NC/VA Sunday Snow Threat

[WeatherNC]

I guess I'm not yet seeing any big forecast changes at all, let alone in a short time.

James was referring to the afternoon disco which painted this a "non-event" for the entire CWA. Evening HWO coming in with "advisories may be needed." Granted, while not as bad as MHX waiting for 3" on the ground to go from zero to warning, a sig shift in the realm of "Big Brothers" thinking, at-least as we know it.

[Bozart]

its the change in their forecast discussion.... very different from earlier in the day

Yeah, and actual forecast changes may come, too "once the new data can be analyzed," as they said. I'm patient.

[WeatherNC]

I guess this fits the bill as a discrepancy in the 0z American guidance...

one is going to be wrong, or do you split the bill which would not be half bad?

[NCSNOW]

Thanks weather NC. Check out what the oz gfs just spit out. Complete turn around for day 8 with rain.

[MillzPirate]

unfortunately, I feel the closer reality will be the GFS output... just think the NAM is way too wet. However since the GFS was revamped it has shown a dry tendency on the east side of the mountains

[WeatherNC]

0z rgem, Canadian high res regional model, has continuity with it's 12z run in showing two areas of precip working through. Amounts look heavier than the GFS, but not sure if they are as much as the NAM, although placement is very similar. you can toggle through the whole loop from the link below

Round 1 nearing the coast around 0z

Round 2 nearing the coast around 6z

http://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html

as with the 12z run, there are a couple heavier QPF panels in there

[MillzPirate]

if my metrics conversions are any good... RGEM looks like .35-.40 for PGV

[MillzPirate]

one thing to note is the GFS paints a .5 strip for the system all the way until it reaches the lee side of the mountains. I honestly believe it is overdoing the downslope a bit and not handling the coastal development well. Which is supported by the higher res models in the NAM and RGEM

[griteater]

RAH AFD

An upper level vorticity forecast track over or near the southern Piedmont of NC favors the northern Piedmont for snow.

This matches with what I've always thought about these types of systems in that you do NOT want to be south of the 500 mb vort max to get any noteworthy snow, both from a temp and precip standpoint. East of the mountains in the piedmont and coastal plain, I see the best location for accumulating snow (dusting to 1 inch, isolated 2 inches) to be, in the NE corner of the state, along a line from Raleigh to the coast, and north of there to / along the VA border. In and around the Triad area, surface temps will be a major concern for accumulating snow. Sfc temps above freezing during the daytime hours are very problematic for accumulating snow without heavy, heavy snow, which has to be a long shot with this system. In contrast, the bulk of the snow in the aforementioned NE portion of the state will occur after the daylight hours and with temperatures dropping closer to freezing - both of which will make a huge difference with respect to getting some light accumulations.

[eyewall]

Wow I come back and RAH has flipped on their call! I was expecting the worst. I will have to look at the data and see if I can stick with mine or not.

[superjames1992]

James was referring to the afternoon disco which painted this a "non-event" for the entire CWA. Evening HWO coming in with "advisories may be needed." Granted, while not as bad as MHX waiting for 3" on the ground to go from zero to warning, a sig shift in the realm of "Big Brothers" thinking, at-least as we know it.

Yep.

Yeah, and actual forecast changes may come, too "once the new data can be analyzed," as they said. I'm patient.

And they have!

Saturday: Rain and snow likely after 4pm. Mostly cloudy, with a high near 44. Light and variable wind. Chance of precipitation is 70%. Little or no snow accumulation expected.

Saturday Night: Rain and snow likely before 11pm, then a slight chance of snow between 11pm and 2am. Cloudy, then gradually becoming partly cloudy, with a low around 30. Calm wind becoming north between 4 and 7 mph. Chance of precipitation is 70%. New snow accumulation of less than a half inch possible.

They're still not forecasting much of anything, but a coating is better than nothing! A coating will make a nice wintry scene to kickoff meteorological winter!

