Another late winter storm will affect much of the Upper-Midwest over the next 24-36 hours. Following are some specific area forecasts:
Rochester, MN:
Snowfall starting at 10PM tonight, with total accumulations of 10 inches.
Minneapolis/St. Paul:
Snowfall starting at 9PM tonight, with 6 inches total accumulation in the northern portions of the metro, and 8 inches across the south.
St. Cloud, MN:
Snow starting at 8PM tonight, with 5 inches total accumulation.
Iowa City, IA:
Light snow and rain starting 9PM, changing over to all rain by midnight, and then back to snow after 3 AM. Total snowfall accumulation: 1 inch or less, mainly on grassy and raised surfaces.
Cedar Rapids, IA:
Light rain and snow starting 9PM, and changing over to all snow by 3 AM. Total snowfall accumulation: 1 inch across the south (Eastern IA Airport) and 2" in the north (Marion, Hiawatha).
Discussion:
Interesting late winter storm is shaping up in the Upper-Midwest. It appears that this system will tap into a generous amount of moisture, despite the fact that the low is not based in the TX/NM/OK region which is often associated with large moisture transport winter systems. In the upper-levels, trough in the WRN CONUS will deepen through the next several days. In the near term, Lead impulse in SERN CO and secondary wave lifting through NWRN MN will affect the WX in the Upper-Midwest for the next 24 hours. By 12Z tomorrow, shortwave axis will be aligned along the IA/NE border. Meanwhile, SFC low pressure will track through SRN IA while the H85 low tracks from the Sioux Falls towards Chicago. Isentropic upglide of high theta-E/mixing ratio airmass on the 285K to 292K surfaces around to the NERN and NRN side of the low will commence in NERN IA and SERN MN by late afternoon as 50kt LLJ noses into the area. Examination of the H7 VV fields along with -10C to -15C isotherms indicates impressive UVV's in zone of maximum snow production. It also appears that banding with enhanced snowfall rates will occur across SRN MN with negative equivalent potential vorticity along with strong GQ-forcing. Concerning model performance, GFS has been most consistent from run to run; while the NAM's has been trending back to the S more in line with the GFS.
- bill