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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-NORTHWEST AND APPROACHING ALAMAGAN FROM THE EAST-SOUTHEAST...
.NEW INFORMATION... A Tropical Storm Warning has been issued for Agrihan in the CNMI. A Typhoon Watch has been issued for Agrihan in the CNMI.
.AREAS AFFECTED... This local statement provides important information and recommended actions for people in the Northern Marianas.
.WATCHES/WARNINGS... A Tropical Storm Warning has been issued for Agrihan in the CNMI. A Typhoon Watch has been issued for Agrihan in the CNMI. A Tropical Storm Warning remains in effect for Tinian, Saipan, Alamagan and Pagan in the CNMI. A Typhoon Watch remains in effect for Alamagan and Pagan in the CNMI.
A Tropical Storm Watch means that tropical storm conditions, including winds of 39 to 73 mph, are possible within 48 hours. 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.
All persons in the Watch areas should review their preparedness plan and begin to take actions to prepare for conditions as indicated by your local forecast and additional details, below, for your island.
.STORM INFORMATION... At 2 PM ChST, the center of Tropical Storm Choi-wan (26W) was located near latitude 16.8N, longitude 147.5E. This was about 290 miles northeast of Guam. Choi-wan is estimated to be moving west-northwest at 18 mph, to then slow down to less than 10 mph tonight. The current forecast speed is likely to be a result of a center position being farther west than the prior forecast, skewing the forward speed higher during this cycle. Storm intensity was 45 mph. Choi-wan is forecast to intensify through tonight, possibly becoming a typhoon Friday afternoon.
.SITUATION OVERVIEW... Tropical Storm Choi-wan (26W) has increased in forward speed to then once again slow down later tonight, with a slight contraction in the tropical storm-force wind field expected to the west and southwest, but remain well within Tinian, Saipan and their adjacent waters as Choi-wan comes closer. As such, the Tropical Storm Watch was upgraded to Tropical Storm Warning for Agrihan, and a new Typhoon Watch issued as well. Choi-wan will continue west through tonight, making a turn to the northwest Friday morning as it begins to approach Alamagan from the south and intensify into a typhoon sometime Friday afternoon, turning sharply northward, to then move north- northeastward late Friday night. This forecasted passage 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 beginning this evening and continuing into Sunday afternoon. As Choi-wan is forecast to strengthen to a typhoon, there is likelihood 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 and Pagan.
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.
Take small loose object indoors. Identify suitable shelter. Stock up a few days worth of food and water. If no concrete shelter is available, look for a cave or something similar. Take action to protect food crops or other possessions as appropriate.
.WIND INFORMATION... Northerly winds of 10 to 15 mph will turn toward the northeast, then southeast and increase through Friday as Choi-wan moves into the northern CNMI and strengthens, potentially becoming a typhoon Friday afternoon as it approaches Agrihan from the south-southwest. Tropical storm force winds of 39 to 50 mph may begin by Friday. 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 now look to remain just west of Agrihan at this time.
.COASTAL INUNDATION AND SURF INFORMATION... Surf will initially build to 8 to 11 feet along east-facing reefs through Friday morning, then spread along north and west-facing reefs as the center moves north-northeast through 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 hazardous during the weekend and then 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 8 to 14 inches by early Monday morning, with up to 20 inches of rainfall possible near the center of the system.
Take small loose object indoors. Identify suitable shelter. Stock up a few days worth of food and water. If no concrete shelter is available, look for a cave or something similar. Take action to protect food crops or other possessions as appropriate.
.WIND INFORMATION... Northerly winds of 10 to 15 mph will turn toward the northeast, then southeast and increase through Friday as Choi-wan moves into the northern CNMI and strengthens, potentially becoming a typhoon Friday afternoon as it approaches Alamagan and Pagan from the south- southwest. Tropical storm force winds of 39 to 50 mph may begin by Friday. 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 11 feet along east-facing reefs through Friday morning, then spread along north and west-facing reefs as the center moves north-northeast through 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 hazardous during the weekend and then 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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