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
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:
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.
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 | ||||||
| DETROIT | JUN | JUL | AUG | SUM AVE | SUMMERS | 90 DEG DAYS |
| T | E | M | P | S | ||
| 1894 | 70.7 | 73.9 | 69.4 | 71.0 | 1 | N/A |
| 1899 | 68.7 | 71.5 | 72.2 | 70.8 | 2 | 6 |
| 1911 | 69.5 | 73.6 | 70.7 | 71.3 | 3 | 14 |
| 1918 | 66.6 | 71.1 | 74.8 | 70.8 | 4 | 15 |
| 1951 | 67.8 | 72.7 | 69.5 | 70.0 | 1 | 7 |
| 1976 | 70.6 | 72.7 | 70.7 | 71.3 | 5 | 21 |
| 1985 | 62.8 | 71.3 | 69.2 | 67.8 | 2 | 3 |
| 2000 | 69.4 | 70.3 | 70.8 | 70.2 | 3 | 1* |
| 2001 | 69.5 | 73.5 | 74.1 | 72.3 | 6 | 14 |
| 2006 | 69.3 | 76.1 | 72.9 | 72.8 | 1 | 10 |
| 2009 | 67.8 | 68.9 | 71.2 | 69.3 | 4 | 4 |
| 2012 | 72.3 | 79.0 | 73.0 | 74.8 | 2 | 30* |
| Ave | 68.8 | 72.9 | 71.5 | 71.1 | AVE | 11 |
| Norm | 69.4 | 73.6 | 72.0 | 71.7 | NORM | 8-12 |
| Dep | -0.6 | -0.7 | -0.5 | -0.6 | ||
| DETROIT | JUN | JUL | AUG | SUM TOT | SUMMERS | TSTM DAYS |
| P | C | P | N | |||
| 1894 | 2.63 | 2.62 | 0.16 | 5.41 | 1 | NA/NA |
| 1899 | 1.82 | 2.95 | 0.62 | 5.39 | 2 | NA/NA |
| 1911 | 1.48 | 0.79 | 1.31 | 3.58 | 3 | NA/5_9/7_6 |
| 1918 | 3.30 | 0.74 | 1.29 | 5.33 | 4 | NA/5_7/6_8 |
| 1951 | 3.13 | 4.10 | 2.99 | 10.22 | 1 | 29/7_8 |
| 1976 | 3.26 | 1.47 | 1.68 | 6.41 | 5 | 29/4_7/5 |
| 1985 | 1.62 | 3.96 | 4.88 | 10.46 | 2 | 37/7_9 |
| 2000 | 4.90 | 5.40 | 4.63 | 14.93 | 1 | 39/6_7/8 |
| 2001 | 3.40 | 1.16 | 2.87 | 7.43 | 6 | 33/4_5_8/6 |
| 2006 | 3.95 | 4.38 | 2.05 | 10.38 | 3 | 29/7_9 |
| 2009 | 5.27 | 2.56 | 2.76 | 10.59 | 4 | 21/5_5 |
| 2012 | 1.31 | 3.67 | 2.25 | 7.23 | 7 | 34/7_8 |
| Ave | 3.00 | 2.82 | 2.29 | 8.11 | ||
| Norm | 3.52 | 3.37 | 3.00 | 9.89 | TSTM | LEGEND |
| p | -0.52 | -0.55 | -0.71 | -1.78 | First # | Annual Total |
| Second/Third | Hiest | |||||
| #'s | Month_Total | |||||
| Color | Temps | Degrees | Rain | Inches | ||
| Legend: | Below | 1.0> | Below | 1.00> | NA | Not Avail |
| Normal | 0.0-1.0 | Normal | 0.00-1.00 | |||
| Above | 1.0> | Above | 1.00> |
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!
Making weather fun while we ALL learn,
Bill Deedler - SEMI_WeatherHistorian
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