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    Inversion Forecast



    Discussion

    Discussion Last Updated: 02-28-2017 7:14:11 pm MST

    A cold and active weather pattern closed out February. As we head into March, model ensembles are in good agreement that an extended period high pressure will dominate the region through the first 10 days of the month. Inversions are likely to form across the northern valleys during this period. The good news is that extended daylight hours and solar intensity will prevent the formation of strong, shallow, inversion layers. With more convective mixing and deeper inversion depths, air quality will remain much better than we saw during the beginning of February.

    This product is being developed by researchers at the Utah Climate Center. Using output from the National Center for Environmental Prediction’s (NCEP) Climate Forecast System (CFSv2), this technique projects surface inversion probability for persistent inversion events—defined as events lasting longer than 4 days—with a demonstrated “skill” over a span of ~ 30 days. A surface inversion probability of 35% or greater suggests a statistically significant likelihood of an extended event. It should also be noted that inversion forecasts, in and of themselves, are not air quality projections. The projection is valid for a radius of roughly 200 miles around Salt Lake City.

    Image Interpretation: The blue bar graph shows the calculated Surface Inversion Probabilities. Values above the horizontal yellow line (~35% on the right axis) have a statistical significance of manifesting as persistent (> 4 days) inversion events. The solid black line above the SIP chart shows the ensemble average of 200mb geopotential heights for the most recent 16 CFSv2 forecasts. The individual dotted lines are individual model runs. The vertical red and yellow lines identify the initialization (+0) and 30 day (+30) locations. SIP values lying within this 30 day window have a statistically significant confidence interval. Values before the initialization data are obtained from NCEP reanalysis data.

    For more information on the methodology and origins of this product, see the following publication here.