Weathering the Weather: St. Patrick’s Day Snowstorm

snow map March 17

Whether you are sick of it or not, all the pieces have come together for yet another winter storm to affect the area tonight into tomorrow.

Accumulations: I expect a general 3-6 inches, with more to the west and less to the far north and far south. Southern areas will receive heavier precipitation but will take longer to cool down. Urban areas in Washington, D.C. and Baltimore should get less for similar reasons.

Timing:

  • 5-8 PM: Precipitation begins, starting as rain in many areas.
  • 8-11 PM: Rain rapidly transitions to all snow from northwest to southeast.
  • 11 PM-6AM: Moderate snow, heavier south of Washington.
  • 6-9 AM: Snow continues, but may lighten in intensity.
  • 9 AM-1 PM: Snow rates increase from earlier.
  • 1-3 PM: Snow tapers to flurries.

Impacts: Roads will start wet, but will gradually become covered by snow and ice overnight, affecting the AM commute. Many delays, cancellations, and closures are likely.

Confidence: Low-Medium. With the confidence being Low-Medium, there are Bust or Boom scenarios that could occur. In the boom scenario, cold air filters in faster and snowfall rates are more intense overnight than expected. 6-9 inches of snow would be possible over much of the area if this occurred. In the bust scenario, heavier precipitation misses the area to the south and the warm ground prevents much accumulation. A sloppy 1-3 inches, mainly on grass, would occur if this scenario unfolds.

Article by Josh Karpatkin, MoCo Student staff meteorologist

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