Sunday, November 11, 2018

Update on #Novembrrr cold & wintry precip chances Tuesday.... and Thursday

This is the promised follow-up to Saturday morning's blog on precipitation early Tuesday morning, as well as broaching yet another possibility from a system the models have just started picking up on in the past 24 hours or less. Let's take them one at a time... (And yes, seriously, why are we talking about multiple "potential" events in mid-November! There should be a law.)


Monday/Monday night

First, Monday remains on track to be cold and wet. Get the waterproof winter coats out because low 40s on the thermometer, rain, and a north wind gusting to 20-25 mph is NOT going to feel great. The trend with this system the past 24 hours though, as far as the wintry precipitation is concerned, is positive (unless you want a snow day).

As discussed in yesterday's blog, models tend to move the precipitation out faster and the cold air in slower as we draw nearer to an event. Not always, but many times. That is happening this time. A general drying trend should take place, especially after midnight (early Tuesday). In addition, the "sufficiently-cold" temperatures for snow production are dragging their heels just a bit.

The morning run of the GFS model mirrors other model solutions in depicting almost no precipitation after midnight Monday night when temperatures finally fall far enough to produce snow.  Notice that the precipitation shifts to the east as the freezing line arrives from the west. Not atypical for our area, especially in November. (WxBell)

The result is that I have pulled all snow from the forecast on Monday night. There could be a few flurries in the wee hours Tuesday morning with temperatures just above freezing. You likely wouldn't even see them unless you work on the FedEx or UPS ramp overnight. Tuesday looks to be dry and very cold with highs in the 30s and wind chills in the 20s. I've also become more "negative Nelly" on sunshine Tuesday. Yuck.

Wednesday/Thursday

The negativity on Tuesday sunshine is directly influenced by another system that now looks like it might have an impact on mid-week weather. If it does, 3 T's - timing, track, and temperatures - will play major roles in its impact on our area.



As the main system Tuesday departs to our northeast, a piece of upper level energy now looks to be orphaned behind over the southern plains. Multiple models are now forecasting that energy to strengthen into a potent upper level low and move near the Mid-South. Because this feature is just now being picked up by models, the track and speed (timing) are different between the respective models. The only certainty is that the solutions will change over the coming days, so I'm not ready to get too excited by it. But apparently some of your weather crap apps are!

A loop of the atmospheric energy at about 18,000' (500 mb) from Wednesday morning through Friday morning, as depicted by the Sunday morning GFS model. That "bowling ball" of reds and purples is a strong upper level low pressure system that will bring a round of precipitation and very cold air aloft. Models still differ on track and timing, but it is worth watching. (PivotalWx)

The same model as above (Sunday morning GFS) only showing the surface precipitation amounts associated with the forecast track of the upper low. Note the colors are NOT precipitation type, but amount. The blue lines that encircle the Mid-South as it moves north are sub-freezing air at 5000' and indicate a potential for snow if surface temperatures are also cold enough. (WxBell)

We'll take the cautious approach for now, as the track, timing, and most importantly, temperatures in the mid and low levels of the atmosphere, will determine A) if we get any precipitation and B) what form it is in. These deep lows are carriers of very cold air aloft, so if temperatures near the ground are near freezing (and that depends on timing), there is another chance we could see some flakes. For now, the only flakes are those that randomly spit snow totals for Thursday. :-)

We'll keep you posted. In the meantime, here's a look at the temperatures for the week ahead, subject to change based on the ultimate fate of the mid-week system. The latest forecast can always be found in our mobile app or on the website. Links below. Stay warm!


Erik Proseus
MWN Meteorologist

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