Tornadoes, Snowstorms and Heat Waves - Oh May!

While March is generally considered one of the most volatile months in Southeast Lower Michigan weather-wise, May doesn't pull any punches either! You would think that by May; spring's extreme weather in these parts would settle down some - don't bet on it. Scanning over a century's worth of weather records show some interesting and quite variable weather conditions during the upcoming month.


One of the strongest and earliest documented tornadoes in Southeast Lower Michigan occurred in May, 1896! While details are sketchy, evidently a massive tornado plowed across Oakland and Lapeer Counties during the early evening hours on May 25th sometime between 7 PM to 9 PM. The tornado leveled numerous homes in the towns of Ortonville, Oakwood and Thomas ( both no longer exist). In fact, parts of these homes were found 12 miles away! At least 47 people were killed, including nine people from one house alone, along with approximately 100 injured as a result of this vicious storm which has been estimated as an EF-5 (wind speeds greater than 200 mph). Later that evening (likely closer to 9 PM), another tornado was seen in Sanilac County which possibly was from the same parent of super-cell thunderstorms. It's also interesting to note that May of 1896 turned out to be the fourth warmest May (see May Top 20 records chart at the end of this write-up) in recorded history at Detroit, perhaps the unseasonably warm weather helped fuel the severe weather. I was interviewed by the Oakland Press years back in 2009 about this terrible tornado. Also, included in the article are pictures of the now defunct town Oakwood before and after.

Some of the strongest tornadoes to hit Southeast Lower Michigan occurred in the early to mid 1950's. The most noteworthy was the monster Flint/Beecher tornado that occurred in 1953 also an EF-5, but that storm hit in the month of June (8th). (An in‑depth article I wrote on the tornado can be found here). Unfortunately, Genesee County was hit again just three years later on May 12th, 1956 with another devastating tornado (EF4 on the enhanced fujita scale with a wind of 166‑200 mph). After the Flint/Beecher storm, this is the second strongest tornado to hit Genesse County. Like its predecessor, this storm also formed in the Flint vicinity (3 miles east of Flint) but then tracked southeast to 3 miles northwest of Atlas rather than east. This tornado killed 3 people and injured 116 while taking out more than 100 homes and five commercial buildings along its path. The average width of the storm was about 300 feet and it is the last killer tornado to hit Genesse County.

Just less than a month before the massive Flint/Beecher tornado in June 8th, on May 21st,1953 the first of two EF4's (166-200 mph) tornadoes ever to hit St. Clair county tore a mean path through the south side of Port Huron. By all accounts, the south side of Port Huron was devastated by this twister. There were two deaths and 68 injuries along with an estimated 90 homes destroyed and another 300 damaged as the tornado ripped through the region. Also, along with the loss of homes, an additional 83 buildings were destroyed and another 124 buildings damaged. As a severe thunderstorm moved northeast across St. Clair county, the tornado was spawned just southwest of Port Huron over the town of Smith's Creek. The tornado then took aim on the south side of Port Huron, reaching nearly a mile wide across at its worst as it tore through the area on its way into Canada.

The second EF4 tornado to hit St. Clair county also occurred in May...May 8th, 1964 The tornado actually developed over Macomb County, 3 miles north of Mt. Clemens, then plowed east northeast across New Baltimore to just north of Algonac, in extreme southern  St. Clair County, before crossing the St. Clair River into Canada. This tornado killed 11 people and injured more than 200 as it destroyed 132 homes and damaged another 240 homes and farms. But this tornado wasn't the most damaging in St. Clair County. That distinction belongs to an EF3 (136‑165 mph) tornado that hit St. Clair and Macomb Counties also in May...May 2nd, 1983. The tornado was again spawned over Macomb County, this time over the extreme southeast portion of the county near Eastpointe. The storm then blew across Lake St. Clair and into Harsens Island and damaged or demolished 25 to 30 homes, an aircraft hangar and a large building. The estimated cost of the damage was over $5 million.

Snow-OH !


While a few snow flurries or snow showers are all not that rare in Southeast Lower Michigan in the month of May, the following two snowstorms were and both I wrote in-depth about; here!
One storm occurred May 21st‑22nd, 1883, while the other, the more documented of the two, hit the area May 9th, 1923. The snowstorm on May 9th, 1923 was probably the most severe and extensive over Southeast Lower Michigan of the two ( I wrote in‑depth article on this storm very early in my Weather Historian career. 1996 titled "Snowstorm of May 9th, 1923").  Records at Detroit show a six‑inch snowfall by the evening of the 9th, while further north and west of the city it was even worse! Six to nine inches fell across the Ann Arbor area north into Howell and east, across Pontiac and Port Huron. Even more incredible, snow depths flirting with a foot were observed from Lansing and Flint area, north into the Saginaw Valley and Thumb Region. Widespread damage occurred when such a heavy wet snow fell on top of the newly sprouted spring vegetation. Afternoon and evening temperatures hovered in the lower to mid 30s, while a bitter cold (particularly for May) northwest wind blew at 15 to 25 mph.

The May 21st‑22nd, 1883 snowstorm by the date alone sounds almost unbelievable! Very little was written in the archaic Detroit weather records about the storm at the time. In fact, the snowstorm was not confirmed until much later (1904), since officially continuous snowfall records did not start until 1885. The following is from the official observation form...
                                                         May 21, 1883
            Rain began at 900am. Snow from 250pm to 910pm. Hail 934am to
           1005am and 110pm. Strong wind reaching 36 mph from the North.
           Temp from 32.5  to 46.0. Baro rising.
                                                         May 22, 1883
           Hail ended during the night. Snow began during the night. Rain and
           snow  ended 1005am. Northerly wind reaching 28 miles. Temp from 
           32.5 to 41.0  Snowfall estimated by Inspector Conger to have been
           5.0 in ‑ on 21st&22nd    (This entry made April 28, 1904 ‑ CDC.J)

The snowfall was split between the two days and recorded as 2.3 inches on the 21st and 2.7 inches on the 22nd. While hail was a likelihood, especially in the afternoon on the 21st as the colder air moved in, I suspect the hail recorded overnight into the 22nd could have well been graupel or sleet. One may also wonder with such cold air advected into the region at the surface and aloft in late May,  if thundersnow (sleet/hail) didn't also occur somewhere over Southeast Lower Michigan, especially with accumulating snow. The snowfall recorded on the 21st & 22nd in 1883 is by far the latest measurable snowfall recorded in Metro Detroit. The next closest, heaviest measurable snowfall date‑wise is 1.5 inches, which fell on May 13th, 1912 and then, our other big storm with the total of six inches on May 9th, 1923. The latest snow was officially observed in Detroit was the last day of May...May 31st, 1910 when a trace fell. By the way, it's interesting to note that not one of the pre-mentioned Mays with measurable snowfall placed in the top 10 coldest Mays in Detroit.

