Pockets of heavy rain will be possible Early Wednesday with scattered showers and thunderstorms continuing through Thursday.

THE FORECAST:

Today and Tonight: Widespread, heavy rain will move across the region Early Wednesday. Embedded thunderstorms could produce downpours and some localized street flooding will be possible. An inch or two of rain could result from the heaviest storms. Steady rain is expected to break off around lunchtime. With cloud cover and areas of rain, temperatures should not climb above the low 70s. Winds will be easterly at 5-10mph. Scattered activity will continue overnight with a low temperature in the low 60s.   

Up Next: A very similar forecast will be carried into Thursday with scattered showers and thunderstorms and highs in the low 70s. By Thursday Night, with most of the storm system over, a two day total of 1-2” will be possible. There is some uncertainty with the Friday to Sunday time period. Right now, the three day stretch is forecast to feature partly sunny skies and highs in the upper 70s. Some pop-up showers and thunderstorms may need to be added as we get closer.  

THE SCIENCE:

Forecast Discussion: On Wednesday, a more pronounced shortwave sliding through the sub-tropical jet stream will introduce waves of positive vorticity advection to the region. With dew points in the low 60s and some moisture up into the mid-levels of the atmosphere per relative humidity charts, the upper energy should be able to stir up a few batches of showers and thunderstorms. While it is a little early for specific timing, agreement amongst models would suggest two waves—one Wednesday Morning and another Late Wednesday/Early Thursday. Scattered action will remain possible through Thursday Night though. The parameters for severe weather continue to look unimpressive. By Thursday Afternoon, the axis of that shortwave trough should be east effectively ending uplift and the chance for precipitation in the local area. Because of the periodic showers and thicker cloud deck, temperatures should be held in check, in the low 70s. Forecast models are not in good agreement as to what happens next. At this time, a dry forecast has been issued for Friday through Sunday though that will be highly dependent on the behavior of a deep cutoff low in the Southwest. The GFS model holds the upper energy associated with that rain to the west while the ECMWF brings a few lobes of vorticity through the local area. Should this be the case, an ongoing return flow at the surface would allow enough moisture for scattered showers and thunderstorms Friday to Sunday. Uncertainty increases with greater distance west from I-55. Stay tuned as new information becomes available!

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