The Intermountain Precipitation Experiment

4.2 Forecast Products and Dissemination  

A variety of forecast products, described in the table below, will be prepared by the forecast team for daily meetings and forecast verification. These products have been selected based on program needs and the desire to limit as much as possible the ambiguous validation of forecasts. Forecast products will be archived via a world wide web page and available over the internet. The forecast team will present their forecasts at the 11 MST briefing that will be attended by the Operations Coordination Team and other interested scientists.

IPEX Forecast Entry

4.3 Forecast Comments

Guidance for forecasting lake-effect snowstorms can be derived from the recent paper by Steenburgh et al. (1999). Additional information concerning lake-effect of the Great Salt Lake is provided in Carpenter (1993) and Onton (1999). According to Steenburgh et al. (1999), lake-effect precipitaiton is most common overnight and in the early morning hours. Therefore, lake-effect IOPs will likely occur overnight, with operations ceasing in the early afternoon.

Forecasting orographic precipitation is covered by Dunn (1983).

Guidance for forecasting postfrontal lightning associated with lake-effect or orographic precipitation can be found in Schultz (1999). Schultz (1999) found that lake-effect snowstorms are more likely to produce lightning when the surface temperature is greater than 2C. Similar values of 700-hPa temperature, surface-to-700-hPa temperature difference, and lifted index are -10.5C, 13.7C, and 1C, respectively. Dewpoint depression and convective available potential energy are not useful in forecasting postfrontal lightning. 4.4 Nowcaster Responsibilities