textproduct: Seattle/Tacoma

SYNOPSIS

A weak ridge of high pressure will bring warmer and drier conditions to Western Washington into Tuesday. A weak frontal system will arrive on Wednesday with cooler temperatures and a little rain for parts of the area. Onshore flow will keep temperatures near normal for the second half of the week with areas of night and morning clouds.

SHORT TERM /TODAY THROUGH TUESDAY/

A weak upper level ridge will begin to build into the region today. Light onshore flow continues near the surface. After areas of morning clouds, the afternoon will feature mostly sunny skies with temperatures bouncing back to near seasonal averages for the first time in more than a week. A weak upper ridge axis will shift inland early Monday. With modest height rises and continued light onshore flow, this will allow interior temperatures to rise a few more degrees with areas from Seattle metro southward crossing the 80 degree threshold. The warming trend will be short with onshore flow ramping up Monday night ahead of a weak front approaching offshore. Tuesday will likely remain cloudy along the coast, but interior areas should see some afternoon sun along with several degrees of cooling.

LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/

A weak frontal system will drag onshore Tuesday night into Wednesday. The bulk of the light rainfall with this system will likely fall on the Olympic Peninsula and interior areas from around Everett northward. We may get a weak convergence zone Wednesday afternoon as well.

Looking further ahead into the second half of the week, the best description I can come up with is...seasonal. Western Washington will remain sandwiched between strong upper ridging over the Desert Southwest and anomalous upper troughing over British Columbia. This essentially keeps us in a persistent onshore flow pattern with 500 millibar heights that never really get much above the mid to upper 570s decameters. So, with that said, one would typically expect varying amounts of night and morning clouds, afternoon sun, and temperatures hovering within 2 to 4 degrees of normal for early July.

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AVIATION

Majority of ceilings VFR early this morning. Guidance still suggesting the possibility of MVFR cigs returning Sunday morning. Currently, highest confidence is with coastal terminals, where probabilities are between 50-60% after 10z. As for other terminals, there is a 20-30% chance of MVFR cigs after 12z. Shall MVFR cigs develop, widespread VFR conditions expected in the afternoon after 16z-18z. Increasing chances for MVFR cigs return Monday morning, with highest confidence (60-80% chance) along the coast, with a 50% chance of IFR cigs. Interior terminals have a 20-40% chance of MVFR cigs. Generally light NE to variable winds early this morning, turning WNW in the afternoon to 5-12 kt. Winds may get somewhat breezy Sunday evening along Puget Sound, with a few gusts to 15 kt possible.

KSEA...VFR cigs early this morning. Latest guidance suggests there is a slight chance (30%) for MVFR cigs between 12z-16z. Otherwise, VFR conditions in the afternoon/evening. Slight chance (20%) for MVFR cigs Monday morning. NE winds have remained slightly elevated this morning around 10-13 kt. Winds will shift NNW in the afternoon after 19z around 8-10 kt. NE winds in the evening 8-10 kt, decreasing to 5 kt or less after 09z. May see a few gusts to 15 kt Sunday evening between 02-06z.

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MARINE

A rather stagnant weather pattern will continue for Washiington's waters through the forecast period. Broad high pressure over the northeast Pacific and lower pressure inland will maintain a pattern of onshore flow. This will result in increased westerly winds through the Strait of Juan de Fuca each evening, some having the potential to reach advisory criteria. Sunday's westerlies are expected to remain advisory thresholds, as current probabilities rest at 20% or less. Starting Monday, guidance has moderate to high chances (50-95%) for winds through the Strait of Juan de Fuca reaching small craft advisory thresholds, possibly warranting additional headlines throughout the week. Moreover, a combination of winds and seas will small craft advisory conditions to the coastal waters this evening. A weak front will move over the waters Tuesday evening/Wednesday morning. This will slightly weaken high pressure over the waters, but it is expected to quickly rebuild behind the front.

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FIRE WEATHER

Low-level onshore flow will continue through the week. This will keep good overnight relative humidity recoveries in the forecast and help subdue fire weather concerns despite somewhat warmer temperatures. Another front in the middle of the week will bring a chance of rain to the area keeping fire weather concerns at a minimum.

We already have small fires cropping up in the Olympics and Cascades even without elevated fire weather conditions. If you are in the mountains the next few days please be extra careful.

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Small Craft Advisory until 3 AM PDT early this morning for Admiralty Inlet-Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory until 11 PM PDT this evening for Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm.