Frigid air has settled over the area, with the low temperatures right now starting from the mid-20s over the western lowlands to the kids and single digits within the Columbia Basin (see under). Temperatures dropped to under zero F over some valleys east of the Cascade crest.
The entire area is loads chilly sufficient for snow proper now, there simply is not any moisture.
All of the moisture goes into California proper now. Good…they want it!
Friday and Saturday shall be usually dry over the Northwest, with loads of solar.
However Saturday night time, a moisture supply will strategy: a Pacific occluded entrance (see forecast map for 7 PM Saturday night time, black strains are sea-level strain, the entrance proven by a pink line, the near-surface temperature in colour shades).
The entrance will carry moisture and warming, however the newest mannequin simulations recommend that chilly air will maintain in sufficient in central Puget Sound to supply just a few inches of moist snow on Sunday morning (see UW mannequin forecast collected snowfall by means of 4 PM Sunday).
Plenty of snow within the mountains.
With temperatures on the sting, count on much less snow close to Puget Sound.
The European Middle mannequin goes for much less snow close to the Sound…round an inch.
The Portland Forecast Bust
Nearly as good as climate prediction has develop into, generally the outcomes disappoint.
And forecast ability isn’t extra problematic than for Northwest snow. Not solely are temperatures usually marginal for snow, however small errors in precipitation depth can have HUGE impacts on snow forecasts.
Remember that a tenth of an inch of precipitation within the type of water will end in roughly ONE inch of snow. A roughly ten-to-one ratio. So small errors are amplified.
Listed here are the snow totals from yesterday within the Portland space. Round 8-10 inches across the metropolis.
In reality, Portland’s airport obtained 10.8 inches, ensuing within the second snowiest day within the station’s historical past.
How a lot was predicted? The official Nationwide Climate Service forecast Tuesday night time was lower than an inch! (see under)
A significant problem was that the fashions underplayed the moisture circulating round a low shifting down the coast, with a band of heavier precipitation hanging round Portland (see satellite tv for pc picture round 3 PM yesterday). Onerous forecast.
