New Web Images:
|http://weather.gov/mdl/gfslamp/uncertform.php||(Uncertainty plots - station selection page)|
|http://weather.gov/mdl/gfslamp/uncertplots.php||(Uncertainty plots - direct access)|
|http://weather.gov/mdl/gfslamp/threshplots.php||(Threshold plots - direct access)|
Q: How are the thresholds determined?
A: The thresholds are statistically derived as part of the LAMP developmental process. They vary by element, element category, cycle, projection, region, and season.
Q: What do the different categories mean on the Uncertainty Plots?
A: The "uncertainty categories" convey whether or not a probability exceeds its corresponding threshold and its proximity (whether above or below) to that threshold. For a specific explanation of each category, see the table below:
|No||Probability is below the threshold by ≥ 10%|
|Chnc||Probability is below the threshold by < 10%|
|Lkly||Probability exceeds the threshold by < 10%|
|Yes||Probability exceeds the threshold by ≥ 10%|
Q: Why are some categories missing for ceiling height and visibility?
A: The ceiling height and visibility categories displayed on these sites were chosen in correspondence with the MVFR, IFR, and LIFR flight categories. Not every category for ceiling height and visibility is displayed, but only those relating to these specific flight categories. To determine the best category forecast, LAMP considers all categories, beginning with the most rare. To see the official LAMP categorical forecast, please refer to the text bulletin page.
For additional help with understanding and using the Uncertainty and Threshold plots,
please see the following link: