THE LOOK AND FEEL OF SUMMER

It was a long time coming, but the warmth and humidity of summer put the squeeze play on the area for the first time this summer. Highs in the 80s and dew points near 70 were the catalyst for a good case of the muggies. I finally had to turn on the AC.

Something else of consequence were strong thunderstorms that scraped my northern counties up around HWY 20. High CAPE (instability), was evident in all areas due to water vapor levels that peaked near 1.50 inches, high enough to reach the 90th percentile. Despite all the ammunition for thunderstorms, the only region with enough forcing to see them was the far north. There, the remnants of another storm complex called an MCV (mesoscale convective vortex) acted as the seed to develop another cluster from roughly HWY 20 north. The late afternoon storms devoured the deep moisture and spit it out in the form of heavy rain. Totals of 2–3 inches in an hour or less produced flash flooding in parts of Delaware, Dubuque, and Jo Daviess Counties. Along with a Flash Flood Warning, Severe Thunderstorms Warnings were also issued for that region.

Below, you can see the Doppler estimates of where the heavy rains occurred. The bulk of my area was sticky but dry. However, when the storms came through here in Dubuque, the skies really opened up. I could barely see across the street for a time. I've now had about 20 inches of rain at my place in the past 3 months and a break would be welcome here!

Bobby Ellison took this picture along Key Way Drive in Dubuque.

Kendra Cross took this near 24th and White street, Dubuque.

NOT THE END OF STORMY WEATHER

Before this batch of wet and potentially stormy weather bids us farewell, another MCV approaching from the south, along with a strong cold front later Tuesday night, brings the threat of additional showers and storms. Dew points in the upper 60s to low 70s will fuel a heavy rain threat where storms do occur. A strong storm or two is likely, with CAPE possibly reaching 1,500 to 2,500 j/kg Tuesday afternoon.

The MCV round of storms Tuesday afternoon has the higher potential for heavy rains and any severe weather as it lifts NE. Before any storms arrive, temperatures have a good chance of reaching into the upper 70s to low 80s.

The simulated radar shows this on the 3K NAM late in the afternoon.

Following the afternoon storms, there looks to be a few hours break before another batch arrives late in the evening or overnight along the approaching cool front. The simulated radar around midnight shows that line moving into eastern Iowa.

The late night arrival of the front and the reduction in instability from the first round of storms should keep this batch under severe limits. It's also likely the line diminishes the further east it gets, as instability weakens even further. Between the two rain opportunities, models suggest this for rain totals through Tuesday night.

The EURO

The GFS

The 3k NAM

The HRRR

Finally, the cold front passes Wednesday, dramatically lowering moisture levels and cooling temperatures. The resulting NW flow will create a rather strong cyclonic flow. That should produce breezy conditions and may spark some instability showers due to chilly air aloft and strong lapse rates. It's Wednesday night and again Thursday afternoon when these showers could be scattered around. They will be significantly lighter than what is seen Tuesday.

Temperatures remain mild Wednesday in the range of 75-80, before cooling to 70-75 Thursday, and finally 65-70 Friday.

Generally dry weather prevails Thursday right on through the weekend. Pleasant days and cool nights will be the rule into early next week.

I have noticed both the EURO and GFS indicating a building central U.S. ridge in the long term near and beyond June 15th.

Notice the heat that builds into Kansas and southern Nebraska. Even SW Iowa hits 95. It will be interesting to see how far east the heat gets. I could certainly see the makings of our first sustained heat of the summer. If the heat holds roughly where it's shown, that could also establish a ring of fire pattern that is known to produce active thunderstorms, some strong with heavy rain and MCS potential. It's a tad early to get on the bandwagon, but the climatology fits, and the look is there, at least today.

That is all I have for now as we face what looks to be a busy 24 hours of weather. Until next time, roll weather...TS