LATE WEEK SNOW POTENTIAL

/ alleghenymountainsweather

Late week snow potential

November 16, 2024

A look at the WPC outlook for heavy snow potential late week

https://www.cpc.ncep.noaa.gov/products/predictions/threats/threats.php

A developing low pressure in to the lower lakes Wednesday in to Thursday will bring initially a rain to snow setup. The transition to snow over the high ground should occur rather rapidly later Wednesday night in to Thursday.

How things evolve late Thursday in to the weekend with the backside upslope potential will be the determining factor how significant of an event this is. The placement of the deep upper low, the duration will determine the qpf of the event. The GFS and Canadian are a much more prolonged snowy event vs the Euro.

The GFS below

The Canadian below

The Euro

The amount of precip output variance off the GFS and Euro is significant.

The GFS 72 hour Sunday a.m which covers the brunt of the initial snow and upslope event. Putting out in excess of 2″ of liquid, which would be snow across the high ground.

The Euro much much less.

Forecast likely will trend colder as we get closer.

Let’s look at the 850 temps. Essentially the WV high ground temps

Thursday morning off the GFS , that’s -7c or around 19-20° F. That’s not a borderline marginal temp setup. From Thursday through Sunday -4 to -7c is the range through the period. As long as it’s precipitating, there is no daytime diurnal across the tops. You would expect temps above 3500′-4000′ feet to run in the 20s for the event. 2500-3500 27-34° with the maxes occuring during precipitation lulls in which the GFS limits and the Euro gives more opportunity for slightly “less cold” surface conditions. Snowfall can occur down to the lower elevations with
1- heaviest intensity 2-nighttime periods.

The difference in the 2 models is the difference of a 4-8″ upslope snowfall event vs a 10-20″+ snowfall event. The Canadian laying in the middle for the typical favored upslope areas. That tails off east side.

Accompanying the snow, strong NW winds

off the gfs

winds gusting 30-45+mph. Strong temps, well below freezing temps. It takes minutes to get stickage going across those tops in those scenarios. A repeated bogus statement all the time by many is “ground is too warm”. Once you get several inches of accumulation, the marginal warmer ground will cause some underneath melt. That’s to be expected. After a week of rain and 30s, that ground is not that warm at present.

If the GFS scenario plays out, Whitegrass xcountry skiing is in business next weekend. Significant snowfall, significant blowing and drifting.

I’ll avoid attaching model snowfall maps

1- due to high variance

2- long ways out

More thoughts will occur as we go day to day towards the event.

Leave a comment