February the climo snow month

[weathafella]

Let’s get this in before 2/25.   Winter ends for me that date as I’m contemplating a sojourn to FL.   Probably will be contingent on both of us getting at least the first vax.  I’m ready for warmth.

[MJO812]

Jeez 2 degrees in Amarillo

Wow

[moneypitmike]

35 minutes ago, weathafella said:

Let’s get this in before 2/25.   Winter ends for me that date as I’m contemplating a sojourn to FL.   Probably will be contingent on both of us getting at least the first vax.  I’m ready for warmth.

Enjoy the mask-free living!

[weathafella]

3 minutes ago, moneypitmike said:

Enjoy the mask-free living!

Lol...we’ll mask up in public.   That’s not going away for awhile I suspect.  But more importantly we’ll be caring for relatives age 90.  But back on topic-hopefully good snow between now and  the 25th.  

[GCWarrior]

2/22 looks good on the Euro OP. Not sure if the EPS agrees. 

[NorEastermass128]

Next threats after tomorrow/Tuesday:

2/18 - Thump of SN (3-6+) to sleet/ZR to RN to dryslot.  Mild Friday?

2/22 - Miller B potential

 

[Damage In Tolland]

4 minutes ago, NorEastermass128 said:

Next threats after tomorrow/Tuesday:

2/18 - Thump of SN (3-6+) to sleet/ZR to RN to dryslot.  Mild Thursday?

2/22 - Miller B potential

 

Mild? Thursday night and Friday is the storm . It’s likely n the single digits and teens Thursday morning 

[NorEastermass128]

3 minutes ago, Damage In Tolland said:

Mild? Thursday night and Friday is the storm . It’s likely n the single digits and teens Thursday morning 

You're right.  I meant mild Friday (day after).  Maybe 40F for the coast.  Mid-upper 30s inland?

[Ginx snewx]

3 minutes ago, Damage In Tolland said:

Mild? Thursday night and Friday is the storm . It’s likely n the single digits and teens Thursday morning 

Thumper da dumpa on GFS

[Damage In Tolland]

Just now, Ginx snewx said:

Thumper da dumpa on GFS

Why doesn’t that have any snow along the water?

[Ginx snewx]

Just now, Damage In Tolland said:

Why doesn’t that have any snow along the water?

Gfs map fail 6 to 8 there

[NorEastermass128]

2 minutes ago, Ginx snewx said:

Gfs map fail 6 to 8 there

We take.  

Friday looks like a potential DSD day, for at least the coast?  

[weathafella]

6 minutes ago, NorEastermass128 said:

We take.  

Friday looks like a potential DSD day, for at least the coast?  

We’re getting into that time of year when you can have 45-50 daytime and snow developing late at night.

[NorEastermass128]

1 minute ago, weathafella said:

We’re getting into that time of year when you can have 45-50 daytime and snow developing late at night.

Yup.

[Typhoon Tip]

I've seen it be 59 in napey spring "fake warmth" spring sun at noon in early April, and mixing with snow at 6 pm that same afternoon.

[Torch Tiger]

Great look for NNE the next few weeks...like 90% of the time an active late Feb. is going to rock.

[powderfreak]

25 minutes ago, Typhoon Tip said:

I've seen it be 59 in napey spring "fake warmth" spring sun at noon in early April, and mixing with snow at 6 pm that same afternoon.

Last May we had a day up here where it was around 60F at like 11:30am and I was hiking with the dog in shorts...then had 2” of paste fall that evening while cooking dinner in an isothermal CCB.

[weathafella]

6 minutes ago, powderfreak said:

Last May we had a day up here where it was around 60F at like 11:30am and I was hiking with the dog in shorts...then had 2” of paste fall that evening while cooking dinner in an isothermal CCB.

Cooking hot dogs right?

[dendrite]

56 minutes ago, Damage In Tolland said:

Why doesn’t that have any snow along the water?

It’s snow depth change...not snowfall. What you’re seeing there is the relatively coarse grid. So it’s basically calling the snowless portion the ocean.

[Lava Rock]

Great look for NNE the next few weeks...like 90% of the time an active late Feb. is going to rock.

IDK, local met says maybe rain Friday and quieter pattern after next week. Doesn't sound rockin to me.

Sent from my Pixel 4a using Tapatalk

[powderfreak]

6 minutes ago, weathafella said:

Cooking hot dogs right?

For sure, weenies everywhere that night.  Was only supposed to snow above like 2,000ft but then 0.20”/hr water for like 3-4 hours had it flash over to heavy wet snow straight to the valley floor.  That was a textbook May dynamic cooling event last spring up this way.

[Sey-Mour Snow]

1 hour ago, Damage In Tolland said:

Why doesn’t that have any snow along the water?

Model error it’s always like that, my climo would be 0” per year lol 

[weathafella]

14 minutes ago, powderfreak said:

For sure, weenies everywhere that night.  Was only supposed to snow above like 2,000ft but then 0.20”/hr water for like 3-4 hours had it flash over to heavy wet snow straight to the valley floor.  That was a textbook May dynamic cooling event last spring up this way.

My daughter is giving me shit about how my good snowpack sucks vs Vermont.   A weenie is emerging....

