OceanStWx

Contours are probability of (in this case) updraft helicity greater than 75 m2/s2. With the individual model swaths of 75 plus shown. A good discriminator for supercell structure. The same product for 150 m2/s2 is fairly impressive too.

Tip is right about one thing, measuring as close to the end of the snowfall as possible is ideal (and recommended by the way). But if you think about this all in an impact sense, what makes more sense: plows waiting until the snow stops and removing snow, or plows nearly continuously keeping roads clear? I would argue a plow operator is much closer to observing the 6 hourly snowfall amounts than the 24 hourly. It's one thing we've discussed internally about the 6" in 12 hours vs 9" in 24 hours warning criteria. If anything the lighter, longer duration 9" in 24 hours is more impactful because road crews are out longer.

Starting to look that way.

Obviously a long way to go, but even a moderate snow storm next week would give PWM a shot at top 3.

I mean there is probably a fair chance that sea scroll era measurements were just depth increases. I sincerely doubt some knickered colonist was clearing a patch every 24 hours to measure new snow.

Well the observation is the airport, not downtown anyway. So Winthrop is far more representative of that than downtown. Of course many argue about Tarmac observations and not where people live, but that's the way it's done. ASOS is BOS officially, and Winthrop is an acceptable distance from the ASOS and has an observer. Outside of Winthrop their closest active site is Franklin Park Zoo, and that's way too far away for climate purposes.

Hmm, 2.75" with 27" on the ground for 3/14. That does seem suspiciously like a snow core not a melted precip.

Accuweather troll farm in Wilmington?

You do see that happen all the time. Our hydrologist goes through CoCoRaHS every morning to set those to missing.

It's pretty hard to slant stick a rain gauge, but people do it.

Some of it may be removing it for the final snow map purposes. Even if your report is accurate, if it sticks out enough from surrounding obs you'll get a pretty ugly bullseye with the mapping and it helps to smooth things to remove it. The only way to do that is by taking it out of the PNS (because the software pulls the metadata at the bottom to create the map). It may not necessarily be a commentary on your reporting.

Forgot MWN too (but they aren't climate). They are 6 hourly, but a crapshoot with the wind. We have a very old group of Coops up here, and they are pretty much uniformly walk out at 7 AM and measure snow. We know this because some bad mornings they say they don't have snow just yet because they haven't walked outside (too icy, windy, cold, etc). But it's also hard to convince someone to volunteer their time to meticulously measure how much snow falls. It's a commitment to be around all the time and have a back up for when you're on vacation.

Obviously the big issue is melt/compaction with the once a day measurement. If you aren't checking for the max depth, you are likely to miss it. If you work from home it's easier to check frequently. But say it snows in the morning, you head to work, it stops at lunchtime, you come home, sleep, get up and measure at 7 AM the next day and the whole time temps were around freezing. You could "lose" a bunch of snow in that case. This is why our spotter training focuses mainly on snow (sorry @weatherwiz)

Most offices are going to have at least two airports measuring every 6 hours, to keep consistent with old WSO stations (like PWM and CON, BOS/BDL/ORH/PVD, etc).

I know up here we have 5 climate sites. PWM and CON have paid observers measuring every 6 hours, GYX obviously is staffed round the clock and does 6 hour measurements, and MHT as far as I know reports their 24 max snowfall at midnight (AUG doesn't have snow obs )

If the mets are dedicated posters/lurkers on the board they know the slant stickers from the good obs. Some of you are so neurotic about snowfall measurements that I know you wouldn't artificially inflate your totals.

I think he gave you the 1st number in Merrimack too. ME1.

PWM actually has 2.5" officially since midnight, so that's 9th snowiest.

I don't know why it drops out of the PNS sometimes.

Looks like PWM has climbed into the 9th snowiest March already. This is also probably the 2nd snowiest week in March.

In fairness, in my hierarchy of reports I put general public before social media. In extreme cases when someone doesn't go to spotter training (@dendrite), we'll just give them a spotter number and enter it on our own when we see the report on a message board.

This one's going to knock me out of the office snow pool. I threw a 90" guess this season, and GYX is currently at 81.5" before this storm is counted.

Our CON observer was like 9.5" on 0.45" in the 6 hours before 7.

I mean QPF is pretty bunk from models in general, but can be either too broad (this storm) or too terrain influenced. Interesting to see even at 18z, the NAM had a low level inversion around 3-3.5 kft that could have focused some orographic differences, but the GFS had none (or nothing as strong as the NAM).