Unusually low humidity levels across Midwest/Great Lakes

[tropicana]

Chicago IL
Fri Apr 15th 2005

It's a very unusual air mass able to produce relative humidities low enough to flirt with the all-time record. But that was the situation Thursday in Chicago. Humidities here were lower much of the day than in the desert Southwest.
At 6 p.m. Thursday evening, Chicago's relative humidity dropped to just 14%. On only three occasions since weather records began here in 1871--on May 10, 1934, April 11, 1956, and April 8, 1971--has the air been any drier at 13%.
(Thanks to WGN Chicago for that info..good ole Tom Skilling)

In Toronto, the humidity was an unusually low 28% at 4am Friday morning (Apr 15), with dew points at 12F, testimony to how dry the air has been for the last week or so.

-justin-

[PurdueWx80]

This dry air has been torture for my skin - but I'm not complainin' because it's warm, the sky is a GORGEOUS blue, and spring is here. I don't recall ever seeing RH's this low here, nor do I EVER recall seeing relative humidities of ONE PERCENT at 850 mb, like Green Bay had the other day. The big ridge and high responsible for this are almost summer like, and the return flow around the high will eventually bring deep and rich low-level moisture northwards into the Plains. For now the Gulf is shut off though.

Early next week looks to be in the low-to-mid 80's in much of the Midwest, and as the moisture makes it's way northwards, it will clash with an increasingly cool upper system coming out of the west. That means we could see some pretty decent severe weather. This setup reminds me more of July than mid-April. Craziness!

[W13]

I saw the other day that one town in lower Michigan got down to 3% Humidty, and another around the same area to 5% humidty.

Crazy stuff.