300
FXPQ50 PGUM 042041
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
641 AM ChST Wed Nov 5 2025

.Marianas Update...
Satellite observations show partly cloudy skies and isolated showers
across the CNMI and mostly cloudy skies and scattered showers across
Guam. Altimetry and buoy data show combined seas between 6 and 9
feet.

Overall, only minor edits were made with this forecast package. The
onset of heavy rainfall was delayed and shifted southward a bit due
to a southwestward shift in the track of Tropical Depression 32W.
Both deterministic and probabilistic guidance continue to show the
threat for heavy rainfall and gusty winds across Guam and Rota
through Friday afternoon.

Little change was made to the Marine forecast. Strong to near gale
winds remain possible across Guam`s southern coastal waters with
fresh to strong winds expected northward across the coastal waters
of the CNMI. A Small Craft Advisory remains in effect for the coastal
waters of Guam and Rota through Friday afternoon. A High Surf
Advisory and a High Risk For Rip Currents is in effect for south
facing reefs of the Marianas. The High Surf Advisory may need to be
expanded to west facing reefs later this week as Tropical Depression
32W moves to the west of the Marianas. Additionally, a High Risk for
Rip Currents will be possible late this week across east facing reefs
as the trade-wind swell reinforces the swell from Tropical
Depression 32W.

&&

.Hydrology Update...
Only minor changes were made to the hydrology forecast. The track for
Tropical Depression 32W has shifted further south than in previous
forecast packages, shifting the core of the rainfall south with it.
That said, 32W`s moisture envelope remains large and heavy rain still
looks to impact Guam and Rota the next few days. 4 to 8 inches of
rain remain possible through Friday afternoon, but this forecast will
need to be adjusted downward if the path of Tropical Depression 32W
continues to adjust southward. Flash Flooding remains possible where
the heaviest rain falls.

&&

.Tropical Systems Update...
Tropical Depression 32W remains elongated across eastern Yap State,
with little consolidation seen overnight as it has drifted slowly
south to southwestward. The center is now located at around 8.4N
141.6E to the east of Sorol, well to the south-southwest of Guam, and
it is moving south at around 8 mph. Numerous to widespread heavy
showers and isolated to scattered thunderstorms continue to develop
within TD 32W, focused mainly southwest to south about the
circulation center early this morning. Maximum sustained winds remain
at 35 mph. 32W is forecast to make a turn to the north-northwest
through this afternoon and intensify as it does so, moving toward
Ulithi and Fais in Yap State, likely strengthening to a tropical
storm as it approaches. A Tropical Storm Warning has been issued for
Ulithi and Fais, meaning tropical storm conditions, including winds
of 39 to 73 mph, are expected within 24 hours. 32W is expected to
pass to the southwest of the Marianas through Thursday night as it
makes a west-northwest turn into the Philippine Sea, possibly
becoming a typhoon on Thursday.

For more information on Tropical Depression 32W please see bulletins
for the Western/Southern Pacific Ocean issued by the Joint Typhoon
Warning Center under WMO header WTPN32 PGTW.

&&

.Eastern Micronesia Update...
Little change was made with this forecast package. Quieter conditions
continue across eastern Micronesia with just a couple of troughs
producing scattered showers east of the Marshall Island and north of
Kosrae. The forecast is expected to generally remain quiet over the
next few days for the region. A Coastal Flood Statement continues
for Majuro through Saturday afternoon. Coastal flooding of 1 to 2
feet is expected due to a combination of high tides and a trade-wind
swell.

No changes were made to the marine forecast.

&&

.Western Micronesia Update...
Tropical Depression 32W remains the dominant feature across western
Micronesia, making up much of the eastern extent of the monsoon
trough that extends across the region. TD 32W has been drifting
slowly south early this morning, and remains elongated across eastern
Yap State with little consolidation seen overnight. Numerous heavy
showers and isolated to scattered thunderstorms are seen across much
of the region east of Palau and Yap, and west of Chuuk. Overall,
there was little change to the forecast. Showers were increased
slightly to low-end scattered (30 percent chance) for Chuuk as it
remains on the outer periphery of convergence and showers wrapping
into the slow-moving 32W. There was no change to the marine forecast.
A Small Craft Advisory is in effect for Yap from late this afternoon
through Saturday afternoon with elevated winds and seas expected as
32W strengthens, passing to the northeast over the next few days.

