Weather alerts for the NWS Guam area of responsibility

000
FXPQ50 PGUM 280742
AFDGUM

Area Forecast Discussion
National Weather Service Tiyan GU
542 PM ChST Wed Oct 28 2026

.Marianas Synopsis...
Light and variable winds are visible over Guam and Rota with moderate
easterlies over Tinian and Saipan. Radar and satellite imagery
indicate scattered showers for Tinian and Saipan, and island effect
showers for Guam and Rota. Model and observations indicate combined
seas of 4 to 7 feet.

&&

.Discussion...
A long elongated trough connecting all the way into Typhoon In-fa 
has weakened slightly from last night and is starting to drift south.
This feature is now expected to bring scattered showers and isolated
thunderstorms to Tinian and Saipan early tonight, Rota all night, 
and Guam by late tonight. Isolated showers will return once the 
trough has passed each island. Isolated showers will likely continue 
for much of the forecast period for Guam and Rota. Scattered showers 
and isolated thunderstorms may return Friday for Tinian and Saipan 
due to slightly closer proximity to In-fa as passes somewhere through
the far northern CNMI between Sarigan and Maug. Showers for Tinian 
and Saipan will likely return to isolated for the rest of the 
forecast period by Saturday. Current Typhoon In-Fa is expected to 
make it's closest point of approach midday Friday. Breezy conditions 
are possible for Tinian and Saipan Friday with frequent gusts of 30 
mph, particularly in thunderstorms. This situation will continue to 
be monitored closely for any potential changes. See the "Tropical 
Systems" section for more details.

&&

.Marine...
Gentle northeast winds will prevail across Tinian and Saipan through
at least tonight, while light winds prevail over Rota and Guam. 
Scattered showers and isolated thunderstorms will be possible for 
Tinian and Saipan early tonight, all night over Rota, and late 
tonight for Guam as a trough shifts south over the islands. Therefore,
there is moderate risk of lightning tonight for all islands.There 
will be a moderate risk of rip currents through the weekend for 
north- and east-facing reefs due to a primary east- northeast swell. 
Combined seas are expected to waver between 5 and 7 feet through 
Thursday. By late Thursday, seas are expected to increase 
significantly and become hazardous ahead of Typhoon In- Fa, which is 
anticipated to pass somewhere through the far northern CNMI between 
Sarigan and Maug island. Widespread seas of 11 to 14 feet are 
expected for Tinian and Saipan. Seas of 10+ feet are also possible 
for Guam and Rota.

&&

.Tropical Systems...
At 100 PM ChST, the center of Typhoon In-fa was located near 15.0N 
159.3E, or 560 miles north of Pohnpei, 910 miles east of Alamagan, or
about 975 miles east of Guam. Himawari visible satellite imagery 
this afternoon shows Typhoon In-fa with a well-developed eye around 
40 miles in width, with a burst of convection along the west to 
southwest edges of the eyewall. The outer rainbands are somewhat
patchy and discontinuous, displaced around 350 to 500 miles from the
center to the southwest, south, and north. In-fa remains a Category 
4 typhoon with maximum sustained winds at 140 mph, and is expected to
intensify tonight, possibly becoming a super typhoon by midnight with
maximum winds forecast to increase to 150 mph. Currently, In-fa is 
moving west-northwest at around 10 mph. It is expected to maintain 
this general course with an increase in forward speed through Friday 
morning as it makes a northwest turn toward the far northern 
Marianas. 

The latest forecast track from the Joint Typhoon Warning 
Center shows the center of In-fa tracking close to or over Agrihan 
Friday night as it turns slightly toward the northwest. As In-fa 
approaches the far northern Marianas, the threat of destructive winds
will increase through Friday evening, with the onset of damaging 
winds beginning as early as Friday afternoon. The current forecast 
track suggests that the threat for destructive typhoon-force winds 
will be highest for Agrihan and Pagan close to the center of Typhoon 
In-fa, but keep informed of possible changes to the forecast location
of the center. A Typhoon Watch is currently in effect for the 
islands of Alamagan, Pagan, and Agrihan in the northern CNMI.

For more information on Typhoon In-fa, please refer to bulletins 
from the Joint Typhoon Warning Center under WMO header WTPN31 PGTW
and from the National Weather Service under WMO header WTPQ31 
PGUM. 

&&

.Eastern Micronesia...
Despite Typhoon In-fa developing just north of the region, fairly
quiet conditions prevail across much of eastern Micronesia this 
afternoon. Kosrae and Majuro are situated within a broad surface 
ridge that is set up behind In-fa. Pohnpei can expect scattered 
showers over the next day or so as convergent westerlies to the south
of In-fa's passage set up nearby, but so far this afternoon, most of
the showers remain south of the island. Isolated showers will
continue near Majuro through Thursday night, increasing to scattered
Friday as the broad convergence boundary, and associated showers to 
its east, gradually shift westward into the area.

Recent buoy and altimetry data show combined seas of 4 to 6 feet,
comprised of a primary north to northeast swell and secondary
southeast swell. Winds will be light to moderate throughout the
forecast period, decreasing to mostly light by early next week as a
broad, weak, elongated trough sets up across the area.

&&

.Western Micronesia...
Light to gentle winds will persist through the forecast period, which
could allow island convection to develop from time to time at Palau 
during the late morning into afternoon hours. Yap, which typically 
doesn't see the "string and tail" of convection develop, had island 
convection today along western sides of the island, before tailing 
off in coverage over the open waters. This was due to a favorable 210
degrees wind direction aligning with the ~400-500 foot hills just 
north-northeast of the airport, which provided just enough 
orographic lift for the light, southwest ocean breeze to act on. With
Typhoon In-fa heading towards the far northern CNMI, this wind 
direction is expected to hold for another day or two, which may allow
for Yap to see additional island convection develop. However, 
spatial coverage of island convection at either location is 
sufficiently small enough to keep isolated shower coverage/20 percent
probabilities, but this will be monitored for more robust 
development.

Otherwise, isolated showers under light to gentle winds and seas of 
3 to 5 feet may increase a foot Friday into Saturday, as a north to 
northeasterly swell from In-fa arrives.

&&

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

$$

Marianas: Ogle
East Micronesia/Tropical Systems: DeCou 
West Micronesia: Doll