March 30 (UPI) -- As the calendar changes from March to April, fluctuating temperatures are expected for the eastern half of the country.
Overall, average temperatures from the Plains to the Eastern Seaboard have been hovering well above normal during the month of March.
Through March 29, the average temperatures reported in Minneapolis and Chicago were both around 5 degrees Fahrenheit above normal for the month. Nashville and Washington, D.C., have recorded temperatures that averaged about 6.5 degrees above normal, and temperatures for March so far were around 6 degrees above normal in Philadelphia and New York City. The average temperature during that time in Buffalo, N.Y., and Atlanta were 7.5 degrees above normal.
"Behind severe weather that erupted in the Plains, Midwest and Ohio Valley on Saturday, cooler air is sweeping through these areas for the last days of the month," said AccuWeather meteorologist Renee Duff.
Cool air will infiltrate from northwest to southeast across the Great Lakes and mid-Atlantic into the middle of the week and the start of April.
"A cooler air mass moving in will bring afternoon temperatures down as much as 15-20 degrees in just a day," added Duff.
Residents in cities like Pittsburgh and Detroit awoke to a much cooler day on Monday. Temperatures in the afternoon ended up as much as 4 degrees to 8 degrees below normal, which felt quite chilly following a warm March.
An even cooler day, at least by a few degrees, is expected on Tuesday in this region.
Farther south and east, the colder air will not arrive until Tuesday, including in cites from Philadelphia to Nashville and Atlanta. Once again, temperatures will drop to below-normal levels for late March and early April.
The temperature drop across the Tennessee Valley and the Southeast will come along with another round of heavy rain and thunderstorms.
The coldest day in the mid-Atlantic and South is likely to be on Wednesday.
All the while, much of Northeast, including New England and cities like Boston and Hartford, Conn., will notice very little in the way of temperature change. Highs will remain in the 40s and lower 50s through the first half of the week.
As is normal in spring, temperature fluctuation is also in the future, and the temperature roller coaster will start to climb for the latter half of the week.
High pressure building in the eastern United States will allow for a more southerly wind flow for many, bringing in warmer conditions.
Afternoon high temperatures are forecast to rebound back into the upper 50s again around the Great Lakes on Thursday, with middle 60s expected to return to the mid-Atlantic by Friday. These temperatures are at or slightly above normal for early April.
Across the Tennessee Valley and the Carolinas, temperatures will return to and hover in the 70s late in the week.
"But, even though New England will remain close to average, relative to most other areas early this week, New England will be the last to warm up late this week," according to AccuWeather senior meteorologist Alex Sosnowski.
"It may take until the weekend before some milder air works in from the west and south," he added.
The warmup could be delayed in New York City for a bit as well.
Exactly how long the warmth sticks around in the East, once it arrives, will be determined on if any storms cross the region and pull more cool air down from Canada.