Severe Weather and Flooding

It's here!  The much talked about storm system will arrive today and it will not leave until Thursday PM.

This video goes over:

• SPECIFIC THREATS
• TIMING
• LOCATION OF THOSE THREATS
• HOW MUCH RAIN MAY FALL
• A SECOND ROUND OF SEVERE STORMS POSSIBLE THURSDAY

Wednesday Worries

Worries?   I guess I should become a writer for network news.  How many times have you heard national anchors say, "why you and your family should worry about________"?  It gets old doesn't it and now I use it.  HOWEVER, there's also a chance this severe threat will not be too great!

As with most storm systems, there are always questions that really can't be answered until we get within 12-24 hours of an event and sometimes not until just before storms begin to fire up.  We'll need to watch morning rain and storms.  This would act to limit daytime instability and lessen the severe weather threat.  With that said, if we break out into sunshine, then we all know that adds fuel to the fire and storms can get out of hand.

Beyond this severe weather threat, we'll have ANOTHER chance for a frost/freeze next weekend.  More on that later.

Most of the following maps are from Weatherbell.com

1PM cloud cover indicates there should be quite a bit Wednesday.  This COULD help to limit the instability.

Late Wednesday instability (CAPE) should be highest across western, southern, and portions of central Arkansas.  This is where the SPC has the risk for some severe weather.

1PM temperatures Wednesday.  Look at the pockets of cool over the north and northeast.  Again, that could help lessen the severe weather threat there, but look at the warming south and west early in the afternoon.

Lifted Index (LI) is another parameter we often look at for instability.  The more negative the number is, the more unstable the atmosphere.  The over night run of the GFS points towards eastern OK and southern Arkansas Wednesday afternoon.  Remember, we are 2 days away and much of this can still change.

Storms, Easter, and April Fools Chill

We have a lot to talk about over the next 2 weeks.   This video goes over everything in detail from A to Z.

• EXACT timing of storms tonight and specific threats
• Easter sunrise weather
• Possible late Easter rain and storms.  I am not ruling out some hail
• Early April chill
• Possible comparison to April 2007.... POSSIBLE 

Winter Contest Winner

Total snow for Little Rock, North Little Rock, Harrison, and Pine Bluff = 20.2''

Playing the "Price Is Right" rules.  The person closest without going over guesses 20.1''.  Congratulations to...

JIM CRAIG

It's Going To Get Rough Today

The much talked about (for well more than 1 week) "bowling ball low" will barrel through the state this afternoon and evening.  My thoughts have really not changed as to how this evolves.   As you always know, mother nature can throw curveballs and I'm always aware of that possibility.  Hail will be the big concern today, but there's also a threat for tornadoes.  I don't think it's a big threat, but it is there.  Also, it will NOT take severe winds to topple trees due to the very saturated ground.  I expect a few power outages.

The Storm Prediction Center has upgraded much of the area from a "slight" to "enhanced" risk for severe weather.  What does that mean?

• SLIGHT- Scattered severe storms possible.  Short lived and/or not widespread isolated intense storms possible.  1-2 tornadoes possible along with some reports of damaging winds and hail 1-2'' in diameter.
• ENHANCED - Numerous severe storms possible.  More persistent and/or widespread, a few intense.  A few tornadoes possible with several wind damage reports.  Hail 1-2'' in diameter.

The following maps are an hour by hour look at simulated radar from the HRRR (High Resolution Rapid Refresh).  Again, this will not be perfect, but it does give a good general idea.

While there will be hail, not everyone will see severe hail.  HOWEVER, it would be appropriate to find some protection for your car or whatever can be damaged from large hail.  You should have plenty of advance warning by watching radar today.

Sunday Severe Update

The system we have been discussing on the Arkansas Weather Blog for more than a week will swing through the state Sunday afternoon and evening.  There's plenty of cold air aloft and that will be favorable for hail production.  In these situations, an isolated tornado or two can't be ruled out, but the threat is low.  It's a fast moving system and I expect it to be east of the Mississippi River by midnight tomorrow.

Not everyone will have a thunderstorm Sunday because they will be widely scattered, but if you get under the core of one of these storms, you run the risk for large hail.  Below are the threats and specific timing.

BTW, I'll have final numbers for the winter weather contest very soon.

Also, we're going to dry out next week and enjoy warm weather, but I see colder air returning by the end of next week.  Remember, it's still technically winter.  I'll blog about that later.

