textproduct: Seattle/Tacoma

SYNOPSIS

An upper level ridge will remain situated over the region today with onshore flow continuing in the low levels. A weak frontal system will move over the area Friday into Saturday, bringing a slight chance of showers to the Pacific coast. An upper level ridge will rebuild over the area this weekend and will influence the area into early next week, leading to a gradual warm up across western Washington. Some light showers will be possible around midweek as some weak systems approach the region.

SHORT TERM /TODAY THROUGH SATURDAY/

Satellite imagery shows stratus remaining draped across the interior early this morning. With the cloud cover stuck in place, morning lows will likely remain a bit warmer than originally forecast- and look to only dip into the mid 40s to low 50s.

An upper level ridge will remain situated over the region today while onshore flow continues in the low levels. Onshore flow will help keep stratus around throughout the morning hours, but guidance does indicate some scattering is expected by this afternoon. As a result, expect afternoon highs to be a bit warmer than yesterday, with areas across the interior topping out in the mid 60s to near 70, while areas along the coast look to remain in the 50s to low 60s. The status of the stratus scattering will bear watching though, as it will have a direct impact on the day's temperatures.

A weak, dissipating frontal system will then approach the area on Friday as the ridge axis pushes inland and makes way for a shortwave trough. While the majority of the area looks to remain dry, this system may bring some light shower activity to the coast by Friday evening. The more notable impact from this system will be the uptick in onshore flow and the increased cloudiness across the area. Afternoon highs as a result will be in the 50s to mid 60s.

An upper level ridge will then rebuild over the region on Saturday, allowing for the gradual warm up to commence across western Washington. Highs on Saturday will warm into the low to mid 70s across the interior and into the mid 60s along the coast. Areas of Minor HeatRisk will expand across western Washington, becoming more widespread.

LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/

Ensemble guidance remains in good agreement that the upper level ridge will remain situated over the Western US into early next week, but will gradually push inland. As the ridge moves eastward, it may open the door to some additional rounds of light precipitation early in the week as weak systems brush by to the north. Overall, however, expect conditions to remain largely dry and warm across the area, with temperatures expected to climb back up into the mid to upper 70s by Tuesday. Some spots may even get close to 80 across the Southwest Interior.

Ensemble solutions start to diverge again closer to midweek, as the ridge pushes further inland towards the Great Plains and an upper level trough looks to swing into British Columbia. Temperatures look to remain warm, but the upper trough may start to reintroduce some light precipitation chances to portions of the area.

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AVIATION

Northwesterly flow aloft as upper level ridging remains offshore western Washington. A mixed bag of ceilings early this morning between MVFR/VFR as onshore flow maintains stratus deck over the area. We'll continue to see some ceilings lower locally to IFR with MVFR continuing throughout this morning for most areas. Flow will start to weaken this afternoon which will help low clouds lift and scatter (20z-23z) and provide a gradual return to VFR for all terminals.

KSEA...A mix between MVFR to VFR early this morning as low clouds remain around the terminal. Latest guidance shows a 15% chance of brief IFR conditions this morning (12z-15z). Otherwise, conditions will start to improve after 20z with a return to VFR expected by late afternoon. Winds remain S/SW up to 5 to 10 knots.

MARINE

Surface high pressure remains offshore allowing for low level onshore flow to continue. Steep seas persist early this morning (8 to 10 feet), more notably over the northern most coastal water zone where a Small Craft Advisory remains. Seas will decrease later this morning. Winds will continue to weaken this morning through the Strait of Juan De Fuca with onshore flow weakening as well.

A weak front will cross over the waters on Friday, with generally benign marine conditions. Onshore flow increases over the weekend allowing for more stronger pushes down the Strait.

Mazurkiewicz

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...Small Craft Advisory until 5 AM PDT early this morning for Central U.S. Waters Strait Of Juan De Fuca-Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From Cape Flattery To James Island Out 10 Nm.