Saturday, April 18, 2015

Severe Potential Sunday

While not a huge outbreak, I do expect strong to severe thunderstorms Sunday afternoon and evening.  Much cooler and drier air will move in Monday.

This video goes over specific timing and threats.

Friday, April 17, 2015

Severe Weather Threat Late Sunday

Did I talk too soon?  A few days ago, it looked like the chance for any organized, widespread severe weather was shut down for awhile.  While I don't expect this to be widespread, we will have a few hours late Sunday afternoon and early evening we need to watch for strong to severe thunderstorms.  This looks more "linear".  With a line of storms, the tornado threat is there, but it's low.  The main threat will be wind and hail with the line.

This is the transition to a much cooler weather pattern.  At this time, I have highs Monday and Tuesday at 70 degrees with lows in the 40s and 50s.  It would not surprise me to have highs only in the 60s.  NOAA released their 6-10 and 8-14 day outlook and it has temperatures below average and precipitation above average.

The model maps below are from WeatherBell Analytics.

The timing of this will not be perfect, but this is what we're expecting at this point.  Remember, as this evolves, things can change.  Look for a line of storms to develop late Sunday afternoon and evening.  This is simulated radar at 7PM Sunday.
This is CAPE (Convective Available Potential Energy) Sunday at 7PM.  This is the instability, the fuel for thunderstorms.  The levels are above 3000 for some locations which is plenty for strong to severe weather.
By 10PM, the line is past the metro and moving into south central and east central Arkansas.
By 1AM Monday, the line is across southeast Arkansas and getting ready to cross the Mississippi River.
The Storm Prediction Center has outlined much of Arkansas in an area with the greatest threat for severe weather.  This is all late Sunday with the line we're expecting to develop.
We'll have a medium threat for wind and hail, which is typical with a line of storms.  The tornado threat is there, but is low.  This is still subject to change.
The NOAA 6-10 day outlook indicates a good chance for below average temperatures.
It doesn't change in the 8-14 day outlook.  The average high is well into the 70s, but should be below average for awhile.

Monday, April 13, 2015

Widespread Severe Weather Shut Down For Awhile

And that's a very, very good thing!  You can NEVER rule out a strong to severe thunderstorm this time of year, but widespread severe weather does not look likely over the next couple weeks for our portion of the country.  That takes us into the end of April.  Once we get towards mid to late May, our primary severe weather season begins to fade away.  I do not think we'll escape this spring, but I hope we keep the activity to a minimum.

The bigger weather story this week will be the periods of rainfall we're expecting, then the big weather story will turn to well below average temperatures.

We'll have rain increase today (Monday), then the showers will become more scattered Tuesday and Wednesday.  The chance for rain may increase again by the end of the week as a new storm system approaches.  The exact timing and location will be difficult to pin down this far in advance, but it does look unsettled.  Again, the chance for severe weather is there, but it looks very low for awhile.

As we go into next week, the pattern really begins to amplify.  That means the jet stream will have substantial troughs and ridges.  One of those ridges will go up over western Canada with a downstream trough.  You know what that means?  That ridge will deliver a surge of cold air to the south and temperatures may go well below average next week.

5 day rainfall totals will be significant.  Since this is spread out over the entire week, flooding concerns are not too high at this time.  However, you see how active the weather will become.
By next Tuesday, April 21st, you can see the ridge poking up into western Canada and a strong trough developing over the central United States.  This will put a big dent in any widespread severe weather chances and keep it cooler than average.
NOAA's 8-14 day outlook indicates a good chance for below average temperatures.  Notice where the above average temperatures will be located... underneath that ridge!