7/14/18

Projected Dry Spell Materialized Across Southeast Lower Michigan

In my Summer Outlook there was a fairly strong signal that our wet year thus far through the spring would dry-out somewhat and sometime during the summer. In the Summer Outlook:


RAINFALL:

"All researched data suggests a normal to below normal rainfall summer. While there were a few moderately wet summers, they were at a minimum. The wettest summer by far was the cool and wet summer of 2000 (No repeat, please)! Most summers indicated at least one dry spell, typical for summers in these parts with the majority of analogue years showing one notable (an inch or more) rain deficit month. This would be a drop from current trends thus far this wet year".

Thus far this July, many areas have seen a 1/4" or less of rain in the last two weeks. The only minor exception has been in the Saginaw Valley to the tip of the Thumb that was brushed with more measurable rain Friday. Detroit Metro Airport has reported only a trace thus far for the month through the 13th.

Perhaps no where is the lack of rain more evident (except for your backyard) than the percentage of normal rain maps.

RAINFALL:

Map 1

Last 30 days

Map 2
Last Two Weeks
Map 1
In the past month, most of Southeast Lower Michigan has accumulated 50% - 75% of its normal rain. That isn't great with most of the rain falling back in mid June with little appreciative rain since then.

Map 2
The lack of rain can be really appreciated looking at Map 2. Most areas have seen less that less 1/4" of rain in July thus far. However; remember that map time-period could be extended and actually encompass the past three weeks from June 23rd - July 13th.

Adding insult to injury; it's been hot this past month with the majority of the time high temperatures averaged 2 - 4 degrees above normal.


TEMPS:

Map 3



While chances of rain are up the next few days (Sat-Mon night) I'm not too excited yet, as our below average rainfall trend may still hold sway.

Seriously though; I'm really hoping we break the dry spell during the second half of July and it makes up for the dry first part. Looking further out this week; if we don't get any appreciable rain the next few days, then rain chances will dwindle back down to zilch the remainder of the work week. The good news though is the cooler and drier air scheduled for Tuesday through most of the week.

Keep the hoses handy.


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


 

6/17/18

Hot - Hot: Give Us All You Got!

THE "GRAND DADDY" OF SOUTHEAST MICHIGAN HEAT WAVES 

                                             July 8th - July 14th, 1936

 (originally written in the late 1990s with update 2013)

Written by: William R. Deedler, Weather Historian 
 
Though heat waves or hot spells generally occur nearly every summer, no heat wave compares in intensity nor in duration than the heat wave that occurred across Southeast Lower Michigan in the summer of 1936. For many of us, it was when our grandparents were in their young or middle-age adult years. Little, if any, exaggeration would accompany their tales of the oppressive heat experienced sixty years ago, back in July 1936.

The last week of June into the first week of July 1936 was quite variable with afternoon highs ranging from around 70 to near 90. Evidently, weather patterns were quite progressive. After a day or two of heat build up, a cold front would push through the area and sweep the heat to the south and east on a regular basis. A change in the weather pattern was heralded by a strong but dry warm front that pushed across the area midday on July 6th. Very warm air rushed north into Southeast Lower Michigan, causing the mercury to rise up to near 90 on the 7th, but this was merely a hint of the heat to come.

On the afternoon of the 8th, the temperature soared to just shy of 105 (104.4) degrees and thus, the unprecedented heat was on. For the next seven consecutive days, the mercury would "bubble" above the 100 degree mark (see Table 1). The oppressive heat was compounded by humidity levels generally ranging in the 30s and 40s during the afternoon hours. While those levels are relatively low any other time, when combined with temperatures 100+, the heat index or, how hot it really felt, ranged roughly from 110 to 130 degrees. Little, if any relief was found during the evening hours into midnight with temperatures ranging from the mid and upper 90s at the start (6 to 7 pm) to hovering still in the mid 80s at midnight. For a few hours before dawn, overnight low temperatures "cooled" into the mid 70s. Desert-like conditions were exaggerated by the non-existence of rain. The thirst of the parched land was left un-quenched as not one drop of rain was officially recorded at the Detroit downtown office through the period.

