Winter Starting Off Strong for Some

CPC Graph of NAO and Forecast

Winter is off and running. It’s not terribly uncommon for La Nina winters to start off bursting out of the gate. But this winter is almost a carbon copy of last. And one of the big reasons we have to thank is the NAO. If you look at the image on the right (top frame), it shows a chart of progression of the NAO index since late summer and the red lines indicate the forecast. The NAO has been negative for months. We’re clearly in some sort of funk or cycle of it. When the NAO goes negative, in a nutshell, you get a large ridge of high pressure centered near or over Greenland (NAO is often synonymous with “Greenland Block.”). When you get large ridges, that usually means there are large troughs on opposite sides of the ridge. And geographically, Europe and the Eastern US are on the opposite sides of Greenland, so…there you have it.

Greenland blocks can often be favorable for lake effect snow, and there has been a LOT of lake snows. We’ve seen this pattern several times in the last few years, but because often times the winds have been either too northerly or too westerly, the snows have hit more remote areas. Now, Syracuse is getting hammered with over 30″ of snow so far this month (and potentially a LOT more coming)! When snow records start being set in the ‘Cuse, that usually means we have a pretty impressive weather pattern or storm ongoing. Here’s a look at the NWS watch/warning map from this afternoon. You can see the lake effect snow warnings in Central and Western New York, as well as the deep blue on the Gulf Coast, indicating hard freeze warnings. This is VERY early for cold of this intensity in places like Florida. So we’re in it pretty hard right now, and it’s only going to continue for the next 10+ days.

Want relief? My forecast highs out here in SoCal are in the mid 80s for early next week…that’s balmy! It’s all related though, as the sharp trough in the East, generally means an amplified sharp ridge in the West.

So what about the storm for the weekend? I’ll probably talk more about this tonight after a nap and some errands. But the operational models track the storm over NY, with both the Euro and GFS ensembles slightly further east with the center of it. To me, this would imply the operational models are a little too far west, and I’d hedge my bets a little further east. This means: Heavy interior snow, with some area of freezing rain somewhere in between, and mainly rain on the coast and for the big cities. I have a feeling that parts of Central or Western NY might get clobbered with this. Especially if we trend more toward a slightly flatter GFS storm.  Expect a sloppy mess in the interior regardless Sunday and Monday. Again, more on this later


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