Saint Louis University-CIPS has recently developed experimental analog-based severe probability guidance, which is available here: http://www.eas.slu.edu/CIPS/SVRprob/SVRprob.php There is a link at the bottom of the page that provides a brief technical explanation of the guidance, and we’ll be adding another link soon that provides a video tutorial of how to use the product. In the meantime, here are a couple pointers on how to use it and things to remember: This is different from the current CIPS analog system. The current system is frequency based (i.e., how many of the top analogs are showing severe). This new guidance's probabilities are produced via a logistic regression model that is trained on the top 100 matching analogs and their related SPC severe reports (or lack thereof). Yes, we are aware of the numerous issues that come with using storm reports for building the guidance and especially using filtered reports for verifying the guidance. A verification page is being developed and should be available soon. The Day 1-8 guidance maps can be selected at the bottom of the map. The calendar date listed below each “Day #” is the valid date (always at 0000 UTC). Clicking on the calendar date will bring up a page that shows all the guidance that is valid on that date. Once a valid date has passed, the filtered SPC reports will be displayed along the bottom row. You can access the last 8 forecast dates by clicking on the dates along the top of the map. This allows users to view how the guidance performed over the last 8 days worth of events. We had a network outage two weekends ago, so some of the maps for events over the last 8 days may not be available. The readout on the right-hand side is based on a selected point on the map, which is done by clicking on the map. Each item in the readout is a clickable link that will bring up a short explanation of what the item is. The probability seen in the readout corresponds to the “raw” probability, so the values may not always correspond to the smoothed contours in the map. In the top right of the map, users can switch between the smoothed contours and the pixel view, which shows the raw probability by grid point. The guidance is always based on the GEFS mean forecast initialized at 0000 UTC and is always valid at 0000 UTC on the valid date. We are looking into using individual members rather than the mean. The original purpose of the product is to provide probabilistic guidance in the extended forecast period (3 or 4-8 days out). The guidance is provided in the short term forecast period in order to see trends and for verification. Given the GEFS is a relatively courser model compared to hi-res models available in the short-term (HRRR, NAM 3km, etc.), and the guidance uses the 0000 UTC initialization forecast that’s valid 24 hours later, the guidance may not be able to pick up on mesoscale features that may be significant drivers for severe weather in the Day 1 range. The point of the guidance is to pick up on the synoptic pattern in the extended range, not mesoscale features in the short range. THE GUIDANCE IS EXPERIMENTAL. There are still things we need to check and adjust if necessary. The “All Severe” probability is what we originally started producing a year ago. The individual hazards (hail, wind, tornado) are recent additions that also need to be evaluated thoroughly. THE PROBABILITY OF SEVERE IS WITHIN 110 KM OF A GRID POINT. SPC’s probabilistic outlooks are the probability of severe within 40 km of a grid point. Therefore, the products are not directly comparable. We have talked and worked with SPC on the guidance regarding either producing the CIPS guidance on a 40 km grid or figure out how/if the CIPS guidance probability thresholds relate to SPC probability thresholds in order to make it more useful to SPC forecasters. Sorry for the long post. Feel free to ask any questions below.