GaWx

14 minutes ago, WXNewton said:

I kept track of QPF out put from all models for several days before the storm for MBY HKY. 2-3 days out GFS output ranged in the .65"-.8" range and GEFS was consistently around the .5"-.55" range. The Euro was consistently around the .35-.45" range and the EPS was around .45" -.5" range. We wound up receiving about .52-.54" of precip. Both AI models nailed the .7-.8" totals near and around CLT to Salisbury. I think general rule of thumb you stick with ensembles and blend those together and you will get a pretty accurate look at what's going to happen starting in the next 12 to 24 hours.

 GFS seems to have a bit of a too heavy QPF bias in general. Not for all cases by any means but averaged out, which would fit the definition of a bias.
 Any other opinions on this?

Teleconnections have been steady for Feb 22-23 with MJO phase 3 (coldest Feb phase for La Niña on avg), strong -EPO/-WPO/-PNA/+NAO, and near neutral AO.

6Z SV AI-Weathernext 10:1 mean (see below) as well as the 0Z and 18Z have been consistent on going with ~5” for DC: perhaps that would imply ~4” Kuchera, which seems to be a reasonable possibility at this stage (significant event if it verifies)

53 minutes ago, NorthHillsWx said:

Almost the entire southeast is now in severe drought with extreme drought quickly expanding.  Last weekends rain did very little and this week drying up has turned away yet another opportunity to dent the drought. We could really use a gfs-like scenario for drought relief with Sundays system 

I wonder if the GFS is once again way overdoing the qpf like it did for the 1/25 storm. Some runs had 3”+ of qpf at ATL just a few days in advance but they ended up with only 0.85”. If so, it would likely gradually reduce it from run to run.

4 hours ago, Met1985 said:

It has support from the Ensembles that there will be a storm. Not the crazy totals but it's not bone dry like the Euro is.

 
 The 18Z GFS suite surpringly pretty much held close to the 12Z. Also, the 18Z Euro suites (regular and AI) all got snowier.

 @donsutherland1has done some excellent analyses showing that a -PNA in Feb, especially second half, isn’t negatively correlated to the chance for a big NYC snowstorm.

 I decided to just look specifically at -ENSO NYC Feb 5”+ snowstorms since 1950 and found that the NYC median was a very weak -PNA (essentially neutral) for the entire Feb during -ENSO:

19 NYC 5”+ Feb Nina or cold neutral: PNA

2/1/57 -1.2

2/7/67 +0.7

2/19/72 -0.5

2/23-4/72 -0.5

2/8/74 -0.2

2/12/75 -0.8

2/7/79 -1.1

2/19/79 -0.1

2/5-6/85 -0.8

2/2-3/96 +0.7

2/16/96 -0.4

2/22/01 +0.4

2/12/06 +1.7

2/22/08 +0.7

2/8-9/13 +0.4

2/3/14 -1.1

2/13-14/14 -1.0

2/9/17 +0.7

2/1/21 0.0

Median -0.2

Mean -0.1

Range +1.7 to -1.2

 So, this suggests that during -ENSO throughout Feb that a -PNA doesn’t hurt significant snow chances at NYC. That being said, the last few 0Z GEFS PNA progs have been going with ~-1.2 for the crucial period, Feb 21-22. If -1.2 were to verify, that would be at/near the lowest PNAs for a Feb La Niña 5”+ NYC snowstorm since 1950, which are -1.2 for 2/1/57, -1.1 for 2/7/79, -1.1 for 2/3/14, and -1.0 for 2/13-14/14. 

—————

 Aside: I want to also mention that I had already done a similar study for DC although I used a lower threshold for there due to lower snow climo, 3”, which like for NYC resulted in a sample of 19 storms. Here are those DC results, which are a bit more +PNA favored for -ENSO during Feb:

Median +0.3

Mean +0.2

Range +1.7 to -1.1

—————

 So, NYC has done better than DC during -ENSO Febs when there was a -PNA. In other words, unlike NYC, DC has done a little better with +PNAs than -PNAs.

