First Alert Weather: Snowfall Projections and Mixing for Sunday's Storm

Storm Overview and Timing

• ❄️ A significant storm is expected this weekend, with watches and warnings issued for approximately 175 million people nationwide.
• ⏰ The storm is projected to begin Sunday morning, with snow accumulating by sunrise and continuing through the afternoon.
• ❄️ Precipitation is expected to start as snow for everyone, but mixing may occur later in the day.

Understanding Precipitation Mixing

• 🌡️ The type of precipitation (snow, rain, sleet, freezing rain) depends on atmospheric layers, not just surface temperature.
• 💧 A snowflake hitting a warm layer melts into rain, and if it refreezes before hitting the ground, it becomes sleet or freezing rain.
• ⚠️ Freezing rain on contact is described as the most severe form of precipitation, though it's not heavily anticipated in this specific scenario.

Snowfall and Mixing Projections

• 🏙️ For the central swath of the storm, including all five boroughs of New York City, snowfall is estimated between 8 to 12 inches, with a possibility of 12 to 14 inches.
• 🏖️ Areas to the south, like the Jersey Shore, may experience warmer temperatures (around 34 degrees) leading to potential rain or mixing.
• ⬆️ To the north of the city, snowfall is projected to be around 6 to 10 inches.

Cold Air and Lingering Effects

• 🥶 The forecast includes a First Alert for Saturday due to extreme cold, and another for Sunday because of the snowstorm.
• 🗓️ The cold air is expected to persist well into February, with temperatures remaining below the freezing mark for an extended period.
• 📈 Models like the European, GFS, and NAM provide varying snowfall totals, with the European model indicating over a foot of snow despite accounting for sleet.