May Daily Snowfall Records
Date Snowfall (Inches) Year Date
1 0.3 1909 1
2 0.1 1909 2
3 0.1 2005 3
4 0.2 1907 4
5 0.0 2015 5
6 0.0 2015 6
7 0.0 2015 7
8 0.0 2015 8
9 6.0 1923 9
10 0.5 1902 10
11 0.0 2015 11
12 0.0 2015 12
13 1.5 1912 13
14 0.0 2015 14
15 0.0 2015 15
16 0.0 2015 16
17 0.0 2015 17
18 0.0 2015 18
19 0.0 2015 19
20 0.0 2015 20
21 2.3 1883 21
22 2.7 1883 22
23 0.0 2015 23
24 0.0 2015 24
25 0.0 2015 25
26 0.0 2015 26
27 0.0 2015 27
28 0.0 2015 28
29 0.0 2015 29
30 0.0 2015 30
31 T 1910 31


Now, from one extreme to another, lets look at Heat Waves. While there have been hot days in May with records into the 90s, there are only two years that had extended periods of hot weather in May and those are 1962 and 1977. The hottest and more consecutive of the two was in 1962 when from May 14th‑May 18th, the daily high temperature climbed to ninety or above. This hot spell created five new consecutive record high temperatures which still stand to this day. In 1977, there were also five new record highs established but they were not consecutive, nor all in the 90s up until 2007 & 2012 when two were superseded (see: Tables, below). Very recently (in climate terms) May of 2012 was a very warm month and had its share of records also.

May - Detroit Records 1874 - Present
May Normals
Maximum Minimum Average Daily
Date Max Min Avg Record
Highest Lowest Greatest Date
1 65 45 55.0 86/1942 40/1909 70/1942 26/1978 78/1942 35/1909 1.46/1875 1
2 66 45 55.0 85/2012 39/1940 64/1942 29/1978 73/1942 34/1875 1.66/1892 2
3 66 45 56.0 89/2012 40/1929 64/1955 28/1978 76/1955 38/1957 1.31/1997 3
4 66 46 56.0 89/1949 45/1954 66/1955 28/1966 77/1955 39/1954 1.05/1990 4
5 67 46 56.0 90/1895 42/1917 70/1949 29/1891 80/1949 38/1917 0.85/1991 5
6 67 46 56.0 90/1949 46/1935 66/1941 31/1974 74/2000 40/1974 1.75/1976 6
7 67 46 57.0 86/2000 40/1947 68/1964 27/1974 77/2000 36/1947 0.97/1948 7
8 67 47 57.0 87/2015 38/1947 68/2000 30/1976 77/2000 34/1947 0.85/1974 8
9 68 47 57.0 90/1896 39/1923 68/1965 29/1983 79/1896 35/1923 2.12/1875 9
10 68 47 58.0 90/1936 42/1902 67/1896 25/1966 78/1896 38/1966 2.33/1948 10
11 68 48 58.0 87/1993 43/1960 67/1881 30/1907 76/1896 39/1907 1.91/1914 11
12 69 48 58.0 90/1881 44/1966 65/1881 32/1934 78/1881 39/1895 1.48/2002 12
13 69 48 59.0 89/1977 45/1888 66/1956 30/2013 77/1991 41/1910 1.48/1991 13
14 69 49 59.0 91/1962 40/1895 66/1962 34/1984 79/1962 39/1895 1.39/1916 14
15 70 49 59.0 92/1962 48/1945 71/1962 33/1973 82/1962 42/1895 1.46/1923 15
16 70 49 60.0 92/1962 47/1945 70/1962 32/1984 81/1962 44/1957 1.09/1945 16
17 70 50 60.0 93/1962 48/1916 67/1962 31/1973 80/1962 43/1973 1.22/1980 17
18 71 50 60.0 93/1962 48/1915 70/1962 32/1973 82/1962 43/2002 1.50/2000 18
19 71 50 61.0 91/1934 40/1894 69/1996 32/2002 80/1996 37/1894 1.68/1949 19
20 71 51 61.0 91/1977 48/2002 68/1934 33/1981 79/1934 42/1895 1.56/1959 20
21 71 51 61.0 92/1977 46/1917 71/2013 32/1883 80/1934 39/1883 1.69/2004 21
22 72 51 62.0 90/1994 41/1883 67/1941 32/1883 78/1941 36/1883 1.14/1949 22
23 72 52 62.0 89/1964 46/1917 71/1964 34/1935 80/1964 40/1917 1.69/2004 23
24 72 52 62.0 87/2007 44/1925 67/1991 33/1925 77/1933 39/1925 1.26/1950 24
25 73 52 62.0 90/2012 47/1979 70/2012 35/1992 80/2012 45/1979 1.67/2011 25
26 73 53 63.0 92/1944 47/1961 70/1991 36/1983 79/1914 43/1961 2.56/1968 26
27 73 53 63.0 91/1941 51/1906 71/1941 35/1915 81/1941 46/1915 1.68/2014 27
28 74 53 64.0 95/2012 52/1930 72/1941 35/1907 82/1941 46/1894 2.02/1935 28
29 74 54 64.0 92/2006 48/1889 70/2006 32/1966 81/2006 42/1889 1.65/1876 29
30 74 54 64.0 93/1942 44/1889 73/1929 36/1966 81/1929 40/1889 2.27/1889 30
31 75 55 65.0 95/1895 46/1910 71/1919 34/1910 83/1895 26/1898 1.98/1946 31

Normal High: 69.9

Normal HDD: Month: 208

Normal Monthly Precip: 3.38
Normal Low : 49.4 Normal HDD Season: 6092 Normal Yearly Precip: 12.54
Normal Mean: 59.7 Normal CDD: Month: 42 Ave Snow this Month : -1.0

