Spring Is Fast Approaching
Winter has been relentless since mid-January and shows little signs of slowly down. However, meteorological spring is fast approaching, and begins March 1st. By March 20th, the astronomical spring begins which means warmer times are ahead. But regardless of what season we are in, winter or spring, with each passing day in February the sun gets stronger and higher in the sky. While this has obvious effects such as longer daylight hours and climatologically warmer days, it also has forecasting implications. How you ask? We'll explain below.
One of the biggest challenges in forecasting early or late season winter storms is how the falling precipitation will react when making contact with the ground. Just a month ago in January when there was light snow with temperatures of 15-20 degrees and a relatively low sun angle, it was obvious any snow that fell would easily accumulate to all surfaces whether it was grasses, car tops, or pavements. However, now that days are longer, daytime temperatures typically warmer, and the sun stronger, the odds of snow melting on the ground greatly increases. This is especially true on pavements. For instance, the storm from February 13-14th is a great example. While there were widespread totals of 0.5 - 2.0" across MD, PA, and NJ, pavements and sidewalks in many instances only remained wet or briefly "slushed" up when heavier bursts of snow fell. This resulted in just a salting event for people in the snow removal industy, despite upwards of 2.0" of snowfall (on colder surfaces). As we head into late February and March, this becomes even more of an issue, and pavement accumulations during the daylight becomes very rare. For reference, the late February sun angle is approximately equivalent to that of late October.