Big storm for the US the next 2 days, what does it mean for NC?

A monster of a storm is starting to take shape today on through Thursday. With snow,ice and severe weather for a big chunk of the central and eastern US. But Ill focus on central NC here and give you an idea of whats to come. Fist heres the set up for the massive storm (more like a classic early spring storm)

This is Tomorrows set up from down right Blizzard conditions to spring like severe weather and in the middle a dangerous icy mix with ice amounts possible up to 1''in thats crippling. But here in central NC for today and tomorrow we'll see cool cloudy weather, Although there maybe some light freezing drizzle in parts of north and north west NC tonight into tomorrow morning so watch for that. Now heres a computer model forecast for Wednesday morning showing NC in the warm sector with rain and a few thunderstorms are possible aswell.

That first red line you see just under the blue is the 10c line OR 50F degree line with the 2ed red line the 68F line so you can see warm moist air being pulled up into NC with a few storms possible, Ill keep watch on this as any storm in this set could be severe, but right now not looking for a big severe wx out break in NC. The deep south will endure a severe wx outbreak though. Now what we have going on today and tomorrow is called Cold Air Damming. When the cold air dams up the eastern side of the mountains. As Tuesday night comes are winds will shift out of the south/south west with the warm font approaching. Wednesday should be rain and possible storms in the morning hours followed by warm breezy conditions later in the day.  

Big spread in next weeks storm, among the models

Nice weekend coming up from Friday on into Sunday really, although Saturday will take the cake for a while it looks like as the models really are having a hard time for next weeks system heres what I mean. We'll first look at the GFS for Tuesday evening.

Thats valid on next Tuesday evening, over all showing a storm system in the Gulf starting up. But as me move on the the Canadian model it shows something different, really showing an ice set up.

 
See those two lows in red and that blue line, that blue line shows cold air damming (CAD) on the eastern side of the mountains with low shallow cold air at the surface and if cold enough can cause ice and i can tell you now the surface temps from the CMC show us below freezing. But lets look at the upper levels to get a better idea, after all what happens up above causes what happens at the surface.

This is the GFS upper level chart for Tuesday evening and it shows a few pieces of energy, but the one causing the surface low in the Gulf is the short/wave over TX. Now lets look at the CMC upper level chart.

See same time, but its faster with the short/wave and its now going negative tilt(shown in white over TN) also in red is the ridge out west and thats needed to help dive this energy more south.  One last model to get an idea is the Euro model and I must say its flip flopped big time from yesterdays run (like a fish outa water)

Its more inline with the GFS (albit slower) also the EC upper level chart

see the main short/wave is in TX just like the GFS and a good ridge out west. And the EC on Weds evening showing a bit of a wintry set up.

  But wait dont get too happy just yet, as these are just operational models, meaning we look at these first then we look at whats called the Ensemble members or the means (average) so lets look at those real quick
First the GFS

This is Weds evening GFS mean, compare to the EC mean

Look at this the Low on Wednesday evening is up north not south and east like the OP EC.

Heres the CMC mean run Weds evening and its head strong on a double barrel low or (Miller B) set up. So with all this said you can see there is a lot of model runs we must go through before can be have a better idea for next week and I am in no way saying its going to snow, or an Ice storm is coming Im NOT going with that just yet right Now I will keep things below normal on temps in the low to mid 40s Tues-Wed and possible rain(or even rain/snow mix Wed), of course as time get closer I will update this but thats it for today Ill be spending time with my family again Fri-Sun so look for another post Sunday evening.

Unexpected Thunderstorms this morning, explained!

Well some of you may have heard some rumbles of thunder this morning across western/central NC. This was some unexpected storms that developed under an upper level low that has very cold air aloft and while the surface was very cool with temps in the mid to upper 30s, about 5000ft aloft there was some instability. Ill explain how this happened. First take a look at the image below, its called a upper air sounding.

(click to enlarge) what this is, is a profile (vertical profile of the atmosphere) and the red line is the temp from the surface to the top, and the green line is the dew point. Now the dark red dotted line shows a parcel of air as the air temp and you see where the temp line (red) and the dark dotted line separate. That shows instability in the atmosphere known as CAPE. and there was just enough of it this morning above the surface to develop some lightning. Heres the lightning image from this morning about 8am or a little after not sure of the time.

see some good amount of lightning in western NC. Next is the NAM analysis from 7am this morning about the time the storms were developing.