Normal CDD Season: 48 Ave Snow for the Season: 42.7

Precip: Greatest Monthly Total: 8.46/2004

Snow: Greatest Monthly Total: 6.0/1923
Precip: Least Monthly Total: 0.43/1920 Snow: Least Monthly Total: 0.0/na
                            1962                                                                     1977
DATE.............RECORD HIGH..........................DATE..............RECORD HIGH
5/14                         91                                        5/13                          89   
5/15                         92                                        5/20                          91
5/16                         92                                        5/21                          92
5/17                         93                                        5/24                          87/equaled & superseded 2007/
5/18                         93                                        5/25                          89 /superseded by 90 2012/
Both Mays placed in the top ten hottest Mays in Detroit with 1962 placing 5th and 1977 placing 8th with recent editions of 2015, 2012, 1998 & 1991. Ironically; May of 1991 placed at the top of the list for the warmest May but ironically, not one record high temperature was set that month.

Top 20 Coldest/Warmest Mays in Southeast Lower Michigan
Rank Detroit Area* Flint Bishop** Saginaw Area***
Coldest Warmest Coldest Warmest Coldest Warmest
Temp Year Temp Year Temp Year Temp Year Temp Year Temp Year
1 51.1 1907 66.5 1991 48.7 1997 65.0 1982 49.8 1924 64.6 1977
2 51.3 1917 65.5 1998 50.0 1966 65.0 1936 49.9 1945 64.0 1998
3 51.8 1967 65.3 2012 50.6 1967 64.7 1934 50.0 1917 63.4 1975
4 51.9 1966 65.3 1896 50.6 1945 64.4 1922 50.2 1997 63.2 1991
5 52.0 1997 65.2 1962 51.5 1984 64.2 1991 51.3 1947 62.8 1936
6 52.1 1924 64.7 1911 51.9 1947 62.9 2015 51.6 1967 62.7 1934
7 52.5 1945 64.5 2015 52.5 1961 62.9 2012 51.6 1915 62.5 1982
8 52.6 1935 64.4 1977 52.6 1973 62.9 1998 51.8 1925 62.5 1922
9 52.7 1882 64.3 1881 52.7 1954 62.7 1987 51.9 2002 62.2 2012
10 53.1 1915 64.2 1982 52.9 1968 62.6 1977 51.9 1983 61.6 2015
11 53.8 1947 63.7 1964 52.9 1924 61.9 2013 51.9 1954 61.5 2013
12 53.9 1910 63.7 1880 53.1 2002 61.9 1939 52.1 1966 61.5 1962
13 54.2 1883 63.6 2013 53.4 2005 61.8 1975 52.5 1946 61.3 2010
14 54.3 1888 63.3 1987 53.5 1983 61.6 1965 52.7 1935 61.1 1964
15 54.4 1983 63.3 1944 53.8 1974 61.5 1962 52.8 1948 61.1 1959
16 54.5 1984 63.1 1965 53.8 1948 61.4 1944 53.0 1974 61.0 1985
17 54.5 2002 63.0 1887 54.0 1957 61.1 1933 53.1 1956 60.7 1965
18 54.5 1890 62.8 1975 54.1 1963 61.1 1921 53.4 1957 60.5 1988
19 54.7 1954 62.8 1936 54.1 1935 60.9 1959 53.4 1923 60.4 1987
20 54.7 1925 62.8 1922 54.1 1925 60.9 1941 53.6 2003 60.4 1941
* Detroit Area temperature records date back to January 1874.

** Flint Bishop temperature records date back to January 1921.

*** Saginaw Area temperature records date back to January 1912.

Try to enjoy May's weather whatever it brings!   

Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian


Late Season Storm To Mix It Up Over Southeast Lower Michigan

An intensifying low pressure system moving through the Upper Ohio Valley & Southern Great Lakes will push a variety of stormy spring and winter weather across Southeast Lower Michigan. The worst of this storm as far as precipitation continues to focus to be west and north of the immediate Detroit area including the southeast corner of Lower Michigan. Heaviest rains of an inch to two with isolated heavier amounts will fall in an arc-shape out over regions toward Lansing - Flint - Saginaw and Thumb Region. Regions further southeast, can expect generally 3/4" to 1 1/2" and isolated heavier amounts.

In addition to the heavy rains, strong northeast winds gusting into the 30s and peaking to 40 - 50 mph (stronger near the Lakes) and some thunderstorms can be expected to move across the region overnight. Local lowland and possible local river and stream flooding will also be a problem with the heaviest rains. Strong northeast to north winds and heavy snow may cause power interruptions - and nearshore erosion along the Lake shores, mainly Lake Huron.

Colder air will filter into Southeast Lower Michigan from the northwest to southeast during the early morning hours through the day on Thursday; changing the rain over to snow and snow showers slowly from northwest to southeast.

-Update snow amounts a bit less than earlier forecast-
Largest snow accumulations are likely to occur away from the Southeast corner of Lower Michigan. Snow areas include the areas west of Detroit into the Ann Arbor region, across the northwest and north suburbs of Detroit extending out toward Lansing - Flint - Saginaw and Thumb Region. Snowfalls of 3" to isolated 5" in areas furthest west and north of metro Detroit in the aforemention area above, with decreasing anounts of near 3" to an inch or less in areas further to the southeast.

Friday for the Tiger game, actually looks similar to last year's opener with cold conditions with temps rising just into the lower to mid 40s and brisk north winds.


April 6th, 2017 -April 7th 2017

2am Thu

 2pm Thu

8pm Thu

2am Fri

8am Fri

Snowfall projections by the GFS  by 8am Fri 4/6/17


Ironically the anniversary of Detroit's biggest snowstorm also falls on tomorrow's date, April 6th 2017. Way, way back on April 6th, 1886 - or 131 years ago - the largest snowfall ever recorded in Detroit occurred with 24.5"- or just a dusting over two feet!!  Here's the story of that storm along with our infamous December 1st, 1974 storm, which brought the second heaviest snowfall to Detroit 19.3" - and their similarities.

By: William R Deedler, Southeast Michigan Weather Historian

Initially, I had intended to write about Detroit's biggest snowstorm ever recorded (24.5") but while researching the storm (which occurred way back on April 6th, 1886), I was struck by the uncanny similarities between that storm and Detroit's second biggest snowstorm (19.3") which occurred nearly a century later on December 1st, 1974. Besides the obvious similar snowfall amount between the two systems, other significant parallels could also be drawn. In addition, while I was obviously not around to observe the first huge storm, I did have the opportunity to witness the second first-hand, in my earliest days with the National Weather Service. Unfortunately, weather maps for the1886 storm are unavailable, unlike the 1974 storm (below). With the aid of surface observations and weather journals however, at least an estimate of the surface and upper air data can be made. Perusing through the carefully scrolled weather journals of the late 1800's, one can't help but be amazed and "taken back" by the simplistic, yet stylish way of which they were written. In addition to hourly weather observations and climatic statistics, each day contains usually a short synopsis of the weather experienced for that day. It is the weather logs from late on April 5th - April 7th, 1886 that really commands ones attention and awe.
APRIL 1886 -
By early April 1886, some residents of Southeast Lower Michigan had most likely started on spring outdoor activities. High temperatures frequently pushed well into the 50s from mid March on; the last hint of snow fell nearly two weeks before on the 23rd. No doubt the growing season's new green vegetation was well underway.
The weather days proceeding the massive and incredible snowstorm hinted little of what was yet to come; however, there were some subtle signs of trouble brewing. The first was a fresh, brisk northeast wind that blew continuously for nearly three days prior to 6th (generally, an easterly wind along with a falling barometer in this region, foretells of foul weather approaching the area). On the 4th into the 5th, observations including temperatures, wind flow and pressure changes indicated an unseasonably cold high pressure system pushing slowly into Southern Canada and the Northern Great Lakes. This persistent and strengthening northeast wind along with an extended period of steady, then slowly falling barometric pressure, during the three-day period (3rd, 4th and 5th), indicates this high was a fairly strong, resilient and a blocking type of high pressure. A second and more foreboding sign of what was to come was indeed a rapidly falling barometric pressure later on the 5th, which foretold of the major storm approaching Southeast Lower Michigan. The surface observations late on the 5th indicated a low pressure and storm center approaching the Southern Great Lakes from the south or southwest (most likely from Illinois, Indiana or Ohio) as the cold high to the north slowly retreated.
The afternoon high on the 5th reached only 38 degrees (about 15 degrees below normal) and then held nearly steady into the evening. Increasing high cirrostratus clouds mingled with the sunset but then, quickly lowered to altostratus and nimbostratus as midnight approached. Light snow began to fly just after midnight and remained light until becoming heavy during the predawn hours. Note the following taken from the actual Detroit Weather Log dated April 6th, 1886:

"Snow began at 12:30 AM and fell light until about 4:30 AM when it began to fall heavy and a tremendous fall of snow continued all day, ending at 9:00 PM. The fall at 7:00 AM was 4.6" and at 3:00 PM was 17.1" and at 11:00 PM, 2.4" making the total of 24.1 inches melted from the snow gauge. The rain gauge was soon snowed full and was practically useless. Total fall of the snow on the level was 24.5 inches. The snow was badly drifted by the heavy gale. The drifts in some places were 12 feet high and the snow in the street was from 10" to 40" inches deep. A heavy north gale set in at 1:45 AM and raged in fury all day reaching 40 miles north at 2:15 PM and continued all the remainder of the day. Its force with the snow was appalling. It blew the snow in fine particles against the face, cutting like a knife."
The synopsis continues with a description of numerous street cars that were abandoned, strewn about and laying in all sorts of positions. As one might expect with the snow falling in April, the snow contained a high water content (2.43") and, therefore, it was very heavy and packed down well. Obviously, wading through the snow to get around on foot was extremely difficult - so much so that it became necessary to use crowbars and ice picks just to clean a path on the street. Maneuvering through, or just moving the snow, was such a monumental chore that even several ton railroad cars were "held prisoner in their houses". On the train tracks, freight cars were immobilized and abandoned across all of Southeast Lower Michigan. Temperatures held in the upper 20s to around 30 through the entire snowfall, with over two feet of snow reported on the ground. The strong northeast to north gale sculptured towering drifts of snow up to 12 feet high across the landscape .The howling wind averaged over 30 mph during the 24 hour period. The lowest barometric pressure reading noted was 29.60 inches at 11:00 AM on the 6th. This reading isn't too terribly deep or severe (the lowest pressure ever observed in Detroit was 28.34 inches during the late January blizzard of 1978), but the pressure was taken only five times daily (7:00 AM, 11:00 AM, 3:00 PM, 7:00 PM and 11:00 PM), so it likely fell lower As the center of the low pressure drifted further north into the Great Lakes on the 7th, milder air from the south was drawn into Southeast Lower Michigan. The sky cleared as the wind shifted to the south and the temperature rose to 40 degrees, in spite of the very heavy snow cover. In the days following the storm, temperatures managed to push up well into the 50s and even reached the mid 70s by mid month, after all, this was April, right?
This storm stands as Detroit's biggest and severest snowstorm and is well summarized by the following quote in the journal and actually would still stand to this day. . .

"The storm was unprecedented in fierceness, snowfall and blockades in the history of the service and the oldest inhabitants can recall nothing to equal it".
It would be nearly a century later before a very similar storm, a sort of "meteorological clone" would arrive and again leave the region snowbound with the second highest snowfall (19.3" as compared to 24.5") ever recorded in metropolitan Detroit in a single storm. While there were several similarities between the two storms, one obvious difference was their timing in the snow season. Also, it is interesting to note here, that neither storm occurred during what is officially called "winter." While the 1974 storm occurred in late fall at the forefront of the 1974-75 winter season, the April 1886 storm showed up on the doorstep of spring.

