Who Did & Who Didn’t

To call this storm challenging would be more than an understatement.  Fort Supply ended up with 25″ of snow and 5′ drifts.  Harper county is essentially cut off.  Moderate to heavy snow is now falling in north-central and northeastern Oklahoma.  There are still a variety of watches and warnings, including the Blizzard Warning for northwestern Oklahoma that will go until 1pm.

graphic112The big question:  what happened to the snow forecast for OKC?  The answer is long and complicated, but I’ll quickly touch on the two big culprits…the warm nose and the dryslot.

The warm nose is what got us yesterday.  The National Weather Service in Norman sent up a special weather balloon yesterday around 1pm.  The resulting sounding (snapshot of the atmosphere) showed a layer of very warm air above the surface.  This was warmer than depicted on the computer models.  Combine that with warm surface temperatures, and basically we kept precipitation as some much needed rain in OKC.  Just to the west and north of OKC, surface temperatures dropped below freezing.  That combined with the warm layer above brought sleet and freezing rain.  The sleet and freezing rain made it to Canadian and Kingfisher county, and stalled for most of the evening.

The other big flaw–the dry slot.  This is a wedge of dry air that comes in on the southwest side of the storm system.   The dry slot moved across last night and early this morning.  Here’s that it looked like on the Water Vapor imagery:

graphic29If you look between OKC and Dallas/Del Rio, you see that wedge of dry air punching in.  That took a lot of the upper level moisture away from this storm.  To the left of that is the wrap-around which is providing the snow to north-central Oklahoma this morning.  I mentioned a few days ago that this dry slot could be a factor for southwestern Oklahoma…but it ended up being more of a factor for the central part of the state.

Right now we’re tracking an area of rain and snow southeast of a line from Ponca City to Edmond to Ada.  This is moving south and southeast.  The metro will get some snow out of this.  A good north wind will blow this snow around.  We just got some great video from Chris Caldwell in FAST Unit 55 who is in Ponca City.  He’s had some good snow over the past couple of hours.  We should get some new video from Woodward soon.  Covering the story in northwestern Oklahoma is far more difficult.  25″ of snow can do that…

Andy

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3 Responses

  1. The answer as to what happened to the snow for OKC is the same answer that always happens. If you would forecast with the OKC statistical data for snow in mind, you would realise that you would be much more accurate to forecast no snow than to believe we are going to get 4 to 8 inches. Look it up. When was the last time that happened?

  2. why isn’t stuff like this looked at when making a forecast?

  3. […] at least we have KOCO’s meteorologist Andy Wallace to explain what happened. Here’s a bit of what he had to say: The warm nose is what got us yesterday.  The National […]

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