Winter Weather Advisory for Tonight, Monday.

As might be expected, this round of very cold weather has impacted soil temperatures. The map on the right courtesy of the OK Mesonet shows the soil temperatures as of early this morning at 2" under sod. Earlier in the week, those numbers were well into the 40s and even some low 50s. That, of course, may have a bearing on how much wintry precipitation accumulates later tonight and into the day Monday, although there are also other factors to consider.

The cold surface ridge of high pressure responsible for the coldest we have been all season will be sliding on eastward today allowing our surface winds to return to a SE direction by afternoon and a southerly direction for tonight and Monday. Usually, for a winter weather event, the surface ridge center will be more to the NE of us which would produce a more NE surface wind which would keep funneling cold air in at the surface. That is not happening this time around. However, this ridge is very cold and very dry so it will be re circulating some cold, dry air for at least awhile. Eventually, the strength of the southerly winds will tap into air that is relatively warmer and more moist, but the timing of when that happens and the levels in the atmosphere in which that will occur are the main forecast challenges.

Also, the disturbance in the upper atmosphere that is heading our way from the southern Rockies does not appear to be overly impressive. However, it will have enough punch to produce a round of wintry precipitation starting in the western part of the state by evening and spreading our way overnight.

For today, you can expect SE to S winds increasing to 10-15 mph along with increasing cloud cover. Temperatures should make it into the mid-upper 30s by late afternoon, then fall back to near freezing after dark. We should start seeing snow falling before midnight and the initial low moisture content should produce enough evaporative cooling to keep temperatures at or below freezing through the morning hours of Monday. However, the strong southerly winds will at the same time start tapping into warmer air so the precipitation should be transitioning to a mixed bag with a mixture of snow/sleet/rain/freezing rain all possible at some time. This transition will likely be last to occur for the more NE counties so they will have the best chance for a more significant snowfall.

Total liquid equivalent of the precipitation does not appear to be any more than ¼", and if that were to all be snow and stick on the ground then 1-3" with locally higher amounts would be expected. However, given the southerly winds and the likelihood of a mixed bag of precipitation then that probably will not occur. However, travel late tonight and into the morning hours of Monday will likely encounter some slick spots, particularly on elevated surfaces.

After that, the rest of the week will be much milder. Valentine's Day looks pleasant with partly cloudy skies, light winds, and cool weather. Wednesday will see another rapidly moving disturbance aloft with clouds and a good chance of rain, possibly even some thunder. That will be followed by mild weather going into the coming weekend.

So, if we can make it through Monday, we should be in pretty good shape for the rest of the week.

As always, stay tuned and check back for updates.

Dick Faurot