How Important is December Snowfall?

[CT Rain]

Partially to rile people up and partially out of curiosity I took a look a look at previous Decembers with less than 6" of snow and less than 1" of snow at BDL. With our luck this is where we're heading.

6" or Less in December

- Happened 37/93 Winters

- Of those winters 7/37 had above normal seasonal snowfall

- Of the 37 winters the average seasonal snowfall was 32.7"

1" or Less in December

- Happened 10/93 Winters

- Of those winters none had above normal seasonal snowfall

- Of those 37 winters the average seasonal snowfall was 24.4"

What's remarkable is that the average snowfall for December is 8.4" at BDL so 6" or less for the month at BDL probably says just as much about the overall winter pattern as it does about just having a crappy month.

So for all the posts that say, "don't worry... it's only December 10th" when the next 7 days don't look all that great... there actually is something to worry about if we can't get some snow in here over the next 3 weeks!

[Damage In Tolland]

:weenie:

[Kbosch]

Nice post. I can't believe not getting snow in a month where you're supposed to get some measurable snowfall makes having a lesser total for the winter a debatable topic. Your stats are not surprising.

[CT Rain]

:weenie:

You'll have lots of weenies to chuck if this winter turns out to be a total and epic fail

[CT Rain]

Nice post. I can't believe not getting snow in a month where you're supposed to get some measurable snowfall makes having a lesser total for the winter a debatable topic. Your stats are not surprising.

BDL averages about 46"... in December about 8". I was a bit surprised that the avg snow following a December of less than 6" (there were a lot of 3-6" Decembers in there) was 33". It definitely says more about the pattern than just having an unlucky month.

[CoastalWx]

Partially to rile people up and partially out of curiosity I took a look a look at previous Decembers with less than 6" of snow and less than 1" of snow at BDL. With our luck this is where we're heading.

6" or Less in December

- Happened 37/93 Winters

- Of those winters 7/37 had above normal seasonal snowfall

- Of the 37 winters the average seasonal snowfall was 32.7"

1" or Less in December

- Happened 10/93 Winters

- Of those winters none had above normal seasonal snowfall

- Of those 37 winters the average seasonal snowfall was 24.4"

What's remarkable is that the average snowfall for December is 8.4" at BDL so 6" or less for the month at BDL probably says just as much about the overall winter pattern as it does about just having a crappy month.

So for all the posts that say, "don't worry... it's only December 10th" when the next 7 days don't look all that great... there actually is something to worry about if we can't get some snow in here over the next 3 weeks!

That I agree with. If December sux, than we could have a problem. Weenies crossed.

[CT Rain]

That I agree with. If December sux, than we could have a problem. Weenies crossed.

Given the strength of the Nina... if December sucks and we wasted 3 or 4 weeks of good blocking I really think we're screwed. I still think we get a real nasty torch of strength and duration sometime in Jan or Feb so that is going to be quite unpleasant if we weren't able to cash in on a solidly below normal month.

[HoarfrostHubb]

Well, I see the point of your post, Ryan, but you could have one 6.1" storm in Dec and have a stinky winter...

I wonder if similar is true for BOS and ORH?

[Kbosch]

BDL averages about 46"... in December about 8". I was a bit surprised that the avg snow following a December of less than 6" (there were a lot of 3-6" Decembers in there) was 33". It definitely says more about the pattern than just having an unlucky month.

For sure. That 7/37 is a great number. Great research.

[nzucker]

Given the strength of the Nina... if December sucks and we wasted 3 or 4 weeks of good blocking I really think we're screwed. I still think we get a real nasty torch of strength and duration sometime in Jan or Feb so that is going to be quite unpleasant if we weren't able to cash in on a solidly below normal month.

Exactly, we're probably going to develop a raging -PNA at some point this winter in late January or February that gives us torch conditions for a few weeks...we've seen the progression to a strong western trough in a lot of Niña winters like 88-89 and 54-55. If we don't capitalize on the cold conditions in the first half of winter, it may get too warm later on as the -PNA develops and the AO/NAO blocking starts to relax with the stratosphere turning cold and the PV strengthening in mid-winter.

[ORH_wxman]

Well, I see the point of your post, Ryan, but you could have one 6.1" storm in Dec and have a stinky winter...

I wonder if similar is true for BOS and ORH?

I'll do the numbers for ORH in a bit

[NECT]

Not based on actual research, just what I *think* I remember. December often sucks. When it does snow, it is often followed by rain and fog in these parts (not so much the Berks and N Worc. County). I'll wait for Jan. & Feb (and maybe a litlle bit of March).

