OceanStWx

I think we've got one more window, like 15-17z. Models are hanging back that f-gen now, and it should sweep across southern NH.

There are calculators online too. But if you want a general rule of thumb, add two to the dew for every degree you drop the temp.

As an addendum, we usually assume that max lift occurs at 700 mb, which is why we suggest we want the DGZ around that level. Of course max lift can occur at many levels, so as long as it bisects the DGZ it can snow heavily. There is just a lot more that can happen to a flake the longer it falls (evaporation, fracturing, riming, etc).

Wet bulb is 34-35 from BOS to BDL, so if it is +SN I don't worry about accumulation. If it stays 1SM, that's when it could be trouble.

Either way we nuke our snowpack?

I think it's really bitten us this last week. We've really struggled to get the snowfall forecast in the right ballpark around warning criteria.

A little more CCB now, I think the trof is more Currier and Ives mood setting than anything else. If you look at the 250 winds, the trailing jet streak it's a little less progressive today than it was yesterday or the day before, so the CCB gets going sooner. I would really like to see an event with a DGZ below 500 mb though.

Let's call that an upper bound solution.

Lacking a Bufkit point for DAW, I think MHT it a good proxy for you. Rips between 06-12z (probably close to 1"/hr), then lulls followed by lighter inverted trof snow the rest of the day.

At least it will be roaring easterlies above the treetops instead of roaring southeasterlies.

If it's ripping heavy snow it will accumulate. But we did knock down ratios to below 10:1 in that area to account for some loss in depth to warm boundary layer.

Pope Pummeler?

They do close, but late in the game. A "classic" event you have the WAA band move through and then the mid levels close somewhere around MTP and continue northeast and the storm does a bit of a pause and pivot with the CCB. This storm is moving almost due east, so we don't really get a pivot because the WAA doesn't keep moving through but like Will said it does allow eastern New England more time to get the CCB involved. But because the mid levels are always moving away from the coast, any delay in deepening and the CCB is toast.

For me it's really that the shortwave is deamplifying as it approaches, and going into the day Saturday the strongest forcing continues east with the WAA and there never is really a big push towards establishing that CCB based on upper support. But I was able to thump 6 to 8 inches in the 6 hours between 06-12z Sat.

Granted it looks like the storm of the season for many, but I also feel like I'm edging out onto the runway with my flares. I feel like guidance is probably too juicy after 12z when forcing starts to taper off and dry air (especially up here) starts to sneak in, but I'm seeing some good 6 hour forecasts popping up with our internal collaboration. I never like to see huge forecast swings based on one set of model runs.

Yeah the shortwave and trof are the features. Not really surprising, but the GEFS/EPS both are saying the same thing - you want a stronger lead wave followed by a weaker wave that kicks out of the western trof.

I can't remember, I think we replaced it. But now that I look back at the data it seems to do some weird stuff in July every year. So there might be a local siting issue. And for those unaware the +/- 2 degree tolerance is because ASOS is just an aviation tool. It's not really meant for precision measurement of temps. If the airlines all of a sudden required temps to be within a half degree, then that would become the new ASOS tolerance level. But since they don't care, we're left with that wide range.

PWM did the same thing. I think we had a record warm summer month, that didn't feature any blazing heat. It was just a steady +2 every day.

At least in the MPV example, it's so far off you know it's likely bad data. We have to jump though quite a few hoops to change ASOS data for the climate sites though. ASOS is king, and we really need hard evidence it's not to get it changed or thrown out. So if the observer sees snow but the ASOS doesn't, the climate is recorded with the ASOS "0". Likewise on temps, if it's "just" 2 degrees we're obligated to keep it.

Yeah, that pretty much covers it. We've had the techs out a few times to check calibration of temp sensors. Usually because it's within the +/- 2 degree threshold nothing ends up getting done.

-47

12z sounding warmed 850s 7 degrees, but 925 stayed the same. Not surprising, but the low level cold took longer to push out.

BOS did hit -10, first double digits below zero since 1957.

PVD down to at least -9, if the stats are correct if they can sneak down to -10 that would be the first time since 1981.

I saw a -59 at Jackman for the lowest non-mountain top wind chill of the event.