textproduct: Seattle/Tacoma

SYNOPSIS

Warm and dry conditions prevail across the area through Friday. Chances for rain return late Friday into Saturday with much cooler conditions beginning this weekend. Showers will gradually taper off Sunday with weak ridging on Monday. A stronger low pressure system looks to reach the area mid-week.

SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/

Weak upper level ridging will move across the area Thursday night into Friday over southern British Columbia with an upper level low moving inland across southern Oregon and northern California. Mostly clear skies continue today but high clouds will begin to fill in more tonight into Friday. This will help to moderate low temperatures tonight (into the upper 30s to mid 40s). Warm conditions continue Friday with highs in the 60s to low 70s.

Moisture will begin to move northward from Oregon into southwestern Washington allowing for chances for showers to begin late Friday, but the bulk of the precipitation is expected on Saturday. High temperatures will drop into the mid to upper 50s.

LONG TERM /SUNDAY THROUGH THURSDAY/

Unsettled conditions continue into Sunday as showers begin to taper off. Monday looks to remain mostly dry as weak, transient, upper level ridging moves across the area and the upper level low moves inland. Cooler and more active conditions then return mid-week as an upper level trough moves in from the northwest, which will bring in more windy and wet conditions. Lower snow levels will bring light to moderate snowfall to the mountains and passes. Below normal temperatures return with more frost conditions possible with cold morning lows.

62

AVIATION

Flow aloft has transitioned more south/southwesterly and will continue into Friday as an upper low slowly moves towards the California coast. Conditions remain VFR this afternoon and are expected to continue through the majority of the TAF period. Expect more mid to high level cloud cover to stream into the region Friday morning, before showers start to move in from the south later Friday afternoon into evening. Winds have been persisting from the north/northeast this afternoon at 5-10 kts, but will ease and become light at 6 kt or less after 06Z.

KSEA...VFR conditions expected through the majority of the TAF period. Northerly winds around 5-8 kts this afternoon will become light around 6 kt or less after 06Z.

14

MARINE

Northerly winds will continue over the area waters tonight through Friday with high pressure situated over the northeastern Pacific and a low moving inland into California. A low pressure system will move southward to the west of the area waters on Friday, but will not have a significant impact to the area.

High pressure will then rebuild over the northeastern Pacific over the weekend, while low pressure remains situated along the West Coast. Onshore flow will persist as a result, with periods of diurnal westerly pushes expected along the Strait of Juan de Fuca at times. High pressure will then build back into the area waters on Monday. At this time, the strongest westerly push down the central and eastern Strait of Juan de Fuca looks like it will be Monday night into Tuesday. A frontal system will then move through area waters late Tuesday into Wednesday. At this time, guidance continues to indicate roughly a 40-60% chance for winds approaching small craft criteria for the coastal waters and portions of the Strait of Juan de Fuca.

Seas will primarily range between 4-7 ft through the weekend and into early next week, before approaching 10 ft on Wednesday.

14

HYDROLOGY

No river flooding is expected in the next seven days.

SEW WATCHES/WARNINGS/ADVISORIES

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