SnowGoose69

6 minutes ago, LithiaWx said:

10” lollipop over west ATL.  Hard to ignore the signals that we get more than the inch or so forecast.  

Dewpoints just seem too high right now.  If those do no start dropping I don't see how any significant snow occurs there

I would not even bother with the GFS at this point for thermals.  Use it for precip axis only and maybe storm track

2 minutes ago, DopplerWx said:

hrrr tomorrow afternoon, no snow to be found in ga, sc or much of nc. 

The RGEM even shows the R/S line going north after 20Z in GA due to precip shutting off or slowing down.

RGEM snow maps make no sense.  Seems to show significant snow at ATL but the ptype algorithm on TT shows mostly rain other than a brief 3 hour period

RGEM on ptype maps appears to be mostly rain at ATL other than from 15-18Z or so.

1 minute ago, lilj4425 said:

These dang models won’t stop flip flopping. HRRR came in worse but NAM and SREF came in colder. Do something isohume. 

Don't use the HRRR that far out.

The 00Z NAM to me looks like it slide south across GA/AL.  Thats purely looking at precip field...not thermals

5 minutes ago, SN_Lover said:

Let me tell you the tale of a snowstorm with no parent high. It was the eve of a storm system, all the weenies gleaming at the models sudden "trend". Weenies wake up and all is cold, then when rain arrives all is toasty. Weenies disappoint and vent on Americanwx. 

I know last year that ATL got their first ever severe freezing rain event without a wedge so anything can happen

4 minutes ago, mackerel_sky said:

The 540 line being in TN, is not a concern!??

I'm sure people here know better than me but I want to say GA commonly snows with thicknesses over 540

11 minutes ago, burrel2 said:

18z RGEM just showed up...

Almost has ATL in rain now.  Its definitely been coming north with time

2 minutes ago, LovingGulfLows said:

 

Well it looks like this time around, they're diverging. HRRR trending slightly cooler and NAM is trending slightly warmer. HRRR is way better for the Atlanta area than the recent 18z NAM run/

I can’t tell really on the 12Z RGEM but it appears to be not as amped as the 18z NAM in your area either.  The ukmet is darn close though.  850 is like -0.4C in ATL the entire event 

It sucks not having the RGEM because it can really let you know if the NAM is out to lunch or not 

1 minute ago, mackerel_sky said:

We toss the RAP! It slides the Mack snow hole into GA , over towards Lookouts area, and gives me 4"! I'll take 1" accounting for warm ground , sun angle, and mixing issues! The Euro and EPS, kind of did the same thing! 

Be real careful with the warm ground deal.  I find that doesn’t work often.  If you’ve got a December sun angle and you snow even one half inch per hour the warm ground deal doesn’t often hold up.  Many places jn GA have been in the 40s now for 36 hours plus.  I always bring up Albany NY being 85 degrees and then seeing 15 inches of snow the next day 

2 minutes ago, LovingGulfLows said:

 

Surprised you're still so hung up on the GEFS...it was a huge failure last winter. Every member had me getting at least 2 inches of snow in the January storm. Nada.

The GFS didn’t see the warm nose in that storm.  Unfortunately the nws and many forecasters bought into it partially and kept snow totals too high when it was evident the event was likely going to be mostly FZRA 

10 minutes ago, neatlburbwthrguy said:

When does ATL decide on WINTER STORM WATCH or WINTER WEATHER ADVISORY?  Figured it would be out by now.   I think criteria for ATL to be in a watch is the expectation for 2 inches of snow.   Saving grace tomorrow for ATL roads will be 34-35 degree temps versus upper 20's we had during SNOWJAM.  

I would be shocked if ATL got anything big from this.  It’s possible but making a forecast here you really have to go just up to 2 inches on cold surfaces.  This isn’t a closed low or dynamic system where intense rates are likely and it’s occurring at a bad time of day for accumulation.  One factor I think that is killing this for ATL is what I call “early wet bulbing” where you get precip too early before dry air really works in and when you finally do start going to all snow you don’t have the potential you would have had if you stayed dry.  If for whatever reason the precip from 23-07Z stays south of ATL and they can get to 23-24-25 on dewpointa this even becomes much more dangerous for them  

1 minute ago, LovingGulfLows said:

 

Seriously, the RAP did the same thing in January. Showed my area getting heavy snowfall through dynamic cooling; In the end, nothing but rain with some sleet mixed in all day and snow showers and flurries the last hour or two. It puts too much emphasis on cooling the colomn along with overestimating the rates of precipitation. There's not going to be a wide area where rates overcome 35-37 degree temperatures.

That event had a lousier cold air supply and was more dynamic forcing mild air into the 750-900 layer

Just now, snowlover91 said:

Yep, it appears the GFS/EURO have this one down. I thought the GFS was out to lunch but it certainly has held firm and seems like it may be closest to reality. 

The Euro wasn’t similar to the GFS in AL/GA/MS really.  More for areas north.  The Euro had 4-5 inches of snow in ATL while the GFS had none 

13 minutes ago, shahroz98 said:

RGEM has a warm nose killing off any wintry precip just east of Atlanta and beyond. I dont know how reliable that model is but its sorta falling in with the NAM and GFS at this point ):

It was much wetter overall than the NAM 

And the 18Z NavGEM looks more west than the 12.  At least we know some models, even if it’s the bad ones aren’t giving in  

Just now, Buddy1987 said:

I am just slightly confused by this. So it is not as amped as last run? Or is the precip coverage better this go around?

Through late Friday afternoon it appeared like it was going to possibly came way west but then thereafter that it appeared to be flatter and more east.  It was definitely more west for AL/GA on the precip but areas further up the MA region it was more east and drier 

The new SREF definitely sort of hints what the Euro showed.  Things looked better thru 54-57 then it wasn’t as good as the previous run after that especially more north 

The Op Euro since the upgrade 2 winters ago in systems that aren’t overly strong at the surface has tended to have a flat bias.  I think the ensembles are definitely going to be more north and west.   The Euro also tends to make slow adjustments.  Sometimes if models are catching onto the setup late the Euro can still be making adjustments inside 12-18 hours 

2 minutes ago, WarmNose said:

Any veterans on here have examples of winter storms where cold air came from west of the Apps where a warm nose wasn't an issue? Thanks 

Many cases where the low is above 995-998mb it’s happened 

2 minutes ago, Cold Rain said:

I have seen the UK be amped too much at this range many times, as well as the CMC.  Throwing the NAM in the trash for now, I'm not discounting an amped solution, but I think the UK today is about the apex of amplification.  My gut feeling is that we see a less amped solution that gets plenty of moisture back west, but temps are so marginal, only western areas will have any shot at slushy accums.  Even there, it should be a struggle.

The last few years when the NavGem has been this far north and west at this range it’s rarely not led to the flatter models coming further west 

1 minute ago, Lookout said:

not surprising it would be warmer...looks like it's well north of every other model with the surface low. 

It’s hard to know without details but the UKMET I’m guessing wouldn’t even be snow in ATL.  That’s probably the more classic BHM-RMG-CHA snow track