198 
FXUS64 KTSA 161657
AFDTSA

Area Forecast Discussion
National Weather Service Tulsa OK
1157 AM CDT Sat Oct 16 2021

.DISCUSSION...

The 18Z TAF forecast discussion follows...

&&

.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
VFR conditions will prevail today as high pressure builds into the
region. NW winds may occasionally gust over 12 kts across far NW 
AR. Light and var winds tonight with some potential for light MVFR
fog at KFYV and KFSM.

&&

.PREV DISCUSSION... /Issued 944 AM CDT Sat Oct 16 2021/ 

DISCUSSION...

Northwest flow aloft prevails over the Plains in the wake of a
progressive shortwave trough over the Ohio Valley. At the surface,
a broad anticyclone stretches from the Great Basin and central
Rockies east into the central and southern Plains. Some valley fog
over NW AR and neighboring NE OK is burning off quickly as daytime
heating continues. The cold front which moved thru yesterday 
stretched from northern NY south and west into the western Gulf. 
Expect a Chamber of Commerce day across the region in the wake of 
the front. Highs should top out in the upper 60s to low 70s under 
full insolation. No noticeable changes were made to the going 
forecast for the morning update.

PREV DISCUSSION... /Issued 317 AM CDT Sat Oct 16 2021/ 

DISCUSSION...
Nighttime fog imagery shows some valley fog has developed across
portions of northwest Arkansas and far eastern Oklahoma. Will need
to carry patchy fog for an hour or so after sunrise. Otherwise,
expect a very autumn-like day across the region as a surface ridge
gradually works east across the area and mid level heights rise
as a shortwave ridge approaches from the west. Winds will be 
noticeably calmer than on Friday and remain generally out of the 
northwest. Temperatures will stay a few degrees below seasonal 
value today but warm back to near normal on Sunday as southerly
flow returns and the ridge axis moves across the High Plains.
Expect another cool night tonight as dry air settles into place
and mostly clear skies and light winds continue. 

Afternoon highs will stay in the mid 70s through mid week with
overnight lows returning back into the 50s for most locations by
Tuesday. Southerly winds will strengthen with time early next week
as a lee side trough develops in response to a storm system moving
across the Rockies and into the Plains by early Wednesday. While
moisture return ahead of the system will likely be stunted, a
narrow tongue of higher dewpoints is expected to advect north into
central Oklahoma and eventually the northeast part of the state as
lift from the approaching system and associated cold front moves
into the area. Agreement between the deterministic solutions with
support from their respective ensembles provides enough confidence
to continue slight chance PoPs Wednesday into Wednesday night. Did
note that the GFS and Canadian members did show lower
probabilities than the previous run so don't expect showers and 
storms to be too widespread. Have also reinserted low PoPs late 
Tuesday night based on similar agreement in the latest guidance
showing the onset a bit earlier. Solutions diverge by the end of 
next week with the GFS and Canadian holding on to some showers 
across parts of far southern Oklahoma as they develop a more 
energetic northwest flow from the western High Plains into 
Arkansas during this time with the frontal boundary holding to our
south. At this time expect Wednesday's front to bring modest 
cooling with temperatures returning back to near seasonal levels 
by week's end.

&&

$$

Lacy