7/15/15

Don't Panic! You'd Never Know it by the Weather But Climatological Summer is Already Half Over; Now What about the Second Half?

The first six weeks of summer are in the books (and you couldn't prove it by me) but where have been all the typical hot days of summer? Even though June averaged around normal; the notably cool July thus far with temperatures averaging 2 - 4 degrees below normal has certainly taken a bite out of the heat! In addition, only ONE 90 degree day has been officially registered at Detroit - in June no less; (none, officially at Flint nor Saginaw). This has made it seem like we have been in a perpetual June pattern for weeks, not dead-center summer or what if typically called the Dog Days of summer.

"Dog Days of summer is the name for the most sultry period of summer, from about July 3 to Aug. 11. Named in early times by observers in countries bordering the Mediterranean, the period was reckoned as extending from 20 days before to 20 days after the conjunction of Sirius (the dog star) and the sun."

The expected upper wind pattern across the country discussed in the Summer Outlook has verified extremely well for the first half of the summer with the two moderately strong jets (Polar and Pacific) occasionally phasing and vying for dominance.

A good example of the prevailing jets expected this summer (see further below); also shows on the map below, taken from a recent model prog panel. Note the persistent oscillating North American pattern thus far this summer (as described in the Summer Outlook). The Pacific jet continues sending shortwaves into the mid part of the country, which flatten the summer ridge only to occasionally phase with the Polar short waves digging south into the eastern half of the country. There has been no shortage of storms and severe weather this warm season where one, or both of these jets pass over the country. Though occasionally getting clipped with severe weather in Southeast Lower Michigan (most notable June 22-23rd), we have missed the bulk of the severe weather to a large extent as heat and humidity bubbles up across the Midwest and Ohio Valley; only to be shunted east many times just south of the Lakes Region. This has been courtesy of our friendly Polar Jet which also has made summer temperatures quite tolerable (see maps below). Looking ahead to the second half of the summer in this regard, I would expect the upper ridge to give more equal showing than the first half, providing Southeast Lower Michigan more summer-like temperatures and resulting storms. At the same time, the Polar jet shows she's here to stay; routinely visiting through the rest of summer.



From the Summer Outlook:

Summer 2015


Glancing at the upper wind projection for the Summer of 2013 show similarities to this summer and differences. The difference noted for this summer 2015 projection is the better subtropical jet projected and thus, a more variable upper ridge strength. This is a result of building and flattening ridging in response to short waves riding in and through the region from the west. This is depicted on both maps with the first a computer generated 500 Heights and my interpretation of active areas of surface patterns. The second map, my interpretation of summer dominant and placement of air masses. 




 


Broadening this summer discussion out a bit, the first half of summer (or the first six weeks); temperatures across Southeast Lower Michigan have averaged a "comfortable" 69 at Detroit; 68 1/2 at Flint and 68 at Saginaw. A quick average and rounding gives us an average for the first half of the summer of ~ 68 1/2. Delightful temperatures none-the-less if you like a comfortable summer; which is just so happens what the analogues called for in the Summer Outlook.

Analogues favor the cooler side of normal which seems reasonable considering upper wind patterns over Canada and El Nino trends. The analogue summers were extremely variable but with definite trends within with four cooler than normal, six normal and two warmer with a generally a comfortable summer projected. Not surprising, the average temperature while in the normal range, leaned a bit toward below normal - makes perfect sense with twice as many cooler than warmer summers. This is not surprising as El Nino Summers lean toward the cooler side of average. Also, the chances of long hot spells are less than average and subsequently; average to below average /8-12/ so too are the amount of 90 degree days.  