17 minutes ago, TSSN+ said:

Remember when it showed 15”? Another clunker model 

 Indeed, the SV AI-Weathernext has been terrible because it’s been all over the place, especially for an ensemble mean! The heaviest I’ve posted was this one, the 6Z 2/17 run giving DC ~10” and ~12” for its Mid-Atlantic max centered over C DE:

 Compare that to the latest (today’s 6Z): DC ~3” with none of the Mid-Atlantic >4”:

 In case it wasn’t posted, here’s the SV 6Z AI-Weathernext ens: averaging 3” for this area based on 10:1

1 hour ago, EastonSN+ said:

Still too slow to reach 7. If the lag is 5 days the effects would be felt between the 11th and 15th.

1. Note that the 2/22-23 snowstorm threat period remains mainly in phase 3, the coldest phase on avg during La Niña Febs.

2. When I calculate avg temperatures associated with each phase, I’m not assuming any lag. So, during La Niña, phase 3 was coldest on avg in Feb and phase 7 was coldest on avg in Mar, each with no lag. But also keep in mind that these are merely averages being the coldest along with spreads that cover MB to MA. 
 

 For example:

1) For the coldest La Niña phase in Feb on avg, phase 3:

Avg -107/73 days = -1.5, which is 4F colder than the La Niña Feb phase average of +2.5 and has easily averaged the coldest phase.

 Breakdown of the 18 different Feb La Nina phase 3 periods: wide range but more B/MB (7) than A/MA (5)

MB: 1
B: 6
N: 6
A: 3
MA: 2

—————

2) For the coldest La Niña phase in Mar on avg, phase 7:

Avg -135/81 days = -1.7, which is 2.4F colder than the La Niña Mar average of +0.7 and has averaged the coldest phase.

 Breakdown of the 18 different Mar La Nina phase 7 periods: wide range but more B/MB (8) than A/MA (6)

MB: 2
B: 6
N: 4
A: 3
MA: 3

1 hour ago, cbmclean said:

OK, honest thermodynamics/atmospheric physics questions that has puzzled me for a long time.  Right now my temp is 60.3 °.  Temps are dropping very slowly.  Sometimes on nights like tonight's the temps completely steady out.  The ground is warm so it radiates energy at a high rate.  To slow (or even stop) the temperature decrease, something must be adding energy, but what is it?  The sky is clear so there is no downwelling radiation from clouds.  There is no wind so there is no warm-air advection or turbulent mixing.  Where is the energy coming from?  Is it radiating from the water vapor in the air?     

What NorthHills said. In addition, dewpoints are relatively high (mid 50s). So, even with clear skies, the high RH (70%+) isn’t conducive for strong radiational cooling as the water vapor acts as a blanket (kind of what you were speculating).

 As posted earlier, MJO phase 3 is a plus based on it having been the coldest phase on avg in Feb during La Niña. However, the GEFS progged strong -PNA presents a challenge to getting a significant snow per daily PNAs since 1950.

For the 19 DC 3”+ snowstorms during the 40 La Nina or cold neutral Febs since 1950, here were the daily PNAs:

2/11/25 +0.9

2/25-6/14 +0.5

2/13/14 -1.1

2/12/06 +1.7

2/8/97 +0.5

2/16/96 -0.4

2/2/96 +0.7

2/4/95 +1.6

2/24/86 +0.3

2/22/86 -0.4

2/4/75 -0.3

2/8/74 -0.2

2/19/72 -0.5

2/17/72 -0.7

2/2/72 -1.1

2/17/67 +0.3

2/7/67 +0.7

2/13/60 +0.2

2/7/51 +0.3

Median +0.3

Mean +0.2

Highest +1.7

Lowest -1.1

Feb 8th GEFS PNA for 2/22-3: ~-1.2

 So, should the PNA verify close to this GEFS run and there be 3”+, this would be near the lowest PNA for a DC Feb 3”+ snowstorm during La Niña since 1950. Thus, for a better shot at 3”+, I’d rather the PNA trend less negative.

4 minutes ago, winter_warlock said:

Does anyone really even have any faith in this model?

 Nobody should ever have faith in any model. But Weathernext was pretty good for some storms this winter.

12Z AI Weathernext2 SV: DC 6” vs 8” on 6Z

2 hours ago, LakePaste25 said:

Who is ready for more winter at the end of March? 

