The two main features discussed in my last couple of blogs for the summer will continue the battle this week across the central and eastern part of the country.
Another impressive polar impulse diving south and phasing with a strong Pacific jet wind max over the northern part of the country, will bring a radical shift in the weather pattern late this week. This projected upper air development will give the boot to our present hot and steamy weather by surging a more comfortable air mass into the area late this week. Daytime high temperatures will fall off into the 70s to near 80. In the meantime however; waves of upper energy will ripple through the very unstable air mass over the region the next several days and act as the "match for the dynamite" in place. Strength of storm development will be determined by the dynamics of the atmosphere, instability available and to a lesser extent; timing of the storms. In addition, the risk of very heavy rains and local flooding will come with any of the rougher storms, especially when training over the same region.
Strong to severe thunderstorms are possible overnight Monday through early Thursday as the energy impulses push through the northern and eastern part of the country. Later in the week on Thursday; a strong cold front, spawned by the shift in the Polar jet will barrel toward the Great Lakes later Wednesday and clear through the region on Thursday.
An earlier model run during this past weekend /Sat-GFS/ intimated severe
squall-line development for later this week with even an argument for a derecho type
of system affecting several states. Since then, projections have backed
off some but still a few rounds of severe weather with damaging winds
are possible across much of the region.
Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian
6/24/13
6/11/13
Occasional Stalling Fronts, Possible Severe Weather And/Or Heavy Rains Highlights Our Early Summer As Dominant Upper Air Pattern Hangs Tuff!
In the last few weeks, our weather pattern across the country has been exactly what the late winter into spring pattern suggested in conjunction with wetter analogues in my Summer Outlook. The headline above tells the story along with normal to below normal temperatures. Why? Put simply; the rather strong upper low and troughing periodically slipping into place over southeastern Canada has and continues to block summer-like air masses from fully taking over our region for more than just a few days. And thus, this conflict of the upper jet along with summer-type air masses and associated humidity that periodically set up a battle ground to our south this spring; has now crept north into the Lakes Region.
This upcoming projection of this Friday's upper jet stream shows an example of this well with the Canadian jet winning out at this time. Note; the warm jet stream surging from the southwest and southeast sections of the country while the quasi-stationary cool polar trough remains anchored over central to eastern Canada. This "conflict of interests" in air masses has created a battle zone (on map in green) this spring into early summer which is now showing signs of lifting north the past few weeks. This certainly would be expected by this time so that's not unusual. What is more the question "Will this continue for a longer duration and if not; which upper air feature will dominate the rest of the summer?" Typically, one would expect the upper ridge to become the more dominant with summer-time advancing but as our analogues suggested, this was not always the case and we either ended up with a cooler summer (with the Canadian trough holding) or a normal to warmer than normal summer as the upper ridge pushed more often into the region. In addition; now that Great Lakes Region has been brought into the conflict zone; the question of how wet will the summer become is also up for grabs.
From the original Outlook:
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.
Rainfall and Severe Weather Rainfall averaged decidedly below normal in the analogue set with about 75% below normal...a strong trend. However; the remaining years were very wet and while a minority of years, it still is an important subset of wet years! This suggests to me that the pattern portrayed in my hemispheric discussion could lead to a stalling of the frontal conflict and storminess and thus, runs the risk of repeating in the same general region. While analogues state drier summers prevailed; we still run the distinct risk of a stormier summer including training echoes if the pattern happens to stall in our neck of the woods.
We have just entered this conflict zone the past few weeks which has brought above normal rainfall since late May. Much of May itself was very dry with all regions painting 1.5"- 2.0" below normal until the last week when roughly up to two inches fell. Another one to two inches (or more) has fallen since June 1st so we are off to a good start
for the growing season now. And latest indications suggest this pattern will persist for the time being.
Weekly Weather
Just this week we had one impulse slide over and to our south Monday which generated heavy rains across the region, with a second due shortly later Wednesday into Wednesday night. This low pressure and attendant warm and cold fronts is expected to ride near the Tri-State border of Indiana/Ohio/Michigan by Wednesday evening. Perhaps close enough to bring not only heavy rains but possibly severe weather as the very warm, tropical like atmosphere steams up over the Ohio Valley and runs rudely into our cooler, more stable air over the central Great Lakes Region (sound familiar).
