UNSETTLED START TO THE WEEKEND...
Our weather got back on track Wednesday as sunshine and very pleasant conditions returned to the central Midwest. All signs point to another dry day Thursday but there will be some clouds moving into the picture, especially during the afternoon. Temperatures promise to be comfortable once again starting in the 50s and ending in the upper 70s to low 80s.
Thursday night the focus turns to our next weather maker which will get the weekend off to an unsettled start Friday and at least parts of Saturday. You can see the disturbance getting organized out to the west.
In the upper levels the ridge that brought us the fine weather Wednesday is forced off the the east and by Friday night a trough is shown crossing the Midwest,
The best forcing remains to the north but there will be a decent southerly flow and that will allow some moisture to works its way in the area setting the stage for scattered showers and maybe a few storms late Thursday night but more likely Friday. Notice how water vapor increases from Wednesday to Friday morning.
Wednesday mid-day water vapor.
Friday mid-morning water vapor.
Overall though, the wave is weak, forcing is limited, and cape (convective available potential energy) is low due to a lack of heating. As a result, rain is likely going to be more stratiform and light (perhaps moderate in a few spots). Models do indicate a weak warm front cutting across my central counties Friday that enhances warm advection. This region of frontogenesis may produce a narrow band of slightly heavier rainfall somewhere if elevated storms can form as indicated. In the end, the lack of instability should keep any storms below severe limits and rain light in the majority of my area. I will fine tune that in the next 24-48 hours.
After this passes late Friday another wave may ignite a few more showers Saturday but there's not much agreement on that prospect at this time other than to say the heavier rains from this disturbance should remain to the south, perhaps just clipping my far southern counties. Here's what several models show for total rain Friday through Saturday.
The GFS
The EURO
The 3k NAM
The 12K NAM
THE WPC blend
Friday and Saturday temperatures will be dependent on rain and cloud cover. With rain chances greatest on Friday that should be the coolest day with highs potentially holding in the low 70s (mid 70s at best). Saturday should see slight improvement with readings generally in the mid 70s.
By Sunday northwest flow is reestablished sending drier air into the Midwest and clearing out the skies. Sunday and Monday should both be fine days with highs 75-80.
With that, I will sign off as the September stars twinkle overhead. Hard to believe summer is behind us. I can sure tell the difference in the shorter days. Time to start appreciating the warm temperatures as the annual march towards winter is well underway. Roll weather...TS
