Don’t put away the sweaters and winter jackets just yet. We have not seen the last of cold temperatures across the Midwest and Mid-South and areas near the Great Lakes have not seen the last of the white stuff either.
This recent pattern shift is very similar to the one that occurred back in late January – early February. After a balmy December and early January, February started out with 7-10 days of near record lows but little snowfall, since the polar jet dominated the flow. By mid-February, the southern jet became active and the combined with the cold air in place to produce a number of big snows for the Midwest and Northeast, including the Valentines Day blizzard. March, like January, was very warm and dry while April has started with record-breaking cold but dry conditions as the polar jet has dominated the flow. Now, the southern jet is becoming active and a series of Colorado lows will lead to cool and stormy conditions across the eastern U.S.
The first relatively weak storm will bring showers and thunderstorms to the Mid-South and a few inches of snow to the Great Lakes. A second, more potent system will affect the region Friday-Saturday with a risk of severe weather for south-central KY. Sunday looks like another raw day with low clouds, gusty northwest winds and highs in the upper 40s. The 12z GFS shows scattered rain showers across KY and possibly snow showers as far south as central IN and OH. When comparing the cold of this coming Sunday to that of last Saturday, you can see that last Saturday the thickness over KY was 522 dm and the 850 mb temps were around -10 which translated into high temperatures of 40 Saturday afternoon. The GFS has been consistently showing a thickness of between 528-534 dm with 850 mb temps between minus 4-6 degrees for Sunday afternoon, which would suggest high temperatures of 45-49 for south-central KY and highs of 40-44 across northern KY with wind chills in the 30s. This is well below the current MOS number of 56. If this were Jan or Feb, I would definitely put snow showers in the forecast for Sunday, but since it is nearly mid-April, it is much trickier. My main concern is that there is a strong short-wave that will be moving through the bottom of this trough Sunday which could provide enough extra lift to squeeze out some frozen precipitation across northern parts of KY, especially across the Bluegrass region.
Unlike this past weekend, this is a very narrow trough so temperatures will rebound quickly heading into early next week. A clipper system is expected to bring a return of chilly air to our area mid-week with more snow showers for the Great Lakes and the possibility of a significant snowstorm for New England by the end of next week. Looking forward, I expect the unsettled pattern to continue through the end of the month.