Summer of 2012
Detroit's Hottest Summer's
So dry was the southern two thirds of Southeast Michigan (especially after a hot and dry July) that the drought index crept up into our back yard. The map below showed the rainfall needed to alleviate the parched conditions by early August, 2012.
As mentioned above, to add insult to injury the dry landscape in 2012 was parched with blazing sun and heat. Actually, this heat occurred in both July 2011 and July 2012!
Summer of 2011 / 2010
While cooler (not making the top ten hottest summers) at Flint and Saginaw, the Summer of 2011's temperature average equaled that of 2010 at Detroit. Note the temperature placement for all three cities for the Summer of 2011 and 2010. Keep in mind, this chart was done before the Summer of 2012..so it is not included. The Summer of 2010 was an all inclusive hot summer for all three cities under the Hottest Summers list at the time.
|Top 20 Coldest/Warmest Summers in Southeast Lower Michigan|
|Rank||Detroit Area*||Flint Bishop**||Saginaw Area***|
Heaviest rains and storms these two summers /2011-2010/ held over the southern tier of Southeast Lower Michigan...mainly from Ann Arbor to Detroit and south to the Ohio border. This led to the second wettest July on record at Detroit with 7.66" in 2011. Curiously, this is not unlike the Summer of 2010 when much of the severe weather and heavy rains also fell south of I-94.
So all this is of the past; what about the future...this summer?
ENSO Conditions are Basically Worthless in Helping Project This Summer's Pattern
Below is the Pacific Sea Surface Temperatures /SST/ projected by the Euro Model for the summer. The concentration of the projections lie in the black rounded rectangle; or immediately south of the 0C line.
The latest ENSO projections have "basically" flat-lined into the summer. Flat-lined meaning they are and are expected to continue nearly dead-on neutral /La Nada/ for the summer. It is difficult enough during the winter season to investigate and project a dominant influence solely based on this sort of pattern; but for the summer, forget La Nada. At least during the winter, other patterns such as the NAO, AO, PDO and PNA are better relied on but in the summer, these too are generally weak and more transitory.
So then; what hints of a summer pattern and forecast is Mom Nature suggesting for this summer?
Recent hemispheric patterns and analogue summers (discussion below) suggest to me a more comfortable summer than the past several. In fact, temperatures should average closer to normal or average between 1.0 degrees below normal to 1.5 degree above. While quite variable, temperature patterns for the summer hint the primary (or likely) temperature pattern for the summer is above normal temperatures early to mid summer with a close secondary (chance) during mid to late summer.
Dominant trends past (previous analogues) and recent (past few months) suggest variability in rainfall trends. April was wet while May was dry relative to normal or average rainfall. While the majority of analogue summers lean toward the dry side; a minority were especially wet! More discussion follows in the analogue section.
We've already seen this wider range variability recently and it looks like it will continue. When speaking of summer's total rainfall; I look for a range of below normal to above normal given the present and past trends. Areas these will occur at this early juncture is very much a crapshoot and only if we go by the recent trends of the spring and subtle analogue trends; heaviest rainfall is intimated to be from the I-96/696 corridor northward through Flint, Port Huron, Saginaw and the Thumb Region.
As the summer ridge builds into the center part of the country, I look for it to oscillate over the Great Lakes and the East, routinely bringing warm to hot weather to the region. However; it should be duly noted that the distinct upper air pattern that has been a key player since mid winter into spring, albeit naturally weakening with time and becoming less frequent, shows no signs of leaving during the summer. I'm speaking of the occasional blocking across the northern latitudes in which I expect to play a distinctive role this summer. By occasionally phasing with weaker mid continental impulses, troughing will dive into the Great Lakes and points east and thus, intermittently deliver enough cooler spells of weather to balance out somewhat, the heat and humidity we do get for a more normal and comfortable summer than the past several.
The ECHAM model below, in my opinion, has picked up on the expected pattern I see evolving based on our recent and analogue pattern. Here I use its projected two meter /surface temperature/ for the country this summer with my estimated upper wind /500 MB/ pressures and flow.
Projected Summer 2013 Temperatures /C/ & Suggested Upper Wind Pattern
As one can see; the analogue summers below represent variable La Nina conditions that transitioned to Neutral.
2013 Summer Neutral Analogues (following variable intensities of La Ninas)
Rainfall and Severe Weather
Look for continuing updates and discussions on the summer pattern throughout the summer.
Summer commences on June 21st, 2013 @ 104 AM EDT. Enjoy the Summer!
Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian