Area Forecast Discussion
Issued by NWS Tiyan, Guam
Issued by NWS Tiyan, Guam
094 FXPQ50 PGUM 162007 AFDGUM Area Forecast Discussion National Weather Service Tiyan GU 607 AM ChST Fri May 17 2024 .Marianas Synopsis... Satellite shows patchy clouds and probably a few showers in the upstream flow, mainly approaching Guam but possibly skimming by Rota also. Fewer clouds were seen upstream from Tinian and Saipan. Local airports report gentle to moderate surface winds and combined seas are ranging from 5 to 8 feet, with the larger sets mainly toward the northeast. && .Discussion... Very little change was made to the forecast. A few more showers are expected for Guam and Rota today through this evening, and a gradual increase is atmospheric moisture is expected to arrive from southeast next week. Meanwhile, the pressure gradient will tighten between high pressure to our north and a tropical disturbance south of the Marianas this weekend into next week. && .Marine/Surf... A Small Craft Advisory may be needed by Monday. Moderate trade winds today will become fresh with stronger gusts this weekend. Combined seas of 5 to 8 feet will gradually build to 6 to 9 feet on Sunday. There will be a moderate risk of rip currents along east facing reefs through Saturday. The rip current risk will increase along north and east facing reefs by Sunday. Waves and surf will build by 1 to 3 feet later this weekend into early next week. There may be a high risk of rip currents along east facing reefs and a moderate risk along north reefs by Sunday. && .Tropical systems... Invest Area 93W was centered roughly near 5N140E overnight, and it remains a broad and weak circulation. A buffer circulation near the equator south of Chuuk may be supplying a west wind component that could help 93W further develop. Models differ significantly on the developments of 93W and people especially in western Chuuk State, Yap State, and The Republic of Palau should continue to monitor the latest forecasts. && .Fire Weather... Rainfall yesterday at Guam airport was 0.08 inch and the KBDI is up to 533 today; in the high category. The island terrain is relatively dry and winds could become gusty over the weekend, but a few passing showers are expected and humidity readings will likely remain above 60 percent. && .Eastern Micronesia... Only minor changes to the forecast were done over night. Most notably the increase in chance of showers for Pohnpei, they were increased from scattered to numerous for tonight. This is due to a weak disturbance to the southwest and the convergences of the Inter- Tropical Convergence Zone (ITCZ). As for Kosrae, showers are expected to remain in the forecast through most of the weekend with the worst of the showers happening tonight through Saturday. Showers are anticipated to start diminishing around Sunday. Majuro can expect to see scattered showers through out most of the forecast. The next drier period is anticipated to be the beginning of next week. Gentle to moderate winds are expected through the next several days. Altimetry shows combined seas of 5 to 7 feet with 7 feet near the RMI. There is a slight southerly swell coming from the southeast, however, this swell is not expected to be of much concern, but will be keeping a close eye on that swell. && .Western Micronesia... The near equatorial trough (NET), and the evolution of a potential tropical cyclone embedded in it, remains the focus for western Micronesia for the next several days. The NET stretches east- northeastward from near 5N130E to a weak circulation southeast of Yap and Palau, 93W, centered near 5N140E, then continues southeast to another circulation southeast of Chuuk near 3N153E. The strong convergence north of the trough and east of 93W, will generate scattered to widespread showers across Chuuk and their waters that look to continue into the weekend, possibly into next week. Locally heavy showers are a possibility, along with isolated thunderstorms. A trade trough along the north side of the NET is passing through Yap currently and towards Palau. Scattered showers and isolated thunderstorms expected for Palau through Saturday, this trough was widened a bit to include Yap. However, though this could change any day when the NET actually begins to move back northward with the approach of a possible TC, which the general trend is hinting at. Have bumped up of shower and thunderstorm potential for Yap starting Tuesday. Invest 93W looks to meander between Yap and Chuuk through the weekend, with another circulation southeast of Chuuk approaching from the east. The general model trend is for a tropical cyclone (TC) to develop around early next week between Yap and Chuuk and meander off to the northwest in the general direction of between Yap and Palau. Depending on the track and intensity of the potential TC, shower and thunderstorm coverage could increase for all three locations. Palau will see combined seas of 2 to 4 feet over the next several days, along with generally gentle winds. Seas of 4 to 6 feet and gentle to moderate winds are on tap for Yap and Chuuk. Depending on the track and intensity of the potential TC, seas and winds could increase significantly for all three locations. && .GUM WATCHES/WARNINGS/ADVISORIES... GU...None. MP...None. Marianas Waters...None. && $$ Marianas: Simpson Micronesia: Bowsher