Saturday, February 08, 2014

Here We Go Again.. MORE SNOW


All I can say is WOW!!  What a winter we have had.  I remember winters like this growing up in the 80s here in Arkansas.  

Snow amounts averaged around 1-3'' across the state with some places getting up to 4 inches Friday night.  The very cold temperatures allowed for what is called a high snow ratio.  We typically have snow ratios around here of 6:1 or even 10:1.  That means if 6 inches of snow fell, if it melted, it would be the equivalent of 1'' of water.  If it's colder, then 10 inches of snow for every 1 inch of water.  This snow was almost a 20:1 ratio which doesn't happen often around here.  It was that dry powerdery snow due to temperatures in the low to mid 20s.  This is why it was tough building a snowman or having a snowball fight.  The water content in the snow was very low.  The total amount of water officially at the Little Rock airport was .14''

I will admit, we got a little more than I thought.  We were thinking an inch or two at most, but instead, I got 3'' here in west Little Rock.  The airport did officially receive 2.5'' and North Little Rock received 2.2''.  So it wasn't too far off.  Just a little snow and ice can cause BIG problems eh?

Now we have yet another winter weather event heading our way for Monday afternoon into the very early morning hours of Tuesday.  While it's only Saturday, it appears this next system may have a little more moisture.  The target area will be central and northern Arkansas for the highest snowfall amounts, BUT southern Arkansas, you could easily have winter weather too.  Don't like this stuff?  There's good news for you.  I think a warm up is on the way by the end of the week.  How long this lasts is a good question.  I keep an eye on what are called teleconnective indices, especially the arctic oscillation index.  When this is negative, it usually favors cold air and a suppressed storm track.  When it's positive, we usually warm up.  All signs point to this staying well negative through much of the month so I suspect we're not done with the cold air yet. More on that later, let's talk about the round on the way Monday into Tuesday morning.

The models are not in total agreement on how this will play out so this is still subject to change.  I will use maps from weatherbell.com using the Global Forecasting System.  Remember in these maps, it shows the amount of precip over the previous 6 hours.  The red line is the 32 degree line.  Blue is snow, green is rain, orange is sleet, and purple is freezing rain.  Here we go.

At noon Monday, a new area of cold high pressure is located just north of the state off this map.  The black lines (isobars) are oriented in a way which indicates an east to northeasterly wind flow at the surface.  This is favorable for winter weather in Arkansas.  There's a surface low in the Gulf just off the coast of Texas.  Moisture is building and snow is entering Arkansas Monday.

Things really get cranking (according to this 1 model) by Monday afternoon.  Moderate to heavy snow acorss western and portions of central Arkansas to sleet and freezing rain south.  PLEASE REMEMBER, THIS IS NOT A FORECAST.  IT'S A MODEL.  WE USE THIS AND OTHER PIECES OF DATA TO GUIDE OUR FORECAST.
Things are still going from 6PM to midnight with the back edge moving though.
The majority of the precip may be over by the time you wake up Tuesday AM.
The GFS indicates at least 2 inches of snow and maybe up to 5 or 6 in a large swath from NW and west central AR though the metro and towards the east.
IN SUMMARY, THIS CAN STILL CHANGE DEPENDING ON THE TRACK AND STRENGTH OF THE LOW.  ALSO, WHERE DO THE PRECIPITATION BOUNDRIES SET UP?  IT CAN ALL CHANGE SO STAY TUNED.  THIS IS JUST ONE PIECE OF DATA.  HOWEVER, THERE ARE MANY OTHER SHOWING ALMOST THE SAME THING.

3 comments:

Anonymous said...

When do you think this will start Monday? As of right now, what's your best estimate? Noon? Later?

Anonymous said...

No love for Jonesboro? :(

Anonymous said...

Todd, just wanted to say what a terrific resource your blog is and the effort you put into it is much appreciated. I've always been fascinated by the weather and you do a terrific job explaining the data you use and some of how you use it to make your forecasts. Keep up the great work!