Potential 1/17-1/18 threat

[Poimen]

[FallsLake]

Good write up from RAH:

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...

As of 237 AM Tuesday...

 

...Winter Weather Advisory all of Central North Carolina 1100 PM

tonight through 7 PM Wednesday for snow...

 

Regardless of the "milder" afternoon, a lingering, very dry

boundary layer associated with the departing arctic high pressure

will set the stage for snow after midnight in the west, spreading

late tonight and early Wednesday.

 

Moderate to high confidence in 1-3 inches of snow for much of central

NC later tonight through Wednesday.

 

Models continue to converge on a snow event for much of central North

Carolina tonight and Wednesday. A widespread 1 to 2 inches of snow is

expected, with some locally 3 inch totals over the north-central and

Northeast Piedmont and Northern Coastal Plain. This snow is fairly an

atypical snow event for our region as it will be generated by a

mid/upper system with a departing arctic high. Typically, for

accumulating snow to occur with these typically moisture starved

systems, the mid-level vorticity maximum must track just to our south

and east. This appears that it is the case this time, with the models

in good agreement. This will maximize the little moisture available

with strong lift to produce precipitation.

 

Given the dynamics and the expected evaporative cooling, it should be

a situation that brings efficient snow accumulations, even with low

QPF (0.1 to 0.3 of an inch now forecast). Snow/liquid ratios are forecast

to be 10-1 at onset, becoming 15-20 to 1 with strong cooling aloft

and at the surface as the precipitation ends Wednesday. Ground

temperatures will be cold enough too as the precipitation will start

in the west at night, and in the east by around daybreak.

 

As far as precipitation type (P-Type), the models agree in snow as

being the dominate type, with a very brief period of light rain at the

onset in the SE. Even with highs in the mid 40s to lower 50s today (the

very dry and chilly boundary layer will evaporatively cool quickly with

the onset of precipitation in the west later tonight. Partials in the

1000/850 and 850/700 strongly support this scenario. The temperatures

will quickly wet bulb to below freezing (20s).

 

The area that may get more light rain at onset is in the SE Coastal

Plain at precipitation onset Wednesday morning. This region is forecast

to have a dew point recovery to near 32, with temperatures forecast in

the mid 30s at onset (12z to 15z Wed). It may take a few hours of light

rain for the precip to transition to snow in these areas. However,

light snow is then expected as the mid level cool rapidly with the

system moving overhead (dynamic cooling).

 

The timing of snow in the west is between 100 and 400 am into the

western Piedmont, and between 400 am and 700 am in the central, and 700

am and 1000 am in the east. A window of accumulating snow should last

around 6 hours in most areas ending from west (noon or so NW) and

elsewhere mid to late afternoon.

 

Temperatures should begin warmest as the precipitation starts. So,

highs for the calendar day should end up being before the snow hits

Wednesday. Temperatures should start in the mid to upper 30s tonight

with thickening and lowering clouds. Temperatures (according to wet

bulb forecasts etc... ) should cool into the 20s during the evening.

Readings may recover a degree or two in the Yadkin Valley (far west) as

skies clear mid to late afternoon. However, the arctic air will be

pouring in on increasing NW winds, so do not expect anything more than

possibly 28 or 30 in the Triad around 300 or 400 PM, before falling

quickly again by sunset. Readings in the Triangle may not recover from

the mid 20s during the event Wed. afternoon, before falling into the

teens at night.

 

In the SE Coastal Plain Wednesday, expect any light rain to quickly

change to snow between 12 and 15z. Then snow is likely through the day,

ending by late afternoon. Highs in the upper 30s at onset, falling

quickly into the lower 30s during the day. So, an Advisory for 1-2

inches is needed all the way through the Interstate 95 corridor again.

 

Alternate scenarios include the potential for lower QPF, as these

systems are often moisture starved. The snow accumulation forecast uses

the most likely outcome when examining all available data. There is a

20-30 percent chance of lower snow totals, but 1 inch appears to be the

low end for the Triangle area, and 0.5 in the Triad, with trace to 0.1

in Fayetteville and Goldsboro. Conversely, there is a chance (20

percent) of higher totals that those officially forecast. This would be

2 to 2.5 inches in the Triad, 3-4 from the Triangle to Halifax, and 1.5

inch in Fayetteville and Goldsboro. The P-type is high confidence of

snow in all but the SE, with 70 percent chance of accumulating snow in

the SE, after some light rain to start.

 

Wednesday night... Rapidly clear skies along with the gusty NW winds

will bring wind chills into play. Actual lows should be 10- 20 NW to

SE, with wind chills zero to 10.

Thursday morning.

 

 

[ajr]

Allan seems to like the trends for central NC

 

[FallsLake]

Here's the 3K NAM snow map (10:1):

 

[Poimen]

Yeah...RDU/Triangle folks just might be among the biggest winners this time. Good for them! Good luck to all. 

Past experience says to cut these clown maps by as much as half. But a couple of points argue against that:

1. The impressive unexpected totals upstream--while not a guarantee to translate east--are a good indicator of the potential.

2. Despite the mild temps today, the ground and pavement are sufficiently cold for rapid accumulations.

3. The post-frontal nature of the precip is somewhat unique and lends itself to an upward surprise, IMO, owing to high ratios. 

We shall see. My guess is we see a general 2-3" amounts over much of the Piedmont with 3-5" amounts possible near and along the HWY 1 corridor. 

Have a great day everyone!

