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Boats_are_fun t1_ja9ovjo wrote

Paging u/cloudboy

Edit: u/TheCloudBoy

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TheCloudBoy t1_jaazcoh wrote

Why hello haha, I hope I can be of some assistance here! So a few thoughts:

  1. Your suspicion on a convergence to higher QPF (liquid precip equivalent) has certainly occurred over the past 36 hours for portions of NH. This has been focused in three areas: SE exposures of the Whites, eastern NH near the inverted trough axis, & ESE exposures along the Mondanock Region
  2. Big reason for the uptick in precip is from convective bursts set to form along the inverted trough axis forming in the Gulf of Maine and extending into ME. My thesis focused on similar events and found mesoscale models are far better resolving this (obviously) than the GFS or ECMWF.
  3. I'm not surprised a number of TV stations are lazily ripping whatever the ECMWF forecasts without really trying, this is a major gripe I've had lately.
  4. Snow ratios are going to vary with the event by location, so using the 10:1 static ratio will get you into trouble here away from the Seacoast & lower Merrimack Valley. Lift through the dendritic growth zone isn't wildly impressive but I can absolutely see snow ratios average to 12-15:1 across interior NH, especially northern Strafford, all of Carroll, and the Whites.
  5. We've been all over this at the company I work for, here's the gridded forecast we were giving clients this afternoon. This is a dynamic ratio forecast using a superensemble approach with an emphasis on the mesoscale model data. I'm convinced locations in/north of Effingham get pasted and someone comes close to 12" there. We starkly contradicted the NWS in a number of areas and feel confident we will be successful in doing so: https://imgur.com/gallery/cP6GD3r
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[deleted] OP t1_jab0l2k wrote

[deleted]

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TheCloudBoy t1_jab11q0 wrote

Yeah I'm very interested in this as well! It's consistently not been too keen on this inverted trough taking shape & lingering, which is more or less half the puzzle to getting these bursts of snow going.

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DeerFlyHater t1_ja9btdo wrote

You want to see downplaying, check the Apple Weather app.

Says I'm supposed to get 1.4" here by Squam Lake. NWS says 6-7.

I'll know Wednesday when I wake up.

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phoebe7439 t1_ja9ekgc wrote

The 10:1 Ratio is just not a fun model to use, the Kuchera Ratio tends to play nicer in my experience. Either way, predicting snowfall totals using solely these maps often does over-forecast for many reasons, especially the low resolution on these longer-range models you're using and the fact that not all snow that falls will stick.

​

As for what the broadcast media says, a lot of that depends on who the on-air met will be for that show, as they tend to make their own graphs and may interpret something differently or have their own model preferences, etc. The NWS will often (but not always) be more reliable since they'll have teams working on each forecast.

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TLDR: Snow is hard to forecast!

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[deleted] OP t1_ja9jwkl wrote

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phoebe7439 t1_ja9lvhw wrote

Looking into models is awesome! My one recommendation is to always compare the results afterward using a spreadsheet or something like that. Really helps show which models are biased toward certain styles of storms.

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[deleted] OP t1_ja9meb6 wrote

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Curious_Buffalo_1206 t1_jaab5lh wrote

Sounds like a nightmare to get properly labeled data… those NWS “trained spotter” reports would only go so far. Taken at different times, at inconsistent locations, tricky to account for drift and aspect.

If you know anything about the shenanigans Killington pulls with their snow stake, the flaws here would be very obvious. They report from a spot on the mountain that is not representative at all — the snow piles up there twice as deep as elsewhere. Their snow stake is a dirty liar.

Also, the best model this winter will probably be very different from the best model in an El Niño year.

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phoebe7439 t1_jaad694 wrote

ASOS comes in clutch here, when I was running the spreadsheet I only tracked the forecast and real numbers from towns with ASOS or COCORAHS stations

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[deleted] OP t1_jaadq73 wrote

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phoebe7439 t1_jaarcme wrote

I haven't seen any for snow since that's not my strong suit, but I've seen it a couple time for severe thunderstorm events up here

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phoebe7439 t1_ja9mry9 wrote

I've thought about doing that for a while, but I've lacked in my tracking of the models the last few storms unfortunately so my data is a bit further behind than I'd like

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-RYknow t1_jaai8d6 wrote

No offense, OP... but I'm just here to see if u/TheCloudBoy chimes in.

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TheCloudBoy t1_jaazgk6 wrote

See above for some of my thoughts, I remain humbled 🫡

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