SPC MD 61

SPC MD 61

MD 0061 CONCERNING HEAVY SNOW FOR NORTHWESTERN OREGON AND FAR SOUTHEASTERN WASHINGTON

Mesoscale Discussion 0061
NWS Storm Prediction Center Norman OK
0205 PM CST Sat Jan 13 2024

Areas affected…Northwestern Oregon and far southeastern Washington

Concerning…Heavy snow

Valid 132005Z – 140000Z

SUMMARY…Periods of heavy snow with snowfall rates between 1-2
in/hour will continue into the mid/late afternoon hours. Freezing
rain remains probable through the Willamette Valley.

DISCUSSION…Bands of moderate to heavy precipitation continue to
overspread the Pacific Northwest ahead of an approaching mid-level
wave. So far, much of this activity has been driven by warm
advection in the 850-700 mb layer, but some uptick in precip
coverage and intensity appears likely as lift associated with the
vorticity maximum and attendant mid-level jet overspreads the
region. The 18z SLE sounding sampled a deep saturated layer from the
surface to around 450 mb with a somewhat shallow (~100 mb deep) 1-2
C warm nose centered at about 850 mb/3 kft. More recent KRTX CC
imagery indicates that this warm nose remains in place. Locations
above roughly 3 kft should continue to see moderate to heavy
snowfall through the mid/late afternoon with snowfall rates between
1-2 in/hour possible. The shallow sub-freezing layer below ~3 kft
will support a continuation of freezing rain for some locations –
primarily through the Willamette Valley. However, localized
fluctuations in the shallow warm layer may promote variation in
precipitation types between freezing rain, snow, and sleet.

..Moore.. 01/13/2024

…Please see www.spc.noaa.gov for graphic product…

ATTN…WFO…PDT…MFR…SEW…PQR…

LAT…LON 44192375 44442423 44642418 46032410 46212399 46392363
46352107 46182067 45762021 45001991 44212004 43732038
43532087 43462157 43772338 44192375

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