In defense of the summer weather thus far, looking at the actual statistics and norms it may also surprise you that even though the summer's been on the cool side, the summer hasn't been all that terribly cool, statistic-wise. While temperatures have averaged around 68 1/2 across the ENTIRE region, it's the departure from normal at Detroit which makes it seem much cooler. Detroit's normal are skewed UP about 1 1/2- 2 degrees higher than the normals at either Flint or Saginaw due to the heat island. June norms are as follows: 69.4/ 66.5/ 67.2 respectively and July normals include the following; 73.6/ 70.5/ 71.0 for Detroit, Flint and Saginaw. Those stats alone show the preference for a metro Detroit warmer heat island. Realistically speaking if no heat island existed at Detroit, the normal at Detroit IMHO should be only about a degree or so warmer than Flint and Saginaw.  Therefore; the average temperature across Southeast Lower Michigan for the first six weeks is running roughly a degree below normal when all three locations are averaged together and separately; Detroit ~ -2.2, Flint and Saginaw area ~0.4 degrees

If we briefly scan the 20 coolest summers list at all three locations and even if we continued to average right where we are now for the rest of the summer; only Detroit just nicks the top 20 list of all three locations. If we average just near normal the rest of the summer, temperature averages would rise some.

                                  Again Detroit's at about 69, Flint's 68 1/2 and Saginaw 68 thus far

                                  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 1931
2 67.0 1992 74.8 2005 66.1 2009 74.0 1934 65.1 1992 72.9 1933
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
8 67.9 1907 74.0 1933 66.8 1972 72.3 1949 66.4 2009 72.0 2010
9 68.1 1982 73.8 1949 66.8 1967 72.2 1955 66.4 2004 72.0 1937
10 68.2 1972 73.7 1921 66.9 1962 72.0 1935 66.4 1979 71.9 1988
11 68.3 1979 73.6 1952 66.9 1927 71.9 2011 66.5 1977 71.9 1936
12 68.3 1902 73.5 1991 67.0 1982 71.9 1938 66.6 1951 71.7 1998
13 68.3 1891 73.5 1959 67.0 1950 71.8 1988 66.8 1946 71.5 1934
14 68.4 1889 73.5 2002 67.1 1965 71.7 2012 66.9 1965 71.5 1932
15 68.5 1883 73.5 1931 67.1 1945 71.7 1995 66.9 1962 71.4 2011
16 68.7 1917 73.2 1944 67.2 1997 71.7 2002 66.9 1917 71.4 1959
17 68.8 1924 73.0 1987 67.4 1951 71.7 1987 67.0 1958 71.2 1973
18 68.8 1904 73.0 1919 67.4 1957 71.6 2005 67.0 1926 71.2 1949
19 68.9 1967 72.9 1953 67.4 1924 71.6 1983 67.2 1972 71.2 1919
20 69.1 1897 72.9 1930 67.5 2000 71.3 1944 67.3 1981 70.9 2005
* Detroit Area temperature records date back to November 1874.
** Flint Bishop temperature records date back to January 1921.
*** Saginaw Area temperature records date back to January 1912.

 

Average Temperature Departure maps

JUNE

 JULY 1-14

 

While heat has been lacking this summer thus far, rainfall has NOT; especially across the southern counties of Southeast Lower Michigan!

RAINFALL                         

Location                                 Amount                                 Norm    Dep
Detroit:   SINCE JUN 1      6.25                      4.95   1.30
FLINT:    SINCE JUN 1      7.64                      4.44   3.20  
SAGINAW   SINCE JUN 1      5.74                      4.11   1.63

To maintain the integrity of my Summer Outlook; the second half of the summer should be drier across the Saginaw Valley and Thumb region while normal to above rainfall continues across the southern two thirds, since all areas are now above.

 

Rainfall:



I look for rainfall to be quite variable as mixed data presents conflicting results and where and how much may also be exasperated more than what is typical for many summers. Taking all data (past and present) into account; rainfall is expected to be above normal over the southern sections of Southeast Lower Michigan and normal to possible even below across the Saginaw Valley and Thumb Region. As with temperatures, timing of the wettest and driest periods will be quite variable - not unlike the spring. 

Also; This is similar to 2013 where heavy amounts were seen over the south and lighter, below normal amounts were observed in the Saginaw Valley and Thumb.

 

Rainfall Totals Departure maps:

The wet June stands out like a sore thumb, a subtly drier pattern has begun to emerge in July - and mainly in the Thumb/Saginaw Valley region - BUT it is too early to call it a trend and we'll stick by the original forecast. I'll give my original summer forecast time to hopefully work out for all areas.


 

And with that, this brings me to my Outlook for the Remainder of the Summer

And, to that - little overall change to my original call with Temperatures averaging 1 1/2 below to 1 1/2 above normal while rainfall is above across the southern sections (Flint area to Port Huron south the Ohio border) and normal to below across the Saginaw Valley and Thumb Region. Most areas should see adequate rains this summer if past and future is any guide.

Temperatures overall (and this should balance out the first half some), I look for warmer temperatures on average with more normal to above normal the second half of the summer as upper ridging gains some ground - so don't count the summer out just yet!


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

7/12/15

NICE AND BRIGHT TO BLACK AS NIGHT; THE 35th ANNIVERSARY OF THE JULY 16TH, 1980 DERECHO

Step back in time on the 35th anniversary of one of the most notable derechos ever to clobber Southeast Lower Michigan from Ann Arbor into Metro Detroit; The July 16th 1980 Derecho! With the numerous severe weather outbreaks along with the severe winter weather of the mid 1970s to early 80s; I was fast becoming a seasoned veteran to rough weather in Southeast Lower Michigan during my formative years with the National Weather Service.
 

NICE AND BRIGHT TO BLACK AS NIGHT!

THE JULY 16TH, 1980, DERECHO

Written by: William R. Deedler, Weather Historian
Originally written:
July 22nd, 2005/Updated July 2015
 
The word "derecho" may sound unfamiliar or its use in meteorology relatively recent in nature, but the word actually was brought into meteorological vernacular way back in 1888. Dr. Gustavus Hinrichs, a physics professor at the University of Iowa, was given that credit when he used the word, derecho, in a paper he had published in the American Meteorological Journal in 1888. Dr Hinrichs chose this terminology for thunderstorm induced straight-line winds as an analog to the word tornado. Derecho is a Spanish word which can be defined as "direct" or "straight ahead" while tornado is thought by some, including Dr. Hinrichs, to have been derived from the Spanish word "tornar" which means "to turn". This definition and other derecho facts are taken from the Storm Prediction Center's About Derechos web page, which contains many interesting facts and background studies about derechos.

Even though the term "derecho" dates back well over a century, it has only been relatively recent (since the 1980s) that more investigative studies and research has greatly increased our knowledge about these types of storms. Derechos are associated with a line of showers or thunderstorms that are often "curved" in shape on radar and satellite. These bowed out storms are called "bow echoes". A derecho can be associated with a single bow echo or multiple bow echoes. By definition winds in a derecho must meet the National Weather Service criterion for severe wind gusts (greater than 57 mph) at most points along the derecho path. In the stronger derecho events winds can exceed 100 mph.

Southeast Lower Michigan has had several derechos in the past, but certainly one of the more memorable ones plowed through extreme Southern Michigan during the forenoon hours of Wednesday, July 16th, 1980.

Summer of '80 starts out on a chilly note

The Summer of 1980 actually hadn't been much of a summer as far as warm temperatures and dry weather were concerned. The summer had been unseasonably cool and soggy into early July. June's average temperature was a relatively chilly 63.7 degrees, making it the eighth coolest June on record at Detroit. To add insult to injury, not only had June been cool, it also had been very wet. June's monthly rainfall totaled up to nearly six and a half inches /6.42"/, making it the sixth wettest June on record, which undoubtedly made the month seem even worse.

While the first few weeks of July averaged a bit below normal, some good ole' fashion summer-time heat finally began to bubble up into the region by mid month. Hot and unstable air pushed its way north into the Great Lakes by the 15th as temperatures surged into the lower to mid 90s. Up until that time, only once before had temperatures pushed up into the 90s that summer. The arrival of the hot and humid air mass set off some scattered showers and thunderstorms on the 15th, but really nothing of consequence compared to what would generate to the west overnight.

Birth of a Hybrid Derecho 

 



The low pressure area with attending warm and cold fronts pushing through the Upper Midwest (see above map) was responsible in igniting the derecho at the surface late on the 15th. Thunderstorms developing over extreme Eastern Iowa and Northern Illinois during the very early morning hours of the 16th, intensified and formed into a squall line that pushed through Northern Illinois between 3 AM and 5 AM EDT. The storms were spawned out ahead of the frontal system as it approached northern Illinois, mainly ahead of the triple point juncture and nearly perpendicular to the warm front. At the same time, a potent mid level short wave and wind max (approx 60-70 knots) surged east across the Upper Midwest toward the Southern Great Lakes.

