Issued: 8pm on Sunday, January 5th 2025
Technical Forecast Discussion
Short-term Forecast (Sunday 01/05/2025 through Tuesday 01/07/2024):
A low pressure system currently undergoing early-stage occlusion has arrived in the south-central United States, with a warm front current swinging upwards into the lower Tennessee Valley. Ahead of this warm front is a large swath of winter weather, separated by a warm nose of above-freezing temperatures around 800 mb behind the 540 line, which will slowly push into central Ohio throughout the night. This warm-air advection-induced precipitation will remain more centralized to the lower Ohio region due to low-level dry air blocking further north. As this low pressure system continues eastward, heavier bands of snow will arrive in the southern to southeastern Ohio region due to a surge in low-level moisture, with the heaviest snowfall occurring around 03Z (11 PM Sun). Snowflakes will be large and aggregated, as evidenced by a maximizing of omega in the 490-540 mb dendritic growth zone, and as such, snowfall rates > 1″ per hour could be possible. Around 06Z (2 AM Sun), possible encroachment by the 800 mb warm nose could result in surface sleet rather than snow as the low pressure system undergoes cyclolysis and snow bands weaken. As the decaying low core continues eastward as pulled by the upper-level jetstreak, widespread snow will disperse to more scattered and localized banding through 11Z (7 AM Sun). Then, backend light snow showers will persist through 00Z Tuesday (8 PM Mon), possibly adding another half inch to an inch of snowfall. Total snow accumulations from this system could range from 6-10 inches, with trace amounts of sleet and icing also possible. However, convective snow bands could result in locally higher amounts, especially in elevated regions. Throughout Monday, strong pressure gradients could result in wind gusts up to 25 mph. Through Tuesday, the Ohio Valley will be stationed within an upper-level trough, promoting sub-freezing highs in the mid 20s. Some weaker higher pressure up to 1020 mb could potentially fill in, allowing for few breaks in the clouds during the day on Tuesday.
Long-term Forecast (Wednesday 01/08/2025 through Saturday 01/11/2025):
A weak cold front originating from stronger high pressure in southern Canada will push southward through Wednesday, though minimal temperature advection is likely given a weak frontogenetic signature. Rather, this will serve to promote more overcast skies on Wednesday into Thursday, with a slight chance of some flurries late on Wednesday. High pressure will then settle into the area by Thursday as part of a larger Omega Block pattern occurring at 300 mb. However, a strong upper low from a deep, positively tilted trough will generate a strong low pressure core in the southern states, and as it travels eastward, significant temperature gradients and a strengthening of upper level divergence could result in the low taking a track similar to that of a “nor’easter,” travelling up the eastern seaboard through Saturday. As it continues that track, light snow from the southwest is possible early on Saturday in Southeast Ohio. However, there is rampant discontinuity between forecasting models regarding the cyclone’s development, and as such, any discussion is purely speculative. By this time, ridging will promote temperature closer to 32 degrees to return to the area.
