Friday, October 10, 2014

Severe Weather Chances Increasing



October is becoming more active than spring, if you take out that one storm which produce the devastating Mayflower/Vilonia tornado.  For all of April and May, the North Little Rock National Weather Service office issued 119 severe thunderstorm warnings.  Just in the first few days of October, we're up to 39.  By Monday afternoon, we may not exceed 119, but we're going to inch higher.  The idea this would be an active severe weather season is unfortunately becoming a reality.

Heavy rain will be the main threat late Friday into Saturday as a slow moving cold front interacts with copious amounts of moisture including moisture from the Pacific hurricane, "Simon".  The front will settle across southern Arkansas Saturday allowing very cool air to filter into the state.  We're not getting out of the 50s and 60s for much of central and northern Arkansas.  By Sunday, the front will begin to move to the north in response to a developing storm system to our west.  While there will be a small chance for rain/storms Sunday, the best chance arrives Sunday night into Monday.  The timing of this can still change and that's going to play a key role as to the severity of the storms Monday.  If the storm is delayed and comes through Monday afternoon, that will only allow the instability levels to increase and the severe weather threat will be greater.  Even if it comes through during the morning, severe weather will be possible.

At this time, hail and wind will be a major concern.  Isolated tornadoes can't be ruled out, especially if any thunderstorm can develop ahead of the main line.  I can't stress this enough, this can still change and I urge you to keep checking back.

By Tuesday, we should begin a stretch of cool and dry weather.

Much of the model data below is courtesy of weatherbell.com

This is only 1 model, but let's see what it says.  By 4AM Monday, rain and storms will be ongoing across the north.  Watch the line of storms develop rapidly over Oklahoma, then push over to Arkansas.
By 7AM, you see the line crossing from OK into AR.  See those storms ahead of the main line?  Don't take this literally as each model run will change, but if any storm can develop ahead of the main line, the tornado threat will increase.  Also, if this system slows down, that only allows daytime heating to add fuel to the fire.
By 10AM, The line is marching east and affecting central Arkansas.  There are times when the line moves much faster than the models predict.
By 1PM, the line is getting ready to cross the MS River.
The Storm Prediction Center already shows a "Slight Risk" for severe weather later Sunday.
On Monday, much of the Channel 7 viewing area has a risk for some severe weather.  At this time the main threats will be wind and hail.  A tornado threat will increase, especially if any storms develop ahead of the main line.
Rainfall amounts will range between 3-5 inches or more over the next 5 days.

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