[78Blizzard]

1 hour ago, Ginx snewx said:

Thumper da dumpa on GFS

Vendor model error on that map.  H700 temps above freezing during the height of the qpf, so that much actual snow is not falling in much of SNE.

[MegaMike]

49 minutes ago, Damage In Tolland said:

Why doesn’t that have any snow along the water?

That's a good question.

The algorithm takes into account "gauge losses" due to melting, compaction, etc... caused by the land-air interface. If land isn't categorized by the model at a given grid point, 0/NaN values will be produced by the algorithm. That's why there are 0/NaN values along the coastline. The (very course) GFS categorizes those grid points/locations as "water." 

The website post-processes those maps from the GFS by, snowfall(t)=abs(snow_depth(t)-snow_depth(t-1))+snowfall(t-1) - t==time.

snow_depth is calculated within the model though. For the coding/scripting weenies: https://github.com/wrf-model/WRF/blob/f311cd5e136631ebf3ebaa02b4b7be3816ed171f/phys/module_sf_noah_seaice.F [via WRF] - search for "SNOWH." I'm assuming the GFS uses the same subroutine.

For the non coding/scripting weenies: https://www.wcc.nrcs.usda.gov/ftpref/wntsc/H&H/snow/AndersonSnow17.pdf - The "new snowfall" calculation is denoted by equations 2.a though 3... It's different than what most people are accustomed to on this site. It calculates snowfall by diagnosing snow density.

[Torch Tiger]

30 minutes ago, Lava Rock said:

IDK, local met says maybe rain Friday and quieter pattern after next week. Doesn't sound rockin to me.

Sent from my Pixel 4a using Tapatalk
 

I didn't say perfect, NNE as a whole though. Looks good for many up there. Similar to when SNE has a good stretch, it may not always include S or SE areas.

[Damage In Tolland]

17 minutes ago, MegaMike said:

That's a good question.

The algorithm takes into account "gauge losses" due to melting, compaction, etc... caused by the land-air interface. If land isn't categorized by the model at a given grid point, 0/NaN values will be produced by the algorithm. That's why there are 0/NaN values along the coastline. The (very course) GFS categorizes those grid points/locations as "water." 

The website post-processes those maps from the GFS by, snowfall(t)=abs(snow_depth(t)-snow_depth(t-1))+snowfall(t-1) - t==time.

snow_depth is calculated within the model though. For the coding/scripting weenies: https://github.com/wrf-model/WRF/blob/f311cd5e136631ebf3ebaa02b4b7be3816ed171f/phys/module_sf_noah_seaice.F [via WRF] - search for "SNOWH." I'm assuming the GFS uses the same subroutine.

For the non coding/scripting weenies: https://www.wcc.nrcs.usda.gov/ftpref/wntsc/H&H/snow/AndersonSnow17.pdf - The "new snowfall" calculation is denoted by equations 2.a though 3... It's different than what most people are accustomed to on this site. It calculates snowfall by diagnosing snow density.

That’s very interesting. Is it a possibility that they are trying to show a rain /snow line in a very rudimentary fashion?

[weathafella]

29 minutes ago, 78Blizzard said:

Vendor model error on that map.  H700 temps above freezing during the height of the qpf, so that much actual snow is not falling in much of SNE.

Over 0.5 qpf occurs before H7 taints.

[ORH_wxman]

6 minutes ago, weathafella said:

Over 0.5 qpf occurs before H7 taints.

Yeah that was a pretty thumpy run on the front end. 

[MegaMike]

40 minutes ago, Damage In Tolland said:

That’s very interesting. Is it a possibility that they are trying to show a rain /snow line in a very rudimentary fashion?

No. Public websites keep snowfall calculations simple because 1) scripting Cobb's/Dube's algorithm is too computationally expensive 2) in the end, it doesn't matter which algorithm you utilize for forecasts or 3) they can't write the script.

Besides what I wrote above regarding positive snow depth, 10:1 ratios is easier to compute:

a) If they use a precipitation type algorithm (csnowsfc is boolean wrt snow-> 1==snow, 0==not snow): snowfall = csnowsfc*LWE*10. For snowfall, precipitation type algorithms perform well... Diagnosing mixed precipitation type is problematic though. Here's an article that provides results using "observed" data: https://journals.ametsoc.org/view/journals/apme/55/8/jamc-d-16-0044.1.xm. Go to Table 1.

b) If they use microphysics scheme output (SR is continuous -> from 1==all frozen precipitation to 0==no frozen precipitation): SR*LWE*10. You occasionally see websites that state, "this product may include sleet..." They likely used this methodology since SR is a function of what a microphysics scheme diagnoses (mass/concentration of rain, ice, snow, etc...). If it diagnoses graupel, sleet, and hail, SR will include graupel, sleet, and hail as well. It depends on the microphysics scheme. Most modeling systems use Thompson's microphysics schemes which means rain, ice (sleet), snow, and graupel are included in SR.

Websites should be more public about their methodologies. Some are vague as He!!. Another pet-peeve of mine, Pivotal provides Kuchera's algorithm for PAID members. Why? Nobody published a paper on its accuracy and I'm sure other SLR algorithms perform better.