Wintry 1/7/17-1/10/17 Winter Storm

[Shawn]

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I approve that. Definitely blending that with the CMC and GFS snowfall output.

 

[Shawn]

We shall see. But south of I-20 I think we are setting up for a cold ass rain.

Including the airport. I live in South Fulton County. I think it will trend colder!

 

[Shawn]

Well Chris, CAE seem to be on board with the colder GFS.  Here is something they had in their discussion that may be of interest for you:

The surface low will cross the northern Florida peninsula and
eject out into the Atlantic Friday night as a modified Arctic air
mass spreads southeast across the area. Have raised PoPs in the
forecast into the high chance or likely category Friday night into
Saturday morning. There remains some uncertainty with respect to
how quickly the cold air will advect in and how much precipitation
will be in place as it does so, but model consensus supports a
winter weather event across the area. While there could be some
mixed precipitation Friday night, prefer to leave any mention of
ice out of the forecast and just indicate rain mixing with and
eventually changing over to snow from the northwest later Friday
night into Saturday morning. Most of the area should experience
snow Saturday morning, but have kept a rain/snow mix in for the
eastern Midlands and lower CSRA in case the low tracks closer to
the coast. MOS temperatures appear too warm on Saturday, as raw
model output and soundings support considerably cooler
temperatures. For now we show highs in the mid and upper 30s
Saturday, but it`s very possible temperatures will remain nearly
steady or fall below freezing through the day. While there is the
potential for accumulating snowfall, it`s still too early to
determine amounts. However, impacts to travel are possible across
the area. The precipitation ends rather quickly Saturday
afternoon as the low pulls away to the northeast.

 

[Shawn]

Lets all round up a bus and go to Brick's house.

 

[Shawn]

Well Chris, CAE seem to be on board with the colder GFS.  Here is something they had in their discussion that may be of interest for you:

The surface low will cross the northern Florida peninsula and
eject out into the Atlantic Friday night as a modified Arctic air
mass spreads southeast across the area. Have raised PoPs in the
forecast into the high chance or likely category Friday night into
Saturday morning. There remains some uncertainty with respect to
how quickly the cold air will advect in and how much precipitation
will be in place as it does so, but model consensus supports a
winter weather event across the area. While there could be some
mixed precipitation Friday night, prefer to leave any mention of
ice out of the forecast and just indicate rain mixing with and
eventually changing over to snow from the northwest later Friday
night into Saturday morning. Most of the area should experience
snow Saturday morning, but have kept a rain/snow mix in for the
eastern Midlands and lower CSRA in case the low tracks closer to
the coast. MOS temperatures appear too warm on Saturday, as raw
model output and soundings support considerably cooler
temperatures. For now we show highs in the mid and upper 30s
Saturday, but it`s very possible temperatures will remain nearly
steady or fall below freezing through the day. While there is the
potential for accumulating snowfall, it`s still too early to
determine amounts. However, impacts to travel are possible across
the area. The precipitation ends rather quickly Saturday
afternoon as the low pulls away to the northeast.

I agree!

 

[Shawn]

Lets all round up a bus and go to Brick's house.

I agree...

 

[Shawn]

So, looking over the 0z Euro snowfall output, I agree with the snowfall amounts north of ATL. This is when the blend of GFS comes into play, I still think that there will be a narrow heavy band setting up through ATL, central SC and up to eastern NC. The reason why I think this is because the track of low and with the circulation, this brings that heavier moisture over those areas. This could occur soon as the low is off of the SE coast. (These areas do get the SW flow at first with GOM interaction)

 

[Shawn]

Dang it! Why doesn't Tropical Tidbits have precip data for the Euro? 850 temps are looking good for CHA on the Euro. Can someone tell me if it's bringing us some precip love this far north?

It costs a fortune to license the data. like, quarter million type numbers.

Oh yeah, I'm sure based on the price of subscriptions. They have most of the other Euro data, though. Just not the precip...

If I am not mistaken that data you see is free.  Notice you don't have 500mb Vorticity and things like that which are very important.  I think they call it "WMO ESSENTIAL" or something like that anyone can access and generate maps from.

Yep, They've got most of the lower dynamics, but are missing a lot of upper dynamics and thermodynamics (like 2m temps). Seems like the cheapest subscriptions I can find are a couple hundred a year. I have enough expensive hobbies already that I think I would have a tough time selling that one to the wife... ;-)

 

[Shawn]

We shall see. But south of I-20 I think we are setting up for a cold ass rain.

Was it a cold rain on the 12z also?

 

[Shawn]

Well Chris, CAE seem to be on board with the colder GFS.  Here is something they had in their discussion that may be of interest for you:

The surface low will cross the northern Florida peninsula and
eject out into the Atlantic Friday night as a modified Arctic air
mass spreads southeast across the area. Have raised PoPs in the
forecast into the high chance or likely category Friday night into
Saturday morning. There remains some uncertainty with respect to
how quickly the cold air will advect in and how much precipitation
will be in place as it does so, but model consensus supports a
winter weather event across the area. While there could be some
mixed precipitation Friday night, prefer to leave any mention of
ice out of the forecast and just indicate rain mixing with and
eventually changing over to snow from the northwest later Friday
night into Saturday morning. Most of the area should experience
snow Saturday morning, but have kept a rain/snow mix in for the
eastern Midlands and lower CSRA in case the low tracks closer to
the coast. MOS temperatures appear too warm on Saturday, as raw
model output and soundings support considerably cooler
temperatures. For now we show highs in the mid and upper 30s
Saturday, but it`s very possible temperatures will remain nearly
steady or fall below freezing through the day. While there is the
potential for accumulating snowfall, it`s still too early to
determine amounts. However, impacts to travel are possible across
the area. The precipitation ends rather quickly Saturday
afternoon as the low pulls away to the northeast.

