40/70 Benchmark

Rough Friday AM Commute But Even Rougher Forecast Conservative Course Of Least Regret In Marginal Soundings While the commute this morning undoubtedly left something to be desired, it was the Friday morning forecast that was a metaphorical 30-car-pileup, which ironically enough was a fortuitous break for area commuters. Obviously the forecast for 3-6" of snowfall over northeastern Mass and much of southern New Hampshire verified as a mere 1-2" of sleet and assorted snow grains. The reason for this is quite simple. Here is the sounding, which is a profile of the temperatures in degrees celsius throughout the atmosphere, from Lawrence, MA at 1AM Friday morning. Note the tiny area of the atmosphere near freezing at around the 850mb level (5, 000 feet), right as precipitation was forecast to transition to a period of accumulating snowfall for several hours through to the morning commute. This is also evident in the excerpt of the text data from the 850MB level below, as the temperature is pinned right at freezing at this level from 10PM through 4AM, while the rest of the profile is below freezing. The forecast for 3-6" of snow was based off of guidance that implied that snowfall rates would be heavy enough to evaporatively cool this layer, while also allowing the snow to fall through it with enough haste to avoid melting. This was always a precarious position best reserved for instances in which the antecedent airmass is very cold, such as Tuesday's over performing snowfall. Ultimately, the flakes ended up being compromised enough by this layer that they were largely relegated to sleet and poorly developed snow flakes referred to as "grains", both of which accumulate extremely inefficiently. Whereas normal snowfall accumulates about 10" for every inch of liquid that falls, this type of frozen precipitation only accumulates approximately 3" for every inch of liquid, which is why an inch or two of sleet fell as opposed to between 3 and 6" of snow. Final Grade: F

Terrible forecast for this morning, but I'm sure that most commuters will forgive me considering that it wasn't nearly as miserable as feared. Culprit (savior) was a very narrow, marginal warm layer at about 5,000 feet up in the atmosphere....while that can be overcome at times, ultimately in this case there just wasn't a cold enough air mass in place to begin with and precipitation wasn't consistently intense enough. Last Tuesday, there was a very cold airmass in place beforehand, which aided snowfall. Have to grade this one an "F". Judging by my last couple of forecasts, I'm ready for spring, but Mother Nature has other ideas after next week's tease. FINAL GRADE: F

The stool-softener last night put me over 70", anyway....

Of course it nailed this stool-softener of an event, but whiffed on the blizzard getting up here.

2 hour delay for my daughter here in Methuen.

NARCAN was coating to 2" last night....should have known, but + depth change maps were still like 2-5". Oh well....1.5" of mostly sleet......heavy as fu(k.

@Damage In TollandI see what Gibbs meant now with the EURO ENSO guidance that came out today...easy winter outlook if that's right. Could still get a biggie in latter January or February, though.

Looks like Scooter was right....probably be 2-3" tops....still grainy crap. Oh well...off to bed.

0.25" here. 31.6 IP and grains

Still grainy crap....oh well, at least I'll sleep safely.

Not as safe as Weymouth

I def. had snow for a bit, but it's more sleet and grains now.

How much you want to bet I get over 2"?

I suspect that would wash out with stronger lift.

Lower thermals not an issue here at 31.8 All about the lift.

Everything is covered....all pavement.

Snow/sleet 50/50 mix...viz dropped. 32.2/31.8

Yea, maybe...whatever, at this point.

Quick updated map: Final Call:

I don't think this looks bad up here....yea, I wouldn't be thrilled in Weymouth. I should get at least 3".

Yea.

32.5/32.2 I'll be ripping by 11pm.

Lets get that baseball in on those echoes.

Two-car garage and central AC are my two musts in a home.

I will say it's too early to really use guidance...need to get past the spring predictability barrier....I just don't like the periodicity for a super-event....they usually occur about Avery 15 years or so and we aren't there yet.