Since this was 1936, the residents of Southeast Lower Michigan did not have the luxury of air conditioned homes, businesses or shopping malls to take refuge from the heat. Most people had to make do with the old standbys such as fans, blocks of ice from the Ice Man (the Ice Man cometh') or maybe by just taking a swim. While other heat waves in Southeast Lower Michigan have lasted longer, none had been longer accompanied by the fierce heat of this one. I was unable to find any documentation of heat related deaths (I'm not sure it was even done at this time), but with this intense of a heat wave, I'm sure there were cases.

The break in this torturous heat wave came without fanfare (storms). Not even a shower was noted in the log. Looking at the observations on the 14th...the wind shifted from the southwest to the northwest and then to the northeast. A lot of the characteristics of a "backdoor" cold front pushing south- southwest out of southern Canada. Occasionally these fronts will come through dry with an abrupt wind shift and falling temperatures. The temperatures fell from 104 at 200 pm...to 85 at 400 pm to a relatively chilly 69 by midnight. The heat wave started with a 104 degree reading on the 8th and ended with the same on the 14th. The first drop of rain was long in coming and not observed until a measly .08 fell on the 23rd.
 
Table-1 - Summary of the daily highs, lows and resultant means
-------   for July 8th - 14th, 1936 in Detroit, Michigan.
         
           Date          High      Low       Mean
                       
         July  8th       104 *      72        88
                  
         July  9th       102        75        89
                                    
         July 10th       102        77        90 **
                                    
         July 11th       101        77        89 
                                    
         July 12th       100        76        88 
                                    
         July 13th       102        73        88
                                    
         July 14th       104        69        87
                                                        
              *  Second highest all time temp 
              ** Second highest all time mean

Another, very notable heat wave that baked the area for a longer period of time but was not quite as hot, occurred in the late summer of 1953 from August 26th - September 3rd. An eleven day string 90 degrees or better, cooked the area. What's worse, nine of those days were 95 degrees or higher, with two of those hitting the century mark. Those two 100 degree days occurred near the end of the heat wave on September 2nd and 3rd, and with the exception of one other day, were the latest 100 degree days ever reported in Detroit (the latest 100 was also back in the "dust bowl" 1930s, on September 15th, 1939). Still another heat wave, in the Summer of '64, was one day longer (12) than the one in 1953 and has the "honor" of the longest heat wave on record when looking at just consecutive days of 90 degrees or greater. This heat wave extended from July 17th - 28th, 1964. There were no 100 degree days during this period, with the highest temperature being "only" 95.

On a more recent note and better in the memory of Southeast Lower Michiganders, is the hot summer of 1988, when a record amount of 90 degree or better days, 39 to be exact, produced one hot, sultry summer. The previous record was 36 days which again, occurred in "dust bowl 30s" (1934) when also, the hottest temperature of all time, (105 July 24th, 1934), occurred in Detroit. In addition to the record amount of 90 degree days in 1988, we topped the 100 mark 5 times, with the highest at 104 on June 25th. We missed the all time high by just a degree, but for those who remember, a hot, desert-like wind blew across the area that day as dew points dropped into the lower 60s, and humidities fell into the 20s.

That memorable summer of '88 became the seventh hottest summer (Jun-Aug) ever recorded in Detroit with a average of 74.2 (see updated listings below). The fourth hottest summer goes to 1955, with an average of 74.4 degrees. During that hot summer, the month of July set the record for days of 90 degrees or greater in a month with 17. This was the primary reason why July 1955 became second hottest month ever in Detroit, with a average temperature of 79.1. Last July (2012) superseded that temperatures with 79.3 for Detroit's hottest July. We now come to our hottest summers, at least in the last 142 years (1870). The "gold" medals goes to 1995 and again,  just last year in 2012! That's right, just last year during the 3 month summer period (Jun-Aug), Detroit averaged 74.5 degrees helped tremendously by the hottest July. Strangely enough though, back in July 1995 that July didn't even place in the top 10 hottest months. The hot month in the Summer of '95 was August, with an average temperature of 77.1, making it the hottest August on record. June 1995 placed in at the eleventh hottest.

Here is the updated top 7 Hottest/Coldest Summers on record at Detroit, Flint and Saginaw. Several of our recent summers have entered the record books for heat and changed previous rankings, especially at Detroit.