&&

.Prev discussion... /issued 653 PM ChST Tue Nov 4 2025/

Marianas Synopsis...
There are several watches and advisories that have been issued. There
is a Small Craft Advisory for Guam and Rota. There is also a flood
watch, high surf and high risk of rip currents issued for Wednesday
through Friday.

Satellite imagery shows mostly clear skies with little to no
showers. Altimetry shows combined seas of 7 to 8 feet, while buoy
data shows about 7 feet.

Discussion...
A wet and unsettling pattern is expected for the Marianas especially
for Guam and Rota. However, Tinian and Saipan can expect to see what
the lower two island experience, but to a lesser degree and a bit
later. As Invest 90W (which is expected to become a tropical
depression) and the convergence zones to the north of 90W are
expected to bring periods of heavy showers to the region and through
the rest of the work week. Both of these features are also producing
winds up to near-gale. These winds will cause loose items to be blown
away. This system is estimated to produce 5 to 8 inches of rain
through Friday. Over the weekend, trade-wind troughs are expected to
keep rain in the forecast.

Both the surf and risk of rip currents were heavy-handed for this
forecast cycle. Surf is anticipated to rise to to near 11 feet by
Wednesday night along east facing reefs and 10 feet along south
facing reefs. Depending on how 90W move this may need to be toned
down.

Marine...
Moderate to fresh trades with frequent near-gale force gusts will
continue to build through at least Friday as Invest 90W passes
to the southwest of Guam, around Wednesday night into Thursday
morning. Combined seas of 5 to 8 feet are expected to build to
near 12 feet over this time frame. Seas are expected to remain
high over the weekend. Small Craft advisory has been issued for
Guam and Rota due to the elevated winds. Tinian and Saipan should
prepare for these condition to move into their coastal waters in a
day or so.

Hydrology...
A Flood Watch will begin at 4 AM for Guam and Rota and continuing
through Friday afternoon. Confidence is highest for the potential of
flash flooding over Guam due to closer proximity of Invest 90W.
Uncertainty regarding mudslide risk during the weekend remains high.
Guidance continues to show prolonged surface convergence setting up
over the Marianas by late Friday, leading to continued heavy
rainfall. The continued rainfall into the weekend would likely
saturate soils enough to increase mudslide risk. Additionally, the
Flood Watch may need to be extended to Tinian and Saipan this weekend
depending on the exact location of the convergence zone. Residents
should continue to closely monitor the developing situation as flood
watches, advisories, and flash flood warnings could be issued later.

Tropical Systems...
A circulation, known as Invest 90W, is centered near 10N143E near
Gaferut in Yap State, and embedded within the monsoon trough that
extends across western Micronesia. Invest 90W continues to
consolidate and is expected to become a tropical depression later
this evening. Scatterometer data this morning showed winds of around
25 to 30 kts along the northeast to eastern flanks of the circulation
center, mainly associated with heavy showers and thunderstorms near
90W`s center. 90W is expected to slowly move in a westerly direction
and then move more northwest as 90W`s circulation becomes more
organized.

For more information on Invest 90W please see bulletins for the
Western/Southern Pacific Ocean issued by the Joint Typhoon Warning
Center under WMO header WTPN21 PGTW.

Eastern Micronesia...
The main forecast concern is a large swath of 20 to 25 knot winds
near Wake Island, and when will the resultant northernly swell
arrive. Also of note is a Coastal Flood Advisory as a building trade
trade swell interacts with the building northerly swell this week.
The northerly swell looks to begin to increase late Thursday night
or Friday at Majuro and Kosrae, reaching Pohnpei by Saturday. At this
time it doesn`t look like any headlines will be needed at Pohnpei or
Kosrae later this week, but stay tuned. Otherwise, the models
indicate increasing rainfall potential as an ITCZ attempts to build
across the area behind a lead surface trough, which is currently
crossing the Date Line.

