GaWx

I think it’s lightly sleeting here in N Gwinnett after a beautiful ~2” of snow. No matter what happens from this point, making the trip up here from Savannah is guaranteed to have been the right decision!

I’m thrilled with what we already got here. I estimate 2”! The snow has let up considerably. Can’t tell what may be falling now but it’s light.

Probably near 1” here (N Gwinnett) now already! Loving it!

I’m a proud Georgian who has watched the sleet change to all snow last 30 or so minutes! Beautiful and sticking to everything! Easily over 1/2” already from window estimate!

I’m S of Buford ~3 miles S of Mall of GA.

Thank you! Just woke up and looked out window. Can see a tiny accumulation on roofs, grass, and vehicles of what I assume is sleet here 40 miles NE of Atlanta in N Gwinnett county (2 miles S of I-85 and 6 miles N of Lawrenceville).

Wetbulb temps in N GA are only in the middle 20s. I wonder if models are correctly taking this into account. Many keep temps in low 30s with precip, which seems too high!

Lots of sleet reports coming from far N AL especially during the last hour.

Latest Euro weeklies for 1/20-6 keeping in mind that model consensus brings down Siberian Express high ~1/20: Significant Gulf moisture signal is even stronger than prior run:

Tunica, MS, and Memphis went from light sleet/mix last hour to light snow currently. Skies have become mostly cloudy in last hour here 40 miles NE of ATL. I’m excited about the possibilities! Temps near 32 but dewpoints are well down into the teens.

DFW is now at 33F vs 18Z NAM having them at 35F. So, still too warm (by 2F) fwiw.

After seeing the 12Z NAM verifying 4F too warm at DFW this morning, knowing this would likely be biggest ATL area winter storm since 2014, and knowing I had a place to stay, the weenie in me decided to come to ATL area and take a chance it won’t be mainly a damaging major icestorm where I’ll be. Hoping mainly snow and sleet. I’ll be in a more favorable spot thermalwise than downtown as I’ll be in N Gwinnett County between Mall of GA and Lawrenceville (~40 miles NE of ATL itself). I stopped for a break but wanted to note the many power trucks on I-16 heading W toward the winter storm warned area. Also, I saw numerous trees down on the sides through the 50 miles between Metter and Dublin resulting from Hurricane Helene. Never seen anything like it before!

12Z NAM as of 10AM EST (15Z) was ~4F too warm in DFW area (~35F…see map below) vs reality of ~31F with sleet. The others (GEM, HRRR, GFS) are much closer to reality with them all being within 1F. Also, NAM dewpoints are in low 30s vs upper 20s other models and reality. Implications if any? Is NAM going to be too warm at surface in other areas, too? DALLAS/FORT WORTH METROPLEX CITY SKY/WX TMP DP RH WIND PRES REMARKS DFW AIRPORT SLEET 31 28 89 E7 30.25S WCI 24 DALLAS LOVE LGTSLEET 32 27 81 VRB3 30.28R FTW MEACHAM LGT SNOW 30 27 86 SE7 30.25R FOG WCI 23 FTW-NAS-JRB CLOUDY 32 27 81 SE6 30.27R NAM: 35F (4F too warm) The other models are much closer to reality: GEM: 30F (only 1F too cold) HRRR: 32F (only 1F too warm) GFS: 32F (only 1F too warm)

12Z Icon: still has this much “snow” in south-central GA (up to 3.8”), 0.8” here, and 0.2” at Waycross, which all continues to make no sense:

This 12Z HRW FV3 has snow in C GA to ~553 thickness line. Normally snow only goes as far south as ~546-7. Thus, this map looks too generous with snow (too far south with snow line).

Yeah, I’ve also been seeing it on many Icon runs! Now the 0Z Euro joins the party as that is its first run showing wintry precip in SE GA. It has light ZR near Statesboro 8-10 AM Fri with temps hovering near 32 and 850 temps of +2 to +3C. It’s its first run showing this not because it is colder but rather because it has precip breaking out earlier. I wonder if this will keep trending more and more that way. Also, It looks like @Shackgets some ZR on this:

Tony, So it was you that changed 2/1979 to snow very early! Wow, the mystery is finally solved. I was initially very disappointed when the snow changed to sleet way early. Before that there were beautiful flakes accumulating nicely. Little did I know that the sleet would accumulate way more than I thought was even possible and also look as white as snow. Also, I didn’t realize how loud it was. And little did I realize how slow the melting would be in the days to come. Tony, that storm changed my feeling about sleet greatly. From that point on I never again felt negativity about sleet and started to embrace it. I still love snow but since then I’ve loved sleet, too. Sleet isn’t a wicked stepsister to snow anymore. Rather, they’re both beautiful princesses although one is a loudmouth and the other much more reserved. The staying power of 4” of sleet likely usually beats that of 12” of snow. What’s not to like about that?