Top 20 Coldest/Warmest Summers 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 66.5 1915 74.8 2012 65.4 1992 74.2 1933 64.8 1915 73.0 1933
2 67.0 1992 74.8 2005 66.1 2009 74.0 1934 65.1 1992 73.0 1931
3 67.3 1927 74.5 1995 66.2 1958 72.7 1936 65.5 1982 72.5 1955
4 67.5 1875 74.5 1955 66.3 1960 72.6 1939 65.8 1945 72.3 1995
5 67.6 1903 74.4 2011 66.5 1969 72.6 1931 65.9 1950 72.1 1930
6 67.8 1985 74.4 2010 66.6 2004 72.6 1921 65.9 1924 72.1 1921
7 67.9 1912 74.2 1988 66.7 1985 72.3 2010 66.1 1985 72.0 2012



The Deadly Summer Heat

Written by: Jeff Boyne - National Weather Service La Crosse Wi
 
In a normal summer, about a 175 Americans die as a result of the taxing effect that excessive heat and humidity can have on the body. In a disastrous heat wave of 1980 more than 1,250 people died in St. Louis, Missouri. Just last summer, Chicago experienced its worst weather-related disaster with 465 heat related deaths recorded during the period from July 11-27.

How Heat and Humidity Affects the Body:

The human body gets rid of excessive heat (above 98.6 F) by increasing the rate of the blood circulation. This causes the blood vessels to expand to accommodate the increased flow. The tiny blood capillaries in the upper layers of the skin are also put into operation. By doing this, the blood is able to circulate closer to the skin's surface and the excess heat in the body is able to be dispensed into the cooler atmosphere surrounding the body.

At the same time, water diffuses through the skin from the sweat glands in the form of perspiration. Sweating, by itself, does nothing to cool the body. Evaporation of the perspiration must take place in order for the process of sweating to be of any use. When perspiration evaporates, it takes some of the excess heat away from the body; thus, the body is cooled.

If high humidity accompanies the hot temperatures, the body will have a very hard time cooling itself down, because the perspiration on the skin will not evaporate off of the skin. As a result, the body will continue to try to cool itself down by sweating. This will not only cause the body to lose water, but it will also lose salt. If the body cannot cool itself down or if it loses too much salt, one of the following three heat disorders will result in the table-2 below.

Table-2 3 Types of Heat Disorders
HEAT DISORDER SYMPTOMS FIRST AID
Heat Cramps Painful spasms usually in the muscles of the legs and abdomen. Heavy sweating. Get the person to a cooler place. If the victim has no other injuries and can tolerate water, give one- glassful every 15 minutes for an hour.
Heat Exhaustion Heavy sweating, weakness, skin cold, pale and clammy. Pulse thready. Normal temperature possible. Fainting and vomiting. Get the person out of the heat and and into a cooler place. Have them lie down on their back and elevate their feet with something. Either remove or loosen the victims clothing Cool them by fanning and applying cold packs (putting a cloth between the pack and the victim's skin) or wet towels or sheets. Care for shock. Give the victim one-half glassful of water to drink every 15 minutes, if they can tolerate it. These first aid steps should bring improvement within a half hour.
Heat Stroke High body temperature (106 F or higher). Hot, dry skin. Rapid and strong pulse. Possible unconsciousness Heat stroke is a life-threatening situation. Call 911. Get the person out of the heat and into a cooler place. Cool the victim fast. Immerse them in a cool bath, or wrap the wet sheets around their body and fan it. Care for shock by laying the victim on their back and elevate the feet with something Wait for medical help to arrive. Also do not give anything by the mouth.

The most susceptible people to the above heat disorders are the very young, very old, chronically ill, overweight, those who work in hot places, and athletes. Studies indicate that, other things being equal, the severity of heat disorders tends to increase with age. Heat cramps in a 17-year old may be heat exhaustion in someone 40, and heat stroke in a person over 60.

The Heat Index:

This index is used to alert the public how hot it really feels when the Relative Humidity is added to the actual air temperature. These values were devised for shady, light wind conditions.

