textproduct: Seattle/Tacoma

SYNOPSIS

Upper level trough moving out to the northeast today. Upper level ridge building over the area beginning tonight with the ridge remaining in place through Wednesday. Ridge weakens Wednesday night with the remnants of what is now tropical storm Elida approaching the area Thursday and Friday. Elida remnants weakening into an upper level trough offshore Saturday.

SHORT TERM /TODAY THROUGH TUESDAY/

Satellite imagery shows stratus along the coast, through the Strait of Juan de Fuca to near Whidbey Island, and through the Lower Chehalis Valley to near Shelton at 3 am/10z. Mostly clear skies over the remainder of the area. Temperatures in the 50s and lower 60s.

Upper level trough moving off to the northeast today. Weak onshore flow this morning becoming light this afternoon. Like Saturday morning the marine layer is shallow, around 1000 feet thick. The combination of the trough moving out, low level flow turning light and July sunshine will dissipate the marine layer late morning/early afternoon leaving sunny skies across the area. Highs a little warmer than Saturday, mid 60s to lower 70s coast and 70s to lower 80s inland.

Upper level ridge, centered well to the southeast, will begin building over Western Washington tonight. Light flow in the lower levels will keep the shallow marine layer along the coast. Lows in the 50s.

Upper level ridge remaining over Western Washington Monday and Tuesday. 500 mb heights in the mid to upper 580 dms. Flow aloft southwesterly which will send some high level clouds across the area at times. In the lower levels, flow going northerly. Unfortunately this change in the low level flow will pull smoke from the wildfires in Canada down over at least the northern portion of Western Washington beginning Monday afternoon. Smoke remaining over the area through Tuesday. Right now the smoke looks to be thick enough over the Northwest Interior to knock a few degrees off the high temperatures especially Tuesday. Highs Monday in the 70s along the coast and mid 70s to near 90 over the interior. Highs a couple of degrees warmer over the interior Tuesday with 80s to mid 90s while the coast stays in the 70s. Lows in the mid 50s to mid 60s.

Minor to moderate HeatRisk for the interior Monday. Moderate HeatRisk Tuesday with a pocket of major HeatRisk from Southern Snohomish county away from the Puget Sound over to Gold Bar down to around Mount Rainier and back up to near Tacoma. A heat advisory may be needed for this area Tuesday. Felton

LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/

Little change Tuesday night into Wednesday with the upper level ridge over the area, southwesterly flow aloft and light northerly flow in the lower levels. One more very warm day Wednesday with highs similar to Tuesday. Smoke most likely continuing over at least the northern portion of the area.

As should be expected the models are having trouble with the remnants of tropical storm Elida. The 00z run is much faster with the northward movement of the remnants putting a weak low off the coast Wednesday night into Thursday. More than enough of the ensemble solutions have a feature spinning out of the low that produces at least a slight chance of showers for most of the lowlands as well as the Olympics Thursday morning. Low sitting off the coast Thursday night into Friday before weakening into a trough Saturday. Another slight chance of showers for some locations Saturday morning. Low level flow turning onshore Wednesday night with a marine push Thursday lowering temperatures by at least 5 to 10 degrees versus the highs Wednesday. If we do end up getting some convection in the morning highs will be even cooler. With the lack of consistency in the solutions Friday and Saturday have once again tilted the forecast towards climatology with highs back down into the 70s for the interior and mid 60s for the coast.

There is a chance for another pocket of major HeatRisk over the Central Sound Wednesday. HeatRisk easing Thursday into the weekend. Felton

AVIATION

Westerly flow aloft continues today. IFR stratus along the coast will extend inland to areas mainly west of Puget Sound this morning before burning back to the coast by midday. Otherwise, VFR conditions will prevail. IFR/LIFR stratus will return to the immediate coast again Monday morning with VFR continuing for interior areas.

KSEA...VFR. Surface winds northerly 6 to 10 knots.

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MARINE

High pressure will remain centered offshore with lower pressure inland into midweek for varying degrees of onshore flow. Onshore gradients will ease through the early part of the week as thermally-induced low pressure develops across Western Washington and Oregon. Stronger onshore flow and pushes down the Strait look to resume in the latter half of the week as the thermal trough shifts eastward.

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FIRE WEATHER

Another period of hot and dry weather will increase fire weather concerns beginning Monday. Temperatures climbing back into the 80s and low 90s with minimum relative humidity values dropping below 30 percent in the afternoons Monday through Wednesday. Brief spells of low level offshore flow are possible in this window which would help to dry out the environment and make fuels more receptive. Beyond Wednesday, the pattern will need to be monitored as there is a suggestion of another influx of monsoonal moisture that could lead to another round of convection Thursday into the weekend. Felton

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-East Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory until 5 AM PDT Monday 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.