Des Moines AFD
Attention then turns to a
strong PV anomaly for Friday and into Saturday. This is expected to
result in rather deep trough, and strong jet dynamics capable of
creating a robust surface cyclone. There is still a considerable
amount of difference among ensemble members, as well as difference
among long term deterministic model solutions for this system.
Earlier runs favored Saturday morning and afternoon for
precipitation across northern Iowa, but now is showing a trend to a
Friday afternoon-evening arrival. The 12z deterministic ECMWF
remains further south with the system and its strong deformation
zone axis, which could present accumulating snow as far south Hwy.
20. The GFS remains further northward, with the heavier
accumulations more in Minnesota. GEFS members are split between
northern and southern solutions. At this time, it appears the at
least far northern Iowa will be favorable for accumulating snow
potential. Central Iowa will be more uncertain. In the coming days,
will need to continue to monitor trends in the track of the system.
If this system becomes as strong as deterministic guidance is
indicating, dry slot fun could become an issue with the eventual
snowfall forecast as the event draws closer.