Table-3 Heat Index (or Apparent Temperature) Chart


Heat Index



Relative Humidity (%)


40 45 50 55 60 65 70 75 80 85 90 95 100
A 110 136











i 108 130 137










r 106 124 130 137










104 119 124 131 137








T 102 114 119 124 130 137







e 100 109 114 118 124 129 136






m 98 105 109 113 117 123 128 134





p 96 101 104 108 112 116 121 126 132




e 94 97 100 103 106 110 114 119 124 129 136


r 92 94 96 99 101 105 108 112 116 121 126 131

a 90 91 93 95 97 100 103 103 109 113 117 122 127 132
t 88 88 89 91 93 95 98 100 103 106 110 113 117 121
u 86 85 87 88 89 91 93 95 97 100 102 105 108 112
r 84 83 84 85 86 88 89 90 92 94 96 98 100 103
e 82 81 82 83 84 84 85 86 88 89 90 91 93 95
(°F) 80 80 80 81 81 82 82 83 84 84 85 86 86 87

With Prolonged Exposure and/or Physical Activity
Extreme Danger Danger Extreme Caution Caution
Heat stroke or sunstroke highly likely Sunstroke, muscle cramps, and/or heat exhaustion likely Sunstroke, muscle cramps, and/or heat exhaustion possible Fatigue possible


*Editor's note: 7/11/13
I wrote the above article in the late 1990s. At the time, 1964 looked to be the longest streak BUT an 89 degree high occurred at DET City Arpt during the hot stretch (checked DET to DTW), In 1964, DET WAS the official site...so it can't be used...DTW Metro Arpt became the official site in April 1966. Funny what a problem a digit can cause (and it WAS 90 at DTW so it was hot anyway)!

The 1953 hot and miserable streak IS the longest heatwave with the Grand Daddy of all Heatwaves in Detroit in 1936 with the hottest and most miserable streak of days above 100 degrees. The all time hottest day at Detroit though was 105 back on July 24th, 1934. Back in the hot summer of 1988 we almost tied that with a 104 on June 25th 1988!

Before I retired, I went over all of Detroit's records and caught a few other mistakes... some back to the 1800s. Detroit's observation site moved several times in its history.

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

6/12/18

A Change In The Calendar; A Change In The Weather - But For How Long?

Before you go saying June's been a rather cool month; you might want to look at the actual temperatures and departures. Believe it or not, June 2018 has averaged a degree /+1.1/ above normal for nearly the first third of the month (through the 9th). Why it feels so cool is coming off the second warmest May on record; especially the latter third or so. The comparison of high temperatures and departures is quite dramatic...


    MAY 2018<              >JUNE 2018


May 23-31 was exceptionally warm and more like a mini-heatwave in the middle of the summer; whereas June 1-9, temperatures dropped considerable to basically, normal levels for early June. No where than the daily high temperatures and daily departures (both highlighted in yellow) is this displayed better. However; short term indications are for June's "cool spell"  to heat up going into the middle of the month.

Back to the data; the daily rainfall (WTR) might have caught your eye;after a early and middle wet May, things are beginning to dry out some, depending on your location. Lighter rains fell in some parts of metro Detroit while heavier rains fell in other areas. Heaviest rain this past weekend was across Shiawassee and Genesee Counties where reports of of up to two inches were reported.

So what about the whole month of June?

While the June analogues were mixed; there was a lean toward an average to a slightly below June temperature month. Five June's averaged below normal (more than 0.3 of a degree); four averaged normal (within 0.3 of a degree and three above (better than 0.3 of a degree). I cut the temperature categories down smaller to a third of a degree; just for a closer representation of actual numerical departure. This has nothing to do in the analogue performance since I use a whole degree for the season as being above, below or normal. The same goes for the departure in rainfall categories; using better than a third of an inch for above or below, or within a third for normal (see Month Legend).

Rainfall leans toward below the average in June with six below normal, three normal and three above. During the summer with convective rains this tends to be quite variable but the basic trend did show drier than average in area coverage.

I thought the analogues were a bit too cool this season, one reason was their comparison to today's norms which have risen over the decades (discussed in Summer Outlook); partly reflecting the metro heat island. Therefore; I'm looking for a temperatures to average normal to above for the entire month of June with below normal rains dominating the countryside.  






