textproduct: Seattle/Tacoma

SYNOPSIS

High pressure remains over the region through Thursday. Morning fog and stratus will continue likely until Thursday morning, where it will become less widespread. Sunny afternoons are expected, with seasonably warm temperatures. A front crosses the region late Friday into Saturday, bringing another round of rain and cooler conditions.

SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/

This evening: a couple areas of fog/low stratus have remained in place in western Skagit County, and along the Pacific Coast. Expect coverage to increase overnight, with the best chance for fog being in the north interior (from Bellingham to Everett), and remaining areas seeing a mix of low stratus and mist. Slightly less extensive cloud cover will bring an earlier clearing and slightly warmer temperatures Thursday.

The system moving in on Friday will be weak, and the expected QPF is minimal around a few hundredths of an inch across the Cascades and northern portions of Puget Sound. While the precipitation won't last very long, the pattern change will usher in cooler temperatures, with highs on Friday knocked back down to the low 60s. Snow levels drop to around 5000 ft late Friday night, so the higher terrain particularly in the North Cascades may see a dusting of snow. Expect breezy winds along the coast, Strait of Juan de Fuca and waterfront areas of Puget Sound on Friday.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

Overnight lows will be decreasing over the weekend as the pattern becomes focused on low pressure over the NW. Saturday morning lows will be in the upper 30s across the Cascade passes, and low 40s in the foothills. The lows decrease a few degrees more come Sunday morning. Stay tuned to the forecast as it relates to frost and freeze potential for agricultural concerns and sensitive vegetation.

Cooler temperatures look to continue into early next week as low pressure churns in the Gulf of Alaska. Some of the models depict another chance at rain on Tuesday into Wednesday, but the ensembles are mixed on exact placement of the low and resultant weather systems.

AVIATION

A similar scenario is likely tonight/Thursday where the areas of fog/low stratus that are able to survive the burnoff will expand as north winds become calm or light/variable. The best chance for visibilities under a mile will be the north interior, Strait of Juan de Fuca, Pacific Coast, and south interior. Remaining areas still have a high chance of seeing LIFR ceilings, most of which will clear late Thursday morning/early afternoon. Winds will pick up out of the north for most Thursday at 5-10 kt.

KSEA...VFR conditions through the evening. Stratus to the north near KPAE and northward is likely to reform and fill south through Puget Sound late this evening/overnight. While the likelihood for low LIFR visibilities has decreased, there still remains a high likelihood of LIFR ceilings forming as early as 09Z, and persisting into 18Z before lifting. Winds this afternoon/Thursday afternoon are out of the north 5-10 kt, becoming 5 kt or less overnight.

HPR

MARINE

High pressure will remain situated over the coastal waters the next few days, while a thermal trough builds northward along the Washington coast. This will continue to promote northerly winds across the coastal waters into Thursday. Northerly winds may become gusty to 25 kt at times across the coastal waters off of Grays Harbor today and Thursday afternoon, but expect the stronger, more sustained winds to generally remain south of the area. Onshore flow will return by Thursday evening, with guidance indicating a 30-50% chance of westerly winds exceeding small craft strength along the central and eastern Strait of Juan de Fuca. A frontal system will then move into the area waters Friday into Saturday, bringing the likelihood (>80% chance) of small craft strength winds to the coastal waters and the Strait of Juan de Fuca. Seas will build in the system's wake, with latest GEFS probabilities indicating a 60-80% chance of seas exceeding 10 ft across the coastal waters by Friday night.

Winds will ease and seas will gradually subside through the day on Saturday as the system exits the area. High pressure will then build back into the coastal waters by Sunday, while a thermal trough expands northward along the coast again.

SEW WATCHES/WARNINGS/ADVISORIES

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