Feb 12-13 Sleet/Snow/ZR Event

[packbacker]

Comparing Euro ENS runs the past couple of days…note this is comparing things at day 5 (Wed 12z).

 

0z Feb 6th run - looks very close to the 12z run today, with a few small differences, the HP from todays run is stronger and the SLP down in the gulf is a little quicker, and if anything the HP on today's run is a smidge further west, but you can see the PV trying to push it out of the way on today's run.

 

12z Feb 6th run - the HP on today's run is east of yesterday's 12z run, but it's also further south, which helps some, and it's trying hard to get a banana high wrapped down to Tx, again on today's run the HP looks a tad stronger.

[packfan98]

One run is not a trend.  I think we get on model overload (me included).  Last night's run of the Euro was one of the coldest so I think we can say that the model stopped trending colder.  If it continues to warm on future runs it would be a trend. 

 

Here are the big question marks right now that we won't have the answers to for a couple of more days:

 

1) How strong will the high pressure be? This will affect the surface temperatures.

2) How strong will the northern low be, and where will it be located?  This will let us know how long our cold air will last?

3) How strong will our southern energy be?  This will give us an idea of how strong our gulf low will be.  This affects the storm track and precip amounts.

4) Timing of all of the players. Will the overrunning moisture get in early and give us a good thump of snow before the low starts cranking in the gulf/atlantic?

5) What will the small scale features be?  We will get a better idea when all of the players are on the field and the short-term, hi-res models are useful.  We can look at the temperatures through the entire column and look for the warm noses aloft.  We will get a better idea about snow vs sleet vs freezing rain vs rain and potential transition times.

 

The accumulation predictions have a high bust potential due to the mixed bag.  You may end up with 6 inches of snow, but you would be more likely to end up with 2 inches of concrete (wet snow/ice).  We shall see!

[BIG FROSTY]

This is off 12z EURO. for ( KMWK)I don't see a problem with them temps, but I don't want to see it warm anymore either....  Still a long ways to go!

                               2 M     850s                                   qpf

WED 12Z 12-FEB  -2.7    -3.8    1027      46     100    0.02     561     540   
WED 18Z 12-FEB  -3.2    -0.5    1021      85     100    0.46     560     543   
THU 00Z 13-FEB  -2.3    -1.9    1015      87      93    0.52     554     542   
THU 06Z 13-FEB  -1.0    -2.7    1011      90      70    0.03     551     542   

[Lookout]

What we should be looking at is the trend of the models and the EURO started trending a little warmer the last run which is worrying for those that want sn as we were all pretty borderline for temps to begin with. Still a lot of time for the model waffling to continue and I suspect they will like Robert said.

I'm not sure what euro you are looking at or referring to where but last night's run was quite a bit colder than previous runs, not warmer.

 

As for this run, I still like what I see for the cad areas as far as the surface temp goes. The cad locations of north carolina are obviously going to be well below freezing without much threat of it warming. Same for the upstate. There is just a question of what type of winter precip falls and how much.

 

Further south, the euro at 12z wed has the freezing line along the ga/sc border just east of here..just like the 0z run but  Unlike last night's run though, it doesn't advance it further to the west across the rest of north and central ga. I think that's a bit hard to believe. A CAD signature shows up at 850mb still..that is the sign of a very strong cad event since most cad events are 900 to 925mb and lower. On that alone, this makes this have high potential for a high impact event.

 

The other is this run doesn't destroy the warm nose for a while like the 0z does. And frankly what the 0z run showing that happening would be highly unusual. Even so, it has the 0c 850mb isotherm starting off in the upstate. As I said yesterday, a general rule of thumb is temps will be subfreezing over north ga if the 0c isotherm starts off that far south. If it started up near the nc/va border it would be a different story.

 

The main negative thing I see is that the high over new england is not quite as strong, expansive, and a bit more progressive than last nights run. That is something I don't want to see continue.

 

Otherwise, this run still looks very good for winter precipitation in cad locations in northeast ga and the upstate. Especially considering this is the euro showing temps this cold. Unless they have made some adjustments to correct it's warm bias at the surface, given it's warm bias that is pretty impressive.

 

 

 

Yep, but the overrunning precip that starts hour 84 through 120 is what I am hoping, that may be able to give a lot of places 1-3".  The "big" ice storm is getting really close to being a big rain storm.

