After almost two weeks of cloudy, dreary days the sunshine Sunday was well deserved. Combine that with a gusty west wind and it helped to give an almost Spring-like feel to the afternoon. High temperatures across southern Wisconsin and northern Illinois reached the upper 40s, with a few locations topping out in the low to mid 50s. Chicago, Milwaukee and Madison all broke record highs Sunday afternoon!
Unfortunately the sunny skies from Sunday are only temporary as clouds will be back on the move overnight, into Monday morning. An area of low pressure developing to the west Sunday evening will move east during the day Monday, passing south of the Stateline Monday night and Tuesday. Northeast winds will strengthen a bit during the day Monday but shouldn’t be overly gusty. Despite the northeast breeze, however, temperatures will still warm above average into the upper 30s and low 40s. Moisture moving in from the southwest will likely allow areas of drizzle to develop late in the evening and overnight, but as temperatures cool below freezing, freezing drizzle could also occur into Tuesday morning. This may cause some slick spots for the commute during the morning.
The overall jet stream pattern turns active across much of the country with the southern branch of the jet stream remaining a bit more active than the northern branch. This will help drive a few areas of low pressure across the southern Plains and southern States Monday, Tuesday and Wednesday before shifting into the southeast and up the East coast later this week. High pressure to the north will likely block a couple of the low pressure systems from lifting too far north, but the high will begin to lose its grip Wednesday and Wednesday evening. While the main low pressure system will remain to the south, an extension of the low (inverted surface trough) may extend north into northern Illinois. This combined with an upper level disturbance could trigger a few snow showers Wednesday night into Thursday morning. If snow were to develop, minor accumulations would be possible.