December 14th and onward discussion thread

[Lookout]

lol the 06z run was a lot wetter and the 12z is a lot drier and warmer. Got to love the gfs.

[FoothillsNC]

the euro today looks completely out to lunch on low level temps for this event, especially as you get out toward Wednesday and Thursday. But it also has precip coming northeast from the lower Miss. Valley, which is going to be an icy mess in parts of Tenn and the Carolinas and probably northern Georgia and Alabama as well. The GFS handled the cold a lot better with this wave (and the 2 big outbreaks last season) esp. on the 2m temps. It's overall 5H pattern is similar, just having problems with the cold air, imo. So, theres still freezing precip to be possible in the Southeast and Tenn Valley by Wednesday and Thursday. Beyond tht, i'm sure all models are having a hard time where the thermal gradient is going to be . Very wild blocking pattern and we just don't see this 5H look very often.

[SBUWX23]

the euro today looks completely out to lunch on low level temps for this event, especially as you get out toward Wednesday and Thursday. But it also has precip coming northeast from the lower Miss. Valley, which is going to be an icy mess in parts of Tenn and the Carolinas and probably northern Georgia and Alabama as well. The GFS handled the cold a lot better with this wave (and the 2 big outbreaks last season) esp. on the 2m temps. It's overall 5H pattern is similar, just having problems with the cold air, imo. So, theres still freezing precip to be possible in the Southeast and Tenn Valley by Wednesday and Thursday. Beyond tht, i'm sure all models are having a hard time where the thermal gradient is going to be . Very wild blocking pattern and we just don't see this 5H look very often.

How are 2m temps on Monday and Tuesday? I dont have access to them from my location.

[FoothillsNC]

How are 2m temps on Monday and Tuesday? I dont have access to them from my location.

They aren't as cold in the Southeast, looked about the same as what happened with the last coldwave. Its been back and forth on the 2m temps a lot , and even though its 5h looks similar to GFS it's ho-hum on the surface cold. On 18Z Mon for example , has the 32 line from GSO to ATL and just west of there has 30 line from HKY to Gainesville GA. Has coastal NC in the low 40s at that time. And by 18 Z Tuesday, has coastal NC in mid to upper 30's. With that strong vortex located in a perfect spot to really freeze eastern NC, looks just too warm to me, esp since it has -12 at 850 there. GFS won hands down last wave.

[beanskip]

the euro today looks completely out to lunch on low level temps for this event, especially as you get out toward Wednesday and Thursday. But it also has precip coming northeast from the lower Miss. Valley, which is going to be an icy mess in parts of Tenn and the Carolinas and probably northern Georgia and Alabama as well. The GFS handled the cold a lot better with this wave (and the 2 big outbreaks last season) esp. on the 2m temps. It's overall 5H pattern is similar, just having problems with the cold air, imo. So, theres still freezing precip to be possible in the Southeast and Tenn Valley by Wednesday and Thursday. Beyond tht, i'm sure all models are having a hard time where the thermal gradient is going to be . Very wild blocking pattern and we just don't see this 5H look very often.

Yeah -- that blocking in the 8-10 day time frame of the 12z Euro is like nothing I've seen before.

[SBUWX23]

They aren't as cold in the Southeast, looked about the same as what happened with the last coldwave. Its been back and forth on the 2m temps a lot , and even though its 5h looks similar to GFS it's ho-hum on the surface cold. On 18Z Mon for example , has the 32 line from GSO to ATL and just west of there has 30 line from HKY to Gainesville GA. Has coastal NC in the low 40s at that time. And by 18 Z Tuesday, has coastal NC in mid to upper 30's. With that strong vortex located in a perfect spot to really freeze eastern NC, looks just too warm to me, esp since it has -12 at 850 there. GFS won hands down last wave.

I am starting to wonder if this may be more accurate. Maybe I am just skewing myself towards the Euro but with WNW flow maybe downsloping is going to offset cold advection enough to keep temperatures from staying below freezing as much as we first thought.

[Cold Rain]

I am starting to wonder if this may be more accurate. Maybe I am just skewing myself towards the Euro but with WNW flow maybe downsloping is going to offset cold advection enough to keep temperatures from staying below freezing as much as we first thought.