Where in the hell are you referring to because that is just nonsense for most. It's also nonsense to say things like this when you are still this far out. . Even if it's a bad run, you don't go making proclamations of it being a bust based on one run. Just like you don't say it's going to be a huge winter storm based off of one run. 

 

Fact is, Not every single run is going to show your dream storm or something perfect. Folks who don't realize this just set themselves up to look foolish and will cause yourself a lot of grief.

[BIG FROSTY]

I'm not sure what euro you are looking at or referring to where but last night's run was quite a bit colder than previous runs, not warmer.

 

As for this run, I still like what I see for the cad areas as far as the surface temp goes. The cad locations of north carolina are obviously going to be well below freezing without much threat of it warming. Same for the upstate. There is just a question of what type of winter precip falls and how much.

 

Further south, the euro at 12z wed has the freezing line along the ga/sc border just east of here..just like the 0z run but  Unlike last night's run though, it doesn't advance it further to the west across the rest of north and central ga. I think that's a bit hard to believe. A CAD signature shows up at 850mb still..that is the sign of a very strong cad event since most cad events are 900 to 925mb and lower. On that alone, this makes this have high potential for a high impact event.

 

The other is this run doesn't destroy the warm nose for a while like the 0z does. And frankly what the 0z run showing that happening would be highly unusual. Even so, it has the 0c 850mb isotherm starting off in the upstate. As I said yesterday, a general rule of thumb is temps will be subfreezing over north ga if the 0c isotherm starts off that far south. If it started up near the nc/va border it would be a different story.

 

The main negative thing I see is that the high over new england is not quite as strong, expansive, and a bit more progressive than last nights run. That is something I don't want to see continue.

 

Otherwise, this run still looks very good for winter precipitation in cad locations in northeast ga and the upstate. Especially considering this is the euro showing temps this cold. Unless they have made some adjustments to correct it's warm bias at the surface, given it's warm bias that is pretty impressive.

That's the one thing I would like to know (have they made adjustments for the warm bias)? Me and a friend were talking about this very thing today? If anybody knows maybe they will chime in.

[Brick Tamland]

Where in the hell are you referring to because that is just nonsense for most. It's also nonsense to say things like this when you are still this far out. . Even if it's a bad run, you don't go making proclamations of it being a bust based on one run. Just like you don't say it's going to be a huge winter storm based off of one run. 

 

Fact is, Not every single run is going to show your dream storm or something perfect. Folks who don't realize this just set themselves up to look foolish and will cause yourself a lot of grief.

 

I don't understand this, either, when it is in direct contradiction to what mets like RaleighWx said about the Euro.

[Lookout]

That's the one thing I would like to know (have they made adjustments for the warm bias)? Me and a friend were talking about this very thing today? If anybody knows maybe they will chime in.

I've been wondering for a while now too...not because its not been too warm but they make adustments on them all the time. it doesn't help that we have had so few cad events the last few years to be able to test it.

[NC_WX10]

18Z NAM  looks good at hour 84 for the initial system on Tuesday. Good amount of precip in WNC and 850's are below zero north of around Charlotte.

[GaWx]

 The 12Z CMC fwiw looks imo like a major ZR for ATL-AHN with 1"+ of qpf and 850's in the crucial +3 to +5 C range along with solid wedging. However, verbatim, it is just like the 12Z Euro with no ZR there.

[beanskip]

Fascinating to compare the 18z NAM 500 mb features to the 12z Euro -- times aren't exactly aligned but the Euro has a nice southern stream disturbance coming on shore at 12z on Feb. 10 and parked over extreme SW N. Mexico at 12z on Feb. 11. Through 6z on the 11th, the 18z NAM shows virtually no southern stream energy at all to speak of.

[Brick Tamland]

oopsie

 

I was agreeing with you about what packbacker said. I was saying what he said was contradicting to what RaleighWx said about the Euro still showing a significant winter storm.

[Lookout]

I was agreeing with you about what packbacker said. I was saying what he said was contradicting to what RaleighWx said about the Euro still showing a signifigant winter storm.

DOH! Ugh..sorry...I completely read that one wrong lol. I'll delete that post.

