The heat and humidity will build back into the forecast areas today. While this may allow for a few isolated areas of rain or a couple t’storms to develop across the forecast zones this afternoon, most places will be dry as we remain under the influence of the upper-level ridge.
The big stories today and tomorrow will be the impressive heat that will be in place. Heat indexes this afternoon will be in the 90’s to near 100° in places. Monday afternoon heat indexes will range from 95-105° in many places!
Monday evening into early Tuesday a cold front will progress southward across the forecast zones. Scattered areas of rain and storms will develop Monday afternoon along the front and push southward across the forecast zones. I do think a few storms could be on the strong to severe side Monday afternoon and into the evening hours. Main threats would be gusty winds and some hail.
We will be watching Wednesday closely as the environment looks very conducive for a severe MCS or possibly derecho type event. With strong upper-level winds, impressive areas of upper-level energy/vorticity, afternoon instability, and a warm front in place, these will all provide the ingredients needed for at least a damaging wind threat Wednesday afternoon into the overnight. We will be watching the progression of this forecast carefully and will be fine-tuning it this week.
A great way to see the evolution/upscale growth into a MCS or Derecho is by looking at precipitation forecast. As the storm cluster or line grows, the precipitation field will expand north and south the farther eastward you go. This can be seen in several of the overnight forecast model runs.
Heavy rainfall will be possible in places this week under the area of storms. The latest GFS shows areas of 2.5-3.5” through Thursday morning. With the amount of moisture available this week, locally higher amounts will be possible, we will fine-tune rainfall amounts as we get closer to the forecast period.