JUNDEPART
T"+/- N"
70.71
68.71
69.51
66.62
67.83
70.62
62.84
69.42
69.53
69.34
67.85
72.33
68.8
69.4
-0.6




JUNDEPART
P"+/- N"
2.631
1.822
1.483
3.301
3.134
3.262
1.625
4.901
3.403
3.952
5.273
1.316
3.00
3.52
-0.52
Month Legend:
TempsDegrees
Below" >-0.3
Normal"-0.3 - +0.3
Above" >+0.3
RainInches
Below" >-0.33
Normal"-0.33 - +0.33
Above" >+0.33


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
























6/2/18

Summer of 2018 Outlook for Southeast Lower Michigan - Including a Look at Spring, Summer and Lake Levels

First a wrap-up on May 2018 and Spring 2018


The combination of a cold early-mid spring across Southeast Lower Michigan (with temperatures averaging in the mid to upper 30s -normal's are lower to mid 40s) resulted in a very slow green-up due to the colder air and soil temperatures. In stark contrast, because of the exceptionally warm and wet May and presiding wet soil (see first half of 2018 rainfall below);  gave Southeast Lower Michigan one of the fastest green-ups this Weather Historian has ever witnessed. In a matter of a week or two what was nearly bare became lush with greenery, especially by mid May.

The spring analogues had projected May's temperatures to have the best chance to be above normal including two of the top 10 warmest Mays to boot: 1911 for 7th warmest and May 2012 at 4th warmest.  Include this May in the rankings, and the number two spot now goes to May 2018 at 66.2. The third place occurred in the El Nino Year of 1998 with 65.5. By the way; this May only missed first place /66.5 -1991/ by three tenths /0.3/ of a degree.

Spring Analogues

5.5



DETROITFEBMARAPRMAY
1890-9130.630.848.355.7
1893-9423.640.447.656.3
1898-9919.829.3*45.459.8
1910-1128.833.750.5   64.7 *   4th warm
1917-1824.539.644.662.4
1950-5127.736.546.059.9
1955-5628.132.445.756.0
1971-7224.632.644.660.3
1975-7633.340.450.056.4
1984-8523.438.451.060.1
1999-200031.944.048.061.8
2000-0126.735.151.261.2
2008-0928.538.749.859.4
2011-1232.650.749.4   65.3 * 7th warm
AVE27.437.948.060.0
NORM28.137.249.259.7
DEP-0.70.7-1.20.3


SPRING 2018  TEMPERATURE STATS

Final tally for the Spring Temperatures in Metro Detroit shows; in spite of the second warmest May at 66.2 /norm - 59.7/; the 13th coldest April at 43.0 /norm 49.2/ and colder than average March with 35.4 /norm - 37.2/ cooler than normal still held sway with the spring average temperature coming in a half degree below normal with 48.2/-0.5; /norm 48.7/.


And; was it WET!

Numerous thunderstorms during the month totaled up to 13 thunderstorm days and rainfall of 6.35" making this May the 5th wettest ever recorded. This bumped up against the May's and all time monthly records for thunderstorm days. May of 2004 with all it's flooding rains; totaled up 14 thunderstorm days creating the wettest May on record at Detroit with 8.46". The 14 days of storms also tied June of 1892 and July 1902 for most storm days in May. See more about May of 2004 - and the entire year as a matter of fact - with my Annual Climate Summary 2004 for Southeast Lower Michigan.

Not only was May 2018 wet with nearly double its normal rainfall (6.35"/+3.03) ; so was the entire 2018 spring with 12.77" of precipitation (snow & rain) well above the normal /8.45"/ or  +4.32"!  BTW - Since the beginning of the year; Metro Detroit's running nearly six inches /5.86"/ above the normal of 12.54" with 18.40"! Just in case you were wondering why the lakes were high and the misquotes, rampant.

While on the subject of water:

The Great Lakes are also generally near or higher than last Spring (exception; Lake Ontario which is notably lower) aided by snow and rain across the southern Canadian Basin/Lake Superior region south, across the remainder of the Upper & Lower Lakes. Most notably are the high lake levels from Southern Lake Huron, south into the St Clair River, Lake St Clair, Detroit River into Lake Erie. From the Corp of Engineers late May weekly update:


"All of the Great Lakes are above their long-term average May levels.  Lake Superior is 6 inches above its long term monthly average level for May, and Lake Michigan-Huron is 19 inches above its long term May average level. Lakes St. Clair and Erie are 23 and 24 inches above their long term average levels, and Lake Ontario is 11 inches above its long term average May level. Lake Erie is just 2 inches below its record high May level, which occurred in 1986. Lakes Superior and Michigan-Huron are 9, and 13 inches below their record high, Lake St. Clair is 5 inches below its record high May level, and Lake Ontario is 20 inches below its record high water level that occurred last year. Over the next 30 days, Lakes Superior and Michigan-Huron are forecast to rise by 3 inches. Lake St. Clair is expected to rise one inch, while Lakes Erie and Ontario are forecast to fall by 1 and 3 inches, respectively. See our Daily Levels web page for more water level information".

