As mentioned in yesterday's blog, the vertical profile of temperature and moisture played a big part in the precipitation type that was experienced. Due to the depth of the cold surface air and the magnitude of the warm layer aloft, most of what fell was in the form of sleet with at least some snow on top of that as colder aloft moved in last night. Notice the map on the right which probably shows that relationship better than my feeble attempt on Sunday.
Some of the reports that have come in today were rather striking; for example 3" of sleet and 1" of snow for a total of 4" of frozen precipitation at Muskogee. That raises the question regarding how much would that have been were it all snow? That is not an easy question to answer. A rather typical snow/liquid ratio is 10/1 around here. That is to say it will usually take 10" of snow to equate to 1" of liquid. However, since we are talking about ice and not snow and ice pellets at that, the answer becomes more difficult. Ice expands when frozen and filling a rainguage up with sleet pellets will also have a good bit of air in the spaces between the individual pellets, depending on their size of course. Those two effects would offset each other to a certain extent but it is very difficult to say just how much. The quick and easy answer would be to just use the standard liquid/snow ratio which would imply about 30" of snow from the sleet there in Muskogee. More than likely it would have been much less than that, but even so had that been all snow we would have been dealing with an event that would have exceeded any previous snowfall records for that area. Another quick and easy way to get around that would be to take the sleet from a rainguage and melt it right after it quit falling in order to get a better handle on what the sleet/liquid ratio would be. Mundane questions perhaps, but an attempt to put the events of yesterday in a little better perspective.
Now, that we have this system behind us, we are dealing with the bitter cold. Notice the national snow cover map on the right. With ice/snow covering the ground all the way down to the Red River, it will take a while for things to moderate. Some high clouds will persist through the night tonight and light winds this evening will become more southerly by morning. Those two effects would normally moderate temperatures somewhat, but with the extensive snow/ice on the ground, still think temperatures will make into single digits again tonight. By the way, afternoon highs today will likely set records for coldest daytime high. Tuesday should finally make it above the freezing mark with 30s to near 40 expected along with lots of sun and a light southerly breeze.
Wednesday could get interesting again. Another cold front will arrive that afternoon along with increasing cloud cover and a chance of precipitation. This system will not be nearly as strong as we just experienced but nonetheless, colder air aloft will be moving in quickly so there will be a window of opportunity for at least some snow that evening or early night. However, it currently appears that surface temperatures will be warm enough that most, if not all of it will melt as it reaches the ground. So, right now, it does not appear that it will amount to much.
Daytime highs on Wednesday will only be near 40, but temperatures will finally be rebounding on Thursday with highs into the 50s and finally above normal on Friday with highs into the 60s. Another cool front will arrive on Saturday with a chance of rain and cooler conditions but not the extremes of recent days.
So, stay tuned and check back for updates.