Hi Brian-
I have a question regarding the readings for heat index on the main screen.Yesterday my weather station reported a temperature of 90 deg F,but the heat index was only 88 deg F.Is it possible for the heat index to be below the actual temperature? Also,next to the heat index reading is a LED that never changes and is labelled “WMI”. Could you please tell me what that is for and what it does?
By the way,anything over 75 degs in Seattle is a heat wave! 
yep, if the humidity is low… looks like 90 F and 25% rh will do it
http://www.weatherimages.org/data/heatindex.html
the other thing is the MDI light ( modified discomfort index ) if it lights up it is get uncomfortable…
http://www.weather-watch.com/smf/index.php?topic=2429.0
Thanks Virgil83-
Today is suppose to be a record breaker so I will keep my eye on it.My weather station did report 90 deg F but I was not watching the humidity.Either way the heat was a discomfort around here!
Thanks
hi
i dont like the heat index at all myself
i like instead the apparent temperature or humidex
(see under the units setup and under setup, extra and misc setup) to set to show those instead
Interesting.
Now showing a temp of 73.6F and a heat index of 69.1F. Relative humidity is 100%. Would have expected the heat index to be higher than the temp.
Version 10.14i.
Something seems wrong.
Brian
Henderson, NC
Interesting.Now showing a temp of 73.6F and a heat index of 69.1F. Relative humidity is 100%. Would have expected the heat index to be higher than the temp.
Version 10.14i.
Something seems wrong.
Brian
Henderson, NC
not necessarily, the heat index is only “for” over 80 F, so it may not work correctly below that :lol:
I think we need a discussion of exactly what is considered in calculating Heat Index, Humidex, Apparent Temperature, Apparent Temperature Solar, and THSW. THSW was discussed in great detail, with charts and all, elsewhere in a thread here, so that one should be taken care of…
Tom
I am for a discussion, but I think this is discussed somewhere in this boards archives. A while back some character “aardvark” wanted the THSW to be added and we got off on the discussion regarding how this was to be calculated as well as the Steadman paper.
I think what would be nice is to see how what we are calling what with what the NOAA is now using or what the rest of the world uses.
Yep, I was the one who posted the tables and discussions with Davis on THSW in that thread, but it did not cover anything beyond THSW as I recall…
I am for a discussion, but I think this is discussed somewhere in this boards archives. A while back some character "aardvark" wanted the THSW to be added and we got off on the discussion regarding how this was to be calculated as well as the Steadman paper.I think what would be nice is to see how what we are calling what with what the NOAA is now using or what the rest of the world uses.
[quote=“Tcimpidis”]Yep, I was the one who posted the tables and discussions with Davis on THSW in that thread, but it did not cover anything beyond THSW as I recall…
NOAA posts what they call Heat Index on their forecasts… Here is how they compute it:
Heat Index
Heat index or HI is sometimes referred to as the “apparent Temperature”. The HI, given in degrees F, is a measure of how hot it feels when relative humidity (RH) is added to the actual air temperature.
The following equation approximates the heat index. There are many assumptions made produce this, far too many to list here. The equation was obtain by multiple regression analysis and there is a
that would explain everything. It is 75.1F, 47% Humidity, Dew point 53 and the heat index is 78. But the THSW is 89. Normally that shouldn’t be a problem , but mowing the yard the 89 is more realistic thatn the 78.
The heat index seems to indicate just the basics hot or cold, but humidex might be more what should be. with 89 out there, one might think twice on wearing full body armor to take the kids to the playground.
Brian has always, as you know, been for changing things . I would go for something that would in reality tell it likeit is. However, I would assume that at some combination of variables one formula peters out and another needs to kick in at that time.
Thanks to all for the information! I did find a chart on the internet that breaks it all down.After looking at the definitions of heat index verses humidex,I think that Brian is right is staying with the humidex.Anyone interested in the link its http://www.srh.noaa.gov/elp/wxcalc/heatindex.html.
After record heat here the last few days…I am ready to start a discussion on wind chill!
Dale