textproduct: Seattle/Tacoma

SYNOPSIS

Dry and cool conditions are expected Friday with weak upper level high pressure building across Western Washington. The next upper low moves south offshore of the west coast this weekend, with just a weak front clipping the local area. This brings much warmer temperatures across the area this weekend through early next week.

SHORT TERM /TODAY THROUGH SUNDAY/

No major forecast updates have been made this morning, and the frost advisory has been allowed to expire. See below for the previous discussion and an update to the aviation section.

A ridge will build Saturday over the east Pacific Ocean, moving ashore during the day, and into Sunday. A small trough within this ridge is expected to dissipate per the ensembles. Saturday will be a near copycat to Friday, with morning clouds being a bit more widespread, and warmer overnight temperatures. The frost impacts are expected to be minimal at this time, but a couple south interior places may see lows dip into the mid 30s Saturday morning. Highs Saturday will climb into the mid and upper 60s, with some doubt if the cloud coverage will hold more into the day and hinder the temperatures. Winds during this period will remain generally light at 5-10 mph between the south and north.

Sunday will bring the next chance (40-50%) of showers to the coast as a large upper low digs southward over the Pacific Ocean. The remainder of the coverage area will stay dry Sunday with more clouds. Highs on Sunday will peak during the next 7 days, with highs potentially reaching the upper 60s to low 70s. This will linger into the early work week. Again, some doubt remains with the cloud coverage, but the building ridge and high pressure will warm up the region quite a bit. Average for this time of year is around 60 degrees.

HPR

LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/

As the weekend comes to an end, ensemble guidance remains in good agreement that the upper low to the southwest will make its way inland. For Monday, we'll continue to see Minor HeatRisk across the region with daytime highs around 70 degrees. This brings some potential for increased moisture to wrap around the upper low and bring precipitation chances to the region Tuesday and Wednesday. This will also usher a return to temperatures closer to normal values across the region. While there's a bit more spread in the ensemble guidance later in the week, a return to drier conditions is favored for midweek and beyond.

Cullen

AVIATION

Flow aloft remains northerly, with surface flow expected to turn for most terminals to the NE after 18Z. Pockets of SCT clouds remain across western Washington, but at this time, all terminals are VFR except for OLM which is MVFR due to lower cigs. Otherwise, expect a continuation of VFR cigs and light northerly flow throughout the TAF period.

KSEA...VFR conditions are expected throughout the TAF period, with pockets of SCT to FEW clouds. Winds are lightly southeasterly now, but are expected to turn more NE after 18Z at around 5 kts. After 21Z, expect northerly winds to increase to around 7 kts and last at that speed until 03Z before tapering back off. A light NE surface wind will persist throughout the rest of the period with VFR cigs.

MARINE

High pressure remains over the waters today, weakening into Saturday as the next low pressure system slides southward from the Gulf of Alaska. This low will remain offshore beyond the coastal waters this weekend into the start of next week, but an associated front will cross the waters on Saturday. This will bring a return of southerly winds over the waters, but this front won't be particularly strong with only a 30-40% chance of small craft gusts over the outer coastal waters (lower elsewhere). Expect seas to build to 6-7 ft over the coastal waters, largest beyond about 30 NM from shore where winds will be strongest. As a result, expect choppy conditions in these short period waves. A series of very strong ebb currents on the Grays Harbor bar can be expected during the early morning hours for the next several days.

Elsewhere and otherwise, not much in the way of impactful marine conditions expected through the early portion of next week. Another disturbance may bring stronger northwest winds to the coastal waters as well as seas approaching 10 ft closer to the middle of next week.

Cullen

HYDROLOGY

No river flooding is expected over the next 7 days.

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...None.