February 7th Storm Threat Discussion/Obs

[nj2va]

4 minutes ago, MillvilleWx said:

I'm thinking 8-10:1 given the mid-level frontogen involved with the wave. The s/w is still fairly prolific on guidance right now and there's going to be significant large scale ascent from the 25H jet amplifying to the north. I think one of the things the globals are not going to pick up on is that meso banding is all but a given with the current 7H progs. The 7H fronto AND 85H fronto will actually work in your favor, so you'll have deeper boundary layer lift compared to areas north and west. They have the mid-level fronto, but eastern shore will likely cash on both, which is why I like your spot, Easton, Kent Island, down to Cambridge as the local jack with central DE as another good spot pending the northern latitude push of the surface low along the coast. I'm rooting for you!

NSFW wording in this post.  I do hope CAPE jackpots too.

[Yeoman]

42 minutes ago, ovechkin said:

Serious question from a novice and my apologies in advance for my ignorance. 
I see what the models are projecting, and get there will be low dews and can calculate a wet bulb.  Yet, with temps on Saturday around 50 during the day, clouding up during the evening, and the inability in the immediate metro to cool down even to forcasted lows most nights (supposed to be 35 last night and never dropped below 40, and even last Friday night during the “very cold” stretch barely  ducked under 25,) how will this ever be cold enough to support accumulating snow?  I have seen dynaimc heavy snow accumulate at 34-35. I get it. But how can we be sure it won’t be just cloudy at 42 heading into the event in the immediate metro? Is just robust dynamic cooling? Again, sorry if this a stupid question. 

I remember calling NWS when I was 15 the day before the Feb '87 storm and asking the same question. It was in the upper 40s a few hours prior to the snow starting.

[Ravens94]

Definitely shifted 

[jayyy]

1 hour ago, BTRWx's Thanks Giving said:

Why are you showing 10:1?

Why not? A very legit meteorologist just explained 1 page back why this very well could be 8-10:1 ratios... and maybe along the Maryland coast ratios will be lower, but they could easily be 10:1 out this way. 

[WinterWxLuvr]

It’s gonna come north. Prepare yourself accordingly. 

[mappy]

Just now, WinterWxLuvr said:

It’s gonna come north. Prepare yourself accordingly. 

but the nam 

[HighStakes]

3 minutes ago, jayyy said:

Why not? A very legit meteorologist just explained 1 page back why this very well could be 8-10:1 ratios... and maybe along the Maryland coast ratios will be lower, but they could easily be 10:1 out this way. 

I only focus on northern MD and we're easily 10:1 if not 12:1 or better.

[CAPE]

24 minutes ago, MillvilleWx said:

I'm thinking 8-10:1 given the mid-level frontogen involved with the wave. The s/w is still fairly prolific on guidance right now and there's going to be significant large scale ascent from the 25H jet amplifying to the north. I think one of the things the globals are not going to pick up on is that meso banding is all but a given with the current 7H progs. The 7H fronto AND 85H fronto will actually work in your favor, so you'll have deeper boundary layer lift compared to areas north and west. They have the mid-level fronto, but eastern shore will likely cash on both, which is why I like your spot, Easton, Kent Island, down to Cambridge as the local jack with central DE as another good spot pending the northern latitude push of the surface low along the coast. I'm rooting for you!

Keep talkin' dirty. I like it.

[IronTy]

1 minute ago, HighStakes said:

I only focus on northern MD and we're easily 10:1 if not 12:1 or better.

Well the easy answer is...because that's the only fuggen choice for map selection.   

[mappy]

4 minutes ago, IronTy said:

Well the easy answer is...because that's the only fuggen choice for map selection.   

Or, you use the snow map as just another tool to forecast. ratios depend on temperature, where the dg zone is etc. snow maps shouldn't be used as a standalone thing to make forecasts.  

[Eskimo Joe]

 

[frd]

 

More amped solutions more likely per Jack,  but short of a full phase, which would not be good for points East. 

 

 

[WxUSAF]

Just now, mappy said:

Or, you use the snow map as just another tool to forecast. ratios depend on temperature, where the dg zone is etc. snow maps shouldn't be used as a standalone thing to make forecasts.  

This is definitely true. Look at temps, snow growth, etc. 

But despite all our talk, we rarely get snow ratios outside a 8-12:1 range. With the look of the soundings we’ve seen on the NAM and even GFS, I don’t see this storm being different. So unless a storm probably has substantial sleet (not the case Sunday) then the 10:1 snow maps are probably decent. 

[frd]

 

Comparison, more amped.  

 

[ErinInTheSky]

1 hour ago, chris21 said:

The snow depth map could be right, but in general I have found that product to be pretty atrocious with verification. 

Same. I have hit my Kuchera totals far more than I've hit the snow depth map totals. I'll get a 6" storm and snow depth will tell me it's 2".

