June what?
(edits and strikeouts added Sat. 6 Oct)
What month is it? October!? Well, try telling that to the forecast models and the weather maps.
October, my ass! It’s June. At 4PM in Minneapolis, it was 87 degrees F with a dewpoint of 67 degrees F. We’re a mere 25 degrees above normal in both categories. Tonight will probably not get cooler than 75 in the city. If it doesn’t pour tomorrow, there is no justice.
A very interesting pattern will be unfolding over the next several days. A low pressure system is going to develop over eastern Colorado, but then it is going to cut itself off from from the tropospheric flow and get stuck somewhere in the Plains. Meanwhile, warm, humid air will surge out ahead of it while cold air pools up to its northwest. Little pulses of jet stream energy will surge over the stalled system, about every 18 hours or so, and all of this combines to make the forecast pretty daunting.
Temperatures throughout much of southern MN have the potential to be very warm, especially at night when cloudiness is likely to limit nocturnal radiational cooling. The record “high minimum” (i.e. the highest “low” temperature recorded) for October in Minneapolis is 72 degrees F. That record might be safe, but the high dewpoint record of 70 degrees F is not.
Lastly, we have the potential for severe weather. Lots of uncertainty yet, but major regional outbreaks are possible Friday, Saturday and Sunday.
One to watch
A system that should arrive Saturday looks very mean. (It does not look that mean anymore–Sat. Sept 29. Some severe weather is possible over western MN later this evening, but not the major outbreak that would likely have accompanied the scenario below if it had “verified.” The main threat today and tomorrow are from heavy rains. A very impressive system slated for Tuesday, however, has real severe weather potential, but I’ll let it go for now)
Below is a map of the jet stream winds at 7PM (CDT) Saturday, as forecast by the morning run of the Global Forecast System (GFS) model on Tuesday Sep. 25th. With the nose of a “jet streak” directed towards southern MN, this particular scenario leaves much of central and east-central MN in the “left-exit region,” which is a favorable location for severe weather. Given the strength of the jet streak (~100 knots), we could be talking about very severe weather. Several other things need to be in place, namely instability, moisture and lift. Plus, this model forecast is likely to change. Something to watch though.
Interesting NWS chart on number of days above 90 at MSP
Below is a variation of a stem-and-leaf chart, clipped and modified slightly from a recent news item by the Chanhassen, MN office of the NWS. In essence, this is a frequency distribution, or a histogram. The chart shows the number of 90-degree days per year, organized by count (from low to high). In this series the mode (the most common number) is 12, and the average is 13. I have bolded each year from 1999-2007 just to show a snapshot of recent summers. While all but two of these summers have been above normal, none have been out on the extreme end of the distribution, near the very bottom. Instead, they have been in the 55th-85th percentiles. What I find most interesting, is that if we found a similar measure for winter– perhaps # days above forty or lows below zero– I would imagine that most of those years would have been occupying the extremely warm side of the distribution. Thus, the simple chart below illustrates part of our current climate regime pretty well: winters have generally been extremely warm (not shown yet), but summers have generally been warm to very warm .
COUNT YEARS 0 1902 1915 1993 (LEAST) 1 1903 1904 1981 2 1967 3 1992 4 1907 1951 1990 1994 2004 5 1905 1918 1924 1997 6 1892 1962 1965 1986 2000 7 1998 8 1917 1919 1926 1984 1996 9 1906 1920 1927 1928 1942 1958 1985 10 1891 1899 1909 1944 1971 11 1912 1945 1956 1972 1977 1979 12 1908 1914 1946 1950 1954 1961 1969 1974 1989 1991 13 1896 1897 1898 1973 14 1929 1938 1968 2003 15 1893 1895 1922 1953 1960 16 1911 1913 1963 17 1952 1957 1982 18 1923 1980 1995 1999 2002 19 1900 1940 20 1925 1932 1975 1978 2001 2006 21 1910 1943 22 1916 1930 1941 23 1939 1966 24 1901 1987 2005 25 1935 26 1921 1970 1983 27 1947 1948 1964 2007 28 29 1959 30 1894 1931 31 1955 1976 32 1933 33 1949 34 1934 1937 35 36 1936
… 44 1988 (MOST)
Another Exciting One?
(Comment added Sept. 7: This was from a spam I [Kenny] sent to fellow geographers, Conor and a couple other folks. It did not “verify,” or in other words, most of what I warned did not happen. The main story was the very heavy rainfall, especially the flash-flooding in and around many Iron range communities.)
Friends, acquaintences, superiors, (and enemies?),
Tonight looks like another exciting one, meteorologically anyway, for much of the region.
