Area Forecast Discussion
Issued by NWS Tiyan, Guam
Issued by NWS Tiyan, Guam
450 FXPQ50 PGUM 220608 AFDGUM Area Forecast Discussion National Weather Service Tiyan GU 408 PM ChST Sat Mar 22 2025 .Marianas Synopsis... Gentle to moderate trades prevail. Satellite imagery and Doppler radar indicate high-level cirrus filaments present over the region. The buoys indicate seas of 5 to 7 feet. && .Discussion... Little change has been made to the forecast. A minor surface trough is expected to bring low-end scattered showers Sunday, followed by mostly clear skies early next week. More trade troughs may be pushed down by a passing subtropical high to the north, allowing a slight uptick in showers sometime in the second half of next week. && .Marine... Combined seas of 6 to 8 feet will persist the next few days, before tapering down a few feet by early next week as trade swell and northerly swell weaken. A moderate risk of rip currents is expected along north and east facing reefs for at least the next several days, and along west facing reefs through tonight. Surf will continue to diminish along all reefs, as trade swell and northerly swell weaken. && .Eastern Micronesia... Dry conditions will continue across eastern Micronesia for the next few days. Around the middle of next week, models continue to predict the development of a band of convergence over the region, possibly an Inter-Tropical Convergence Zone (ITCZ). The main area of convergence looks to develop and remain south of Pohnpei and Majuro, with both locations being on the northern periphery of the convection. POPs (Probability of Precipitation) look to remain in the 30 to 40 percent range for Majuro and around 30 percent for Pohnpei. Kosrae looks to sit right in the middle of the strongest convergence, resulting in POPs getting a bit higher. Due to the uncertainty of this pattern developing and actual location, kept POPs between 30 and 50 percent at Kosrae. Regardless, rainfall does not look to be real impressive. By the end of next week, a drier pattern appears likely over the Marshalls. Marine conditions look to remain relatively unchanged through the remainder of the weekend, with seas remaining in the 7 to 9 foot range at all locations. Seas are then expected to begin to subside Monday due to decreasing northerly and trade-wind swells. Seas should drop to around 4 to 6 feet by the middle of next week. Moderate to fresh winds look to subside as well, dropping to gentle to moderate around the middle of next week. && .Western Micronesia... A broad trough and embedded disturbance in southern and western Chuuk State remains poorly organized and has weakened over the last 24 hours. An ASCAT pass over the feature shows weak signs of westerly flow into the disturbance and satellite and model trends support that this will continue to open up into a trough and slowly propagate westward. Still, showers and widespread cloudiness remain across much of Chuuk State, including Chuuk Lagoon and southwestern waters. Around midnight, we anticipate showers to decrease as convergence weakens over Chuuk State and the feature progresses into eastern Yap State. Farther west, only spotty showers are currently over the main islands of Palau and Yap. Model guidance shows a disturbance embedded in the Near-Equatorial Trough (NET). Although this develops well southwest of the forecast locations, trailing convergence will influence Yap and Palau weather over the next few days. Additionally, the aforementioned trough near Chuuk is expected to interact with the NET, bringing scattered to numerous showers to Yap starting Sunday night, then to Palau starting Monday night. Starting around the middle of next week, trade-wind convergence strengthens across the region, keeping scattered showers in the forecast for Palau and Chuuk, but relatively quiet conditions are expect at Yap, being north of the pattern. Altimetry and buoy data show combined seas of 5 to 7 feet at Yap and Palau and up to 8 feet near Chuuk. Seas are expected to decrease by one to two feet next week in response to slight decreases in easterly trade swell and background northerly swell. Winds will generally be light to moderate for Palau and gentle to moderate across Yap, with winds increasing to moderate to fresh Monday through Tuesday at Yap. For Chuuk, winds remain moderate to fresh over the next several days. && .GUM WATCHES/WARNINGS/ADVISORIES... GU...None. MP...None. Marianas Waters...None. && $$ Marianas: Montvila East Micronesia: Kleeschulte West Micronesia: Cruz