Much of the Northern Tier of the US will face temperature and weather extremes Thursday through Saturday as a near-stationary warm front drapes itself over the region, setting up from Nebraska, through the southern Great Lakes region, and into the Northeast.
This Thursday, while high temperature soar to above average and even record-breaking levels, the Northern Plains, Upper Midwest, and Great Lakes regions will be on the cool side. The Southern Plains through the Southeast can expect high temperatures in the 90s. Highs in the 80s will be more commonplace to the north in the Central Plains, Ohio River Valley, and Mid-Atlantic. The Northeast will also be mild with high temperatures in the 70s. To the north of the warm front, however, high temperatures in the 50s and 60s will be the theme for most.
In terms of the rain, waves of low pressure will ride this warm front, so areas near this front will be in store for rounds of rain and thunderstorms. There is also the risk for training showers and storms, which is when heavy rain moves over the same areas for a prolonged time period. That may happen near the Nebraska/South Dakota and Minnesota/Iowa borders Thursday into Thursday night. Some areas may receive as much as three inches of rainfall due to these training storms. There is also the low-end risk for flash flooding.
Now on Friday, the contrast of this warm front will become even more apparent. High temperatures north of the front will be in the 40s and 50s while south of the front it’s in the 80s and 90s. To describe how sharp this front is, let’s compare the temperature for two cities not too far apart: Chicago and Peoria, Illinois. These two cities are 130 miles away from each other and are in the same state, but one will be significantly warmer than the other. Chicago will be north of the warm front, which will keep high temperatures down to about 50 degrees. Meanwhile to the south, Peoria will be at a very toasty, 90 degrees. That is about a 40 degree difference in a relatively short distance. This applies to several other states as well, like Indiana and Ohio. The northern third of these states will have temperatures stuck in the 50s while the southern two-thirds experience high temperatures in the 70s and 80s. This warm front will also impact temperatures in the Northeast, but the contrast will not be as stark. Highs will be in the 50s in western and Upstate New York as well as portions of northern New England. Most areas to the south and east will feel temperatures in the 60s and 70s, however.
Rain and thunderstorms will continue to track eastward along this front, impacting areas from South Dakota through southern Minnesota, much of Iowa, northern Illinois, southern Wisconsin, much of Lower Michigan, and portions of the Ohio River Valley on Friday. A few showers and storms will also be possible in the central Appalachian Mountains. The heaviest of rainfall totals will remain near the borders of Nebraska and South Dakota plus Minnesota and Iowa.
On Saturday, it will begin to turn somewhat warmer in the Midwest and Northern Plains as the temperature gradient weakens due to warmer air flowing in from the West. The biggest contrast will be found in the Northeast. For example, there may be over a 40 degree temperature difference as you take a ride on I-95 from Washington, DC to Boston. In the nation’s capital, the high temperature will be in the low 90s while in Boston it’s in the mid 50s. While highs are only in the 50s and 60s in New York and New England, the Southern and Central Plains through the Southeast and Mid-Atlantic will experience widespread high temperatures in the 90s.
Storms will continue to ride this warm front, tracking east from northern Illinois through the northern Mid-Atlantic and central and southern New England. Some of these locations, especially in the Great Lakes region, may exceed one inch of rainfall during the day Saturday.
By Sunday, the temperature gradient practically dissipates as a surface low pressure moves into the Mid-Atlantic. This low pressure will keep the rain around in the northern Mid-Atlantic region and parts of the eastern Ohio River Valley and southwestern New England. Temperatures will mainly be in the 60s and 70s in this region. Highs in the 70s will dominate in the Northern Plains, Upper Midwest, and Great Lakes. It will remain hot with temperatures maxing out in the 90s across the Southern Tier due to a dominate upper-level ridge of high pressure. This ridge may bring highs to the 100s to parts of the Southeast by early-next week.