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Pattern February Discussion

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Cad Wedge NC said:
ao.sprd2.gif

AO forecast to plunge..... PNA forecast to remain positive. If only the darn NAO would go negative, we would be in great shape.
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Here's the problem with the GEFS AO forecast: strong -AO bias over the four months covered by these graphs (~-1 bias at day 14). The easiest way to see this bias: mean AO since Oct. 4 has been +0.1104 (see top of the 4 graphs). Next, check out the bottom graph, which is based on the day 14 forecast: average day 14 prediction is way down at -0.9349! So, -0.9349 minus +0.1104 = -1.0453, which is the day 14 GEFS forecast bias.

Another easy way to clearly see the bias: in the bottom graph note how much higher is the black line (actual) vs the blue line (day 14 forecast). The black line has been above the blue line almost every day since 11/5!

I like that today's day forecast has dropped back down to ~-0.50. The lower the better. However, in order for me to have decent confidence in the AO actually going negative at day 14, I'd like to see it down to something like -2 to -3. Look at the day 14 forecast for late Nov.: it was almost down to -3 yet the actual verified only down near -1. Also, the forecast for mid-Jan was down to near -2. Yet, it verified near 0.
 
Shawn said:
Well Eric, at least you didn't go "cold and snowy" because you're a weenie or money grabber. Doesn't matter exactly how much you were off on warmth, you had the general idea that looks to be coming true.

And guys, I know seeing a prolonged period of "blue and green" on temp anomaly maps is good to see, but it isn't required to get a Winter storm. The month can be above average, and still produce a Wintry event. I have to go back and research more into the year, but in 1973 we were close to 80F here in CAE before the infamous snowstorm (biggest on modern record here), and then a few days later we were back to the 70s.
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Note that both this historic 2/1973 SE snowstorm and the 3/1993 Storm of the Century were during +AO/+NAO. So was the big 1/1988 snow and sleetstorm. The 1/1988 did, however, have a favorable for cold MJO.
 
Shawn said:
I think it gets your point across easier.
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It does, sometimes when something is interpreted in text it can cause confusion...when interpreting it in visual form, the interpretation becomes clear. Shining the light through the darkness.

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Where's Phil at? He has to give me some song ideas for tonight's runs. Lol.

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If anything, I definitely would be more concerned about severe wx than wintry weather in the southern US atm next week esp w/ at least one or two lows cutting into the Great Lakes &/or TN/OH Valley. Severe weather climatology (esp over Dixie Alley (MS/AL/GA)) usually begins to significantly ramp up in February...
 
If this happened to be the solution, the second low is so strong it's throwing some backside snow behind it but I wouldn't count on it.
 
Webberweather53 said:
If anything, I definitely would be more concerned about severe wx than wintry weather in the southern US atm next week esp w/ at least one or two lows cutting into the Great Lakes &/or TN/OH Valley...
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Yup, that's a severe wx outbreak. 0z Euro OP showed severe wx OH River down to the MS River as well.

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Hilarious another solution GFS throws in the 12z run this one actually would supply a light backside snow event for North MS/AL... but who the heck knows at this point I'll save my winter is dead gif for now though
 
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