With higher intensity storms from the changing seasons, there are more storms to process through MetStorm™. One of the more recent storms to occur in Louisville, KY provides a great opportunity to showcase one of the analytics MetStorm™ generates – the mass curve plot.

But first, the Louisville, Kentucky storm set up and background.

This storm was initiated by a passing cold front which extended from eastern Canada through the Central Plains. As it was moving through the Ohio River Valley the cold front transitioned to a stationary front leading to training thunderstorms and widespread flooding. The following surface analysis map is from the Weather Prediction Center’s Archive page. One feature in particular to point out is the squall line analyzed over Kentucky, which happens to coincide with where the highest precipitation totals were measured.


It should also be noted that this storm set new records for Louisville and Lexington. The previous record for maximum daily precipitation was 4.08″ recorded in 1970 at Louisville, KY and 3.21 recorded in 1908 at Lexington, KY. The new maximum daily precipitation is now 5.64″ and 5.17″ for Louisville and Lexington, respectively, recorded on April 3, 2015.

And now, the moment you have been waiting for – MetStorm’s™ mass curve plot!


This plot represents both the incremental and accumulated rainfall for the storm’s maximum grid cell. The timing of the storm is determined from a combination of hourly station data from a plethora of sources and radar estimated rainfall from Weather Decision Technologies Polarimetric Radar Identification System Quantitative Precipitation Estimates, or POLARIS QPE (These sources and others will be discussed in future blog posts!). The left y-axis displays the incremental rainfall amounts, where the right y-axis displays the accumulated rainfall amounts. Both variables are displayed in inches (inner scale) and millimeters (outer scale). The x-axis shows the precipitation amounts through time in UTC. Currently the time scale for this plot is hourly; however, in the near future this will be changing to a 5-minute time scale resolution.

In the recent Louisville, KY storm, it is evident by the mass curve that there were two distinct periods of heavy precipitation. The first pulse of precipitation of just over 2 inches occurred around 6Z on the 3rd, where the second pulse of just over 1.5 inches occurred around 21Z on the 3rd.

This plot is a useful tool that shows in multiple ways the timing of precipitation for storms. The applications for this product vary widely from emergency management to hydrologic modeling validation and calibration to flood responses, forensic cases, insurance claims, situational awareness, and many more.

If you are interested in this product, or any other product from our MetStorm™ Precipitation Analysis tool, please contact us at info@metstat.com or through our contacts page at http://metstat.com/contact-us/

We hope you enjoyed today’s blog post! Come back soon for more exciting information and examples of MetStorm™!

-MetStat Team