24 Hour Threat Forecast
What is it?
The "24 Hour Threat Forecast" provides information about conditions that may adversely affect the roadway over the next 24 hours. This forecast is created from weather and road surface models and aims to predict threats along the roadway that may impact travelers, including potentially hazardous road conditions, precipitation, and blowing snow.
A main goal for the threat forecast is to provide some information about projected road conditions for the next 24 hours. Another purpose is to supplement the regular road conditions report as made by state personnel. It is currently not possible to have road conditions continually updated. Sometimes it will have been hours since conditions for a segment were last updated, and in such cases the presence (or absence) of a threat forecasts for the beginning of the forecast period may provide additional information about the current state of the roadway.
This information is a forecast, and as is true with any forecast the actual conditions may differ from what is predicted. Local conditions in an area or an unexpected change in the weather may make roads worse than forecasted at a given time, or maintenance actions performed on a road may leave it in better condition than had been forecasted. The presence of a threat forecast does not guarantee that threat will be observed or be exactly as described, nor does the absence of a threat forecast guarantee hazardous road conditions will not occur.
How is the information provided?
On the road conditions map, the threat forecast can be viewed by choosing the option to view the base layer that includes the threat forecast. That can be done by selecting the appropriate option from the base layer menu to the right of the map. To turn off the threat forecast, select the base layer option without it.
Also, when there is meaningful information somewhere within the state a link will be available over the map to activate the threat forecast map. That link functions exactly the same menu option. When viewing the threat forecast on the map there is a link over the map that will turn off the forecast view.
When the threat forecast layer is turned on, sections of road having threats to report for some time across the forecast period are shown on the map with a thick pale yellow shading encompassing the regulart road condition lines. Roads without the yellow outline when that layer is turned on do not have a current threat forecast to report.
In the two below images, one shows the regular road conditions view with the radio button at right and link at the top of the map that can be used to turn on threat forecast base layer on the map, and the other shows the threat forecast active with the yellow shading on the affected roads and the radio button at right and link at the top of the map that can be used to turn back off the threat forecast base layer.
|Regular Road Conditions Base Layer||Threat Forecast Conditions Base Layer|
The details of the threat forecast are shown in the segment report provided when selecting a road segment from the map. This include brief listings of what conditions and where and when they are anticipated. That information is available within the segment report whether the threat forecast base layer is on or not. If a segment has threats to report, those are available whenever that segment is selected to view its report.
Examples of threat forecast report content
For any given span of road with threats forecasted over the next 24 hours, the report will describe in general terms the type of conditions and the timeframe over which those conditions are anticipated to occur. This content is provided in a section labeled "24 Hour Threat Forecast" immediately below the "Conditions" section. If the section is absent for a segment there is nothing to report for it for that section of road.
Consider a threat forecast from about 4pm on a Monday. These messages could occur within road segment reports viewed at that time.
The following message indicates roads may be snowy and/or icy for the area described from the current time to about 9am Tuesday.
The following message indicates roads may be snowy, slushy, and/or icy for the area described from about 1am Tuesday through at least the end of the 24 hour forecast period.
The following message indicates roads may be somewhat icy for the area beginning about 11pm Monday and occurring through about 3am Tuesday.