4/10/13

The Battles Of Spring Are In The Air!

Finally some spring-like thunderstorms pulsed through Southeast Lower Michigan this second week of April. Along with the storms; very heavy rains soaked the mainly dormant landscape. Just a hint of green has been activated by the spring rains thus far, and mainly just grassy areas at that. Late you say? It's almost laughable when think back to last year at this time when our spring green-up was already over a month old. But last year of course was the truest of anomalies; the warmest March and early spring on record. Also while you're thinking back, you might remember, April settled down back closer to normal and averaged cooler than March! Extraordinary indeed! In addition, you might also remember the cold air masses in April that brought the killing frosts and freezes and heavily damaged the fruit crops. Well hopefully, we'll have none of that this year as we slowly warm and the growth appears, somewhat more gradual. After all, which is better; exhaust the cold air now or wait till the buds/flowers are on the fruit trees and spring growth is in full term?

But what of this spring? What spring you may ask? Oh it's there but you have to look closer for it. It's a whole different kind of spring...the inverse of last year...closer to our "normal spring" but thus far, it has indeed been colder and later. While March ended up 2 to 2 1/2 degrees below normal; April thus far has been worse! During the first third of the month /10 days/, temperatures have averaged as much as 3 to nearly 5 degrees below normal with the biggest departures up around the Saginaw Valley and Thumb District. Yes, when mother nature pays back; she can be a....   


The Great Lakes continue their icy chill as domes of cold, residual Siberian and Arctic air surge down, nearly unabated across the northern and even central states at times. This Arctic air continues to be funneled down across the Lakes; accentuating the typically early spring icy waters of the Great Lakes. And, as you can see by the widespread 30s to around 40 degree water temperatures as we approach mid April; the Great Lakes at this time of year do absolutely nothing in aiding our spring warm-up.

 
Arguably; no other weather map displays the spring air mass battle more appropriately than our present surface map for 8pm this evening; Wed Apr 10th. The battle line is clearly drawn, seen and heard by way of strong thunderstorms and very heavy rains along the quasi-stationary front draped west to east across the Lower Lakes/Upper Ohio Valley. Cold, residual Arctic air continues to be funneled down across the Great Lakes while at the same time, spring's warm southerly winds in response to an increasingly stronger spring sun, push northward up through the deep south and into the Ohio Valley! The resultant, strong baro-clinic zone also denoted by the sharp east/west temperature contrast across the region is exceptional; 30s and 40s to the north and 50s, 60s and 70s around and immediately to the south...all in a very tight area of landscape. 



The clash of the seasonal air masses; winter to the north and spring to the south indeed is in the air and will be for the next few weeks anyway as the cold, winter-like air masses slowly warm and moderate as they clash with springtime warmth. Our extended maps indicate this with a rather busy weather period for the next 10 to 14 days. I'll be on watch for more notable Mother Nature rou's or tantrums in the meantime.

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