textproduct: Seattle/Tacoma

SYNOPSIS

A weak frontal system will clip the area tonight and into Sunday for increased cloud cover and cooler temperatures. Warming temperatures and high pressure return to the area early next week, with Tuesday likely to be the warmest day. It isn't long lived as more unsettled weather returns for the second half of next week.

SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/

An increase in cloud cover is apparent on visible satellite this afternoon as a weak frontal system nears the area. As it moves through tomorrow, cooler temperatures in the upper 60s will return under mostly cloudy skies. High pressure rebounds early next week and will generally square itself over the NW. Tuesday could see highs in the upper 70s to low 80s, with the warmest locations being eastern Grays Harbor County in through south King County. In these areas, there is greater than a 50% likelihood that Moderate HeatRisk levels could be achieved. That said, the models have struggled lately with resolving the extent of the marine layer influence and if that is to develop and linger, it could drop a few degrees off the expected highs.

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LONG TERM /TUESDAY THROUGH SATURDAY/

A cutoff low offshore of the OR/CA border will act to scoot the high pressure off to the east and bring in more southwesterly flow aloft. There is still considerable divergence in solutions via the ensembles regarding the depth of the low and its track. This will generally be the onset of a return of more unsettled weather. Zonal flow resumes about midweek onward, and could at times through the extended forecast bring about some chances for precipitation (although very light amounts) in the region. By late next week, highs may struggle to get much warmer than the low 60s.

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AVIATION

Southwest flow aloft through the TAF period as an upper-ridge progresses eastward. VFR all areas with BKN250 being observed so far this evening. For tonight into Sunday, mostly VFR all terminals aside from coastal areas. According to the HREF, KHQM has a 65-70% chance of ceilings below 1,000 ft 10z-16z Sunday and if manifest - should return back to VFR towards the afternoon. Northerly winds this afternoon 4-8 kt becoming light tonight. Weak front entering on Saturday will increase surface winds with gusts up to 20-25 kt in the afternoon.

KSEA...Confidence is leaning towards VFR throughout the TAF period. Probabilities of cigs below 3,000 ft for Sunday morning is around 10%. WNW surface winds 5-10 kt, shifting to the northeast around 5 kt or less late before veering towards the SW 14-16z Sunday between 5-10 kt.

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MARINE

High pressure will continue to build over the offshore waters this into next week. The main concern in this period is westerly winds through the Strait of Juan de Fuca where winds may reach SCA criteria. The next likelihood of this occuring is Sunday afternoon and evening. Otherwise, winds will remain light and primarily out of the north going into next week. A few ensembles hint a more organized system midweek next week. Seas 4-6 ft with a couple areas potentially seeing 7 ft seas next week at times.

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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...None.