February will start off rather cold across much of the Midwest as a high-impact winter storm skirts to the south bringing heavy freeing rain and sleet. By the upcoming weekend, temperatures moderate and trend above normal as we head into the first full week of the month.
Guidance supports above-normal temperatures continuing through the middle part of the month, and potentially through the end of February. The map above shows the probability of warmer-than-normal temperatures February 6-9 based on historical analogs.
The latest Climate Prediction Center forecast agrees with the historical analogs with this warmer solution. Their forecast, valid February 8-14 has high-confidence in mild temperatures especially around the Great Lakes.
‘Mild’ this time of year translates into highs in the 40s and 50s. While not ‘warm,’ for much of the region this is at least 10° above normal.
Looking at forecast models, you can see multiple days well into the 40s through much of Iowa into southern Wisconsin by February 6 and continuing through at least the 10th. Central Missouri into southern Illinois, including the St. Louis metro area, have a good chance of reaching mid-50s February 6-7.
So how long does this above-normal trend linger? Extended-range forecasting requires the use of teleconnections that can guide patterns. A useful tool known as the MJO has the index moving into Phase 5 and 6 deeper into February. So what does that mean?
Centered over February, Phase 5 and 6 are quite mild across the United States, especially the Midwest and Great Lakes. This is quite a strong signal for above-normal temperatures through at least mid, if not late February.
Over the next month, the only really ‘cold’ potential signal is what is happening high up in the stratosphere. There are some indications the stratosphere may begin warming quickly. This can dislodge the Polar Flow causing the dreaded ‘polar vortex’ swinging farther south. This is something that, if it were to occur, is two-to-three weeks away and confidence is quite low., but that’s about the only interesting thing to watch at range.
-Nick