Dry conditions and clear skies are expected to continue tonight as high pressure aloft remains over western washington. Clouds will increase and rain will spread inland on monday as a front approaches the region. The rain will reach the interior lowlands late in the afternoon or on monday evening. afternoon highs will generally be around 50 on monday. Rain and mountain snow along with breezy to windy conditions is expected monday night. Showers and winds will slowly decrease on tuesday. Drier weather will return by late wednesday into next weekend with temperatures near or slightly above average.
High pressure over the waters will weaken and shift east tonight as a vigorous frontal system well offshore approaches the area. The front will move through the coastal waters late monday afternoon and through the inland waters monday night.
The winds with the incoming front will rapidly increase over the coastal waters monday morning. South winds will also increase over the inland waters monday afternoon as flow aloft interacts with the terrain and will continue into monday evening as the front moves inland. The gale watches were upgraded to warnings for the coastal waters from james island northward and for the northern inland waters. The small craft advisories were issued for the remaining 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 northwesterly flow.
High pressure will build into the waters on wednesday. A weak front may brush the waters late thursday. Albrecht
Wa...winter weather advisory from 5 pm monday 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 from 6 am monday to 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 hazardous seas until 5 am pdt monday 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 for rough bar until 10 am pdt monday for grays harbor bar.
gale warning from 5 am to 9 pm pdt monday 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 from 6 am monday to 5 am pdt wednesday for admiralty inlet-east entrance u.s. Waters strait of juan de fuca.
gale warning from 3 pm monday to 2 am pdt tuesday for northern inland waters including the san juan islands.
small craft advisory from noon monday to midnight pdt monday night 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 from 6 am monday to 5 am pdt tuesday for puget sound and hood canal.
Incoming 00z guidance is similar to previous solutions in showing high pressure over the region tonight weakening and shifting eastward while a vigorous frontal system offshore approaches the area. The front will move through the coastal waters late monday afternoon and through the interior monday night. The front will bring rain and breezy to windy conditions to the area and a burst of heavy snowfall over the mountains. Following the frontal system, west to northwest flow will develop, turning the precipitation showery and forming a convergence zone over the central portions of the interior lowlands. Winds will slowly diminish later tuesday.
With short term and mesoscale models showing 8-14 inches of snow in the cascades monday night through tuesday morning, a winter weather advisory was issued for the west slopes of the washington cascades from late monday afternoon through tuesday morning. heaviest snowfall will occur with the front above about 2000 feet. Convergence zone showers will linger behind the front late monday night into tuesday.
Convergence and shower activity will slowly decrease later tuesday into tuesday night as high pressure builds in from the west. Albrecht
/issued 310 pm pdt sun mar 10 2019/
Synopsis...dry conditions and clear skies are expected to continue through monday morning as high pressure aloft remains over western washington. Afternoon highs reaching the 40s to around 50 again monday. The next front will arrive monday afternoon bringing rain for the lowlands and snow in the mountains through tuesday with breezy winds. Drier weather will return by late wednesday into next weekend with temperatures near or slightly above average.
Short term /today through tuesday/...current satellite imagery continues to show clear skies over w wa this afternoon with temperatures generally in the lower to mid 40s.
Models remain in lockstep keeping the ridge overhead tonight before exiting monday morning. The incoming front still progged to hit the coast in the afternoon and making its way inland monday evening. winds ahead of the front could run breezy to locally windy...but at the time being do not see this being a significant wind event that would require headlines. Once the front passes through monday night...the associated upper level trough will make its way through the area for much of the day tuesday before exiting during the overnight hours. Both models continue to hint at the possibility of a puget sound convergence zone during this tuesday overnight period before petering out wednesday morning.
High temperatures monday expected to be similar today before taking a bit of a dip by a couple of degrees tuesday. Snow levels with the incoming front will range from 1500 to 2500 feet...so no concerns for lowland snow. Qpf and estimated snowfall amounts derived from that however do look to meet borderline winter weather advisory criteria in the cascades monday night into tuesday with storm totals ranging 3-8 inches. With this still being in the third period of the forecast and this being a borderline event...will not issue any additional products at this time but will suggest that following shifts look closely and act accordingly. All in all... Not much in the way of changes in the short term. smr
Long term /wednesday through saturday/...wednesday sees upper level ridging reclaim its throne over the area bringing a return to dry conditions into at least thursday. Models continue to diverge at this point however...with the gfs maintaining that the ridge will break down and allow for a weak shortwave to bring some precip into the cwa thursday night into friday. This would allow for an active pattern over the area with shortwaves riding over the top of the ridge...bringing more precip...into the weekend. The ecmwf however continues to amplify the ridge and keep conditions dry for the remainder of the forecast period. Once again...have split the difference between these solutions...but forecaster inclination is to lean a bit more toward the euro solution given how well it has handled the short term lately.
Afternoon highs will continue to climb in the long term...with temps getting back into the lower 50s wednesday and thursday...then continuing this warming trend into the end of the week. Current guidance is suggesting highs near 60 for next weekend...and that would most certainly be welcomed. smr
Aviation...northerly flow aloft becoming westerly. The air is dry and stable for now, but clouds will increase monday as a frontal system nears the area. Rain will develop on the coast monday afternoon and spread through the rest of the area by evening as the front arrives.
Ksea...high clouds will increase tonight and a mid level deck will arrive monday morning. Rain with a front will arrive monday evening.
Marine...a vigorous front will reach western washington monday afternoon and night. There is a gale warning in effect for the northern 2/3rds of the coastal waters, and a gale watch up for the normally windier areas for the inland waters. Winds should peak in the mid to late afternoon over the coastal waters and in the northern inland waters monday evening. Low pressure shifts inland tuesday while high pressure builds just offshore--giving northwesterly flow over the area. Pressure gradients will relax wednesday as high pressure shifts over the area. A weak front might reach the area late thursday.
Hydrology...flooding is not expected for the next 7 days.
Northerly flow aloft becoming westerly as a ridge of high pressure over the region shifts eastward. A strong frontal system offshore will approach the pacific coastline during the afternoon hours and move through the interior monday night. Low level southerly winds will increase monday along the coast and over the northern portions of the interior as winds aloft interact with the olympic mountains. The air mass is stable and dry with increasing high level moisture. Moisture will increase and deepen with cloud bases lowering from the west monday afternoon. Albrecht
Ksea...vfr conditions will prevail through monday with mvfr conditions developing monday evening as rain develops. Light winds will become southerly 4-8 kt monday morning and will increase further to 9-13 kt after 21z. Albrecht