Winter storm outlook very complex but we all end with snow

After a days stuck in the 20s and nights into the single digits for many, Maryland warms up just ahead of a new storm. The temperatures will be flirting with freezing, which makes the type of weather very tough to pin down. For the purpose of simplicity, I want to use this blog to break down the basics. So I will not post elaborate computer models or get too technical.

In the slideshow, you will find projected radar images from our in-house Adonis model, which I tend to agree with here.  The last image shows my 'first call' for snowfall with a potential spread high seen with the '+'. This is my interpretation of the storm, which is actually lower on snow than some models have indicated.  What I have considered are the following:

• Arctic air is departing, but the ground is cold. Even after a mild day, we have some retained cold
• The Chesapeake Bay is colder than normal. Ice was seen on the Severn River from our weather cam at the US Naval Academy. The water temperature at Thomas Point Light House is 32F. Wind off of the water will not warm us much, it will all be from the storm itself.
• Our weather pattern has not produced much snow this winter. The trend is often your friend. However this is a special case considering the extensive arctic blast we just had and a slightly different storm track. All of that puts Maryland at a higher risk.
• The computer models have overdone the precipitation on most of our storms this winter.  There was a surge overnight in expected snowfall, much higher than I can accept for now.
• While we could have a mix at the start, a chilly rain will fall for Baltimore and Annapolis most of Wednesday. It will turn back to snow in the evening. Places north that stay as all snow, will get more, but could end up with limited accumulation since temperatures will be very close to freezing.

The Maps:

Start Time Wednesday morning: This may not be exactly at 5am. I would say between 3am and 8am.  There could be a few hours with borderline temps and a mix even in Anne Arundel County. There's a better chance of early ice north, as rain will spread from south to north.

Noon Wednesday: A chilly rain for much of the region. Annapolis, Baltimore, Bel Air all will have temps in the mid 30s, just above freezing. There will be a region with a mix or wet snow north. This is depicted in southern PA, Baltimore's Hereford Zone, near Westminster, and west.  If this areas stays snow, it will be heavy and wet. I don't expect too much accumulation during the day, and with temps near freezing, roads will be mostly wet in the afternoon.

Wednesday Evening: The turn over!  This is part two of the storm. The upper level energy (not the surface Low Pressure) will determine when the cold air returns and we go back to snow. The precise time will make a big difference as to how much we get. There will be a burst of moderate to heavy precipitation that could bring snowfall rates of 1 inch per hour at times.

Wednesday Night:  Going to all snow. This will be the heaviest snow. Overall we should have 4-6 hours of snow. As the temperatures drop, and considering that this is night time, roads that are wet will turn icy.

Thursday 'Early Morning': Regardless of how much snow actually falls, it will be moving out long before daybreak. As temperatures settle back into the 20s, what was wet, will be icy under that layer.  I don't make any calls for schools, despite how I like to lookout for my fellow teachers. However the road crews will have their work cut out for them.  If you have no choice but to get out and go to work, if you park your car outside, leave the wipers up or they will freeze to the windsheilds.

Snow Totals:  This is my first call. By the time you read this, there may be many more computer models to guide amounts, so there will be some fluctuation. This is my attempt at what I feel confident that we will get. Most of this will be from the second surge on Wednesday evening.  Places that stay colder during the day, as well as turn back over to snow sooner will get more.

The question mark '?': That is a region when this may stay all or mostly snow. This is also dependant on whether that get or miss the second surge of heavy snow late Wednesday. That is the low confidence zone, but it is well outside of Baltimore.  Ski areas in central PA and western MD, and West Virginia will get a lot or a little, but they will get snow.