SOME FLAKES STILL FLYING...
Tuesday storms system pretty much did what was expected of it, depositing 1-3" of snow over my entire area. It even over delivered in far southeast Iowa and WC Illinois where a mesoscale band of heavier snow produced 4.5 inches at Donnellson, Iowa and 4.0" in Galesburg, Illinois. Pretty darn good for November 15th. Here's a map depicting snow totals through Tuesday evening.
This larger perspective covering a 12 hour period shows snow accumulated from Arkansas all the way to the Canadian border. That's extremely unusual for mid-November and a testament to the strength of cold air that's dominating the nation.
This is really impressive. It's the accumulated snowfall for the season through November 15th revealing more than half the nation has already experienced snow. That's far from common.
Compare that to last year below. Not only is the coverage far greater in 2022, the amounts are heavier from the west into the northern Plains and upper Michigan.
On this low level wave satellite imagery you can see Tuesday's system moving into the Great Lakes and another wave of energy diving into Montana. This new energy actually turns todays system back to the south where it and the new cold that's coming, keeps occasional periods of light snow or flurries going the rest of the week.
Overall, any additional snow will be banded in nature which will make accumulations hard to predict. Some will see little snow at all while others could pick up an inch, perhaps slightly more in some local spots. This mesoscale banding is just about impossible to pin down other than it's expected in spots. Here's what the HRRR and 3k NAM (high resolution convective allowing models) indicate for totals. Such amounts should not cause major problems with marginal temperatures close to freezing.
The 3k NAM
The EURO came in with this for snow the rest of the week.
After a relatively "mild" day Wednesday (that's a joke) with highs in the low 30s, an Arctic front sweeps in during the day Thursday. This long advertised shot of cold air will be accompanied by strong NW winds that could reach gusts of 30-40 mph. The intense cold air aloft (as cold as -15C at 5,000 feet) will drive instability as well. Scattered brief but intense snow showers (snow squalls) are likely that for very short periods of time that could produce low visibility with the strong winds.
As the cold deepens temperatures will fall Thursday afternoon and by Friday morning readings will be down in the upper teens and low 20s rising little during the day. Wind chills all day Friday will be in the single digits and it gets worse. By Saturday morning lows should be down around 10-15 and Sunday morning in the range of 5-10 degrees!
Readings that cold are projected to be 25-35 degrees below average.
Just for kicks, there should be enough wind to produce sub-zero wind chills Sunday morning that could reach 10 below north to zero in the south. Ugh....
As for weekend highs, both Saturday and Sunday they hold in the mid to upper 20s. Far below the 40s which are typical in mid-November.
Now, for those of you down in the dumps about this early explosion of winter, some good news. One of the big drivers in our recent plunge in temperatures is the EPO (eastern Pacific Oscillation). As you can see below the next 2 days it's more than 7 standard deviations below the mean...literally off the charts. Notice by Thanksgiving the EURO has it going positive and staying there for about a week before taking another dive.
The negative EPO is a major climate factor as the high pressure it produces in the eastern Pacific and Alaska, buckles the jet over the Rockies allowing the cross polar flow that brings cold air, in our case an Arctic front that arrives Thursday. However, when the EPO goes positive like it does next week the ridge is flattened and a zonal component to the jet is the end result. Pacific air replaces the polar air we recently gained access to.
Additionally, the MJO is set to sweep into phase 6 around November 21st which in November analogs to mild readings.
In conjunction, the EPO and MJO point to a week long period where temperatures should be near to above normal. The GFS has a 500mb jet stream look that certainly mirrors phase 6 in December (which is what we will be coming out of the 1st of December).
These are the associated temperature departures December 1st. Compare that to the phase 6 analog above, especially in December. That certainly fits the warmer look the teleconnections are signaling.
So, I am expecting a warm-up to close out November that could last the first few days in December. However, if you go back up to the MJO forecast, you can see it cycling back into 7 in December which analogs to cold.
Here are the temperature and precipitation analogs for phase 7 in December. Far different than what phase 6 produces.
To sum it up, we should be moderating nicely by the end of Thanksgiving week. But, we could very well be trending back to cold in early December if the MJO swings into 7 as projected and the EPO turns negative once again. That is on my radar to watch.
That's all for this go-round. Make it a solid day and roll weather...TS