Using NUCAPS and ProbSevere LightningCast to anticipate a line of showers
A weak line of showers moved through southern Wisconsin late in the afternoon of 10 June 2022, as depicted in the 2001 UTC toggle above of NEXRAD Composite Reflectivity and GOES-16 Day Cloud Phase Distinction RGB. What satellite-based products could be used to anticipate that line?
NOAA-20 orbits over the Midwestern United States on 10 June (shown here, from this site) were configured such that NUCAPS profiles over Wisconsin were derived from two consecutive passes. The toggle below shows derived Total Precipitable Water at ca. 1730 and 1930 UTC. Dry air over northeastern Wisconsin is abutted by greater values of total precipitable water over the southern part of the state.
Data from NUCAPS profiles can also be used to compute various stability indices, including the Total Totals index, which is shown below from the two passes. Note in particular the gradient in the index over southern Wisconsin at 1930 UTC: a corridor of instability is present, and it is focused in that location mostly because of dryer air to the northeast (click here to view 850-mb Mixing Ratio from gridded NUCAPS at 1730 and 1930 UTC). In addition, diagnosed mid-level Lapse Rates (in this case, 700-500 mb) at 1930 UTC (shown below) show values between 7 and 8 oC/km. (Note to AWIPS Users: Gridded NUCAPS Total Totals index values can be accessed via the Product Browser, under ‘Grids’)
ProbSevere LightningCast (link) is a forecast aid created to diagnose (from ABI imagery) the probability that a GLM Lightning observation will occur in the next 60 minutes. It can also alert a forecaster to developing convection, because the satellite signatures that suggest lightning might occur in the next 60 minutes often occur before radar observations of convection. The animation below shows LightningCast at 15-minute time steps, from 1800 to 2000 UTC on 10 June. Note how LightningCast keys on the developing line of cumulus long before showers develop (and more than 30 minutes before lightning occurs!)
The animation below shows GOES-16 Day Cloud Phase Distinction overlain with Geostationary Lightning Mapper (GLM) Minimum Flash Area (MFA) observations, from 2001 – 2316 UTC. Consider the smallest MFA values (in yellow) to represent vigorous, new updrafts. Larger MFA (green) are more likely in the anvil.
NUCAPS and ProbSevere LightningCast added to Situational Awareness for this event.
Some imagery in this Blog Post was created using the NOAA/TOWR-S AWIPS Cloud Instance. Thank you!