[Wow]

12z Euro at 120 hrs... there's your CAD sig

 

[NEGa]

I'm not sure what euro you are looking at or referring to where but last night's run was quite a bit colder than previous runs, not warmer.

 

As for this run, I still like what I see for the cad areas as far as the surface temp goes. The cad locations of north carolina are obviously going to be well below freezing without much threat of it warming. Same for the upstate. There is just a question of what type of winter precip falls and how much.

 

Further south, the euro at 12z wed has the freezing line along the ga/sc border just east of here..just like the 0z run but  Unlike last night's run though, it doesn't advance it further to the west across the rest of north and central ga. I think that's a bit hard to believe. A CAD signature shows up at 850mb still..that is the sign of a very strong cad event since most cad events are 900 to 925mb and lower. On that alone, this makes this have high potential for a high impact event.

 

The other is this run doesn't destroy the warm nose for a while like the 0z does. And frankly what the 0z run showing that happening would be highly unusual. Even so, it has the 0c 850mb isotherm starting off in the upstate. As I said yesterday, a general rule of thumb is temps will be subfreezing over north ga if the 0c isotherm starts off that far south. If it started up near the nc/va border it would be a different story.

 

The main negative thing I see is that the high over new england is not quite as strong, expansive, and a bit more progressive than last nights run. That is something I don't want to see continue.

 

Otherwise, this run still looks very good for winter precipitation in cad locations in northeast ga and the upstate. Especially considering this is the euro showing temps this cold. Unless they have made some adjustments to correct it's warm bias at the surface, given it's warm bias that is pretty impressive.

 

 

 

Where in the hell are you referring to because that is just nonsense for most. It's also nonsense to say things like this when you are still this far out. . Even if it's a bad run, you don't go making proclamations of it being a bust based on one run. Just like you don't say it's going to be a huge winter storm based off of one run. 

 

Fact is, Not every single run is going to show your dream storm or something perfect. Folks who don't realize this just set themselves up to look foolish and will cause yourself a lot of grief.

 

fwiw i agree - this is starting to look like the "classic" cad events here in the early 2000s before they just stopped in dec 05

 

i would be ecstatic to have an initial thump of snow, but thats iffy with cads.  however, if it is as deep as progged at the 850 level its possible.  would be kind of cool to have the whole gamut from snow to sleet to freezing rain

 

hopefully people can temper expectations - as for n ga most of the time its frz rain so anything would be a bonus in my book. extreme solutions show up but of course rarely materialize (thats why they are extreme and rare lol). fortunately, i am one of the weenies who likes all frozen precip (granted i would prefer not to have all the trees etc. come down, but we dont really have any say in the matter). i am starting to get a bit more excited at the prospects of a pretty decent wide spread se winter event

[RaleighWx]

Fascinating to compare the 18z NAM 500 mb features to the 12z Euro -- times aren't exactly aligned but the Euro has a nice southern stream disturbance coming on shore at 12z on Feb. 10 and parked over extreme SW N. Mexico at 12z on Feb. 11. Through 6z on the 11th, the 18z NAM shows virtually no southern stream energy at all to speak of.

 

I see a s/w over AZ on the 18z NAM at hour 84.

[MillerA]

From Allan Huffman tweets. 15Z sref probability of >1 through 87

Check out @RaleighWx's Tweet: https://twitter.com/RaleighWx/status/431898511185956864

[BullCityWx]

12z Euro at 120 hrs... there's your CAD sig

 

 

old school map!

[beanskip]

I see a s/w over AZ on the 18z NAM at hour 84.

 

Well, I was looking at this:

 

http://mag.ncep.noaa.gov/Image.php?image=data%2Fnam%2F18%2Fnam_namer_084_500_vort_ht.gif&model=nam&area=namer&storm=&cycle=18&param=500_vort_ht&fhr=084&group=Model+Guidance&imageSize=M&scrollx=0&scrolly=0

 

I guess there is a little hint of energy, but didn't seem like anything on the scale of the Euro -- but it could be yet another case of me not knowing what I'm talking about.

[RaleighWx]

Well, I was looking at this:

 

http://mag.ncep.noaa.gov/Image.php?image=data%2Fnam%2F18%2Fnam_namer_084_500_vort_ht.gif&model=nam&area=namer&storm=&cycle=18&param=500_vort_ht&fhr=084&group=Model+Guidance&imageSize=M&scrollx=0&scrolly=0

 

I guess there is a little hint of energy, but didn't seem like anything on the scale of the Euro -- but it could be yet another case of me not knowing what I'm talking about.

