Does it matter that it snowed if it didn’t stick? It is sort of like asking if a tree falls in the woods, but nobody is around, does it make a sound? That is one common trouble spot forecasting snow in a season with marginal winter conditions. Snow falling is enough to satisfy some people. But if the ground is warm and it doesn’t lay and stay, or even pile up to measure, then many others won’t see validation.
I got 4 inches of snow at my house. That was within range of my forecast on the north side, but it doesn’t matter to Baltimore. In fact, there were three storms that hit this region in the past 6 days. Both Christmas Eve and December 26th each produced 3 inches for a combined weekly total of 10 inches of snow. That blows away last season and half of a normal Baltimore season. Why is that important? Because it is still part of our metropolitan area and proof of how widely varied our weather conditions can be.
Rather than get too technical, I just want to point out the headlines. You can go back and look at my prior two posts and compare notes:
- First call for snowfall
- Final call for snowfall
My Grade: B
I have been hard on myself and admit the lack of snow accumulation for half of our area. I admit that less fell for most on the north side (except in PA). However the overall dynamics behaved like I said with the exception of the window of dry air and late start of our snow. That hurt the snow that did fall after daybreak.
Please read my notes below and see if you agree. Then share your thoughts. I am not looking for praise or consolation. Just curious how you interpret what I said, how I explained my forecast, and what you got along the way. I know some will be angry and Fail me. Other will be too kind and give me an A. This one has an explanation that goes beyond the dog eating my homework.
Please be honest and share your thoughts on this on my Facebook page. If you want to vent frustration, I welcome it. Only after you read why it ‘went down like that’. Also read Winter Storm Forecasting Manifesto for what I consider when making a snow forecast.
What went wrong in this storm?
1) Virga and the dreaded dry slot! The primary reason the snow did not lay and stay on the ground for many that snow started too late.
At first there was about 2-4 hours of potential snow missed due to virga. It was seen falling on radar, but it did not reach the ground. That was between 2 AM and 6 AM. Secondly, the dry push of air that stayed with our region until about 9 AM. That what I pointed out this morning, as the old storm was winding down and the new one off of the southeast coast was taking over. The old Mid West Storm was stronger than expected, which is why it was able to push in that dry air that was not anticipated.
Watch the video clip below of the radar between 7-9 AM as the dry slot filled in between storms.
If the snow had started earlier, not only would we have had more snow falling, but also it would have happened before daylight to coat the ground and help keep the ground cold. That would have allowed much of the other flakes to stick.
BWI recorded 5 straight hours of snow. The measurement there was only 0.4” of snow and 0.16” liquid equivalent. This is lower than my forecast there and would only total to 1.5-2.0 inches of snow if everything stayed. However considering the missing hours earlier, I still contend that we should have be very close to my 3 inch mark.
2) Little to no snow accumulation south of Baltimore. I had included Annapolis, Washington, and parts of the Eastern Shore with up to 2 inches and that didn’t happen. Snow did fall in some of these areas that could have easily added up that high, but it was too warm to stick.
What went right with the storm?
This is not a cover up in any way. I have a long history of pointing out mistakes and owning up to missing a forecast. This one did what I expected it to do.
1) It snowed. In fact it snowed farther south than Baltimore into Annapolis and the Eastern Shore. This region did not get accumulation as I called, but it got the flakes, even with a mix, while other outlets had them as just rain.
BWI recorded 5 straight hours of snow. The measurement there was only 0.4” of snow and 0.16” liquid equivalent. This is lower than my forecast there and would only total to 1.5-2.0 inches of snow if everything stayed. However considering the missing hours earlier, I still contend that we should have be very close to my 3 inch mark. (Yes, I repeated this from above)
2) North side snow. While most of the reports were lower than my first call for 3 inches or more, I held on to the notion of snow even after some local forecasters this morning called it done before it got started. The northern areas would have been better served with a 1-3 inch expectation. The 4-inch reports and higher were in Pennsylvania. At least the local ski areas got hit and are now open for the season.
3) I said the storm would be stronger than projected based on the model bias with the last few storms. In fact both storms were stronger. The primary Mid West storm being stronger gave us the dry slot in the early morning. The secondary storm cranked off of the coast in a hurry. In fact the intensity is what allowed the dry slot to fill in. For a while many though this was a complete bust, but holding patience, I had confirmation of the return of the moisture. That was a small victory with over 400 reports on my Facebook page just during the 9 am hour.
3) The burst of snow between 9 AM and 1 PM. I made this bold timing in my final call and it is exactly what happened. In fact it is likely what saved the snow at all today as the upper level energy moved to enhance the coastal storm. We were just on the edge of that happening and it verified at this time.
Please share your thoughts and my grade on my Facebook page regarding this article.
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