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Last October I did my annual winter forecast for the southeast and theirs no denying I blew the temperature forecast big time! I relying on some long range modeling and teleconnections that pointed to La Nina having an influence on us with mild and dry conditions. I did though feel that much like last winter the negative N.A.O (North Atlantic Oscillation) and the negative A.O. (Arctic Oscillation) would help cancel out some of the effects of the La Nina. I just didn’t foresee how negative both indices would get. The net results of these 2 indices being negative especially the A.O, which may have been at record low readings, has resulting in the second coldest winter in the past 69 years here in Charlotte. Here is what these 2 indices do to our weather patterns across the southeast.On the left in the figure you can see the impacts of a positive A.O. on the left and a negative phase on the right. Notice how when the A.O. is negative both Europe and the eastern U.S. have really cold winters. You also will notice that Greenland and parts of eastern Canada have warm winters.
When you look at the effect of the N.A.O you have very similar impacts when this index goes negative.
Positive N.A.O Negative N.A.O
Looking at these 2 indices you can clearly see why we had such a brutal stretch of cold weather the past 2 months. Though notice the forecast 10-14 days out into middle and late February. You can see for the first time in almost 2 months these indices are going positive. Which will likely mean a significant warming trend for late winter. This is no grantee that we’ll be done with the cold and snow, but likely those cold episodes will be fewer and shorter lived later next month. I also should note here that climatological Charlotte has it’s biggest snows in February and March. This is due mainly to better timing of the moisture and cold air as the cold air is retreating and warmer air is coming north.
Here is where we stand today across the southeast for ranking the coldest winters in the past 69years. The numbers represent the ranking this winter for coldest mean temperatures so far, through Jan 27th, 2011. We’ll see if this late winter warm spell will be knocking us further down the list but with 2 solid months of cold it’s not likely 2-3 weeks of warmer weather in February will have much impact on the final numbers.
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,North Atlantic Oscillation
While our large winter storm is looking more and more like a very good cold and soaking rain for the Charlotte area. There’s still a chance for a little snow at the end as the storms moves out. If you live north and west of HWY 64 be ready for a heavy wet snow. Here’s the run down of what could happen based on the current data.
Here’s where the storm is right now.
Here’s the ECMWF model with a cold pocket aloft moving overhead Wednesday evening. This will likely change the rain to a quick bust of snow Wednesday evening, something I’m watching closely.
NAM model kind of does the exact same thing at the tail end of the storm theirs a period of heavy snow for 1-3 hours, right over the western Carolinas. Including a large section of the piedmont.
NAM sounding shows it too!
Forecast scenarios right now:
Charlotte/Metro and surrounding area:
The basic gist right now is mostly a cold rain from Tuesday night into Wednesday afternoon for Charlotte and the surrounding piedmont. Then late Wednesday a brief period of snow and colder air re-freezing roads which could cause some slick roads on Thursday morning.
I-40 Corridor and northern piedmont:
Likely a cold rain too but some wet snow mixing in from time to time. This is the one area that a small shift in the track could bring accumulating snows. I wouldn’t be shocked to see more snow here than we are thinking right now.
Mountains and areas west & north of HWY 64:
This is likely going to be a very wet heavy snow with rain mixed in. Accumulations could be from 1-3” below 1500’ in elevation but above 2500-3000’ accumulations could be 4-8”. Need to watch closely in case some cold air gets trapped in the high mountains valleys, then we could see some freezing rain mixed with snow. Likely going to see a Winter Storm Watch issued here by tonight.
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There have been some significant changes in the forecast guidance or models since Wednesday. Some good news, less ice potential, some bad news, lots more snow and maybe near Blizzard like conditions for the mountains and foothills Tuesday into Wednesday next week. Here’s the latest…
The arctic air is the first ingredient for the storm and it’s moving into the Midwest and Ohio Valley today. We are just now seeing the leading edge of this arctic air mass.
Latest GFS 6Z run for Tuesday night at 7pm.
Here’s the ECMFW the 0Z run for Wednesday morning at 7am.
GFS possible snow totals
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Arctic air is building over a large section of Western Canada, Alaska and now the Dakotas and it’s on the way south this weekend for the Carolinas. This is going to set the stage for a potential ice storm for parts of the western Carolinas starting Monday into Tuesday. Here’s a look at the set-up I’m looking at today.
Here’s the set-up based on the GFS model.
Soundings look like mostly freezing rain at this point and time.
Here’s how freezing rain forms, (NC State Climate Office graphic)
Well we saw this one coming for days but it still ended up being an amazing winter storm for the Carolinas. It started early Monday morning around 3-4am and kept going until mid-day on Tuesday. By the time is was all done a solid 4-6” of snow fell across the area with localized higher amounts. The really damage though was done on Monday night into Tuesday when a .25” of ice in the form of freezing rain fell on top of the 4-6”. Here’s a look at the final accumulation maps from both North Carolina and South Carolina.
The amazing shot from space truly shows the reach and size of this storm.
When it was all said done Charlotte-Douglas International Airport picked up officially 4.1” which is a new daily snowfall record for Jan 10th. The old record was 3.0” in 1962. this is also the first 4” snowfall since 2009. For the whole winter we have officially had 6.1” making this the snowiest winter since 2003-2004 and it’s only early January.
I still like 3-5” for Charlotte with .10” of ice, yuck!
This is our Futurecast Model Snowfall Forecast
The National Weather Service Forecasted snowfall
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