
Gusty winds and dry conditions will continue to bring fire weather concerns to the southern Plains through Friday. Severe thunderstorms including a few tornadoes, large hail and damaging wind gusts are expected across parts of the Midwest and lower Ohio Valley today. A Pacific storm will bring low elevation rain and thunderstorms across southern California and heavy snow through the Sierra. Read More >

| The Clearing Index is an Air Quality/Smoke Dispersal Index used to regulate open burning and as input for other air quality decisions throughout Utah. The Clearing Index is defined as the Mixing Depth (depth of the mixed layer in 100s of feet above ground level) multiplied by the Transport Wind (average wind in the mixed layer in knots). Clearing Index values below 500 are considered poor ventilation and open burning is restricted under these conditions. Any Clearing Index values above 1000 are considered excellent ventilation and are referred to as 1000+. Data for the Clearing Index on these web pages are derived from several operational atmospheric computer models. The data will be reviewed and may be edited by NWS meteorologists before dissemination. | |
| An example calculation of the Clearing Index: | |
| Mixed Layer Depth = | 10000 feet |
| Transport Wind = | 8 knots |
| Clearing index = | (10000/100 feet) X 8 knots = 800 |
| Utah Smoke Management Program | |