CAPE GIRARDEAU, MO (KFVS) - A growing area of high pressure aloft combined with very humid southerly flow at the surface, will likely result in the most oppressive weather of the season so far.
High pressure aloft tends to put a 'lid' of warm air over the atmosphere, making it very difficult for cooling clouds and showers to develops.
Actual air temperatures by Sunday afternoon look to peak in the low to mid 90's, but combined with increasing humidity levels will likely result in heat index numbers of 100 to 105.
By Monday afternoon actual high temperatures may reach 95° to 100°, but with heat indices of up to 110 to 115. Official heat advisories or heat warnings will likely be needed.
Moderating temperatures along with a better chance of thunderstorms should develop by the middle of the week.