Headline:
Tropical Storm Warning issued October 2 at 8:21AM ChST by NWS Tiyan GU
Event:
Tropical Storm Warning
Urgency:
Immediate
Effective:
October 1, 2026 - 3:21pm
Expires:
October 1, 2026 - 10:00pm
Description:
...TROPICAL STORM CHOI-WAN MOVING WEST-NORTHWEST AND AWAY FROM
ANATAHAN...
.NEW INFORMATION...
None.
.AREAS AFFECTED...
This local statement provides information and recommended actions
for people on Saipan, Tinian, Agrihan, Pagan and Alamagan in the
Commonwealth of the Northern Marianas.
.WATCHES/WARNINGS...
A Tropical Storm Warning remains in effect for Saipan, Tinian and
their adjacent coastal waters, as well as Alamagan, Pagan, and
Agrihan in the CNMI. A Typhoon Watch remains in effect for Alamagan,
Pagan, and Agrihan in the CNMI.
A Typhoon Watch means that typhoon conditions, including winds of 74
mph or more, are possible within 48 hours.
A Tropical Storm Warning means that tropical storm conditions are
expected within 24 hours.
A Flood Watch remains in effect for Tinian and Saipan. Please listen
closely for any Flash Flood Warnings that might be in effect for
your area.
Please check the latest public and marine forecasts for detailed
information about additional hazards.
.STORM INFORMATION...
At 7 AM ChST, the center of Tropical Storm Choi-wan (26W) was located
near latitude 17.0N and longitude 144.9E. This was about 140 miles
north-northwest of Saipan. Storm motion was west-northwest, 285
degrees, at 9 mph. Storm intensity was 60 mph. It is expected to
make a turn toward the north with a slight decrease in forward speed
through Saturday as it moves nearly parallel to the Mariana chain
once it becomes a typhoon sometime this afternoon.
.SITUATION OVERVIEW...
Tropical Storm Choi-wan has recently passed Anatahan, with the center
around 70 miles to the northwest. Choi-Wan is expected to slow
slightly as it continues westward, gradually turning to the north-
northeast late tonight through Saturday. As Choi-wan pivots, the
wind field will continue to expand, bringing other islands such as
Guam and Rota under occasionally near-gale winds during peak
conditions later this afternoon, as multiple rainbands continue to
drag south. Meanwhile Saipan and Tinian may be under a lull in
showers the next hour or two, intense convective lines will move in
once again before noon, continuing stronger TS conditions for the
weekend.
The most recent forecast track continues to indicate a movement along
the axis of the far northern Marianas, prolonging the duration of
damaging winds across the northern islands, likely maintaining
damaging to destructive tropical storm conditions for a lengthy
period of time continuing into Sunday afternoon. As Choi-wan is
forecast to strengthen to a typhoon, there is a possibility for
typhoon-force conditions to develop somewhere along the far northern
Marianas. As such, a Typhoon Watch and Tropical Storm Warning remain
in effect for Alamagan, Pagan, and Agrihan.
Instruction:
Stay indoors during heavy rain and tropical storm-force wind
conditions associated with Tropical Storm Choi-wan (26W). Heed the
advice of your local emergency managers and officials, and
continue to monitor forecasts by the National Weather Service
office in Tiyan, Guam. Remain in sturdy shelter until the all-
clear is given.
Preparations for Tropical Storm Choi-wan should be complete, or
rapidly rushed to completion. Take small loose object indoors.
Remain in suitable shelter, such as a cave or sturdy concrete
structure. Shelter in place until the all-clear is given.
.WIND INFORMATION...
North to northeast winds of 25 to 35 mph will turn toward the
southeast and increase today as Choi-wan moves west across the
northern CNMI and strengthens, potentially becoming a typhoon this
afternoon to the west of Alamagan and Pagan as it turns to the
north. Tropical storm force winds of 39 to 50 mph look to continue
through Sunday. Depending on the track and intensity, winds may
increase to strong tropical storm-force of 58 to 65 mph early
Saturday morning. Typhoon force winds greater than 74 mph look to
remain possible during closest passage.
.COASTAL INUNDATION AND SURF INFORMATION...
Hazardous surf of 8 to 12 feet along east-facing reefs are expected
this morning, to then spread along north and west-facing reefs as
the center moves north-northeast parallel to the northern CNMI
tonight through Saturday night, increasing by several feet during
this time. As Choi-wan continues to strengthen, surf will continue
to increase, likely becoming dangerous by early next week.
Significant coastal erosion and some coastal inundation is expected
during Choi-wan's passage.
.OTHER STORM EFFECTS...
Periods of rain, widespread heavy showers and scattered thunderstorms
are expected later today, which is expected to produce rainfall
totals of 8 to 14 inches by early Monday morning, with up to 20 inches
of rainfall possible near the center of the system.
Area Description:
Tinian; Saipan
Forcast Office:
NWS Tiyan GU
Sender:
w-nws.webmaster@noaa.gov