From KCHS: INITIAL "WARM ADVECTION WING" OF LIGHT PRECIP IS LOOKING NOSE INTO THE LOCAL FORECAST AREA FRIDAY MORNING THROUGH MIDDAY WHICH COULD PRESENT SOME P-TYPE ISSUES FOR INLAND AREAS GIVEN THE LINGERING COLD AIR. INLAND GFS AND ENSEMBLE FORECAST SOUNDINGS FRIDAY MORNING SHOW A DEEP ISOTHERMAL LAYER HOVERING AROUND 0C UP THROUGH ~700 MB AND LOTS OF DRY AIR BELOW WITH WET BULB TEMP PROFILES COMPLETELY BELOW FREEZING...SUGGESTING SOME -SN POTENTIAL. HOWEVER, GIVEN THE DEGREE OF DRY AIR, ANY PRECIP WILL HAVE A HARD TIME ACTUALLY REACHING THE SURFACE. THAT SAID, AFTERNOON FORECAST WILL INTRODUCE A LIGHT SNOW/LIGHT RAIN-SNOW MIX TO INLAND AREAS FRIDAY MORNING BUT WITH NO ACCUMULATION OR IMPACTS ANTICIPATED (MORE LIKELY SPRINKLES OR FLURRIES). Claxton, GA forecast: FRIDAY CLOUDY. A SLIGHT CHANCE OF SNOW IN THE MORNING, THEN A CHANCE OF RAIN IN THE AFTERNOON. LITTLE OR NO SNOW ACCUMULATION. HIGHS AROUND 50. EAST WINDS AROUND 5 MPH. CHANCE OF PRECIPITATION 40 PERCENT.

Only 0.3” downtown ATL! Tight gradient just to the north with 2.7” at Roswell!

How (not) good is the HRRR 36 hours out? Same for RAP. Any opinions?

Tony, You may not remember this but the great 4” Atlanta sleetstorm of 2/18/79 was originally supposed to have much more snow. The snow lasted only for a short time at the start (not much more than an hour, if even that) in the evening before changing to sleet much earlier than expected and lasting for the rest (nearly 24 hours)! Snow remained further to the north. This late became the President’s Day snowstorm in the NE US.

Here we go again with a SE coast major snow teaser run. Like the real ones often do, this crosses S FL. The last umpteen SE coastal teasers haven’t verified but one day or year or decade the next one finally will. I’d just like to see a flake or pellet as it has been 7 years here. Granted the last one was a doozy. Looking ahead, today’s Euro Weekly for 1/20-26 tells me that the next shot at a widespread SE winter storm may come then: H5: strong -EPO/moderate +PNA, which would allow for cross polar air/Siberian Express: 2m temperatures: this is a notably cold signal for still being 12 days out Last but not least is the precip signal, which hints at another Gulf storm:

18Z GFS: generous sleet N GA/NW SC with heaviest 0.7-0.9” Lawrenceville, GA, to Greenwood, SC: @dsaurincluded in sleet area again…May the sleet be with you! Would be heaviest and most widespread sleet for at least N GA since at the very least 2/12-13/2014:

Regarding NAM, what version between 3 km and 12 km is the most accurate (or least inaccurate) for qpf/precip type amounts?

The new Euro Weeklies are the coldest yet for the E US overall for these 2 weeks, which would seal a very cold Jan in the E half of the US overall (-7 to -9 in some places would be quite possible). That would be similar to 2014 and a bit colder than 2018, 2011, 2010, and 2003 overall in the E US. It may turn out the coldest Jan since 1994! 1/13-19: first time with some 4th shade of blue (~11 BN): 1/20-26: largest area of 3rd shade of blue yet (mainly 6-10 BN) Also note the precip signal for 1/20-26: moderate wet signal Gulf to SE VA (Miller A?):