Rare Upper Midwest January severe risk Monday

The Storm Prediction Center issued a very rare severe risk area in the Upper Midwest for Monday January 16. The main hazards will be large hail as well as the potential for a few tornadoes.

There are a lot of things that need to go “wrong” for this severe risk to unfold, but there is increasing confidence the instability and moisture will coincide with robust wind shear to allow a few severe thunderstorms to develop.

One key ingredient is the push of very anomalous dewpoint values across the Middle Mississippi River Valley in excess of 50°. Latest high-resolution models are showing just that shaping up, with the trend towards higher dewpoint values in other models as well.

This along with temperatures pushing near 60° will provide rather significant instability given the time of year with very cold temperatures higher up in the atmosphere.

The other key ingredient is sunshine to allow rapid surface heating. Latest models are showing a punch of dry air by late morning into the early afternoon across northern Missouri into Iowa. This surface hating, with dewpoint values in the 50s, is the recipe for thunderstorm development in Iowa.

High-resolution models show thunderstorm development in central and eastern Iowa taking advantage of an environment supportive of supercells.

The potential for severe weather really will not be well known until Monday morning as the clearing and moisture are not of high-confidence at the moment. This is a forecast that will need to be watched closely and further upgrades to severe weather risk areas are possible.

Thunderstorms to snow - wild week ahead in the Midwest

Following a prolonged stretch of above-normal temperatures in January across not only the Midwest, but the entire United States, changes will be brewing in the form of snow potential late next week.

First things first - even warmer temperatures with showers and storms in the Midwest will start the week.

An area of low pressure will push across the central Mississippi River Valley late Sunday through Monday bringing widespread rain and a risk for a few strong thunderstorms. Minor snow accumulation is also possible across far northwest Iowa into Minnesota and northern Wisconsin.

Forecast precipitation of 0.25” to 0.50” will be likely for a very large portion of the Midwest with the heaviest rain in far southern Missouri, Illinois and Indiana. This will coincide with a better chance of thunderstorms that may be on the stronger side of things.

Trends are favoring some potential for strong storms Monday. The above image shows the general risk area based on historical events with a similar setup. A risk for damaging wind gusts, and potentially a tornado or two, exists especially in southern Missouri, Illinois and Indiana.

Check for the latest forecasts from the Storm Prediction Center as the event nears. Given the time of year confidence will be lower this far out as this is not the main severe season in the Ohio Valley.

Forecast snowfall across the northern Midwest will be on the lighter side with limited moisture up that way and temperatures near freezing. Minor road impacts are possible.

Monday’s forecast highs will be 20-30°+ above normal across a huge portion of the region with highs pushing well into the 50s and 60s from about I-80 and points south.

Late in the week, however, temperatures will dive as yet another storm system approaches the region and will pull in colder air - therefore a snow risk is increasingly likely.

Confidence is on the rise there may be an impactful accumulating snow event, especially for Nebraska, Kansas, Iowa, northern Missouri, northern Illinois and southern Wisconsin. Trends have been favoring a “snowier” and “colder” solution Wednesday into Thursday. There will likely be travel impacts with this setup.

Ensemble models are in somewhat good agreement with the general theme of an axis of accumulating snow in this area. Do not focus on the numbers on the above models, just the general area at this range. With about five days before flakes fall it’s too early to determine snow amounts.

We will keep you updated on the forecast as things progress.

Next storm to bring thunderstorms, mild temperatures

The end of the week and weekend will once again be rather quite across the Midwest, but early next week another storm system will bring a shot of warmer air with highs well into the 50s for portions of the area, as well as a risk for showers and thunderstorms.

Through the weekend, East Coast ridging will bring in southwest flow aloft starting the transition to mild temperatures (especially for January) and allowing more moisture to be pulled across the Mississippi River Valley.

Early Monday morning, showers and a few thunderstorms will develop in the area bringing beneficial rainfall. Given the unseasonably mild temperatures this appears to be mainly a rain event opposed to snow which is obviously more typical this time of year.

The best chance for thunderstorms will be in eastern Missouri and through Illinois, while Iowa and Wisconsin are just locked with showers given less instability to work with.

The heaviest precipitation will be found across Missouri, Illinois and Indiana which will be well within the warm sector of this system. Meanwhile, the eastern half of Iowa should see at least a quarter of an inch of precipitation - a number that could be closer to 0.50” is we see some more persistent rains.

The cold side of the storm system will feature a chance for some light snow, but impactful amounts are unlikely as the bulk of the moisture will be focused farther southeast away from the colder air. With that said, some areas could see around an inch, especially northwest Iowa into Minnesota.

There will be a rather large spread in temperatures across the region with southern Missouri approaching 60°. Much of Iowa and northern Illinois should easily climb into the 40s with Minnesota locked more in the low 30s.

-Nick

Long-range signal for colder temperatures to end January

January has been off to a fairly mild start but there are signs pointing to a colder end to the month and beginning of February.

850mb temperature anomalies.

Mid January will remain quite mild across the US. The above map shows the lower-level temperature anomalies for January 15. For much of the Midwest and central Plains, temperatures will run 10°-20° above normal which is a big signal for warmth.

Looking at Natural Gas pricing, levels are the lowest in more than a year - a key sign that commodity traders are looking to this verifying. What comes after this warmup though may be a larger cool down heading into February.

NAO forecast - generally negative values are colder signals in the Midwest

The North Atlantic Oscillation had that big dip below zero in early December which was the cold signal around the Christmas holiday. New forecasts for the NAO are trending back towards values below zero which again is a cold signal. There tends to be about a 10-14 day lag in response to central US temperatures.

If this NAO trend continues to dip colder, this could continue to be a continued trend towards a colder February.

AO forecast - generally negative values are colder signals in the Midwest

The AO has already dipped into negative territory and appears to want to stay there. Once again this is a colder signal for the US and could allow for cold-air intrusion across the central US.

Current snowpack

In order to get a really cold blast of air, and colder air to stick, that air needs to be modified by a thick snowpack. While not immense in early January, there is a good fetch of snow from Nebraska through the Dakotas and this could help make any approaching shot of cold air even colder. This is something that was lacking in December ahead of the ‘bomb cyclone’ that approached the region.

Climate Forecast System long-range outlook

While most operational forecast models we use do not go beyond about two weeks, the American CFS does a daily extra-long forecast. This takes us through late January and into February. There remains a signal for a significant blast of cold air to end the month.

The CFS forecast (above) shows a shot of temperatures running 20°-40° below normal by Jan. 28.

Based on the NAO/AO dipping, I think this forecast has legs to stand on, however this remains two-to-three weeks out. At this range, specifics of a forecast are impossible to show, however you can get a sense of changing weather patterns.

We will see how things progress. One headline worth watching is natural gas price futures in the next week. If prices run higher, the confidence in this shot of colder air will be higher as well.

-Nick S.