Seattle, Washington

Thunderstorms over the outer coastal waters this morning have continued to show signs of low-level rotation, and as a result, a couple Special Marine Warnings have been issued for potential waterspouts. While these storms continue to be short-lived, a brief waterspout well offshore cannot be ruled out as these storms continue. Convective activity will taper off by the mid afternoon as the upper low weakens and shifts inland.

In addition, fog remains well entrenched over the lowlands of Lewis and southern Thurston Counties, and a Dense Fog Advisory will continue for these areas through 11 AM. Otherwise, the remainder of the forecast remains on track this morning with no additional updates.

Drier conditions are expected over the weekend as an upper low offshore weakens and moves inland well to the south of the region. An upper level ridge moving into the region on Sunday will keep conditions dry and temperatures seasonable across western Washington into Monday. The first half of next week will remain mostly dry, with chances of precipitation increasing mid to late week as a series of systems approaches the Pacific Northwest.

An upper level low offshore will continue to bring showers and some isolated thunderstorms to the coastal waters through the early morning hours. Showers will gradually taper across the waters through the day as the low weakens and exits the area. Otherwise, expect cool conditions for areas across the interior this morning as skies continue to clear. Morning lows are expected to approach freezing for many areas south of the Sound, but particularly across the Chehalis River Valley. Areas of clearing have also started to see some fog development overnight, so could even see some spots of dense fog this morning. Morning temperatures will remain a couple degrees warmer for areas north of Seattle- however, with temperatures expected to dip into the mid 30s, could see some areas of frost development as well. Freeze warnings remain in effect for areas along the Chehalis River Valley and frost advisories remain in effect for areas north of Seattle and along the foothills of the Cascades through mid morning. Any areas of fog are expected to scatter by late morning.

Overall conditions will be drier today and Sunday as the low offshore exits the area and an upper level ridge moves into the region. Cool overnight lows in the 30s will bring areas of additional frost development to the area on Sunday morning and moisture in the low levels will likely promote another round of fog development. High temperatures will be in the low to mid 50s both days.

The upper level ridge axis will push further inland on Monday, maintaining mostly dry conditions for western Washington for the start of next week. A few ensemble members do continue to hint at a weak frontal system brushing the region, which may bring some light precipitation chances (roughly 20 to 30%) to the coast through the day. Morning lows will be in the 30s and afternoon highs will be in the low to mid 50s.

Conditions largely look to remain drier through the first part of next week, though a splitting system may bring some light rain to portions of the area on Tuesday. A return to a more unsettled pattern looks more favorable mid to late week as a series of systems approaches western Washington. At this time, a weak system looks to move across the area on Wednesday, with a stronger system on Friday looking to bring more notable chances of precipitation. However, it is worth noting that there still remains a decent spread amongst ensemble solutions for the second half of the week. Morning lows will be in the mid 30s to mid 40s and afternoon highs will be in the mid to upper 50s throughout the period.

14

Surface low pressure will continue to dig southward off the shore, with high pressure rebuilding in southern B.C. over the weekend. Showers with isolated thunderstorms will continue over the coastal waters through the morning. Dense fog continues across many of the terminals this morning, generally south of PAE. Expecting to see improvement after 18Z-20Z to VFR for impacted terminals. Additional fog/mist development tonight is likely, and may be more widespread in coverage in the Puget Sound/south interior for another chance of IFR/LIFR conditions. Light northerly winds around 5 kt or less increasing to 5-8 kt this afternoon.

KSEA...LIFR conditions this morning with fog impacting the terminal. Improvement to VFR expected after 18Z and in the worst case scenario by 20Z. Fog expected Sunday morning with LIFR conditions around 12Z. Light NE winds this morning becoming more N/NW this afternoon around 5-8 kt. Winds become NE this evening at 4-6 kt.

HPR/29

Showers continue to move across the coastal waters this morning. Rotation has been observed with these storms. Therefore, brief waterspouts cannot be ruled out.

A surface low will begin to dig southward across the waters today. High pressure will rebuild inland. This will lead to a brief window of offshore flow through the weekend, with gustier winds to 20 kt this morning in the coastal waters diminishing quickly. Shower and thunderstorm activity will continue in the coastal waters through the morning, but will wind down through the day. Hazardous winds are not expected at this time through Wednesday, when the next system passes through. Another system may also skirt the waters late next week/weekend.

Seas will hover at 4-6 ft through the weekend, but build back to 10 to 11 ft Monday as swells increase out of the west. Seas drop back down to 6-8 ft Tuesday through Thursday but build back to 10-14 ft late Thursday through next weekend.

HPR/29

WA

Frost Advisory until 9 AM PDT this morning for Downtown Everett / Marysville Area-Eastern Kitsap County-Eastern Strait of Juan de Fuca-Eastside-Foothills and Valleys of Central King County-Foothills and Valleys of Snohomish and Northern King Counties-Foothills and Valleys of the North Cascades-Lake Crescent Area Including US 101-Lowlands of Western Skagit and Northwestern Snohomish Counties-Lowlands of Western Whatcom County-Shoreline / Lynnwood / South Everett Area-Western Strait of Juan de Fuca.

Dense Fog Advisory until 11 AM PDT this morning for Lowlands of Lewis and Southern Thurston Counties-Olympia and Southern Puget Sound.

Freeze Warning until 9 AM PDT this morning for Lowlands of Lewis and Southern Thurston Counties-Middle Chehalis River Valley.

PZ

None.