The Storm Prediction Center has Southeast Lower Michigan outlined for the potential of severe weather Wednesday and Wednesday night with a greater risk over the Ohio Valley.
http://www.spc.noaa.gov/products/outlook/day2otlk.html
Stay alert to the NWS-DTX for any watches or warnings Wednesday and Wednesday night. Pop over here for a slide presentation from DTX for the potential for severe weather Wednesday into early Wednesday night.
Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian
This upcoming projection of this Friday's upper jet stream shows an example of this well with the Canadian jet winning out at this time. Note; the warm jet stream surging from the southwest and southeast sections of the country while the quasi-stationary cool polar trough remains anchored over central to eastern Canada. This "conflict of interests" in air masses has created a battle zone (on map in green) this spring into early summer which is now showing signs of lifting north the past few weeks. This certainly would be expected by this time so that's not unusual. What is more the question "Will this continue for a longer duration and if not; which upper air feature will dominate the rest of the summer?" Typically, one would expect the upper ridge to become the more dominant with summer-time advancing but as our analogues suggested, this was not always the case and we either ended up with a cooler summer (with the Canadian trough holding) or a normal to warmer than normal summer as the upper ridge pushed more often into the region. In addition; now that Great Lakes Region has been brought into the conflict zone; the question of how wet will the summer become is also up for grabs.
From the original Outlook:
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.
Rainfall and Severe Weather Rainfall averaged decidedly below normal in the analogue set with about 75% below normal...a strong trend. However; the remaining years were very wet and while a minority of years, it still is an important subset of wet years! This suggests to me that the pattern portrayed in my hemispheric discussion could lead to a stalling of the frontal conflict and storminess and thus, runs the risk of repeating in the same general region. While analogues state drier summers prevailed; we still run the distinct risk of a stormier summer including training echoes if the pattern happens to stall in our neck of the woods.
We have just entered this conflict zone the past few weeks which has brought above normal rainfall since late May. Much of May itself was very dry with all regions painting 1.5"- 2.0" below normal until the last week when roughly up to two inches fell. Another one to two inches (or more) has fallen since June 1st so we are off to a good start
for the growing season now. And latest indications suggest this pattern will persist for the time being.
Weekly Weather
Just this week we had one impulse slide over and to our south Monday which generated heavy rains across the region, with a second due shortly later Wednesday into Wednesday night. This low pressure and attendant warm and cold fronts is expected to ride near the Tri-State border of Indiana/Ohio/Michigan by Wednesday evening. Perhaps close enough to bring not only heavy rains but possibly severe weather as the very warm, tropical like atmosphere steams up over the Ohio Valley and runs rudely into our cooler, more stable air over the central Great Lakes Region (sound familiar).
The Storm Prediction Center has Southeast Lower Michigan outlined for the potential of severe weather Wednesday and Wednesday night with a greater risk over the Ohio Valley.
http://www.spc.noaa.gov/products/outlook/day2otlk.html
Stay alert to the NWS-DTX for any watches or warnings Wednesday and Wednesday night. Pop over here for a slide presentation from DTX for the potential for severe weather Wednesday into early Wednesday night.
Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian
6/2/13
After Several Hot Summers; Finally a More Comfortable Summer in 2013?
Do Recent Atmospheric Conditions Foretell Our Summer?
The past three summer's across Southeast Lower Michigan have been bears at times for heat and misery. The Summer of 2012 was not only hot it was rather dry early in the season and thus, it was a tough growing season where water was not readily available. Beneficial rains came too late and too much, especially north of I-69 where heavy rains led to the wettest August on record at Saginaw with 9.3"
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.
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?
Temperatures
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.
Rainfall
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.
Hemispheric Patterns
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
Summer Analogues
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)
Temperatures
Rainfall and Severe Weather
Summer commences on June 21st, 2013 @ 104 AM EDT. Enjoy the Summer!
Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian
Summer of 2012
Detroit's Hottest Summer's
Rank
|
Average Temp.
|
Year
|
1
|
74.8
|
2012
|
2
|
74.8
|
2005
|
3
|
74.5
|
1995
|
4
|
74.5
|
1955
|
5/6
|
74.4
|
2010/11
|
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!
