Why do the Freezing Level forecast and the Temperature forecast at mountain locations sometimes not match up?
A12. Multiple freezing levels sometimes develop over the mountains, and our meteorologists are typically forecasting the highest freezing level. To get multiple freezing levels, you must have an atmospheric “inversion”. An inversion is simply a super-stable layer of the atmosphere in which the temperature gets warmer, not colder, as you rise in elevation. Inversions can develop under several scenarios. The most common scenario is what we call a nocturnal inversion. This occurs when the temperature on the ground drops below freezing at night, even as the air temperature one thousand feet off the ground, or one thousand feet up a mountain slope, remains above freezing. If this is the reason for an inversion and you are below the forecast freezing level, the temperature at your location should rise above freezing in the afternoon. Inversions are also quite common in the winter months near the major passes in the Cascades when an upper ridge develops aloft and an east wind develops at the
Related Questions
- What if the actual temperature on a CPP event day is lower than the temperature forecast from the day before? Can SDG&E cancel the CPP event?
- Why do the Freezing Level forecast and the Temperature forecast at mountain locations sometimes not match up?
- What level of forecast accuracy is considered best practice or world class?
