Dry Year thus Far...That is Until Summer With Warm June Flooding - Varability Forecast Continues

 

I headlined the Summer Outlook with; Will Variable Spring Weather Lead to a Variable Summer? This has been pretty much the case with the first half (yes officially, the meteorological summer is half way over mid July in spite of Labor Day weekend). Hot with a few notable cool spells, locally damaging storms, heavy flooding rains all intertwined with beautiful, pleasant summer weather. 

Summer analogues were quite mixed with rainfalls with dry, wet and one or two near normal rains. Which is why I went exactly what they had: below normal, above normal or normal...depending on location, location, location. Storm and frontal patterns have settled in the lower Great Lakes as air masses vie for dominance. Storm tracks and associated severe weather were a bit slow to materialize but made up for the delay as June unfolded.

After months of below normal precipitation, the dryness of the first half the year was alleviated to a large extent by the heavy rains and storms in June. As discussed; rains for the growing season were later than gardeners and farmers would have liked but their arrival was still very important for the growing season. Many areas got too much of a good thing with rainfalls of 4-6+" of rains by the end of the month and areas of flooding. Average or normal rains for June generally run 3-4", give or take a little.  And; as they say; a picture (or two) is worth a thousand words....

Yes, I know it's pretty tiny to read...for us needing coke-bottles>>>

Monthly Totals

Many areas hit with tropical-like rains 25th-27th

Sorry this map doesn't have cities & towns but counties are visible along with close approximations of Junes entire rainfall. It's not surprising to see why some of the newsworthy issues came up across the metro Detroit region; west along the I-94 corridor and northward to I-96 (Jefferies) / M14 region to west into and around Ann Arbor late in the month. Very heavy, tropical like rains deluged that region along a stationary front and low pressure area interacting with a tropical-like air mass. Rainfall totals with 6" to in excess of 8" were reported just in a 3 day period (see the DTX write-up here of the flooding and severe weather with a tornado touch down at Port Austin). This system was mainly responsible for the high rainfall totals of June across much of the region with some locations receiving in excess of ten inches. The very heavy rain areas only increased in size west over South-central and Southwest Lower Michigan.

Rainfall totals for June are smoothed in the first map below, with the second map showing much of the area receiving up to 200-300% of June's normal rainfall total on the Midwest Climate Center maps.

All three meteorological city rainfalls made it into the the top 20 wettest Junes. And; if you look a little longer - you'll see each location has had FIVE Junes thus far; making the wettest Junes list since the turn of the century. Still a little longer scan and you'll note a number of dry Junes have also placed since 2000, three at Detroit and Flint and two at Saginaw. This also reflects the variability found in the analogues but with a notable lean toward wetter. Typical summer rains tend to be feast or famine more so due to the nature of convective rains.
Rank	Detroit Area*				Flint Bishop**				Saginaw Area***
	Wettest		Driest		Wettest		Driest		Wettest		Driest
	Total	Year	Total	Year	Total	Year	Total	Year	Total	Year	Total	Year
1	8.31	1892	0.55	1895	6.57	2009	0.63	1988	10.76	2017	0.61	1988
2	7.04	1987	0.94	2011	6.52	1994	0.67	2016	6.92	1996	0.64	1952
3	6.97	1902	0.97	1988	6.40	2021	0.72	1995	5.82	1928	0.76	1912
4	6.97	1896	1.01	1959	5.87	1949	0.79	1933	5.65	2008	1.03	1927
5	6.58	1960	1.04	1984	5.58	1943	0.83	2012	5.15	1967	1.19	1956
6	6.42	1980	1.06	1952	5.48	2019	0.90	1952	5.09	1935	1.23	1925
7	6.32	1903	1.07	2002	5.46	2015	0.92	1984	5.05	2021	1.38	1918
8	6.05	1993	1.08	1904	5.40	1968	1.14	1959	4.93	1917	1.39	1964
9	6.01	2013	1.19	1933	5.37	1928	1.19	1932	4.92	1994	1.48	1959
10	5.90	1881	1.30	2016	5.36	1967	1.25	1998	4.83	1987	1.50	1991
11	5.75	1986	1.31	2012	5.31	1962	1.37	1925	4.75	1915	1.53	1990
12	5.49	1920	1.35	1932	5.23	1993	1.48	2002	4.71	1976	1.53	1923
13	5.46	1999	1.39	1934	5.13	1986	1.54	1985	4.67	1954	1.55	1997
14	5.42	2010	1.42	1913	4.90	1989	1.57	1997	4.62	1948	1.57	1929
15	5.32	2015	1.46	1922	4.82	1948	1.57	1934	4.56	2011	1.62	1941
16	5.27	2009	1.47	1910	4.70	1977	1.60	1987	4.49	2010	1.65	2006
17	5.24	1906	1.48	1911	4.68	1975	1.62	1923	4.41	1943	1.70	1934
18	5.16	2021	1.51	1876	4.56	1940	1.66	1978	4.37	1945	1.73	1966
19	5.15	1898	1.55	1995	4.51	2013	1.66	1922	4.22	1939	1.75	1963
20	4.99	1968	1.61	1956	4.44	1945	1.77	1927	4.21	1940	1.77	2016

      * Detroit Area precipitation records date back to November 1874.
** Flint Bishop precipitation records date back to January 1921.
*** Saginaw Area precipitation records date back to January 1912.