First image is the 700mb forcing, or upward motion in the air getting these storms going. The 2ed image is the upper level moisture and the black lines shows instability and you can see right over central NC there was some at that time.

This is the radar image about 10am this morning and you can see the line of storms just right of the 2ed low over western NC. A few radar and sat images from this morning in case you missed it.

Visible sat image of the storms tops this morning. Just wanted to write about this as its rare to have storms while the surface is so cool and stable, but when an upper level low is coming anything can happen.

Mostly rain event for central NC, but a few snow flakes possible at the end.

Well as the title says this will be a mostly rain event for most of NC, all but the mountains. Now I want to focus on the potential for some snow on the back side of this as the upper level low swings by over head tomorrow evening. To help me I have a few images here from the latest forecast models. 
First heres the GFS valid tomorrow evening as the main surface low pulls away showing some possible snow to end the event.

That blue line is roughly the rain snow line and most of the time anything falling on the left side of the blue line could be some snow.
Next is the Euro and Canadian models.

That area outlined in white is area where snow is possible as the system pulls away.
Now after looking at the 3 main globe models lets take a closer look at the regional models with a bit higher resolution. And first up is the NAM

Valid tomorrow evening and that red line is the freezing line at about 5000ft good place to look for rain vs snow. Also the NAM precip type would indicate a few flakes to end as you can see painted by the blue over the Triad of NC.

Heres what the NAM puts out for snow accumulations (although I dont expect much UNLESS it snows hard enough)

Again this I believe would only happen if it were to snow hard and overcome the warm surface.
Now to go down the our real Hi Res model the WRF model and it does pretty good although it can sometimes be way off but its always worth giving a look.

 

the WRF also shows this ending as rain mixed with snow. One last map I want to show from Matthew East from News14 Carolina this is his snowfall map he put out today and not expecting much for the Triad BUT still snow is possible to fall tomorrow evening.

Now after showing all the models and such, This will be a mostly rain event for most of NC outside the mountains. But as the upper level low comes by overhead tomorrow evening I believe the chance is there for some snow to fall over the area, But if this upper low were to shift from this forecast track then that could mean the difference between seeing snow or not so this is really a down to the min forecast and tricky at that but we will see as tomorrow draws closer.

Sunday afternoon update on storm next week.

Well latest models are in from both the over night runs and morning runs and, sadly if your a snow lover this is NOT what we want to see. A more westward shift in the forecast storm track so this means more in the way of rain, with perhaps rain changing over to and ending as some snow (still not set in stone) but looking more likely.
Heres a few forecast model images to give you an idea of how things are looking.
First model is the GFS on Wed morning (after a mostly all rain event Tuesday and Tues night)

That dark blue line is the rain/snow line at about 5000ft. And mostly for us here in Central NC a rain event but if we go to 12 hrs later Wed evening on the GFS we can see this ending as some snow here.

Next is the ECMWF (European model) and its pretty much in line with the GFS on the storm track with maybe some snow to end the event.

Now I dont have a 6 or 12hr interval of the EC model only 24hrs and the next image would show the low up in New England but I do know the EC shows it ending as some snow for western/Central NC.
And the Canadian model is WAYYY to far west for any chance of snow.

and it shows an all rain event, and thats not out of the question either but most of us are leaning with the GFS/EC and so is the HPC and heres their forecast map for the track of the low Wed.

Its more of a blend of the GFS and EC. So snow is not totally out of the question YET but this will be watched for either way to go. Looking ahead after this storm we may get a quick warm up here in NC heres a forecast highs for Saturday around Central NC.

Maybe some upper 40s to low 50s not bad in my book, one last thing I want to show is the 8-10day mean of the upper air flow from the EC and GFS.

Still cold is looking to be the main thing for the next couple of weeks to come, at least the AO and NAO is going positive later on, and what that means is at least no major blocking over Greenland (at least the west side) to keep the cold locked in so it will be more cold in and then moderate after a few days.

