textproduct: Seattle/Tacoma

SYNOPSIS

Weak system moving by to the north today. Upper level ridge building tonight into the weekend. Ridge shifting east Sunday night. Another weak system will move by to the north Monday night and Tuesday. Dry upper level trough over the area Wednesday and Thursday.

SHORT TERM /TODAY THROUGH SUNDAY/

The latest forecast remains on track with no updates. Weak shortwave moving by to the north today with a chance of showers along the north coast and over the interior from about Everett northward. For the remainder of the area cloudy skies to start with a little bit of sunshine in the afternoon. Highs in the mid to upper 50s.

Upper level ridge beginning to build over the area tonight with the ridge continuing to build through Saturday. Clearing skies will allow temperatures to drop Saturday morning into the 30s in many locations. Low level flow turning offshore Saturday marking the beginning of a brief warming trend. Highs in the lower to mid 60s.

Low level offshore flow with the upper level ridge over the area Saturday night into Sunday. The ridge axis slips off to the east turning the day Sunday turning the flow aloft southwesterly. This will push some high clouds over the area. Lows in the lower to mid 40s. Highs in the 60s and lower 70s.

Felton

LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/

Monday looks to be the warmest day in this short warm spell for the interior even with the upper level ridge axis well to the east. Low level flow turning onshore cooling highs on the coast down 5 to 10 degrees, into the mid 50s to lower 60s. Marine air not reaching the interior in time to cool things off. Highs again in the 60s and lower 70s.

Classic marine push scenario Monday night with an upper level shortwave moving by to the north increasing the low level onshore flow. Stratus along the coast moving inland in the early morning hours. Highs 10 degrees or so cooler Tuesday for the interior, in the mid to upper 50s. Highs on the coast in the lower to mid 50s.

Dry upper level trough moving down out of the north settling over the area Wednesday and Thursday. Low level onshore flow weakening Tuesday night. This combined with the dry northerly flow aloft making a couple of sunny days in the middle of next week. Highs near normal, mid 50s to lower 60s.

Lows in the lower to mid 40s Monday and Tuesday morning cooling into the 30s with less cloud cover Wednesday and Thursday morning. Frost advisories may once again be needed for the Southwest Interior.

AVIATION

West/northwesterly flow will persist aloft through the day as weak upper level ridging builds into the area. Conditions across the area terminals remain mostly VFR with mid and high level clouds filtering in overhead. A weak frontal system will clip the northern portion of the area today and may bring some additional light shower activity for areas along the North Coast and across the North Interior. Ceilings, especially for terminals from KPAE northward, may drop to MVFR this morning for a few hours, before lifting and improving towards FEW/SCT from south to north through the afternoon. Southerly surface winds persisting at 5-10 kt will transition to light northerly by this evening, likely between 00-06Z Sat.

KSEA...VFR conditions this morning with mid and high cloud cover streaming in overhead. The probability of MVFR cigs developing at the terminal this morning peaks between 11-18Z at around 20 percent. Clouds will scatter and become FEW/SCT by late Friday afternoon- evening. Southerly surface winds persisting between 5-10 kt today will become light around 5 kt or less and shift to the north between 02-05Z Sat.

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MARINE

High pressure will continue build over the area waters today as a weak frontal system passes to the north and clips the northern coastal waters. Overall, do not expect much in the way of impacts for the area waters with this system. Seas currently hovering between 7-9 ft will continue to subside towards 4-7 ft through the morning and will stay within this range through the weekend. High pressure will remain situated over the area waters over the weekend, while a thermally induced trough over Oregon builds northward along the coast. This will allow for flow to turn northerly or weakly offshore at times on Saturday and Sunday.

Flow will then switch back to onshore early next week as the next frontal system passes to the north. A strong westerly push is possible along the central and eastern Strait of Juan de Fuca Monday night into Tuesday. Seas across the coastal waters will build towards 7-10 ft Tuesday into Wednesday. Flow will then return to northerly or become weakly offshore at times Wednesday and Thursday as lower pressure remains situated over the area and high pressure remains situated over the northeast Pacific.

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HYDROLOGY

No river flooding the next 7 days.

SEW WATCHES/WARNINGS/ADVISORIES

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