An approaching front will bring rain to the coast this afternoon and inland this evening. Snow in the mountains will become heavy at times this evening into early tuesday. A convergence zone is likely to form tuesday with showers decreasing late. Drier weather will begin wednesday, with gradual warming through sunday. highs could reach 60 in spots over the weekend.
Radar shows precipitation just off cape flattery this morning as a frontal system approaches from the northwest. Models are in good agreement that rain will begin on the coast and over the north interior this afternoon, and spread southeast into the rest of western washington this evening. the front will move into the cascades 09z-12z. Southerly pressure gradients will increase this afternoon with breezy winds developing.
Steady rain and mountain snow overnight will taper to showers by tuesday morning. Moderately strong westerly flow aloft will support orographically enhanced snowfall along the west slopes of the cascades and passes. Snow will be heaviest tonight just ahead of the front but the passes will get some additional snowfall tuesday as colder air aloft and a puget sound convergence zone adds to the precipitation amounts. Total liquid qpf through tuesday should run about a half inch to an inch in the lowlands, and over an inch in the mountains. Snow amounts could approach a foot by late tuesday afternoon.
A puget sound convergence zone forming north of seattle should drift south into the seattle to tacoma corridor in the afternoon. Locally heavy rain with convergence zone bands is possible. Snow could become briefly heavy in both stevens and snoqualmie passes if a convergence zone stalls and extends eastward into the cascades. A winter weather advisory remains in effect in the cascades for snowfall totals of 8 to 15 inches.
A ridge of high pressure aloft will build rapidly off the coast wednesday. Residual showers over the mountains should end in the afternoon, and there will be some sun wednesday. This will be the start of a stretch of dry weather and gradual warming. Burke/mercer
Previous discussion...high pressure dominates the long range pattern keeping frontal systems mainly directed at southern british columbia. While mostly dry weather is expect for most locations wednesday afternoon through the upcoming weekend, clouds or even some sprinkles or very light spotty rain is not out of the question around the friday-saturday timeframe. The ecmwf is dry through the period but the gfs brings some very light qpf to the area, mainly the olympic peninsula and far north. Temperatures will gradually warm through the period, with highs potentially reaching close to 60 degrees by saturday and sunday. Lows will also moderate and remain mostly above freezing by the end of the week. Mercer
Flooding is not expected for the next 7 days.
Wa...winter weather advisory from 5 pm this afternoon to noon pdt tuesday for cascades of pierce and lewis counties-cascades of snohomish and king counties-cascades of whatcom and skagit counties.
Pz...small craft advisory until 6 am pdt wednesday for 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 for rough bar until 6 am pdt wednesday for grays harbor bar.
gale warning until 9 pm pdt this evening for coastal waters from cape flattery to james island 10 to 60 nm-coastal waters from cape flattery to james island out 10 nm.
small craft advisory until 5 am pdt wednesday for admiralty inlet-east entrance u.s. Waters strait of juan de fuca.
gale warning from 3 pm this afternoon to 2 am pdt tuesday for northern inland waters including the san juan islands.
small craft advisory until midnight pdt tonight for west entrance u.s. Waters strait of juan de fuca.
small craft advisory from 5 am tuesday to 5 am pdt wednesday for central u.s. Waters strait of juan de fuca.
small craft advisory until 5 am pdt tuesday for puget sound and hood canal.
A low pressure system is approaching the area this morning. Associated cold front will move through the coastal waters by early this evening and through the inland waters overnight. A gale warning remains in effect for the coastal waters from james island northward and for the northern inland waters. Small craft advisories are in effect for the remainder of the waters.
Behind the front, strong northwesterly winds will produce small craft advisory conditions across most of the waters into tuesday or tuesday night. Steep waves will also develop over the coastal waters in the strong northwesterly flow.
High pressure will build into the waters on wednesday with lighter winds. A weak front may brush the waters late thursday. Albrecht/ceo
A ridge of high pressure over western washington will gradually shift eastward today as a strong frontal system approaches the coast this afternoon and works its way into the interior during the evening hours. Northwesterly flow aloft will become westerly, while surface winds will shift to the south and increase ahead of the cold front. Increasing upper level moisture giving way to a broken high level cloud deck over the region this morning. Moisture will continue to increase and deepen as the frontal system approaches, allowing for vfr ceilings to gradually lower throughout the day with mvfr conditions likely this evening into tuesday.
Ksea...vfr conditions will continue through this afternoon, with ceilings lowering to mvfr during the evening hours ahead of the frontal boundary. Southerly winds at 5 to 12 knots. A few gusts to 20 kts not out of the question late tonight into tuesday. Rain looks to approach the terminal during the early evening hours. 14/ceo