Tuesday, March 08, 2011

Tuesday Trouble

The name of the blog post is probably a little overdone, but who doesn't like alliteration?  There are a few main reasons the storm system today and tonight will not be a huge severe weather producer.  First, the main risk for severe weather will be coming in at night which will help limit instability.  While things will destabilize, it would be worse if this came in 6-8 hours earlier with complete sunshine during the heating of the day.  The other limiting factor will be the lack of significant moisture.  The deep moisture severe thunderstorms thrive on will stay across Texas and Louisiana.  Moisture for thunderstorms is like the gas that fuels your car (but much cheaper LOL).  You need dew points 55 degrees or higher to see significant amounts of severe weather.

Now I don't want to totally down play what will happen tonight because there will be the potential for hail and wind and I'm fairly sure there will be severe thunderstorm warnings issued.  The warm front will move northward tonight and we will have to watch for a small chance for an isolated tornado, mainly across southern Arkansas.  While I think the real threat for that should stay south of the state, you must always watch it closely.

The entire state is under a slight risk for severe weather.  I'll post those maps from the Storm Prediction Center at the very bottom of this post.  Also, what your will see below are maps taking you step by step through the system moving through.  It's the high resolution WRF model from the National Severe Storms Laboratory.  They will show simulated radar while the arrows show which direction the surface winds are coming from.   The longer the arrow, the higher the wind speed from that particular direction.  Remember, this is just a model I'm going to show and we'll watch and see how good it is during the event.

Noon.  Scattered showers and storms moving across the state.  Nothing big with surface winds out of the southeast.

3 PM in the afternoon shows thunderstorms with areas of light to moderate rain across the state.
By 6 PM we will continue to have light to moderate areas of rainfall.  Notice the storms now firing up along the dry line in northern Texas into eastern Oklahoma.  Keep an eye on these storms as they move across the state tonight.  Surface winds are still out of the southeast. Notice winds in central OK coming out of the northwest.  This is behind the cold front.
By 8 PM strong to possibly severe storms will be moving out of Oklahoma into western Arkansas.  Surface winds are still out of the south and southeast.  Slightly stronger northwesterly winds are seen behind the storms as the cold front advances eastward.
One hour later at 9 PM, the storms are moving into western Arkansas with the threat for some hail and high winds.  Heavy rainfall looks like a good bet as well.  There are areas of heavy rain in central AR as well.
By 10 PM, the cold front is now in western AR with storms along and ahead of it from NE Texas to SW Arkansas.  The further north you go, the main threat is heavy rain.
By 11 PM the heavy rain and storms are moving into central Arkansas.  The cold front is now knocking on our door.
By midnight, it's a soaker in central and southern Arkansas.  There will be some wind and hail possible as well.  Remember, we can't rule out an isolated tornado, especially across the south.  Things should be drying out across western Arkansas
By 1 AM, the heaviest of the rain could be getting ready to leave Little Rock.  Westerly winds behind the front will begin to dry and stabilize our atmosphere.
By 3 AM, things are really beginning to wind down in central Arkansas with moderate to heavy rain for southern and eastern areas.
Slight risk for severe weather for most of the state later today from the Storm Prediction Center
15% for severe hail for most of the state.

15% for severe winds for much of the state.
Small risk for tornadoes with the highest risk for Louisiana.

1 comment:

jimmylee42 said...

Still looking to see if we get another freeze at either LR or NLR. IF we don't, according to the NWS records we will set records at both locations for earliest late freezes.

My little bucket out in St. Charles WLR measures 1.3 inches of rain for this last rain event. Congrats to both of UALR's basketball teams for winning their championships and a spot in the big dance.