Although the “dynamics” are not perfect, they will be improving through the evening, and essentially we could end up with two bouts of interesting weather. The first round should have two phases, and is organizing right now over eastern SD and western MN where thunderstorms are feeding off of the intense surface heating and high moisture content of the local airmass. Storms that develop before about 6 PM will have the potential to produce short-term excessive rainfall, large hail and strong winds. Intense (i.e. frequent) lightning will also be a major hazard with these storms. As these storms evolve and mature, especially as they interact with “mesoscale” (storm-scale) boundaries that result from cold air pouring out from the tops of other storms, the severe potential will increase, and at this point (between about 6 PM and 10 PM), tornadoes will become possible with any storms that are able to hog enough energy to become isolated from the other storms. At this time, it appears the main threat area for this first bout is north and west of Minneapolis, including much of central Minnesota and some of the far northwestern metro area.
The storms may fall apart somewhat after about 10 PM (then again, they may not), as the effects of the surface heating wear off. Shortly thereafter, however, as a second low-pressure system with better dynamics (upper-level winds and temperatures) ejects into the region from the southwest, existing storms may be rejuvinated, and/or new storms may develop. These storms will move a bit faster than the earlier storms, and will have the potential for significant wind damage. With this second possible bout of storms, the remainder of southern MN (including the Twin Cities area), and western WI would be the prime targets. The scenario at present looks as formidable as those that led to extensive wind damage throughout the region in August. Pinpointing where the damage will be is almost impossible, but I am pretty comfortable saying there will be *some* damage *somewhere* in the region.
Kenny
Star Tribune Article
Kenny humbly points you to this Star-Tribune article for which he was a source.
There was only one minor factual error, and perhaps one not quite perfect extrapolation, but the bottom line is correct: we occasionally have a “second” severe weather season in the fall, and recently we have had a historically-unusual number of late-season severe weather episodes and floods. Any single event is not unusual at all; it is part of our climatology. It’s the pattern of many significant events late in the season that is unusual. What this autumn will bring is unknown, but we have a chance for some interesting weather on Thursday and Friday.
Just Over a Year Ago
The summer of 2006 in Minnesota was typical in that it was pretty unusual. Huh? Like this year, we did not have our normal severe weather season from late May through mid-July. Instead, Minnesota’s most prolific storms were in August and September. On August 24th, everything came together for a full-blown severe weather outbreak. From morning through early afternoon, very large hail fell along the “cool” side of a warm front, across portions of the Twin Cities Metropolitan Area and points west and south. The hail was occasionally quite large, and caused millions of dollars in damage. In the late afternoon, an intense, tornadic thunderstorm developed just to the north of Mankato, dragging a large, damaging tornado along a 33-mile journey through mostly rural areas south and east of St. Peter. The tornado was rated an F3 (this is speculation, but it appears the tornado would have been an EF-3 in the new rating system), and it claimed one life. The tornado was very well forecast (honestly, storm chasers targeted the area that got hit hours before the parent storm formed), and therefore its entire lifecycle was documented by chasers and spotters. With a path width of up to 1/2 mile, we are all quite lucky this tornado was rural; it had relatively few “targets” to hit.
Other resources:
- Twister Sisters’ video of tornado
- Storm Prediction Center(maps, animations etc)
Thunderstorms have happened!
We recorded another show about the spate of severe weather we’ve recently experienced in the Twin Cities. Depending on where you live, between four and six significantly severe weather episodes have plagued the area during August alone! This has been a shot in the arm for weather junkies lamenting how boring the summer has been, but it’s not such good news if you’re a tree. The most recent storm on the morning of August 28th broke and uprooted hundreds of trees in Bloomington, MN alone.
Additionally, the drought conditions we’ve all been under for most of the summer have changed dramatically in the past few weeks. With parts of extreme southeastern MN and southwestern WI demolishing old rainfall old rainfall records, and with extreme flooding transforming the landscape–possibly permanently–it is difficult to imagine that drought was ever a concern (more pics here, and here). But, for much of central and northern Minnesota, the drought conditions have worsened. Most likely, these two extreme precipition regimes (drought and flood) will not coexist in such close proximity for long, so the question is, as a region, which way are we heading? Of course, you can stay up-to-date with the drought resources found here. In particular, this animation gives a good picture of how the situation has evolved over recent months.
This one was about 22 minutes. Featured music clip: Nick Walker
Finally Rain!
Something’s in the air. Three out of the last four days have brought heavy thunderstorms, including torrential rain and hail. Kenny is out tonight serving our nation as a “SkyWarn Spotter”. We’ll surely get together soon and discuss the recent atmospheric changes. Also, we’ll survey the damage in the Brainerd are from earlier tonight. 
New Website is Up!
I got the site up and working tonite. Now we can to try new things, like:
- Make the site capable of playing streaming MP3 files directly inside the browser.
- Create an image gallery for all of Kenny’s crazy storm chasing pictures and videos.
- Create categories to organize posts into appropriate topics.
Note: That’s all for now, we’ll contine to edit this site and add new content when available.
A short show about our show.
The purpose of this show was simply to explain our mission statement. It’s a short one.
- Make it fun to talk about the weather again
- Introduce Kenny and Conor
- Soundtrack - Ween - “Dancing in the Show”, Electrelane “Bells”
Recorded 7-16-2007, 11 minutes 18 seconds.