GaWx

The wind here is putting on enough of a show for a wind advisory as the refreshing Canadian air continues to rush in with virtually cloudless skies. Winds have already gusted to as high as 44 mph at the airport! I’ve been needing to clear my roof of leaves/debris. Well, Mother Nature has done me a favor and already cleared a good portion of it today with the yard now a mess! It was ~64 at sunrise and it’s now 60.6. Looking forward to walking!

 Expecting a slow fall the rest of the afternoon as we head for low 30s by morning. Cold wx advisory is out. Tomorrow’s high is forecasted to be only in the upper 40s, which compares to yesterday’s 86. There’s a near 100% chance of a freeze tomorrow night. Expecting freeze watches soon. N FL already has them for tomorrow night.

Edit:

 I forgot to post my rainfall from last night through just after sunrise. I got 0.65”. That added to my 0.75” of Feb 15th gives me a beneficial 1.4” for the 7 day period  ending this morning.

6 minutes ago, Coach McGuirk said:

Ehh, 41.5 now.  Gonna get hard to freezing. 

The model consensus has been suggesting you may bottom out just above 32 but still with snow accumulating, especially on nonpaved surfaces, starting ~4-6PM.

1 hour ago, Coach McGuirk said:

41.0 and rain, not liking the temp and saturation. 

Your 41 and rain matches the model consensus well. It shows you may not fall below 40 til midafternoon with snow starting during the evening.

15 minutes ago, SEwakenosnowforu said:

That's what I mean. These snow totals in VA into South Jersey seem over the top. Even north of there.

They’re crazy high, but this is a crazy strong storm (sub 975 mb) with a lowest at 500 mb of sub 520 and tons of moisture. I mean this is a once in 10+ years kind of deal with crazy heavy snowfall rates that can easily accumulate well on nonpaved surfaces even with temps up to 34-35.

5 minutes ago, SEwakenosnowforu said:

Anybody feel like these totals are exaggerated in many areas? Temps are marginal. Ratios??

Are you looking at 10:1 totals or Kuchera totals? 10:1 are exaggerated where temps are marginal.

25 minutes ago, UnionCountyNCWX said:

Booooooooooo. idk don't have anything to add haha

 I prefer below normal temperatures pretty much on every day of the calendar! I’m consistent because heat and humidity prevail down here way more than I prefer. I’ve been known to escape to the CO Rockies during summer because of this, my favorite time to go there. That’s why I love winter so much here. It’s a very nice reprieve from the oppressive heat and humidity. It’s like a different world.
 

 Keep in mind my climo when I say I prefer BN in winter. BN means highs of mainly 50s-40s and lows of 30s-20s, something I can dress for and enjoy. Now if I were homeless, I’d obviously feel differently. Then I’d want it mild in winter and mainly BN otherwise.
 

 The only very rare exception to wanting a day BN might be if I were to go the beach, which I hardly ever do. But then again, a little BN can still be warm enough.

 The spring….well, practically summer…wx the last 2 days here (85 and 86 record highs at KSAV, which both exceeded forecasts of lower 80s) is about to come to a very welcomed abrupt end. After also a possible record high minimum for today (won’t know til midnight…edit: it turned out to be record high low of 65), the high on Mon may be close to 40 colder and the low on Tue will be close to 40 colder with it flirting with the record 25! So, pseudo-summer record highs to mid-winter conditions/near record lows in the span of just 48 hours! It doesn’t get much more dramatic than this in the temperature swing dept and is the main reason winter is the most interesting season to track. Rarely a dull moment.

2 hours ago, NorthHillsWx said:

It ends February 1 now. Any snow after then is spring snow. This is a spring month now 

 The spring….well, practically summer…wx the last 2 days here (85 and 86 record highs!) is about to come to a very welcomed abrupt end. After also a possible record high minimum for today (won’t know til midnight), the high on Mon may be close to 40 colder and the low on Tue will be close to 40 colder with it flirting with the record 25! So, pseudo-summer record highs to mid-winter conditions/near record lows in the span of just 48 hours! It doesn’t get much more dramatic than this.

 Speaking of spring snow, it appears you guys up there may have a chance in just over a week! Certain model runs sure have been giving y’all the spring snow tease though the ATL area, which has had mainly only a T so far in much of it, has largely been left out of these teases.

85.2 at 1:54 PM. Highest I saw yesterday 84.7.

12Z SV AI Weathernext: DC up to ~7” 10:1 from ~5” 10:1 prior 3 runs; probably ~~5” Kuchera up from ~~4” prior 3 runs

It’s 84.2 here at 1:50PM! At 1 PM, it had already hit 83, just 1F below the daily record high. There are gusty warm SW winds.

Edit: 84.7 at 2:36PM!

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: