Thursday, June 22, 2017

Cindy... To The Point

*Thursday will not be a wash-out.  

*Expect scattered showers and storms to develop, especially this afternoon 
 
*There's a very low chance that a storm could produce a brief tornado or two this afternoon and evening across mainly southern Arkansas, but the chance is on the low end.

 
*Heavy rainfall will be likely tonight into early tomorrow morning for areas south and east of Little Rock


*Gusty winds across southern and eastern Arkansas may cause a few power outages.
 
*A flash flood watch is in effect for those areas south and east of the metro for 2-4'' of rainfall with locally higher amounts.

 
*Some areas north and west of the metro will see little if any rainfall 

 
*Friday should NOT be a wash-out.

 
*Rain will taper off from west to east during Friday morning

 
*We'll receive a break in the rain Friday late morning into the afternoon

 
*A front will move into Arkansas from the north Friday afternoon and evening

 
*Scattered showers and storms will redevelop later Friday

 
*Some could be strong to severe, but the chance is low

 
*MUCH cooler and drier air begins to arrive this weekend.


The following maps are from the 3KM NAM off of Weatherbell.com.  It's simulated radar and it's never perfect, but has a fairly good handle on the situation.

6PM Thursday.  Scattered showers and storms with locally heavy rainfall likely.  There's a low chance of a brief and isolated tornado.
Midnight Friday morning shows the heavy rain in southern Arkansas.


6AM Friday... heavy rainfall over eastern and southern Arkansas.


By noon Friday, the heaviest of the rain is crossing over the Mississippi River.  The chance for rain will decrease and a break is likely.
A new front will run into unstable air by late Friday afternoon into the evening.  This is 6PM.  Scattered showers and storms could be strong.
Flash flood watch east and south of the metro for 2-4'' of rainfall with isolated higher amounts.
Slight risk for severe weather southeastern Arkansas later today. The main threat will be strong winds and a brief tornado or two
Euro rain totals guidance. Heaviest south and east with little north and west.  Notice the strong rainfall total gradient!

Wednesday, June 21, 2017

Wednesday Afternoon Cindy Update

There are two noticeable things I really want to point out when it comes to the remnants of Tropical Storm Cindy moving across Arkansas.

1.  THIS WILL MOVE THROUGH FAIRLY QUICKLY WITH THE HEAVIEST RAINFALL THURSDAY NIGHT INTO EARLY FRIDAY MORNING


2.  THERE WILL BE A SIGNIFICANT RAINFALL GRADIENT MEANING RAINFALL AMOUNTS WILL GREATLY VARY OVER A SHORT DISTANCE.

The overall speed of the system may be quicker than first anticipated meaning Friday afternoon COULD turn out to be nice for some!  The heaviest of the rainfall should be south and east of the Little Rock metro area with 2-4'' common.  There MIGHT be isolated higher amounts.

What about severe weather?  That threat will be low, but an isolated tornado or two can't be ruled out Thursday afternoon into the evening, especially over southeastern Arkansas.

The following maps are the 3KM NAM from weatherbell.com.  This is future radar and it is NEVER perfect, but this may have a good handle on the situation.  Again, look at how some areas get heavy rain, but some may get little if any across western and northern Arkansas.

Also, the last map is the European from EuroWX.com showing total rainfall.

3PM Thursday.  There could be a rain band or two moving through the state.  Any storms in these bands could briefly rotate.

7PM Thursday

1AM Friday.  Look at that rainfall gradient!  Heavy rainfall south  and east with little north and west.

4AM Friday.  Areas south and east of the metro getting heavy rain.

By 8AM, the back edge is already leaving!

From EuroWx.com.  There's a HUGE rainfall gradient.  From .25'' in the River Valley to 1-2'' central.  Look at eastern and southern Arkansas!  2-4'' look common with isolated higher amounts according to this model.


Cindy Update

The track of Cindy means everything.  It's surrounding the track and areas south and east that stand the highest chance for heavy rainfall and there could be localized flooding.  At this time, it appears 2-4+ inches will be likely with isolated higher amounts.

I also expect a very strong rainfall gradient. This means the rainfall amounts will change greatly over a short distance.  There might be cases where one portion of a county sees more than 2'' and the other end only receives .5''.  At this time it appears that gradient will set up somewhere along the I-30 to highway 67/167 corridor.

There's also the threat for some severe weather Thursday mainly across southeast Arkansas.  Gusty winds and an isolated, brief tornado or two will be possible.

Scattered showers will likely increase Thursday.  The rains around tropical systems typically contract at night and surround the center.  During the day, it expands and affects a larger areas.  Some of the data suggests an area of very heavy rain Thursday night in the Arklatex, then it expands to cover up a much larger area Friday.  That's when the greatest chance for rain will exist.  The system should exit late Friday and that faster movement may help prevent higher amounts.

This is the early morning track from the NHC.  It's surrounding this track and south and east of it that have the highest chance for heavy rainfall.

3AM Friday morning, 1 computer model shows this system entering the Arklatex.  Many times, the rainfall at night contracts around the center and it looks like this model is keying in on that.  Heavy rain possible SW at that time.
Just a few hours later, the rainfall expands and affects more of the state.  Some of it heavy.


The European model continues to show the heaviest across the SE 1/2 of Arkansas.  Notice the rainfall gradient.  North and west of the metro .5'' or LESS while south and east of the metro could see at least 2-4''.

The overnight run of the GFS shows basically the same thing with a very tight rainfall gradient with 2-4'' + across south and east Arkansas.


The NAM also shows that gradient.  Look at Perry and Faulkner counties.  Amounts light there, but heavy near Little Rock to Pine Bluff and Sheridan.

There will be a slight risk for severe weather to the right of the track across southeast Arkansas.
If there are tornadoes, they are usually brief and weak.  This will need to be monitored.