Issued: 5pm on Thursday, October 5th 2023
Technical Forecast Discussion
Short-Term (Thursday PM 10/5/2023 through Sunday 10/8/2023):
With a strong longwave trough in the upper levels closing in on the forecast region, its associated surface low pressure is expected to make its way to the north of the Great Lakes region by Friday morning into the afternoon. This low-pressure system is anticipated to drive a strong cold front through the region sometime tonight into the early morning hours of tomorrow. The cold front will bring with it showers, some more heavy, and the potential for a few rumbles of thunder on Friday.
This surface low is well into the mature stages of its life cycle as it has formed an occlusion already as the upper-level low begins to close off and the low will start to fill in. This is indicated by strong PVA in the upper levels and the overlap of surface low-pressure and the 500 mb low. As the trough gains a very definitive negative tilt, we expect this low-pressure system to begin to dissipate likely by Saturday morning.
Long-Term (Monday 10/9/2023 through Wednesday 10/11/2023):
As the upper-level jet remains parked overhead, things at the surface are currently expected to clear up for the most part. Clouds are expected to clear out beginning roughly Tuesday afternoon. Probabilities of precipitation also drop off sharply after the frontal passage, so after clouds begin to clear out, expect nicer conditions. This nicer weather will come as the jet supports a surface high-pressure system with sinking air and NVA around the right exit of that jet streak with a region of speed divergence. Temperatures are expected to be below the seasonal average, according to the Climate Prediction Center with daytime highs barely reaching into the 60s except for Wednesday, hopefully getting into the mid-60s, but for any fall lovers, I’m sure that won’t be a problem.
Thursday PM – Saturday: Cloudy with chances for rain Thursday PM, increasing with chances for thunderstorms on Friday, decreasing Saturday.
Sunday – Monday: Cloudy, below-average temperatures.
Tuesday – Wednesday: Clouds beginning to clear out, temperatures warming slightly reaching the mid-60s by Wednesday.