Cold weather to stay, maybe some more winter weather down the road??

Well we have had a nice few days from the real cold with highs Wed and Thurs getting into the 50s and upper 40s, compare that to where we have been most of the winter and thats warm but upper 40s is really our normal. Not so fast though all my warm weather friends more cold is in store, along with the POSSIBILITY of wintry weather. Heres what I mean take a look at this image on the left is the EC (Euro) model and on the right is the GFS (US) model.

This is the 10day mean, and you can see that big ridge out west keeping warmth in the west and a arctic flow out of the NW into the east/se US. Now the blue lines I have drawn show areas of troughs that can produce upper lvl energy needed to combine with cold air from the north to produce winter storms in the eastern/se US.
Now lets take a look at the GFS week 1 ending temps, (this is the mean departure from normal)

On this the real brutal cold will stay up in the NE and New England, BUT that does not mean us here in the south will get off, in fact arctic air is set to invade starting Friday into early next week as another southern system may produce wintry weather here in NC but thats a another story Ill have later.

And then we take a look at week 2 ending Feb 3rd mean temp departures and, yes more cold to stick around.

Well thats it at this time Im leaving town tonight but should be back Sunday evening to post an update on our possible storm.

Wednesday night/early Thursday morning update for wintry weather next week.

Well the evening models are in and while there remains some differences one thing still remains, and thats the possibility for some type of winter weather here in central NC early next week.
Now I have some images here to help you better understand what were looking at.
Heres the 00z Jan 20th new model run for Monday afternoon around 1pm showing strong cold air damming in central western NC on this surface chart.

Next image is the 850mb (5000ft freezing line is good for snow rain to snow line) and at that time its in the southern Piedmont of NC.

So we would have to watch to see how far north that gets before a change over to freezing rain or rain.
Now the CMC(Canadian) model is a little less with any snow and showing more freezing rain to rain set up.

Not to mention its slower than the GFS, and that may be a trend a slower solution may mean less snow and more ice/to rain for central NC. And heres the ECMWF model Mon evening.

Good CAD (cold air damming) but have to watch that 850 warm front. But by Tuesday evening even the EC goes over to rain/freezing rain, so as I said still lots of time to watch this possible storm but Ill keep you updated on the latest.
I do want to note though from tomorrow evening (Thursday-Sunday) I will be out of town but I will post when I have the time but Ill make sure to be back Sunday evening to update you all and thanks for reading.   

Wintry weather early next week???

Well for a while now the models have been hinting at some possible wintry weather early next week around the Mon-Tuesday time frame. But I dont think this will be an all snow event its looking more likely that it will be a mixed event with snow,freezing rain, then rain. Here are some forecast Skew-T charts(shows the atmospheric profile) showing snow to start then to freezing rain then rain first up some images from the ECMWF model (from Accuweather Pro.com)

this temp profile shows mostly all snow to start the event along with the GFS model below.(same time Monday evening)

same thing mostly snow. But as we go on 12 hours later to Tuesday morning both EC and GFS show more freezing rain with a 850mb warm front but surface temps stay below freezing.

GFS

And later forecast soundings show surface temps warming to just above freezing, BUT this is still days out and a strong high in the NE in a good area to keep some low level cold air in we'll see if we make it above the 32 mark.

EC model showing Tuesday morning setup.
Thats all for now Ill have more as this possible event draws closer.

Warmth OR cold

While finally the NAO has gone + leading to some milder air for parts of the east/south east, and the AO had briefly went to neutral (as seen below) the MONSTER PNA staying + will pretty much cancel out the NAO and AO warming effects on the east.

It seems we just cant get a break from this relentless cold (well here in my area we have had a 50F day or two so thats a plus) but still it looks like more arctic air is on its way this weekend.
Sat morning

Thats some cold stuff for me anyway and the NE looks to get into some single# once again, BUT good news for me at least is the NAO does not look to be west based for a prolonged time frame so cold air will move into the SE/MA then after a few days some moderation at the very least in temps, or at least it would SEEM that way with no good west based -NAO still the cold will stick around thanks to our big +PNA ridge and the ensembles of the models show this too, so much for any warm ups, also maybe some more snow storms for the east???