After a dry beginning to the week, we only expect rain, rain, and more rain for the rest of it. Flash flooding threatens the Upper Mississippi and Ohio Valleys, there’s an enhanced risk for severe weather in TX and LA, and all of this rainy mess will soon arrive in the Northeast as well. Unfortunately, this weekend most will continue to see more rain.
Welcome to the Wednesday edition of your Morning Briefing. Let’s begin.
Flash Flood Watches Across Upper Mississippi and Ohio River Valleys:
- Today and tomorrow, a cold front associated with a surface low sitting over Lake Huron will most eastward today and tomorrow. Ahead of this front will be storms and precip as it moves across the country.
- 1-2 inches is expected throughout the region, from the Southern Plains to the Lower Great Lakes. Higher totals closer to 4 inches are expected from eastern TX and northern LA to southern OH along the Mississippi and Ohio Rivers.
- Flood watches are in effect for the Upper Mississippi and Ohio Valleys. Flash flooding is also possible as rivers overflow from excessive rainfall.
For the rest of the week, all eyes will be on the system that’s been slowly developing from a shortwave trough. Currently, this shortwave trough dips south to sit aloft over the 4 Corners. Its associated surface front currently begins at its surface low over Lake Huron and swings all the way southwest into northern central TX. As this cold front swings toward the east, it will interact with the warm, moist air ahead of it. Moisture from the Gulf has been ejected into the Southwest by a high pressure circulation earlier this week, and now this moisture will come into play as it provides the means for possibly excessive rainfall. The highest rainfall will span from eastern TX and northern LA all the way to southern OH, following the Mississippi and Ohio Rivers. The greatest chance for flooding is also along these rivers. Most places in eastern central TX are just about above their monthly average, and some are close to beating their October rainfall record. Rain from this one last Halloween storm could push them over the edge.
Enhanced Severe Risk for TX and LA Today:
- The same cold front that will bring flooding to the Mississippi and Ohio Valleys will also bring an enhanced risk for parts of TX and LA today, meaning that there is a high risk for severe storm development.
- Within these severe storms there is also a high risk for damaging hail and strong winds due to deep instability.
- Areas with a slight and marginal risk also have a chance of severe storm development, but storms are not expected to become as damaging.
This cold front will be causing all sorts of trouble at the end of this week. In addition to flooding, this front is expected to be accompanied by developing storm cells, some severe. An enhanced risk for severe development is placed over eastern central TX and western LA. An enhanced threat of severe weather means that damaging hail and winds are possible within developing severe storms. It also means that the chance for severe storm development is higher than in the surrounding areas. Deep forcing, along with daytime heating in the late morning and into early afternoon, will keep this risk active throughout the day, only subsiding once the front has finished passing. Squall line and tornado formation are also possible with the passage of this cold front. In other areas under slight and marginal risk, severe storm development is also possible (but less so) and will most likely be less damaging.
Heavy Rains to Continue in the Northeast:
- This same system will cause trouble for the Northeast later this week, with moderate rain of 1-2 inches possible.
- As this system develops a low pressure center in the south, it will follow flow into the Northeast, causing rain and possible thunderstorms Thursday night into Friday.
- Another developing low pressure center will be trailing right behind this one, continuing our wet weather well into the weekend.
This same system will make its way to the Northeast later on in the week. As this cold front continues to slowly move eastward today, tomorrow, and Friday, it will bring its surface circulation along with it. At the leading edge of this circulation is rising motion, which will continue to give us precip and a few thunderstorms. By later tonight, this rainy system in TX will have developed another low pressure center at the surface. Following flow from the jet, this low pressure center will end up in the Northeast by late Thursday/early Friday. With it, a trailing cold front, remnant from the one currently draped across the country, will bring heavy rains and a few pop-up thunderstorms. Following right at its tail will be another low pressure center this weekend starting midday Saturday.
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Also remember to lookout for The Sunday Storm this upcoming Sunday evening as well as Five Things to Watch This Week on Monday.