 

LOL. IN this overrunning pattern the impulses can be somewhat subtle. Here is the vort map.

 

There is a WSW flow all the way basically from the 4 corners to the Carolinas. This is a tricky pattern and the type where you may see something show up in the models 24-36 hours out that you didnt see coming until then. Because of the parade of impulses that will be difficult to time.

[Wow]

old school map!

 

Yeah, broke out the old plymouth maps to show pressures at 1mb contour intervals.  If this storm can move in a few hours earlier where the HP is positioned at 120, we'd all be digging out.

[beanskip]

Thanks, that helps -- it is true, isn't it, that the Euro is showing this feature as much stronger and more consolidated? Or, am I simply a victim of map scaling?

 

 

 

LOL. IN this overrunning pattern the impulses can be somewhat subtle. Here is the vort map.

 

There is a WSW flow all the way basically from the 4 corners to the Carolinas. This is a tricky pattern and the type where you may see something show up in the models 24-36 hours out that you didnt see coming until then. Because of the parade of impulses that will be difficult to time.

 

[packbacker]

I was agreeing with you about what packbacker said. I was saying what he said was contradicting to what RaleighWx said about the Euro still showing a significant winter storm.

I never contradicted RaleighWx, I just said for places like GSO, INT and CLT is mostly all frzn, RDU had a lot of frzn but then flips to rain, per the Euro. Read more post less.

[RaleighWx]

Thanks, that helps -- it is true, isn't it, that the Euro is showing this feature as much stronger and more consolidated? Or, am I simply a victim of map scaling?

 

Euro5h.gif

The Euro has a more neutral tilt and is a little bit better defined than the Euro at that time frame. The NAM s/w is  positively tilted and a bit weaker.

[DaculaWeather]

SENIOR DUTY METEOROLOGIST NWS ADMINISTRATIVE MESSAGE
NWS NCEP CENTRAL OPERATIONS COLLEGE PARK MD
2132Z FRI FEB 07 2014

GOES-W RSO WILL BE IN PLACE ON SATURDAY FROM 1529Z-0329Z IN
SUPPORT OF ATMOSPHERIC RIVER MONITORING AT WFO MONTEREY.


HANDEL/SDM/NCO/NCEP

[beanskip]

Thanks -- love to learn!

The Euro has a more neutral tilt and is a little bit better defined than the Euro at that time frame. The NAM s/w is  positively tilted and a bit weaker.

[oconeexman]

fwiw i agree - this is starting to look like the "classic" cad events here in the early 2000s before they just stopped in dec 05

i would be ecstatic to have an initial thump of snow, but thats iffy with cads. however, if it is as deep as progged at the 850 level its possible. would be kind of cool to have the whole gamut from snow to sleet to freezing rain

hopefully people can temper expectations - as for n ga most of the time its frz rain so anything would be a bonus in my book. extreme solutions show up but of course rarely materialize (thats why they are extreme and rare lol). fortunately, i am one of the weenies who likes all frozen precip (granted i would prefer not to have all the trees etc. come down, but we dont really have any say in the matter). i am starting to get a bit more excited at the prospects of a pretty decent wide spread se winter event

Man its hard not to get overly excited about a true CAD winter event. As Lookout, Robert and a few others said early in winter that are chances are really good this winter for an old fashioned cad event. We had numerous cad rains this fall and are so long overdue for a winter storm with cad in place. There are a lot of things in play next week but with some good timing and a strong enough/well placed High we will be sitting pretty!

Looking forward to the CAD refresher training Lookout will be posting this weekend! Lol

[packbacker]

IMO, GFS likely to supressed with that overrunning precip day 4, that could trend real nicely.

[Wow]

GFS looks even weaker with the s/w.   Hardly even a low registering in the gulf by 108.  Just can seems to shake off that old MRF bias.

[burgertime]

The 18z is dumpster fire bad looking. That energy in the south looks horrid. 

[Wow]

The 18z is dumpster fire bad looking. That energy in the south looks horrid. 

 

Good memories... Euro on top with the big storm and the GFS killing it off as passes it as a weak wave crawling along the gulf coast.