I agree with that. I think the euro is too warm. I think it will be colder. We.need that high to build.asap

 

[Shawn]

We shall see. But south of I-20 I think we are setting up for a cold ass rain.

Was it a cold rain on the 12z also?

Euro yes gfs and cmc no

 

[Shawn]

Would someone who has access to wxbell mind posting the zoomed in ECMWF snow map with counties? Would like to see where exactly the gradient sets up in NC. Thanks!

 

[Shawn]

So, looking over the 0z Euro snowfall output, I agree with the snowfall amounts north of ATL. This is when the blend of GFS comes into play, I still think that there will be a narrow heavy band setting up through ATL, central SC and up to eastern NC. The reason why I think this is because the track of low and with the circulation, this brings that heavier moisture over those areas. This could occur soon as the low is off of the SE coast. (These areas do get the SW flow)

 
What are you thinking for AL?

 

[Shawn]

Well...I will see what EPS says...

 

[Shawn]

Dang it! Why doesn't Tropical Tidbits have precip data for the Euro? 850 temps are looking good for CHA on the Euro. Can someone tell me if it's bringing us some precip love this far north?

It costs a fortune to license the data. like, quarter million type numbers.

Oh yeah, I'm sure based on the price of subscriptions. They have most of the other Euro data, though. Just not the precip...

If I am not mistaken that data you see is free.  Notice you don't have 500mb Vorticity and things like that which are very important.  I think they call it "WMO ESSENTIAL" or something like that anyone can access and generate maps from.

Yep, They've got most of the lower dynamics, but are missing a lot of upper dynamics and thermodynamics (like 2m temps). Seems like the cheapest subscriptions I can find are a couple hundred a year. I have enough expensive hobbies already that I think I would have a tough time selling that one to the wife... ;-)

I have never used it, but check out this: $10 a month with discounts.  I think they offer a trial - http://www.eurowx.com/

 

[Shawn]

Keep in mind colder air aloft will get drug down as well during heavier precipitation...or is that incorrect?


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[Shawn]

Dang it! Why doesn't Tropical Tidbits have precip data for the Euro? 850 temps are looking good for CHA on the Euro. Can someone tell me if it's bringing us some precip love this far north?

If you don't mind it delayed you can get EURO snowfall totals, msl, 2m temps, free on WeatherUnderGround. Just go to the interactive radar and play with their settings on the right under Model Center. Good for those who wanna sleep and check later.

 

[Shawn]

This discussion will focus on the potential wintry precipitation
late Friday and Saturday. A majority of the previous forecast
discussion remains valid.

The models have been trending closer together the past 24 to 48
hours, but some newer data is interesting. Generally speaking, the
model suite is fairly agreeable with the positive tilt trough
dropping into the Mississippi Valley and then into the Tennessee
Valley by Saturday. Only fairly minor timing and height
differences noted. Zonal flow noted ahead of this feature. The
models have a trend of flip flopping in the 4-6 day time frame
before becoming more in line. The latest ECMWF has just trended
back to closer to previous solutions that were warmer. The
GFS/GEFS have continued the trend of plenty of cold air all the
way to Montgomery. Models tend to have difficulty with the colder
airmasses and the extent of the penetration southward. The
thermodynamic parameters amongst the models do not match up but
will have to intensely watch these developments.

At this time, will introduce graphics that indicate the potential
of accumulating wintry precipitation for areas north of a line
from Demopolis to Alexander City. It is a bit too early to
establish specific precipitation types and amounts, but all types
look possible at this point. We will start narrowing the focus by
Wednesday if these trends continue. Stay tuned, there will be
adjustments on this developing dynamic situation.

 

[Shawn]

That's from bham 2354 update.

 

[Shawn]

It costs a fortune to license the data. like, quarter million type numbers.

Oh yeah, I'm sure based on the price of subscriptions. They have most of the other Euro data, though. Just not the precip...

If I am not mistaken that data you see is free.  Notice you don't have 500mb Vorticity and things like that which are very important.  I think they call it "WMO ESSENTIAL" or something like that anyone can access and generate maps from.

Yep, They've got most of the lower dynamics, but are missing a lot of upper dynamics and thermodynamics (like 2m temps). Seems like the cheapest subscriptions I can find are a couple hundred a year. I have enough expensive hobbies already that I think I would have a tough time selling that one to the wife... ;-)

I have never used it, but check out this: $10 a month with discounts.  I think they offer a trial - http://www.eurowx.com/

Thanks! I'll check that out! Btw, this forum is amazing! I really appreciate the work you guys have put into this. I freaked out a little bit when I went to Talk Weather one day and it wasn't there anymore.