Time and Day: 0630 Sunday
The Snapshot: I have no idea what will happen today. Snow
continuing Monday.
Current Observations: Barely
an inch of new snow overnight, temps are in the high 20’s at all sensors this
morning. It is currently lightly snowing and the barometer is steadily
dropping.
The Science: A well-defined warm front with a
trailing cold front embedded in strong westerly flow is rapidly approaching
Washington State. After the warm front passes midday, the trailing cold front
will sag a bit south and become stationary for several hours. There is plenty
of moisture involved, so there’s no question that we will see lots of water in
the next 24 hours. The uncertainty lies with how far the trailing cold front
will sag south, and where it will hang up when it becomes stationary. Models
have free air freezing levels peaking around 5,000’, but they also show Stevens
Pass staying in the snow band almost all
day. Thus I have little confidence in predicting exact snow amounts by Monday
morning.
Forecast models have
consistently showed cooling Monday morning with continued precip, albeit
becoming light during the day. The next much-discussed and interesting storm
arrives Monday night. A deep low pressure system deepens as it makes landfall
and brings a sharp cold front with it. There are several mechanisms at play to
facilitate heavy precipitation, and freezing levels look solidly in our favor
for this event, for now. Day 2 snow amounts will happen in two main pulses, early
Monday morning and late Monday night.
The Long Range: After what looks to be a good snow producer
Monday/Tuesday the moisture turns off on Wednesday. Cool northerly flow aloft
will bring sunny and cold conditions for Thursday and Friday.
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24hr Precipitation ending at 4am:
Today 24hr water: 2.0” Snow:
6-16”
Tomorrow’s 24hr water: 1.0” Snow:
10-12”
Trend and Timing:
Snow showers will become moderate to
heavy mid-morning Sunday, with a probable transition to rain midday. By dawn
Monday morning the precip should be snow again.
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24hr temperature
ending at 4am:
Low: 28 High: 34
Free air freezing level: 4-5,000’
Trend and Timing:
A steady warming trend will occur on Sunday,
peaking Sunday afternoon and cooling back down by Monday morning.
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24hr Winds (mph) ending at 4am:
Base: W 10-15
Ridge Top: WSW 30-40
Trend and Timing:
Winds will ramp up by midday Sunday
and remain strong and gusty overnight.
DV
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