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Tropical Storm Warning
ActiveTinian; Saipan
Status
In Progress
Started about 2 hours ago
Ends
Issued
Severity
Severe
Urgency
Immediate
Certainty
Likely
Details
...TROPICAL STORM CHOI-WAN MOVING WEST INTO THE NORTHERN MARIANAS, SOUTHEAST 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 7 PM ChST, the center of Tropical Storm Choi-wan (26W) was located near latitude 17.0N, longitude 146.4E. This was about 55 miles southeast of Alamagan, 90 miles south-southeast of Pagan, and 260 miles north-northeast of Guam. Storm motion was west, 280 degrees, at 13 mph. Storm intensity was 45 mph.
.SITUATION OVERVIEW... Tropical Storm Choi-Wan is expected to slow slightly as it continues westward overnight, with the center passing to the south of Alamagan early Friday morning. It 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 on Saturday after it emerges west of the northern islands. Choi-wan is forecast to intensify through Friday, potentially becoming a typhoon late Friday night or early Saturday morning.
This forecasted passage moving along the axis of the far northern Marianas is still expected to prolong the duration of damaging winds across the northern islands, likely leading to a lengthy period of time of damaging to destructive tropical storm conditions 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.
Instructions
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. If no concrete shelter is available, look for a cave or something similar. Shelter in place until the all-clear is given.
.WIND INFORMATION... North to northeast winds of 15 to 25 mph will turn toward the southeast and increase through Friday 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.
Data from the National Weather Service
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