Nice and Bright to Black as Night

The derecho surged quickly east across Northern Indiana and Southern Lake Michigan with a measured wind gust of 98 mph at the St. Joseph Coast Guard as it blasted onshore in Southwest Lower Michigan! While the sky was relatively bright at sunrise over Southeast Lower Michigan, a band of foreboding clouds advanced in quickly from the west, covering the celestial dome. As the forceful storms and associated hurricane force winds approached the area, several observers remarked about the horrid dark green color the sky took on as the squall moved overhead. In fact, numerous people over the years have commented about the "dark pea green sky" that accompanied the July 16th 1980 storm. The green color in the sky may have been reflective of the low sun angle at the time (the derecho moved through region between 730 and 930 AM EDT) and abundance of moisture in the low clouds. It got so dark that many street lights were triggered and popped on over portions of the region. Severe thunderstorm warnings were issued over the region though some remarked: "it happened so quickly and early in the day, it caught us off guard".

The hardest hit regions across Southeast Lower Michigan were Washtenaw and Wayne counties, extending mainly from the Ann Arbor area east into southern sections of Detroit (or south of the Ford Road /M-153/ corridor). While the wind officially gusted to 71 mph at Detroit Metro Airport, much higher winds were reported in other areas in the strongest core of the derecho.

As one person who witnessed the swath of damage across southern portions of Washtenaw and Wayne counties, the following excerpts from storm data relay the incredible outcome of the storm. In the storm data below, the derecho is referred to as a downburst. In addition, the derecho was accompanied by a small tornado as it exited extreme Southeast Lower Michigan. Tornadoes can occur in isolated thunderstorm supercells ahead of the derecho producing squall line or they may be associated with the squall line itself.


STORM DATA
Counties in
SE Mich
Date
7/16/80
Time
830-920AM EDT

Washtenaw
Wayne
Monroe
"Intense downburst developed just west of Ann Arbor. Path of the most intense damage across southern Ann Arbor then eastward through the Downriver suburbs of Detroit. Winds estimated up to 100 mph in Washtenaw county, up to 150 mph in Wayne County. Innumerable buildings, vehicles and trees destroyed in eastern Washtenaw, central and southern Wayne, and northeastern Monroe counties. Several boats were swamped on the Detroit River. Power off in some areas up to ten days."

Downriver CommunitiesDate
7/16/80
Time
910 AM EDT

Allen Park, Lincoln Park, and Ecorse, in Wayne county "Railroad cars blown off track in both directions in Allen Park. Department store roof blown sideways in Lincoln Park. Funnel sighted over Detroit River from Canadian shore. Tornado damage included in, and hardly distinguishable from large area of straight line wind damage. Funnel continued eastward several more miles into Canada".
It's amazing that after reading about the force of the wind and subsequent damage, that only one person - a woman - was reported injured in sort of a freak accident when the wind forced her into a revolving door! Note the following that was taken from "Derecho Hazards in the United States" by Walker S. Ashley, Climatology Research Laboratory at the University of Georgia, Athens, Georgia. It gives an interesting account of the July 16th,1980 Derecho storm damage relative to other storm damage.

Fujita and Wakimoto (1981) provided extensive documentation of the 16 July 1980 derecho that produced widespread damage across large areas of Michigan, Illinois, Wisconsin, and Minnesota. They indicated that this storm produced approximately $650 million in damage as it traversed the four-state region. Accounting for inflation (to 2003 dollars), this storm produced an estimated $1.3 billion in damage from strictly straight-line winds. This estimate exceeds many damage tallies from U.S. hurricanes and is larger than the inflation-adjusted damage estimates from all major tornadoes that have affected the U.S. since 1890 (Brooks and Doswell 2001). This single event illustrates that derecho damage can exceed the damage from most hurricanes and tornado events affecting the contiguous U.S.

