Yuba- Feather Freezing Level Forecasts and Observations

Upper Yuba Freezing Level Forecasts

Seven-day times series of the forecasted freezing level over the Upper Yuba watershed from the GEFS (left image) and ECMWF ensemble Prediction System (right image) for each ensemble member (thin gray lines), control member (black line), ensemble mean (green line), and +/- 1 standard deviation (red and blue lines). Bars represent the 6-hour mean areal precipitation from the NOAA WPC. Shading of bars represent the percentage of the watershed forecasted to receive rain (green) or snow (blue), or the area within the range of ensemble uncertainty (cyan). Dashed lines represent the percentage of watershed terrain below that level. The right-hand plot shows the distribution of terrain versus elevation for the watershed. Use the menus below to select model initialization dates from the past thirty days.

GEFS	ECMWF

MicroRain Radars

The following plots show data collected from MRRs stations at New Bullards Bar and Downieville (red dots on right map). The top panel shows reflectivity shaded by color and the bottom panel shows vertical velocity. MRR data are processed using an algorithm based on Maahn and Kollias 2012 but modified to improve the representation of heavy rain. Black circles represent the snow level indicated by a radar bright band when bright band precipitation is present. The bar at the bottom of each chart shows the precipitation type (bright band:light gray, hybrid:medium gray, or non-bright band:dark gray). Both the snow level and precipitation type are derived using an algorithm modified from White et al. 2003. Raw spectra measurements are collected every 10 seconds. Each plot shows the current day’s data, with time moving from left to right. Data is updated at least once per day and up to once every hour, depending on station. Time is in UTC. For an archive of processed 5 minute data and images click here. Use the menu below to select an observation date from the past thirty days.

New Bullards Bar	Downieville

Disdrometers

The plots below show data collected from disdrometers locations at New Bullards Bar, Downieville, and the Central Sierra Snow Lab (red dots on right map). The top panel shows a scatter plot of rain intensity (mm/h) and the middle panel shows the radar reflectivity (dBZ). For the top two panels, the points are shaded according to the precipitation class determined by the disdrometer (see legend). The bottom panel shows the drop size distribution: the volume equivalent diameter (mm) is on the vertical axis, while each bin is shaded by the drop size frequency, which is expressed as a spectral number density (log scale). Measurements are recorded every 10 seconds. Each plot shows the current day’s data, updated once per hour, with time moving from left to right. Time is in UTC. For an archive of processed 5 minute data and images click here. Use the menu below to select an observation date from the past thirty days.

New Bullards Bar		Downieville		Central Sierra Snow Lab