textproduct: Seattle/Tacoma

SYNOPSIS

Showers and breezy winds will continue today as a warm front pushes northwrad. A high pressure ridge will build over the region through the remainder of the week, bringing in unseasonably warm and dry conditions with rounds of morning fog and low stratus. A pattern change is on tap for the weekend, with wet and cooler conditions returning.

SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/

As an upper level ridge builds northward over the western US, a warm front will continue to lift northward across western Washington today. Light shower activity and breezy winds will continue to taper off throughout the afternoon and drift northward as the frontal system lifts into British Columbia.

High pressure will continue to amplify over western Washington on Tuesday and Wednesday, allowing for drier and warmer conditions. However, morning fog and low stratus are likely to develop each morning and erode for most areas by the early afternoon. Cloudy skies will stick around on Tuesday, as a weak system tries to approach the coast. Areas along the northwest Olympic Peninsula and northern inland water coastlines may see a few sprinkles tomorrow, but measurable rain accumulations are not expected. Temperatures Tuesday will warm several degrees under the influence of the high pressure ridge, with most areas seeing highs in the mid to upper 50s. Much clearer conditions on Wednesday afternoon will allow for even warmer high temperatures in the upper 50s to lower 60s for most areas.

LONG TERM /THURSDAY THROUGH MONDAY/

Operational forecast models and ensembles are both in good agreement over the ridge dominating the forecast through the remainder of the work week. This will maintain dry and warm conditions across western Washington through at least Friday, with potential for morning fog and low stratus and mostly clear afternoons. Temperatures through Friday are on track to peak in the mid to upper 50s.

A pattern change is on tap by the end of the weekend, although some degree of uncertainty still remains over the timing. The ridge is favored to move eastward and out of the area by the end of the weekend as an upper level trough moves into the Pacific Northwest. This will bring in the next round of precipitation with snow levels lowering to near 4000 feet. After this system moves in, an active and unsettled pattern is favored to continue into next week.

15

AVIATION

The cold front has progressed to the east, with scattered showers pushing into the Cascades this afternoon. Isolated showers will continue this evening in portions of western Washington. Widespread MVFR to IFR cigs are leftover this afternoon, and will continue tonight. Expect light southerly flow to continue across the terminals into the overnight period, becoming variable overnight. High pressure is rebuilding, but will require more clearing for fog potential to develop (KOLM and a chance at PWT). A rebound to VFR cigs and light flow is expected after 21Z for most terminals tomorrow.

KSEA...MVFR at the terminal this afternoon, with southerly flow of 10-12 kts. Rain has largely moved to the east, though periods of mist may be present throughout the evening and into the overnight period. Cigs are expected to remain MVFR throughout the night, with stratus likely in the morning not to get much lower than around 020. A return to VFR under weak ENE flow (4-6 kts) is expected after 18Z.

21

MARINE

Seas are going to remain elevated between 9-12 feet through tonight before easing up, with the winds also decaying into the rest of the afternoon. A decaying system well offshore could bring the seas back up to 10-12 feet again late Tuesday night into Wednesday, which would be the next time period with SCA potential.

As high pressure builds in through the middle of the week, expect periods of marine fog over the next several days. Visibility restrictions in Puget Sound and the coastal waters are possible as fog and/or low stratus develops.

21

HYDROLOGY

A Flood Warning remains in effect for the Skokomish River in Mason County, as recent rainfall has caused the river to rise into minor flood stage. With little additional accumulation expected today, the river is forecast to crest later this evening and recede below flood stage Tuesday morning.

Additional river flooding is not expected over the next 7 days.

15

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Small Craft Advisory until 4 PM PST this afternoon for Grays Harbor Bar.

Small Craft Advisory until 1 AM PST Tuesday 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.