textproduct: Seattle/Tacoma

SYNOPSIS

The pattern will continue to remain dry with upper level ridging over western Washington Wednesday into early Thursday. Thursday morning may see a few areas of fog or low stratus in the Southwest Interior. Active weather will return finishing the week into next week, with chances of precipitation, and temperatures dropping a few degrees.

SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/

Western Washington sits under a transient ridge this afternoon that will continue to shift southward tonight into Thursday. The weather will continue to remain dry this afternoon with just a few low clouds close to the waters and high cirrus. Temperatures this afternoon have reached the upper 40s/low 50s, and will drop tonight into mid 30s, with winds becoming calm. Patchy to areas of dense fog are likely to redevelop tonight/Thursday (especially in the Southwest Interior with cooler temperatures/dew point spreads).

The ridge will give way to a trough on Thursday, with a cold front in trail at the surface. While fog/low clouds will be present Thursday morning, there still will likely be a brief clearing of the clouds early afternoon before the clouds fill in late in the day. Temperatures may be a couple degrees cooler (compared to Wednesday) but still around 50 for most. The precipitation chances will increase Thursday night/Friday for the whole region. The Cascades, and the Olympics/Pacific Coast have the highest chance of seeing precipitation (which is expected to come through as bands or showers). Given the limited moisture ahead of the front, the QPF amounts are light in nature, with the lowlands only seeing a tenth-two tenths of an inch of rain through Saturday, and the mountains seeing half an inch to an inch of QPF. Snow levels will be around 3,000 ft will keep snow impacts limited to higher peaks (with only a 10% chance of more than 6 inches of snow at Snoqualmie/Stevens Passes). Additionally, while seas are expected to remain below high-surf threshold (20 feet plus), waves of 16 to 18 feet are possible Friday along the Pacific Coast, and beachgoers should be aware of the unsettled seas.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

The previous mentioned front will pass through on Saturday, with only a 30% chance of precip remaining Saturday/Sunday in the Cascades/South Interior. Snow levels behind the front will drop to around 1,000-1,500 feet Sunday into next week. High temperatures look to remain in the mid 40s through next week, with lows dropping into the low 30s (with Monday morning being the coldest). A couple surface troughs behind the front will keep a slight chance /chance of precipitation, although once again moisture is very limited with only minor lowland/mountain accumulations expected. If a shower is heavy enough in the lowlands early next week, it may be possible to see a couple of snowflakes make their way to the ground. The ensembles are favoring the active weather pattern to continue next week, with potential for a stronger system producing some significant mountain snow midweek next week. Please stay tuned for updates on this potential system.

HPR

AVIATION

Dry and stable conditions through Thursday with weak high pressure over the region. The flow aloft is light/variable, becoming westerly On Thursday. Low level fog/stratus expected once again during the overnight hours - mostly over the interior and coast. Interior low clouds should dissipate by 19-21Z. Rain from a weak frontal system will reach the coast after 00Z Friday. 33

KSEA...VFR conditions this afternoon and evening with N winds around 5 kt. Winds becoming S/SE by 09-12Z with IFR-MVFR stratus forming. 33

MARINE

High pressure with generally light winds over the waters through Thursday. Seas will build over 10 ft Thursday afternoon and a Small Craft Advisory is in effect for the Coastal Waters. A weak front will move inland on Friday with seas remaining elevated. Brief, light, offshore flow will develop over the weekend. Additional frontal systems will clip western WA over the week ahead. 33

HYDROLOGY

No river flooding is expected over the next 7 days.

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Small Craft Advisory from 10 AM Thursday to 4 PM PST Friday for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From Cape Flattery To James Island Out 10 Nm-Coastal Waters From James Island To Point Grenville 10 To 60 Nm-Coastal Waters From James Island To Point Grenville Out 10 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm.