Headline:
Tropical Storm Warning issued October 2 at 3:34AM ChST by NWS Tiyan GU
Event:
Tropical Storm Warning
Urgency:
Immediate
Effective:
October 1, 2026 - 10:34am
Expires:
October 1, 2026 - 6:45pm
Description:
...TROPICAL STORM CHOI-WAN MOVING WEST THROUGH THE NORTHERN
MARIANAS, SOUTH OF ALAMAGAN...
.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 Tinian, Saipan, and
adjacent coastal waters.
A Tropical Storm Warning remains in effect for 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 2 AM ChST...the center of Tropical Storm Choi-wan (26W) was
located near latitude 16.6N...longitude 145.5E. This was about
75 miles south of Alamagan, 105 miles north of Saipan, 105 miles
south of Pagan, and 220 miles north-northeast of Guam. Storm
motion was west, 260 degrees, at 12 mph. Storm intensity was 60
mph.
.SITUATION OVERVIEW...
Tropical Storm Choi-Wan is expected to slow slightly as it
continues westward early this morning, passing to the south of
Alamagan. Choi-wan is then expected to make a turn toward the
northwest, then north with a decrease in forward speed through
Friday. Then, Choi-wan looks to gradually turn to the north-
northeast late Friday night through Saturday after it emerges west
of the northern islands. Choi-wan is forecast to intensify
through Saturday, potentially becoming a typhoon Friday afternoon
or evening.
This forecasted track moving roughly along the axis of the far
northern Marianas is still expected to prolong 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. The
latest forecast track has shifted Choi-Wan farther west of the
islands, slightly decreasing this possibility.
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
Friday night 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...
Surf will initially build to 8 to 12 feet along east-facing reefs
through Friday morning, then spread along north and west-facing
reefs as the center moves north-northeast west of the northern
CNMI Friday night 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
could produce rainfall totals of 10 to 16 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