This is why I personally don't have any issues whatsoever with NWS offices not forecasting extreme/record-breaking cold 5-7 days in advance. Although we all agree that the potential is there for extreme cold next week, the models have been and continue to be all over the place with the placement of the vortex and the depth and duration and orientation of the subsequent trough. I think enough evidence has been there to forecast highs in the 30s for that advance time period, but for them to put numbers in the 20s for highs would have been foolhearty...at least until we get within 48-72 hrs of the event.

Models never seem to get more extreme with the event as you approach the time of the event. They always seem to go the other way. I often wonder why that is the case. But the fact is, you rarely see something whether it's a storm, cold, heat wave, severe parameters, etc. increase in severity as the actual event approaches. It's kind of one of the suckiest things about being a weather enthusiast. The most exciting, extreme weather is always 5 days away on a forecast panel.

[FoothillsNC]

I am starting to wonder if this may be more accurate. Maybe I am just skewing myself towards the Euro but with WNW flow maybe downsloping is going to offset cold advection enough to keep temperatures from staying below freezing as much as we first thought.

the northwest flow downsloping is already factored in. In last years 2 outbreaks, one in early Jan and one in Feb, the euro had my area (which is in great downslope country) about 6 degrees warmer at the surface, than GFS. Same for this past event last week. Turns out the GFS was extremely accurate in all 3 cases here. I can't say for other areas, didn't really scour the entire southeast obs but if memory is right, think the GFS was very in the ballpark everywhere. Right now, i'd go a blend since there is quite a discrepancy, the GFS looks a smidge too cold to me and the ECMWF not quite cold enough, but honestly I'd lean toward GFS. The nighttime lows are going to be a function of radiation, I wouldn't trust those from any model. depends on if you get into good radiation, and this one doesnt' appear to be anywhere really that good of radiation.

[SBUWX23]

This is why I personally don't have any issues whatsoever with NWS offices not forecasting extreme/record-breaking cold 5-7 days in advance. Although we all agree that the potential is there for extreme cold next week, the models have been and continue to be all over the place with the placement of the vortex and the depth and duration and orientation of the subsequent trough. I think enough evidence has been there to forecast highs in the 30s for that advance time period, but for them to put numbers in the 20s for highs would have been foolhearty...at least until we get within 48-72 hrs of the event.

Models never seem to get more extreme with the event as you approach the time of the event. They always seem to go the other way. I often wonder why that is the case. But the fact is, you rarely see something whether it's a storm, cold, heat wave, severe parameters, etc. increase in severity as the actual event approaches. It's kind of one of the suckiest things about being a weather enthusiast. The most exciting, extreme weather is always 5 days away on a forecast panel.

Yeah I agree with some of what you mention but the 850 temps have not really changed much over NC, in fact they are downright cold for this time of year so its not certain as to why the surface gets so warm when unlike the past wave, 850 temps are colder.

[FoothillsNC]

This is why I personally don't have any issues whatsoever with NWS offices not forecasting extreme/record-breaking cold 5-7 days in advance. Although we all agree that the potential is there for extreme cold next week, the models have been and continue to be all over the place with the placement of the vortex and the depth and duration and orientation of the subsequent trough. I think enough evidence has been there to forecast highs in the 30s for that advance time period, but for them to put numbers in the 20s for highs would have been foolhearty...at least until we get within 48-72 hrs of the event.

Models never seem to get more extreme with the event as you approach the time of the event. They always seem to go the other way. I often wonder why that is the case. But the fact is, you rarely see something whether it's a storm, cold, heat wave, severe parameters, etc. increase in severity as the actual event approaches. It's kind of one of the suckiest things about being a weather enthusiast. The most exciting, extreme weather is always 5 days away on a forecast panel.

Extreme events have happened a lot and I mean a LOT in the Southeast over the last few years. Its the "average" we can 't seem to get much of anymore. Hottest summer in "recorded history", Coldest Winter in 30 years. Big time record snows in Apps. Floods in GA, eastern Carolinas. Drought never ending in SC. Its all been pretty well forecast I think., depends on which forecaster your using I guess. And the heatwaves and coldwaves are seen from quite a distance away usually. The biggest part is figuring the degree to go extreme.

[WhiteoutWX]

I would definately be worried about a north trend with the overrunning event next week. Seems thats what usually happens with these types of events. The block seems to be retreating/breaking down pretty fast on the models as the event gets underway. Looks like there is actually alot of room for northward movement, much like the 12z euro shows. Id really like to see that block locked in to get excited this far out. I agree surface cold will be tough to dislodge.

