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Central PA Winter 23/24


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Give me an inch of precip like the 18z Euro shows & I like the Harrisburg area’s chances to score Warning level snow with this low track & cold enough air in place.
If the precip stays moderate to heavy, it should stay mostly snow in my opinion based on my experiences over the years.

IMG_4082.png

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7 minutes ago, canderson said:

Dumb question: what exactly is the snow depth map the gfs produced? Is that snow after a storm? How is that even measured? 

Probably some kind of computer algorithm that takes temp, dp, compaction, and who knows what else into consideration. 

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11 minutes ago, canderson said:

Dumb question: what exactly is the snow depth map the gfs produced? Is that snow after a storm? How is that even measured? 

It is the actual snow that will remain after a storm. So we get 6" accums but compaction and temps above freezing/rain take a toll, it is what you see on the ground when the sun comes out. Many Mets use it vs. The accum maps.  Computer magic.

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1 minute ago, Bubbler86 said:

It is the actual snow that will remain after a storm. So we get 6" accums but compaction and temps above freezing/rain take a toll, it is what you see on the ground when the sun comes out. Many Mets use it vs. The accum maps.  Computer magic.

Basically voodoo

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Also, the snow depth change maps on the GFS are not related to anything after the storm    So, if it says 2" on Sunday it is still 2" on Wed after the Ark flooding coming our way.   It is cumulative.   So, to me it is only useful for the hours after a snow event.   Here is the actual snow depth map for a week out.  Not cumulative.   Brown town and maybe Walmart parking lots. 

image.thumb.png.962a936257bda9900a7aa23eb9efe020.png

 

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9 minutes ago, Superstorm said:


Did not know that was a rule. Actually, did not know when they stop being useful.


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LOL it is not a rule, I was kidding and did not mean to offend.  But most will move away from them because you have 20, 30 models being fed purposely alternate (one could argue false)  data so close to an event, at what point do you assume the real data will prevail.  A lot of forecasting outfits will not refer to them within 3-5 days of an event.   When you have such a small spread of 72 or 96 hours, usually the purposely entered alterations do not produce as much effect as say 6-7 days out. 

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LOL it is not a rule, I was kidding and did not mean to offend.  But most will move away from them because you have 20, 30 models being fed purposely alternate (one could argue false)  data so close to an event, at what point do you assume the real data will prevail.  A lot of forecasting outfits will not refer to them within 3-5 days of an event.   When you have such a small spread of 72 or 96 hours, usually the purposely alterations do not produce as much effect as say 6-7 days out. 

It’s all good. No offense taken.

Good information to know.


.
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23 minutes ago, Superstorm said:

I assume EPS numbers are going up as we get closer in time to the event?


.

Indeed… the 18z EPS is locked in!

Amounts went increased a bit for Harrisburg, York & even good old Rouzerville (even though he hates ensembles…lol)

 

1 minute ago, mitchnick said:

Dang Eps!

sn10_acc-mean-imp.us_state_pa (20).png

 

IMG_4085.png

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4 minutes ago, Blizzard of 93 said:

Indeed… the 18z EPS is locked in!

Amounts went increased a bit for Harrisburg, York & even good old Rouzerville (even though he hates ensembles…lol)

 

 

IMG_4085.png

I don't hate them but do not think much of their use for snow maps at any range much less 18 hours before the event starts.  

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