Area Forecast Discussion

Marianas Synopsis

Partly cloudy skies with just a few, light showers continue to cross the area. The northwesterly swell has diminished from distant and weakening Typhoon In-fa. looking ahead, a tropical disturbance may develop and head towards the far northern CNMI this weekend.

Discussion

The weather continues to remain quiet across the region, and this looks to continue through Friday morning. Then, a disturbance along a trough southwest of Wake Island may allow a low-level circulation to develop, with guidance indicating a potential tropical system of some sort (it may just be an Invest, or it may be something a little stronger),looks to pass through the far northern CNMI. As it approaches and crosses this region, a strengthening southwesterly wind may bring some breezy conditions along with scattered showers and maybe a thunderstorm or two to Tinian and Saipan, with the weather getting wetter the farther north you go.

As for Guam and Rota, isolated showers is all we can look for through the weekend, especially with our nocturnal "bump" at night, when shower coverage is a little more. The tropical disturbance also may increase winds some for Friday into the weekend, with breezy conditions possible for the higher terrain in southern Guam. otherwise, the weather looks to remain fairly tame through the weekend.

Tropical Systems

Typhoon In-fa is located near 24.8N 138.4E late this afternoon, about 180 miles west of Iwo To. In-fa is moving to the north around 7 miles per hour and is expected to take a slight turn to the north- northeast as it increases in forward speed through Thursday. Maximum sustained winds remain unchanged from this morning, coming in at 100 miles per hour. The typhoon is expected to weaken through tonight. Typhoon force winds extend outward from the center up to 50 miles. Tropical storm force winds extend outward from the center up to 125 miles.

For more information on Typhoon In-fa please refer to the Tropical Cyclone Public Advisory, issued by the National Weather Service, under WMO header WTPQ31 PGUM, or the Tropical Cyclone Warning, issued by the Joint Typhoon Warning Center, under WMO header WTPN31 PGTW.

Eastern Micronesia

A monsoon-like trough blankets eastern Micronesia this afternoon with satellite imagery showing isolated to scattered showers in the vicinity of the trough. Convergence near the trough will continue to promote periods of scattered showers at all forecast points for the next several days, though shower chances should only top out around 40 percent through the weekend. An isolated thunderstorm or two will also be possible, particularly at Kosrae during the next day or two. Winds will generally remain light to gentle winds at all forecast points through the forecast period. Combined seas of 4 to 6 feet will continue through much of the period with seas dominated by a persistent northeast swell for all locations.

Western Micronesia

Swells from Typhoon In-fa are diminishing within Western Micronesia, so the High Surf Advisory is being allowed to expire. Surf will remain fairly consistent now for the next several days for all the marine zones of Western Micronesia.

The monsoon pattern has largely broken down across Western Micronesia. It could easily rebuild once the Madden-Julian Oscillation comes back around, but for the next week or two conditions will likely tend toward the more sedate side. For Chuuk, just isolated showers through Friday night, then a slight chance of thunderstorms will add in for the weekend. For Yap and Palau, just isolated showers through Saturday night, then a slight chance of thunderstorms will add in for Sunday and Monday. The only exception will be at Palau where showers could increase to chance/scattered coverage for Sunday.

Winds and seas will be 5 to 10 knots and 6 feet or less respectively. This will lead to a continuation of benign marine conditions for the forecast period, which extends through Monday.

GUM WATCHES / WARNINGS / ADVISORIES

GU...None. MP...None. Marianas Waters...None.