Freezing Drizzle Wed Night, Weekend Looking Good.

In yesterday's blog, I tried to show how the wind flow aloft has led to the extremely cold weather of the last few days, not only here in OK but for much of the rest of the U.S. Then I found the chart on the right which I thought provides a good explanation of a term that you may have noticed has been bandied about recently; "Polar Vortex". The chart provides a very good explanation and is from the good folks at the NWS office in New York. Hopefully, that helps to explain the situation a little better as well.

As you can see, this is a normal part of how the atmosphere behaves and now that the wind pattern aloft is returning to a more normal configuration, we can expect milder conditions. In fact, that has already occurred today as you can see from the first map on the right, courtesy of the OK Mesonet. Quite frankly, am pleasantly surprised that we warmed as much as we did today as typically these arctic air masses erode much more slowly and the warm-up is usually much more gradual. Notice the second map on the right, also courtesy of the OK Mesonet which clearly shows how significant the warming has been.

So, where do we go from here is the next question. Unfortunately, the air aloft is still quite cold and dry and with some energy aloft coming our way from the SW and a brisk southerly fetch at the surface, moisture will be on the increase. That will produce cloudy skies for Wednesday and the vertical profile of temperature and moisture suggests some drizzle or patchy light rain will be developing by afternoon. Unfortunately, those same parameters also suggest the column of air will be at or below freezing in the lower levels for much of this event but without any significant moisture at the level in which snow usually is formed. The result is expected to be some freezing drizzle or light freezing rain for the evening and overnight hours of Wednesday night. Amounts will be light, but it does not take much of that to cause problems. Temperatures will start off just below freezing in the morning, but the cloudy skies will keep things from warming much more than the mid 30s during the day before the precipitation starts.

Thursday should have a break as the system aloft moves on eastward, but cloudy skies will keep us in the 30s during the day. A stronger system aloft will be moving across the state Friday, but by then the temperature profile at the surface and aloft will be warm enough for a cold rain event and all the precipitation should be liquid. Totals could approach an inch as this looks to be a very wet system.

The weekend looks promising as that system moves on eastward followed by clearing skies. Light NW winds Saturday and brisk SW winds on Sunday along with some sunshine will allow temperatures to make it well into the 50s and perhaps even 60 by Sunday afternoon. Another cold front will arrive by early Monday followed by northerly winds and cooler conditions, but this will be a Pacific system so nothing too drastic. In fact, temperatures will likely remain at or above normal through at least the early to middle part of next week. Also, after Friday, the forecast looks pretty dry. In fact, the preliminary indications for much of next week suggest relatively mild, dry conditions.

So, stay tuned and check back for updates.

Dick Faurot