[NEGa]

LOL - this is a snippet from gsp i just saw. too funny

Wednesday night through Friday will feature one of those confounding

nuisance type events that we occasionally see in winter whereby a

weak southern stream wave will come across the southern tier quickly with

enough forcing and moisture for some light precipitation. Timing is always

an issue with these things. The GFS has the weak system coming in

Wednesday night and Thursday while the European model (ecmwf) is about 24 hours

later. Have played this one right along with HPC. The problem is...

of course...low level thicknesses and cool temperatures suggest a mixed

ptype problem if the precipitation can begin during the early morning hours

on Thursday. Followed along with the min temperatures from HPC and in order

to stay consistent...this means a low end chance of freezing rain

early Thursday morning. At this point...confidence remains low

enough so as to not get excited about it. This could actually happen

on Friday if the European model (ecmwf) timing is more accurate.

[dsaur]

Don't think we can discount how cold the ground is for Dec events. Even today, working in my shirtsleeves I am surprised at how cold my feet are. It is just as bad as yesterday. This is a persistent cold, and possibly more coming. I'm content to see a very cold rain forecast for my area, and I'll take my chances. T

[Cold Rain]

Yeah I agree with some of what you mention but the 850 temps have not really changed much over NC, in fact they are downright cold for this time of year so its not certain as to why the surface gets so warm when unlike the past wave, 850 temps are colder.

That's a good point on the 850s. It's definitely going to be cold. I was thinking downsloping might offset some of the cooling, so that it would be very cold, but not extremely, bitterly cold...which I believe you mentioned above. Foothills suggests that the model already factors this in. I didn't know that.

[Cold Rain]

Extreme events have happened a lot and I mean a LOT in the Southeast over the last few years. Its the "average" we can 't seem to get much of anymore. Hottest summer in "recorded history", Coldest Winter in 30 years. Big time record snows in Apps. Floods in GA, eastern Carolinas. Drought never ending in SC. Its all been pretty well forecast I think., depends on which forecaster your using I guess. And the heatwaves and coldwaves are seen from quite a distance away usually. The biggest part is figuring the degree to go extreme.

You have a point, definitely on the long term or seasonal stuff. Last Winter, for example, there were a lot of very cold forecasts, so they verified pretty well. I guess I was thinking more of individual storm systems or artic outbreaks, individual events like that, that show up on the modeling and seem to always get tamer as you close in on them. Sort of like this one...earlier, models had a 975 lp near this area (although I don't remember the specifics on this) and the 510 height line well into NC. Now, mostly the 516 height line stays north of the area and the LP is up in the Lakes. It never goes the other way.... a 950 LP with the 498 height line through upstate SC. That's ridiculous of course, but hopefully it illustrates the point.

Just once this year, I want to see a winter storm show up on the models for this area and get more intense and threatening as we move in closer. The last one I remember working out like that for my area (and there have probably been others since that I'm just not recalling) was the Dec. 2002 ice storm. That kept getting colder and colder and wetter and wetter as we moved in, and we all know what happened with that one.

Anyway, as always, I appreciate your (and all the others') analysis.

[WeatherNC]

It's a Christmas Miracle Charlie Brown...

[CAD_Wedge_NC]

I guess this is the right thread......... Here is an example from GSP on what I was referring to in an earlier post about the strange temperature swings with winter precipitation events. It happens every winter here. We all know that here in the damming areas, you never get that much of a temp variation with precip. falling. This has to be all computer generated. Anyone else notice this in their forecasts??

Wednesday Night: Mostly cloudy, with a low around 26.

Thursday: A chance of rain, freezing rain, and sleet. Mostly cloudy, with a high near 46. Chance of precipitation is 30%.

Thursday Night: A chance of rain. Mostly cloudy, with a low around 33. Chance of precipitation is 30%.

Friday: Partly sunny, with a high near 48.

[NCBlizzard]

I guess this is the right thread......... Here is an example from GSP on what I was referring to in an earlier post about the strange temperature swings with winter precipitation events. It happens every winter here. We all know that here in the damming areas, you never get that much of a temp variation with precip. falling. This has to be all computer generated. Anyone else notice this in their forecasts??

Wednesday Night: Mostly cloudy, with a low around 26.

Thursday: A chance of rain, freezing rain, and sleet. Mostly cloudy, with a high near 46. Chance of precipitation is 30%.

