Friday, June 19, 2015 4:26 PM

Bill Will Bring Flooding To Many, Southeast Heat Continues

Matthew Holliday

Bill is still a very healthy-looking storm with the mid to upper-level atmosphere remaining favorable, allowing the storm to maintain itself fairly well over land. As expected, the flooding situation became pretty serious across parts of Texas and Oklahoma, and parts of the mid Mississippi Valley have already gotten and will continue to get some heavy rainfall from this system, too. Anytime you throw a tropical system into the mid-latitudes, the forecasting period becomes challenging, and it doesn’t help that the model guidance is usually off a bit.

Visible Satellite Image Of Bill Over Arkansas/Missouri:

Visible Satellite Bill

Bill Bringing More Flooding Rains; More Heat/Some Storms Expected In Southeast:

As I’ve discussed on the site for several days now, there has been a persistent heat ridge over the Southeastern United States. Because of its position and strength, the air has been very stagnant. When you have a blocking ridge like that over a certain area, that region gets cut off from the main flow, so systems (such as Bill) just go around the ridge. That’s why it’s sometimes referred to as the “ring of fire,” because all of the rain is located on the outskirts of the ridge. The ridge has begun to flatten out over the Southeast and is temporarily weakening, so some of these areas will have a shot at getting some pop-up afternoon and evening storms today and this weekend. In fact, there is a decent microburst threat today across parts of the Southeast. Simply put, microbursts are strong winds (downdrafts) that develop in a storm and push to the surface. Once those winds hit the surface, they spread out and can cause damage.

The remnant precipitation from Bill may end up moving farther to the south than I originally anticipated but not by much. However, this can be the difference between someone getting a lot of rainfall and not. As I stated, the position of the ridge and how much is breaks down/flattens out is key to how far to the south this storm is able to track. Since Bill has probably had more of an effect on the overall pattern, northern parts of the Tennessee Valley could get more rain than originally forecasted, with places like Kentucky, lower Illinois, lower Indiana, lower Ohio getting heavy rain also. The rain will eventually spread eastward into the Mid-Atlantic states. This system will trek right along a stalled frontal boundary.

WPC’s 2-Day Rainfall Forecast Based On Latest Model Guidance:

2-Day Rainfall Map

Will The Heat Ever End Across The Southeastern U.S.?

Many of you across the Southeast are probably wondering if this heat is going to let up, and the answer is no, at least for the next week to ten days. The heat ridge is going to begin to reestablish itself next week, which could bring temperatures that could challenge or break records. As I have been warning for months now, many areas are going to really get some of that summer heat this year, and I was particularly adamant about that in my June/summer forecast. The big wildcard right now is whether or not this ridge will break down once we get into July. I believe the Northeast definitely has some cooler weather on the way (even this month), and forecast model guidance strongly suggests that cooler temperatures will dig fairly far into the Southeast towards July, with the exception maybe being right along the southern Gulf coast states and Florida. This would be right on schedule with my seasonal forecast, if that occurs. We have plenty of time to discuss that though. Right now, we’ll focus on the coming heat.

European Model Shows Ridge Building Back Over Southeast Next Week:

Ridge Builds Back In

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