GaWx

This is Atlanta’s forecast: What’s with the “very light” drizzle? Isn’t drizzle all very light by definition? REST OF TODAY CLOUDY. SHOWERS EARLY THIS MORNING, THEN A SLIGHT CHANCE OF SHOWERS AND VERY LIGHT DRIZZLE THIS AFTERNOON. HIGHS IN THE UPPER 40S. NORTHEAST WINDS 5 TO 10 MPH. CHANCE OF RAIN 80 PERCENT. TONIGHT MOSTLY CLOUDY WITH A SLIGHT CHANCE OF VERY LIGHT DRIZZLE IN THE EVENING

Here’s the main change for Wake county, which is for tonight and which lead to the WSW: TONIGHT CLOUDY. SNOW, SLEET WITH A SLIGHT CHANCE OF FREEZING RAIN IN THE EVENING, THEN A CHANCE OF SNOW AFTER MIDNIGHT. ADDITIONAL SNOW AND SLEET ACCUMULATION UP TO 1 INCH. Prior to this, they had “little or no” additional accumulation tonight.

3K 6Z NAM 850 0C line is much further north than the 0Z. Now it has significant sleet in RDU!

Sounds good to me, Tony! And as Tony has often reminded us, don’t write off winter til after the Masters (mid April)! In the meantime, a full 5 weeks before the Masters, the 0Z EPS continues to show influence from a famous purple dinosaur (not dsaur lol): check out the cross polar flow! Coldest anomalies for any land region in the N Hem…sound familiar?

0Z Euro Kuchera: up slightly at RDU to 2.6” from 2.4”/2.3” prior two runs: RDU qpf 0.29” (nearly) all falling as snow; slightly higher than prior 4 runs (they were 0.25-0.26”):

For the record to help evaluate model performance, 0Z UKMET for RDU dropped to 0.9” snow on 10:1 of qpf. 100% snow. Last runs starting with 0Z 2/17 run: 1.9”, 0.6”, 2.1”, 1.5”, 1.4”, 2.2”, 0.9”. So, UK has been drier than most models since the 0Z 2/17 run. Before that, UK was among the snowier models with 5.5” on 12Z 2/16 run. These are Pivotal 10:1 snow amounts. In these cases they were usable because the precip has been almost all snow since the 12Z 2/16 run.

No, I know:

Very much fwiw, I think Barney hacked the 360 hour 12Z EPS and GEFS:

If the thunderstorms do exist, wouId high resolution be more accurate?

3km vs 12km 18Z WB NAM Kuchera: RDU 4.0” on both 3 km: 12 km:

The 18Z 12km NAM has the low further offshore than the 12Z.

Thanks. However, this map is from the GEFS rather than the GFS. You mentioned the GFS and it is colder. You had said: “12z gfs looks like nam-12km as well with 850s up in northern wake”

Do you have a 12Z GFS 850 mb map showing this? I’d like to see it. At 3 hour intervals (based on cross checking Pivotal), this TT GFS 850 map (hour 30) is the warmest at Wake and 0C is almost as far S as the S Wake border leaving RDU at -1C:

Today’s preliminary CPC PNA of +1.39 is the highest daily CPC PNA of this winter. And it will be rising further with a target near +1.75 ~Feb 21st. That would be the highest CPC PNA on any winter day since 12/7/2020! Per GEFS, I’m currently projecting a Feb CPC PNA of ~+1.60. That along with the +1.70 of Dec and +1.05 of Jan would give a DJF averaged CPC PNA of +1.45. The current highest DJF averaged CPC PNA (back to 1950-1) are the +1.43 of 2015-6 and the +1.41 of 1976-7, both El Niños. So, 2024-5 still has a shot at having the strongest DJF averaged CPC PNA on record (back to 1950-1). It will obliterate the current highest La Niña CPC PNA of +0.89 (2000-01). Note that I was careful to always call this the “CPC PNA” as opposed to just “PNA” due to Chuck and others questioning the CPC calculations of the CPC PNA in parts of late Jan and early Feb.

Check out how much colder is the 3 km vs 12 km 12Z NAM at RDU: 3 km: <0C at 850 at 4PM, similar to globals 12 km: >0C at 850 at 4PM, warmer than globals; it has a 2 mb stronger surface low and the low is quite a bit N of 3km position

Yes, the 12km 12Z NAM does have a good bit of sleet along with 850s getting above 0C. But the 3km is several degrees colder at 850/never getting above 0C. The globals are similar to the 12km NAM in that respect. I think some sleet is possible but no ZR and mainly snow is what I expect as of now in RDU.

I still don’t see much if any mixing of non-snow precip in the RDU area. This looks like a classic practically all snow Miller A there imo (maybe just a little sleet). 850s look to stay safely <0C from what I’ve been seeing. You may even get a little higher than 10:1 ratios of snow.

It would be pretty remarkable if early March is also cold with it being La Niña. That’s somewhat favored during El Niño, not La Niña. But this winter has been unusual overall with regard to ENSO. Also, the coldest periods with the TPV lobes bringing the E US cold during very strong/near record strong SPV periods has been anything but normal.

Is WXBell down for anyone else? It’s been that way for me for 1/2 hour+.

Have the weenies messed up WxBell? Meanwhile, the 12Z GFS was interesting with accumulating snow just west of ATL tomorrow near and soon after sunrise. But admittedly that’s likely overdone and is an outlier, regardless.

And Barney returns! I’d love for this to verify just for the cold. But it is just a fantasy range 12Z GFS op run which looks totally different from prior runs. So, this has no more than entertainment value, of course. It will likely be far different on the Happy Hour run.

Meanwhile, 12Z UKMET at RDU dropped back from the 2.1” of the 0Z run, to 1.5” on the 6Z and to 1.4” on the 12Z. The qpf on the 12Z is ~0.13”. It looks like to me that just about all of the precip at RDU will be snow per general model consensus.

0Z Euro: 2.5” Kuchera RDU from 0.25” qpf

Why are 0Z 12K NAM 850s 3-4C warmer than 3K NAM’s for RDU?

0Z UK for RDU: highest since 12Z of Sunday with 2.1” of pure snow from 0.2” of qpf.