:: Storm Update - Sat AM 2/24
Winter storm predictions are easy to bust, and amidst the commercial wx hype and media attention, local TV forecasters were quick to embrace a relenting 00Z model run last night. 00Z runs painted a better picture for the Friday overnight, and renewed forecast discussions and statements tentatively backed off the 3-5" or -6" progs for the overnight snow event. Primary view from the 00Z runs was a slowing low pressure center in SE CO, as well as a very warm overrun that was setting up off the LLJ. The only forecast hints that were stymied was the baroclinic wrinkle that emerged over the KRGK-KONA river valley and gave rise to some elevated convection which moved SE overnight. This pumped 3-8" of snow from Prescott, WI down to KMSN.
Focus this morning turned to how the models handled the convection signatures in the 12Z runs. MPX-WFO tossed out the 00Z GFS in their early AM shift discussion, but I think that the model had some even points to grab at. Init and matchup with NAM features were good, and I think that GFS still has some better handling of the pressure gradients that are setting up troughs that spoke out from the low. Along with the trowaling comes the convective setups...and rad/sat imagry has confirmed the higher tops signature of the elevated convection acrs NE and IA this early AM. Law enforecement spotter reports this morning in these areas have indicated "thunder sleets" and FZRA acrs IA that have downed power lines.
Dewpts from TX on up into the center of the low are high, and even extend into srn NE, and model Pwat vals are consistently high in same area as well, so moisture is in place. Overrun effect still in place it seems, as sleet taps my windows at present. Radar echoes show first band of moderate to heavy precip just along I-90 attm. KULM and KRWF are now obs -SN, and my gut is that the colder air aloft is starting to seep into the north side of the system. This sets our area up for the heaviest snow potential this afternoon. Redevelopment of snow bands will depend on whether or not convection redevs to our south, and how the low track goes through the day.
For now, my concurrence is with general thinking that we get 4-7" today by sundown, with potental of 4-5" more after dark. May start as sleet/heavy wet snow and then all snow by mid-late afternoon.