There are very few things that qualify as lead pipe cinches when it comes to Oklahoma weather, but if we do not have a blanket of snow across much of the state by Noon Thursday, I will be very surprised. The amount of snow is another matter altogether and that is where the devil gets into the details. More about that in a moment.
First off, here is how the timeline now appears to be shaping up. Although we have already had some reports of ice pellets this morning and early this afternoon, those have been minimal and have created no problems. There is a slight chance of a few sprinkles, ice pellets, or maybe even some light freezing rain around sunset, but again no problems are expected. The precipitation is expected to be rapidly changing over to snow after sunset and should be moving in from the NW with snow along the I-44 corridor by 10 or 11 PM tonight. That will be quickly spreading to the SE across the rest of Eastern Oklahoma with widespread snow falling through the early morning hours and ending from west to east by late morning or early afternoon at the latest. In fact, for Tulsa it appears that the bulk of the snow will fall between the hours of midnight and noon.
The amount of snow is always a difficult matter as it depends on the liquid/snow ratio which will vary from event to event, it depends on how much precipitation first falls as liquid or ice before changing over to snow, it depends on how much melting takes place before starting to accumulate, it depends on how much the wind blows and drifts the snow and any compaction that may occur…..the list goes on and on. As a general rule, the typical snow/liquid ratio for this part of the world is usually on the order of 10/1. A heavy, wet snow will have a lower ratio and a dry, fluffy snow will have a higher ratio. So, assuming we have a good handle on how much liquid a given event will produce, we can translate that over to an approximate amount of snow that may be expected to fall.
Another factor is that with snow as is the case with rain showers, there will always be some locations in which there will be a locally heavier amount of precipitation. We refer to those as local snow bursts which can at times become organized into a snow band that will be more persistent and can drop as much as twice as much snow in a more localized area than would occur over the broader, more general area that we are forecasting for.
Having said all that, what are we looking at for this particular event? Well, each computer solution that has come in over the last several days has come in progressively wetter than the previous solution. So, the trend is definitively up and some of the point products suggest one half inch of liquid, if not more, which could translate into as much as 5" or more of snow given the factors mentioned above.
Again, this is no lead pipe cinch but I would expect a widespread blanket of 2-4 inches and local amounts which could exceed 6" with the heaviest amounts north and progressively lighter amounts to the south.
By the way, not going to say much about it now, but it is starting to look like another winter event is shaping up for Sunday.
As always, stay tuned and check back for updates.