December 27, 2019

/ alleghenymountainsweather

December 27, 2019

Dec 27(Fri)

The theme has changed. From a dry air mass, tranquil, still air mass, has now seen a increase in dew points and breezy conditions and this continued into the overnight. This ate some residual valley snow that remained.

Bittinger 2nw Valley

MIN[30.1]—MAX[49.6]—AVERAGE MEAN[39.8]—TRUE AVERAGE[40.2]—PRECIP[T]

Snow depth Average 2″ in valley, trace up high

Garrett College

MIN[37.4]—MAX[51.4]—AVERAGE MEAN[44.4]—TRUE AVERAGE[46.1]—PRECIP[.01]

Canaan Heights/Davis 3SE

not reported yet

Climate Reference Network Canaan

MIN[42.5]—MAX[50.6]—AVERAGE MEAN[46.6]—TRUE AVERAGE 47.7]—PRECIP[.01]

Cabin Mt at Bald Knob

MIN[42.4]—MAX[47.7]—AVERAGE MEAN[45.0]—TRUE AVERAGE[45.4]—PRECIP[.02]

Cabin Mt-Western Sods

MIN[42.8]—MAX[47.1]—AVERAGE MEAN[44.9]—TRUE AVERAGE[45.7]—PRECIP[0]

Spruce Knob

MIN[40.6]—MAX[45.0]—AVERAGE MEAN[42.8]—TRUE AVERAGE[43.3]—PRECIP[0]

Snowshoe

MIN[42.6]—MAX[46.9]—AVERAGE MEAN[44.7]—TRUE AVERAGE[44.9]

Canaan Valley Refuge

MIN[24.4]—MAX[51.6]—AVERAGE MEAN[38.0]—TRUE AVERAGE[41.1]

7Springs

MIN[46.2]—MAX[52.0]—AVERAGE MEAN[49.1]—TRUE AVERAGE[48.2]

Cumberland Airport

MIN[33.8]—MAX[49.1]—AVERAGE MEAN[41.4]—TRUE AVERAGE[43.3]

The Valley vs Cabin Mt

Canaan area temps

Comparison view

RTMA

Radar

Satellite

Flow

Surface features and 500mb height anomalies and flow

Pics today

Bittinger area

This is mainly the Bittinger 2nw Valley area with exceptions. The fascinating micro climates. Snow cover in a sheltered valley that refrigerated itself prolonging its existence well beyond surrounding areas.

ok, timeout for the next image. A terrific example of how this works. Again, light winds are key, in which we have seen up until this afternoon. Low dewpoints also aid in snow preservation, which was the case up until this afternoon. So picture a 50° dry airmass, low sun angle. It doesn’t melt snow fast. A steep hillside, covered in snow. No wind to scour away the cold coming off the snowpack sinking to the lowest point, in this case the Valley bottom. The temps up high do melt the snow slowly, while the Valley sees little to no melt with the low dewpoints. As dewpoints increase, the cold air still sinks to the Valley as cold air does, however it’s less successful in preserving it’s own pack. Temps however remain much colder than up higher. As the pack leaves up high, and melts off, the snow line works it’s way down the hillside. The cold air to come off the pack becomes less and less, the Valley still holds cooler, but less so and with dewpoints and lights winds in play, the effect becomes less and less and the Valley begins to melt off. Which was the case, especially after nightfall when the winds held up. Here is a pic that is a great example of this

Above that line, snow is now gone, below, it’s still chilling itself. Less successful with higher dewpoints and light winds, but still to a point works the same.

Deep Creek Lake area

Winter where art thou???

The continuation of the SW flow aloft has put a halt on winter across the high ground. Over the next few weeks, the hope’s of sustained winter look bleak. What is beyond that period is anyone’s guess. If history is the example, January may have little in the way of sustained winter. With a large pool of very warm water off the southeast coast, into the gulf, the dreaded 500mb ridge sits in place like a giant. At times it gets attacked, weakens, but feeds back and builds over those warm waters. This causes a storm track to our west, in some instances far enough west the rain even misses to the west and other instances we get the rain to snow scenario. A few in the area, mainly north in Garrett, and north and east into the lower elevations, some cold air can be left in tack from departing cold to allow for some ice. Upcoming, that doesn’t look to be the case without cold highs to our north.

