Monday Update on Season’s Second Major Winter Storm

After analyzing the forecast models for the past three hours and comparing the trends between the ensembles, operational and control “runs” of the North American Model (NAM), European, and Global Forecast System, I have decided to cut to the chase with this post and present to you my new forecast graphics that you will only find on

The first image is my first take on how much snow and sleet may accumulate before a change over to freezing rain occurs on Wednesday afternoon:


The next image is my first take on how much ice accretion (accumulation from freezing rain) may stick to untreated surfaces, trees, and power lines:

This exact details regarding when the change over from snow/sleet to freezing rain and how long temperatures remain below freezing Wednesday afternoon will have a major impact on the forecast. For those of you who live in the typical colder, sheltered-valleys you might want to fill up your propane tank so that you can cook food in the case of significant ice accretion from freezing rain. Some of the forecast models are easily dropping over a half-inch of ice (the kind that hangs on power lines and trees).

Given how wet the ground is from the recent rainfall, there is the potential for scattered to widespread power-outages across portions of the Washington Region (mainly north and west of the cities). With that said, even Baltimore and Washington are under a moderate threat of receiving up to a quarter of an inch of ice from freezing rain. Hopefully Sleet (frozen rain drops that bounce) will end up being the primary precipitation type, but everyone should be prepared should the region experience a prolonged period of moderate freezing rain which could cause major problems including scattered to widespread power outages should a long-duration, freezing rain event materialize. The National Weather Service was brilliant to issue Winter Storm Watches this morning to give folks time to prepare today.

Updates to come as more model data becomes available.