U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 230052 
Storm Prediction Center ac 230051 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0651 PM CST Tue Jan 22 2019 

Valid 230100z - 231200z 

..no thunderstorm areas forecast... 

thunderstorm potential will remain low across the United States 
through tonight. 

..01z update... 

The Prospect for lightning within convection remains low tonight. 
00z soundings ahead of a progressive trough remain strongly capped, 
or weakly buoyant this evening. Large-scale forcing for ascent 
should encourage mostly shallow elevated convection, especially 
across portions of the lower-mid MS valley region, and el 
temperatures will likely remain a bit too warm to support a 
meaningful threat for lightning. Probability for thunderstorms 
remains less than 10%. 

.Darrow.. 01/23/2019 


Mesoscale Discussion

acus11 kwns 230001 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 230000 

Mesoscale discussion 0045 
National Weather Service Storm Prediction Center Norman OK 
0600 PM CST Tue Jan 22 2019 

Areas affected...portions of northern in...Southern Lower Michigan...and 
far northwestern Ohio 

Concerning...freezing rain 

Valid 230000z - 230600z 

Summary...generally light freezing rain should continue through much 
of the evening, with rates up to 0.05 inch per hour. 

Discussion...strong warm air advection is occurring with a 40-60 kt 
southwesterly low-level jet from the mid MS valley into the lower 
Great Lakes region this evening. Related isentropic ascent atop a 
shallow sub-freezing layer near the surface is contributing to light 
precipitation in a 100-125 mile wide zone from eastern Illinois into 
northern in, southern lower mi, and far northwestern Ohio. Surface 
observations over the past several hours indicate light freezing 
rain has been the dominant precipitation type so far across this 
region, as a shallow above freezing layer generally between 850-800 
mb per rap forecast soundings melts frozen hydrometeors aloft. This 
light freezing rain is expected to persist for at least a couple 
more hours as the 0c isotherm at 850 mb should only gradually shift 
northward across Southern Lower Michigan through 06z. Ice accretion rates 
up to 0.05 inch per hour have already been observed at several 
sites, and this trend should continue for several more hours. 
Eventually, gradual warming at low levels will likely result in a 
transition to rain as surface temperatures slowly increase above 
freezing from south to north. 

.Gleason.. 01/23/2019 

..please see www.Spc.NOAA.Gov for graphic product... 


Latitude...Lon 41118663 41368745 41678744 41718704 41958659 42298632 
42438548 42718415 42988302 43018248 42618243 42318296 
42058310 41628327 41268391 41188496 41118663