Strong storm with heavy rain, flash flooding soaks Twin Cities
- Blog Post by: Paul Douglas
- July 12, 2013 - 9:29 PM
A lengthy and powerful storm rolled through the Twin Cities before dawn on Saturday, bringng between 2 and 5 inches of rain. It caused flash flooding in many areas. Both Eden Prairie and Lakeville are unofficially showing among the larger rain totals, around 5 inches.
By Paul Douglas
"There is little chance that meteorologists can solve the mysteries of weather until they gain an understanding of the mutual attraction of rain and weekends" quipped Arnot Sheppard. OK. It SEEMS to rain more on weekends, but that may be perception (more of us outside, at the mercy of the elements).
A 7-year NASA study completed in 2005 showed thunderstorm rains over the southeast USA spiked between Tuesday and Thursday, when man-made pollutants peaked. One theory: smog from weekday commutes seeded clouds, enhancing rainfall and hail. The idea isn't as far-fetched as it sounds. We may be inadvertently nudging not only longer-term climate, but short-term weather. The urban heat island, in addition to prevailing winds around hills & valleys, can do strange things to summer storms.
We dodge a few thunderstorms Saturday - especially morning hours. The sun should make a cameo appearance by afternoon. The best chance of Sunday storms: north/west of the MSP metro.
Welcome to the Dog Day Doldrums of summer. A stagnant pattern boosts the mercury into 90-degree territory Monday into Thursday. ECMWF guidance shows a puff of cooler air by next weekend.
My best advice: go jump in a lake.
Todd's StarTribune Outlook for the Twin Cities and all of Minnesota
SATURDAY: Sticky, few T-storms. Winds: S 10-15 Gusts 25. High: 86
SATURDAY NIGHT: Thunderstorms up north. Low: 71
SUNDAY: Humid. More late day/overnight storms, mainly north. High: 88
MONDAY: Hot sun, still steamy. Isolated PM storms north. Wake-up: 72. High: 90
TUESDAY: Hazy sun. Feels like July. Wake-up: 73. High: 91.
WEDNESDAY: Muggy. Spotty PM thunder chance. Wake-up: 72. High: 89.
THURSDAY: Intervals of sun. Thunder risk increases overnight. Wake-up: 71. High: 91.
FRIDAY: Lingering shower/storm early, then partial clearing and a slight dip in humidity late. Wake-up: 72. High: 82.
Ahh - you've got to appreciate a summer sunset, don't you? The air at this time of the year tends to made up of more water vapor rather than ice crystals, so there will be more puffy cloud appearances rather than looking flat. I snapped this picture on Thursdsay evening just as the sun was going down.
My colleague, Aaron Shaffer, has taken up the sport of wind surfing recently and said that Friday's wind in the Minneapolis was PERFECT! The image below is of Aaron and his teacher, Gene, who is almost 69 years young! Way to go you guys! Regardless if you'll be wind surfing or not, jumping in a lake is probably a good idea at some point over the next week or so with temperatures as warm as they'll be!
Ever since Chantal dropped below tropical storm status last week, she has had a hard time regaining strength as wind shear has been one of her biggest enemies. If you were a tropical wave/hurricane, warm ocean water temperatures and weak winds aloft would be your ally. Strong winds aloft have helped to keep Chantal struggling to find a tropical identity, however, moisture associated with the remnants of Chantal will like find its way into the Lower 48 over the weekend.
Spaghetti Models (hungry yet?)
The graphic below suggest the potential paths that the remnants of Chantal may take over the coming days. It looks like different colored spaghetti noodles doesn't it? The different colored lines represent different weather model solutions.
Look at how much rain some spots have seen over the last 14 days. Radar estimates of rainfall in a few locations east of the Mississippi River suggests rainfall amounts of nearly 6" to 12" or more! No surprise that so many locations have been dealing with flooding lately.
More Rain on the Way...
Unfortunately, folks in the Southeast/Mid-Atlantic region can't catch a break. We've had a tremendous amount of rain over the past couple of weeks and it looks like it will continue through the weekend. Thanks to a stalled front and the remnants of Chantal, some spots could see an additional 1" to 2" or more through PM Sunday. Also note the heavier pocket of rain potential across the Midwest. This is in response to thunderstorm potential, some of which could be strong to severe at points this weekend.
The Storm Prediction Center has issued a SLIGHT RISK of severe weather for parts of the Midwest and High Plains on Saturday and Sunday. This activity will be bubbling up on the periphery of some extreme heat and humidty that will keep the middle part of the country very July-like through the weekend.
Severe Threat Saturday
Severe Threat Sunday
July Heat Dome Continues...
The image below shows the current state of our atmosphere. The white line represents the jet stream or strong upper level winds. This is the dividing line between warm summery air to the south and cooler air to the north. Note how it is once again fairly wiggly. The ridge of high pressure in the west and central part of the country is where our heat is currently sitting (thunderstorms are developing on it's northern periphery) and the trough of low pretty in the Ohio Valley is sitting nearly stationary with rain/thunder on it's eastern flank.
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