835
FXPQ50 PGUM 260721
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
521 PM ChST Sat Jul 26 2025

.Marianas Synopsis...
Radar and satellite imagery are showing cloudy skies with scattered
to numerous showers across the Marianas. Tropical Storm Krosa has
been nearly stationary the past few hours to the west of Agrihan,
Pagan and Alamagan. Local buoys and recent altimetry passes are
indicating seas of 12 to 16 feet in the coastal waters.

&&

.Discussion...
TS Krosa has been slow to trek to the north today away from the
Marianas. As a result, the monsoon surge tailing Krosa will continue
to bring strong winds and occasional heavy showers for Rota, and
especially Tinian and Saipan. The Flood Watch remains in effect for
the CNMI through tonight and extended the Wind Advisory through
tonight as well for the CNMI. Winds and shower coverage will be less
for Guam as the bulk of the monsoon surge remains north across the
CNMI. Krosa still expected to pick up its pace to the north away
from the region by early next week and ridging and much calmer
conditions building into the Marianas.

&&

.Marine/Surf...
Recent altimetry passes and local buoys are showing seas 12 to 16
feet in the coastal waters, which is in the Hazardous Seas criteria
of 15+ feet. Have reissued the Hazardous Seas Warning for Rota,
Tinian and Saipan through tonight, with a Small Craft Advisory then
in effect through Sunday night. The Small Craft Advisory was also
extended for Guam through Sunday night as well.

The large westerly swell and southwest wind waves are causing large
surf at Guam and dangerous surf for the CNMI, as well as coastal
flooding. A High Surf Warning is in effect for the CNMI along south
and west facing reefs, with a High Surf Advisory along north facing
reefs. A Coastal Flood Warning is also in effect along south and west
facing reefs of the CNMI. A Coastal Flood Advisory is in effect
along south and west facing reefs of Guam, with a High Surf Advisory
along south, west and north facing reefs.

Winds, seas, and surf will slowly diminish early next week as TS
Krosa and the monsoon surge slowly drift away to the north.

&&

.Tropical Systems...
Tropical Storm Krosa (12W) is centered west of Pagan near 18N144E,
remaining nearly stationary, crawling in an easterly at 3 mph.
Maximum sustained winds are 60 mph. Krosa is expected to turn toward
the north-northeast through the night with an increase in speed. The
slow movement of Krosa is expected to maintain tropical storm force
winds over the northern CNMI at least through tonight. Krosa is not
expected to become a typhoon over the next few days, until it is well
north-northwest of Pagan.

For more information on TS Krosa (12W), please refer to bulletins
issued by JTWC under WMO header WTPN31 PGTW and from the National
Weather Service under WMO header WTPQ31 PGUM. For island specific
details for the northern islands of Agrihan, Pagan and Alamagan,
please see the TS Krosa local statement under WMO header WTPQ81 PGUM.

&&

.Eastern Micronesia...
A dry, quiet pattern remains across eastern Micronesia this
afternoon. Latest model guidance indicates that an Inter-Tropical
Convergence Zone (ITCZ) will develop near the Date Line Sunday night
and push into the region through the coming week. However, guidance
seems to be a bit heavy handed with rainfall potential and shower
coverage. The majority of the convection will remain south of Pohnpei
until around Monday night. For Kosrae and Majuro, increased
convection is expected Sunday night through most of the week.

Marine conditions look to remain unimpressive. Combined seas are
expected to be between 3 and 4 feet for Pohnpei and Kosrae and
between 3 and 5 feet for Majuro. Pohnpei and Kosrae will see light to
gentle winds through the end of next week. Gentle to moderate winds
at Majuro tonight will become light to gentle early next week.

&&

.Western Micronesia...
A dry ridging pattern continues across western Micronesia, well south
of the monsoon trough and Tropical Storm Krosa. Himawari visible
satellite shows partly cloudy skies and isolated showers over Palau
and Chuuk, with swaths of upper-level cloud debris drifting south
over Yap from convection wrapping into TS Krosa. Scattered showers
are developing just north of Yap Proper this afternoon, along the
outer edge of the monsoon convergence. To the southwest, shower
coverage looks to increase slightly near Palau late tonight, with
slight variations in the wind pattern just north of the area
generating some localized convergence. Other than the occasional,
similarly brief weak feature, Yap and Palau can expect a quiet drier
pattern with isolated showers through the week.

Chuuk will start to see more showers early next week as the
southeasterly trades enhance convergence and convection further
north across the region, along the western extent of an ITCZ
fragment. The general pattern looks to keep most of the showers south
of Chuuk Lagoon, with the best shower chances sometime between
Tuesday night and Thursday.

Benign marine conditions are expected through the forecast period.
Buoy and altimetry data show combined seas of 2 to 4 feet near Palau
and Yap, and between 3 and 5 feet near and just north of Chuuk. For
Palau and Yap, seas are comprised of a primary east to southeast
trade swell and a secondary pulse of northeast swell associated with
TS Krosa. Northeast swell will diminish by Monday as a west to
southwest monsoon swell reemerges to stick around through the rest of
the forecast period, where seas will remain comprised of a mix of
monsoon and trade swell. A 3 to 4 foot trade swell will prevail
across Chuuk through early next week, but a west to northwest swell
may enter the region around Wednesday, steered by the monsoon pattern
and tropical systems far north to northwest of the region. Winds will
overall remain mostly light to gentle across western Micronesia.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...Coastal Flood Advisory until 6 AM ChST Sunday for GUZ001.

     High Rip Current Risk through late tonight for GUZ001.

     High Surf Advisory until 6 AM ChST Sunday for GUZ001.

MP...Flood Watch through late tonight for MPZ001>003.

     Coastal Flood Warning until 6 AM ChST Sunday for MPZ001>003.

     High Rip Current Risk through Sunday afternoon for MPZ001>003.

     High Surf Warning until 6 AM ChST Sunday for MPZ001>003.

     Wind Advisory until 6 AM ChST Sunday for MPZ001>003.

     High Surf Advisory from 6 AM to 6 PM ChST Sunday for MPZ001>003.

Marianas Waters...Small Craft Advisory until 6 AM ChST Sunday for PMZ151.

     Hazardous Seas Warning until 6 AM ChST Sunday for PMZ152>154.

     Small Craft Advisory from 6 AM to 6 PM ChST Sunday for PMZ152>154.

&&

$$

Marianas: Slagle
East Micronesia/Tropical: Kleeschulte
West Micronesia: DeCou