Friday, February 28, 2014

Major Battle Sunday. Winter vs. Spring


10:40 AM Friday Update... New video going over the newest data.  The AM run of the GFS is looking closer to the colder NAM.  This forecast can still change!  This video also goes into specifics for Marathon runners.  Please read the post below the video for even more specific information.



This is the last day of the winter weather contest.  Check out the latest numbers this morning (Friday).  Click on the contest in the navigation bar above.

Sunday will be one of those days that will have you saying "Never Say Never To Arkansas Weather".  There could be winter storm warnings across the north and a severe weather potential across the south.  Where do I begin?

First of all, this is a system I have been following on the blog for several days now and I said the models had major disagreements.  Those disagreements are still there!  The BIG questions: where does the front end up, where does the wave of low pressure track, and how intense is the cold air behind the front?

I preach this over and over and over...  cold, arctic air is stronger and faster than the models forecast 99 out of 100 times.

At this time, it appears there is a good chance the front is just north of Little Rock at 6AM Sunday, but surges south during the morning.  However, there are a couple models which hang it up over central Arkansas for awhile. The wave of energy will be strong and I expect strong to even severe thunderstorms to develop within the warm sector over Louisiana and maybe even far southern Arkansas.  The Storm Prediction Center has placed that section of the state in a "slight risk" for severe weather.  Further north, the cold air will be very shallow.  I expect elevated thunderstorms to develop.  There's a chance rumbles of thunder will be heard with heavy amounts of freezing rain and/or sleet across the north.  The convective nature of the system COULD increase ice amounts in that location.

Below are maps from weatherbell.com

No guessing where the front is located.  The front is just north of the metro at 6 AM according to the Canadian model.
The European at 6AM keeps the front confined over northern AR with frontal passage in central AR later in the day.  It's mild at 6AM with temps in the 60s with this model
The GFS at 6AM indicates the front is located directly on top of Little Rock with readings in the 40s.
The NAM shows the front just north of the metro at 6AM with temperatures near 60.

Now let's advance 6 hours later to Noon.  First, I wanted to point out, according to MOST of the data, the front is north of Little Rock at 6AM and it's mild here.  With that said, I would NOT be surprised to see it further south due to the nature of arctic air.  It arrives faster and stronger.  So we MUST keep an eye on this.

By Noon, the front is in southern AR according to the Canadian.  It's in the low 40s here in central AR.
At Noon, the European keeps the metro in the warm sector with temperatures in the 60s still.

The GFS at noon continues to stall the front right over the metro
The NAM looks like the Canadian with the front well south of the metro and temperatures in the 30s.  Look at the HUGE contrast from NW AR to SE AR!!!!!
Now onto precipitation according to the GFS overnight run. Remember, this shows you precip amounts over the previous 6 hours.  Green is rain, purple is freezing rain, orange is sleet, and blue is snow.

Saturday night into Sunday morning, some light precip is breaking out over the state with the frozen stuff up north.
During the morning, 6AM to Noon, precip and storms really pick up in intensity.  The frozen precip is still north.
During the afternoon, a cold rain continues across much of the northern half of the state with ice north.
The surface wave pulls off to the east and the cold air gets drawn in from the north sending the freezing line south into central AR by midnight Monday AM changing the rain to an icy mix
The system pulls rapidly to the east and it's over early Monday AM with very cold and VERY windy conditions.  The black lines are isobars, lines of equal barometric pressure.  The closer they are, the windier it is!  Hold on to your hats.  This will cause problems IF there's icing in the trees across northern Arkansas.
The Storm Prediction Center has placed southern AR in a slight risk for severe weather.  General thunderstorms in the green so some of the ice will be convective up north.
IN SUMMARY, IT'S GOING TO BE A MESS ACROSS THE STATE FROM STORMS TO ICE AND A HUGE RANGE IN TEMPERATURES SUNDAY.  WHERE THAT FRONT IS LOCATED IS STILL A BIG QUESTION IN MY OPINION.   IF I HAD TO PLACE BETS ON IT IN VEGAS, I WOULD SAY IT'S FURTHER SOUTH THAN THE MODELS SUGGEST BASED ON HISTORY.   STAY TUNED!

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