TOOLING DOWN SUMMER'S HIGHWAY...
We're coming down the stretch of that long winding road known as summer. Yet, while September is in sight, there's no sign our steamy and active weather pattern is going to break down anytime soon. That means it's game on for muggy days and occasional periods of showers and thunderstorms.
The overall set-up was established Sunday and in the last 3 days, some areas have seen more rain they did in the previous 2 months. Here you can see the rain totals over that period ending Wednesday morning at 7:00 AM. Some areas southeast of the Quad Cities have seen more thanks to storms late Wednesday afternoon.
What's really great to see is that much of the heavier rain fell right where it was needed most, that being areas that were experiencing severe to extreme drought.
Here's some more localized reports of rain that fell late Tuesday through early Wednesday.
These are Doppler estimates of additional rain the fell in the southeast Wednesday afternoon and evening.
As I'm sure you're tired of hearing me say, forecasting the timing, coverage, and intensity of rains in a pattern such as this is extremely difficult beyond 24 hours because storms (or lack of storms) the previous day can modify the environment with cold pools and outflow boundaries. Our models struggle to identify those features until the process is complete. There are tell tale signs to look for regarding upper air disturbances and the placement of fronts and moisture, unfortunately that often leaves quite a bit of room for error so keep that little tidbit in mind going forward.
The next rain threat is seen on models Thursday night. Initiation is consistently shown in NW Iowa near the Minnesota border early Thursday afternoon. From there the complex builds and surges southeast towards my area. It's here that models diverge in their solutions. Some drive the storms almost straight south barely touching my counties in eastern Iowa. Others are more easterly with the movement and spread the storms into the northern third to half of my area. The other camp is more of an east southeast trajectory that encompasses all of my area. I really can't say for sure how it plays out but I do like the idea of a southeast turn so it's my belief that the greatest chances for significant rain in this scenario would overall be in my Iowa counties. The further west you go from the Mississippi the better the odds for rain. To give you and idea of all the options I have to chose from, here's what various models are showing for rain totals. They are all over the board and this is just 24 hours away. Just a brutal pattern to forecast. Clearly, the latest trends certainly keep the brunt of the heavier rain just west or north of my area not only with this system, but with those to follow through the weekend. I'm disappointed that rain totals look lower than they did the past couple of days.
The 3k NAM (a complete miss)
The 12K NAM
The Weather Prediction Center blend
However this plays out, there should be enough sunshine Thursday to allow temperatures to spike into the upper 80s to near 90 across the south. With dew points well into the 70s heat index values of 90-96 would result from north to south.
That creates plenty of instability and that is reflected in cape values which would be sufficient for severe storms, especially in Iowa.
The Storm Prediction Center has an enhanced to slight risk outlook for strong storms late in the day and evening. I suspect most of the stronger storms will be out to the west of my area.
Friday and Saturday actually look to be fairly quiet days as the primary forcing shifts northward into the upper Midwest. That's going to mean more in the way of muggy weather but less in the way of rain chances which are lower, (30 percent or less) in my area.
Sunday, while still warm and sticky rain chances will go up again in the afternoon as a cool front approaches from the northwest. The hope was that the front would get far enough south that rain chances would be eliminated early next week but that looks questionable today, especially with the remnants of a hurricane down south blocking the pattern. If nothing else, the humidity will go down some, especially in my northern counties.
Speaking of that hurricane, that could be a big problem for the coastal areas of NE Texas or Louisiana. Early indications are it could be a major, category 3+. The latest GFS has it coming in just SW of New Orleans Monday night or Tuesday of next week.
That's all I have for you tonight. Make it a stellar day and roll weather...TS