A light layer of sleet covers Raleigh at this hour. There will be a lull in the precipitation for a bit as the areal coverage increases overnight. The question becomes… how much more sleet can we sneak in before it turns to all freezing rain?
Trends this evening indicate that the freezing rain will win out sooner than hoped. Unfortunately, this means that a majority of the remaining precipitation will fall in the form of freezing rain. The good news is that short-term modeling also suggests lower QPF (quantitative precipitation forecast) than we had earlier feared.
Net, net… Raleigh looks to be in line for 1/2–3/4″ of sleet/snow and 0.5–0.7″ of ice accrual. Numerous downed trees and power lines will make power outages widespread.
Nothing much to change from the previous thinking. But I do have a couple of musings…
° There will be a line of thunderstorms trailing the low on the warm side of the storm as it makes its way east. I wonder if the convection gets cranking, if there might be a moisture rob. Will the convection inhibit the transport of moisture to the north? No evidence of that, just something to keep an eye on, which would have the potential to reduce precip totals.
° That line will ultimately end up sweeping thru our area. I wonder if there may be convection this far north. If so, there may be some gusty winds entrained down to the boundary layer. Normally not an issue, but if you have ±1/2″ of ice on trees, some wind gusts could exacerbate an already bad situation with more downed trees.
° Don’t forget about the cold behind the storm. Single digits are coming! And if you don’t have power…brrr.
° A snow shower or two for Thursday?
° Another storm next weekend? or is it just intermittent numerical hallucinations?
Sorry to keep this short again tonight, so let’s cut to the chase…
This storm has gone sideways in several ways. I love trying to figure it out!
For Raleigh, my current thinking is 2-3″ of sleet/snow (more sleet than snow by far) with an additional 1/2″ of freezing rain. One of the surprises has been the later evolution of the storm… It’s quite possible that we may not see appreciable precipitation begin until late afternoon on Saturday.
At 1/4″ of ice accrual widespread power outages begin. We’re expecting at least double that. Make plans to lose power. Figure out how to stay warm as temps will drop to single digits following the storm. Charge your batteries so they’re ready to power mobile phones.
Again, down the road maybe we have more winter weather to deal with… snow showers on Thursday and another storm for next weekend?
There has been no appreciable change in the thinking for this weekend’s blockbuster winter storm. Confidence continues to grow that this could end up being an historic event for a large swath of the South and Mid-Atlantic, including NC.
Model guidance over the last 24 hours has remained remarkably consistent, advertising a big storm tracking across a huge chunk of real estate, with snow measured in feet on the ‘cold side’ and a crippling ice storm on the ‘warm side’. The cold air is not in question. The remaining uncertainty is in the details of the surface low track and the extent of the mid-level warm nose intrusion. Those two factors will determine what flavor of winter precip ends up in your backyard.
The most important message right now is that this system is loaded with moisture. Liquid equivalent totals across NC are expected to range from 1.0″ to 2.5″. For most of the state, the majority of that precip is expected to fall as something frozen (snow, sleet, graupel) or freeze on contact (freezing rain). So however you slice it, it’s going to be a frozen mess… and a big frozen mess at that.
Again, the surface low track along with the depth and reach of that warm tongue aloft will be the deciding factors. That’s what will separate 2 feet of snow vs 6″ of snow, plus an inch of sleet vs 2″ of ice accrual. At this lead time, it’s honestly foolish to try to nail down p-type totals for any one location. The smart move is to prepare for a prolonged period of impacts, including extended power outages. Stock up on groceries and supplies now so a few days at home is more cozy than chaotic.
Yesterday I mentioned the concern that the anomalously strong high could suppress the storm track too far south and rob us of the crushing winter blow so many are hoping for. Today’s runs have not trended that way, but we’re still 3+ days from game time. The setup is almost too good to be true, but if it verifies, this is the kind of storm people will talk about for a long, long time.
We could be looking at enough snow and ice that cars and trucks simply fail you. Which is why this weekend in Raleigh… the droids are officially joined by a Tauntaun as the preferred mode of transportation!! May the force be with you!
Yesterday’s flakes definitely weren’t what we want. But boy do I have something that will satisfy even the most ravenous snow geese on tap for the weekend!
The impending arctic outbreak over North America has been well-advertised in the long-range numerical guidance for a couple of weeks. Now the likelihood of a major southern snowstorm is all but locked in. The pattern itself is a beautiful setup, and at this juncture basically all the models agree there is a big storm on the way for a large swath of the southern and eastern US. In fact, NC hasn’t seen as great of a setup as this in many, many years. There’s a lot to be excited about.
The timing of the storm is still up for debate, but for now our impacts look to begin overnight Friday, through Saturday and possibly into Sunday AM. The setup is a classic southern-tracking storm that begins in Texas and slides east through the Deep South as it makes its way to NC and possibly the Mid-Atlantic. An arctic airmass arrives behind a cold front that moves through Friday. The moisture arrives shortly after from the west, producing widespread snow, sleet, and freezing rain for much of northern GA, and all of SC, NC, and VA. This will be a strong storm with a lot of available moisture. And since the cold air will be copious, a majority of the precipitation will be something frozen for a large chunk of US real estate.
There is widespread support among the operational deterministic runs, the ensembles, and the AI models. In fact, for a storm several days out, this type of consensus is quite rare. For instance, all but one of the 50 members of the ECWMF ensemble suite has measurable snow at RDU. About 15 of the members print greater than a foot, leaving the ensemble mean around 7″. That’s impressive, and that’s just one modeling suite. All the other majors are in line with this thinking. Of course they have their own variability in timing and p-type distributions, but the generalities are the same.
The other encouraging factor is the good run-to-run consistency. This is not one of those storms the models show in the morning runs only to disappear in the evening runs. We are getting tremendous consistency.
At this point, I personally am making contingency plans for the weekend with the expectation of major disruptions to normal schedules. And yes, there’s still plenty of time to watch, so at this point they are just contingencies. But over the next couple days, you’ll see winter storm watches and advisories go up first in Texas and then spread east to us here in NC.
One other point to make… assuming we do a get several inches of snow, this would be a setup where with even more cold air filtering in behind the storm and a fresh snow pack, we will see morning lows drop to single digits, possibly even close to 0.
What could go wrong? One big thing to be fearful of with these situations is the cold air pushing too far south such that the storm track is suppressed. In those cases, it’s just damn cold and your friends even farther south get the good stuff, leaving us dry and cold with a flurry or two. I’m sure the storm track will vacillate north and south in the models over the next couple days until we focus in the exact track which will inform the distribution of snow to sleet to freezing rain.
This far out, it’s important to not hone in on specifics. Just know that this time around… these are the droids you’re looking for, and they’ll be covered in snow and ice!
Spoiler alert… tomorrow’s setup is one that lacks the cold air necessary for a decent snowfall. The moisture should arrive well before the cold air. So this will be a situation where we’re hoping there’s still enough precipitation remaining by the time the lower-level temperature profile supports snow. Even then, it’s likely that surface temperatures will remain a couple of degrees above freezing until after the precipitation has ended.
What has trended in our favor is an increasing confidence in greater precipitation totals. This is important because higher precipitation rates will help to dynamically cool the elevated above-freezing pockets. So there’s at least a path to some heavy bursts of snow where the column cools to isothermal right around freezing. That’s the good news, if you want snow.
The bad news is surface temps will remain above freezing thru the event. Accumulations will be limited to grassy surfaces and elevated, exposed surfaces. Roads should not be impacted given today’s temps in the 50s.
Models are still all over the place, with some showing several inches and others keeping it mostly rain. Reality is probably closer to rain for much of the event, mixing with and then changing to snow. For Raleigh, that likely means a healthy dusting to maybe 3/4″. Bust potential down is all rain with some flakes mixed in and no accumulation. Bust potential up is we get lucky with a few heavy snow bursts that overwhelm the above-freezing boundary layer, and we could see up to 2″ on grassy surfaces. Not a likely outcome, but not totally off the table yet.
Timeline-wise: light rain breaks out overnight with an initial band, then a lull, then the main precip shield arrives around daybreak. Expect rain through the morning with temps in the low 40s, dropping into the mid 30s by lunchtime. That lunch-to-afternoon window is the best shot for snow in the Raleigh area. Again, the harder it precipitates, the better the odds it flips to accumulating snow. We’ll probably only have a 2–3 hour window to make the most of it.
So… maybe this is the snow that some of you are looking for… pretty coming down, a light blanket of white on the grass and car tops, and no impact on the roads.
Cold air rushes in behind the precip, with temps dropping into the mid 20s overnight. Black ice could be a concern for Monday AM travel.
And while tomorrow is interesting… I’m more intrigued by the possibility of a real winter storm for us in the 25-26th timeframe.
First… it looks like the convection along the Gulf Coast didn’t do too much damage to moisture transport with the developing coastal low. And, the upper level energy sweeping across the state looks to be over performing a bit on general light snow for the state. Many locations across Wake Co. are approaching 2″ as of 4pm with several hours of snow still to go. We’re probably looking at a range of 2-4″ across the county with maybe some lucky 5″ totals in the eastern parts of the county. The heaviest snow axis for the state will run in a line from Wake Co. north and east to the Nashville to Elizabeth City. Again, totals in the northern coastal plain will approach a foot.
Final thought… the GFS (American medium range model) had a handle on this system from the get-go. Props to the GFS. It has been steady on the non-phased, weaker solution from over a week ago. The Euro has consistently superior skill scores the aggregate, but this time the GFS wins. #Merica
P.S. I forgot to mention an addition, quick round of snow showers will swing thru tomorrow (Thursday) morning. It shouldn’t be anything to be concerned over. Just more pretty snow with perhaps a dusting of accumulation. Past that, we’re done with all the winter weather mischief until the first week of March, when things get interesting again.
