textproduct: Seattle/Tacoma

SYNOPSIS

Dry weather into Sunday with weak ridging over the Pacific Northwest. Onshore flow will also increase over the weekend. A system on Monday will result in widespread rain and cooler temperatures. Unsettled conditions on Tuesday, with drier weather possible by midweek.

SHORT TERM /TODAY THROUGH MONDAY/

Stratus continues to push inland this morning across much of western Washington. Cloud thickness of around 1500 to 2000 ft indicate that it will likely take much of the day to clear out these clouds. Highs will likely get into the 60s to near 70, depending on how much we clear out today. Areas on the coast may not completely clear out today. Another round of stratus expected again tonight into Sunday morning with increasing onshore flow. Of note, west winds will increase this evening into tonight along the Strait of Juan de Fuca which may result in wind gusts along the immediate Strait and Whidbey Island reaching 30 to 35 MPH. Otherwise, highs both Saturday and Sunday will range in the 60s to mid 70s.

A frontal system will move onshore late Sunday night through Monday resulting in widespread rain and cooler conditions. Monday will also be rather breezy, with increasing southerly winds. At this time, wind gusts look to range 20 to 35 MPH for most of Western Washington. Probabilities for wind gusts reaching 40 MPH peak around Whidbey Islands (and northwards) as well as along the north coast, with probabilities from NBM ranging 40 to 60% on Monday. Although widespread impacts aren't expected with these winds, unsecured tents or outdoor equipment could be impacted. There is also a low chance (less than 15%) of thunder on Monday, mainly late Monday. Highs on Monday will only reach the mid 50s to mid 60s.

LONG TERM /MONDAY NIGHT THROUGH FRIDAY/

Unsettled conditions continue Monday night through Tuesday as the upper low moves southwards across the Pacific Northwest. Showers will be less widespread on Tuesday, mainly focused from Snohomish County southwards by the afternoon. High surf conditions may be possible on the coast Monday night into Tuesday as this system brings with it large waves. Waves peak in height early Tuesday before slowly easing throughout the day. The upper low will then become more situated over the Southwest midweek, with weak ridging building back into BC and the northern Pacific Northwest, resulting in generally drier conditions. Ensembles suggest another trough may begin to approach Western Washington by late next week. Cooler temperatures on Tuesday will warm back into the upper 60s to low 70s by midweek.

JD/62

AVIATION

Increased low level onshore flow in association with a weak system moving into British Columbia has allowed for stratus to fill in across the majority of the interior this morning. Ceilings as a result have largely lowered to LIFR and IFR across the interior terminals. Latest satellite trends still show stratus filling in across portions of the interior around 16Z. Given these recent trends and some additional high cloud cover moving in overhead, expect stratus to linger across the interior into the afternoon. While stratus is expected to lift through the morning hours, expect stratus not to scatter until 20-21Z for the interior areas. Stratus will linger along the coast through much of the day. Surface winds will be west/southwesterly and gusty at times for KBLI and KHQM between 15 to 25 kts. A brief switch of surface winds to the north will be possible for central Puget Sound terminals this afternoon into this evening, with winds generally expected to persist at 6 kt or less. Winds are then expected to shift back to the south late tonight into the overnight period.

KSEA...IFR cigs at the terminal in stratus this morning. Cigs will gradually lift through the morning hours, but will not scatter until around 20-21Z coinciding with improvement back to VFR conditions. Southwesterly surface winds are expected between 5-10 kt this morning. Winds may briefly switch to the north this afternoon and evening between 01-04Z, but should remain light at 6 kt or less. Winds will then switch back to the south late tonight and will remain light.

14

MARINE

Surface high pressure well offshore will result in continued onshore flow through the weekend. Onshore flow will peak Saturday night. A strong west push through the Strait of Juan de Fuca is expected this evening into tonight. For this reason, the Gale Watch has been upgraded to a Gale Warning. Frequent wind gusts to 35 kt are expected for the central and eastern Strait of Juan de Fuca during this period. SCA wind gusts are also forecast for Admiralty Inlet. Generally lighter winds on Sunday as high pressure weakens. A weather system will then move across the waters on Monday leading to increasing southerly winds. Widespread SCA winds are expected on Monday with this system for the majority of waters. Will also need to monitor the potential for gales for eastern Strait of Juan de Fuca on Monday. Weak ridging then returns Tuesday into midweek.

Seas will be 7 to 10 feet today with a dominant period of 8 to 9 seconds. Seas will briefly subside to 5 to 7 feet on Sunday. Seas will then build to 12 to 16 feet late Monday into Tuesday with the weather system before subsiding to near 10 feet on Wednesday. JD

HYDROLOGY

The daily hydrology discussion has ended until the start of the next rainy season; it will only be updated during this time as needed.

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Gale Warning from 2 PM this afternoon to 3 AM PDT Sunday for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory from 5 PM this afternoon to 3 AM PDT Sunday for Admiralty Inlet.

Small Craft Advisory until 2 AM PDT Sunday for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From James Island To Point Grenville 10 To 60 Nm- Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm.