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Winter storm threat disc 1/25/13-1/26/13


Allsnow

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Gorgeous look on the euro. Easily a 4-6" event for the entire area.

Accounting for ratios, especially in the NW sections of the area, it could definitely be higher than that. The warmest temperature SMQ gets to on the ECMWF while it's precipitating for this system is 19 degrees farenheit. That will give you ratios in the 15:1 to 20:1 range. Generally 0.5"-0.6" of liquid from the city west on the ECMWF.

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That must have been quite the controversial post I made regarding NOAA definitions of snowfall intensity and visibility...though they could argue it was in the wrong thread...

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Accounting for ratios, especially in the NW sections of the area, it could definitely be higher than that. The warmest temperature SMQ gets to on the ECMWF while it's precipitating for this system is 19 degrees farenheit. That will give you ratios in the 15:1 to 20:1 range. Generally 0.5"-0.6" of liquid from the city west on the ECMWF.

 

 

Wow..Jeez that is cold. Of course we will need this track and cold to hold for another 100hrs..I'd wait until we get closer until we start banking on ratios. This could easily bump north

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Accounting for ratios, especially in the NW sections of the area, it could definitely be higher than that. The warmest temperature SMQ gets to on the ECMWF while it's precipitating for this system is 19 degrees farenheit. That will give you ratios in the 15:1 to 20:1 range. Generally 0.5"-0.6" of liquid from the city west on the ECMWF.

As mentioned by others, surface temperature is only a *minor* determinant of snow ratio.  Snow growth region temperatures, lift and moisture are much more important.  The low levels are very close to isothermal, so even though temperatures at the surface are 19, at 850 its only 4 degrees colder at 15 (-9.7C) and at 700 its 14 (-10C).  Ideal snow growth is -12C to -18C.  So you won't get ideal snow ratios.  12:1 perhaps.  15:1 and higher look unlikely.

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Way suppressed on the 6z GFS. Can't win. :axe:

 

I wouldn't worry about it yet, it may have something to do with it blowing up that clipper off the coast at 84 hours which no other model really even shows the 06Z GFS seems to have major suppression biases all the time and its entire pattern from Day 5-8 on this run was way colder than most models.  There was a notable trend south tonight though, even the 06Z DGEX went south from where it had been for days.

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Those that have been really pushing for a de-amplified solution have to watch out for something like what the 06z GFS is showing. I think our best shot is a more amped up front end dump that stays snow for inland areas and changes over at the coast. Something similar to the 00z GGEM.

Why would somebody at the coast be rooting for something that causes a changeover? So they can get an inch or two of snow that gets washed away?

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Why would somebody at the coast be rooting for something that causes a changeover? So they can get an inch or two of snow that gets washed away?

The changeover would be at the very end, so everyone would still get a good amount of snow before that happened as most of the precip would be ending by then.

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The changeover would be at the very end, so everyone would still get a good amount of snow before that happened as most of the precip would be ending by then.

 

With the neutral nao you walk a fine line between too amplified and not amplified enough.

A stronger solution like yesterdays Euro would end up trending warmer in the short term.

But a weaker 0z solution would open the risk to a more suppressed solution. That's why

storms like 2-22-08 are on the rare side and these situations usually deliver more modest

snows of they end up cutting and turning to rain. So I would always want to take my chances

with a weaker system and hope it comes close enough for at least a 2-4 or 3-5 event for most.

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As mentioned by others, surface temperature is only a *minor* determinant of snow ratio.  Snow growth region temperatures, lift and moisture are much more important.  The low levels are very close to isothermal, so even though temperatures at the surface are 19, at 850 its only 4 degrees colder at 15 (-9.7C) and at 700 its 14 (-10C).  Ideal snow growth is -12C to -18C.  So you won't get ideal snow ratios.  12:1 perhaps.  15:1 and higher look unlikely.

 

I based my ratios comment from this chart from the NWS.

 

Snow growth isn't the best, but I think we can agree that what falls on the ECMWF does not have a 10:1 snow ratio.

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With the neutral nao you walk a fine line between too amplified and not amplified enough.

A stronger solution like yesterdays Euro would end up trending warmer in the short term.

But a weaker 0z solution would open the risk to a more suppressed solution. That's why

storms like 2-22-08 are on the rare side and these situations usually deliver more modest

snows of they end up cutting and turning to rain. So I would always want to take my chances

with a weaker system and hope it comes close enough for at least a 2-4 or 3-5 event for most.

Maybe I'm selfish but I can't worry about what happens at the coast. I'm well inland and if the coast changes over it doesn't effect my life. I'm not rooting for anything, that's called being a :weenie:. The point of my post was simply to say be careful what you wish for in terms of how weak or de-amplified this ends up.

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Maybe I'm selfish but I can't worry about what happens at the coast. I'm well inland and if the coast changes over it doesn't effect my life. I'm not rooting for anything, that's called being a :weenie:. The point of my post was simply to say be careful what you wish for in terms of how weak or de-amplified this ends up.

 

You are allowed to root for any solution that you want. :D But we'll see what the models are showing in a few days

once the energy gets better sampled near the West Coast.

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I based my ratios comment from this chart from the NWS.

 

Snow growth isn't the best, but I think we can agree that what falls on the ECMWF does not have a 10:1 snow ratio.

The 00z GFS bufkit data shows 10:1 ratios as far inland as KMMU

 

130125/2100Z 117  09007KT  20.6F  SNOW   16:1| 1.2|| 0.00|| 0.00|| 0.077   16:1|  1.2|| 0.00|| 0.00|| 0.08  100|  0|  0

130126/0000Z 120  06010KT  21.8F  SNOW   11:1| 2.2|| 0.00|| 0.00|| 0.195   13:1|  3.4|| 0.00|| 0.00|| 0.27  100|  0|  0

----------------------------------------------+----++-----+-------------++--------------++-------------++-----------+---+---

130126/0300Z 123  04014KT  24.2F  SNOW    7:1| 1.1|| 0.00|| 0.00|| 0.156   11:1|  4.5|| 0.00|| 0.00|| 0.43  100|  0|  0

130126/0600Z 126  02014KT  20.2F  SNOW    6:1| 0.4|| 0.00|| 0.00|| 0.062   10:1|  4.9|| 0.00|| 0.00|| 0.49  100|  0|  0

130126/0900Z 129  02011KT  18.8F  SNOW   10:1| 0.3|| 0.00|| 0.00|| 0.026   10:1|  5.2|| 0.00|| 0.00|| 0.52  100|  0|  0

130126/1200Z 132  01010KT  18.9F  SNOW   12:1| 0.3|| 0.00|| 0.00|| 0.023   10:1|  5.4|| 0.00|| 0.00|| 0.54  100|  0|  0

 

Slightly lower at KLGA

 

130125/1800Z 114  20005KT  25.8F          0:1| 0.0|| 0.00|| 0.00|| 0.000    0:1|  0.0|| 0.00|| 0.00|| 0.00    0|  0|  0

130125/2100Z 117  10007KT  22.2F  SNOW   15:1| 0.7|| 0.00|| 0.00|| 0.048   15:1|  0.7|| 0.00|| 0.00|| 0.05  100|  0|  0

130126/0000Z 120  08012KT  24.7F  SNOW    8:1| 1.1|| 0.00|| 0.00|| 0.152    9:1|  1.9|| 0.00|| 0.00|| 0.20  100|  0|  0

----------------------------------------------+----++-----+-------------++--------------++-------------++-----------+---+---

130126/0300Z 123  06016KT  27.4F  SNOW    8:1| 1.1|| 0.00|| 0.00|| 0.140    9:1|  2.9|| 0.00|| 0.00|| 0.34  100|  0|  0

130126/0600Z 126  04019KT  24.3F  SNOW    7:1| 0.5|| 0.00|| 0.00|| 0.073    8:1|  3.5|| 0.00|| 0.00|| 0.41  100|  0|  0

130126/0900Z 129  02016KT  21.5F  SNOW   10:1| 0.2|| 0.00|| 0.00|| 0.024    8:1|  3.7|| 0.00|| 0.00|| 0.44  100|  0|  0

130126/1200Z 132  01015KT  20.4F  SNOW   15:1| 0.3|| 0.00|| 0.00|| 0.020    9:1|  4.0|| 0.00|| 0.00|| 0.46  100|  0|  0

 

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The 00z GFS bufkit data shows 10:1 ratios as far inland as KMMU

 

130125/2100Z 117  09007KT  20.6F  SNOW   16:1| 1.2|| 0.00|| 0.00|| 0.077   16:1|  1.2|| 0.00|| 0.00|| 0.08  100|  0|  0

130126/0000Z 120  06010KT  21.8F  SNOW   11:1| 2.2|| 0.00|| 0.00|| 0.195   13:1|  3.4|| 0.00|| 0.00|| 0.27  100|  0|  0

----------------------------------------------+----++-----+-------------++--------------++-------------++-----------+---+---

130126/0300Z 123  04014KT  24.2F  SNOW    7:1| 1.1|| 0.00|| 0.00|| 0.156   11:1|  4.5|| 0.00|| 0.00|| 0.43  100|  0|  0

130126/0600Z 126  02014KT  20.2F  SNOW    6:1| 0.4|| 0.00|| 0.00|| 0.062   10:1|  4.9|| 0.00|| 0.00|| 0.49  100|  0|  0

130126/0900Z 129  02011KT  18.8F  SNOW   10:1| 0.3|| 0.00|| 0.00|| 0.026   10:1|  5.2|| 0.00|| 0.00|| 0.52  100|  0|  0

130126/1200Z 132  01010KT  18.9F  SNOW   12:1| 0.3|| 0.00|| 0.00|| 0.023   10:1|  5.4|| 0.00|| 0.00|| 0.54  100|  0|  0

 

Slightly lower at KLGA

 

130125/1800Z 114  20005KT  25.8F          0:1| 0.0|| 0.00|| 0.00|| 0.000    0:1|  0.0|| 0.00|| 0.00|| 0.00    0|  0|  0

130125/2100Z 117  10007KT  22.2F  SNOW   15:1| 0.7|| 0.00|| 0.00|| 0.048   15:1|  0.7|| 0.00|| 0.00|| 0.05  100|  0|  0

130126/0000Z 120  08012KT  24.7F  SNOW    8:1| 1.1|| 0.00|| 0.00|| 0.152    9:1|  1.9|| 0.00|| 0.00|| 0.20  100|  0|  0

----------------------------------------------+----++-----+-------------++--------------++-------------++-----------+---+---

130126/0300Z 123  06016KT  27.4F  SNOW    8:1| 1.1|| 0.00|| 0.00|| 0.140    9:1|  2.9|| 0.00|| 0.00|| 0.34  100|  0|  0

130126/0600Z 126  04019KT  24.3F  SNOW    7:1| 0.5|| 0.00|| 0.00|| 0.073    8:1|  3.5|| 0.00|| 0.00|| 0.41  100|  0|  0

130126/0900Z 129  02016KT  21.5F  SNOW   10:1| 0.2|| 0.00|| 0.00|| 0.024    8:1|  3.7|| 0.00|| 0.00|| 0.44  100|  0|  0

130126/1200Z 132  01015KT  20.4F  SNOW   15:1| 0.3|| 0.00|| 0.00|| 0.020    9:1|  4.0|| 0.00|| 0.00|| 0.46  100|  0|  0

 

 

I was refering to the ECMWF, which is considerably cooler than the GFS.

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