A Cool Week is In-Store for Southeast Lower Michigan - Hold Off Planting Vulnerable Plants This Earth Day Week

After a relative slow slow start to April warmth; the past couple of weeks have more than made up for the cool start to spring thus far. With March averaging 2 - 3 degrees below normal, the growing season was put on hold into early April. However since April 9th, temperatures have averaged consistently above or well above normal these past 10 days or so. So much so, that the average temperature thus far April is now averaging in the upper 40s to lower 50s - or about 4 degrees ABOVE normal. The last time freezing temperatures were seen and felt was early in April on the 6th at Detroit /32/, and the 11tth at Saginaw /32/ and 12th at Flint /also 32/. In fact, sometimes it has been safe to start planting hardier crops mid to late April. Cool weather crops such as peas, broccoli, cabbage, etc etc can be usually put in at least by late April.

Therefore; is it safe to plant?

I would definitely hold off planting anything frost/freeze sensitive that will germinate the next week to 10 days. A pronounced cool spell through this upcoming week anyway, will definitely take a bite out if that above normal average temperature accumulated this month. A return upper wind flow, back cross Polar will take  hold this week. This pattern is much like the bitter cold, cross Polar flow seen recently in mid to late winter. Of course, the air has moderated some since then and will continue as the solar angle increases with the spring but will still carry a punch. Frost, freezes and possibly even a period or two of snow flurries are all in our near term weather scenario. The outcome will depend on the actual coldness of the air mass over the region and whether or not cloud, cover dissipates overnight allowing for good radiational cooling along with local temperature affects.

 
As noted in my map above, Earth Day is this Wednesday. It is what it says, a day to reflect on our mother planet and to appreciate our life giving environment. Earth Day began in the early 1970s as we became more and more concerned about our pollution of environment and the longer term affects.

Earth Day Flag

Next up - Record Breaking Late Spring Snowstorms & What's May looking like?

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