Besides the similar heavy snowfall between the storms, there is the likeness of the surface observations taken before and during each storm. As its predecessor, the 1974 storm was proceeded by a few days of persistent northeast winds along with an initially rising barometric pressure, then after, an extended period of steady pressure readings before giving way, slowly at first, to falling pressure. Also, like the 1886 storm, temperatures crept up into the mid to upper 30s on both the 29th and 30th (though these highs were not anywhere near as below normal as in the April 1886 storm). On the 30th, the northeast wind averaged around 19 mph with peak gusts close to 30 mph. The persistent strong northeast wind with just a slow climb in daytime temperature was a result of a large stationary polar ridge axis of high pressure that extended in a horseshoe shape (an Omega High) from the Great Plains, north into the Dakotas, then east across Lake Superior into Quebec, Canada and finally south along the East Coast. The high's strength and position also recalls that of the1886's high pressure mentioned previously.
The development and track of this super snowstorm was complicated and quite a hassle for forecasters that Thanksgiving weekend. The primitive forecast models (when compared to the more sophisticated and better resolution of today's models) had quite a time in predicting the track of the storm and its intensity. Even up to the day of the storm, the forecast models continued to weaken the center of the storm as it moved into Kentucky and Ohio, while intensifying a new storm along the East coast. On Saturday, November 30th, a strong closed-off 500 MB Low advanced into the Mid-Mississippi Valley, while at the same time, at the surface, an inverted trough of low pressure extended from a low over the northern Gulf of Mexico, north northwest to a second low over Missouri. The consensus of the forecast models was to bring the 500 MB and surface low generally east, into the Ohio Valley and weakening both. In the meantime, the Gulf Low was forecast to track north northeast up the East Coast and intensify; thus, becoming the main low and storm center of the entire system. This was the accepted forecast scenario with the data available at the time and could hardly be argued otherwise. Actually, this predicted path and subsequent weakening of the Ohio Valley low as the East Coast storm intensifies or "bombs-out" is what generally happens. The models failed in forecasting the weakening trend of the Ohio Valley system. The 500 MB Low and the surface low not only did not weaken, they actually intensified and became vertically stacked in the atmosphere. Generally, when this happens the system tends to hold on to its intensity longer and slow down in movement, both of which proved detrimental to the computer forecast.
Light snow moved into extreme Southeast Lower Michigan during the predawn hours between 5:00 AM and 7:00 AM. Even at the 5:00 AM forecast issuance, it looked as if just one to three inches of snow would blanket extreme Southeast Lower Michigan for this event. However, by sunrise, already up to three inches of snow covered the region and the snow was not getting any lighter. A stiff northeaster' also accompanied this storm, though not as severely as the 1886 storm, averaging 20 to 30 mph with gusts above 30 mph. By sunrise, an area of snow had settled over extreme Southeast Lower Michigan. On radar during the forenoon hours, bands of heavier snow appeared over Northern Ohio and Lake Erie, trekking west-northwest toward Michigan. By now, the forecasters knew the forecast was in trouble and updated the forecast to read "six or more" inches of snow.

The 500 MB Low and associated energy to support the surface system drifted east over Kentucky, while the surface low that was over Missouri drifted east right along with it. A huge conveyor belt of moisture had set up in the atmosphere extending from the Gulf of Mexico and the Western Atlantic, east into the Ohio Valley and Southern Great Lakes. Not only had the storm tapped the usual Gulf moisture; now Atlantic moisture started to be drawn into the mix. After analyzing surface data from the 1886 storm, it is strongly suspected that this too was the case at that time. Huge moisture plumes from both the Atlantic and Gulf of Mexico fed the1974 storm and likely, the1886 storm, with nearly duplicate surface observations before and during the event.

Bands of snow (much of it moderate to heavy) continued to be produced across the Eastern Great Lake States on the "conveyor-belt" through the afternoon, with the heaviest snow falling across extreme Southern Ontario, extreme Southeast Lower Michigan and extreme Northwest Ohio. By mid afternoon, already between six and ten inches of snow was on ground across much of extreme Southeast Lower Michigan, with generally eight to ten inches in the metro Detroit area. Visibilities were frequently near zero and moderate northeast winds blew the heavy, wet snow into at least three to five foot drifts. Another notable item observed during the storm was frequency of large snow flakes. Generally in the majority of snowstorms there may be a period or two of heavy snow with large flakes and a quick accumulation of snow. During this storm however, there were several periods, or waves, of heavy snow with continuous large flakes and very low visibilities, migrating in from the east over the region.

The surface low drifted north northeast from Kentucky into West Virginia by Sunday evening on the 1st and gradually matured and occluded. It still remained however, the dominant low (which was not forecasted by the forecast models), while the second low on east coast moved north at the triple point (at the point where the occluded, warm and cold front of the system met) and never really developed. As darkness fell, generally up to a foot and a half of snow smothered the metro Detroit area, with six to twelve inches elsewhere in extreme Southeast Lower Michigan. During the evening the snowfall became lighter and by midnight, 18.4" was officially observed at Detroit Metro Airport. Another nine tenths of an inch fell early on the 2nd, for a grand total of 19.3" (19.2" of it falling in 24 hours) with Flint reporting a snowstorm total of 8.1". As the low drifted northward, milder air filtered into the region and the snow became mixed with, and then changed to drizzle.

Coincidentally, the next day (Monday, December 2nd, 1974), the temperature also warmed to 40 degrees in the afternoon, but the wind remained more northerly rather that shifting to the south (as on April 7th, 1886). This was due to the fact that the center of the low tracked further east of Southeast Lower Michigan into Pennsylvania, rather than into the suspected Great Lakes area in 1886.

Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian


Deep Low Pressure System and Attending Strong Upper Air Dynamics Pushing Through The Region Friday Night

   . . .SEVERE WEATHER UPDATE - 2/24/17 AT 12 NOON FRIDAY . . .
    NORTHERN KY...  
    Severe thunderstorms are forecast to affect areas from Lower
    Michigan southward to Tennessee, mainly this afternoon through
    tonight.  The primary threat appears to be damaging wind, but some
    hail and a few tornadoes will also be possible. 
 ...Southern Lower MI/Northern IN...
    Only minor changes have been made to the ongoing forecast.  Water
    vapor loops show a large upper trough over the Central Plains, while
    a deep surface low tracks northeastward across northern IL.  The
    initial severe concern will be ahead of the surface low and into the
    vicinity of the warm front lifting northward into MI.  Relatively
    strong heating and low level moisture advection will result in
    MLCAPE values around 1000 J/kg along and south of the boundary.  12z
    model solutions are consistent in developing scattered thunderstorms
    along this corridor this afternoon and early evening.  Forecast
    soundings suggest a favorable vertical shear profile for discrete
    supercells capable of large hail and damaging winds.  This portion
    of the outlook area holds the greatest concern for supercell
    tornadoes later today.

