textproduct: Seattle/Tacoma

SYNOPSIS

The weather pattern remains fairly steady with high pressure situated offshore through the week with morning clouds and afternoon sun. Temperatures will rise a bit each day through the end of the week before beginning to cool off this weekend into early next week.

SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/

North/northwesterly flow prevails across western Washington through the next several days, and with surface high pressure dominating offshore, the pattern remains pretty steady. Plenty of sunshine for most this afternoon with some mountain cumulus and a dissipating front approaching the coast. High temperatures this afternoon on track to reach the mid to upper 60s. This front will, however, be enough to bring a stronger onshore push tonight which will bring more widespread low stratus and some drizzly conditions across the area for Tuesday morning. Lows in the low to mid 40s. Clouds should slowly lift through the day but expect most of the day to be cloudy. Highs a little cooler, in the low to mid 60s.

The upper level ridge offshore will begin to amplify and tilt onshore towards WA and BC, which will allow for a warming and sunnier trend to begin. With clouds expected to clear out early Wednesday morning, expect temperatures to be warmer, with highs reaching the upper 60s to low 70s.

LONG TERM /THURSDAY THROUGH MONDAY/

The warming trend will continue through the end of the week, with the warmest temperatures across the region expected Thursday and Friday as the ridge traverses the area and more robust onshore flow begins to move in Friday into the weekend. Temperatures will top out Thursday and Friday into the low to mid 70s, with upper 70s to near 80 possible in the southwest interior and Cascade valleys.

The ridge deamplifies as it moves eastward and shortwaves begin to move through it. This should help to not just start to cool temperatures, but also bring in clouds and chances for showers. Currently the best chances for showers will be Sunday night into Monday, but there is still considerable uncertainty given the trough's evolution/placement, or if the ridge will win out and push the trough elsewhere.

62

AVIATION

North to northwesterly flow aloft as upper level ridging remains over the region with onshore flow in the low levels continuing. Puget Sound terminals /PWT, SEA, BFI/ generally seeing light and variable winds while remaining terminals seeing speeds ranging 8-12 kts this evening. These terminals should see speeds decrease late this evening to the 4-8 kts range.

Widespread VFR conditions over the majority of W WA this evening although starting to see marine stratus take root over the coastline where MVFR conditions have set up. The combination of the aforementioned onshore flow with an embedded shortwave aloft will allow for the low clouds along the coast to push inland. This will give rise to widespread MVFR conditions over the area Tuesday morning. Upper level ridging aloft will allow for cigs to improve back into VFR conditions with skies clearing by late Tuesday afternoon/early Tuesday evening.

KSEA...VFR conditions this evening with variable winds generally at or less than 5 kts. Speeds will increase slightly tonight, generally remaining around to 5 to 10 knots and turning S/SW after 06Z tonight. Cigs to lower overnight,reaching MVFR (50 to 60% chance) by 18Z late Tuesday morning. Conditions will rebound to VFR later Tuesday afternoon.

18/Mazurkiewicz

MARINE

Surface high pressure will remain over the northeastern Pacific throughout much of the week, bringing north to northwesterly winds over the coastal waters. A splitting weak system will cross over the waters tonight into Tuesday, bringing an increased period of onshore flow throughout the Strait of Juan De Fuca. A small craft advisory is in effect through Tuesday morning for increased westerlies.

High pressure will rebuild midweek and continue throughout the rest of the week, which will provide continuous periods of onshore flow. Can expect in daily pushes down the Strait of Juan De Fuca through the rest of the week, which would likely generate small craft advisory winds. A weak system looks to enter the area waters Thursday into Friday.

Coastal seas generally increasing to 6 to 8 feet through the first half of this week, with seas increasing more to 8 to 10 feet late Thursday and into Friday.

Mazurkiewicz

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...Small Craft Advisory until 5 AM PDT Tuesday for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca.