textproduct: Seattle/Tacoma

SYNOPSIS

Conditions are favored to trend drier over the weekend with near-seasonal temperatures. High pressure then builds over the area next week, bringing continued dry weather and well-above average temperatures along with Moderate HeatRisk.

SHORT TERM /TODAY THROUGH SUNDAY/

Latest satellite imagery shows an abundance of low level clouds over W WA this morning thanks to plenty of moisture from Thursday's rains. The upper level low responsible for such is easily seen just off the NWern WA coast, although its movement to the northeast is not quite what models had been advertising. Regardless, new development of thunderstorms over E WA this early morning shows that at least for now, W WA seems to no longer be under any direct influence from this system.

Low chances for lingering showers remain possible this morning and afternoon over the northernmost portions of the Olympic Peninsula, otherwise, dry conditions expected to resume today. Following the trend established 24 hours ago, models seem to be slowing down the ramping up of temperatures in favor of a slower warming trend...which makes sense given that the upper level trough associated with the aforementioned low will linger for at least the first half of the weekend. As such, highs today will only see a few degrees of warming...into the lower to mid 70s for the interior and mid 60s along the coast. Saturday continues this incremental increase with highs generally in the mid 70s /still mid 60s for the coast/ and Sunday warms up to the mid 70s to near 80 as the coast finally starts to see some movement upward, generally in the mid to upper 60s. As such, this will keep HeatRisk down in Minor/Yellow throughout the short term period.

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LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/

Upper level ridging over the eastern Pacific starts to move into W WA Sunday evening, and by the time this feature gets its axis along the coast Monday, it will fuel a steep warm-up to temperatures as much as 10 degrees above climatology for this time of year. Highs Monday ranging generally in the mid 80s to near 90 while the coast sees temps in the lower to mid 70s. Ridging over the Four Corners region ends up getting drawn northward for the first half of next week, keeping conditions hot and dry. Highs Tuesday look to be the warmest of the period with inland temperatures in the upper 80s to lower 90s. Temps cool very slightly, a degree or two at best, with daytime highs both Wednesday and Thursday ranging in the mid to upper 80s. All that said, it should not come as any surprise that this will also push HeatRisk higher with widespread Moderate/Orange conditions for the interior lowlands each day of the long term period. Tuesday and Wednesday are also showing isolated patches of High/Red...which will need to be monitored should temps trend any higher for possible heat related headlines.

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AVIATION

An upper level low centered just west of Cape Flattery early this morning will gradually lift northward into British Columbia today with southerly flow aloft becoming southwesterly tonight. The low level flow is light onshore. Widespread low level moisture west of the Cascade crest will produce mostly MVFR ceilings through around 18Z before gradually lifting and scattering for most areas this afternoon. Ceilings may linger into mid-afternoon along the coast. Low MVFR or IFR ceilings are expected to redevelop along the coast tonight. Confidence in areal coverage of low ceilings for interior areas Saturday morning, especially east of Puget Sound, is low at this time.

KSEA...MVFR ceilings are expected to persist through around 18Z before lifting and scattering out this afternoon. There's around a 50% chance or so of MVFR ceilings for a period between 11Z and 17Z on Saturday. Surface winds southerly 6 knots or less will veer to the west/northwest by around 00Z then light north/northwesterly late this evening.

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MARINE

Weak surface low pressure over the coastal waters today will dissipate on Saturday as a broad surface ridge centered well offshore expands eastward. This will lead to varying degrees of onshore flow into the middle portion of the coming week. Thermally induced surface low pressure is expected to expand across the interior of Western Washington Monday through Wednesday. As a result, diurnally driven westerly pushes in the strait can be expected as well as occasionally gusty northwesterlies over the outer coastal waters with both areas reaching small craft advisory strength at times.

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FIRE WEATHER

Fire weather concerns will linger throughout the forecast period as a hotter and drier pattern returns quickly over Western Washington, especially into early next week. This has the potential for increasing fire activity from any new lightning starts from Thursday's convection.

SEW WATCHES/WARNINGS/ADVISORIES

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