December 8-10, 2018 Winter Storm

[CentralNC]

1 minute ago, Queencitywx said:

I really doubt this storm ends up as 100% snow for anyone except the mountains, including the foothills. The ratio of sleet to snow obviously grows as you push further east but the question is how much sleet. I do feel pretty confident right now that it's either going to be sleet or snow at this juncture IMBY. 

Agree 100%

[sarcean]

1 minute ago, Queencitywx said:

I really doubt this storm ends up as 100% snow for anyone except the mountains, including the foothills. The ratio of sleet to snow obviously grows as you push further east but the question is how much sleet. I do feel pretty confident right now that it's either going to be sleet or snow at this juncture IMBY. 

There is so much QPF that there doesn't need to be all snow to be a great storm.  With nearly 2" of liquid...even if it is a 6:1 or 8:1 ratio for a decent portion of the event, it will still be significant.

[PackGrad05]

Just now, sarcean said:

There is so much QPF that there doesn't need to be all snow to be a great storm.  With nearly 2" of liquid...even if it is a 6:1 or 8:1 ratio for a decent portion of the event, it will still be significant.

True, but I could see some snow and then changeover to rain that washes it all away.  

[lilj4425]

5 minutes ago, PackGrad05 said:

True, but I could see some snow and then changeover to rain that washes it all away.  

Why must you ruin my day like that? Dang warm noses. 

[griteater]

9 minutes ago, Queencitywx said:

I really doubt this storm ends up as 100% snow for anyone except the mountains, including the foothills. The ratio of sleet to snow obviously grows as you push further east but the question is how much sleet. I do feel pretty confident right now that it's either going to be sleet or snow at this juncture IMBY. 

That's the takeaway when viewing the ensemble member and ensemble mean snow totals.  On one hand they are bad because they give the impression of total snowfall in areas with mixed precipitation, but on the other hand, if the members/mean are increasing they do give you an idea that the model is trending toward more wintry precipitation, it just may not be snowfall.

[BullCityWx]

7 minutes ago, sarcean said:

There is so much QPF that there doesn't need to be all snow to be a great storm.  With nearly 2" of liquid...even if it is a 6:1 or 8:1 ratio for a decent portion of the event, it will still be significant.

Yep, this too. This isnt one of these la nina storms where we struggle for QPF. This thing is juiced up. 

[mackerel_sky]

38 minutes ago, UpstateSCGamecock said:

 

GSP?


.

 

Think I saw 12-14”!!

[BullCityWx]

1 minute ago, griteater said:

That's the takeaway when viewing the ensemble member and ensemble mean snow totals.  On one hand they are bad because they give the impression of total snowfall in areas with mixed precipitation, but on the other hand, if the members/mean are increasing they do give you an idea that the model is trending toward more wintry precipitation, it just may not be snowfall.

and I should've probably mentioned that when I was talking about the ensembles. If it's 2" of QPF, I could easily see it being 6" of snow and 3" of sleet. It could always change to rain but I cant see the surface warming that much with north winds for the duration.

[Buddy1987]

What strikes me the most this morning as I’ve finally been able to go through the panels, along with the pages on the board here is the NAM’s low level cold compared to the other models. The dew point difference is night and day between it and the gfs. Obv if some of the folks on here are not aware, the NAM’s superiority is by far #1 when tracking events such as these. It’s low level resolution allows it to sniff cad out. If I were a betting man, regardless of where the low moves in its final stages, that cad is going to be a cold dome and extremely hard to dislodge. As we get closer, it will be interesting to say the least on what effect the banana high and/or HP up in northern New England have on us. Stay tuned!