 

[FallsLake]

1 minute ago, lilj4425 said:

Well, that’s depressing. Lol.  

This is just one model solution. We have no idea how that initial band or the redeveloping band will act. I expect some real surprises at go time. You guys could still score.   

[Tar Heel Snow]

6z RGEM (10:1)

[Thor]

[ajr]

18 minutes ago, Tar Heel Snow said:

6z RGEM (10:1)

What a beautiful sight 24 hours out

[PackWxMan]

Someone getting 6 tomorrow.

[Brick Tamland]

Central NC looking great. That 3 to 4 inches call might be low depending on the rates

[PackGrad05]

Fishel upped the totals a little but still is wary that it will accumulate, particularly on roads.  

[FallsLake]

1 minute ago, PackGrad05 said:

Fishel upped the totals a little but still is wary that it will accumulate, particularly on roads.  

This type of setup terrifies him. Higher than normal chance of a big bust for good or bad.  

[BIG FROSTY]

Central NC looking great. That 3 to 4 inches call might be low depending on the rates

Yeah, you might be like SE Kentucky and end up with 8-12 IYBY!! ️☃️


.

[Thor]

2 minutes ago, PackGrad05 said:

Fishel upped the totals a little but still is wary that it will accumulate, particularly on roads.  

If we start as rain at all it will make travel issues substantially worse, when the brine gets washed off. 

[PackWxMan]

5 minutes ago, PackGrad05 said:

Fishel upped the totals a little but still is wary that it will accumulate, particularly on roads.  

I don't get it... soil temps are mid 30s yesterday, and it was 20 overnight. A few hours in the mid 40s isn't going to scorch the earth. It is about as cold as the ground gets around here. 

There are bigger issues than ground temps at hand. Mixing, mountains breaking it up, the band not even coming close to RDU, etc etc. Worrying about it accumulating is something my colleague would say after getting off their Apple Weather app.

[PackGrad05]

Yea

Just now, FallsLake said:

This type of setup terrifies him. Higher than normal chance of a big bust for good or bad.  

He just said that he is confident we will see at least an inch fall, but not sure it will accumulate, particularly on roads.  Says when you've been around for 36 years and seen all the things that can go wrong, you remember it.  I respect that.  

[kvegas-wx]

I'm 7° under forecast overnight.  I highly doubt the triad sees 45 today and the ground is solid as a rock.  My driveway even heaved up again.  Its going to accumulate, whatever falls.

[Hammer]

If we start as rain at all it will make travel issues substantially worse, when the brine gets washed off. 

I have the same concern here in Cherokee County GA. Rain will wash off brine, then freeze, then snow (if we are lucky), then below 32 for 24 to 36 hours.
Could be a mess.


. Pro

[PGAWx]

27 minutes ago, PackGrad05 said:

Yea

He just said that he is confident we will see at least an inch fall, but not sure it will accumulate, particularly on roads.  Says when you've been around for 36 years and seen all the things that can go wrong, you remember it.  I respect that.  

What setup doesn't seem to terrify him?  Every storm you hear some type of excuse from him and that whole team.  

[wxdawg10]

28 minutes ago, PackGrad05 said:

Yea

He just said that he is confident we will see at least an inch fall, but not sure it will accumulate, particularly on roads.  Says when you've been around for 36 years and seen all the things that can go wrong, you remember it.  I respect that.  

the mental damage NC winters have done to him..Words of a truly broken man.

[FallsLake]

6 minutes ago, kvegas-wx said:

I'm 7° under forecast overnight.  I highly doubt the triad sees 45 today and the ground is solid as a rock.  My driveway even heaved up again.  Its going to accumulate, whatever falls.

Sure will. RAH says the temps will quickly fall once the snow starts. I'm interested in the potential rates > 10:1. RAH threw out 15-20:1 possibilities. That would make things very interesting.   

[Summey]

2 minutes ago, wxdawg10 said:

the mental damage NC winters have done to him..Words of a truly broken man.

I don’t get the hate for fishel by some here.  He is a darn good met and is correct most of the time.  No art, craft or science is 100%.

 

i feel fortunate to have him.

[BullCityWx]

13 minutes ago, kvegas-wx said:

I'm 7° under forecast overnight.  I highly doubt the triad sees 45 today and the ground is solid as a rock.  My driveway even heaved up again.  Its going to accumulate, whatever falls.

Noted the same thing headed out today. Ground is back to hard as a brickz

[mackerel_sky]

Just now, Queencitywx said:

Noted the same thing headed out today. Ground is back to hard as a brickz

There is nothing harder!

[WakeCountyWX]

 

[frazdaddy]

8 minutes ago, wxdawg10 said:

the mental damage NC winters have done to him..Words of a truly broken man.

The man wrote the curriculum and exam for the national AMS certification for on air mets. The expert on NC weather bar none.

[tramadoc]

AKQ has lowered expectations the farther east you go. Western areas of their CWA are under a WWA, eastern areas just have a brief mention of snow in their HWO.

 

 

[FallsLake]

1 minute ago, Summey said:

I don’t get the hate for fishel by some here.  He is a darn good met and is correct most of the time.  No art, craft or science is 100%.

 

i feel fortunate to have him.

I think he's one of the best. But, I don't watch him or other on air mets because they're too conservative and simplistic. Don't get me wrong, I understand that they have to cater to the general public. So really my problem is I know more than the general public and because of this I don't watch TV/cable mets. This site and the NWS is it.     

[wake4est]

Allan updated