Forecasts are issued three times per week. Two of these will occur on Tuesdays and Thursdays. The third forecast will be posted on either Saturday or Sunday.
Main Forecast Page
The Current Forecast can be viewed by clicking on the link in the left-hand side menu, or by using the calendar in the upper right-hand corner. Previous forecasts can be accessed via the calendar as well, by clicking on the arrows on either side of the name of the month. (NOTE: available forecasts are denoted by colored links).
Clicking on a link to a particular forecast day (See a sample here) will lead one to the appropriate Forecast Summary page for that day's forecast. If needed, Epidemic Updates or Forecast Notes will be highlighted near the top of the page. The Forecast Summary for the stated day / date follows. This consists of a weather description for the next several days and the Risk Prediction (Outlook) for the next two (or three) day's transport events. The Risk Predicition / Outlook on the Forecast Summary page represents the risk to bluemold from ALL of the known sources and is the most important part of the forecasts.
The Outlook portion of the Forecast combines all the aerobiological elements into an evaluation of the risk of disease development. The Threat may be given first. It is a measure of source strength, describing the source's potential contribution to the spread of the epidemic. The given threat rating is color coded corresponding to the likelihood of infection. Red represents the greatest threat, followed by blue and then green. Risk Predictions and the factors pertinent to potential disease development follow the Threat. These factors include sporulation at the source, survivability of the airborne spores, possibility of future deposition, opportunity for infection, and other information that would enhance the understanding of the forecast. One should ALWAYS take into consideration one's local weather and conditions.
Below the General Weather and the combined Risk Predictions is a list of the known sources. A source in this list may be a single diseased field or plant bed; it may represent several sources in a single county; or, it may represent a number of sources in a number of different counties. The latter grouping is usually sources that are geographically clustered together, though the clustering may be quite loose at times. In general, the source groupings are made so that they are as natural as possible and promote the greatest understanding of the forecasts.
For more information visit our Threat and Risks page.
Each source / source region in the list is a link. Following the link will provide details about the transport events from that particular source / source region.
Detailed Source Pages
The links for the individual sources / source regions will contain specifics for the source or sources in question. Note the Date Issued, the Disease Locations (counties/states), and the Trajectory Start(s). Directly under this information is a Trajectory Map. This map shows the path that airborne spores will take when released from the source (or sources) on the indicated date and time. (See a sample here).
A Trajectory Map has several parts. The larger upper map shows the horizontal motion; typically, the small rectangular lower map shows the vertical motion. If one imagines the release point to be the center of a spore cloud, then the forecast trajectory indicates the future pathway of the center of that spore cloud. Along the bottom of the map there is some information about the atmospheric transport simulation.
The release time is in Universal Time on a 24-hour clock, and will be set to correspond to about 10am or 11am local time. In the headings, the SECOND line has the start date and time for the forecast trajectory.
A black star denotes the starting point for the trajectory. After the trajectory starts, there are time/position markers along the forecast pathway. The larger symbols are the 00Z (00 UTC) markers, which corresponds to 7pm EST or 8pm EDT. The smaller symbols are in 6-hr intervals. A time scale is shown below the lower map.
Alternate Displays
Presentations on the larger horizontal map may vary depending on the status of the epidemic and the forecast situation. Other trajectory maps include ...
Multiple sources on one map: These appear during heavy epidemics. All the trajectories are for the same day; all the trajectories will be the same color. See a sample here.
Trajectories from one source at multiple starting heights: One can specify the starting height above ground for each trajectory. Most trajectories posted in the forecast start at 200m above ground. However, the Forecaster frequently runs trajectories at other starting heights to guide analysis and evaluation of the transport events. Sometimes it aids understanding to post these in the forecasts; for example, when there is significant horizontal spread of the airborne spores. A maximum of three heights is allowed. The red trajectory is the lowest starting height, the next-higher is blue, and the highest (if there are three) is green. See a sample here.
THINGS TO REMEMBER
The forecast trajectories and the resulting Outlooks are most useful if you keep in mind the following:
-
Sporulation occurs at night and the spores are released anytime from 8 AM through 1 PM. The trajectory start at 10 AM is just before maximum spore release. However, spores released at other times of the day may follow other tracks, especially if the weather situation is changing rapidly.
-
The pathway you see on the map is the anticipated path for the spore cloud CENTER. The spore cloud will actually spread away from the center. The areas on either side of the trajectory pathway will also be vulnerable.
-
There is a limit to the detail and accuracy of the weather forecasts. If you are in a potentially higher risk area, be sure to pay close attention to your local conditions!
-
Finally, these forecasts may be viewed from a different perspective. They can't tell you exactly where the spores will go, what the exact weather will be, or if you'll definitely receive viable spores deposited on your fields. They can, however, do a very good job of telling you where the spores WON'T go, what the weather WON'T be, and when you likely WON'T have to worry about inoculum arriving in your fields from known sources. This information should be helpful in making decisions about control strategies using protectant fungicides.
If you have any questions, please contact the Forecast Center.
Return to Blue Mold Forecast Homepage