[kvegas-wx]

I see today is the day that begins a new stage of grief as we are now moving from "bargaining" to "depression" once the reality begins to set in.  Happens every storm without fail.  Don't worry, "acceptance" of your fate is a mere 72 hours away!  (accept for Mack, he's already moved on to his first January storm) 

[ajr]

4 minutes ago, griteater said:

That's the takeaway when viewing the ensemble member and ensemble mean snow totals.  On one hand they are bad because they give the impression of total snowfall in areas with mixed precipitation, but on the other hand, if the members/mean are increasing they do give you an idea that the model is trending toward more wintry precipitation, it just may not be snowfall.

To support this idea, this is exactly what is showing in p-type breakdowns on the GEFS - while still a mixed bag, the 6z has higher prob of snow (30-40% vs 20-30%)

[griteater]

The 06z EPS Mean update: as the storm moves thru the gulf, it bumped a little south from the previous run, but then bumped a little north (northwest) as the low moves off the SE coast.  Over the last 3 runs, it has trended stronger with this critical shortwave that rolls thru the Great Lakes on Friday to reinforce the confluence over the northeast to keep our storm from climbing way north.  The snow map matches fairly well with the 00z run (note: the off hour runs end at hr144, so there is a bit more snow to come on the snow map, especially to the north / northeast).

 

[gman]

13 minutes ago, PackGrad05 said:

True, but I could see some snow and then changeover to rain that washes it all away.  

It’s Dec. 4th. I’ll take that scenario right now! 

[Orangeburgwx]

http://www.emc.ncep.noaa.gov/gc_wmb/tdorian/gefs/EMCGEFSplumes.html

 

@mackerel_sky GSP

[NavarreDon]

Here is some thoughts from the MOB office on where they currently think the surface low is headed thru their FA. This will pertain more to the Upstate SC & WNC crew. It might be worth the read for you guys up north. Down here I have to wonder if we will ever dry out!

LONG TERM /Friday Through Monday/...Another mild day expected
Friday with daytime high temperatures climbing into upper 50s to
lower 60s...within a few degrees of seasonal norms. Easterly
surface winds will gradually strengthen during the afternoon and
become southeasterly in response to an approaching low pressure
system to our west. By Saturday night, an eastward propagating
cold front is projected over the Western Gulf with a surface low
just offshore of the Southwest Louisiana and Texas border with a
warm front extending eastward across the Northern Gulf. There
still remains a lot of variability between the models on the
evolution of this system as well as its timing. Have trended this
forecast package more towards the GFS and UKMET solutions of
keeping the surface low and attendant warm front generally along
the coast as if moves east, but did address the potential for more
convection inland with increased PoPs and isolated thunderstorms
due to the more northerly track advertised by the ECMWF, GEM and
some of the GFS ensemble members. It currently looks like the best
chance of precipitation will occur Saturday afternoon through
Saturday night with rainfall amounts heaviest closer to the coast
where forcing for ascent will be strongest and precipitable water
amounts will approach two inches. Rainfall amounts of 2 to 4
inches appear possible at this time along the coast tapering off
to 1 to 2 inches inland. Indications are this system will be
relatively fast moving so not anticipating widespread flooding but
localized flooding will remain possible. Another critical concern
is whether or not the warm sector shifts inland if it does, this
could lead to strong to possibly severe thunderstorms especially
along the coastal counties of Alabama and the Western Florida
Panhandle. We will continue to monitor trends and adjust
accordingly. For now, continued with the previous thinking of the
surface low moving east along the coast with most of the surface
based instability remaining offshore.

[Steven_1974]

29 minutes ago, Queencitywx said:

I really doubt this storm ends up as 100% snow for anyone except the mountains, including the foothills. The ratio of sleet to snow obviously grows as you push further east but the question is how much sleet. I do feel pretty confident right now that it's either going to be sleet or snow at this juncture IMBY. If I was s&e of 85(Cary, Raleigh, Most of Wake and Johnston), I'd be really concerned about a massive ice storm. I also feel like we're going to see a colder surface reflection with the damming and heavy precip. 

If the choice is between ice storm and a cold rain here in Cary, I'll just go ahead and take the cold rain. Last thing anyone needs.

