feet or greater also looking likely during the by the Tuesday night
time frame. Light to moderate east to southeast winds are expected
through Monday night, increasing to moderate to fresh Tuesday and
Wednesday as the shear line drops southward towards the Marianas,
while a trade surge builds as high pressure develops over Japan,
helping to increase the choppiness of seas around mid-week.

&&

.Eastern Micronesia...

The main items of interest are the High Surf Advisory for north and
east facing reefs at Kosrae, and rainfall probabilities at Pohnpei
and Kosrae over the next 48 hours. Currently, a surface trough
stretches north from a broad circulation well south of Pohnpei near
3N159E. This trough is moving slowly west and will bring numerous to
widespread showers and isolated thunderstorms to Pohnpei tonight and
Monday, and to Kosrae tonight. Some of this rainfall may be locally
heavy. Then, as the trough continues west away from the region,
rainfall will gradually diminish.

As for the High Surf Advisory at Kosrae, upstream altimetry near
170E shows total sea heights of 7 to 8 feet, suggesting swells
capable of producing hazardous surf of at least 9 feet along north
and east facing reefs. Thus there was good reasoning to hoist the
advisory and this remains in place through 3 PM Monday. Then, surf
will subside at Kosrae for a few days, before surf builds area-wide
towards the end of the week.

As for marine conditions, moderate to fresh winds will prevail
through much of the forecast period as a trade-wind surge builds
across the region, decreasing slightly from east to west for the
latter half of the week. Recent scatterometer data showed a pocket
of 15 to 20 knot winds stretching from east of Pohnpei to near 170E.
Seas of 6 to 8 feet may build a foot or so towards the week`s end.

&&

.Western Micronesia...
Visible satellite this afternoon reveals a generally unsettled
pattern across the region. Scattered to numerous showers are seen
over and just north of Palau and Yap, associated with a weak,
elongated circulation focused roughly about 7N139E, southeast of the
major islands. A broad surface trough extends south-southeast into
the circulation, passing just west of Yap Proper, and most of the
showers are focused along this trough axis. Far to the east, visible
satellite reveals lines of isolated showers approaching Chuuk waters
from the east-northeast, but upper-level clouds are increasingly
blanketing the area from strong convection far to the southeast.
Scattered showers continue for Palau and Yap through the next day or
so as the weak disturbance stalls nearby to the south, gradually
shifting south and westward as it is absorbed into the near-
equatorial trough. The next disturbance, a robust trade-wind trough
approaching from eastern Yap State, arrives around midweek bringing
numerous showers and isolated thunderstorms to the area. Then, a
drier trade-wind pattern takes over near the end of the week. The
aforementioned disturbance, currently a broad trough stretching
across much of Pohnpei State, will first bring unsettled weather
across Chuuk, with scattered to numerous showers and isolated
thunderstorms expected through Monday night as it lifts northwest
into the area.

Recent altimetry data indicates combined seas around 3 to 5 feet near
Palau and Yap, and 4 to 6 feet for Chuuk. Seas will build by several
feet for Palau and Yap starting Tuesday as a large north-northwest
swell moves into the region, potentially building surf to hazardous
levels of 9 feet along north and west facing reefs. Chuuk will see
the arrival of large swell later around Wednesday, which could
bring hazardous surf along north reefs there as well, but the main
concern for Chuuk waters will be a building trade-wind surge across
the region. Trades look to become fresh to strong Tuesday and Tuesday
night, potentially sustaining above 22 knots at times and generating
rough seas hazardous to small craft. Winds will gradually relax in
the latter half of the week, becoming gentle to moderate come Friday.

&&

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

$$

Marianas: Schank
East Micronesia: Doll
West Micronesia: DeCou