ZCZC SPCSWOMCD ALL
ACUS11 KWNS 132005 
SPC MCD 132005 
ORZ000-WAZ000-140000-

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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