Thursday Night: A chance of rain. Mostly cloudy, with a low around 33. Chance of precipitation is 30%.

Friday: Partly sunny, with a high near 48.

yea thats absurd, but it seems like thats always the case with their longer range forcasts. (as far as temps go)

[ICEAGE NOW]

I know its 8 days out and beyond, but the models (plural) generally seem to be breaking down the cold pattern after about the 18th/19th. Something to watch (given this thread is "December 14th and onward...").

Any thoughts on pattern change, implications, duration?

Thanks!

Met. Alan Huffman out of Raleigh said on his blog today, we could get another arctic outbreak around Christmas again, so I don't think it's going to warm up anytime soon.

My thought's on this winter is because of the cold here in early Dec. has to do with low sunspots and alot of volcano's this year around the world is having something to do with our winter , just my thoughts.

[Rob]

Nashville would be a mess if this pans out..... I could see this happening given the amount of low level cold air present.

[NCSNOW]

Greensboro (PTI) as of December 10,2010 has a monthly departure of -10 . December 2010 is at 33.1. I remember December of 1983 and how cold it was over the holidays. But 2010 has the chance to go wall to wall IMO. We could be experiencing the coldest December on record. Won't make a hill of beans to most folks w/o the snow. Everything is set-up for this to happen. Checked Euro and GFS Nao forecast and it's in the tank all the way out to 12/26 now, which is as far as it goes. Now if we can roll into January with this mojo and get a little moisture to time right a few times, we'd all be swearing off ever paying attention to another seasonal LR forecast by March 1st.

[DCMetroWinston]

Well, GSO has already had 2.0 inches of snow this month, so it will not be a snowless December.

[NCSNOW]

Well, GSO has already had 2.0 inches of snow this month, so it will not be a snowless December.

Yea good point. I still saw alot of snow up in the shaded areas yesterday up in Winston. Really one or more minor events and record cold and i'd say we are off to a great start. Things till now are far exceeding my expectations. Lets hope it conitues that way the through the next 80 days

[HKY_WX]

I'm sure we'll get another storm eventually with the NAO in this state. I actually like the look of the system for day 5/6. But the NAO is certainly throwing a wrench in the seasonal forecasts. If it keeps up throughout the winter and la-nina were to fall apart like some of the dynamical enso models are suggesting, february/march could be very interesting as we could see the PDO/PNA become more favorable.

[POWERSTROKE]

I'm sure we'll get another storm eventually with the NAO in this state. I actually like the look of the system for day 5/6. But the NAO is certainly throwing a wrench in the seasonal forecasts. If it keeps up throughout the winter and la-nina were to fall apart like some of the dynamical enso models are suggesting, february/march could be very interesting as we could see the PDO/PNA become more favorable.

i agree, think next storm could be a surprise

[SBUWX23]

Anyone notice the 1060 mb high modeled by the GFS to be in the arctic next week. I believe the Euro has a near 1070 mb high and from what I can tell the models are showing a rare rapid ANTIcyclogenesis up there. What a pattern!

[Brian]

Anyone notice the 1060 mb high modeled by the GFS to be in the arctic next week. I believe the Euro has a near 1070 mb high and from what I can tell the models are showing a rare rapid ANTIcyclogenesis up there. What a pattern!

Please for us dumasses, what does that mean? Not trying to be insulting, but a lot of us cannot figure out what that means. Thanks :snowman:

[SBUWX23]

Please for us dumasses, what does that mean? Not trying to be insulting, but a lot of us cannot figure out what that means. Thanks :snowman:

Basically it means the blocking and -AO means business. Who knows if it will verify but there may be a nasty cold airmass building somewhere up there with that.

[FoothillsNC]

Anyone notice the 1060 mb high modeled by the GFS to be in the arctic next week. I believe the Euro has a near 1070 mb high and from what I can tell the models are showing a rare rapid ANTIcyclogenesis up there. What a pattern!

I saw that too. The blocking/ridging going on in Canada to Greenland is going to allow a mega high to form. We'll see if that works out. If we ever got a big PNA out west, that would possibly be quite the arctic outbreak somewhere.

[burgertime]

Basically it means the blocking and -AO means business. Who knows if it will verify but there may be a nasty cold airmass building somewhere up there with that.

Me thinks if it does you might be having a lot of fun up their in NYC.