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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.

Enjoy your snow cream!

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!

This week, a major winter storm will affect a large chunk of real estate from Missouri to Tennessee thru the Carolinas up the coast thru the Mid-Atlantic and perhaps into the Northeast. NC appears to be destined for a week of disruptive weather.

We begin the excitement tomorrow with the passage of a strong cold front. In addition to more rain and thunderstorms, some of which will be heavy, there will likely be a period of several hours where winds will gust from 35-55mph. This will be problematic for saturated soils from days of rain. Expect downed trees that will leave thousands around the state without power. Enjoy a brief rain-soaked tag of the 60s because behind the front WNW winds will usher in much colder, drier air.

Then, we turn our attention to the headliner for midweek. To reiterate, this will be a major disruptive storm for much of NC. There will be a lot of precip. The question will be what the recipe is for the makeup of frozen stuff in your backyard. All the modeling points to storm total QPFs (liquid equivalent) of a minimum of 1″ across the state. So whether it’s all snow (unlikely at this point for Wake Co) or a mixed bag of snow, sleet and freezing rain or all freezing rain… these are all bad scenarios if you don’t like winter weather.

Still 3-4 days away, there is much detail to suss out. There is agreement that surface temps will be solidly below freezing. Uncertainty creeps in as to the extent of the mid-level warm air surge. This will dictate the ratio of snow to sleet to freezing rain.

The Euro has been consistent in its favoring of predominantly ice until today’s midday run. It was significantly colder and more suppressed with the storm track today, resulting in more snow and sleet in combination with the freezing rain. As hackneyed as it is… the ‘trend is your friend’. So, we’ll see if this is a trend or a wobble.

A word about timing… now, consensus is that precip begins Wednesday AM. Many times, though, once we transition from mid to short range horizons, timelines trend earlier. Over the next couple days, I will be looking for the possibility of precipitation beginning as early as late Tuesday evening. Regardless, the duration for accumulating frozen precipitation should be 10-12hrs.

Key Points:

1 — Potential problematic gusting winds above 50mph on Sunday with periods of heavy rain and a thunderstorm

2 — A major winter storm will impact NC on Wednesday. Regardless of the version of wintry precip we receive (snow vs. sleet vs freezing rain), storm totals will cause widespread travel and potential power outages related to downed trees and power lines. The green light to buy the requisite bread and milk looks to be coming soon!

For the past couple days I’ve been very good not to hype next week’s pattern. Now comes the time to begin evaluating the possibilities for frozen fun.

A couple of things to note:

1 – Overnight Saturday into early Sunday morning will bring the chance for wind gusts from 35-50 mph. Given the excessive rain we’ve had, the soil is loose, so the possibility for downed trees and power lines needs to be considered.

2 – At a week out (targeting the middle of next week), there is still a lot of run-to-run variability as to the track of a southern storm in all global models. What we can say is that all the models show the storm and the signal in the ensembles continues to amp up. The track will decide the precip-type, and until the model’s converge on a solution for that, we’re just hand-waving and conjecturing.

Key point for now is that a winter storm for the NC and VA appears likely. We’ll know more about who gets 35° rain vs. ice vs. snow early next week. Let the snow dance begin!

The 18Z NAM, hot off the presses, has come in trending bullish for tonight’s event. It basically adds an additional .1 to .15″ of QPF (liquid equivalent) across our area on the western periphery of the precipitation shield compared to previous runs (and with even higher totals down east.) So, it seems the westward trend continues. And while it is difficult to know if this is just a bobble that will settle back with the next run, it is worth noting that upstream snow totals along the Gulf Coast, as well as the northern extent of the precipitation axis have both generally overachieved.

I’ll continue to monitor the latest to see if this translates into that bust potential to the high end. Remember also that this will be will be a dry snow with snow to liquid equivalent ratios running higher than the 10:1 rule-of-thumb. That fact could also help fluff up totals. We’ll see if we have to bump up these numbers later this evening.

Snow should begin in Wake Co. in the 6-7pm timeframe this evening. Snow will begin lightly and increase to steady thru the evening. Snow should end by midnight or 1am tonight.

There is no real change to the thinking. This event will favor highest totals in the coastal plain with waning totals as you head westward. There will probably be a large swath of flurries to a dusting throughout NC. The line for measurable snow will run along a SW to NE axis from Charlotte to Chapel Hill to South Hill, VA. In Raleigh, I’m expecting 1 to 2″ …again with that west to east gradient. So even across Wake Co., you’re more likely to get 1″ at RDU and 2+” in Wendell.

For Raleigh, my forecast is just under 2″. Bust potential to the low side is .5″. Bust potential to the high side is 3″. Regardless of the total, it is very cold and will remain so. Lows will be in the teens tonight after the snow departs. Tomorrow we won’t get above freezing. The sun will help with melting, but again with the air temperature still below freezing and going down to the low to mid teens by Thursday AM, there will still be travel headaches, especially on the secondary roads.

Obviously, this is not the big one for Raleigh, but head down East if you’d like to experience a fairly wide swath of 3-5″ snows with lucky winners that may achieve over 6″. As you get closer to the coast, sleet mixing in will reduce those totals.

Enjoy whatever you get. After this round, we should get a reprieve from the cold with temperatures rebounding to seasonal norms by the weekend.

Last time we left off with… “It will be feast or famine snow <for Wake Co>”

Maybe though, even as the 100 miles didn’t seem to go in our favor in the past 36 hours’ model runs, tonight, we may be converging on a solution that will at least serve appetizers!

At this point, (emphasizing higher totals from east to west) a middle-of-the-road guess for Raleigh is probably 1/3 to an 1 inch. Important to note is that all models are now trending westward with the moisture field. Tonight’s 0Z models depict a significant bump westward. We’ll see if the trend continues or if that progress stalls. Just to tease, but still on the table is 3+” if, if and if.

I’ll update tomorrow after the 12Z model suite comes in.

Let’s go Snow(Pack)!

Several days ago we knew it was going to be cold and thought there might be a Deep South snowstorm.

Tonight we know it’s going to be cold and we know there’s going to be a Deep South snowstorm.

Now, there’s JUST ONE THING we need to know. The question that remains is what the track of the storm will be. Obviously, the track determines the moisture axis and where the wintry precip falls. We’ve seen fewer Miller-A setups in recent years, and this time around, the high pressure will be quite strong in pushing a very cold airmass quite far south. Just how strong it ends up being will help determine how suppressed the storm track will be. And when we’re talking about snow to the entire Gulf coastline… that’s suppressed.

I expect the ensembles to converge on a consensus track tomorrow… (even as the last couple runs of the GFS want to go for two smaller storms rather than one). So until then, we’re really just pretending if we say we know the track more than within a couple hundred miles. And a couple hundred miles variance for Wake Co. will be the difference between a dusting and 10+” of snow.

To sum it up for now… ‘warm’ rain tomorrow, maybe a lucky snow shower later, north… probably not. Cold air rushes in tomorrow night and highs on MLK Day sill struggle to reach 30°. Moisture enters the area Tuesday evening and depending the storm track, it will be feast or famine snow!