Today's Thunderstorm Potential

Editors Note: Post has been updated to include correct SPC categorization of thunderstorm risk, which was erroneously called "severe" in the original.


Yesterday evening, the northern portion of the state won the thunderstorm lottery with strong storms developing over the West Desert and Great Salt Lake and moving across the Northern Wasatch Front, Box Elder County, and Cache County.

Strong wind gusts were reported at a remote observing site east of Snowville (78 mph) and the Logan airport (61 mph).  Lightning data shows numerous cloud-to-ground strikes across that area, but none south of Ogden or over the Salt Lake Valley.  

Source: lightningmaps.org

The National Weather Service watches, warnings, and advisories map is lit up statewide today.

Source: NWS

Issues of concern for today include flooding and flash flooding, high winds, and severe thunderstorms.  The Storm Prediction Center has upped our severe thunderstorm risk from severe marginal to slight.

Source: SPC

The weather situation this morning shows that we are currently sandwiched between two precipitation bands, one to our west that is near a surface trough (not shown) and the other to our east.

During the course of the day today, the surface trough is expected to progress slowly into northwest Utah, while the precipitation band to our east remains roughly between Salt Lake and Vernal.  The big question mark for our weather is whether or not something will bubble up in the intermediate dry slot.  The HRRR shows this as a possibility.  Note the strong simulated reflectivity cells between the two precipitation bands early this afternoon.  

However, these types of storms are very chaotic and we're just going to have to see how this plays out.  

This evening the surface trough will approach Salt Lake, and should be accompanied by showers and thunderstorms.  It's not the usual rapidly moving cold front.  It sort of stalls over northern Utah as the upper-level trough moves through and eventually the so-called "wrap around precipitation" moves across the state.  Tonight through tomorrow night looks quite unsettled and the mountains will get snow.  I need to run to class, however, so discussion of that will need to wait until tomorrow.