What does this warning mean?

I’m getting an email warning that says:
WARNING: 3000 max GDD was reached!

I reviewed the threads on GDD, but that number seems very high. Is that a yearly total, or monthly? What is the significance? Should I be getting the same warning every day?

Thanks,
David.

Full text of message:

[quote]******WEATHER WARNING ******

3000 max GDD was reached !

Time of event was : 7:00:08 AM
Date of event was : 05/22/06
Current conditions :
Windspeed 1.1 mph
Direction WSW 252

Hi,
You have reached the max number of Growing Degree Days.
If you don’t care about GDD turn the switch off. :wink:
Control Panel> Warning Alerts & E-mail> Alarm Thresholds tab
near the bottom of the page.

Explaination of GDD…
http://www.wunderground.com/about/faq/degreedays.asp


gdd.GIF

Thanks Gus. What I was looking for was the significance of the 3000 (default) setting. Are there charts or tables that explain what insects reach maturity after what growing degree day? How about garden plants? Are there guides to maturity based on GDD?

The 3000 point seemed to be close to the point of mosquito activity around here, but flies, bees and other bugs have been active for some time now. Any ideas?

Check this for insects and GDD
http://extension.unh.edu/agric/GDDays/Docs/growch.pdf

Looks like GDD is important in several areas. Other uses GDD…
Crop and pest management
http://www.ipm.iastate.edu/ipm/degreeday/
http://www.sws.uiuc.edu/warm/cropdata/
Crop maturity
http://ohioline.osu.edu/agf-fact/0101.html
Growing Degree Days (GDDs) and Corn Heat Units (CHUs)
http://www.canola-council.org/gdd.aspx
Turf management
http://www.gddtracker.net/

Thanks for helpful links Gus. Now, I am more puzzled about the current reading, which as I said originally, seems a bit high.

Since I have the settings to start calculation on May 10th (13 days ago) and the current reading is 3539 (see screen shot) that means that my average GDD would have to be 272 degrees per day!

I know it may be a bit warmer out west, but that seems excessive. For example on the Ohio State site, they say:

The GDD accumulations for the growing season in Ohio range from less than 2500 GDD in northeastern counties to more than 3000 GDD along the Ohio River in southwestern Ohio

Now Weather Display, seems to be saying I’ve had over 3,000 GDDs since May 10th.
What’s wrong with the data?

Even if it was ignoring my May 10th setting and calculating all they way back to Jan 1, the formula is:

Formula: GDD = (T High plus T Low) divided by 2, minus 50

And we’ve had about 173 days so far, that would still be an average of 20 GDD per day through the winter and spring - meaning the AVERAGE temp of every day so far had to be 70 degrees. (50 + 20)

Am I missing something or is WD confused?


David,
From your screen shot on 5/23…

“Current reading at (7am every day): 3539.0 F”

Indicates an increase of 539 since the warning at 7AM on 5/22 (one day earlier).
That’s one very hot day even for Death Valley. :wink:
I think something might be wrong with the calculation.

This thread has been continued as a Bug Report here