[HoarfrostHubb]

I received almost half my snow in Dec last year so what? Stats are a poor mans way of making average seem Great. Wonder if you ran a linear correlation for all years what the coefficient would be. It's all relative. Just look at 77/78

What was so special in 77/78?

[weatherMA]

But I thought last weekend we were guarenteed 2-4, 3-6" region wide with the clipper?

[OKpowdah]

good thread

[ORH_wxman]

For ORH, I used the threshold at 9" or less for December which is less than 70% of the December avg. The numbers are not pretty when December stinks...esp in a non-Nino...you can see most of the best recovery years were Ninos.

Since 1950:

Year.....Dec snow....seasonal snow

1950........6.6".............33.0"

1952........3.8".............39.5"

1953........1.7".............31.2"

1954........6.2".............21.2"

1955........2.7".............85.4"

1957........2.2".............97.5"

1959........8.5".............66.5"

1973........0.9".............41.0"

1979........2.1".............26.6"

1980........6.8".............43.0"

1984........7.7".............45.6"

1986........4.9".............93.6"

1988........5.0".............28.1"

1990........5.3".............35.9"

1994........3.2".............24.9"

1998........6.0".............46.3"

1999.........T................30.2"

2006........1.1".............49.7"

Avg..........4.2".............46.6"

[Ginx snewx]

What was so special in 77/78?

3 inches in Dec 63 total

[Ginx snewx]

Will what is ave for Dec and total ave at ORH

[ORH_wxman]

Will what is ave for Dec and total ave at ORH

Yeah I should have put that in there...I forgot, oops.

Dec avg: 13.4"

Season avg: 69.1"

[nzucker]

3 inches in Dec 63 total

Yeah but those are El Niño patterns where you're much more likely to have a blockbuster February, which is climatologically the snowiest month for many of the coastal stations. That's a different story since a weak/moderate El Niño, specifically if west-based, tends to produce a lot of coastals later in the season which really causes snowfall totals to mount. This is much harder to get in a strong La Niña...January and February often suck, which leaves you to benefit from March, and then you're basically talking about three weeks of marginal events to make up for two bad months with spring kicking in quickly. March 1976 and March 1955, two good analogs for this winter, were nothing to write home about as the pattern was pretty warm for a lot of the East.

[nzucker]

How much have you had this year so far Will? Are you up past 1"?

[ORH_wxman]

How much have you had this year so far Will? Are you up past 1"?

I havent even had measurable yet. I'm still at a trace.

[Ginx snewx]

Yeah I should have put that in there...I forgot, oops.

Dec avg: 13.4"

Season avg: 69.1"

So in bad Dec years you only get 10% of your ave final total snow ,in Dec, an average Dec would give you roughly 17% of yearly average.

[ORH_wxman]

So in bad Dec years you only get 10% of your ave final total snow,

???

In bad Decembers on that list we average 46.6" for the season which comes out to 67% of average.

[OKpowdah]

???

In bad Decembers on that list we average 46.6" for the season which comes out to 67% of average.

I think he was saying in bad Decembers, you only get 10% *in December* of the seasonal average

[Ginx snewx]

I think he was saying in bad Decembers, you only get 10% *in December* of the seasonal average

Yep hit send too soon, edited it.

[Ginx snewx]

If you call good Dec has 18 or more what is your average final.

[ORH_wxman]

I think he was saying in bad Decembers, you only get 10% *in December* of the seasonal average

Oh right...well that makes sense. A crappy month is going to be a small percentage of the total snowfall.

This Nina isn't even playing by the rules right now anyway...so I think analogs will be tough to use. Its also still relatively early in this month. If we get a 10" snowstorm at some point in the next 3 weeks, then we can throw out all the bad December stats.

[skierinvermont]

What's interesting is that both of your stats show (BDL/ORH) that even though the poor Decembers were only 3/6" below average on average, they were followed by seasons with 14/23" below average snowfall.. so clearly the poor pattern continued into the rest of the year. The deficits aren't juts due to December, they actually got much larger. That's somewhat surprising to me, it actually seems like a decent predictor.

[Ginx snewx]

Oh right...well that makes sense. A crappy month is going to be a small percentage of the total snowfall.

This Nina isn't even playing by the rules right now anyway...so I think analogs will be tough to use. Its also still relatively early in this month. If we get a 10" snowstorm at some point in the next 3 weeks, then we can throw out all the bad December stats.

What I like about this whole post is the three weeks part.