Of late, the low elevations have been colder than the high ground. While many think this is unheard of, it is not at all uncommon in this pattern. It’s in fact, typical when this pattern occurs. Just to pull out one year as an example that had a very similar setup, December 1936. The SST(sea surface temperature) anomalies had a pattern very like this current December. Let’s look at that

1936 Reanalysis

Current SST anomaly

The color scale/scheme is not the same, but the large warm pool that everyone loves in the northeast Pacific(those who love cold in the eastern U.S, is that everyone?)to pump the ridge into Alaska and the western U.S and dig the trough in the east exist. Warmth extending from southern California, Mexico westward. A resemblance of a weak modoki nino. Cold waters east of Australia. A bit of a cool pool east of Hawaii. Those things alone in the Pacific look great. The caveat, the waters off northern California, into Oregon, nearly identical . Only my opinion, that allows the lows to get cutoff, and our big blocking southeast ridge sends these systems west. With allow brief hits of cold that follow behind.

A look at the December 1936 temps

This December to date

Holy smokes, a few minor variations, but that’s a lot alike. We have the colder air on the east side of the mts then, in a similar setup. Let’s look at the last 2 weeks,

For those in the Wv high ground, it’s hard to imagine some areas the past 2 weeks in the region have seen below normal temps.

Bald Knob at Canaan at 4350′ vs Cumberland at 774′

In some of the fascinating microclimates, a decent snow cover remains today. Example here near Bittinger, in Garrett County, just today at 2550′. This is a product of a sheltered valley holding cold in much the same way as a supermarket cooler works. The low dew points, calm winds, short days, these type areas do well in holding cold. Case in point below:

However this will be going away over the next few days ahead of the brief colder air coming next week. Why is it brief. I should say, likely brief as mother nature can yet fool the models. Today’s 12z runs of the 500mb heights is down right ugly for sustained winter. 585-591 off the Florida coast doesn’t bode well for Wv high ground snow. Pa north, it can.

12z ECMWF

Look at that continued large ridge. If that is the case. You will get a day, or 3 of winter, then the SW flow rapidly takes over. The GFS has this Ridge, although is a little less bullish on it.

The culprit in my opinion

The feedback over the warm waters in the gulf and southeast coast accompanied by the ring of cold in the Atlantic. That same ring of cooler water was nearly in the same location in 36.

What then occured in January 1937?

last night’s run of the ECMWF weeklies looked like this for the overall mean of the next 46 days. (Fortunately this model has not been good)

What exactly did January 1937 look like

Canaan did not have an official coop in 1937, but reports are, no measurable snow occured during that month. A station did occur at Stony River Dam, and it does have missing data, only a trace there was recorded. This is the least snowiest winter month in our areas recorded history

A little more from 36

November 1936, November 2019….the coldest area is centered in much the same area.

    All that said, no pattern will match up 100%, and other factors can take over, and things such as a sudden stratospheric warming event can come in to play and alter what happens this season. Not trying to be a Debbie Downer to winter lovers(me included) . We still get some snows, but things at present day do not look promising for anything sustained near term at least…

    Currently all the teleconnections do not look favorable for sustained winter. EPO ehh maybe the hope,WPO…,the NAO,AO,PNA natta

    The near term:

    Before Jan 1 does arrive, we do got a shot at some snow that goes into Jan 1. The GFS, Canadian are similar while the ECMWF gives winter the middle finger again.

    Wednesday may be a go day for resorts to make snow…

    12z GFS temps

    12z GFS snowfall

    12z Canadian temps

    12z Canadian snowfall

    12z ECMWF temps

    12z ECMWF snowfall

    Interestingly enough, the long range GFS pumps out quite a bit of upslope snows days 8-16. Color me surprised if it occurs…just keeping some hope for the winter lovers….if the SE mega 500mb Ridge breaks, we are back in the game…..if not we are the Steelers without Roethlisberger hoping someone else can play QB.

    Another fascinating local climatology event at play. While not cold enough for ice, those same areas this Sunday look to remain much chillier than the Wv high ground and west of the mts….the same almost identical repeated boundary.

    12z 3km Nam temps

    THINK SNOW, SNOW DANCE, PRAY, DO A PAYBACK IN THE STORE….AT THIS POINT, IF YOU WANT SNOW, TRY ANYTHING. Yes, I was yelling. Desperate times call for desperate measures…

    Part 2 tomorrow where Feb and March went in 37

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