Previous 2/22/17 Write-Up and Update....

A strong spring-like system will be surging through the Great Lakes and Upper Ohio Valley Friday into Saturday. The unseasonably warm, spring-like temperatures that have affected Southeast Lower Michigan for the past several days will be rudely pushed east of the later Friday night and Saturday.

Ahead of the front; this clash of the spring-like and winter air masses will also bring the potential for strong damaging winds as showers and thunderstorms barrel through the area Friday afternoon into early Saturday morning. This storm system, more typical of a classic late March or April storm system, will also bring the risk of a rather unusual event of severe weather for February.

The set-up Friday night based on Latest NAM, 00Z - 022317

The deep low will occlude and move through Lower Michigan Friday afternoon into the first half of Friday night. Heavy to very heavy showers and scattered thunderstorms can be expected to charge ahead of the cold front and along the warm front. Very strong gusty winds will accompany the activity with gusts in excess of 50 mph are likely in the worst of the storms.

All severe weather parameters (and some not shown) paint the best instability, bulk shear, lapse rates and unusual (for February), surface based CAPE over Southern and Southeast Lower Michigan. The nose of an 80knot Bulk Shear coming into the Southern Great Lakes, certainly draws attention to the potential of realized damaging winds any heavy shower or storm could bring down. At the very least, the idea of a "thunder-less" line of heavy showers with potential severe winds would also be a threat with this system.

A potential for short-fused severe weather event is in the wings from Friday evening into the first half of the night till about 2am EST Saturday morning at this early juncture. Strong low pressure system and attending warm and cold fronts will be barrelling across Southern Lower Michigan at that time.

                                                From the Storm Prediction Center

...Southern Great Lakes and Ohio Valley...
Low-level moisture is forecast to slowly increase on strong
southerly flow with boundary-layer dewpoints forecast to range 52-58 degrees F. Although cloud cover will retard strong surface heating, cooling mid-level temperatures to around -19 degrees C will contribute to weak buoyancy (ranging from 250-1000 J/kg MUCAPE) within the northward expanding warm sector during the day. As strong forcing for ascent (DCVA) approaches and overspreads the western parts of the area, a band of thunderstorms will likely develop and intensify. Strong effective shear around 50 kt will act to organize updrafts and strengthening 700-mb flow to the 55-60 kt range will contribute to cold pool's organization and upscale growth. Downward momentum transport via damaging winds are the predominant severe risk. However, some forecast soundings show relatively moist low levels with strong 0-1 km shear in excess of 25-30 kt. A tornado risk may develop with the maturing squall line and/or pre-frontal supercell(s) that eventually merges with the line. A gradual weakening in buoyancy by the early to mid evening into the overnight will likely lead to a lessening in the damaging-wind risk as storms rapidly move east and northeastward after dark.

Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian


Roller-coaster Pattern of the Winter About to Get Revved Up Again

It's been a slow winter for potential storm discussions but as we turn the calendar from February into March, our various models have been in overdrive trying to peg potential storms from the last weekend of February into the first two weeks of March.

All indications are the "ole' sling-shot pattern" (a strong jet stream that digs south from western Canada into the southern California and/or Rockies & Plains before loading and shooting northeast somewhere in the Midwest/Lakes) will be a major player in the roller-coaster pattern prevalent so much this winter.

 More to follow....

Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian


Digging Further into January's Weather Records Bring's More Rareness and Oddities - January 2017 Update

There's no doubt about it; besides the more typical climate statistics for the month of January ("warmest, wettest, etc etc), January 2017 had more to offer than the usual headlines.

True, January 2017 was the 12th warmest January on record at Detroit and Flint, while being the 15th warmest at Saginaw. Abundant rainfall of 3.13" made January the 6th wettest in Flint and while both Detroit and Saginaw had above normal rains, the top 20 list was not breached. Snowfalls were near to slightly below normal in most regions.

Elaborating on the oddities mentioned in the my article on January recently (below); January 2017 was also a stand-out month for any January (and other months) with cloud cover, lack of sunshine, dense fog and thunderstorms. Digging back over my records for Detroit, show that January 2017 was indeed lacking in sunshine due to the cloud cover. The sunshine normals or historical data is available up through June 1995. The sunshine switch was then removed from DTW and placed in at DTX. However, due to frequent errors in readings after the move, it was later terminated and dismantled. Past sunshine minutes, percentages and normals were last printed in the 1995 DTW Annual LCD. Again, this was after the NWS moved out of  DTW and DTW became a Contract Station.

January's cloud cover, sunrise to sunset /sr - ss/ is on the monthly F6 below and totaled 8.8 or rounded off  to 9, out of a possible 10. January 2017 had 26 cloudy or mostly cloudy days, 3 partly cloudy days and just 2 clear or mostly clear days. This compares to the averages or normals for January sky conditions/as follows: the 125 year ave /1871-1995/ amount of cloudy days in January sunrise - sunset /sr-ss/ averages to 20,  there are 7 partly cloudy days and 4 for clear. The 105 year average /1891-1995/ of possible sunshine in Detroit for January stands at about 36% while the 110 year average /1886-1995/ cloud cover for January is around 7.5 tenths.

Therefore yes January was a gloomy month - but a record? 


                                          STATION:   DETROIT MI
                                          MONTH:     JANUARY
                                          YEAR:      2017
                                          LATITUDE:   42 13 N
                                          LONGITUDE:  83 20 W

1   2   3   4   5  6A  6B    7    8   9   10  11  12  13   14  15   16   17  18
                                     12Z  AVG MX 2MIN

