Joe’s Weather World: December starts with a snow risk (MON-11/30)

Weather

November will go down as a mild month here in KC…and in the so what else is new department…a dry month as well. As we finish the month we’ll end up about 6° above average for temperatures. That’s the 10th warmest in KC weather record history. It was actually warmer as recently as 2016. That winter we had less than 5″ of snow around here.

It was also dry…again. Continuing a trend that took control in early August. We’ll end a normally dry month with about a 1/2″ deficit. Which when looking back to August 1st now makes this the 6th driest August 1st through end of November in KC weather history and the driest we’ve been in that time span in almost 45 years.

Things though may change briefly towards the middle of the week as a really weird weather pattern is setting up this week in North America with all sorts of upper level systems spinning around, with really mild air (by average sakes) up across a good chunk of central and northern Canada. Weird things aloft in my opinion usually mean not to let your guard down about weird potential in the Plains.

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Forecast:

Today: Sunny and seasonable with highs around 40°

Tonight: Fair and chilly with lows near 20°

Tomorrow: Mostly sunny and pleasant with highs well into the 40s.

Wednesday: Increasing clouds and cooler with a rain or wintry mix possible later in the evening. Highs around 40°.

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Discussion:

So let’s briefly dig into the November stuff…as I mentioned one of our warmest Novembers in weather record history…going back to the 1880s.

and continuing this dry spell that we’ve been in since August 1st.

It’s not the greatest look heading into the winter season in my opinion. Things certainly can change, especially with respect to the moisture situation…but at least over the last 90 days or so…the main “Best moisture” has been down towards and south of the I-44 corridor.

Moisture deficits in the last 90 days…very dry locally.

Although in the past 30 days…this did get a bit better across NE KS and NW MO…jut a bit comapred to average and remember the average in November isn’t too high.

Last 30 days of precipitation deficits.

We average about 2.1″ of moisture in November…it’s even lower in December.

So some moisture would probably be welcome and there is a chance this week. Perhaps heavier towards SE KS and SW MO…but something may get up into the KC area.

This week is an interesting weather week…a large and strong upper level low will be developing across the eastern 1/3rd of the country. You can clearly see that when we go up to about 18,000 feet or so in the atmosphere. This is for tomorrow morning.

This will create a heavy accumulating snow towards the OH Valley area.

The Cleveland and and surrounding area will get it pretty good…as the Lake Effect gets turned on as well too.

As this happens…a wave will be digging in towards Montana and dropping into the Eastern Plains of CO…and dropping southeastwards into Tuesday night towards the TX Panhandle. To add a bit more complexity…then a 3rd wave will be dropping into Montana from Canada and dropping south through the Rockies. So that by Wednesday morning we have this hot mess.

The 3rd wave will have little to no moisture to work with…the 2nd wave won’t have a lot to work with (but perhaps just enough) and the 1st big upper level storm will be so stretched out by Wednesday evening that moist of it’s moisture will be flung away from its core. Notice as we look at the available moisture in the atmosphere later Wednesday that there is a very dry wedge of air into the SE part of the country and across the western 1/3 of the country. The 2nd wave though has something to work with in SE KS and SW MO.

The #2 wave on it’s own would probably remain south of the area…BUT with the help of the #3 wave…it will actually get a bit of a kick farther north as the two sort of revolve around each other to some extent. So that by Thursday morning we have this pattern aloft. You can say the “eyes” of the weather will be in the Plains during the middle of the week.

Note that BIG ridge over the top across the NW and southern Canada.. That is impressive and represents a crazy amount of warm air that is surging through the NW Territories compared to average. The next map shows the 5,000 foot temperatures and almost a 50°F (!) departure in average at that level.

At the surface temperatures will respond…some 50° above average up there. They should be sub-zero all the time just about…not this week.

Via geology.com

A record high near 32° is possible in Inuvik, NT (way up in the northern part of the NW Territories) on Wednesday. Considering their average high is around -4°…that’s pretty good.

Back to us…and the pirouetting upper level systems. So rain will be developing to the south on Wednesday and moving northwards up the State Line. This will occur Wednesday evening and initially it will be fighting dry air below…chewing away at what falls. This will also help to cool the atmosphere down so that IF we get rain to start the event…the atmosphere would be getting in a more favorable state for snow production later Wednesday night into Thursday early morning.

So then the issue is how much moisture do we get when the atmosphere is in this more favorable state and how far north is the better precip totals…translating into at least some wet snow accumulations. This is the tricky proposition at this point because IF the pirouetting systems don’t do this correctly…the best lift and moisture could stay south of here when things are set-up for snow.

The new NAM model has this idea for total moisture between 12AM THU and Noon THU. Roughly a 1/2″>2″ potential.

The GFS/EURO has this idea…use the slider bar (data from overnight).

Slide RIGHT for GFS and LEFT for EURO

About 1″ on GFS and near that on the EURO. This would likely be happening at night so while there may be some initial melting…it should stick. How much it sticks to the pavement though is a bit of a wildcard. We’ll need to watch the commute on Thursday morning.

Whatever falls will slowly melt later Thursday or Friday assuming we don’t get messed up with clouds (possible)

So at this point it doesn’t look to be a major winter event…but it is December so I guess we can start thinking about snow now. To be honest it may be on one decent chance for awhile.

Had a beautiful full moon this morning…here is a shot of it from Tiffany Lanier in KCK

Joe

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