Short-term Prediction Research and Transition Center

NESDIS Snowfall Rate Product Details

SPoRT has closely collaborated with Huan Meng at NOAA/NESDIS/STAR to engage with NWS forecasters to assess the application of the passive-microwave derived NESDIS Snowfall Rate product in operations. The first assessment was conducted during the 2014 winter to determine the operational utility of the product in operations as it relates to radar gaps, beam blockage, and tracking of snowfall rate maxima. In 2014, the initial snowfall rate product was derived from AMSU and MHS sensors onboard NOAA-18, -19 and MetOp-A, -B. The product was produced at NESDIS and SPoRT converted it to an AWIPS/NAWIPS format for distribution to NWS partners. At that time, up to 8 land-only snowfall rate retrievals were available per day limited to regions with a surface temperature greater than 22 degrees Fahrenheit and maximum detectable snowfall rates of 2 inches per hour (for snow to liquid ratio of 10 to 1). Forecaster feedback from the first assessment was positive in that the product was useful for improving data coverage where radar was lacking and valuable for tracking snowfall maxima in combination with other satellite observations but forecasters desired improved latency. The product developers addressed forecasters concerns by utilizing Direct Broadcast data where possible to reduce latency to 30to 60 minutes and developed a merged snowfall rate product with a temporal frequency of 10 minutes. Meaning, the passive microwave swath is complimented by NSSL’s Multi-Radar/Multi-Sensor (MRMS) data to increase situational awareness of snowfall rate and fill in the gaps between polar-orbiter overpasses. The developers at NESDIS added S-NPP ATMS snowfall rate retrievals to the product and improved the algorithm for use in colder regimes in order to expand to an Alaska domain. The product was assessed again during the 2016 Winter season during which forecasters found the swaths and merged product valuable for identifying snowfall in data-deprived regions. The example to the right highlights use of the product to increase situational awareness of a rain to snow transition event.

“Much of the precipitation across West Virginia was still in the form of rain… with an area of snow extending from northwest PA across Ohio into southwest portions of the state. There appears to be several observations of rain across Ohio with surface temperatures of 32 to 35 DegF where the SFR product indicated snow in the clouds” – Charleston, WV WFO.

Prior to the 2018 winter assessment, additional observations were added from the SSMIS instruments onboard DMSP -F16, -F17, and -F18 as well as GMI onboard NASA’s GPM. There were also improvements to the snowfall detection algorithm. Forecasters continued to provide feedback that the NESDIS Snowfall Rate product is valuable for use in radar-deprived regions, depicting where the heaviest snow is falling, and verifying model performance. SPoRT and NESDIS have continued to collaborate on research to operations / operations to research activities since 2014 to transition and assess the NESDIS Snowfall Rate product in the operational environment. Targeted training, assessments, and interaction with forecasters has led to product improvements and increased usability and applicability of the NESDIS Snowfall Rate product in operations.

See the JPSS Science Seminar “NESDIS Snowfall Rate Product and Its Applications” to learn more about the NESDIS Snowfall Rate algorithm, product, and applications