MOST OF THE FOLLOWING MAPS ARE FROM WEATHERBELL.COM.

THIS IS SIMULATED RADAR FROM THE 4KM NAM.  IT WILL !NOT! BE PERFECT, BUT GIVES YOU A GOOD GENERAL IDEA.

4PM SUNDAY

5PM SUNDAY

6PM SUNDAY

7PM SUNDAY

11PM SUNDAY

1AM MONDAY

SEVERE RISK SUNDAY FROM SPC

SPECIFIC THREAT LEVELS

Sunday Severe

A new and completely different storm system will follow quickly on the heels of the one we're dealing with now.  As I have discussed here on the blog for more than a week, the main threat will be large hail.  I can't rule out a tornado or two out of this storm system.  This will likely all happen Sunday afternoon and evening.  It's a quick moving storm system which will help limit any additional flooding concerns, but it won't take much to cause more problems.

This video goes over everything you need to know from A to Z.  Some of these maps are courtesy of weatherbell.com

Hail of A Storm

Last week, we saw it coming.  The only questions needing an answer, how much and exact location?  At first, we thought right through southwest into northeast Arkansas, then all the data shifted northwest a bit.  Then as we got closer to the event, it all went into the southeast 1/2 of the state.  This is what we mean when we can't give specifics far in advance.  We knew heavy rain was likely, but until you get within 1-2 days of the event, you don't know specifics. 

Amounts of more than 1 foot are reported across southeast Arkansas as of early Thursday morning and we still have a day or two of this left.  However, the intensity should begin to diminish soon.  Nevertheless, the damage has been done and we are completely saturated and flooded.  Any additional rain will cause problems.

If you have been following on Facebook or Twitter, I have been talking about another storm system which will follow quickly on the heels of the one on top of us.  This was also discussed last week.  This is what I call a "bowling ball" low.  It's a very compact area of low pressure aloft.  The air above our heads will be very cold and will help contribute to destabilization of the atmosphere.  I expect this to arrive Sunday afternoon and evening.  Showers and storms will become likely.  Some of those storms may become severe.  Due to the cold air aloft, severe hail is the main threat.  Can I rule tornadoes out?  No, However, that threat is low, but it is there.

Is winter over?  NO!  While I can't promise winter weather, it will get cold again later this month.  Once again, it's too far away for specifics, but it's on the radar.  Pun intended.

Viewer rainfall totals are highest over the southeast corner of the state.  As I write this (9:30AM Thursday, March 10th), a rare FLASH FLOOD EMERGENCY has been issued for Ashley and Chicot counties in southeast Arkansas with more than a foot of rain over the past 2 days and 2-4'' more possible.

This is the upper level flow at 500mb showing the intense, but small area of low pressure moving through Sunday afternoon and evening.  This will lead to areas of rain and storms with hail the main threat.  Can this cause additional flooding?  Yes, but additional amounts will not be anything like we have seen over the past 2 days due to the quick moving nature of this storm system.

The Storm Prediction Center has already outlined much of the southern half of the state, including the metro for a severe weather threat Sunday.

Rain, Rain, Then After That, More Rain.

The much talked about rain is almost here.  This is going to be a typical spring soaker and these can cause problems.  As mentioned last week, the rain will come in waves spread out over 2-4 days.  This will help reduce the flash flooding threat since it should not all come at once.  With that said, there will be significant enough rainfall and flash flooding will still be an issue.  Remember, turn around, don't drown.

River flooding will become an issue this week and beyond.  As far as severe weather is concerned, there will be a very low threat south and west later Tuesday.  It would not surprise me to see a couple strong to maybe severe storms, but again that threat is low.

How much rain and where?  If you read my previous blog posts, you know that's something we have been trying to pin down.  The axis of heaviest rainfall should be located across western and central Arkansas or roughly the western half of the state.  I think amounts of 5-7'' through Saturday will be a good bet with isolated higher amounts.  The further east you live, the amounts should decrease with a sharp rainfall total gradient setting up over that portion of the state.  That simply means there will be a short distance between high rainfall totals and lower amounts.

