Issued: 5pm on Thursday, November 25th 2021
Technical Forecast Discussion
Short Term (Thursday 11-25-2021 through Saturday 11-27-2021)
Short term period is starting out with a weakening and departing upper level ridge starting to weaken as it gradually heads eastward into northeastern states through the day on Thursday. At the same time, there is an developing area of troughing over far northern midwest area which is expected to dive southeastward closer to our area. As this trough has been developing, it helped to generate a surface storm over eastern upstate parts of Michigan which is expected to move eastward throughout the day. A cold front is expected to be extending down through eastern parts of Michigan, central Indiana, and far southeastern Illinois area as of Thursday afternoon. Out ahead of the cold front, we have southerly flow which is brining moisture northward into our area and as of result, expect band of steady rain showers developing over Indiana very early Thursday morning which moves into Ohio and eventually clears out by evening hours for our region. Expect rainfall totals to be tenth to quarter of an inch for our area by end of this event. Moisture does not completely go away as more of it moves southeastward from Lake Michigan into our area later on Thursday night and with temperatures falling tonight, expect any scattered rain showers to changeover to snow showers as of result. Looking at the upper levels, the trough will start to enter over our area by Thursday evening and is expected to strengthen as it takes a neutral tilt some time after midnight Friday. As we progress through early Friday morning, this trough eventually take on a negative tilt as the main axis moves into western Pennsylvania. The trough tilts negative bit too late for main band rain to change to snow earlier which would have also lasted longer duration in our area if the process happens earlier, but nonetheless we will still see colder air settle in with scattered flurries and snow showers. I do have concern about any remaining wet roads becoming icy tonight as temperatures in our area is expected to dip few degrees below freezing so I would maintain caution if you are heading out for any black Friday shopping during early morning hours. I expected some isolated flurries to be in our area to start the day on Friday, but look for clouds to try to clear our somewhat later in the day as we have a surface high moving into western parts Ohio Valley region by this time. High pressure is expected to move eastward right over central appalachians region on Saturday which would allow clear conditions to hold firm in our area. While the main axis of the upper level low continues to deepen as it moves into northeastern parts of U.S., general troughing largely expected to remain over our area for Friday and Saturday so chilly weather remain in place for us. As we head into Saturday evening, there is another disturbance expected to form along great lakes region in response to another weak upper level trough which will have rather widespread area of precipitation with snow breaking out for much of southern Michigan, northern Ohio, and northeast Indiana area while rain showers further to the south. Our area in perticular is expected to stay dry for all day Saturday with moisture moving in early Sunday morning. Temperatures during this period will start out on warmer note with highs in lower 50’s out ahead of cold front on Thursday which then drops into mid 30’s for Friday before it rises back up into lower 40’s for Saturday under plenty of sunshine. Morning low temperatures will be in upper 20’s Thursday night which drops around 20°F, if not cooler, Friday night before rising again to upper 20’s into lower 30’s once again by Saturday night. Temperature anomalies during short term period will be in order of 5°F-8°F below normal.
Long Term (Sunday 11-28-2021 through Wednesday 12-1-2021)
Long term period resumes with a low pressure area eastward along great lakes region with precipitation moving through much of Michigan and Ohio during early hours of Sunday. This system will move eastward and weaken as it hits higher elevations of appalachians. As mentioned above, precipitation mainly looks to be in form of snow for much of lower Michigan into northern Ohio while we transition into rain for central Ohio area for duration of this event. Precipitation type for our area might actually start out as some brief snow due to temperatures initially being slight below freezing before we warm up and mainly switch over to rain showers early Sunday morning with scattered coverage as moisture does not fully extend further as far south into our area. Scattered precipitation will continue through the day on Sunday with precipitation changing back to snow late afternoon and evening before coming to an end just around midnight hour. While snowfall accumulation for lower Michigan and northern Ohio be around 1″-3″ inches, our area will only see dusting at best based on latest trends. In upper levels, there is another disturbance which dips into central Michigan during Sunday afternoon which likely brings more snow for them, but we remain dry as this new system will be too far to the north. Given that we are still few days out, there will some modeling changes, although the forecast mostly looks set. General troughing remains in our area for rest of Sunday into Monday with strong area of upper level ridge developing for all of western half of U.S. On surface level, another area of high pressure moves eastward along Tennessee valley so look for skies to clear out on Monday which then quickly skips eastward with time during late Monday. Interestingly, we might have an exact repeat of Saturday night into Sunday weather again from Monday night into Tuesday for about the same exact areas as well based on latest model trends. Light snowfall may breakout again for much of Michigan again Monday night and head into Ohio and Pennsylvania by Tuesday with rain showers to areas further to the south. We will know much more in detail about this system as we head closer in time as not all models agree on this solution. During late Tuesday into Wednesday period, upper level ridge will eventually try push eastward into our area, but geo-potential heights will likely be zonal for us as we are stuck between the trough and ridge. Our temperatures do look to warm up slightly during these two days with dry conditions in place. Temperatures during the long term period will be start out in lower 40’s for highs for Sunday and Monday which only rise into middle 40’s for Tuesday and Wednesday with morning lows dropping into upper 20’s to lower 30’s range during this period. Temperature anomalies during this forecast period will be about 2°F-4°F below normal for this time of the year.
