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Saint Patrick's Day Snow Event II


stormtracker

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CWG boom and bust might be similar but it's not the same IMO. Maybe as the event closes it looks similar but you'll never see CWG boom and bust range from .5" to 20" I don't think. Knowing the maps are based off sref etc as a base makes them more understandable tho given what it see from sref might back up the idea that they don't necessarily serve a huge purpose at least more than a day or two out.

CWG is hand drawn product geared toward the public. I like it

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I think its fine as a product and serves a purpose, even if the intended audience isn't the average citizen.  CWG essentially does the same thing with their boom and bust forecasts.  I think the product gets extra scrutiny here but in reality, very few people outside of this forum probably even see that product.

Bingo

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CWG is hand drawn product geared toward the public. I like it

I think there are similarities but CWG boom and bust are probably more like 20-30 percentile and 70-80 vs the 10/95. In theory unless there's a giant disaster the low and high end maps from LWX should never be right though I guess they'll get closer to that possibility right before an event. In this case 2" seems like an awful high bar for the least likely scenario in the city. I'm not even sure I like the boom and bust stuff.. you're either right or wrong. It's not like 1000s of people will die if you miss by 3".

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I give up

 

I give up

 

I understand what you're saying.  I also agree with Fozz that making them public is a challenge because how people run with bad ideas and FB blasts things not meant to be used for that purpose. I understand that the NWS can't really have a secret club of information, but in the end I think it makes your job harder. 

 

With that, all joking aside I think any one place will struggle to get more than 8 inches, Counties along 81 included. 

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Like we have all tried to say, it can happen...not saying it will, but it can.

Sand cools pretty easily anyway doesn't it? I'm sort of perplexed by the whole conversation. Why can 6-10 happen in coastal Calvert but not Ocean City?

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I think there are similarities but CWG boom and bust are probably more like 20-30 percentile and 70-80 vs the 10/95. In theory unless there's a giant disaster the low and high end maps from LWX should never be right though I guess they'll get closer to that possibility right before an event. I'm not even sure I like the boom and bust stuff.. you're either right or wrong. It's not like 1000s of people will die if you miss by 3".

 

as you know, I cant stand it....if you use a confidence bar there is no need for it.....CWG's map tells me this

 

We are somewhat confident that the following will happen

 

 

1" or less - 15%

1-2.5" - 30%

2.5 - 4" - 30%

4" - 8" - 25%

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The NWS maps make at least as much sense to me as the CWG maps. Both present a bewildering array of possible options and parameters that always allows at least a C+/B- forecast no matter what happens.

 

If I click point and click over Springfield Mall at I-95 and 395 , it tells me I am getting 5-11"..so a median of 8".....this is a publicly available product, telling me the best guess is 8"....I have yet to understand what products are intended for the public, which ones are to be used, and what is the "official" forecast for DC....

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I think there are similarities but CWG boom and bust are probably more like 20-30 percentile and 70-80 vs the 10/95. In theory unless there's a giant disaster the low and high end maps from LWX should never be right though I guess they'll get closer to that possibility right before an event. In this case 2" seems like an awful high bar for the least likely scenario in the city. I'm not even sure I like the boom and bust stuff.. you're either right or wrong. It's not like 1000s of people will die if you miss by 3".

Maybe they can try to narrow the confidence interval closer to the event from 90/10 to 75/25? Weather is not politics, so imo, there is more in between situations than you would think. I think 3" makes a huge difference in any storm, though less-so in 20+ events.

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Sand cools pretty easily anyway doesn't it? I'm sort of perplexed by the whole conversation. Why can 6-10 happen in coastal Calvert but not Ocean City?

 

 

it can obviously.....not that it will

 

I am a member of the public right now...What is my current forecast for where I live and where can I find it?

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From what I can tell, here's the current guidance for Towson:

 

18z NAM:  0.63"

18z GFS:  0.55"

18z RGEM:  0.47" (Estimated from metograms on meteocentre)

12z GGEM:  0.70"  (Estimated from metograms on meteocentre)

12z UKMET:  0.67"  (Estimated precip map on meteocentre)

12z Euro:  <0.3" (from reading this forum)

 

I'm pretty sure the bulk of this falls as snow for all of these.  Verbatim, the GFS has us at about -3C at 7:00 on Sunday night.

 

Ignoring the Euro for now, that would be an average of 0.6" qpf falling as snow.  At 8:1 ratios, that would be about 5".  At 10:1, that would be about 6".  Even if you assume that the Euro gives us 0" and include that in the average, we're still looking at 4-5".  So to me, some of those snow maps look a little low around here. 

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21z SREFs continue to state that DCA is slightly above freezing at 00z and ~30 by 03z MON.  850s remain same as 15z pretty much

 

Looks like a slight north nudge in QPF placement... and more area included in the 1" QPF zone

 

 

Yeah looks like the two 1" areas in CVA joined into one and bumped north a tad.

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as you know, I cant stand it....if you use a confidence bar there is no need for it.....CWG's map tells me this

We are somewhat confident that the following will happen

1" or less - 15%

1-2.5" - 30%

2.5 - 4" - 30%

4" - 8" - 25%

More and more of what we do will become probabilistic. It answers the question... What is your confidence level that we receive a certain amount or the worst case scenario? Telling folks 4-6 doesn't say much. Planners want a better way to communicate uncertainties. If there is a 5 or 10 percent chance it could be 12 then it needs to be communicated. For example... Anne Arundel OEM upgrades its snow moving equipment to heavy duty stuff at 18" that is a key threshold, at 8-12" an eoc activates requiring extra staff. If we are looking at a moderate to sig event they want to know what the probability of greater than a certain number will be...they then look at the numbers over a 48-72 hr timeframe to see what the trends are... Are they getting snowier or drier etc with time.

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Maybe they can try to narrow the confidence interval closer to the event from 90/10 to 75/25? Weather is not politics, so imo, there is more in between situations than you would think. I think 3" makes a huge difference in any storm, though less-so in 20+ events.

 

I've found that people think you bust when it is supposed to snow and they walk outside and it it is raining or it isnt snowing...if you call for an impactful storm of 5-8" and you get 3.5", the public has no idea you busted assuming the snow sticks and causes disruption

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More and more of what we do will become probabilistic. It answers the question... What is your confidence level that we receive a certain amount or the worst case scenario? Telling folks 4-6 doesn't say much. Planners want a better way to communicate uncertainties. If there is a 5 or 10 percent chance it could be 12 then it needs to be communicated. For example... Anne Arundel OEM upgrades its snow moving equipment to heavy duty stuff at 18" that is a key threshold, at 8-12" an eoc activates requiring extra staff. If we are looking at a moderate to sig event they want to know what the probability of greater than a certain number will be...they then look at the numbers over a 48-72 hr timeframe to see what the trends are... Are they getting snowier or drier etc with time.

 

I love probabilistic forecasting, even if the public doesnt love it...I do think CWG should be more deterministic on a map...they can hedge in the narrative

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I've found that people think you bust when it is supposed to snow and they walk outside and it it is raining or it isnt snowing...if you call for an impactful storm of 5-8" and you get 3.5", the public has no idea you busted assuming the snow sticks and causes disruption

unless the roadway conditions differ from their expectations

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