Once again, I want to discuss the "what ifs".  With a well advertised storm system like this seen on the models well in advance, you have to always think of what could go wrong with your forecast.  The exact location of the heaviest rainfall could be misplaced a bit, but probably not by much.   Also, something I have talked about since last week.  If a big cluster of thunderstorms develops along the Gulf coast or Louisiana, this can rob moisture from advancing north and decrease rain totals significantly.  While that scenario is possible, at this point, it's unlikely to happen.  Remember, it's something I'll be watching as the event unfolds.

I have had some tell me the word "biblical" rains are coming.  I do not know where that is coming from and I never said that.  If this event seems "hyped" it's only because the models have seen this for many days and I have tried to stay on top of it as much as possible.  My goal is not to hype, but communicate the threats effectively.  My goal is to pin down this forecast to the best of my ability.  This will be a significant rain event, but this is not going to be something we have not seen before in the past.  We get heavy rain events this time of year! 

Here are daily rainfall records for Little Rock.  Some of these might be challenged.

• Tuesday March 8th, 1.97'' set in 1990
• Wednesday March 9th, 4.32'' set in 1878
• Thursday March 10th, 2.02'' set in 1903
• Friday March 11th, 2.68'' set in 1921

This is called a meteogram.  It goes out in time from left to right.  You can see that blue bar showing the period of the heaviest rain according to the GFS late Wednesday.  This model gives Little Rock 10'' with this particular run.  At this time, I'm going 5-7'' with isolated higher amounts.   Remember, this model is run 4 times a day and comes up with 4 different amounts.

The GFS through Thursday morning shows significant rainfall for much of the metro with higher amounts southwest and lesser amounts east.

As of Tuesday morning, a flash flood watch is in effect for most of the Channel 7 viewing area.

This is our updated Tuesday morning rainfall forecast Tuesday through Saturday.  I do think there could be amounts over western and southwestern Arkansas between 7 and 10'' over a 4 day period.

Doggone Wet and You'll Need "Oliver" Rain Gear

I had a little fun with our dog in this blog video.  This video is loaded with specific timing and threats as we see a very wet and unsettled weather pattern evolve.

• When does it arrive
• The main threats from the rain
• How much and where
• What time period is favored for the most rainfall
• When will it end.

Spring Soaker Or Are Models Nothing But Jokers?

All of the models are sending us a strong signal for a major rain event next week (Tuesday - Friday) along with some severe weather.  So is it a done deal?  To quote the great Lee Corso, "not so fast my friend."  While it's definitely within the realm of possibility with almost unanimous support from all the guidance we use, I have seen these situations head south.  Pun intended!

I was talking to meteorologist Ryan Vaughan at our sister station, KAIT, in Jonesboro.   We both agree how odd it is all the models show so much rain.  I start thinking what could go wrong?  As meteorologists, we see things like this coming, and then all of the sudden something happens and people are left asking, "where is all that rain you forecast?"  Once again, it's hard to ignore all the data and all the data shows heavy rainfall along an axis oriented from southwest to northeast.  At this time, the highest chance for that heaviest rain axis will be along the I-30 to 67/167 corridor eastward with lesser amounts northwest.

So what could go wrong?  A couple things.  What if the axis of heaviest rainfall sets up east of the state?  What if it backs further to the west.  The latter seems to be very unlikely.  One other consideration, what if a large area of thunderstorms along the Gulf coast robs the significant moisture from moving into Arkansas so instead of 6'' +, it's much less.

Once again, ALL of the models show the real distinct possibility for flooding rainfall, but I want to use this blog to let you know what the "what ifs " are at this point.  It would be wise at this time to prepare for heavy rainfall and even some severe weather.  I'll keep you updated here, social media, and on Channel 7.

Models below are courtesy of Weatherbell.com

Here are the last 4 runs of the GFS and this helps to illustrate one of my points.   Where does the axis of heaviest rainfall set up?  You can see it's shifting a little with each run.  BTW, that purple area is 10'' plus!  AS I ALWAYS SAY, THESE ARE MODELS AND NOT FORECASTS.  So now you see our concern for a very heavy rain event.  The models show the most likely area will be along and east of the I-30/67-167 corridor with lesser amounts northwest.  As we get closer to next Tuesday and Wednesday, we'll fine tune the forecast and hope it's not this much rain!!!!

I

Marching Into Unsettled Weather

Video blog loaded with good information on the following...

• TORNADO SIREN RANT
• STORMS/RAIN TONIGHT INTO THURSDAY MORNING
• HEAVY RAIN/SEVERE THREAT NEXT WEEK.