The products on this page support DCOTSS forecasting and flight planning activities. GFS tropopause maps are updated every 6 hours, GridRad and GOES overshoot history and trajectory forecast maps are updated every hour (with trajectories recalculated every 6 hours using the latest GFS winds – updates occur at 6 AM/PM and 12 AM/PM Central). Updated products are usually posted here by 30 minutes past the hour, with longer delays possible during the 6-hour updates.
Descriptions of the trajectory forecast products:
Day – overshoot trajectory particles colored by day & time when they occurred. Days are 12 UTC – 12 UTC, centered on and labeled by the day at 00 UTC (the approximate time when overshooting is climatologically most frequent).
Age – overshoot trajectory particles colored by the time elapsed between overshoot occurrence and the forecast time. Trajectories are only calculated for up to 3 days past overshoot occurrence.
Source – overshoot trajectory particles colored by source region. There are four pre-defined source regions: the Sierra Madre Occidental (102-112ºW, 14-31ºN), the US Great Plains (93-104ºW, 30-50ºN), the Southwest US (104-120ºW, 31-40ºN), and the Southeast US (79-93ºW, 24-36ºN). Overshoots occurring outside of these defined regions are colored white.
Potential Temperature – overshoot trajectory particles colored by their potential temperature. Trajectory calculations for overshoot forecasts are isentropic, so the colors never change past initialization.
Temperature – overshoot trajectory particles colored by their current temperature. Particles are plotted such that the coldest are on top.
Altitude – overshoot trajectory particle altitudes (in kft for consistency with pilot guidance for flight planning). These can change after initialization, depending on the 3D structure of isentropes (surfaces of constant potential temperature).
Relative Altitude – overshoot trajectory particle altitudes relative to the local GFS lapse-rate tropopause. These can also change after initialization and depend on the time-evolving tropopause altitudes along the path of the particles and the altitudes of isentropes. These are useful guidance to ensure overshoot material remains in the stratosphere after occurrence.
Multi-panel – overshoot trajectory particle counts for multiple potential temperature and altitude layers. These indicate the density of overshoot material and include contours for tropopause potential temperature or altitude.
North America NCEP GFS forecast maps – 1024 x 768 pixel resolution
