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Wintry Palm Sunday NC and VA Winter Storm

Webberweather53

Webberweather53

Meteorologist
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Desert Southwest ?
Given this is only 3 days out now and there’s pretty stout NWP consensus I think it’s time to break out the thread for this event, if busts big deal, most of us have been spoiled beyond belief this winter and esp in March and this storm is just icing on the cake. Let’s reel this one in!
 
The SREFs didn’t look too hot for GSO and RDU last night and neither did the NAM near truncation as well as the CMC. Certainly was nice to see the crappiest models not completely on board this far out, that’s usually a good sign.
 
The 0z UKMET is really suppressed, along/north of the heaviest axis of precipitation stands the best chance for accumulating snow/sleet here. Even though the Triangle and Triad are currently favored, I wouldn't completely go to sleep on this even as far south as Charlotte and Fayetteville if you end up in the heaviest band of precipitation and/or the CAD builds in stronger/faster than forecast, it's a long shot atm but I think much of central NC and VA is fair game until we begin to narrow this down a little more.
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Brick Tamland said:
I'm all about having a fun time.
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This is the kind of storm that has really high bust potential even more so than our last few storms. Whoever ends up underneath the heaviest axis of precipitation Saturday night and Sunday morning is probably going to changeover to heavy wet snow and you're going to be stuck underneath that band for a very long time, which will maximize accumulations. This bonafide clipper event in March 2010 shows what can happen if you hit the sweet spot like those from GSO-Siler City-Dunn did.
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SimeonNC said:
Good or bad sign?

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Really doesn't mean a whole lot in this instance but it shifts the heavier precipitation timing closer to 12z which is favorable for wintry weather in north-central NC. The more noteworthy difference between this run and the 12z is the shift north of the heaviest axis of snow over the Dakotas, MN, and IA.
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Hope this is another case of things looking better as we get closer.
 
The models are putting us out of our misery quickly with this one. 12z runs are terrible for wintry weather around here.
 
Still have 48 hours to go. The runs have been getting better and better. Not jumping because of one run now.
 
Rain Cold said:
The models are putting us out of our misery quickly with this one. 12z runs are terrible for wintry weather around here.
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It's really not that far off from wintry weather, if the rates are heavy enough in this frontogenetical band in the late overnight on Saturday into Sunday, precipitation will changeover to snow. Surface temps are certainly going to be questionable right up to the event given that p-type will be determined by the precipitation rate, strength of the developing CAD dome, and amount of dynamical cooling that's generated by this sheared out s/w all of which NWP models can't adequately resolve. It's not as simple as "oh look the models all show rain now so it's automatically over" and vis versa.

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Webberweather53 said:
It's really not that far off from wintry weather, if the rates are heavy enough in this frontogenetical band in the late overnight on Saturday into Sunday, precipitation will changeover to snow. Surface temps are certainly going to be questionable right up to the event given that p-type will be determined by the precipitation rate, strength of the developing CAD dome, and amount of dynamical cooling that's generated by this sheared out s/w all of which NWP models can't adequately resolve. It's not as simple as "oh look the models all show rain now so it's automatically over" and vis versa.

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I don't disagree. I don't like to see all of the models essentially backing off as we move in, though. That's a red flag for sure, if it continues.
 
I thought overall the models have been trending southward. I wouldn't call one set of runs being different as backing off yet.
 
Definitely some good and bad points to the modeling today so far. Most have shifted the low and stripe of precip further south. However, the stripe of winter weather has not been shifted south to match. Looks like the high pressure has been trending slightly weaker with the 12z runs. I'm curious to what the Euro shows. I think I-40 north is definitely in the game.

By the way, the canadian is definitely further south with the low. Good signs there I think.
 
Rain Cold said:
I don't disagree. I don't like to see all of the models essentially backing off as we move in, though. That's a red flag for sure, if it continues.
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I personally don't see any red flags. If you look at the large-scale conditions, the 850s are below 0C from US 64 north and surface temps are 33-34F, we've seen in the last few events that's very doable (you can actually get away w/ max temps of 1C aloft before dendrites completely melt but that's besides the point) and the timing is optimal during the late overnight period so we don't have to worry about any insolation, etc and there's going to be a lot of lifting in this frontogenetical band. Steady as she goes for now.

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Well one thing that will be a no brainer is that the cad will be stronger than modeled.

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Webberweather53 said:
I personally don't see any red flags. If you look at the large-scale conditions, the 850s are below 0C from US 64 north and surface temps are 33-34F, we've seen in the last few events that's very doable (you can actually get away w/ max temps of 1C aloft before dendrites completely melt but that's besides the point) and the timing is optimal during the late overnight period so we don't have to worry about any insolation, etc and there's going to be a lot of lifting in this frontogenetical band. Steady as she goes for now.

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Ok, I'll stay with you then. :)
 
Rain Cold said:
Ok, I'll stay with you then. :)
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Rain Cold said:
Ok, I'll stay with you then. :)
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Obviously however if this shortwave starts to lift back north and amplifies in subsequent runs, and as we're approaching the event we're several degrees warmer than forecast or the CAD high is slower to move in (we'll likely have some diabatically induced in-situ CAD in any case that's also very difficult to forecast and often missed by the models which may offset this potential negative in the forecast), and/or if the observations upstream in the midwest and OH/TN valleys showed more liquid than frozen vs forecast, then yea I'll be worried. This is the latest in the season I've ever been tracking a winter storm so there's that
 
UK looks interesting, all I see is the 850's and 2m temps. Looks like below -1 to 0C on 850 and 34-35F 2m temps.

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Storm5 said:
Not saying it's wrong but the euro busted horribly for the MA storm yesterday . The snow totals were way way less than what it was showing

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Hater

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Brick Tamland said:
We can definitely work with this.
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Absolutely, especially if your precipitation rates are high enough in that frontogentical band. Models don't handle these processes terribly well and the last few events have overperformed partially as a result of dynamical cooling, sensible heat transfer, etc. Most models only showed a brief period of snow w/ the last event in the morning and it kept snowing at RDU thru the 2 o'clock hour, the preceding event produced accumulating snow even well southeast of RDU down to the coast when most forecasts kept everything NW of the Triangle for the most part...
 
No real changes to the overall thinking here w/ this event if you're along/north of the US HWY 64 corridor, and along/west of I-95 in the northern coastal plain, you stand a legitimate chance to see accumulating snow out of this. It certainly helps when the heaviest precipitation comes late at night when surface temps are coolest.
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