textproduct: Seattle/Tacoma

SYNOPSIS

Weak upper level trough over the area today and tonight will move east Sunday. Weak upper level ridge Sunday and Monday will move east Tuesday. Another upper level trough will move over Western Washington Wednesday and remain through the end of the week.

SHORT TERM /TODAY THROUGH MONDAY/

Satellite imagery shows clouds filling in pretty fast over western Washington early this morning. The aurora was visible on some web cams north of Seattle before the clouds arrived. Temperatures at 3 am/10z were in the 50s and lower 60s.

Weak upper level trough over Western Washington today with light onshore flow in the lower levels. Pretty much a replay of Friday with morning clouds giving way to some sunshine in the afternoon. Highs in the upper 60s to mid 70s over the interior and mid 60s along the coast.

Upper level trough hanging over the area tonight before moving east Sunday. Low level flow turning light overnight with northerly flow in the lower levels Sunday. This will thin out the marine layer leading to an earlier breakout on Sunday. Breezy north wind in the afternoon especially near the water. With a little more sunshine highs a touch warmer, in the 70s over the interior and upper 60s along the coast.

Temporary upper level ridge building Sunday night and Monday. %00 mb heights rising into the upper 570 dms to lower 580 dms. light flow in the lower levels. Monday will be the warmest day in the next seven days for the interior with highs in the mid 70s to mid 80s. Highs on the coast with an afternoon seabreeze staying in the mid to upper 60s. Felton

LONG TERM /MONDAY NIGHT THROUGH FRIDAY/

Upper level ridge moves east Monday night with an upper level trough and associated front approaching the coast Tuesday. Increasing onshore flow during the day Tuesday will drop highs in the interior back into the 70s. Highs on the coast in the lower to mid 60s.

Upper level trough and associated front moving through Wednesday for mostly cloudy skies and a chance of rain for most of the area. Highs continue to cool with 60s and lower 70s in the forecast.

Weak upper level trough hanging around Wednesday night through the end of the week. Low level onshore flow making for a morning clouds afternoon sunshine scenario Thursday and Friday. Highs remaining near or a couple of degrees below normal, in the upper 60s to mid 70s over the interior and mid 60s on the coast.

AVIATION

MVFR cigs slowly filling in this morning, expecting widespread MVFR cigs in within the next hour or so. Improvement to VFR expected after 17-19z. The coast may see some brief improvement this afternoon to low-end VFR. However, it is possible that ceilings may hover around high-end MVFR. Another round of widespread low clouds expected tonight/early Sunday morning, with latest probabilities around 30-50% for interior terminals and 60-90% for the coast for MVFR cigs. Southwesterly winds in the interior terminals and northwesterly winds along the coast and Strait of Juan de Fuca this morning. Strong onshore flow this evening along the Strait of Juan de Fuca with gusts to 20 kt possible through Sunday morning. This will result in northwesterly winds spilling into Puget Sound terminals this afternoon, then shifting northeasterly in the evening with gusts to 15 kt possible.

KSEA...MVFR conditions early this morning. Ceilings expected to improve this afternoon after 18z. MVFR cigs look to return (40% chance) early Sunday morning after 11z. Southwesterly winds this morning 5-7 kt will shift northwesterly this afternoon after 21z to 7-9 kt. Northeasterly winds 8-12 kt after 02z with gusts to 15 kt through Sunday morning.

29

MARINE

A rather stagnant weather pattern will persist over Washington's waters into next week. Broad high pressure over the northeast Pacific and lower pressure inland will keep an onshore flow pattern. This will result in increased westerlies through the Strait of Juan de Fuca each evening, some having the potential to reach small craft thresholds. There is high confidence (greater than 70%) for strong westerlies this evening through the Strait. Guidance also suggests there is a 70% chance or higher for small craft winds to reach Admiralty Inlet this evening as well. Therefore, small craft advisories are set to go into effect the Central/East Strait and Admiralty Inlet later this evening. Winds will also increase for the lower coastal waters late this evening to advisory thresholds. There is high confidence (75-85%) for increased northwesterly winds Sunday evening across all portions of the coastal waters, likely requiring additional advisories. Long term guidance highlights a 60-90% chance for small craft winds through the Strait next week, likely requiring additional headlines. A few weak fronts will move through the waters throughout the week, but high pressure is expected to rebuild quickly over the waters behind the fronts.

Seas will build late this evening to 6-8 ft and up to 10 ft through Monday. Seas will gradually subside below 10 ft on Tuesday to 4-6 ft.

29

FIRE WEATHER

Even with the slight warming trend into next Monday the low level flow never turns offshore. This will keep good overnight relative humidity recoveries in the forecast and help subdue fire weather concerns despite the warmer temperatures. Another front in the middle of next 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. 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 from 3 PM this afternoon to 3 AM PDT Sunday for Central U.S. Waters Strait Of Juan De Fuca- East Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory from 5 PM this afternoon to 3 AM PDT Sunday for Admiralty Inlet.

Small Craft Advisory from 7 PM this evening to 9 AM PDT Sunday for Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm.