Moisture/Lift/Instability

850 mb Temperature Advection	850 mb Frontogenesis	850-700 mb Frontogenesis	700 mb Frontogenesis	700-500 mb Frontogenesis

850 mb Frontogenesis 800-750 mb EPV	700 mb Frontogenesis 650-500 mb EPV	Mid Level Lapse Rates	850 mb Moisture Transport

Mesoscale bands of heavy snow are favored where frontogenetic circulations are embedded within an unstable thermodynamic enviroment (slantwise or vertical) .  Geostrophic Equivalent Potential Vorticity (EPVg) < 0 suggest parcels will be unstable to slantwise motions within that layer of the atmosphere. EPVg as an ingredient to mesoscale banded precipitation is best evaluated in a 50-100 mb layer directly above where frontogensis is being analyzed.  If EVPg is < 0 in this layer, the ageostrophic frontogenetic circulation will be enhanced. If elevated CAPE or steep lapse rates are also present, the parcels unstable to slantwise motion will become unstable in the vertical, resulting in upright convection.  Thermodynamics SFC Wet Bulb 925 mb 850 mb Freezing Level Precipitation Type and Lake Effect Snow Near-Freezing Surface Temps Critical Thickness Lake Effect Snow 1 Lake Effect Snow 2 HRRR Snowfall and Precipitation Type Forecasts 2 Hour 4 Hour 2 Hour 4 Hour RAP Precipitation Type Forecasts This requires Javascript for animation of the graphics. You will need Javascript enabled to view this. f01 f02 f03 f04 f05 f06 f07 f08 f09 f10 f11 f12 f13 f14 f15 f16 f17 f18