Tuesday Night Outlook
Text From The RACES Tuesday Night Net:
Springs attempt to return to the area was crushed this afternoon as a back-door cold front swept across the area. However, we should make a slow recovery as the week progresses. Highs will remain in the mid- to upper 40’s through Thursday. Friday will warm into the mid-50’s, with Saturday reaching the lower 60’s and Sunday seeing highs in the lower 70’s. High temperatures for the beginning of next week will range from the mid- to upper 60’s.
We will see a chance of showers late Wednesday afternoon into Wednesday evening due to an upper level disturbance moving across the area. Otherwise, skies will remain partly to mostly cloudy, clearing to mostly sunny for Friday and Saturday, then returning to partly cloudy on Sunday into the beginning of next week.
Detailed Forecast Discussion:
Spring made a valiant effort to return to the area today with south and west portions of the forecast area reaching into the 70’s. However a cold front, enhanced by the lake and associated with the mid-level trough moving east across Lake Michigan at mid-afternoon, has cutoff the warm air at the pass.
A clearing trend will continue through the southern portion of the forecast area late this afternoon into early this evening. The models appear to have reached the proper solution of developing a closed low over the western Great Lakes tonight, as infrared and water-vapor imagery are starting to show the beginnings of rotation over the UP of Michigan.
This disturbance will only gradually sink to southern lower Michigan by 7:00 AM Wednesday, as it’s progress is delayed by the upper low currently over the southern Plains moving east across the Ozarks to the lower Mississippi Valley. As this upper low continues east during Wednesday morning, it will allow the Great Lakes circulation to then progress farther south, reaching central Indiana by late Wednesday afternoon. This mid-level circulation will tap into the moisture being advected westward across southern Quebec by the large Atlantic storm off of the northeast coast of the US.
During the day Wednesday, low level flow will be anticyclonic as a surface ridge builds across western Ontario and the upper Midwest, with flow transitioning to cyclonic with the mid-level low over the region. Deeper moisture will be in place Wednesday, so we expect cloudy to mostly cloudy skies. NAM and the GFS models all show a 30-40% chance of precipitation for late Wednesday afternoon into early Wednesday evening. Given the lack of upper vertical velocity and lapse rates not conducive to strong diurnal development, the feel is that chances of precipitation should be lowered to scattered rain showers.
As the Atlantic storm moves off to the east, high pressure continues to build in across eastern Canada and the Great Lakes. The maintains the cool northeast low-level flow across the region, with enhanced cooling by the cold lake waters on Thursday. Warm air advection spreads from the Plains across the Mississippi Valley on Thursday night and Friday as an upper ridge builds east across the Plains, but with the surface ridge still over the upper Great Lakes Friday evening, temperatures near the lake will remain cool.
A shortwave currently moving ashore in northern California and the Pacific Northwest is forecast to lift across the northern Rockies and the northern High Plains Thursday and early Friday, as flow is still blocked by the Atlantic storm. A strong upper low south of the Aleutians is forecast to reach the northern California coast by Friday morning, then gradually move to the central Rockies by Saturday night, lifting into the upper Midwest by Sunday night. The best chances for thunderstorms with this approaching system will by from late Sunday through Monday as a cold front gradually pushes east across the forecast area.
