The latest forecasts from the Joint Typhoon Warning Center (JTWC) and numerical guidance continues to strengthen Tropical Storm Choi-Wan (26W) as it crosses the Marianas sometime this weekend, possibly stalling or slowing to a crawl as it does so, becoming a typhoon by the end of the weekend. Choi-Wan is then forecast to turn north and accelerate somewhat during the early to middle portion of next week while it continues strengthening, possibly into a major typhoon.
As all of this occurs, the west to southwest monsoon flow already encompassing northern Palau (mainly near Koror) and western Yap State will continue strengthening, with sustained winds of 15 to 20 knots possible. Strong moisture pooling near the trough axis combined with at least decent surface convergence should foster increasing shower and thunderstorm coverage and intensity as we head into the weekend and early next week. Current indications are for 3 to 6 inches of rainfall, locally in excess of 8 inches being probable for northern Palau and western Yap State. This could lead to some minor flooding concerns and landslide potential, especially near Koror where the steeper terrain is juxtaposed with the strong moisture pooling and surface convergence.
As the winds increase, and Choi-Wan strengthens, seas and surf will also increase. This could lead to hazardous conditions for the northern reefs and potentially for small craft traversing the waters.
Residents across northern Palau and western Yap States are encouraged to continue to follow forecast trends at www.weather.gov/gum and on social media.