Note the graph above which displays monthly damaging wind events in the U.S. July and June are the top months for wind storms. Many of these wind storms occur as derechos over the Great Lakes states (Johns and Hirt, 1987).


Look for an excellent detailed paper on the Derecho of July 16th 1980 by Dr. Fujita in 1981 here

Detroit Climate Observation for July 16th, 1980


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

7/8/15

Grand Daddy of all Southeast Michigan Heatwaves!

THE "GRAND DADDY" OF SOUTHEAST MICHIGAN HEAT WAVES 

                                             July 8th - July 14th, 1936

 (originally written in the late 1990s with updates 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

6/23/15

Severe Weather Outbreak of June 22-23, 2015

The severe weather event we were up against was well televised by our meteorological models and, at least in my point of view, could have been worse given the projected instability, shear in many lower levels of the atmosphere and over all strong dynamics and winds aloft. I mentioned July 2nd, 1997 and July 7, 1991 as one of the previous severe weather events it reminded me of when forecast by the guidance. One major difference was timing as with both previous July events; the cold front moved through at or near peak heating. Another factor was the disruption and stabilizing factor, at least somewhat, of the warm front and attending storms that pushed through mid-late afternoon. These storms developed on the old storm outflow boundary set up the night before, generated over the upper Midwest. The cloud and rain debris was also responsible for a mainly cloudy day (another limiting factor) on Monday even before the afternoon storms.

All in all, it was a memorable event with four tornadoes and numerous severe thunderstorms spawned Monday into the early morning hours of Tuesday. One tornado touched down just east of Birch Run /EF2/, another in the vicinity of Decker/Deckerville /EF1/, a third just north to northeast of Manchester /EF1/ and a fourth, just southwest of Emmet /EF0/. A fifth tornado hit Portland /EF1/ over Southwest Michigan earlier on Monday afternoon.

See report from the NWS-DTX

Mesonet Storm Report



6/21/15

Update 6/22/15 930p - Conflicting Air Masses of "Dynamite" Potential Set for Monday Into Early Tuesday Morning

Update 930 P

Round -2 The Cold Front Action

Fasten you seat belts; it's gonna be a bumpy night!!!

http://www.spc.noaa.gov/products/watch/ww0338.html
 URGENT - IMMEDIATE BROADCAST REQUESTED
   TORNADO WATCH NUMBER 338
   NWS STORM PREDICTION CENTER NORMAN OK
   915 PM EDT MON JUN 22 2015

   THE NWS STORM PREDICTION CENTER HAS ISSUED A

   * TORNADO WATCH FOR PORTIONS OF 
     NORTHEAST ILLINOIS
     NORTHERN INDIANA
     SOUTHERN LOWER MICHIGAN
     NORTHWEST OHIO
     LAKE ERIE
     LAKE HURON

   * EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 915 PM
     UNTIL 300 AM EDT.

   * PRIMARY THREATS INCLUDE...
     A COUPLE TORNADOES POSSIBLE
     SCATTERED DAMAGING WINDS AND ISOLATED SIGNIFICANT GUSTS TO 75
       MPH POSSIBLE
     SCATTERED LARGE HAIL AND ISOLATED VERY LARGE HAIL EVENTS TO 2
       INCHES IN DIAMETER POSSIBLE

   SUMMARY...THUNDERSTORMS ARE LIKELY TO INCREASE IN COVERAGE AND
   INTENSITY THIS EVENING AS A STRONG UPPER JET AND COLD FRONT APPROACH
   THE REGION FROM THE WEST. A WARM AND VERY MOIST AIRMASS ACROSS THE
   WATCH AREA WILL FUEL ROBUST STORM UPDRAFTS AMIDST INTENSIFYING
   DEEP-LAYER WIND FIELDS. THIS SHOULD SUPPORT BOTH SUPERCELL AND
   FAST-MOVING LINE SEGMENTS WITH DAMAGING WINDS...LARGE HAIL...AND
   POSSIBLY A COUPLE TORNADOES.

   THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 70 STATUTE
   MILES NORTH AND SOUTH OF A LINE FROM 35 MILES NORTH OF MOUNT
   CLEMENS MICHIGAN TO 45 MILES NORTH OF CHAMPAIGN ILLINOIS.  FOR A
   COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
   UPDATE (WOUS64 KWNS WOU8).