Maybe like a day later that turns out to be the case from melting, but immediate measure right after the snow? Nah.

[MillvilleWx]

6 minutes ago, frd said:

 

More amped solutions more likely per Jack,  but short of a full phase, which would not be good for points East. 

 

 

This the main reason I see the jackpot region being to the west of SBY as I think some warm air intrusion within the lower boundary layer will change precip over to sleet or even rain pending rates. Highest prob for rain will be the immediate coast and points 10 miles inland. 

[Eskimo Joe]

1 minute ago, WxUSAF said:

This is definitely true. Look at temps, snow growth, etc. 

But despite all our talk, we rarely get snow ratios outside a 8-12:1 range. With the look of the soundings we’ve seen on the NAM and even GFS, I don’t see this storm being different. So unless a storm probably has substantial sleet (not the case Sunday) then the 10:1 snow maps are probably decent. 

Compare that to Maine, where they had a 56:1 event last night.

[mappy]

1 minute ago, WxUSAF said:

This is definitely true. Look at temps, snow growth, etc. 

But despite all our talk, we rarely get snow ratios outside a 8-12:1 range. With the look of the soundings we’ve seen on the NAM and even GFS, I don’t see this storm being different. So unless a storm probably has substantial sleet (not the case Sunday) then the 10:1 snow maps are probably decent. 

for sure. I wasn't trying to say that they were wrong, just that they shouldn't be take verbatim as a forecast to what any given location will received. lot more goes into forecasting snow totals than a digital snowmap  

[frd]

1 minute ago, MillvilleWx said:

This the main reason I see the jackpot region being to the west of SBY as I think some warm air intrusion within the lower boundary layer will change precip over to sleet or even rain pending rates. Highest prpb for rain will be the immediate coast and points 10 miles inland. 

You had mentioned the Eastern Shore, can you share your thoughts for Northern Delaware based on the latest data  ?  Thanks 

[IronTy]

7 minutes ago, mappy said:

Or, you use the snow map as just another tool to forecast. ratios depend on temperature, where the dg zone is etc. snow maps shouldn't be used as a standalone thing to make forecasts.  

I think you drastically overestimate my investment in forecasting.  I'm an engineer IRL, not a weatherman.  

[LP08]

Through 30, SS SW looking much healthier than 6z on the NAM.

[MillvilleWx]

3 minutes ago, frd said:

You had mentioned the Eastern Shore, can you share your thoughts for Northern Delaware based on the latest data  ?  Thanks 

Just through the night runs, I like your spot and with a bit more amplification of the s/w trough, the jack could extend up to your area. I still like a bit south of you right now as a place like Dover to Smyrna looks like they will be a great location for this one. 

[jayyy]

10 minutes ago, mappy said:

Or, you use the snow map as just another tool to forecast. ratios depend on temperature, where the dg zone is etc. snow maps shouldn't be used as a standalone thing to make forecasts.  

So.. you’re saying we shouldn’t live and die by digital snow maps?  Hehe

[stormtracker]

Looking good so far vs 6z.  S/w def more vigorous 

[mappy]

5 minutes ago, IronTy said:

I think you drastically overestimate my investment in forecasting.  I'm an engineer IRL, not a weatherman.  

okie dokie

2 minutes ago, jayyy said:

So.. you’re saying we shouldn’t live and die by digital snow maps?  Hehe

yes, thats exactly what I'm saying. 

[LP08]

Slightly better ridging out front due to the healthier SW, System crashing into the west coast is slower as well. 

[SomeguyfromTakomaPark]

Nam looks locked and loaded at 39.  A lot more juice on the western side of the storm over Tennessee. 

[frd]

Just now, DCTeacherman said:

Nam looks locked and loaded at 39.  A lot more juice on the western side of the storm over Tennessee. 

[high risk]

9 minutes ago, WxUSAF said:

This is definitely true. Look at temps, snow growth, etc. 

But despite all our talk, we rarely get snow ratios outside a 8-12:1 range. With the look of the soundings we’ve seen on the NAM and even GFS, I don’t see this storm being different. So unless a storm probably has substantial sleet (not the case Sunday) then the 10:1 snow maps are probably decent. 

       I have been one of the loudest proponents for looking at the snow depth maps, but that is because most events have a big area of sleet or mixed precip, and the 10:1 maps are horribly inflated since sleet gets tallied with snow into the snow water equivalent.     This is a setup in which I would NOT advocate the snow maps for 2 reasons     1)   this is mostly a rain or snow event with probably only a small band of sleet somewhere to our south, so 10:1 (maybe mentally lower it by 10-15% or so) map should be ok     2)  snow depth maps are underdone in events with marginal temperatures and with warm temperatures the day before which warm the top soil layer.    The land-surface model sees 33 degrees and warm soil and says "well, this is going to struggle to accumulate", not accounting for the fact that big rates can overcome those negatives.

[Ravens94]

Nam has some big time interaction this run