SUMMER TAKES A STEP BACK

Both Monday and Tuesday, the weather around the region was impacted by thunderstorm remnants known as MCV's (mesoscale convective vorticity). Thunderstorms clusters that formed well out of the area Sunday night and Monday night, diminished and died with the lack of heating. Even in death, the energy (and vorticity remained), along with a pocket of rain cooled air aloft. During the peak heating of both Monday and Tuesday afternoon, these remnants were enough to be the genesis of new thunderstorm development in the afternoon and evening as they pushed through.

Monday's storms hit parts of Delaware, Dubuque, and Jo Davies County hard with 2-3 inch rains and flash flooding. Tuesday, it was Eastern Clinton and SE Jackson Counties that rang the bell with additional totals of 2–3 inches plus. These are the 48-hour rainfall estimates ending Tuesday evening.

The amounts above do not include what fell in another line of storms that came through the region during the overnight hours along a cold front. Some additional downpours fell in parts of eastern Iowa but once again, with sunset and the decreased instability generated, the storms rapidly decreased in strength as they entered eastern Iowa and entered western Illinois. It looks to me like rain from this overnight event will be minimal in most cases. The satellite late Tuesday evening shows the day's first round of storms, along with the second ones still approaching in central Iowa.

Specifically, the line of clouds in central Iowa represents the front that clears the region by Wednesday morning. Temperatures will not be significantly cooler Wednesday, but dew points go from near 70 Tuesday evening to the mid 50s by noon Wednesday (much less humidity). Most of the day sees ample sunshine, with highs in the upper 70s north to the low 80s far south. Later in the day and into Wednesday evening, another cold front enters the picture, and this one is the real deal. Not only will temperatures cool going forward, they will go below normal for several days starting Thursday. Additionally, the front could produce another broken round of showers and storms late Wednesday or Wednesday evening.

The GFS meteorgram show 8 consecutive days in the 70s in the Quad Cities.

The EURO is not quite as cool but indicates 7 consecutive days with highs in the 70s. That's a feat not easily accomplished with the sun about as direct and strong as it gets.

These are the 7-day temperature departures on the GFS for the period June 5-12th.

The 6-10 day temperature outlook June 10-14th from the Climate Prediction Center.

One positive of the developing NW flow is that it constricts moisture. Precipitation in the period June 10-14 is actually shown to be below normal. That is a good thing.

Even though precipitation is lighter, it does not mean we won't see any. With the cool cyclonic flow, there will be instability aloft and scattered showers, which are shown on the GFS Thursday afternoon in the north. They appear once again Saturday, as well as parts of Sunday and Monday in most areas. Again, these appear to be quite light, as well as hit-and-miss and brief in nature. There will be plenty of dry hours, but at least for now a low threat of spotty showers exists at some point every day through Monday of next week.

The actual cool-down begins to be felt Thursday with scattered clouds and a few showers in the NE, holding highs there in the upper 60s with a brisk wind. Further south, readings should be warmer in the low to mid 70s far south. After that, 70s run the table in the south into much of next week, with at least 2-3 more days in the 60s likely across the north.

Anyway, we get one more pretty good day today before summer steps away for about a week. Roll weather...TS