   PRECAUTIONARY/PREPAREDNESS ACTIONS...

   REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
   TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
   AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
   THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
   AND POSSIBLE WARNINGS.

   &&

   OTHER WATCH INFORMATION...CONTINUE...WW 335...WW 336...WW 337...

   AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
   SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
   WIND GUSTS TO 65 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
   500. MEAN STORM MOTION VECTOR 27035.



Update- 145P
Round -1 Warm Front Action

As discussed yesterday, as the warm front approaches this afternoon and early evening, the old meso-complex of storms ignited overnight ahead of the front will continue to advance into Southeast Lower Michigan. The air mass ahead of the complex is moderately to strongly unstable along with upper wind Bulk Shear in the neighborhood of 50 knots. This has weakened from earlier readings of 75 knots and is depicted by a general weakening of the storm complex as of early afternoon. Non-the-less as the old storm complex/outflow moves into more favorable conditions it's identity should be maintained enough and thus the issuance of Severe Thunderstorm Watch. #333

Reasons for the watch from SPC:

...GREAT LAKES/MIDWEST REGION...
   A LARGE -- BUT GRADUALLY WEAKENING -- MCC CONTINUES MOVING ACROSS
   THE GREAT LAKES/MIDWEST ATTM...CENTERED OVER SRN WI/NRN IL AND LK
   MI.  STORMS HAVE INTENSIFIED OVER THE PAST HALF HOUR IN THE SRN LK
   MI/SWRN LOWER MI AREA INVOF A SHARPENING WARM FRONT...AND EXPECT
   POTENTIAL FOR STORM REDEVELOPMENT ACROSS THIS AREA -- AND SWD INTO
   ADJACENT NRN IL/NRN INDIANA -- AHEAD OF THE MAIN MESOSCALE LOW
   ASSOCIATED WITH THE MCC.  ALONG WITH RISK FOR STRONG/DAMAGING WINDS
   AND HAIL...A COUPLE OF TORNADOES WILL ALSO BE POSSIBLE -- GIVEN
   PRESENCE OF THE AFORMENTIONED WARM FRONT AND STRENGTHENING FLOW
   ALOFT WITH TIME.

No change in blog through tonight!
_______________________________________________________________________________
6/21/15

In my Summer Outlook; I stressed the likelihood of impressive jet stream conflicts along with their attending surface air masses outcomes with wetter, stormier conditions for most of the region at least part of the summer depending on air jet stream/air mass dominance. It's been notably active to our south and west all season.

"Summer as a rule can be one of the more difficult seasons to forecast for because of the lighter, variable upper wind jet dominance. This summer that general trend may not apply as much as two dominant upper wind patterns via for center stage; a relatively strong polar jet that has had no trouble visiting the Great Lakes throughout the spring along with the sub-tropical/tropical jet aided by an ever increasing El Nino. Overall; I look for temperatures to average around normal but with notable swings as the upper low and troughing in eastern Canada via for dominance against upper ridging, aided and at times, even suppressed by El Nino affected winds across the south. This is a difficult forecast as we dealing with two distinctive upper wind patterns, not always present in such fashion in the summer." 



Both the GFS and  NAM Models have been strongly suggesting we have the above to contend with - in spades- Monday into early Tuesday morning while the European has been somewhat weaker with the overall system. Latest 12Z guidance of the Euro now intensifies the low center to 988MB by the time it reaches Ontario Tuesday morning.

Thus far; this severe weather season has been intermittent and on the slow side as Southeast Michigan has remained much of the time in the more stable air masses, aided at times by the cold to cool Lakes and easterly fetch as systems approach from the southwest.The dynamics, upper and lower strong wind jets along with the instability, deep layer shear and CAPE/LI's projected this time are further north over Wisconsin and Lower Michigan and are quite strong. In fact, this time around the worst (or best depending on your point of view) severe weather dynamics look to be coming together just to our west and northwest Monday night and Tuesday morning, then advecting into our region during the very early morning hours of Tuesday. One caveat to limit severe weather after warm frontal passage and before the cold front approaches in the overnight hours will be the warmer air pulled north aloft into the strong system to our northwest and thus, this will provide a temporary cap against the development of severe weather. At this time, it looks as though the dynamics of the system along with cooler air aloft (both advected in and slight overnight cooling aloft) with aid in eroding any cap that does form by the time the cold front approaches Tuesday morning. All severe weather risks are here, including strong damaging winds and tornadic cells and may be realized for at least some. At this time, we have two general periods of severe weather potential - warm frontal and cold frontal.

