Technical Discussion

Synopsis

 

Upper level low will slowly slide eastward from the great lakes and anchor over the Ohio valley sometime Friday evening. Low will become closed off and will deepen over the weekend. Unsettled conditions will last at least until early next week.

 

Short Term

 

A strong upper level low will detach itself form the jet stream and move southeastward on Thursday, bringing showers and a possible thunderstorm to the area. It should be noted that showers are more likely in the eastern portions of the forecast area. Broad ridging will allow for the system to nearly stall over the Ohio valley sometime on Friday. The low will become closed off and will continue to deepen and spin up moisture from the atlantic. Unsettled weather should be expected both Thrusday and Friday with this system. Temperatures on Thursday will be at or slightly above normal, with some cooling on Friday in western zones due to the passage of a cold front and cooler air being brought in by the upper level low.

 

Long Term

 

As the upper level system continues to spin into Friday night and Saturday, swaths of heavy rain will move north across the region. Model guidance does not seem to have a good handle on exactly where and when these heavy bands will hit however. Latest WRF (0Z) has heavy bands moving through central zones early Saturday and then seperate bands moving through extreme eastern and western zones later in the day. GFS guidance likes move the rain through earlier, ie. late in the day Friday. Regardless, there will be bands of heavy rain moving through Friday night as the system deepens and becomes stagnant. This will keep a chance of rain through at least Tuesday, with conditions becoming better for the second half of next week as the cutoff slowly moves out.