I thought about this late last night… how will the weakening surface low, heading east over the Gulf coast affect cyclogenesis off our coast? what happens if a ton of big t-storms (MCS) fire in the Gulf (see pretty colors on the satellite pic above)? Will that rob the moisture transport to fuel heavy precip as our storm develops? If so, how much would that reduce the geographical size and magnitude of the precip field?
…because, in Raleigh we’re depending on the storm to develop bigly in order to throw significant moisture=snow this far west.
Hot off the presses… all of this evening’s model guidance is coming in with a downward trend in QPF (liquid equivalent). At this point, we need to think about busting lower than higher. Maybe shave the 2-3″ back 1-2″ for Raleigh and hope to be in a band?
It looks like a nowcasting situation for tomorrow as we monitor the development of the low and radar trends.
To rehash… we’ve gone from expecting a nicely phased, moisture laden system with widespread winter weather to now expecting weakening upper level energy coinciding with the development of a surface low offshore to produce our winter mess. So think of it a two mechanisms that aren’t phased or synergized to realize their potential. Now it looks like the weakening upper level energy and weakening surface low traversing to the east across the Gulf will only be good to produce generally light precipitation for NC. The real potential for significant snow will come from the development of the surface low off the Carolinas’ coast… how far west will dictate how far west the axis of heaviest moisture will punch. In the foothills and western Piedmont, there will be a dry slot that misses most everything, save some flurries and light snow.
The good news is that there will be significant snowfall totals over eastern NC and VA. The trick is nailing down where that axis will be. Much of that intense precipitation will be driven by banding from frontogenesis in a complicated dance between the northward push of the warm air intrusion. It’s a blessing and curse. The warm tongue intrusion enhances the frontogenesis, which drives higher precip rates just to the north, while just to the south the warm air melts the snow aloft and you’re left with a lot of sleet and even farther south, freezing rain. So at this point, we’re rooting for the low to ramp up hard, fast and as far west as it can.
The completely frustrating thing about the evolution over the next day will be the amazing gradients of feast to famine over relatively short distances. It will be typical to see 6-7″ in one place and 1-2″ over a span of just 20-40 miles.
Latest models continue to trend downward with total precipitation farther west. We’ll see how things evolve overnight. For now, best guess for Raleigh would be 2-3″ of mostly snow with some sleet mixed in. If we can get the moisture axis farther west, we could see more. Again, what seems a lock is that areas from Raleigh north and east toward the Tidewater of SE VA will be the winners with 6-12″.
Look for the precip to breakout before lunch. Bust potential low for Raleigh is dusting to 1″; bust potential high would be 5-6″. Then on Thursday midday, there will be another round of snow showers that comes through adding just a dusting.
Here’s hoping I get to use that Eagle Brand milk for snow cream!
What I’m about to say is why, as amazing as the advances in weather prediction have been, you can’t really know with confidence what’s going to happen with a winter storm until you’re staring it in the eyes. Even now, those eyes are beady and shifty. You can’t trust them!
The evolution of the thinking on the storm has covered a lot of ground over the past week. I was very concerned for a crippling ice storm for NC, with a blockbuster Nor’Easter for the I-95 corridor. Then, run by run, we’ve advanced the cold air farther south and consequently the storm track. What looked to be a nicely phased, moisture heavy storm rounding the bend at the Carolinas’ coast for a date with the Northeast, now looks to be a slider that doesn’t really phase and pushes out to sea.
What does this mean for NC? It means that a majority of the precip that falls in Raleigh will be in the form of snow and sleet. And it means that there probably won’t be as much precip as feared. It also appears that northeast NC and southeast VA could hit the jackpot for most impressive snow totals.
Remember when the trend was our friend? We’re at the point now when the trend needs to stop trending and do a little snap back. Because if we keep on the trend, the slider is going to keep slip sliding away. Now that we’re in the short term modeling window, hopefully there will be more clarity as we build consensus on this solution which produces widespread light to moderate snow over the northern half of NC, a transition zone to sleet and freezing rain just south of there, and the snow sweet spot in northeastern NC with totals approaching 10″. This is the best guess for now, but there is plenty of window left for a scenario that has the low strength closer to the coast, which would throw the heavier snow bands farther west to Raleigh. All in all, it’s not really bad news. It’s just the difference between a colossal burger and a slider.
Models still insist on precip breaking out in the Triangle late morning on Wednesday. I still wonder if daybreak might be a better estimate. We shall see. I know it seems obvious to say, but we should have more confidence in all aspects of the storm by early tomorrow afternoon. At that point, the storm will be taking shape over the Central Plains and maybe those beady eyes won’t be so shifty!
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