So far this week severe storms have been very active, and the trend will continue for the end of this week, although the worst of these storms may be behind us now. Nonetheless, additional intense thunderstorms containing large hail, damaging winds, and tornadoes will be in the cards, especially on Thursday.
On Thursday, over 70 million people in the United States will be at risk for strong to severe thunderstorms, spanning from the eastern Southern Plains up through the Great Lakes and into New England. The best risk for the worst of these storms will be found in portions of the Central Plains and Midwest, specifically including eastern Kansas, northeastern Oklahoma, and western Missouri. All of the ingredients going into Thursday’s severe weather threat will be present, but they will not all be at their full potential. In terms of winds, there will be both a strong jet stream and low-level jet that will overlap over the area where the worst of the thunderstorms will develop. Temperatures and moisture will also be at conducive levels for storms of this magnitude, but a potential limiting factor will be the instability, or Convective Available Potential Energy (CAPE). CAPE values will eternally be between 500 and 2000 J/kg, which is on the low to moderate spectrum of the scale.
Now let’s talk timing: it’s going to be a very messy radar picture Thursday morning. Lines of storms will be moving through the western Ohio River Valley, potentially containing damaging winds. There will also be a couple lines of showers and storms in the Southern Plains, which will peak in intensity midday. Scattered showers and thunderstorms will also be found in the Central Plains and Lower Midwest. Then in the afternoon, that line of showers and storms in central Texas will track to the north and east while weakening into eastern Oklahoma and northern and western Arkansas. Rounds of showers and thunderstorms will continue to move from east to west in the Ohio River Valley, mainly north of the river. Much of the Midwest will also experience scattered thunderstorms, some of which will be severe. By the evening, however, upper-level forcing will initiate the development of thunderstorms along a dry line in extreme-eastern Kansas. These storms will track into Missouri and possibly southern Iowa and northern Illinois overnight. The best chance for tornadoes from these storms will be in eastern Kansas and western Missouri. There is also a severe threat in the Northeast Thursday afternoon and evening as scattered showers and thunderstorms move through from the west, mainly away from these coast. Some of these storms may actually be supercells, and the environment may be conducive for a few tornadoes.
Then overnight Thursday, much of the activity will quiet down, but an incoming piece of energy associated with the upper-level low over the West will allow for the develop of rain and thunderstorms Friday morning in the Rio Grande Valley. Scattered showers and thunderstorms will be found farther north and east into the ArkLaTex, while a widespread batch of rain with embedded thunderstorms moves through the Great Lakes region.
On Friday, the threat for severe weather will continue, although it will be on the lower side of the scale. Severe weather will be possible in the Rio Grande Valley of Texas and eastern Texas as well as from the Ohio River Valley through northern New England. We think the best chance for strong storms with primarily a damaging wind threat will be in the Northeast where the strongest of the jet stream and low-level jet winds will be found. Winds at the jet stream level will likely exceed 160 mph. CAPE will be on the lower end once again, so that will put on a cap on the potential strength of these thunderstorms.
In terms of timing, a widespread area of rain and thunderstorms will develop across a large area of Texas during the morning hours. There will also be a weak line of rain and thunderstorms draped through the Ohio Valley down through the Mid-Mississippi Valley. Showers and thunderstorms will be moving in from west to east through the Northeast as well. Then during the afternoon, a line of thunderstorms may develop north of the Ohio River. Some of the activity in the Northeast will dissipate, but hit or miss thunderstorms will continue. Even an isolated tornado may develop. Now in Texas, a line of storms may form, spanning from the ArkLaTex through the Rio Grande Valley followed by the large batch of light rain. This line may contain damaging winds.
On Saturday, the severe weather risk will come to an end with the rain and thunderstorms dissipating in the Southern Plains and Northeast. However, showers will be moving through the Tennessee Valley and the Mid-Atlantic on Saturday. Those showers will stick around into Sunday for the Mid-Atlantic while moving into southern New England.
Some areas through Saturday will experience heavy rain. The highest totals will be in the Midwest, Great Lakes, and Texas. There is a drought in a large area of Texas, so this heavy rainfall will be great for the land. Even an extreme drought is currently plaguing portions of the Rio Grande Valley. In Del Rio, Texas, 4.53 inches of rain typically falls January 1st through May 1st, but this year only 0.33 inches of rain has fallen. Some locations will likely receive over two or three inches of much-needed rain.