Can We Drop Below 0° Tonight?
When you think about where we started the week, and we’re we’re heading tonight…wow! That’s why I love the weather, especially in this part of the country. While it drives many nuts, for those of us who have a passion for this stuff, it gives us lots to talk about.
We started with record highs on Monday and Tuesday then dropped yesterday and we’ve been going down ever since. We’re into the teens now and with NW winds of 20-30 MPH it feels closer to 0° with sub-zero wind chills across N MO as I type this. Skies are partly cloudy and there is a big arctic high building down through the Plains this afternoon with plenty cold air moving through. Here is the surface map showing the area of High Pressure building down.
That high will sink right towards us tonight so that by daybreak it’s located between here and the Lake of the Ozarks. Here is the RAP forecast for early tomorrow AM.
So what will it take for us to drop to 0° or below…1) we need clear skies…that should work out although I wouldn’t be shocked if we get some clouds moving through towards daybreak. 2) Light winds…right now that is not the case, but later tonight the winds should drop off to around 5 MPH. 3) Dry air…dewpoints now are close to 0° and may drop a bit more later tonight. 4) this one is more for me to watch, and that is a lack of a southerly component in the surface winds which we should be OK till just after sunrise when the winds switch towards the SW. So with all that said the last time we saw lows of below 0° was some 722 days ago! Here is a graphic from the NWS in Pleasant Hill from last week, talking about sub-zero temperatures.
Also if you remember last week we talked about how snowcover plays such a large role in these scenarios…remember only 6% of the times there has been sub-zero lows we had little to no snow…so it’s relatively rare. Once we move into the trace to 1″ snowcover, the number of times we’ve been sub-zero increase s to 20%…so the snow plays a large role in these forecasts.
My feeling is that KCI will drop to -2 to +2° tonight so I’d probably forecast 0° on the news tonight. at this point MT is going with +2° with the reasoning, and he’s right, that we’ve had such a hard time dropping down this year (7° so far). Aloft the air really isn’t cold enough to get us to below zero, but on the surface the air across the Plains is about as cold as it has been so far this winter. So it is a tricky forecast. For areas from 36 highway northwards though it seems pretty easy that lows will drop to 0° to perhaps as cold as 10° in some isolated areas tomorrow AM with that deeper snowpack. Now if you think it’s cold, think about the upper Midwest where wind chill factors tomorrow AM may be 50 to 60° below zero.
What’s fascinating about this winter to me has been the abrupt airmass changes across the region. This will be another fast transition to a warmer airmass over the weekend as the cold moves out and warmer air starts to move back in. Take a look at the temperatures across the US over the next few days from the GFS model.
The top left map is for 6PM tonight and it goes every 12 hours through 6AM SAT. These are the temperatures at about 5K feet (850 mbs) and even if you understand very little about the weather, you can see how those colder purple-red colors are being shoved away over the next 36 hours and replaced by lighter blue colors. This means that we should warm up to near, if not above 40° over the weekend.
At this point there are no other significant storms showing up to talk about, there maybe something in about 8 days or so, with something possible next weekend.
That’s it for today, I’m working on a little research project for tomorrow’s blog that talks about how this winter is comparing to last winter from a temperature standpoint. I hope to blog about that tomorrow afternoon.