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Central PA Winter 2022/2023


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3 hours ago, Itstrainingtime said:

Another reason why I don't like snow maps - there are many types of maps available, and it's easy to cherry pick (unknowingly I'm sure at times) a map that either shows a lot of snow or very little. I think all of it creates both confusion and hard feelings. Some maps include sleet, some do not. I think some are based on different ratios than others. And then, there's the positive snow depth maps, which to me at least would seem to be what matters most...when the storm ends, just how much snow is going to be on the ground...

 

Here is the 6z GFS positive snow depth map - copy paste from our neighbors to our south so it only includes the southern tier (sorry folks north of the turnpike) but for a model run that "looked" like a pure or mostly pure snow event...this looks very underwhelming: (it's a 1-4" event for us. and the storm has moved out at this point)

 

I typically don’t even bother with +snow depth maps as I don’t think they’re really meant to be applied to actual event snowfalls. It seems like those guys use them the most and it’s kind of the same mentality as saying “well it was warm the day before so the snow isn’t going to lay on anything”. The GFS has over an inch of QPF in 6 hrs in that DC-Baltimore corridor that’s mostly conditional snow. Obviously the D8-10 disclaimers aside, If that actually happened as modeled (which looked to be 2”+ hr rates for a few hours at one point), there’s absolutely no way you’d only have a plus depth change of 1-4” at the end of the event as it has for that area. 

It is a lot to consider with all the different snow maps.  I warn in here at least once or twice a season about using TT snowmaps in particular since they include sleet/ice with the 10:1 snow totaling. But each method has their flaws/limitations and it’s important to know what kind of setup you’re looking at when trying to determine the best snow map to use for a given area for an event. Do we have marginal temps aloft in the column? Abnormally cold temps? Climo (which is >10:1 in Jan/Feb in C-PA), etc, etc. For example, given the marginal nature of literally every single snowfall that has come our way this winter in our general area…I’ve been mostly paying most attention to whichever map was less out of Kuchera vs straight 10:1. Typically, the Kuchera calculates higher than 10:1 around here. But since temps (surface and aloft) have been so marginal and warmer than average climo in the snow events that have materialized in C-PA…it’s been putting out less than 10:1 in most circumstances in our region this winter.

For that D8-10 event, The 8-12”+ the straight 10:1 puts out in DC-Baltimore corridor is more of a 6-9” on the Kuchera (implying <10:1). I think that’s more than reasonable considering what the model is outputting in terms of conditional snow and temps. The 10:1 is reasonable too, really. Neither of those methods involve actual dynamics related to snow crystal growth. You can be 32ºF at the surface but if the lift is in the right spot in the snow growth zone aloft inside a death band you can still put down much greater than 10:1 ratios. Using the right snow map is definitely not a perfected science haha. 

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16 minutes ago, MAG5035 said:

I typically don’t even bother with +snow depth maps as I don’t think they’re really meant to be applied to actual event snowfalls. It seems like those guys use them the most and it’s kind of the same mentality as saying “well it was warm the day before so the snow isn’t going to lay on anything”. The GFS has over an inch of QPF in 6 hrs in that DC-Baltimore corridor that’s mostly conditional snow. Obviously the D8-10 disclaimers aside, If that actually happened as modeled (which looked to be 2”+ hr rates for a few hours at one point), there’s absolutely no way you’d only have a plus depth change of 1-4” at the end of the event as it has for that area. 

It is a lot to consider with all the different snow maps.  I warn in here at least once or twice a season about using TT snowmaps in particular since they include sleet/ice with the 10:1 snow totaling. But each method has their flaws/limitations and it’s important to know what kind of setup you’re looking at when trying to determine the best snow map to use for a given area for an event. Do we have marginal temps aloft in the column? Abnormally cold temps? Climo (which is >10:1 in Jan/Feb in C-PA), etc, etc. For example, given the marginal nature of literally every single snowfall that has come our way this winter in our general area…I’ve been mostly paying most attention to whichever map was less out of Kuchera vs straight 10:1. Typically, the Kuchera calculates higher than 10:1 around here. But since temps (surface and aloft) have been so marginal and warmer than average climo in the snow events that have materialized in C-PA…it’s been putting out less than 10:1 in most circumstances in our region this winter.

For that D8-10 event, The 8-12”+ the straight 10:1 puts out in DC-Baltimore corridor is more of a 6-9” on the Kuchera (implying <10:1). I think that’s more than reasonable considering what the model is outputting in terms of conditional snow and temps. The 10:1 is reasonable too, really. Neither of those methods involve actual dynamics related to snow crystal growth. You can be 32ºF at the surface but if the lift is in the right spot in the snow growth zone aloft inside a death band you can still put down much greater than 10:1 ratios. Using the right snow map is definitely not a perfected science haha. 

Thank you for responding. Great information and lots of learning with that. 

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Back to MAG's post and QPF numbers - the GFS and Euro agree that Mammoth CA receives between 8-10" of QPF over the next 7 days...all of course, will be snow. And, they're talking about 20-1 ratios according to the local NWS office. Mammoth Mountain now feels that with the amount of water content in their current snowpack plus what's coming over the next week, they'll be skiing into at least the middle of July if not August. (that would be without any snow after next week which is HIGHLY unlikely.)

 

The current base is 13' at Main and 20' at the summit. 

 

I'm sort of excited for my trip. Starting to wonder if we'll have travel issues heading up CA 203 into Mammoth if this keeps up. 

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2 minutes ago, Itstrainingtime said:

There is most definitely a water influence in today's temps - at 2pm, it was 77 at BWI and 61 at the Inner Harbor. Even more impressive...it was 49 at Annapolis at 2pm. 

yeah local weather guy pounding his chest saying 74 I dont buy the model low balling the numbers saying only 65. he about all but just called his own model trash but put it on tv for people to see.

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39 minutes ago, Itstrainingtime said:

Back to MAG's post and QPF numbers - the GFS and Euro agree that Mammoth CA receives between 8-10" of QPF over the next 7 days...all of course, will be snow. And, they're talking about 20-1 ratios according to the local NWS office. Mammoth Mountain now feels that with the amount of water content in their current snowpack plus what's coming over the next week, they'll be skiing into at least the middle of July if not August. (that would be without any snow after next week which is HIGHLY unlikely.)

 

The current base is 13' at Main and 20' at the summit. 

 

I'm sort of excited for my trip. Starting to wonder if we'll have travel issues heading up CA 203 into Mammoth if this keeps up. 

I still can’t over higher elevations of Los Angeles and Ventura Counties getting 2-5 FEET with isolated 7-8’ possible this weekend. What a winter in the SW US and Rockies. 

I think it was LA NWS’s first issued blizzard warning since 1989. 

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