JUNE SHOWERS BRING...
June is the official start of meteorological summer. Aside from the warmth the month typically brings, it's a period that tends to be be wet, especially with the increase in instability that drives thunderstorms. As you can see below, June is the second wettest month of the year in the Quad Cities with average rainfall of 4.73 inches. That's nearly 1.20" of rain per week.
The system that came through Sunday and Monday produced it's heaviest rains in the NW third of my area where amounts of 1/2 to 1.50 inches were noted. Some local spots such as Independence and Marengo had over 2 inches. The area near and west of I-380 saw the lions share of the rain.
Even larger totals of 3-4 inches fell just NW of Des Moines.
Since the end of May, my northwestern counties in Iowa have been the focus for the heaviest showers and storms. Another pocket of very heavy rain should also be noted in WC Illinois down around Macomb.
It looks as though rain will be no stranger to the region this week as another disturbance gets set to impact the central Midwest Wednesday. Before it arrives, Tuesday will a dry day with weak ridging producing clearing skies in the morning and afternoon highs in the mid to upper 70s. Humidity will be lower as well making for a fine afternoon.
Clouds are back on the increase Tuesday night and by morning and much of the day Wednesday, scattered showers and a few thunderstorms will roam the area. For now, there are some placement issues regarding the location of the more substantial rains. The evolution of Monday nights storms will have a lot to say about how things turn out but some generous rains are possible in most areas if current trends hold. That however, is conditional on outflow boundaries and mesoscale details that are yet to be resolved. Here's what the EURO depicts for rainfall Wednesday.
The GFS is even more bullish showing amounts like this,.
Temperatures Wednesday could be held in the 60s, especially in the NE half where clouds and precipitation prevail much of the day. The GFS shows this for highs.
With that system gone, Thursday appears to be a nice day with sunshine returning and highs getting back into the mid to upper 70s areawide.
That break doesn't last long as the next disturbance in this active pattern arrives from the northwest Friday. A band of showers and storms looks to track southeast along a boundary from SW Iowa into Missouri. That's the type of set-up that brings lots of clouds and wet weather to the cool sector which is where we'll reside. Again, it's a bit early to determine where the best forcing takes shape but another nice band of 1/2 to 1 inch rains is possible somewhere. This is the 5 day rain totals projected by the Weather Prediction Center ending Saturday morning.
That's quite a bit different than the operational GFS which is significantly wetter in eastern Iowa.
That leads us to the weekend which up until today has been rain free on previous guidance. The EURO still maintains that course Saturday but the GFS brings in another fast moving short wave Saturday afternoon that kicks up more showers and storms before exiting Sunday. The slower EURO brings in the rain later Saturday night and keeps it around much of Sunday. I'm not sold on any solution yet with so much energy in the pattern. With two systems to go before this one even arrives, I'll just mention there is quite a bit of uncertainty as to how the weekend evolves leading to a low confidence forecast at this point in the game.
I will close with what could be a shot of very warm mid-summer like conditions around June 17-21st. The EURO develops a potent heat dome that centers itself over the Midwest during that period. This is a very hot sultry look at 500mb if indeed it verifies. I won't say this is a hard trend just yet as the GFS which had a similar look, backed off some on it's latest run. A couple more days of data should confirm where things are headed.
Whatever the GFS says, the EURO depicts highs reaching 100 in SE Iowa and WC Illinois the 19th and 20th of June.
Notice the EURO's change in the June temperature anomalies from week 1 to week 2. A dramatic reversal.
Week 1 (June 6-June 13th).
Week 2 (June 14-June 21st).
The northeastern periphery of the developing heat dome is a known spot for active thunderstorms and what's know as a ring of fire pattern. We often see this set-up at some point in the summer and for those in the line of fire the action can be hot and heavy with very active nocturnal thunderstorms. I fully expect it over some part of the Midwest in the 8-14 day period but the precise location is still in question. I do think the next 2 weeks have the potential to see above normal precipitation. More to come on that.
Meantime, there's plenty of weather on the table this week but Tuesday is one of those days that will not be a problem. Take full advantage of what it has to offer! Roll weather...TS