Wednesday, September 23, 2015
Fall is Here! (Sort of)
A surface low pressure system over Nebraska and South Dakota is expected to weaken as it moves toward a relatively stronger high pressure center over western Ontario. This should keep any precipitation well north of Madison on Thursday. In addition, an 850mb high centered over the eastern Great Lakes looks to remain stationary over the next two days, providing Wisconsin with the sustained warm temperatures we are likely to experience at the surface.
Convergence of 850mb geostrophic wind over northern Wisconsin on Monday could force a tighter temperature gradient and produce a thermally direct circulation over the northern half of the state and into Ontario. The cold air forced downward is likely to result in a (somewhat weak) cold front at the surface, leading to slightly cooler temperatures in Madison on Tuesday.