 1  41  23  32   6  33   0 0.00  0.0    0  5.9 14 210   M    M   2 18     17 190
 2  43  27  35   9  30   0 0.08  0.0    0  6.4 12  90   M    M   9 18     17  90
 3  45  38  42  16  23   0 0.36  0.0    0  8.1 18 290   M    M  10 12     24 280
 4  38  19  29   3  36   0 0.01  0.2    0 19.3 24 280   M    M  10        46 280
 5  20  12  16 -10  49   0 0.03  0.7    T 12.2 21 250   M    M   9 8      24 270
 6  17   8  13 -13  52   0    T    T    T  9.1 16 240   M    M   8 18     29 270
 7  17   5  11 -15  54   0 0.02  0.7    T 11.2 21 310   M    M   7 89     28 310
 8  18   8  13 -13  52   0 0.00  0.0    1 10.0 17 290   M    M   5        23 280
 9  31  16  24  -2  41   0    T    T    1 12.4 21 210   M    M  10        25 220
10  49  27  38  12  27   0 0.53  3.0    3 20.2 41 250   M    M  10 1246   53 260
11  57  29  43  17  22   0 0.13  0.0    0 13.9 33 250   M    M   9 138    42 240
12  58  29  44  19  21   0 0.40  0.0    0 11.4 29 230   M    M  10 13     42 220
13  29  20  25   0  40   0 0.00  0.0    0  8.1 17 280   M    M  10        23 280
14  33  23  28   3  37   0 0.00  0.0    0  4.4 10  80   M    M   8        13  90
15  34  18  26   1  39   0 0.00  0.0    0  3.9  9 200   M    M   3 18     12 220
16  36  19  28   3  37   0 0.15  0.0    0  3.3 13 100   M    M   9 168    16 100
17  48  33  41  16  24   0 0.42  0.0    0  8.6 18 250   M    M   9 1236   23 240
18  43  35  39  14  26   0    T  0.0    0 11.0 18 220   M    M  10 1      24 210
19  38  33  36  11  29   0 0.00  0.0    0  7.8 17 240   M    M  10 18     21 240
20  42  33  38  13  27   0 0.16  0.0    0  5.7 13  60   M    M  10 12     16  60
21  59  40  50  25  15   0    T  0.0    0  3.2 10 170   M    M   7 128    13 180
22  49  40  45  20  20   0 0.00  0.0    0  3.9  9  80   M    M  10 12     11  60
23  46  41  44  19  21   0 0.11  0.0    0  7.3 13  60   M    M  10 12     16  50
24  42  39  41  16  24   0 0.04  0.0    0  7.2 17 310   M    M  10 12     22 300
25  48  36  42  17  23   0 0.01  0.0    0 10.1 29 230   M    M  10 18     35 220
26  42  35  39  14  26   0    T    T    0 16.1 26 230   M    M  10 4      32 250
27  35  28  32   7  33   0 0.01  0.1    0 14.7 24 260   M    M  10 46     32 240
28  31  28  30   4  35   0 0.02  0.5    T 13.8 20 230   M    M  10 189    25 240
29  30  25  28   2  37   0 0.05  2.0    1  7.2 15 300   M    M  10 18     19 310
30  27  18  23  -3  42   0 0.06  1.4    2  7.0 14 190   M    M   9 1      19 240
31  36  26  31   5  34   0 0.24  3.2    6  9.1 17 270   M    M  10 18     32 280
SM 1182  811      1009   0  2.83    11.8 292.5          M      274
AV 38.1 26.2                               9.4 FASTST   M    M   9    MAX(MPH)
                                 MISC ---->  # 41 250               # 53  260



                                          STATION:  DETROIT MI
                                          MONTH:    JANUARY
                                          YEAR:     2017
                                          LATITUDE:   42 13 N
                                          LONGITUDE:  83 20 W


HIGHEST:    59 ON 21    GRTST 24HR  0.57 ON 16-17      TO 1/4 MILE OR LESS
LOWEST:      5 ON  7                               3 = THUNDER
                        SNOW, ICE PELLETS, HAIL    4 = ICE PELLETS
                        TOTAL MONTH:  11.8 INCHES  5 = HAIL
                        GRTST 24HR   3.2 ON   M    6 = FREEZING RAIN OR DRIZZLE
                        GRTST DEPTH:   6 ON 31     7 = DUSTSTORM OR SANDSTORM:
                                                       VSBY 1/2 MILE OR LESS
                                                   8 = SMOKE OR HAZE
                                                   X = TORNADO
MAX 32 OR BELOW:   9    0.01 INCH OR MORE:  19
MAX 90 OR ABOVE:   0    0.10 INCH OR MORE:   9
MIN 32 OR BELOW:  20    0.50 INCH OR MORE:   1
MIN  0 OR BELOW:   0    1.00 INCH OR MORE:   0

[HDD (BASE 65) ]
TOTAL THIS MO.  1009    CLEAR  (SCALE 0-3)   2
DPTR FM NORMAL  -214    PTCLDY (SCALE 4-7)   3
TOTAL FM JUL 1  2987    CLOUDY (SCALE 8-10) 26




      MONTH  &   YEAR          NUMBER
 *    JANUARY      1960            9.3
1-**NOVEMBER 1985              9.3
   **JANUARY     1960              9.3
   **DECEMBER 1929               9.3
2-**NOVEMBER 1992               9.2
9-   JANUARY      2017             8.8
      (JANUARY      1932            8.6)

      MONTH & YEAR          NUMBER
*     JANUARY    1932            14%
1-**DECEMBER 1929              7%
2-**NOVEMBER 1985            13%
?   JANUARY     2017            N/A

November 1985, January 1960 and  December 1929 all tie for the cloudiest month ever in Detroit.  January 2017 doesn't even come close to the cloudiest month nor cloudiest January with 8.8 cloud cover /9th place/.

Looking at the previous sunrise-sunset cloud cover records and least sunshine records above, we can basically be assured that January 2017 would not have placed for the least sunniest month (December 1929 has that honor). How about the least sunniest January?  

January 2017 is a just a contender for the least sunniest January by the following reasoning...

Obviously, it's difficult to say how much sunshine Detroit had in January 2017 since it wasn't recorded locally and doesn't always correlate or is the inverse of cloud cover. Case in point from above: Lowest sunshine on record for January is 14% in 1932 but this occurred with less cloud cover at 8.6 as opposed to the 16% of sunshine in January 1960 with a higher amount of cloud cover at a record 9.3! If one was only to go by a direct correlation by cloud cover and subsequent lack of sunshine alone; then there is a higher chance, January 2017 contained less sunshine than January 1932.  However it isn't always that simple...

Here's where being an older-timer weather observer has its merits, so try to follow along...

