Before getting around to how much snow we may receive, thought perhaps some of you would like to have a better idea of how to measure snowfall and how much is actually on the ground at any one time.
CoCoRaHS which stands for Community Collaborative Rain Hail and Snow network has some excellent guidance. I mention this because we are looking at a significant winter storm on Tuesday and given the strength of the winds it will make it very difficult to get an accurate measure of the actual snowfall and accumulation totals. There will likely be some very exaggerated numbers floating around by the time it is all said and done so hopefully by following this guidance, we will have more accurate information.
As far as the storm itself, all the available data that has come in during the day today continues to support a winter storm the likes of which have not been seen around here for a very long time. This will be a very wet system and if it were all rain, it would easily produce 2" or more of rainfall which quite frankly is badly needed to alleviate the drought conditions and high fire danger of the last few days.
Here is how it time line looks to be taking place. Around the mid night hour, give or take an hour or so depending on your location, light precipitation should be developing initially in the form of drizzle or light rain which with temperatures near freezing would quickly transition over to freezing rain or sleet. For locations along the I-44 corridor that should quickly transition over to snow with heavy snow likely from the late night hours through much of the morning and gradually tapering off during the afternoon and evening hours. For locations further south, for example along and south of I-40, there will be a longer period of freezing rain and sleet before changing over to snow during the morning and early afternoon hours. Obviously, that will have a major impact on how much actual snow there will be as the more rain/freezing rain/sleet that falls will lower the amount of snow that falls.
Having said all that, we are still looking at total snowfall which could exceed a foot in some locations and if so, it could result in a record amount of snowfall for any one event. The current record is 12.9" back in March of 1994. On top of that, we will have strong northerly winds which will produce blizzard or near blizzard conditions for much of the state which also means significant drifting of the snow making travel extremely difficult if not impossible.
Those winds and the bitter cold temperatures will also produce extremely dangerous wind chill values which will likely be in negative territory for much of the day Tuesday and almost certainly all day Wednesday. If our skies are clear, below zero temperatures are likely for Thursday morning and the last time we saw temperatures that cold was back in Feb of 1996. Needless to say, this is shaping up to be a very significant winter storm not only for us but for much of the country which will take days to recover from.
We are not expected to get back above freezing till over the coming weekend so this will also be a prolonged period of cold conditions and this snow will stick around for quite awhile. In fact, we are seeing preliminary indications that late Sunday or Monday of next week could get interesting as well.
So, stay tuned and check back for updates.