Via @NWSIndianapolis… Temperatures will warm through the weekend, with highs today in the 50s to around 60, and Sunday around 60 to the mid 60s. Lows will generally be around 40 to around 50. Expect mostly cloudy skies today, with more breaks of sunshine on Sunday.
The day begins with stubborn stratus clouds stuck over the entire region. The stratus is stuck under a strong subsidence inversion trapping low level moisture near the surface. The low sun angle this time of year struggles to heat the boundary layer enough to break the inversion and lift the clouds out of the area. Due to such a saturated environment with heavy cloud cover, the past 24 hours have only seen a diurnal temperature range of around 3 degrees in many spots, with temperatures stuck in the upper 40s. This same pattern continues through the rest of the morning hours today.
Short term guidance does indicate the surface high and associated ridging pushing north and east throughout the day, with winds becoming southerly to southwesterly through the column. Increasing winds and warm air advection may work to erode some of the low clouds, especially across portions of Southern and Western Indiana.
A significant change is on the horizon for the long term portion of the forecast. Well above normal temperatures will persist into the early portion of the work week, with highs in the 60s Sunday into Tuesday as upper level ridging and broad southerly/southwesterly flow through the depth of the troposphere persists ahead of a large incoming low pressure system. The highest likelihood of rainfall will come late Monday into early Tuesday as the primary warm conveyor belt associated with the potent, wrapped-up low pushes through the region. That said, rainfall amounts may be limited by active occlusion occurring with the low, which could act to split more significant moisture between the deformation zone near and northwest of the low, which will pass to our northwest, and the low level WCB, which may be maximized more to our south and east.
In the wake of this first system, a second upper level low is likely to drop into the Midwest and reinforce the first, potentially leading to rapid cyclogenesis somewhere in the region Wednesday into Thursday, though confidence is low on exact placement and timing of this secondary cyclogenesis.
This secondary system will require reintroduction of precipitation chances after a brief break Tuesday night, with high PoPs, especially Wednesday night into Thursday as the surface low pivots around the larger upper level low. Temperature profiles may be borderline, but there is a non-zero chance for the first snowflakes of the season to fly Wednesday night into early Thursday, perhaps aided by much above normal lake temperatures which could add lake enhancement to the equation. Again, between the timing and placement of this second system, uncertainties with respect to the strength of the cold intrusion into the area, and this being a significantly unusual evolution of a synoptic system in this region, confidence is low at this time in details, but suffice to say, the latter part of this week will turn sharply cooler, windier, and wetter than the early portion of the week, and than much of the young cool season has been thus far.
Never miss me! Subscribe for free. My Huge Radar has real-time weather tracking, current temperatures, and severe weather watches and warnings. Get detailed Indiana conditions by clicking here. Click here to see my central Indiana 7-Day Forecast. Follow these links to get my forecasts for Lafayette, Muncie, Hendricks County, and Hamilton County. Need a second opinion? Click here for central Indiana National Weather Service forecasts. (Some charts via WeatherBELL.)
Leave a Reply