"Dan Luke" spewed this drivel:
"Matt Barrow" wrote:
The same day it hit 104 in Chicago and ...the humidity was 90+/-
percent.
Baloney.
Look at a psychometric chart:
http://www.rfcafe.com/references/gen...tric_chart.htm
Ever hear of "Heat Index"?
Yes.

What's that got to do with your made-up statement that the temperature was
104 F. and the humidity was 90%?

Did you attempt to understand the chart?

First off, it's psychRometric.

Do you understand relative humidity?

According to NOAA, July of 1995 (about which I presume Matt is talking)
had the following (from
http://www.crh.noaa.gov/lot/science/jul1395/jul1395.htm)
quote
In the immediate Chicago region, surface dew points held in the upper
70s to near 80 however the temperature exceeded 100 degF for several
hours. Heat Index values were greater than 115 degrees for much of the
midday and afternoon hours...reaching 125 degrees for the 2145UTC
observation from Midway (MDW). In fact, the mercury remained at or
above 100 degF at MDW for seven hours, from 13/1800UTC to 14/0100UTC.
This extraordinary length may be partially due to the more urban
location of the field.
/quote

Now, I am going to use the following readings:
104 degrees F for the temperature (the "official" high)
80 degrees F for the dew point.

According to the formula RH =~ 100((112 - .1T - Td)/(112 + .9T))^8,
where T = observed temperature and Td = dew point temperature, I get a
relative humidity of 88.32%.

P.S. A heat index of 125!?!? That's definitely "stay at home and hope
the AC doesn't go out on me" weather!