Warm Front Risk

Never trust a warm front! I learned that early on back in the some of the stormy 70's summers and a even more notable case was the Frankenmuth tornado and flash flooding. Ironically,  the Frankenmuth Tornado occurred on this date; June 21st, back in 1996. I remember it well as I was working along with two other METS and the newly installed Doppler Radar was still in its infancy having been installed in the early 1990s. While leery of the warm front draped over Southeast Lower Michigan, most eyes were watching the cold front and severe weather possibility over Wisconsin with a watch box issued for that region. As the atmosphere cooled aloft, thunderstorms and very heavy flash flooding rains popped like popcorn in the proximately of the warm front. Helicity values and instability were notable along the warm front and thus, helped spawn the infamous tornado.

Therefore; this is definitely something that has to be watched with this aforementioned system with both the warm front and cold front as helicity/EHI values are extremely high promoting tornado risk! The biggest negative is while all this "dynamite" exists, will it become lit or realized? It could become negated if part or all of Southeast Lower Michigan becomes too warm aloft which inhibits thunderstorm growth. At this time, with the warmer air rushing in aloft and best dynamics northwest, the risk of severe weather with the warm front will be marginalized (become capped) but can not be ruled out and bears watching until the warm front clears the area!

GFS Maps:






 SPC's Take


Jun 21, 2015 1730 UTC Day 2 Convective Outlook
Updated: Sun Jun 21 17:32:26 UTC 2015 (Print Version | 20150621 1730Z Day 2 shapefile | 20150621 1730Z Day 2 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Probabilistic
 Population  Cities  CWAs  Interstates  Counties  ARTCC  FEMA Regions
 
Categorical Day2 0600Z Outlook
Day 2 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 129,731 27,151,847 Chicago, IL...Detroit, MI...Milwaukee, WI...Toledo, OH...Madison, WI...
SLIGHT 143,283 14,682,662 Cleveland, OH...Minneapolis, MN...Buffalo, NY...St. Paul, MN...Fort Wayne, IN...
MARGINAL 190,594 20,003,960 Indianapolis, IN...Columbus, OH...Kansas City, MO...Pittsburgh, PA...Rochester, NY...
 Forecast Discussion
   SPC AC 211732

   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1232 PM CDT SUN JUN 21 2015

   VALID 221200Z - 231200Z

   ...THERE IS AN ENH RISK OF SVR TSTMS GREAT LAKES AND UPPER MS
   VALLEY...

   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE UPPER MIDWEST TO LOWER
   GREAT LAKES...

   ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF THE N-CNTRL/NE
   STATES...

   ...SUMMARY...
   SCATTERED SEVERE STORMS ARE LIKELY ACROSS PARTS OF THE UPPER
   MISSISSIPPI VALLEY AND GREAT LAKES REGIONS...SOME OF WHICH SHOULD BE
   INTENSE...MAINLY FROM MIDDAY THROUGH THE EVENING ON MONDAY.

   ...UPPER MS VALLEY/GREAT LAKES...
   STRONGLY CONSIDERED AN UPGRADE TO MODERATE RISK WITH POTENTIAL FOR
   CLUSTERS OF INTENSE SEVERE STORMS WITH ALL SIGNIFICANT SEVERE
   HAZARDS POSSIBLE. BUT WILL DEFER GIVEN ENOUGH UNCERTAINTY WITH
   REGARD TO EVOLUTION OF LATE D1 CONVECTION WITH ITS SUBSEQUENT EFFECT
   ON THE DEGREE OF DOWNSTREAM DIURNAL DESTABILIZATION...ALONG WITH
   TIMING OF THE PAIR OF MID-LEVEL SHORTWAVE IMPULSES WITH RESPECT TO
   PEAK HEATING.

