textproduct: Seattle/Tacoma

SYNOPSIS

Weak broad upper level trough over the area along with low level onshore flow through Friday. This combination will produce mostly cloudy and cool conditions with a chance for light showers mainly over the mountains and along the north coast. Drier conditions and a small warming trend over the holiday weekend into early next week as the flow aloft becomes first more zonal then southwesterly Monday. Temperatures will return closer to normal with more sunshine.

SHORT TERM /TODAY THROUGH FRIDAY/

No major changes to the forecast this morning. Satellite imagery depicts widespread stratus overcast across the lowlands and coast. This layer does not appear not as deep as observed yesterday morning and reports of drizzle have been less widespread. Think today will have a better shot at scattering out during the afternoon but overall will be similar to the past couple of days.

Small changes Thursday night into Friday with a weak front dissipating off the north coast. 500 mb heights rising behind the front getting up into the mid to upper 570 dms by 00z Saturday. Low level onshore flow decreasing leading to a thinner marine layer and more sunshine in the afternoon. Highs Friday in the 60s and lower 70s. Lows in the 50s.

June 2026 will go into the books as the 7th warmest in 82 years of records at Seattle-Tacoma airport. The average monthly temperature was 64.0 degrees ( 1.9 degrees above normal ). Even with only 5 days with measurable rain ( the normal is 9 days ) the monthly rain total of 1.34 inches was just 0.11 inches below normal. The number of days with measurable precipitation for Seattle the first half of the year was 68. This is tied for the 4th lowest in the January through June time frame and 19 days below the normal of 87 days. In 2025 Seattle had only 132 days with measurable precipitation. The 6th lowest yearly total at Seattle-Tacoma airport and 24 days less than the normal of 156 days. Felton

LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/

Not much going on in the extended forecast. Models showing either weak trofiness or zonal flow aloft over Western Washington through the holiday weekend. 500 mb heights are in the mid 570 dms and low level onshore flow is light. End result is a couple of normal early July days with sunshine, especially in the afternoon. Highs in the upper 60s to mid 70s inland and mid 60s on the coast.

Small change for the first part of next week with the large upper level ridge over the Midwest extending back over the Rockies beginning to build northwest. Zonal flow aloft becoming southwesterly with 500 mb heights rising slightly. A touch warmer Monday and Tuesday with the warmest locations in the interior getting close to 80 while the rest of the interior remains in the 70s. Highs on the coast in the mid to upper 60s.

AVIATION

The northwesterly flow from an upper level trough continues through the TAF period. Widespread stratus persist this morning with MVFR ceilings within the 2,000 to 3,000 foot range. Improving conditions are expected in the afternoon with CIGS rising above 3,000 feet for most areas and skies trending scattered to broken. Stratus deck will return tonight with MVFR conditions resuming. South to southwest winds 5 to 10 kt will continue through the period.

KSEA...MVFR ceilings persist this morning. Ceilings will gradually improve to VFR this afternoon with clouds trending scattered to broken. MVFR conditions will return overnight and into Thursday morning. South to southwest winds 5 to 10 kt will continue through the TAF period.

MARINE

Broad high pressure will continue over the northeast Pacific with lower pressure inland. High pressure will weaken Thursday as a low moves towards the British Columbia coast with a weak front over the coastal waters. High pressure will rebuild later Friday and remain through the weekend.

Small craft advisory remains in effect for the outer coastal waters for choppy seas today ( 10 or 11 feet with a 9 second period ). Seas subsiding tonight.

Small craft advisory has been issued for the Central and Eastern Strait of Juan de Fuca with diurnally driven westerlies tonight. Small craft advisories are possible in the evenings over the weekend for the same reason. Felton

FIRE WEATHER

Little in the way of fire weather concerns in the week ahead. Upper level troughing maintaining cool and cloudy conditions with high relative humidity values and a slight chance for showers along the coast and mountains through Thursday. Drier, sunnier, and more seasonable temperatures will begin Friday continuing into early next week. Low level onshore flow will moderate daytime minimum RH values and bring in good RH recovery each night.

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Small Craft Advisory from 6 PM this evening to 2 AM PDT Thursday for Central U.S. Waters Strait Of Juan De Fuca- East Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory until 6 PM PDT this evening 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.