Wintry Mix Wednesday.


Tuesday, February 19th 2013, 6:05 pm
By: News On 6


Complicated forecast for Wednesday/Thursday with the potential for some wintry weather along with the potential for even some thunder by the time it is all over with. As you can see from the QPF map on the right, there is also the potential for some widespread, soaking rains which will put another dent in the ongoing drought situation. This will not be a drought breaker, but will certainly help.

The vertical distribution of temperature and moisture will be critical tomorrow and that is where most of the question marks come in. Clouds will be moving in tonight but below the cloud deck is a layer of very dry air near the surface. It will take awhile for the precipitation that will be falling from those clouds to saturate the near surface layer. However, that is a cooling process which means that although temperatures may start off near freezing first thing in the morning and then recover somewhat during the day, as soon as the precipitation reaches the surface temperatures will fall back again. Currently it appears that we will be above freezing, but it will be close. Given the uncertainties, that makes it very difficult to give an estimate of how much, if any, wintry precipitation we can accumulate.

Right now, it appears that when the precipitation starts, it will start off as a mixture of sleet/snow/rain, probably change over to all snow for a time, then eventually back to all rain by late in the day. That is because warmer air aloft will be spreading over us and at the surface a gusty E wind will eventually become more SE by Wed night. Again, a difference of a degree or two in temperature will make all the difference in the world regarding precipitation type and amounts. The timing of when the precipitation starts is dependent on how quickly the dry lower layers can saturate. For the Tulsa metropolitan area, that probably means not till mid to late morning, then continuing through the afternoon, night, and into the day Thursday.

The rain will be ending by mid-day Thursday followed by a few breaks in the clouds. Friday will then be sunny and cold with lows in the 20s and daytime highs only in the lower 40s. Although another piece of energy aloft will be passing overhead Saturday, it looks to be moisture starved so will keep the forecast dry. Temperatures will then be moderating over the course of the weekend with gusty southerly winds returning on Sunday and daytime highs well into the 50s if not near 60. Another system will be arriving early that following week with another chance of rain. There are also indications of a more significant system affecting the state along about the middle of next week.

Lots going on with a more active pattern that is developing, so stay tuned and check back for updates.

Dick Faurot