textproduct: Seattle/Tacoma

SYNOPSIS

A series of weather systems will continue to bring periods of precipitation and locally gusty winds through Friday. High pressure briefly rebuilds Saturday for a warmer and drier day before another system arrives Sunday. High pressure returns and strongly rebuilds over the region next week bringing a stretch of warmer and drier conditions.

SHORT TERM /TODAY THROUGH SATURDAY/

A low pressure system is located just off the Washington coast this morning and is bringing a round of rain to the area this morning. The heaviest rain is occuring along the Pacific coast and along the west/south slopes of the Olympics, while much of the interior will be mostly shadowed. Breezy winds are also being observed with this system, primarily along the coast and northern interior with gusts 25-35 mph being observed. These conditions will continue though the late morning until the cold front traverses the area late morning. Scattered showers may continue, mainly over the mountain, through the remainder of the day. There will not be much of a break as the warm front from the next system begins to move onshore tonight, bringing renewed chances for rain and locally breezy conditions across the area on Friday. With the heaviest precipitation focused on the Olympics, that will be the primary focus for potential hydrologic impacts. With snow levels 5000-6000 ft, rain will also be observed through the mountain passes. Temperatures will remain mostly steady, with highs in the low 50s and lows in the mid 40s.

On Saturday, a building upper level ridge will briefly build across the area, allowing conditions to dry out and warm up for most. A few light showers may be able to persist over the higher elevations and the north coast. Highs will rise into the mid 50s to near 60. Lows a bit cooler, in the lower 40s.

Large waves will continue to build up to around 16-18 ft along the coast early this morning, developing high surf conditions. Waves should begin to subside tonight.

62

LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/

Another upper level trough will send a surface frontal system across the area on Sunday, returning to wet and cooler conditions with highs back into the low 50s. An upper level ridge will move in and begin to build on Monday, but another warm front may just skirt the region, keeping chances for rain in the forecast, in particular for the northwestern portions of the area. Models continue to be in good agreement that the aforementioned ridge will continue to develop and amplify into an omega blocking pattern from Tuesday going into the middle of next week, allowing conditions to dry out and warm up once again, back into the upper 50s to near 60.

The threat for coastal flooding will also return this weekend into early next week. At this time, the weather does not look to significantly exacerbate impacts, with only minor impacts currently expected primarily for sensitive areas in the Puget Sound and Salish Sea. The coastal flooding threat will continue to be evaluated and refined throughout the week.

62

AVIATION

West to southwest flow aloft will continue across western Washington through the TAF period with broad troughing over the northeastern Pacific and upper ridging inland. Widespread rain continues to move in across western Washington early this morning ahead of an approaching frontal system. Rain will taper to showers by mid to late morning in its wake, but another round of more widespread rain will move into the region later this afternoon into this evening as the next warm front brushes the area. Conditions at the area terminals are primarily VFR to MVFR this morning, though can't rule out conditions briefly dropping to IFR in heavier rain. Conditions will generally rebound back to VFR by mid morning, but look to drop back down to MVFR by this evening with the next round of rain. Gusty southeast surface winds are expected for the coastal areas and the northern interior terminals this morning as the front moves through and again late tonight into early Friday.

KSEA...VFR conditions continue this morning with light rain at the terminal. Conditions may briefly drop to MVFR in any heavier rain passing through this morning. Surface winds S/SE at 10-15 kt with occasional gusts to around 20 kt expected through the morning. Winds will ease back towards 5-10 kt by 18Z. Another round of more widespread rain will move into the terminal this evening, with a 40 percent chance of ceilings lowering down to MVFR between 23-02Z.

14

MARINE

A warm front brushing the region will be followed by a cold front moving across the area waters today. Winds across the waters will be gusty as result, with southerly gales expected for the coastal waters and the East Entrance of the Strait of Juan de Fuca through the morning hours. Winds will ease in its wake, but will remain breezy across the coastal waters and northern interior waters through much of the day with small craft southerlies expected. Coastal seas will continue to build towards 16-18 ft through the morning hours.

Another warm front will move into the area waters tonight and will be followed by a trailing cold front on Friday. This system will bring yet another round of southerly gales to the coastal waters and the eastern Strait and small craft strength southerlies to the northern interior waters into Friday morning. Coastal seas will remain elevated between 12-16 ft.

The pattern will remain active into early next week, with another, weaker system expected to move across the area waters over the weekend. Seas will subside heading into the weekend and will generally range between 9-12 ft heading into early next week.

14

HYDROLOGY

A series of systems moving across the region will bring multiple rounds of rain to western Washington through Friday, with the highest amounts remaining aimed at the Olympic Peninsula. Conditions are still on track to see an additional 1-3 inches of rain for the south facing slopes of the Olympics, with localized 4+ inches still possible in spots. This, along with rising snow levels, will likely lead to flooding on the Skokomish River by late morning today. Additional rainfall over the weekend could keep the Skokomish river in or close to flood stage over the weekend. Other rivers draining from the Olympics will continue to be closely monitored with each round of rain, but river flooding is not expected elsewhere.

14

SEW WATCHES/WARNINGS/ADVISORIES

WA...Flood Watch through late Friday night for Foothills of the Western and Southern Olympic Peninsula-Middle Chehalis River Valley-Olympia and Southern Puget Sound-Olympics- Southern Hood Canal-Willapa and Black Hills.

High Surf Advisory until 10 AM PST this morning for Grays Harbor County Coast-Northern Washington Coast.

PZ...Small Craft Advisory until 10 PM PST this evening for Grays Harbor Bar-West Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory until 8 AM PST this morning for Central U.S. Waters Strait Of Juan De Fuca.

Gale Warning until noon PST today for East Entrance U.S. Waters Strait Of Juan De Fuca.

Gale Warning from 7 PM this evening to 10 AM PST Friday for East Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory from noon today to 7 PM PST this evening for East Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory until 4 AM PST Friday for Admiralty Inlet- Northern Inland Waters Including The San Juan Islands.

Small Craft Advisory until 10 AM PST this morning for Puget Sound and Hood Canal.

Gale Warning until 10 AM PST this morning 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.

Gale Warning from 4 PM this afternoon to 10 AM 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.

Small Craft Advisory from 10 AM this morning to 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.