Flood and Damaging Winds in Kansas, August 7 to 8, 2021

Area Forecast Discussion
National Weather Service Wichita KS
640 PM CDT Sat Aug 7 2021

.SHORT TERM...(This evening through Tuesday)
Issued at 255 PM CDT Sat Aug 7 2021

Forecast highlights the next 7 days:

* Thunderstorm potential this evening through Sunday evening, and
  again Tuesday afternoon-night.

* Hot above normal temperatures through about Thursday of next week.

An unseasonably strong/deep upper shortwave and an associated
surface trough all approaching from the west will be the focus for
scattered thunderstorm development and maintenance this evening
through tonight across the region. Analysis of model soundings
suggest warmer mid-level temperatures and associated capping issues
further south will likely keep the higher thunderstorm probabilities
generally along and north of Highway 56 across central, north-
central, east-central, and northeast Kansas. Latest CAM consensus
supports thunderstorm potential moving into central/north-central KS
by 5-8pm, and propagating eastward thereafter.

Combination of instability and deep layer shear is not overly
impressive, although likely sufficient given strong/deep forcing,
for a handful of strong-severe storms before roughly midnight.
Inverted-V sounding profiles and associated high levels of downdraft
CAPE should support strong/damaging wind gusts as the primary threat
with the strongest activity. However, modest deep layer shear of 30-
35 kts could promote some supercell structures early on in the
event, supporting a threat for some lower-end large hail across
central/north-central KS. Given the likelihood of strong
downdrafts/cold pools, activity should tend to consolidate into 1-2
forward propagating systems, supporting primarily a wind threat as
activity moves east.

Sunday is looking a bit more interesting thunderstorm-wise, mainly
across southeast Kansas. Cooler temperatures aloft associated with
the passing shortwave overhead along with continued rich boundary
layer moisture will support higher levels of instability compared to
today. Additionally, deep layer shear is progged to be slightly
higher than today given west/northwest flow aloft. The main concern
for storm initiation though is the apparent lack of a surface
trigger. This problem would be overcome if tonight's convection lays
out a formidable outflow boundary across the region. All-in-all, if
storms are able to develop, instability/shear combo would support
strong to severe storms. Stay tuned.

Otherwise, hot above normal temperatures will continue the next
several days, as progged by deterministic consensus of low-level
thickness. Thinking forecast highs in the 90s to low 100s are
realistic. The greatest combination of high temperatures/dewpoints
will be Monday and Tuesday, when forecast afternoon heat indices are
around 105 degrees for many. Will continue to monitor for possible
heat advisory headlines. Fortunately, breezy south winds both days
should help temper the "feels like" temperature some.

.LONG TERM...(Tuesday night through Saturday)
Issued at 255 PM CDT Sat Aug 7 2021

Deterministic and ensemble consensus attempts to ooze a cold front
south into central/northern KS Tuesday night and Wednesday, which
could be a focus for thunderstorm development. Still quite a bit of
uncertainty though surrounding this period, so only went with low to
modest PoPs for now. This front should tend to dissipate/wash out,
so there shouldn't be much relief in the heat. However,
deterministic and ensemble consensus supports a somewhat more
appreciable cold front by Thursday night-Friday. This could support
additional storm chances, along with cooler daytime temperatures in
the 80s-90s, along with decreasing dewpoints and associated
humidity.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 629 PM CDT Sat Aug 7 2021

Main concerned for this TAF period will be the approaching
thunderstorm activity for the KRSL, KGBD and KSLN terminals. KRSL
and KGBD will have the greatest risk of higher winds and hail
potential. Most of this activity will push through KRSL and KGBD
by 02Z with KSLN the next one up. By 03Z, KSLN will likely see the
thunderstorm activity. Not as confident with the severity of the
activity for KSLN but stronger winds and hail are still possible
there until 06Z.

KHUT and KICT look to be on the southern extent of the
thunderstorm activity. KHUT is much more likely to get the thunder
while KICT is more likely to just miss it. That said, can't rule
out the potential for thunder coming on station at KICT around 06Z
tonight. KCNU will get the thunderstorm activity and is not likely
to see thunder until closer to 10Z but not confident on the extent
of the thunderstorm potential.

By 12Z, all areas are expected to return to VFR conditions as the
main push of thunderstorm activity pushes off to the east.

Metzger

&&

.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT    74  97  74  99 /  20  20  10   0
Hutchinson      70  97  73 100 /  30  10  10   0
Newton          72  95  73  98 /  30  20  10   0
ElDorado        73  94  74  97 /  20  20  20  10
Winfield-KWLD   75  95  75  97 /  30  30  20  10
Russell         66  97  71 103 /  60   0   0   0
Great Bend      66  94  69  99 /  60   0   0   0
Salina          70  97  73 102 /  60  10   0   0
McPherson       70  95  72  99 /  50  10  10   0
Coffeyville     76  93  75  95 /  30  30  30  10
Chanute         76  92  75  94 /  30  30  30  10
Iola            76  91  75  93 /  30  30  30  10
Parsons-KPPF    75  92  75  95 /  30  30  30  10

&&

.ICT WATCHES/WARNINGS/ADVISORIES...
None.
&&

SHORT TERM...ADK
LONG TERM...ADK
AVIATION...ELM

Hazardous Weather Outlook
National Weather Service Wichita KS
337 PM CDT Sat Aug 7 2021

KSZ032-033-047>053-067>072-082-083-091>096-098>100-082045-
Russell-Lincoln-Barton-Ellsworth-Saline-Rice-McPherson-Marion-Chase-
Reno-Harvey-Butler-Greenwood-Woodson-Allen-Kingman-Sedgwick-Harper-
Sumner-Cowley-Elk-Wilson-Neosho-Chautauqua-Montgomery-Labette-
337 PM CDT Sat Aug 7 2021

This hazardous weather outlook is for portions of Central Kansas,
South Central Kansas and Southeast Kansas.

.DAY ONE...Tonight

Scattered thunderstorms are expected this evening through tonight,
mainly along and north of the Highway 56 corridor across central,
north-central, east-central, and northeast Kansas. A handful of
strong to severe storms are possible before about midnight. The
primary threat will be strong to damaging wind gusts of 50 to 70
mph, although a few instances of large hail are possible as well
before about 9 PM across central and north-central Kansas.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

There is some potential for thunderstorm development Sunday
afternoon and evening, mainly across southeast Kansas. If storms are
able to form, severe weather is possible. Stay tuned for later
forecasts.

Dangerous heat will continue across the region through Tuesday, with
afternoon through early evening heat indices ranging from 100 to
105 degrees.

There is a chance of thunderstorms Tuesday afternoon through
Wednesday, mainly across the northern half of Kansas. At this time,
a few strong to marginally severe storms appear possible.

.SPOTTER INFORMATION STATEMENT...

Reports of damaging winds, large hail, heavy rainfall, and flooding
are always greatly appreciated.

&&

For a graphical version of this information, see our webpage at:
https://weather.gov/crh/ghwo?sid=ict