Average Temperature Records for July
Detroit
|
Flint
|
Tri-Cities
|
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*** | |||||||||
| Coldest | Warmest | Coldest | Warmest | Coldest | Warmest | |||||||
| Temp | Year | Temp | Year | Temp | Year | Temp | Year | Temp | Year | Temp | Year | |
| 1 | 66.5 | 1915 | 74.8 | 2005 | 65.4 | 1992 | 74.2 | 1933 | 64.8 | 1915 | 73.0 | 1933 |
| 2 | 67.0 | 1992 | 74.5 | 1995 | 66.1 | 2009 | 74.0 | 1934 | 65.1 | 1992 | 73.0 | 1931 |
| 3 | 67.3 | 1927 | 74.5 | 1955 | 66.2 | 1958 | 72.7 | 1936 | 65.5 | 1982 | 72.5 | 1955 |
| 4 | 67.5 | 1875 | 74.4 | 2010/11 | 66.3 | 1960 | 72.6 | 1939 | 65.8 | 1945 | 72.3 | 1995 |
| 5 | 67.6 | 1903 | 74.2 | 1988 | 66.5 | 1969 | 72.6 | 1931 | 65.9 | 1950 | 72.1 | 1930 |
| 6 | 67.8 | 1985 | 74.0 | 1933 | 66.6 | 2004 | 72.6 | 1921 | 65.9 | 1924 | 72.1 | 1921 |
| 7 | 67.9 | 1912 | 73.8 | 1949 | 66.7 | 1985 | 72.3 | 2010 | 66.1 | 1985 | 72.0 | 2010 |
| 8 | 67.9 | 1907 | 73.7 | 1921 | 66.8 | 1972 | 72.3 | 1949 | 66.4 | 2009 | 72.0 | 1988 |
| 9 | 68.1 | 1982 | 73.6 | 1952 | 66.8 | 1967 | 72.2 | 1955 | 66.4 | 2004 | 72.0 | 1937 |
| 10 | 68.2 | 1972 | 73.5 | 1991 | 66.9 | 1962 | 72.0 | 1935 | 66.4 | 1979 | 71.9 | 1936 |
| 11 | 68.3 | 1979 | 73.5 | 1959 | 66.9 | 1927 | 71.9 | 1938 | 66.5 | 1977 | 71.7 | 1998 |
| 12 | 68.3 | 1902 | 73.5 | 2002 | 67.0 | 1982 | 71.8 | 1988/11 | 66.6 | 1951 | 71.5 | 1934 |
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?
Temperatures
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.
Rainfall
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.
Hemispheric Patterns
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
Summer Analogues
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)
Note: years where the la Nina to neutral pattern occurred for the second time in two year
or so are denoted with a “2” following the year. Normals used 1971-2000 for related years.
Analogue Trends Seen
Temperatures
The Neutral analogue summers are really
quite mixed on the temperature front this time which is hardly surprising given the hemispheric and SST environment. Even though Detroit’s summer data
favors normal to below normal temperatures, one must closely compare this data to
Flint and Saginaw. The reason being, the normals at Detroit were increased in the
past few data sets (1971-2000 & also 1981-2010) due to mainly the effect of
the local heat island that now encompasses the Detroit Metro Airport; whereas Flint
and Saginaw saw little change in their normals. This would logically then, skew
Detroit’s departure temperature data down somewhat. In any event; analogues suggest normal temperatures will prevail.
Rainfall and Severe Weather
Rainfall averaged decidedly below normal in the analogue set with about 75% below normal...a strong trend. However; the remaining years were very wet and while a minority of years, it still is an important subset of wet years! This suggests to me that the pattern portrayed in my hemispheric discussion could lead to a stalling of the frontal conflict and storminess and thus, runs the risk of repeating in the same general region. While analogues state drier summers prevailed; we still run the distinct risk of a stormier summer including training echoes if the pattern happens to stall in our neck of the woods. In conjunction with this kind of scenario; there is more likelihood of a wider range of rainfall amounts from below normal to above over Southeast Lower Michigan.
Look for continuing updates and discussions on the summer pattern throughout the summer.
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
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