Early Summer Upper Air Pattern Simulates Preferred Computer Guidance and Analogues as Calendar Summer Solstice Commences

The actual upper air and surface pattern during the month of June thus far has displayed well the expected pattern in my Summer Outlook based on analogues and prevailing computer guidance. The upper low winds prevailing over eastern Canada and upper ridge winds in varying positions over the States; have been oscillating in unison bringing cool and occasionally hot conditions into the Great Lakes. The north wind flow associated with the jet stream into the Canadian Upper Low has been exceptional resulting in a periodic push of cool, comfortable air with low humidity southeast, sometimes well into the eastern third of the country.

Just to recap the original Summer Outlook:

TEMPERATURES

I look for the summer to average around normal or -1.0 to +1.5 degrees of the new 1991-2020 normals in Southeast Lower Michigan. The summer seems to be shaping up to be a more changeable summer than is typical in both temperature ranges and weather patterns. The push of cooler air from Canada should offset most hotter spells from the south. 

RAINFALL

Though analogues display a slightly drier summer when all data is considered; in following the overall recent rainfall patterns, a normal to wetter summer is more likely.

As one can see; the CFS forecasted the upper prevailing height/wind pattern displayed below well for the beginning of the summer, anyway. From the Summer Outlook for Southeast Lower Michigan:

 

So what does the most recent upper level run display for the GFS 384hr run display for the U.S.? This pattern has been more or less forecasted into early July.

 

It is easy to see the persistence of the upper Low and associated troughs over Eastern Canada (and push of cooler air) into the Great Lakes and into the southeast while at the same time; breaks in the cooler pattern resulting of zonal to southwesterly flows of warm to hot weather behind the high pressure from the Plains and Midwest bringing hot, muggy air intermittently ahead of the next cold front.

Note; the surface pattern associated with the upper wind flow into early July. Warm to hot air masses are routinely dampened by varying intensities of cold fronts; weak to strong. Depending of strength of the cold front, available moisture and timing of day will create rainfall over the region and possible severe weather. Of course; this is just one run of the GFS but it contains the trend and does foretell the continuance of  current upper air pattern right through the July 4th weekend and beyond.

 

Up through the first three weeks of June and meteorological summer, temperatures have bounced from around normal to below - to above - and back below - and above erratically. Maybe not surprisingly temperatures have averaged close to normal all over Southeast Lower Michigan. In Detroit with an average of 69.0 degrees; the temperature is just three tenths above normal /0.3/ through the 20th. Flint's averaging 65.6 degrees or three tenths below normal /-0.3/; while Saginaw is at 66.7 /-0.2/. In addition; the Summer Solstice just occurred this morning; Tuesday, June 21, 2022, at 5:14 A.M. EDT.

To just give one an idea how erratic the temperatures have been over Southeast Lower Michigan; low temperature readings fell into the 40s and 50s over the weekend only to sharply rebound to near or at record highs today. Thus far today it looks like Detroit tied the 96 degree record of 96 back in 1933. On the flip-side, Flint fell to a record low Sunday morning of 43 - /old record of 44 - 1959/ and then popped to 95 degrees two days later today, Tuesday - /record still stands 98 in 1923/.

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