 

Me. I’m always desiring BN temps any time of year. BN in late Mar and Apr with relatively low dewpoints is generally delightful and great for outdoor activities here.

Today’s Euro Weeklies 2m anom for 3/23-29:

13 minutes ago, NorthArlington101 said:

wxbell

12Z Euro SV 10:1 is much different in many areas, including DC where it has 2” vs almost nothing on WB Kuchera. Opinions? Does it make sense that Kuchera would be much lighter there? Are temps that borderline?

3 minutes ago, MDSnow93 said:

Well that's kind of what I'm saying. Why are we taking its snow maps seriously if that's a known issue?

I think many (like me) cut Euro AI clown map amounts way down from what it shows when way above consensus.

5 minutes ago, MDSnow93 said:

I still don't really understand the praise the Euro AI is getting.. I was really rooting for the crew that puts it on a pedestal, because it was one of, if not the last model giving us snow this past weekend. Here's what it was showing on Friday and Saturday for Sunday's storm. 

I'm pretty sure nobody in MD saw a single flake.

It is well-known that the Euro AIFS tends to show quite a bit too much snow and to thus not take it literally. Plus it shows as 10:1 instead of Kuchera on WB. Just look at it more for run to run trends is my recommendation. For amounts, I much prefer the regular Euro.

27 minutes ago, SomeguyfromTakomaPark said:

Anyone got the 12z weathernext?

It will likely be awhile. Maybe after 2PM for Weathernext2.

 The model consensus is still forecasting the MJO to be in or near phase 3 for Feb 22-23. Phase 3 has been the coldest MJO phase (based on Baltimore as a representative city) by a good margin when averaged out day by day during the 20 La Niña Februaries since 1975. It has averaged 4 F colder than the avg anomaly for all 566 Feb Niña days since 1975. Keep in mind that Feb Niña has averaged ~2 AN, which is intuitive.

 Regardless, the GEFS progged strong -PNA presents its own challenge.

11 minutes ago, mitchnick said:

I don't know. But thought I'd mention it because I  would guess it's a possibility. You know us snow weenies...terribly vindictive! Lol

Even if Weathernext2 is also off by one color, it would still be 6” at DC. I’d think 6” would be bordering on a  “major” hit there considering that I saw a stat that only 0.7 5”+ snowstorms hit DC each year at this link meaning many years don’t even get a 5” storm:

https://downloads.regulations.gov/FWS-R5-ES-2016-0030-0073/attachment_18.pdf#:~:text=For four days a year on average%2C,events that occur about twice a decade.

5 minutes ago, mitchnick said:

Keep in mind that the SV scale is off by 1, at least on the Euro I know it is. So if you're in the color scale says 6"+, it's  really 4"+.

Is the SV color scale off on AI Weathernext2, too? How would we know?

33 minutes ago, EastonSN+ said:

Still not getting there fast enough

Keep in mind that phase 3 has on average been the coldest phase during the 20 La Niña Februaries since 1975. Note that the upcoming snowstorm threat period of Feb 22-23 centered on the Mid Atlantic is forecasted to be in or very near phase 3 fwiw all the while fighting the making it a challenge progged strong -PNA.

6Z SV AI Weathernext2: 8” DC

1 hour ago, Upstate Tiger said:

A quick AI search reports Washington Reagan 8.6" with annual seasonal average of 14".

NY City has received 21.2" with a 25 year seasonal average of 29".

I have measured just over 11" total in Lincoln County this season. My annual average states 5”.  

 You set up a good example of what I was referring to in my last post. If someone from Lincoln County, which has gone well over climo this winter with 11”, had moved to NYC for more snow this winter, he/she despite getting double that as of now (21.2” vs 11”) might end up mad if that were to be about it for the winter (that’s very doubtful though as this next storm could give them a lot but that’s beside my point). Why not be happy they got 10” more to enjoy as a result of moving? That’s why moving north often doesn’t work like one expected.

Today’s Euro Weeklies are cooler but only in the shorter term (week of 2/23-3/1), which covers the latter portion of the expected storm that’s being heavily discussed:

Yesterday’s 2/23-3/1:

Today’s 2/23-3/1 has a colder signal: