October 12, 2024

As we approach mid October, we hit the climatological average of first flakes across the Allegheny high ground and like clockwork mother nature and old man winter are on schedule.

So, to get there, we obviously need some cold air. Later Sunday, a cold front begins to set the stage

That cold front will come through with a threat of showers and storms. Some may contain gusty winds and hail. Not a widespread severe outbreak

That cold front itself is accompanied with and trailed by strong gusty winds in to Monday as colder air continues to push in on a west and eventually northwest flow.

Wind Gust off the 0z ECMWF. The ECMWF (euro) is a bit more impressive than other modeling. Starting the map at Sunday morning.

Thats accompanied by colder temps aloft and at the surface.

•2m Temps off the 0z ECMWF below

•The air aloft begins to support frozen precip across the WV high ground first. If there is enough precip left initially Monday evening.

Let’s look at the 850 temps. Essentially the Wv tops. This is the best method to forecast temperatures for those tops. Not the 2m temperature maps. They are not gridded on a scale to capture those areas the best.

•the 0z ECMWF 850 temps below. Essentially temps at 5000′

• and a look at 6z GFS 850 temps

When it’s precipitating across the high ground, your afternoon temperature DO NOT stray far from the 850 temperatures. The there is very limited diurnal impact. If you see temps at the surface trying to pop up above that 850 temp much…Boom, expect a snow shower to rapidly bring things back to equilibrium. So when you look at that, you expect afternoon temperatures Tuesday and Wednesday to run upper 20s, low 30s above 4000-4300′. Any rise to the mid 30s, rapidly knocked back.

Ok, let’s look at the precipitation type off the modeling.

•0z ECMWF below

•6z GFS below

It’s possible flakes and a coating could occur across the WV high ground Monday p.m, Tuesday morning. The better chance of whitening things up will occur through Tursday pm in to Wednesday.

Snowfall off modeling. Again everyone in the colored in parts of this map will not see accumulation. It’s not a mesoscale grid.

• 0z ECMWF

•6z GFS

Upslope zones

2500-3000′- coatings that rapidly melt off

3000-3500′- .5 to 1.5″

3500-4000′- 1.0 to 2.0″

4000’+ 1.0 to 3.0″

An example of how you may expect this to play out “IF” modeling holds as it currently looks. All dependent on how the piece of energy works out on Tuesday. In a marginal early season setup. Elevation is big.

A very often used, over used and always failed statement that’s repeated over and over and over.

The ground is too warm for snow to stick anywhere. When you get up in the Wv high ground, where air temps go below freezing, accompanied by 20-30mph+ winds. How long does it take to freeze the upper light uninsulated ground surface made up be fallen leaves, dead grasses, conifer needles, etc…getting that surface cold enough to stick with temps at and below freezing occurs rapidly. It’s only after you accumulate that the ground warmth in those locations have the melt from underneath impact as the snow begins to insulate that and let’s the ground temps melt. So, once things initially stick, limited melt until you get a bit of accumulation.

In areas with marginal low to mid 30s temps, lighter precip. Sure the ground temp+ air temp will rapidly melt whatever falls. It’s a different game early and late season across the highest locations in the Allegheny region. You can book learn until the cows come home, but getting out and experiencing, documenting first hand is a really good teacher in how that works.

Let’s see how things continue to evolve in this early season cold unstable incoming airmass. Changes can definitely occur and the setup falls apart some. Drier, etc

as of now liquid output Tuesday a.m to Thursday a.m, most of which would fall in snow form across the WV high ground with near and below freezing temps

•0z Euro

•6z GFS

Ratios while not great, are also a bit better on top. 8-12 to 1. Lower during the day, bit better at night. Even with cloud cover, temps near freezing, accumulations will be more compact and be a bit sticky during the day, lighten up, lighter, powdery at night.

Anyways, not a big deal other than flakes and coatings potentially for most, across the WV tops a brief look of winter midweek. Do not go buy TP and bread.