It really has to do more to do with the type of clouds and their thickness observed during the day/month and resulting opaqueness.  In the "old days" of the NWS, observations of cloud cover was recorded in both total coverage and opaqueness of the total; say for example 10/10 of cirrostratus (usually a high but partially thin cloud cover) and its opaqueness, might be 10/5. Therefore the observation read something like; 200-OVC (or in the teletype days when I started, it was 200-O with a cross in the middle - sent out and read on teletype but not displayed on a weather map). The symbol (-) was read as thin, when the opaqueness of a cloud cover was half or less. Basically meaning; one could discern the blue sky above (or stars/moon at night). With the advent of ASOS, the thinner parts of all types of cloud cover was lost in the observation. This is where the human element of a weather observation was better to discern the actually cloud cover and its thickness. Clouds above 12,000ft are not officially observed on ASOS therefore some mid clouds and all high clouds are lost - and certainly their opaqueness! This was/is crap to most pre-ASOS days weather observers and many other weather aficionados. Wtih ASOS, sometimes the higher clouds are still augmented  (edited)  into the ASOS where human observers are co-located with ASOS.

Ok, back to the subject at hand...

The absolute dreariest month for sunshine happened after the stock market crash of 1929 when December 1929 had only 7% of the possible (well below anything other month).  I guess mom nature got in on the mood around metro Detroit and the country. Keep in mind, the month of December 1929 has the least amount of possible sunshine during any given December and month. Therefore; December 1929 with just 7% of the possible was indeed, the gloomiest month. Another interesting tidbit for December 1929; however was its Christmas was one of the whitest in Detroit's history with 11 1/2" of snow on the ground.
And talk about down right depressing:

It should be noted that November and December 1972 have the record for the gloomiest period /60 days/ in what I could find in both cloud cover and subsequent sunshine (or lack there-of).

    MONTH  &   YEAR          NUMBER  
NOVEMBER      1972                 9.1
DECEMBER      1972                 9.0

    MONTH  &   YEAR         SUNSHINE (%)    

 NOVEMBER      1972               13%
 DECEMBER      1972               13%

So, you see this past January wasn't so bad. There were other times during the 1970s in the winter I recall cloudy, dreary months around here and stats back me up; November 1977 /9.1/ December 1974 /8.7/ and actually it didn't end there in the monthly stats. The whole year of 1972 had 7.1 cloud cover for the cloudiest year on record at Detroit with 1984 a close second at 7.0. More 1970's show up here for cloudier years too, 1970 and 1973 at 6.9, 1974 at 6.8. Actually it sort of follows; being that some of the years in the 1970s, tended to be a bit more stormy in both winter and severe weather seasons...there'd also be more cloud cover. And, that leads me to thunderstorms in January...


YEAR          NUMBER
2017                    3
1909                    3
1907                    2

Thunderstorm days in January while not unheard-of are fairly rare with an average since 1871 of just about .2 (or well less than one day in January). Therefore you can reason, that January thunderstorms days are few and far between.


 * JUNE          1973                9
**JANUARY  1907                 8
   JANUARY  2017                 8 /TIED WITH 1907 & THUS SUPERSEDES/

There were 8 days total during the month of January (20-24th, 5 dense fog days in a row) which was also very rare. Occurrences of dense fog in January is 2 days on average. January 2017 totaled just one day less the the all time record for dense fog days which belongs to June of 1973. However; January tied for first place for the month of January with 8 days which was also observed in January 1907. Just for an extreme comparison; there were only 6 days in all of 2015 that dense fog was recorded at DTW. The annual average for the year is about 17 days for dense fog.

Previous Preliminary January write-up through January 22nd... 

"Strange January to Get back on Track Later This Week"

It's been an odd and very variable January this year. The first several days started out mild, then a cold blast commencing on the 5th reminded Southeast Lower Michigan inhabitants what month it really was with temperatures well below normal - but that didn't last long did it? We turned the corner by the 9th and again, it was off to the races to warmth with high temperatures basically in the 50s for three days before a slight 4-day cool down took hold through the 16th. Since then; readings have continually averaged above or well above normal through the 21st /yesterday/. In fact; Detroit's high on the 21st of 59 reached the peak reading thus far for the month, making that the third upper 50-degree temperature this month! Not to be a record however as that honor belongs to Jan 21st of 1906 with 65! If we're going to speak of records, Flint's high temperature of 54 on the 21st came within one degree of its 55 degree record in 1954.

In the midst of January's wild roller-coaster ride of frequent up and down temperature swings; came just as many resulting weather phenomena - some typically seen and some not during January. Snow and cold of course, ranks on the side of normalcy in January; whereas balmy spring-like temperatures interspersed through the month, thunderstorms and many dense fog days do not. Oh sure they happen in January; and if at any time, usually during our cyclical January thaw which comes regularly enough to nudge up temperature records in past data during mid to late month for several days. However, there's certainly been more than a weeks duration of thawing weather this January with several notable upward temperature swings during the month. So much so, that even with the bitter cold experienced earlier in the month, readings are averaging 4 - 5 degrees above normal and enough so; that we are beginning to enter the top 20 warmest January's list at all three stations in the bottom (upper teens to 20). Three thunderstorm days have ranked up this month thus far at Detroit, an unusual amount being its the dead of the winter. Dense fog days have just eclipsed (6/5-as of the 22nd) the number of snow days thus far in January with nearly a week total in days where visibilities at Detroit Metro Arpt dropped down to a 1/4 mile or less. Last night (21st-22nd) being the foggiest I've seen it in quite awhile around metro Detroit. Dense fog advisories have been carried/existed since Saturday evening /21st/ (now Sun eve night, 22nd).

The snow machine sputtered the first ten days of the month but then died completely after the tenth. What had been a relatively snowy winter thus far into early January went bye-bye since, with 4.6" recorded the first ten days at Detroit. Flint did a bit better with 5.7" and Saginaw topped it with 7.4" To be fair; all three climate stations still are above normal for the snow season of 2016-17 by about 2-4" - but don't look for much of any addition this week as temperatures hold basically above normal with mainly rain expected until about Friday. The better chances for any addition of light snow will be across the northern portions of Southeast Michigan but then, rain is expected to mix with the snow, which should cut down any appreciable accumulations. Actually more rain than snow days have been observed this month with all of Southeast Lower Michigan having a wet January thus far. Detroit is nearly an inch above normal (a decent departure for January); Flint is nearly an inch and a half above while Saginaw rests at about three quarters above average".

Note; Due to the lack of records for some weather items in Detroit's LCD since 1995, some records were estimated using very long term records which were then, updated.

Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian