Accumulated Net Degree Days (Modulated Freezing Degree Days and Thawing Degree Days) and Accumulated Freezing Degree Days are calculated from NOAA Real-Time Mesoscale Analysis (RTMA) and National Blend of Models (NBM) for forecast guidance. ERA5 Percent of Normal Data are calculated using 1991-2020 ERA5 Climatology. Ice Time Outlooks provide guidance on the likelihood of water freezing or where conditions are favorable for ice thawing/breaking-up over the next 9 days using several meteorological parameters. For melt, the ITO uses Accumulated Net Freezing Degree Days over the season to determine where ice cover may be present. Please consult actual ice and river flow conditions, when using this product.
