Long range video forecast:
EVENING – TONIGHT: Rain and t’storms will continue across zone 6/7 as a cold front approaches from the west.
Strong winds are already streaming in across the region. At 500 mb winds are coming in out of the southwest at 95-110 mph.
This while winds lower in the atmosphere at 850 mb are coming in out of the south and southwest at 55-70 mph.
With these kind of strong winds in place it will work two-fold for severe weather. The first being is that with increasing winds with height, high amounts of speed shear will be present in the environment and this is a key ingredient for severe storms. The other things is, once thunderstorms do develop and rise through the environment they will tap into those strong winds and could bring them to the surface, thus enhancing the damaging wind threat this afternoon/evening. For that reason a Tornado Watch is in place until 7 PM CST across southern Illinois.
By 5-6 PM this evening will be moving across central and eastern portions of the zones into Indiana as the front moves to the east too. It appears only a few isolated to widely scattered areas of rain/storms will be ongoing in western Illinois.
Through the evening the front will push eastward, as it does most of the rain and storms will exit Illinois to the east by 10-11 PM.
The best threat for severe weather looks to be from the I-70 corridor southward this evening.
New rainfall totals of .10-.30” will be more common across zones 6/7. However, areas where the heaviest storms move through local amounts of .75-1” can’t be ruled out.
Temperatures will continue to rise today. Eventually topping out in the mid 50’s north to mid 60 to near 70.
Overnight the initial front will pass off to the east. However, with some low-level moisture hanging around a few isolated rain showers or drizzle can’t be ruled out.
Lows overnight look to fall near freezing north to the lower 40’s south.
WEDNESDAY: Mostly cloudy skies will remain in place across the forecast zones. However, by late morning and early afternoon snow showers look to move across Illinois. This will be aided by a piece of upper level energy moving across the region.
Periods of snow will remains possible across zones 6/7 through the evening hours Wednesday. However, as the upper level energy moves out of the area snow shower chances look come to an end around 9-10 PM
Highs across the region will be in the mid 30’s north to low 40’s south.
Regarding any snowfall accumulations I am currently not anticipating any major accumulations with only a coating to .20” possible in scattered areas. The latest GFS shows that possibility. However, I don’t think they will be as widespread as the model suggests.
Overnight Wednesday into Thursday an area of high pressure will begin to move into the region. This will help start to clear out overnight.
Lows will be in the 20’s.
THURSDAY – FRIDAY: High pressure looks to remain in control to end the week. Mostly sunny conditions look to be in place across the region Thursday through mid-afternoon Friday.
Highs to end the week will be in the low 30’s to the low 40’s.