[CADEffect]

I really need to read up more on plumes and their accuracy. 

The GEFS plumes paints about a 5in snow storm around KGSP. I still need to do research, but ensembles and plumes are painting a different story then the operation models are suggesting. 

I am assuming that is why it’s important not to just go by the GFS or the EURO or any OP model alone, but use its members and ensembles.

 

[Iceagewhereartthou]

1 hour ago, jjwxman said:

I agree 100%.  The dewpoint on the NAM at 84 is 10-20 degrees cooler than the GFS.  Now we all know the NAM past 48 hours can be a crap shoot, but these numbers are probably not all that off.

 

This matches up almost exactly like the snowfall output maps we're seeing from the GFS and Euro right now. This map doesn't bring the lower DP s into the upstate or SC, and the snowfall maps (op clown maps, not ensemble means) are almost an exact match, with any real accums stopping at the boarder. Remember, in the SE (especially outside elevation) cold is ALWAYS the first consideration. Needs these dews in the teens to come further south and west for any real chance for most.

[Sw NC weather]

The 12 nam at 84 hr is quite a bit colder then the 6z gfs at hr 90

[eyewall]

I am growing more confident that this will be a bust for us RDU folks unless you like cold rain and perhaps a touch of sleet/zr. At best we could get lucky with a few backside flakes with the dreaded cold air chase. It is close but I am just not seeing the amount of cold air that makes me confident in a seeing a memorable winter storm. On a side note, the northern NC counties should keep an eye for a few flakes in the very early hours of Wed morning.  

[jjwxman]

7 minutes ago, Iceagewhereartthou said:

This matches up almost exactly like the snowfall output maps we're seeing from the GFS and Euro right now. This map doesn't bring the lower DP s into the upstate or SC, and the snowfall maps (op clown maps, not ensemble means) are almost an exact match, with any real accums stopping at the boarder. Remember, in the SE (especially outside elevation) cold is ALWAYS the first consideration. Needs these dews in the teens to come further south and west for any real chance for most.

Like this?  12z NAM:

[griteater]

12z NAM Surface Wet Bulb Temps on Friday - the white line is 32 deg

[rduwx]

3 minutes ago, eyewall said:

I am growing more confident that this will be a bust for us RDU folks unless you like cold rain and perhaps a touch of sleet/zr. At best we could get lucky with a few backside flakes with the dreaded cold air chase. It is close but I am just not seeing the amount of cold air that makes me confident in a seeing a memorable winter storm. On a side note, the northern NC counties should keep an eye for a few flakes in the very early hours of Wed morning.  

I'm in agreement eyewall.  Great looking system but I believe the cold will be lacking for us.  The further west of Raleigh you go the better imo.  Hopefully things will change in the modeling today that will make me change my mind.

[BullCityWx]

I apologize if I missed this being mentioned but the UKMET had a significant snowfall increase on its clown maps at 0z. 

[WarmNose]

4 minutes ago, jjwxman said:

Like this?  12z NAM:

Wow. South VA dp’s in the low teens..looks good to me 

[WinstonSalemArlington]

Keep in mind, Durham and Chapel Hill/Hillsborough often do quite well with snowfall while Raleigh is blanked.  It's happened a lot in these setups.

[Buddy1987]

3 minutes ago, WarmNose said:

Wow. South VA dp’s in the low teens..looks good to me 

Ratios for the win!

[ryan1234]

It baffles me that people are already jumping off the cliff and are able to seriously call this storm a bust when we are still 4.days.out. 

[CentralNC]

Just now, ryan1234 said:

It baffles me that people are already jumping off the cliff and are able to seriously call this storm a bust when we are still 4.days.out. 

Happens every time.

[pbrown85]

So I have seen people talk about the NAM at this range not being accurate, then some people saying that it does a great job with the temp profiles in these situations? Is the NAM to be believed with it showing the cold getting down to upstate SC or are people just hugging the NAM because it shows the temps we need?