In light of the recent cold weather, the Kansas Mesonet has enhanced and expanded its Freeze Monitor tool, providing new resources for both producers and agents dealing with extended cold temperatures. The page can be found at https://mesonet.k-state.edu/airtemp/min/hoursbelow/ or by navigating through the Mesonet menu (? > Weather > Freeze Monitor).
Figure 1. Screenshot of the updated Freeze Monitor on the Kansas Mesonet.
Background
While the original Freeze Monitor focused on how many of the past 24 hours were spent in freezing conditions, our new tool expands its scope to the past 14 days. This allows us to track a lengthy cold spell, not just the overnight lows. The tool is focused on the most recent freeze event, or the continuous time below 32°F. It also handles continuous time below 24° and 12°.
We built this tool to answer the following questions:
How many hours have we spent below freezing?
The default map and table display the length (in hours) of the most recent freeze event. The bottom dropdown “Change Threshold” selector allows for the selection of 24° (for wheat) and 12° (for canola) as well. As a new feature, desktop users will find navigation buttons above the map to switch between temperatures and mobile users will find that all maps are accessible by swiping right and left on the map.
When was the last cold spell?
Once things warm up, selecting the “Days Since” map from the middle dropdown “Change Map Type” selector will display the number of days (up to a year) since the temperature last dipped below 32°F (or 24° or 12°). It also changes the table to include freeze climatology: the normal and record dates of first or last freeze.
How cold did it get?
Select “Low Temperature” from the middle dropdown “Change Map Type” selector (mobile users can also swipe left until they reach the Low Temperature maps). The displayed map and table show the coldest temperature during the latest freeze event in the past two weeks. Note that as each threshold may have a different time period, the lowest temperature for each may vary.
Did we break a record?
Please refer to our daily max and min temperature page at https://mesonet.k-state.edu/weather/maxmin/ (also found under the Mesonet homepage menu at ? > Weather > Wind Gust and High/Low)
What if I’m interested in a different threshold?
This page introduces a new tool under the “Calculate” tab for those who want a different threshold. Users can select both the threshold and the time period, and the number of hours below will automatically update. Note that this calculation sums all hours below the threshold levels, not continuous hours.
Figure 2. The Calculate Tab allows users to set a custom threshold and time range.
What about the freeze before last?
When temperatures regularly dip below freezing, the Freeze Monitor will only report the most recent freeze event. The Chart tab gives a graphical representation of temperatures, and the Calculate tab provides the number of hours for any time period in the past two weeks.
Figure 3. Chart displaying past two weeks’ temperature data for a single station.
What happened to the old Freeze Monitor?
For the sake of continuity, we will continue to serve our original Freeze Monitor page through spring. Both new and old pages include a link at the top to reach the other. We will retire the old Freeze Monitor over the summer. If you have concerns, please contact one of the authors at the end of the article.
About the Data
Temperatures are air temperature data measured at Kansas Mesonet stations at 2 meters (6’5”) above the ground. Data displayed are the hourly average temperature. Timestamps refer to the hour ending on the timestamp. The page is updated hourly as new data become available. The “Download” tab has links to comma separated (.csv) data for the entire network and individual stations. It also includes image files (.png format) of all maps on the page. For more information on the impacts of cold temperatures on wheat and canola, see the “Resources” tab.
Dan Regier, Web Developer - Kansas Mesonet
regierdp@ksu.edu
Christopher Redmond, Assistant Meteorologist - Kansas Mesonet
christopherredmond@ksu.edu
Mary Knapp, Assistant State Climatologist
mknapp@ksu.edu