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Dec 9-10 storm threat


ORH_wxman

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Well when trying to figure out snow amounts there are two things that are important...precip (caused by lift) and temperatures. So it's important to figure out what falls and when to determine snow and mix/rain amounts. If the NAM shunts the better forcing eastward and occluded to cut off the inflow, then there's a difference between 4-6" of snow then sleet/rain, and 10-12" snow then sleet and rain.

What am I missing? This isn't debbie or anything, it's merely an observation between two model runs that apparently annoys some haha.

QPF is always underestimated on the nw periphery because it is dictated more by mid level proccesses....that is what you have missed, and continue to miss. 

After seeing that the storm is the only thing that you did not miss the day before tday, I would have thought that you would have learned.

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QPF is always underestimated on the nw periphery because it is dictated more by mid level proccesses....that is what you have missed, and continue to miss.

After seeing that the storm is the only thing that you did not miss the day before tday, I would have thought that you would have learned.

Haha you do realize the model QPF in that storm was correct right? We just got big ratios (0.5" QPF for 11"), which also happens on the NW side. Dendrite got 3 times the QPF we did which was what was progged. You are confusing QPF with snow amounts.

Do you know for sure the lift and moisture is *always* under-estimated on the NW side? I think it's more that we often miss the snow growth potential in those scenarios, not the actual moisture that falls. Like that event back in January last year when Scooter got 18" of dandruff. That NW side wasn't necessarily under modeled QPF wise, it's just the big ratios help.

I think this system is being under done in upstate NY, that's the real NW deform zone in this storm.

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Haha you do realize the model QPF in that storm was correct right? We just got big ratios (0.5" QPF for 11"), which also happens on the NW side. Dendrite got 3 times the QPF we did which was what was progged. You are confusing QPF with snow amounts.

Do you know for sure the lift and moisture is *always* under-estimated on the NW side? I think it's more that we often miss the snow growth potential in those scenarios, not the actual moisture that falls. Like that event back in January last year when Scooter got 18" of dandruff. That NW side wasn't necessarily under modeled QPF wise, it's just the big ratios help.

I think this system is being under done in upstate NY, that's the real NW deform zone in this storm.

 Yes, true.

I guess I just took a cursory glance while working and saw QPF quibbling from a snow recipient, while most of us see mainly rain.

Guilty.

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 Yes, true.

I guess I just ttok a cursory glance while working and saw QPF quibbling from a snow recipient, while most of us see mainly rain.

Guilty.

 

It is also the NAM....it was just an observation, didn't want to start anything.  For me and a forecast stand point, what happens in those 6-9 hours prior to the change-over is critical in determining final snow amounts.  Its going to snow, I think worst case scenario is 3-4" before sleet/zr...so I'm not down on this at all.  It'll be a net gain.  Its just impact-wise there's a big difference between 4" and 12", which will essentially all be determined by how hard it rips tomorrow evening.  Unfortunately I'm usually in the spot that some in SNE are in during certain storms...crucial to how much moisture falls prior to changeover time (say 6z)...where as NNY and Watertown/ART is where I usually am when eastern SNE is mixing.  They keep that deeper cold and should have much better ratios, I think snow amounts will be under-forecasted out that way.

 

The NAM sort of cut off the moisture feed by the time that band lifted up this far north, which was a big change from earlier runs, that's all I was noting.  Not just whining that it cut my QPF...though I see how it comes off that way.  My apologies.

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It is also the NAM....it was just an observation, didn't want to start anything.  For me and a forecast stand point, what happens in those 6-9 hours prior to the change-over is critical in determining final snow amounts.  Its going to snow, I think worst case scenario is 3-4" before sleet/zr...so I'm not down on this at all.  It'll be a net gain.  Its just impact-wise there's a big difference between 4" and 12", which will essentially all be determined by how hard it rips tomorrow evening.

 

The NAM sort of cut off the moisture feed by the time that band lifted up this far north, which was a big change from earlier runs, that's all I was noting.  Not just whining that it cut my QPF...though I see how it comes off that way.  My apologies.

Nah, its good. 

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NAM definitely somewhat less juiced this run, but its the NAM ...and the next run could be wet as hell again. :)

 

It is also the NAM....it was just an observation, didn't want to start anything.  For me and a forecast stand point, what happens in those 6-9 hours prior to the change-over is critical in determining final snow amounts.  Its going to snow, I think worst case scenario is 3-4" before sleet/zr...so I'm not down on this at all.  It'll be a net gain.  Its just impact-wise there's a big difference between 4" and 12", which will essentially all be determined by how hard it rips tomorrow evening.  Unfortunately I'm usually in the spot that some in SNE are in during certain storms...crucial to how much moisture falls prior to changeover time (say 6z)...where as NNY and Watertown/ART is where I usually am when eastern SNE is mixing.  They keep that deeper cold and should have much better ratios, I think snow amounts will be under-forecasted out that way.

 

The NAM sort of cut off the moisture feed by the time that band lifted up this far north, which was a big change from earlier runs, that's all I was noting.  Not just whining that it cut my QPF...though I see how it comes off that way.  My apologies.

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ugh,watch your heart rate

 

Got that right!  Scoop a little, rest a little.

When we got the 24" dump atop 27" snowpack in Feb. 2009 (we were then without powered snow removal capacity), it took my son and I 6 hours to clear the driveway, and he's back in Japan so unlikely to be of assistance.  (He also never caught on to the necessity, when using the scoop, of piling snow so as to leave room to put the next snowfall.)

 

Haha yeah theNAM p-type maps have it snowing in CT while it's raining steadily all over NNE later on in the storm.

 

Are they channeling the 2nd round of late Feb 2010?

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