A serious drop in visibility at Jonesboro!

[Scott Dennstaedt, PhD]

So what the hell is going on in Jonesboro, Arkansas?  Vis of 10SM ends up dropping off to 1/2SM and then dropping to less than 1/4SM.  No significant weather occurring at the airport.

KJBR 092219Z AUTO VRB04KT 10SM SCT029 BKN037 29/22 A2994 RMK AO2 
KJBR 092207Z AUTO 22005KT 10SM BKN029 OVC035 29/22 A2995 RMK AO2 
KJBR 092153Z AUTO 00000KT 10SM SCT029 BKN035 29/23 A2995 RMK AO2 SLP138 
KJBR 092130Z AUTO 21003KT 10SM FEW027 29/22 A2996 RMK AO2 T02940222 
KJBR 092122Z AUTO 23006KT 10SM BKN027 BKN034 30/22 A2996 RMK AO2 
KJBR 092108Z AUTO 25004KT 3SM HZ SCT027 30/22 A2996 RMK AO2 
KJBR 092106Z AUTO 26006KT 1/2SM HZ SCT027 30/22 A2996 RMK AO2 
KJBR 092053Z AUTO VRB03KT M1/4SM HZ BKN027 30/22 A2996 RMK AO2 SLP143
KJBR 092040Z AUTO 33005KT 4SM HZ BKN023 BKN029 31/23 A2997 RMK AO2 
KJBR 092037Z AUTO VRB04KT 3/4SM HZ OVC025 30/22 A2997 RMK AO2 
KJBR 092025Z AUTO 29006KT 1/4SM HZ BKN023 OVC029 29/22 A2997 RMK AO2 VIS M1/4V5 
KJBR 092018Z AUTO 29007KT 1/2SM HZ BKN023 OVC029 30/23 A2998 RMK AO2 
KJBR 091953Z AUTO 33006KT 10SM BKN022 OVC029 29/23 A2998 RMK AO2 SLP150 
KJBR 091853Z AUTO 26005KT 10SM BKN021 28/22 A3001 RMK AO2 SLP159 
KJBR 091753Z AUTO 24008KT 10SM BKN017 28/23 A3002 RMK AO2 SLP163 

Edited June 10, 2021 by Scott Dennstaedt, PhD

[hammdo]

Dust (though winds are lite), or smoke from a fire would be my guess - not much pollution in that area unless there is a lot of new factories there... maybe a humid day could also cause hazing - I'll need to see if a large lake is near by...

-Don

[StevenL757]

I’d tend to agree.  Temp and DP spread aren’t conducive to fog formation to create those sporadic low levels of visibility.

[Tony Starke]

Maybe smoke or smog being trapped by a temp inversion?

[Scott Dennstaedt, PhD]

1 hour ago, Tony Starke said:

Maybe smoke or smog being trapped by a temp inversion?

Pretty likely.  

There's a hell of a lot of smoke across much of the Lower 48 -- and over AR in particular.  Increased haziness becomes highlighted later in the day (as the sun-satellite geometry creates more forward scattering from aerosols as you can see in this image as a pale brown color):

The period of light winds probably allowed smoke to subside within the boundary layer and reach the surface -- surrounding areas with convection likely had enough wind to ventilate the surface and keep the vis higher during some of the time.
 

Edited June 10, 2021 by Scott Dennstaedt, PhD

[Scott Dennstaedt, PhD]

1 hour ago, StevenL757 said:

I’d tend to agree.  Temp and DP spread aren’t conducive to fog formation to create those sporadic low levels of visibility.

Turns out that the obstruction to vis (e.g., FG, BR, HZ) placed in an ASOS report is highly dependent on the dewpoint depression as I discuss here.