Marine conditions for Pohnpei and Kosrae. Light to gentle winds at
Pohnpei and Kosrae will become gentle to moderate by Thursday night.
Seas near 5 feet will increase a foot on thursday into Thursday
night. Farther east at Majuro, seas of 6 to 8 feet, highest along
the windward side of the northern and eastern reefs/atolls will
gradually decrease this week. Then as we head into the weekend, seas
look to decrease a foot but this will be dependent on the magnitude
and timing of the northeast swell.

Western Micronesia...
Invest 90W remains the major weather feature in the region,
generating heavy convection that will continue to build over the
eastern islands of Yap State as Invest 90W consolidates, likely
becoming a tropical depression later this evening. Model guidance
indicates 90W will slowly move in an overall northwest direction over
the next few days, likely passing between Yap and the Marianas. This
will drag the monsoon trough north and west, pulling the heavy
showers further west across Yap State and towards Yap Proper and
surrounding islands. Strong to gale-force west to southwest
monsoonal winds and gusts and heavy showers and thunderstorms will
make inter-island travel hazardous and potentially dangerous at times
through the week. A Small Craft Advisory has been issued for Yap
with winds around 25 kt and seas pushing just sight of the hazardous
levels of 10 feet expected Wednesday night through Saturday
afternoon. Conditions could deteriorate sooner depending on were
90W`s circulation consolidates and any changes to it overall
movement. For Chuuk, with convection consolidating more around 90W,
showers have become isolated across Chuuk Lagoon with winds shifting
towards the east. Western Chuuk State is still on the eastern edge of
the heavy showers and thunderstorms around 90W, but conditions are
expected to improve as 90W moves in a northwest direction. Chuuk will
trend drier through Wednesday night, but models suggest convergent
east to southeast flow will develop over Chuuk Lagoon Thursday,
increasing showers up to scattered through late week. Surf will be
elevated across Yap State into Chuuk State due to the background
westerly swell from the monsoon pattern and swell being generated
from Invest 90W. Elevated surf, along with elevated King Tides around
the full moon on Wednesday, may lead to minor splashup/runup on
beaches, mainly along south and west facing shores, and potentially
expanding to north facing reefs of Yap.

For Palau, satellite shows mostly cloudy skies and isolated showers
and thunderstorms around Palau and extending back towards 130E, with
westerly winds around 10 to 15 kt. The current forecast for 90W keeps
most of the highest winds and seas between Yap and the Marianas,
especially as 90W consolidates through Thursday, but models suggest
the monsoon flow south of 90W will strengthen late this week or
weekend potentially pushing winds up to 22 knots and sea just below
10 feet, the hazardous thresholds for a Small Craft Advisory. Also,
there is also the potential for choppy seas and gusty showers and
thunderstorms to develop across Palau over the next few days within
the monsoon flow, and as 90W begins to generate a swell that will
impact the region. The full moon will occur Wednesday night, so tides
will be elevated (King Tides) over the next few days. This could lead
to minor splashup/runup if surf builds higher and faster than
expected.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...Flood Watch through Friday afternoon for GUZ001.

     High Rip Current Risk through Friday afternoon for GUZ001.

     High Surf Advisory until 4 PM ChST Friday for GUZ001.

MP...Flood Watch through Friday afternoon for MPZ001.

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

     High Surf Advisory until 4 PM ChST Friday for MPZ001>003.

Marianas Waters...Small Craft Advisory until 4 PM ChST Friday for PMZ151-152.

&&

$$


West Micronesia/Tropical Update: DeCou
Marianas/East Micronesia/Tropical Update: Williams
Marianas: Bowsher
East Micronesia: Doll
West Micronesia: Schank