textproduct: Seattle/Tacoma

SYNOPSIS

A frontal system draped over Western Washington today will bring rain and locally breezy winds through Friday night. Unsettled weather continues over the weekend with increasing southwest flow aloft Sunday. Another frontal system likely early next week.

UPDATE

Steady light to moderate rain continues to fall across much of western WA this morning. Rates remain below 0.20-0.25 inches an hour with this activity (highest rates will be up in the Cascades through the day today). Other than nuisance ponding on roadways and in low-lying areas, impacts remain pretty minimal (due to the lower rain rates). Updates were made to the aviation, marine, and hydrology sections of the AFD this morning.

HPR

SHORT TERM /TODAY THROUGH SUNDAY/

Areas of light rain and drizzle continue across Western Washington early this morning with a warm front draped over the area. Steadier rainfall is expected to increase this morning, particularly over the Olympia Peninsula and King County northwards. The warm front will slowly lift northwards into late Friday. Southerly winds will also increase in the warm sector today, mainly from Snohomish County southwards. Both HREF/REFS maintain probabilities of 50-80% for wind gusts over 30 MPH this afternoon into tonight from Everett area southwards. Probabilities drop towards less than 10% for gusts of 40 MPH for most areas, although both HREF/REFS do highlight the Everett (PAE) area for probabilities near 50%. All in all, increased winds are expected for those areas through tonight as well. Snow levels will also range between 5500 to 6500 feet today, resulting in high elevation snow in the Cascades, especially King County northwards in the location of heaviest QPF. Highs will be in the mid 50s for most areas, with upper 40s to low 50s near the BC border.

Steadier rainfall begins to taper off on Saturday, although lingering showers may continue at times. A brief period of drier weather will be possible for some Saturday night before there is another uptick in precipitation potential Sunday, especially along the Olympic Peninsula, with increasing southwest flow aloft. Highs Saturday and Sunday will be a few degrees warmer into the mid to upper 50s.

LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/

A weak frontal system will move towards Western Washington late Sunday, and bring unsettled weather into Monday for additional showers. The bulk of the energy will move southwards along the West Coast early next week, resulting in a weaker system offshore of Washington. Some uncertainty exists in regards to how long the unsettled weather lasts into Tuesday. At this time, have kept with NBM probabilities for precipitation ranging 20 to 40%. Another trough looks to move towards the West Coast on Thursday, but once again continued uncertainty exists in ensembles in the depth and location of the trough by late next week. Temperatures do look to cool to near to slightly below normal next week. JD

AVIATION

West northwesterly flow aloft with frontal system stalled over the area today. Front slowly moving out of the area tonight.

MVFR ceilings with local IFR/LIFR ceilings and visibilities in heavier rain through 00z. The exception to this is north of the front near KBLI where ceilings will be VFR into the afternoon hours. IFR/LIFR conditions improving later this afternoon into this evening as the heavier rain comes to an end but MVFR ceilings continuing over most of the area into Saturday morning.

KSEA...MVFR ceilings into Saturday morning. Could see a return yo IFR ceilings at times 18z/21z. Visibility 1-3sm in moderate rain until 21z.Visibility improving after 21z. Felton

MARINE

A small craft advisory remains in effect for the coastal waters for elevated seas around 10 feet into the afternoon hours. The SCA will be allowed to expire late this afternoon. A front draped across area waters will increase southerly winds this afternoon and evening before decreasing overnight. Probabilities of wind gusts exceeding 25 kt range anywhere between 60-80% across Puget Sound with the threat only remaining there. Weaker systems will approach the area waters throughout the weekend.

Seas around 10 feet subsiding to 6 to 8 feet late this afternoon. Seas remaining in the 6 to 8 foot range over the weekend. Felton

HYDROLOGY

A series of progressive systems will bring rain to western Washington through the weekend. The heaviest rainfall is expected through Saturday, with 1/2 to 3/4 inch over much of the lowlands. Amounts over the Olympic Peninsula look to be a little less now as the heaviest rain band is staying and is forecast to stay just to the south - with about 1-2 inches expected in that period. For the Cascades of northern King County through Skagit County, expect rainfall amounts to range between 2-3 inches for the same period. Rivers are expected to rise over the next few days in these areas. At this time, river flooding looks less likely but remains possible on the Skokomish River in Mason County. Other rivers will also need to be monitored flowing off the Cascades of King, Snohomish, and Skagit Counties but flooding is not expected. JBB/JD

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Small Craft Advisory from 4 PM this afternoon to 4 AM PST Saturday for Puget Sound and Hood Canal.

Small Craft Advisory until 4 PM PST this afternoon 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.