JUNE TEMPS

June's average temperatures were warm and sultry; warm enough to place in the top 20 warmest Junes at all three locations (Detroit, Flint and Saginaw. Even though warm; that's a bit misleading as the month was also blessed with intermittent, refreshing short cool breaks as the upper jet occasionally shifted to the north as upper lows over eastern Canada pushed cooler air masses into the Lakes Region. Here too; note the number of warmer Junes since 2000; Six at Detroit, four at Flint and five at Saginaw. Curiously; no colder Junes have made the lists since 2000 - except Flint with two. The Flint temperature observations are least affected by urban heat as compared to Detroit.

Top 20 Coldest/Warmest Junes 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	62.8	1985	74.6	1933	60.1	1969	75.0	1933	60.6	1982	73.8	1933
2	62.8	1903	74.1	2005	60.9	1958	74.9	1934	61.0	1926	73.5	1919
3	63.1	1915	74.0	1919	61.5	1980	72.1	1949	61.5	1915	72.3	1971
4	63.4	1928	73.3	1949	62.5	1985	71.7	1925	61.8	1958	72.3	1934
5	63.4	1926	73.2	1934	62.5	1972	71.5	1921	61.9	1917	71.7	2005
6	63.4	1916	72.8	2021	62.9	1982	71.4	2020	62.1	1980	71.1	2021
7	63.6	1927	72.8	1943	63.1	1977	71.3	1943	62.1	1916	70.5	1976
8	63.7	1980	72.7	1952	63.3	1960	71.2	2005	62.3	1945	70.5	1931
9	63.7	1889	72.4	1991	63.4	1928	70.3	1952	62.6	1928	70.4	1949
10	63.8	1878	72.3	2012	63.6	1945	70.3	1987	62.7	1977	70.3	1967
11	63.9	1958	72.2	1994	63.8	1927	70.3	1939	62.8	1985	70.2	1932
12	63.9	1902	71.6	1995	64.2	1992	70.1	2021	63.2	1947	70.0	1995
13	64.1	1917	71.6	1890	64.5	1947	69.8	1931	63.5	1969	69.9	2007
14	64.2	1982	71.5	2018	64.6	2003	69.8	1923	63.7	1972	69.9	1923
15	64.2	1972	71.5	1944	64.7	1961	69.7	2016	63.8	1927	69.9	1930
16	64.4	1881	71.4	2010	64.9	1986	69.7	1991	64.2	1978	69.9	1921
17	64.6	1935	71.4	1921	64.9	2009	69.6	1954	64.2	1940	69.8	2012
18	64.6	1897	71.3	2007	64.9	1974	69.6	1932	64.2	1924	69.8	1987
19	64.7	1969	71.3	1954	65.1	1978	69.5	1971	64.3	1918	69.7	2014
20	64.8	1907	71.3	1987	65.1	1948	69.5	1944	64.4	1986	69.7	199

What about the rest of the summer? There were a few trends noted in upper air patterns and the analogues in the Outlook possibly reflecting temperature and rainfalls for the rest of the summers.

While I determined the analogues averaged too cool:

From Outlook

Mainly because of the warming the latter quarter of the 20th century into the early 21st century; analogues from earliest periods have been generally discounted or less weighted than the later period analogues. Basically; many of the earlier analogues have been considered too cool for our present warmer period the past several years. However; all analogues are considered for patterns and timing.

Remainder of the summer:

Keeping in the above normal temperature mode for the remainder of the summer along with now; normal to above rainfall. Recent and longer term model patterns do suggest warmer and wetter conditions. However; analogues do suggest a drier month or period anyway is due the second half of the summer. Nearly all analogue summer years had a notable drier period and more likely in the second half of the summer. We'll see.

 Models:

 

As you can see the CFSv2 displays a "W" type of La Nina(s) from last winter to the up coming autumn into winter 2021-22

 TEMPS

 

PCPN

It's interesting to note the model catches a non-determinant rainfall forecast for August over Southern Michigan, which is wrapped around with above normal rainfall chances. This loosely reflects the analogue drier periods and is more reflective the natural rhythm of frontal action working northward across the Lakes late summer.

The Outlook for the autumn reflects warmer with lesser precipitation conditions reflective in La Nina falls.

Taking a trip around the world and interrogating climate models shows a bit lean toward a stronger La Nina for the 2021-22 season. Engaging in that last year, the CFSv2 reflected that view for last year's La Nina.

 

Milder autumn temperatures are rule across the pond, also.

A drier trend also creeps into the Midwest and continues in parts of the Plains..

Newsworthy weather and other articles will pop-up from time to time on FB and here, on my Weather Historian page. Enjoy the rest of the summer and autumn!

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