Monday, August 15, 2011

Nighttime Thunderstorms

I'm feeling a bit groggy today after being roused shortly after midnight by a great round of thunderboomers.
KMTX Radar Reflectivity at 0600 UTC (0000 MDT) 15 Aug 2011.
Source: NCAR/RAL
The frequency of thunderstorms in Utah is highest at around 4–8 PM local time (see Wallace 1975, Fig. 2), but once shouldn't interpret this peak to mean that we can't have thunderstorms at night.  Thunderstorm triggering and maintenance mechanisms include far more than just surface heating and in some parts of the world, such as the upper midwest (i.e., Iowa, Missouri, and environs) the frequency of thunderstorms is actually greatest at night.

Issues related to the diurnal cycle of convection and precipitation are currently a "hot" topic in the atmospheric sciences literature.  For example, the University of Utah's own Weixin Xu and Ed Zipser have a recent publication examining diurnal modulations in convection and precipitation over and east of the Tibetan Plateau (Xu and Zipser 2011).


  1. I would be willing to bet that portions of northwestern Utah (especially in the immediate vicinity of the GSL) have a nocturnal maximum in thunderstorm activity. Has anyone done a more localized analysis? For example, lightning frequency maps for Utah by hour of the day would be very interesting. I am guessing that one may find a lightning maximum between about 2000 and 0200 local time in much of the greater Salt Lake Basin and northern/central Wasatch Front.

  2. That would be a very interesting study and would be quite feasible with current lightning data. The Wallace (1975) paper is based solely on surface observing stations.