Friday, July 22, 2016

Strong Afternoon/Evening Storms Possible Saturday

Thursday Severe Weather Recap

Here's a quick look at all the wind reports across Minnesota and into Wisconsin and the U.P. of Michigan from the squall line that moved through the region early Thursday morning. The top wind report was 83 mph recorded in Hallock, and a 69 mph wind gust was reported at the Duluth airport. You can read more about the squall line Thursday morning from the NWS Duluth office.

Meanwhile, many are without power still across northern Minnesota, but crews are making progress. Read more from the Duluth News Tribune.

Photo: Minnesota DNR

Some Minnesota state parks and recreation areas sustained damage in the storms Thursday. This was a tree down in front of the Jacob V. Brower Visitor Center in Itasca State Park. According to the Minnesota DNR as of earlier on Friday, "Itasca State Park campgrounds are open and most lodging facilities will reopen at 4 p.m. Saturday, July 23. There are still some temporary closures of remote campsites, group camps and lodging facilities. Visitors affected by the closures are being contacted by the DNR.  An emergency crew of about 30 is on-site cutting downed trees, cleaning up debris and making trails passable. The park is gradually opening facilities as areas are being cleared of downed trees and debris.  Check the Itasca State Park page for the most current conditions. Douglas Lodge restaurant will reopen on Saturday. The Jacob V. Brower Visitor Center and Wilderness Drive continue to be closed and Itasca’s phone system is still down."Read more about other state parks and recreation areas damaged in the storm at the Minnesota DNR website. View more damage photos from Itasca State Park on the Minnesota DNR facebook page.

Here was what some of the storm damage looked like in the Hill City area, as captured by NWS Duluth senior meteorologist Amanda Graning.

Meanwhile, not even the NWS Duluth office could escape the storms. NWS Duluth meteorologist Joe Moore shared this picture of a tree snapped in front of the office.

Dew Points Friday Afternoon

Dew Point temperatures at 4 pm Friday. Map: Aeris Weather.

While we were able to mix some drier air in on Friday across the Twin Cities, those across southern Minnesota weren't as lucky. Here were the dew points at 4 pm - it was as high as 80 degrees at the Rochester airport!

July 23-24, 1987 Flooding

This year marks the 29th anniversary of the 1987 flooding across the Twin Cities, which brought much of the metro very heavy rain. The Twin Cities airport picked up 10" of rain over the two days, 9.15" of that falling on the 23rd. That day goes down in history as the wettest day in Twin Cities history. Here's some more information on the heavy rain from climate historian Tom St. Martin that the Minnesota Climatology Working Group posted a few years ago on the 25th anniversary:

"The heaviest rainfall ever officially recorded at a Twin Cities weather station fell between about 1800 hours CDT on 23 July and about 0200 hours CDT on 24 July 1987. During this eight hour interval, observers at the Twin Cities International airport station measured an even ten inches of rain (9.15 inches of which fell in a five hour period). And, although it escaped the worst of the storm, most parts of St. Paul received totals in the five to seven inch range, including 5.47 inches at the St. Paul NWS cooperative station; 5.30 inches at the North St. Paul NWS cooperative station; and 6.03 inches at the compiler's St. Paul Battle Creek area station. In addition to the heavy rainfall, the 23-24 July storm spawned a tornado which first touched down at about 1900 hours CDT near Goose Lake in the northwestern corner of the Twin Cities area. The funnel then moved in a southeasterly direction, causing extensive damage in the Twin Cities suburbs of Maple Grove and Brooklyn Park. Damage in other areas (including St. Paul) was extensive, largely the result of flooded homes and businesses, ruptured storm sewers, and washed out or inundated streets and highways. Two flood related deaths were reported and property damage was estimated to be in excess of $30 million (by any calculation, one of the greatest weather related losses ever to occur in Minnesota)."
Risk of Acronyms - Severe Saturday, Then Cooler
By: Paul Douglas

When it comes to acronyms meteorology is even worse than the military: NOAA SPC has a svr risk today, with a good chance of an MCS system. NDFD data hints at low 90s before severe storms bubble up; NOAA's 4km NAM shows an afternoon CAPE of 5000 with a LI (lifted index) of -11. You get the idea. It's probably like this in every business, but get two nerdy meteorologists babbling about the weather and you may need subtitles.

