(11:45AM Friday - 3/18/22) A storm system moving through the region today will bring a severe t'storm risk across Southern Illinois, through this evening.
Little to no change was needed with this update, as the previous forecast is on track.
A storm system moved from the Southern Plains last night, and will track through the mid-Mississippi Valley by this afternoon, and eventually into the Southern Great Lakes by Saturday morning. This storm system is expected to bring a severe t'storm risk to portions of the state and region today.
This Afternoon - This Evening, March 18th ~ Severe T'Storm Event:
The main risk for an isolated to sporadic (levels 1-2) severe t'storm risk will exist across Southern Illinois, through this evening. An initial round of rain and t'storms has been spreading across a large portion of the state this morning. As the main storm system moves through the region, a warm front has lifted northward through the southern half of the state this morning, putting the southern half of the state in the warm sector and in an environment favorable for some severe t'storm risk. Additional scattered showers and t'storms are developing from the area of low pressure on southward along an advancing cold front, across Southern Missouri and Northern Arkansas. This activity, along with further expected development, will then move northeastward across Southern Illinois, through early this evening. The environment that will be in place will feature low instability of 250-1,500J/KG, dew points in the mid to upper 50's good shear, good forcing, and good lapse rates of 6.5-8.5C. This environment will be supportive of upwards of an isolated to sporadic severe t'storm risk (levels 1-2) across Southern Illinois. Damaging winds, hail and an isolated tornado will be the severe weather threats.
Below is the severe t'storm forecast for this event.
-An isolated to sporadic (levels 1-2) severe t'storm threat across Southern Illinois, through this evening.