Monday, January 29, 2007
Latest Thinking...Wednesday-Thursday Storm System
It has been very interesting watching the models since last week. The GFS has been hinting at some sort of winter storm for about the last 7 days now, and now the models are starting to come into some sort of agreement. The GFS and the NAM are similar with the timing of the precipitation. The OZ runs suggest the onset of the precipitation beginning by late Wednesday afternoon into the evening as the first wave moves overhead. The atmosphere will need some time to moisten up and recover from the dry northerly flow aloft on Tuesday, so that's why we're going with Wednesday night for the start. The main trough will then swing through by Thursday afternoon, creating another surge of precipitation throughout Thursday afternoon.
As always the challenge to winter weather forecasting hinges on the position of the cold air. At this time the best chance for accumulating snow/sleet will remain north of I-40. The column of the atmosphere at the start of the precipitation looks to be frozen. Sleet and or snow will likely be an issue for Wednesday night across the majority of the area; however, the OZ NAM is indicating some warm air advection on a stout 850 mb feed from the Gulf, and this could change over the snow across the River Valley to a mix of freezing rain and rain by Thursday morning.
NE OK and NW AR is looking to see snow for Wednesday night, changing to sleet by Thursday morning, with a change back over to snow by Thursday afternoon as the precipitation starts to wind down. If the warm air advection is stronger, there maybe a shot for some freezing rain on Thursday morning as well.
This is our preliminary precipitation forecast map. We'll be updating the map and our blog entries regularly throughout this event. Please log onto our blog and post comments and questions.
Posted by Drew Michaels at 9:12 PM
7 Comments:
I know some of the models have snow here, and all.. but based on past storms, we all know it will be rain/sleet They all are. Of course we will hope for some snow. I-40 north of course has the best chance. ( not a shock there.) I hope Drew is right and we get some snow though.
The new models runs are rolling in this morning and though the differences are sutle they have LARGE implications on the going forecast through Thursday afternoon. With many reinforcing shots of cold, drier air the past week, it appears that this system will not be as moisture rich as the previous ones. It will take some time to moisten the lower layers of the atmosphere tomorrow with the best shot of some light accumulations north of 1-40 with more of a rain/sleet mix south of 1-40 with some snow mixing in on the back side.
The new models runs are rolling in this morning and though the differences are sutle they have LARGE implications on the going forecast through Thursday afternoon. With many reinforcing shots of cold, drier air the past week, it appears that this system will not be as moisture rich as the previous ones. It will take some time to moisten the lower layers of the atmosphere tomorrow with the best shot of some light accumulations north of 1-40 with more of a rain/sleet mix south of 1-40 with some snow mixing in on the back side.
So basically no snow day. :(
Here's hoping for some snow for the River Valley. I'd like to see at least one blanket of snow for us before winter ends.
I'll have a new update coming up around 6 p.m. The update will include a new snowfall graphic.
So Drew what are the new totals?
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