The ingredients are coming together for two rain events that will bring much of the region a good soaking between now and Sunday morning. The first event is underway and after a mid-day lull could be capped with some late afternoon and evening thunderstorms in the southeast half of the area.
SPC has a slight risk outlook for strong storms in SE IOWA along with much of Illinois and MIssouri
The strength of the storms and where they fire will be determined by a warm front that will slowly advance northward during the day. It looks to align closely with I-80 by late afternoon. The 3k NAM shows temperatures in SE Iowa and WC Illinois reaching the low to mid 70s.
With dew points potentially hitting the upper 60s in those areas it will be a warm muggy spring day for a change in that part of my region..
That combination of warmth and moisture builds up some respectable instability with CAPE values up to 2500 J/KG.
That certainly loads the gun as far as strong thunderstorms are concerned. Along the warm front a small tornado threat is possible with any discrete surface based storms that initially develop. If nothing else some gusty winds and hail look very likely. There's a good chance a late day weather watch will be issued in SE Iowa and WC Illinois if the instability the 3k shows is realized. Below is the significant tornado index which is at a level that needs to be monitored, especially near and south of I-80. After all, it is that time of year.
Between the rain that's already fallen overnight and what's to come through Thursday night the 3k NAM has this for totals. Many areas across the southern half of my area could see an inch with a few spots in the 3-5" range where convection is maximized.
Once this system departs, Friday should be a fine day with some sunshine and highs 70 to 75 from north to south.
The break is short as another storm arrives Saturday bringing the threat of more showers and storms into the night. At this point the instability for severe storms seems to stay south of my area. That is not a sure bet however and the evolution of the overall set-up will need to be watched. Whatever happens, the system is well organized with a decent surface low. The overall dynamics should make it another good rain producer. For the 2 systems combined, the EURO has this for total rainfall....proof of wet times ahead.
Sunday cooler air again pays a visit behind the storm with brisk north winds. Assuming low clouds don't further cut back highs, readings may not get much above 60-62. On a brighter note, a much warmer pattern returns Tuesday and those 80 degree highs are still on the table for Wednesday and the remainder of next week. Yea baby.! Roll weather...TS