   GUIDANCE IS CONSISTENT IN DEPICTING STRENGTHENING
   LOW/MID-TROPOSPHERIC FLOW IN RESPONSE TO A CONVECTIVELY-GENERATED
   MCV FROM LATE D1/EARLY D2 AND APPROACH OF AN UPSTREAM SHORTWAVE
   TROUGH CURRENTLY OVER THE SRN CANADIAN ROCKIES. THESE FEATURES WOULD
   ENHANCE LOW-LEVEL WAA OF THE RICHLY BUOYANT AIR MASS CURRENTLY
   PRESENT OVER THE LOWER MO VALLEY. AVAILABLE CAMS VARY MARKEDLY WITH
   THE DAYTIME EVOLUTION OF AN MCS EXPECTED TO BE ONGOING ACROSS PARTS
   OF SRN MN/NRN IA. IT SEEMS PLAUSIBLE THAT THIS ACTIVITY SHOULD
   PERSIST THROUGH THE DAY WITH AN ORGANIZED SEVERE RISK ON THE EDGE OF
   A ROBUST PLAINS EML. THIS TYPE OF SCENARIO MAY RESULT IN LEAD
   CONVECTION OUTPACING THE MORE FAVORABLE THERMODYNAMIC ENVIRONMENT
   CHARACTERIZED BY RATHER STEEP MID-LEVEL LAPSE RATES AND VERY LARGE
   BUOYANCY. 

   AT LEAST SCATTERED UPSTREAM TSTM DEVELOPMENT SHOULD OCCUR BY LATE
   AFTERNOON ALONG THE COLD FRONT FROM CNTRL/ERN WI SW TO THE IA/IL
   BORDER AREA AS CONVERGENCE ALONG THE FRONT AND DIABATIC HEATING
   OVERCOME INHIBITION DUE TO THE INITIALLY STOUT EML. SUPERCELLS ARE
   EXPECTED IN INITIAL STAGES OF DEVELOPMENT...WITH SOME OF THIS
   CONVECTION GROWING UPSCALE DURING THE EVENING. WITH LOW-LEVEL FLOW
   BECOMING INCREASINGLY VEERED IN THE WAKE OF THE LEAD MID-LEVEL
   IMPULSE...MAIN HAZARDS WITH SW EXTENT SHOULD BE VERY LARGE HAIL
   TRANSITIONING TO PREDOMINATELY SEVERE WIND. WHERE 850 MB WINDS CAN
   REMAIN QUITE STRONG WITH ENLARGED LOW-LEVEL HODOGRAPHS /MOST LIKELY
   IN ERN WI TO LOWER MI/...A RISK FOR STRONG TORNADOES AND/OR
   SIGNIFICANT SEVERE WIND GUSTS MAY DEVELOP.

   ..GRAMS.. 06/21/2015


Part Two: The Cold Front

The second villain in the piece (and possibly the worst) will be the strong cold front as it sails east-southeast at 45 to 50 mph through lower Michigan during the overnight hours of Monday into early Tuesday. As the storms approach, the intense wind max moving through the region at all upper levels will help push any storm development and line eastward of upwards of 50-60 mph aiding some very turbulent storm downdrafts creating scattered high wind damage. The risk of tornadic cells will gradually decrease with time as wind directions at all levels align with straight line high winds remaining the main risk.

This entire system reminds me of a few of our stronger squall lines including bow echoes and derechos; May 31st, 1998 (which is also an analogue), also July 7th 1991 and July 2nd 1997 because of the tornado threat. I'm sure there are others, too numerous to mention. Again the dynamite appears to be there and whether of not the extreme weather conditions materialize will be an up to the minute realization. Models are predicting one of the stronger severe weather events in recent times as the dynamically driven system runs rudely into explosively unstable air mass. I wouldn't be surprised in SPC upgrades some of the area to a moderate risk if these parameters continue in successive model outputs. Keep tuned to NWS web page/NWR and other weather mediate outlets during the day Monday into Tuesday morning!

I will update any notable changes as usual through the period.

GFS Maps:










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