Today should be the 4th day in a row of 90s; the last day of our July heat-wave. Dew points in the 70s will fuel today's thunderstorm outbreak, and once again I could see straight-line winds in excess of 60-70 mph. The best chance of running and screaming comes between 4-9 pm. Keep an eye on the sky and your smart phone, and always scope out a nearby shelter, just in case. Winds swing to the west Sunday with more sunshine and lower humidity - the nicer day of the weekend for the lake.

A beautiful Monday gives way to scattered showers and T-showers Tuesday into Friday as temperatures cool. With luck we may salvage warm sunshine next weekend, without any 90s.

Extended Forecast for Minneapolis

SATURDAY: PM severe storm risk. High 91. Low 68. Chance of precipitation 80%. Wind SE 10-20 mph.
SUNDAY: Partly sunny, breezy, less humid. High 85. Low 67. Chance of precipitation 10%. Wind NW 10-15 mph.
MONDAY: Blue sky, best day in sight. High 86. Low 70. Chance of precipitation 0%. Wind W 5-10 mph.
TUESDAY: Less sun, risk of a T-storm. High 85. Low 69. Chance of precipitation 30%. Wind SW 8-13 mph.
WEDNESDAY: AM sunshine, few PM storms pop up. High 83. Low 68. Chance of precipitation 30%. Wind SE 7-12 mph.
THURSDAY: Still unsettled, scattered T-showers. High 82. Low 66. Chance of precipitation 30%. Wind SE 10-15 mph.
FRIDAY: Showers and T-storms linger. High 79. Low 63. Chance of precipitation 50%. Wind NE 10-15 mph.
This Day in Weather History
July 23rd
1987: The greatest deluge ever recorded begins in the Twin Cities, with 10 inches of rain in six hours at MSP airport.
Average Temperatures & Precipitation for Minneapolis
July 23rd
Average High: 83F (Record: 105F set in 1934)
Average Low: 64F (Record: 47F set in 1876)
Average Precipitation: 0.12" (Record: 9.15" set in 1987)
Sunrise/Sunset Times for Minneapolis
July 23rd
Sunrise: 5:49 AM
Sunset: 8:49 PM
*Length Of Day: 15 hours, 00 minutes and 3 seconds
*Daylight Lost Since Yesterday: ~2 mins & 2 secs

*Next Sunrise That Is Before 6 AM: August 3rd (6:01 AM)
*Next Sunset That Is Before 8:30 PM: August 8th (8:29 PM)

Saturday Minnesota Weather Outlook

Forecast radar and satellite from the NAM 4k at 5 PM Saturday.

If you are heading out to the Aquatennial fireworks Saturday night, you will want to keep an eye on the weather. By the afternoon hours, a warm front will have lifted north across central Minnesota increasing moisture and instability. A cold front will be coming in behind it by the evening, sparking off strong to severe storms that will form into a line and quickly move east. A few of the storms, especially early on, will be capable of large hail, damaging winds and a tornado or two. Once the line forms, damaging winds will become the main threat.

A Slight Risk of severe weather (in yellow) is in place across much of the state Saturday due to this threat.

Heavy rain will also be a concern with these storms. There is the potential parts of central Minnesota could end up with 1-2"+ Saturday into Saturday Night.

Due to the favorable environment tomorrow for a heavy rain threat, combined with the recent heavy rain, a Flash Flood Watch has been issued for areas north of the metro, including Brainerd, Duluth, Hinckley and Foley. This is in effect from Saturday afternoon through Sunday morning.

Highs will be a touch cooler across the region Saturday, with highs only around 90 here in the Twin Cities.

Saturday National Forecast Outlook

Looking nationally, we'll also be watching the potential of scattered storms across parts of the eastern U.S. and in the Southwest.

Besides the severe threat across the North Central U.S. (including Minnesota), there is a Marginal Threat of severe weather across parts of New England. Isolated damaging winds and hail would be the main threat.

Heavy rain will also be possible in parts of the Southeast as we go through the weekend, with the potential of 1-2" of rain.

Record heat is possible in the Southwest Saturday, and 100s will be possible in the central Plains as far north as Kansas. Heat will also continue to spread into the Northeast, with highs into the mid/upper 90s as far north as the New York City area.
Thanks for checking in and have a great Saturday! Don't forget you can follow me on Twitter (@dkayserwx) or on Facebook (Meteorologist D.J. Kayser)!
-D.J. Kayser

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