Check out these recent levels and comparisons:

SUPERIOR
MICH-HURON
ST. CLAIR
ERIE
ONTARIO
Forecasted Water Level for Jun 1, 2018 (feet)
602.07
580.58
576.48
573.85
246.92
Chart Datum (feet)
601.10
577.50
572.30
569.20
243.30
Difference from chart datum (inches)
+12
+37
+50
+56
+43
Difference from average water level for May 1, 2018 (inches*)
+2
+4
+4
+4
+4
Difference from average water level for Jun 1, 2017 (inches*)
-5
+4
+3
+2
-24

Difference from long-term monthly average of Jun (inches)
+2
+16
+21
+22
+8
Difference from highest monthly average of record for Jun (inches)
-10
-15
-8
-5
-22
Year of highest recorded monthly mean
1986
1986
1986
1986
2017
Difference from lowest monthly average of record for Jun (inches)
26
47
50
57
42
Year of lowest recorded monthly mean
1926
1964
1934
1934
1935

Projected change in levels by Jul 1, 2018 (inches)
+1
+2
-1
-3
-3
ALL DATA SHOWN IN THIS SUMMARY ARE REFERENCED TO IGLD 1985
*VALUES FOR SPECIFIC DAY ARE BASED ON 3-DAY DAILY AVERAGE AROUND SPECIFIED DATE
LONG TERM AVERAGE PERIOD OF RECORD, 1918-2017
FORECASTED INFORMATION PROVIDED BY
RECORDED DATA (1918 – present)
FOR MORE INFORMATION VISIT
Department of the Army
provided by
Detroit District, Corps of Engineers
(301) 713-9596
1-888-694-8313 ext. 1













Click here to check the connecting main rivers


___________________________________________________________________________________


SUMMER 2018

After a cool winter and much of the spring until May; the open door to Summer 2018 is upon us. Have we turned the corner from cool to warm (or recently, even hot) weather for this summer?  Reflecting back to our best analogues for the winter might reflect our recent pattern change. This recent change in pattern reminds me of the old adage "Cold Winter - Hot Summer" or is it "Hot Summer - Cold Winter"? 😅 In any event; trends and analogue - not to mention computer guidance, all zero in on more typical summer with maybe a degree or so above the numerical normal for summer.

TEMPERATURES:

All researched data including current trends indicates a typical normal to slightly above summer with temperatures averaging from -0.5 to +1.5 departures across all of Southeast Lower Michigan.


RAINFALL:

All researched data suggests a normal to below normal rainfall summer. While there were a few moderately wet summers, they were at a minimum. The wettest summer by far was the cool and wet summer of 2000 (No repeat, please)! Most summers indicated at least one dry spell, typical for summers in these parts with the majority of analogue years showing one notable (an inch or more) rain deficit month. This would be a drop from current trends thus far this wet year.

HEMISPHERIC TRENDS

The weak La Nina ENSO pattern of last winter is all but a memory as we enter summer, we are entering a Neutral Pattern. The basic Neutral pattern with near normal sea surface temperatures /SST/ should be with us through much of the summer with an edge to a weak El Nino surfacing by late summer but more likely, autumn.

Dynamic and Statistical models have converged on the weak upward sloping trend from a Neutral stance to the beginnings of a Weak El Nino /ENSO area 3.4 at 0.5/ by Autumn.



While the American CFS;v2 model holds a bit tighter to a Neutral stance thru the summer and early Autumn.


What do the computer models paint for the summer?

Most models are generally in remarkable agreement for the summer patterns across the Great Lakes resulting temperatures and rainfall predictions.

TEMPERATURES

Looking at the American CFS;v2 model, the ECMWF European and a combination the ECMWF, UKMET (British to discern from the European) and the French, Meteorological. All models intimate chances are strongest for normal to slightly above normal temperature Summer - matching the going forecast.


