We had an overnight low of 71° after a high of 90° yesterday. Humidity levels are on the increase making the misery index outside moving into the uncomfortable range. The big question today is will we see some rain? There are some showers moving through Indiana from south to north, though not substantial the green blob on the radar does bring the hope of things to come.
According to the NWS southern Michigan has a 40% chance of rain mainly this afternoon mainly from popup showers and storms this increases to 60% tomorrow and 70% on Wednesday. Before we do our happy dance we have to keep in mind the NWS computer forecasts have been bullish on rain for several weeks.
We do have the ingredients in place to make rain possible, maybe even our first summer storms. Chances appear good to me much of which is explained in the forecast discussion below.
- Scattered Showers / Locally heavy downpours most of week We have forecasting the closed upper low from Texas to slowly track into our area, for at least a week now. We have seen saying you should expect scattered showers and isolated thunderstorms from Mon through Wednesday last week. More recently we expanded that to go into Friday. The issues are facing is deep tropical moisture, very low vertical wind shear, model sounding that look nearly saturated to near 300 mb, plus narrow cape to near 300 mb. This will likely continue through most of this week. What this means for us is locally heavy rainfall but no severe storms. We, at this point can not pinpoint were exactly this will happen or when but this does seem more likely than not. As you can read below, this system will be around most of this week, so each day it will be the same thing really. Deep layered clouds, scattered shower, isolated thunderstorms and locally heavy rainfall (mostly in the mid afternoon and early evening each day). The glitch of course is that there is no surface reflection of this upper level system. The center of the upper low gets to near southern Lake Michigan, northern IN and northeast IL in the Tuesday to Wednesday time frame. By Thursday it is likely be be over OH. Due to deepening west coast trough and developing east coast trough, this system gets stuck! A REX block (close upper level high over a close upper level low) actually develops by later Tuesday into Wednesday. This system has deep tropical moisture with it. Precipitable water values are forecast to be in the 1.8 inch to 2.0 inch range of most of our CWA by mid afternoon. With the system stalled near us most of this week, that will only slowly diminish as it slowly get rained out over the next 5 days. - Brief spike in temperatures this coming weekend Later this week, a strong lead wave, coming out the Pacific system, will be heading in our direction. By Friday we should see some shortwave ridging ahead of it. That will push the current system out of the picture. However it is a dynamic system and will likely bring more convection to this area later Friday or Saturday. The shortwave ridging will bring a surge of warm to maybe even hot temperature in the Friday/Saturday time frame. I could see some highs in the 90s again. - It may turn much cooler early next week What happens next is this dynamic system will try to create a fairly impressive deep trough over the central Great Lake by early in the following week. If what actually happens is anything close to the ECMWF (past 2 days of model runs) operational forecast, trust me, it will get much cooler than the current forecast models show. I could see highs only in the 70s Monday or Tuesday if the ECMWF operational forecast is correct. The GFS is heading it`s forecast solutions in the direction of the ECMWF and Canadian is very much like the ECMWF. That being so, we get a break from the warm/humid conditions early next week. There would be showers around through if this all works out that way. The bottom line to all of this is expect a lot of clouds, occasional showers and warm temperatures into at least Saturday.