092
FXPQ50 PGUM 110747
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
547 PM ChST Thu Dec 11 2025

.Marianas Synopsis...
Satellite imagery shows partly cloudy skies. Radar imagery shows no
showers over the region. Altimetry shows combined seas of 6 to 8
feet, while buoy data shows 6 to 7 feet.

&&

.Discussion...
The main weather maker for this discussion is the shear line that is
just north of Saipan`s coastal waters. This feature is expected to
be somewhat quasi-stationary with a slow southward motion. Over the
next 24 to 36 hours, breaks in the cloud formations are anticipated
as the shear line begins to weaken and fragment. Current model
estimations suggest the shear line will fizzle out before it gets
over Saipan. Winds will remain the main concern even after the shear
line fizzles out. Winds are expected to be around 15 to 20 mph for
Guam and Rota. Winds over Tinian are expected to be slightly lower
than Saipan but remain in the range of 15 to 25 mph.

&&

.Marine...
The coastal regions is where the shear line from above is expected
to have the most effect on. Over Saipan`s northern waters, scattered
showers may occur, there is also a very small potential for "one hit
wonder" thunderstorms. Regardless, these showers are expected to be
short lived over the next 24 hours or so. Wind and seas are expected
to rise over the weekend before gradually tapering down by the middle
of next week. Models indicate that the peak sea height is
anticipated to arrive on Sunday. Sea heights are expected to be the
highest in Saipan`s waters and the lowest in Guam`s. Seas could reach
up to 11 feet. This will also coincide with a larger northeasterly
pulse from a distant mid-latitude system. High Surf Advisory (HSA),
High Risk of Rip Currents (HRRC) and Small Craft Advisory (SCA) are
very possible once this shear line gets a bit closer, however, at
this time it is too soon to tell the onset of these advisories and
statement`s conditions.

&&

.Eastern Micronesia...
Partly cloudy skies with spotty showers are seen over Pohnpei with
mostly cloudy skies and scattered showers at Kosrae and Majuro.
Altimetry shows seas between 4 and 6 feet across the region with
Kosrae and Pohnpei buoys agreeing with this, showing seas between 4
and 6 feet as well.

The main feature seen across eastern Micronesia this afternoon is an
Inter-Tropical Convergence Zone (ITCZ) that pushed into the region
overnight. This feature is interacting with an upper-level low, to
produce numerous to widespread showers and a few thunderstorms east
of Majuro. Bands of scattered showers are expected to move out of
this area and across Majuro through the night. By Friday morning, the
ITCZ is expected to be just south of Majuro, maintaining scattered
showers through the day. By Friday afternoon, the ITCZ looks to break
apart, with drier conditions moving into Majuro.

For Kosrae, the ITCZ is seen near the island, producing scattered
showers across the island tonight. By Friday morning, expect a brief
drier period. By Friday evening, the ITCZ looks to strengthen a bit
over the island, bringing scattered showers back through the weekend.
By Monday, a dry trade-wind pattern is expected to return to the
area.

For Pohnpei, a dry pattern looks to continue into the weekend. By
Saturday evening, a fragment of the ITCZ looks to move into the
state, bringing increased convection to Pohnpei through Sunday
afternoon. A dry trade-wind pattern is then expected to return for
the beginning of next week.

For the marine forecast, the main change is for an increasing north
swell moving into the region early next week. This swell was bumped
up about a foot for a brief period Monday and possibly into Tuesday.
Seas are expected to reach as high as 8 feet at Pohnpei and Majuro,
and up to 7 feet for Kosrae. Primarily gentle to moderate winds are
expected into next week, with Majuro seeing a brief period of lower
winds while Pohnpei could see occasional fresh winds next week.

&&

.Western Micronesia...
A near-equatorial trough (NET) remains stretched out across the
southern half of the region. Fairly quiet weather persists north of
this boundary, across the main islands of Palau, Yap, and Chuuk. Over
the next few days, an uptick in clouds and showers are expected at
times as trade-wind troughs move through Yap and Palau. Then,
trade-wind convergence looks to increase north of the NET axis,
initially increasing showers at Palau and Chuuk early next week.

Altimetry data continues to show combined seas of 4 to 6 feet near
Palau and 5 to 7 feet for Yap and Chuuk, which is comprised of
primary northeast trade swell and a background north to northeast
swell. The north to northeast swell is expected to further weaken
over the next day or so as it becomes indistinct from the trade
swell. However, seas look to increase a foot or so this weekend in
response to an increase in northeast to east trade swell and wind
waves. Pulses of long-period north swell emanating from distant mid-
latitude systems are expected to arrive at Chuuk starting early next
week, then to Yap and Palau around Tuesday. Model guidance indicates
patchy areas of moderate to strong winds south of the shear line, as
it begins to fragment north of 15N. Gentle to moderate winds look to
persist at Palau over the next several days, but moderate to fresh
winds with strong gusts at times are expected at Yap and Chuuk over
the weekend and early next week.

&&

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

$$

Marianas: Bowsher
East Micronesia: Kleeschulte
West Micronesia: Cruz