Issued: 11pm on Monday, September 6th 2021
Technical Forecast Discussion
Short Term (Monday 9-6-2021 through Wednesday 9-8-2021)
Short term period is starting out with a departing 500H trough to the northeast with our weather pattern becoming zonal briefly tonight into Tuesday afternoon. As we move into Tuesday evening through Wednesday, another area of trough is expected to form over south-central Ontario where the surface low pressure also develops. This low pressure will have a cold front extending down from northwestern Michigan to north-central Illinois by Tuesday evening with severe thunderstorm forming due to CAPE values over 1000J/kg with main risk being of damaging winds out ahead of the cold front. As the front approaches our area late Wednesday morning into early afternoon hours, the severe weather threat nearly comes to end as we loose our upper level support due to broadening of the trough over most of eastern half of U.S. by late Wednesday. The surface front should clear our area by Wednesday afternoon with temperatures expected to be knocked down to typical mid-September levels.
Long Term (Thursday 9-9-2021 through Sunday 9-12-2021)
Long term period continues to have broad trough over eastern sections of U.S. through Thursday with trough departing eastward by early Friday, but general dip in jet stream still remains in place despite heights rising. On surface level, high pressure area will begin to settle over western Ohio Valley as our area remains under cool and crisp northwest flow and more of the same is expected for Friday with surface high now being centered directly over central Kentucky area. As the surface high moves eastward by Saturday and Sunday, air temperatures are expected to rise into lower 80’s once again under southwesterly flow once again. At this similar time, another 500H trough is expected to form directly over mid-west area by late Saturday, and eventually push quickly in to our area by Sunday. Weather conditions are mostly expected to stay on quite side during this long range period.