RAINFALL

Looking at the American CFS;v2 model, the ECMWF European and a combination the ECMWF, UKMET (British to discern from the European) and the French, Meteorological. All models intimate chances are strongest for normal to slightly below normal rainfall Summer - also, like going forecast




SUMMER 2018 ANALOGUES


SUMMER 2018 ANALOGUES 












DETROITJUNJULAUGSUM AVESUMMERS90 DEG DAYS 

TEMPS
189470.773.969.471.01       N/A
189968.771.572.270.826
191169.573.670.771.3314
191866.671.174.870.8415
195167.872.769.570.017
197670.672.770.771.3521
198562.871.369.267.823
200069.470.370.870.231*
200169.573.574.172.3614
200669.376.172.972.8110
200967.868.971.269.344
201272.379.073.074.8230*
Ave68.872.971.571.1AVE11
Norm69.473.672.071.7NORM       8-12
Dep-0.6-0.7-0.5-0.6















DETROITJUNJULAUGSUM TOTSUMMERSTSTM DAYS

PCPN

18942.632.620.165.411NA/NA
18991.822.950.625.392NA/NA
19111.480.791.313.583NA/5_9/7_6
19183.300.741.295.334NA/5_7/6_8
19513.134.102.9910.22129/7_8
19763.261.471.686.41529/4_7/5
19851.623.964.8810.46237/7_9
20004.905.404.6314.93139/6_7/8
20013.401.162.877.43633/4_5_8/6
20063.954.382.0510.38329/7_9
20095.272.562.7610.59421/5_5
20121.313.672.257.23734/7_8
Ave3.002.822.298.11

Norm3.523.373.009.89TSTMLEGEND
p-0.52-0.55-0.71-1.78First #Annual Total





Second/ThirdHiest





#'sMonth_Total
ColorTempsDegreesRainInches

Legend:Below1.0>Below1.00>NANot Avail

Normal0.0-1.0Normal0.00-1.00


Above1.0>Above1.00>


1911 has been the best Analogue for both winter and spring with temperature departures coming within a tenth or two. Snowfall was also within 5 inches whereas precipitation was drier in the Spring of 1911.
First a word or two about the two new additions on the Analogues...
1 - 90 Degree days; Just what it says, the annual amount of 90 degree days. If the Annual wasn't   available, N/A. * Next to the lowest and highest amount of 90s.

2- Thunderstorm Days; the annual amount of thunderstorm days and highest month and total. If annual is N/A, then month(s) and amount(s) that were the highest.

 Examples     39/6_7/8: 39 thunderstorm days where June and July had 8.
                      NA/5_9/7_6 thunderstorm days Not Available but May had 9 and July 6.

TEMPERATURES

An overwhelming majority of our analogue summers suggest an average or typical summer for this summer. Several "recent" analogue summers (2000 and on) had the overall weak hemispheric patterns similar to our upcoming Summer 2018. Therefore, the ENSO will have little, if any effect on summer patterns and thus, other prevailing patterns are considered. Also not surprising, with such a weak ENSO each analogue summer since 2000 reflects a variety of outcomes; two cool summers, one average and two warm summers. Before these "recent" analogue summers, a preponderance of the summers contained average to below average temperatures. However; it must be noted the norms have warmed the past three decades and thus, the earlier summers would "look" cooler relative to the new norms. The norms for summer have warmed nearly two degrees in the past 50 years since the 1960s because of heat island influences from the city and also; at Detroit Metro Airport. They have also warmed overall with the climatic warming the past 50 years. The normal for the summer in Detroit back in 1960 was 69.9; in 1970 it was 70.4 as opposed to the 71.7 in 2018. Therefore; if we used 70 degrees for the Summer norm, many of the summers would be warmer in departure - it's all relative from the base you are using.

The analogue averages show six normal, three below and two above. The Summer of 2012 was sort of an aberration with it's head start from the very warm spring and drier than average soil moisture; which aided in the summer warmth.


RAINFALL
As discussed above; the research on the model output and analogues suggest a normal to below rainfall summer. It goes against current trend but that doesn't mean a month or even two won't have normal or even above normal rain. What frequently happened during the analogue months was in one or two months; the rainfall was below and strictly speaking - dry spells are quite typical during a summer - see my write-up.

Try to get out and enjoy your summer weather!





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