It’s been a rather cool April but big changes are beginning thanks to a pattern change. This April, and really much of this past winter, has featured a trough or dip in the jet stream over the East while a ridge or rise in the jet stream has been situated over the West. This trough has allowed for significantly below average temperatures across the Midwest and Northern Plains so far this month. The complete opposite will be happening this week as we welcome the month of May with a trough digging into the West, which will bring days of severe weather to the Plains, while summer-like heat under the ridge is found in the East.
This Sunday, above average temperatures will be felt across the Central US as well as in the Four Corners States. Temperatures will mainly be up to 10 degrees above average, but the Northern and Central Plains will be even warmer with highs as much as 25 degrees above normal. A couple locations in the Front Range of Colorado are even forecast to break record highs due to high temperatures in the 80s. Meanwhile in the eastern third of the US, temperatures will remain below average. Highs will be up to 30 degrees below average in the Northeast due to a cut-off low while temperatures are more seasonable in the Southeast. Actual high temperatures in this region will generally be in the 70s. Farther south into Florida, highs will be in the 80s, which is about average for this time of the year.
Now as the week progresses, the heat will gradually shift to the east. By Thursday and Friday, the heat will peak in intensity across the Northeast. Under the ridge of high pressure over the East will be a strong, surface high. Once that high pressure moves to the east of your location, that will allow for the warmer temperatures and higher dew points (moisture) to surge in from the south. On Monday, the high pressure will be centered over the Southeast. That will allow for above average temperatures to move into much of the South up through the Great Lakes. Unfortunately, it will remain on the cool side for the East Coast due to a northerly wind. In terms of the warmth, a very large region will experience highs 10 to 20 degrees above average across the Northern and Central Plains and the Upper Midwest. Temperatures will be more seasonable down toward the Gulf Coast.
Finally by Tuesday, the high pressure will begin to move offshore, allowing for the above average temperatures to move toward the East Coast. From the Front Range of Colorado through the East Coast of the US, warmer than normal high temperatures are forecast. The only locations east of the Rockies that will experience the cooler than normal weather will be in the Dakotas due to the passage of a cold front as well as in Florida. The warmest of temperatures relative to average where highs will be up to 10 to 25 degrees above normal will be found from the Texas Panhandle through the Great Lakes region. Much of the South up through the Northeast will experience highs generally 5 to 10 degrees above normal.
That will change beginning Wednesday as the higher temperature anamolies reach the Northeast. The surface high pressure will evolve into what is known as a ‘Bermuda High.’ This kind of high pressure is more common in the summer months, and is often responsible for the intense heat waves along the East Coast. Most areas won’t hit the 90 degree mark, but widespread highs in the 80s are expected. So on Wednesday, temperatures will be 15 to 25 degrees above normal for most of the Northeast and Mid-Atlantic. Temperatures will remain over 10 degrees above average from the Texas Panhandle through the Great Lakes region. It will also warm up across the South while warmer air returns to the Northern Plains. In terms of actual high temperatures, much of the South, Ohio Valley, and East Coast will be in the 80s. Portions of Texas will get into the 90s. It will be more comfortable further north with high temperatures in the 60s and 70s in the Midwest and Northern and Central Plains.
On Thursday, it will be a very similar day as Wednesday with highs up to 25 degrees above average in the Northeast, which translates to widespread highs in the 80s. Some locations in the I-95 corridor will likely hit 90 degrees. There will also be an increase in humidity due to the southerly flow, so it will definitely be feeling like summer by the end of the week. The remainder of the East will generally experience highs 5 to 15 degrees above normal, or actual high temperatures ranging from the 60s to 80s. It’s also worth noting that the Northwest will be warming back up as a new ridge works into that region.
By Friday, the heat will likely peak in the Northeast, especially for the I-95 corridor while a cold front brings thunderstorms to the interior Northeast and Great Lakes regions. Highs near the coast in the Northeast will be up to 25 degrees above average, again. Highs across the remainder of the East will be 2 to 10 degrees above average.
Next weekend will not feature any more intense heat. Instead, temperatures will be very seasonable with highs right around normal. The warmest of temperatures relative to average will be found in the Southwest.