The weather pattern will remain unsettle for the foreseeable future, especially in the short-range as we continue to track a slow moving storm system which developed early-week over the Central Plains. It’s now Thursday and it has only moved a few hundred miles, now becoming centered over the Midwest. It’s not until the weekend when the storm will finally move into Canada, but impacts will still be felt in parts of the Northeast as late as Monday.
Flooding rains will remain a concern on Thursday, especially in the afternoon and evening. The greatest risk for flooding will span from the Midwest through the southern Mid-Atlantic region as tropical moisture streams in from the Gulf of Mexico associated with the storm delivering the flooding rains to southern Texas. It’s these areas that have experienced an abnormally wet spring, and now that it is summer we are still talking about the risk for flooding and additional rain in the same areas.
This morning, there is a band of mainly light to moderate rain spanning from near the center of low pressure over Iowa and southern Minnesota through the western Ohio River Valley and into the Tennessee River Valley. As the day progresses, this first line of rain will become scattered while developing in thunderstorms. Meanwhile behind this area of convection will be several other lines forming in the warm sector of this storm. It’s these hit or miss thunderstorms that will have to be watched closely because some of them may turn severe. Most storms should remain sub-severe because the environment is only somewhat conducive to produce strong storms. Nonetheless, a few storms may contain damaging winds and small hail from eastern Iowa southward through the Mid-Mississippi River Valley. A tornado or two may even develop. The best chance, which is a low chance at that, for a tornado will be near the triple point in eastern Iowa and northern Illinois.
There will also be a wave of low pressure riding a front across the mid-Atlantic. Now while the day will start off dry, there will be the concern for hit or miss thunderstorms during the latter half of the day south of the Mason-Dixon Line. A few of these storms may turn severe as well. Then overnight, the storms will likely evolve into a steadier band of rain, slowly tracking to the north and east. Localized flooding will be a concern with these heavier round of thunderstorms, which will move into a city like Washington, DC.
On Friday, the low pressure will finally track into the western Ohio River Valley. This will shift the showers and thunderstorms a bit farther to the east, but many areas will experienced another day of rain, unfortunately, and yes, that does mean another day of flash flooding will be possible in the Ohio River Valley and Mid-Atlantic.
If you take a look at the radar on Friday, it will be quite easy to notice the spin, illustrating the rounds or band of showers and storms revolving around the low pressure system. We’ll see the main band of rain and embedded thunder, which will be associated with a warm front, moving into the southern Great Lakes, eastern Ohio Valley, and Mid-Atlantic. Back to the south and west, there will also be rounds of scattered showers and thunderstorms primarily affecting the Ohio and Tennessee River Valleys. A piece of energy that will move through the Gulf Coast states will reinvigorate some of these storms, so there will be the risk for isolated to perhaps scattered severe storms from the ArkLaTex into the northern Gulf Coast states and back up into the Ohio River Valley. Hail and damaging winds will be the main risk with these storms.
Then on Saturday, the activity will shift into the Northeast where many will experience a rather ugly weekend. Low clouds and rounds of rain and thunderstorms will move in a northeastward direction, affecting most of the region during the day. There is some hope that eastern New England stays dry, however. That will not be the case to the west, unfortunately, where there will even be the risk for a few stronger storms in the Mid-Atlantic as an area of moderate wind shear and instability streams in from the south. Localized flash flooding will also remain a threat among the plethora of others.
Scattered showers and storms will also remain in place across parts of the Ohio and Tennessee River Valley, but the day as a whole will feature improved weather conditions compared to the late-week time period. The risk for flooding will also significantly drop as the deepest of atmospheric moisture shifts to the east.
Sunday will be a better day overall for the Northeast. Sure, there will still be scattered showers and storms around, especially in New England, but there will be more in the way of sunshine working into the Mid-Atlantic with only the chance for a brief period or two of rain. Now in New England and parts of New York and Pennsylvania, lower pressures will hang on, keeping showers around.
It’s not until Monday when we can say bon voyage to this storm, a storm that wanted to stay over the US this entire week, being the main driver of the week’s weather. Besides a few lingering showers in northern New England, especially in the morning hours, the rest of the northeastern US will dry out as high pressure builds in from the west. The next chance for rain won’t arrive until as early as Thursday, so a nice period of nicer weather will be in store to begin the new week.
Through Monday night, many areas will have measured a total of at least half an inch of rainfall. There will be a large area of rainfall in excess of one inch as well, including the Central Plains, Midwest, and much of the Mid-Atlantic. Some areas will even receive over two to three inches of rain, which will make for that risk for flooding.