[CAD_Wedge_NC]

I do realize that we are still 20 hours out with this system, but looking at radar trends upstream, it looks to miss this area to the east. What we want to happen is for the system to track to our west / south and then slow down. If a coastal low does develop, it looks to be too far east right now to do much for western NC (outside the mtns). Of course, anything can change, but we are getting to the timeframe where trends are small. What is interesting to me is that the qpf totals are increasing with each model run. Usually with clippers, we see a drying trend as we approach the event. I will not jump on the NAM train just yet, but I do think this model may be seeing things a little more clearly than the GFS at this range.

I agree with some previous statements. The best area right now, outside the mtns, looks to be in eastern NC. Wouldn't be surprised to see advisories going up for some areas down that way tomorrow if qpf holds serve or increases with later runs. Bottom line...... it's rather unusual to be tracking a system this early in the game here in the SE and past history tells us not to expect much with this type of setup.

[phil882]

For what its worth, both of the regional WRF models on NCEP are coming in quite bullish on total precip for the clipper. Take a look:

In addition, the SREF model mean for the last three runs has come in more bullish on precip. at each time interval. Check out the evolution From 09z to 21z runs today. Certainly a trend in the right direction.

[MillzPirate]

all the high res models are pointing to higher precip totals. if those values proved to be correct however, it would be short notice time for advisories/warnings across NC

[WidreMann]

Those hi-res models are always bullish on precip. I wouldn't trust them as far as I could throw them.

[Jon]

WRAL is having a contest: http://wral5.upickem.net/engine/Welcome.aspx?contestid=24329

Entries need to be in 24 hours before the snowfall, so submit tonight!

[eyewall]

Updated call map:

[phil882]

Those hi-res models are always bullish on precip. I wouldn't trust them as far as I could throw them.

As a whole though, guidance has trended upward with precipitation totals compared to this time yesterday. I am hypothesizing that a lot of this has to do with the unexpected development of a weak secondary jet max that could be helping to improve divergence in the region ahead of our clipper. Dual jet structures can be quite effective for precipitation production.

[WidreMann]

Doesn't matter if BL temps are too warm, which they will be.

[MillzPirate]

Doesn't matter if BL temps are too warm, which they will be.

wouldnt be a winter without the worlds most pessimistic board poster, WildreMan

[WidreMann]

wouldnt be a winter without the worlds most pessimistic board poster, WildreMan

What was your old name?

[MillzPirate]

What was your old name?

MillzCast

[WidreMann]

MillzCast

I have no memory of you.

[MillzPirate]

I have no memory of you.

that is unfortunate for you. I posted on eastern for several years

[phil882]

Doesn't matter if BL temps are too warm, which they will be.

I think the issue of Boundary Layer temperatures is really getting overblown for this system. As most people know, the sun heats the ground, which is turn heat the air near the surface of boundary layer. However, one important factor to note is that the sun angle is actually much lower during this part of the year than it is during late February and early March. In addition, we seem to have ample cold air aloft beyond 900mb and thus, once the precipitation starts things will quickly become isothermal from 900mb below to the surface. Finally, the precipitation is moving in in the late afternoon and early evening. While we still have some sun to contend with, this is a much better situation than a mid-day sun angle and things should improve as we progress further into the evening.

If this doesn't make you feel better, take a look at the latest BUFKIT soundings for KRDU from the 00z NAM. Despite a very warm surface temperature initially (44 degrees!), it only takes about an hour of diabatic cooling to create an isothermal snow sounding in the area. I think the biggest thing to watch won't actually be temperatures, but how much precipitation will be popping up on the radar. If we get close to the amounts that NAM and the higher res WRF models are showing, we should have ample dynamical cooling to get wet snow across eastern North Carolina.

[DCMetroWinston]

wake up everyone! we are in the middle of operation snowcast!

[Gastonwxman]

The precip is on the move and ready to hit the Apps. Let's see how it evolves.

http://www.intellicast.com/National/Radar/Current.aspx?animate=true

[DaculaWeather]

Sugar Grove NC, 27.6 and snow Webcam

http://www.daculawea...lina_master.php Drag the map so you can see the NW side better.

[MountainMarvel]

Snow has arrived in Rutherford County! During the past two hours, short bursts of snow have been falling. The temp is at 29 degrees and the clouds have really moved in here. These pics were made about an hour ago IMBY. Pretty cool!

Small crystals, but snow just the same....

[Cyclonicjunkie]

Updated call map:

Great job