Rounds of rain as well as some severe thunderstorms will be the story this weekend. Two upper-level troughs, one over the Midwest and another over the Southwest, will both lift off to the north and east. This will bring more rain showers and thunderstorms to the Eastern US.
On Friday, the surface low pressure associated with the first upper-level trough will bring rain and some thunderstorms to portions of the Great Lakes region during the morning hours. Generally Wisconsin and Michigan will be the most affected. In the afternoon, a line or two of thunderstorms are expected to develop from the Ohio River Valley up through the interior Northeast. These lines of storms will move in an eastward direction, containing gusts of up to 60 mph. If a thunderstorm is producing at least winds of 58 mph, that would warrant a Severe Thunderstorm Warning. This forecast sounding for central New York this evening highlights a favorable environment for tornadoes. High shear will be present, but instability will be low, which may be a limiting factor for today’s severe weather threat.
During the evening, the first line of rain and thunderstorms will work into the I-95 corridor, including Boston, New York City, Philadelphia, and Washington, DC. Storms are not expected to be severe, due to the lower amounts of humidity and instability, but there will definitely be an increase in wind as the precipitation moves through. Overnight, rounds of showers will work through portions of the Ohio River Valley, especially in Kentucky, and the Mid-Atlantic. Most of these showers will be light.
Farther south and west from the second upper trough, there will be slow-moving rain and thunderstorms slowly working south and east through the duration of the day from central Texas to southern and eastern Texas by the evening. Meanwhile these storms will be weakening and will become more scattered. Nonetheless, a few strong to severe thunderstorms will bring the possibility of damaging winds and small hail. Showers and thunderstorms will also affect the ArkLaTex and Mid-Mississippi River Valley Friday. Friday night, scattered showers and thunderstorms will continue for parts of the eastern Southern Plains, but the most widespread activity will be found in low and Mid-Mississippi and Tennessee River Valleys.
On Saturday, the first upper-trough will lift off into Canada, allowing for the second disturbance to primarily bring terrible weather to portions of the East. High pressure, which was responsible for this record, along with late-week heat in the Northeast will move farther offshore, allowing for rain to reach the East Coast. A widespread batch of rain with embedded thunder will persist Low and Mid-Mississippi and Tennessee River Valleys. There will be some pockets of heavier rain but the majority of it will be light. Later on in the day, this rain shield will track north and east into the Ohio Valley, again mainly south of the river, as well as into parts of the Mid-Atlantic. A few showers and thunderstorms will also sneak into the Southeast. A potential tropical cyclone, which will be very weak, may swing in a few showers and thunderstorms into central and South Florida on both Saturday and Sunday. Much of the South will then dry out Saturday night while the majority of activity works into the Northeast. This mainly includes the Mid-Atlantic and eastern Ohio River Valley.
For Sunday, showers will persist across the Mid-Atlantic while entering into southern New England. A few showers will also be possible in the Carolinas. Meanwhile back off to the north and west, a cold front will bring in another round of showers from the Midwest through the Ohio River Valley and into the interior Northeast. This will be a broken line of rain showers, so Sunday will definitely not be a washout of a day for these locations. By Sunday night, the weather across the Eastern US will rapidly improve with clearing skies and seasonably cool conditions. A few lingering showers may be present in the Northeast.
Now looking ahead to the start of next week, a couple mid-level lows will bring in another rounds of light, scattered showers to parts of the Southeast and Tennessee Valley. Showers will also return to the Northern and Central Plains and Midwest, but thankfully no severe weather is expected.