GaWx

It isn’t often that a GEFS day 8 mean SLP is projected to be as high as 1048 mb in the US, but today’s 6Z has that (as of 3Z on Jan 20th): Thanks to a Siberian Express pattern, 11 of the 30 members then have the high 1052+ mb somewhere in the N Rockies or Plains of the US (members 6-8, 14-15, 17-19, 22, 24, 30):

If this model predicted very cold 1/19-25 were to verify, Jan of 2025 would have a good chance to end up the coldest Jan since 2014 (colder than 2018) in the E 1/3 of the US averaged out. Also, going back to 1995, it may be that only 2014 and possibly 2003 would be colder. That would be quite impressive considering global warming!

What do you think about the very strong signal for very cold much of the US 1/19-1/25, which would make Jan of 2025 as quite possibly one of the two coldest Jan’s in the E 1/3 of the US when averaged out since way back in 1994?

Followup: 3-4 days later widespread SE winter storm Jan 10-11/2024 with both heaviest snow to as far back as Jan 9-10 of 2011 and first major winter storm since Feb 12-13 of 2014 some areas

Do you check CoCoRaHS? On that I don’t see anywhere near 5” in that general area for the sum of the two latest 24 hour periods ending ~~7AM. In N Gwinnett 6 miles N of Lawrenceville and 3 miles S of Mall of GA, I measured a solid ~3” based on several measurements in grassy areas (~3.5” for high end). That’s a bit higher than the NWS map implies. The ATL airport measurement of 2.2” is low compared to the city, which probably averaged 3-4”, easily biggest snow since 1/2011. ZR on trees is rather notable but I didn’t actually measure it. My guess: ~0.2-0.25” with pine branches drooping a lot. This probably just missed where widespread outages would have started whew!

There’s been a pretty good amount of ZR here in N Gwinnett that can easily be seen in especially the pines branches, which are leaning noticeably. So far, outages in this area are just a low %. Fortunately, the radar suggests there shouldn’t be too much more rain falling.

Just back from our awesome walk. I love the crunch of the snow! Measured ~3” of wet snow on grass. Lots on trees. Very nice. Saw lots of snowmen. Snow ended couple of hours ago with light mix of IP/ZR since, including during our walk. Lots of slush on roads (due to some traffic) and some on sidewalks. Roads slushy rather than slippery due to temps only barely below 32 (~31-32).

A lot of reports of 3-3.5” in Dekalb county and nearby like on Jimmy Carter in Gwinnett! I’ll check mine here when I actually go outside (Gwinnett). Latest guess 2.5”+. Could be 3”.

It appears the light sleet has changed to freezing rain here in N Gwinnett.

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: