Special Weather Statement, NWS Kansas City, MO

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
550 PM CDT Sun Jun 20 2021

.Discussion...
Issued at 252 PM CDT SUN JUN 20 2021

After morning thunderstorms have moved out of the area clear skies
and high sun has allowed for rapid recovery of the airmass in the
wake of those storms. Temperatures across the area have warmed back
into the lower to middle 90s, and along with dewpoints pushing 70
degrees and steep low to mid level lapse rates ML CAPE has built
3000 J/kg. Mesoanalysis indicates at least a little bit of CINH left
across the area, which has for the most part kept storm formation at
bay, but cumulus clouds will continue to build as the convective
temperature is reached. With the mid level trough responsible for
the AM thunderstorms just moving through the area there should be
some subsidence in the mid levels, which will also keep storms at
bay for another couple hours. Short term modeling indicates the
CAP/CINH will erode in the next couple of hours, which will then
allow for freely developing storms this afternoon once a trigger
presents itself. A cold front, which is analyzed across NE KS into
SW Iowa will be the main focus for afternoon and evening convection.
Initial storms will form along that boundary, likely in far southern
Iowa, and coverage will stretch southward along the boundary into NW
Missouri. One area to watch for more organized development will be
far northern Missouri, into southern Iowa where an inverted trough
will keep winds a little more backed ahead of the creeping cold
front. Mid level flow out of the northwest may actually keep storm
development a little more discreet, at least at first, as coverage
may be scattered early on. The high CAPE along with strong deep
layer shear will yield organized structures, perhaps mature
supercells in the 4 pm to 7 pm range, again across far northern
Missouri and southern Iowa. While the overall tornado threat is low
for this event, lending to the warm surface conditions and a lack of
any formidable LLJ while storms are most likely to be surface based,
the backed winds and possible discreet mode across northern Missouri
will yield an outside chance at a tornado or two. Further south
along the boundary, scattered convection will continue to fire as
the boundary moves into the uncapped environment. Expect the
southern development to occur an hour or two after the initial Iowa
development, which will put the KC Metro in the window for storm in
the 5 pm to 7 pm range. Despite the uniform low level forcing along
the boundary, hi-res models continue to imply scattered development,
which may yield breaks in the storm coverage. Where storms do form
expect gusty or perhaps damaging winds and hail as high as quarters
to golf balls. As cold pools form convective coverage should
increase and line segments should accelerate east and south ahead of
the boundary. As the sun sets CINH will increase and the wind threat
will eventually decrease with time tonight. Expect the bulk of the
storms to be south and east of the area by the overnight hours, with
lingering trailing stratiform showers through the overnight. Expect
some lingering showers in the post frontal environment going into
Monday, but those showers should remain closer to the sagging
synoptic front, so a strong northern push of any Monday rain will be
limited, likely to areas along and south of the I-70 corridor.

Temperatures on Monday and Tuesday will be rather pleasant and
welcomed relief from the persistent heat and humidity. The surface
trough will take over the area, which will keep a steady supply of
relatively dry and cool air, more reminiscent of early autumn as
opposed to early summer. The relief will be somewhat short-lived as
the surface ridge moves east and southerly return flow brings warm
and moist air back into the region for the middle to latter part of
the upcoming week. The combination of a resupply of moisture and an
increasingly active mid level pattern will introduce several chances
for rain in the Thursday through Saturday time frame.

&&

.Aviation...(For the 00Z TAFS through 00Z Monday Evening)
Issued at 537 PM CDT SUN JUN 20 2021

Primary aviation concern will be TSRA chances at the beginning.
Timing remains the same as the 18Z issuance, between 00 and 03Z.
VFR conditions will then persist, with shower chances in the
morning, around 12Z through 16Z. Winds will start out of the west,
becoming more northwest through the end of the period.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&

Discussion...Leighton
Aviation...Kurtz

Hazardous Weather Outlook
National Weather Service Kansas City/Pleasant Hill MO
1236 PM CDT Sun Jun 20 2021

KSZ025-057-060-102>105-MOZ001>008-011>017-020>025-028>033-037>040-
043>046-053-054-211745-
Atchison KS-Miami-Linn KS-Doniphan-Leavenworth-Wyandotte-Johnson KS-
Atchison MO-Nodaway-Worth-Gentry-Harrison-Mercer-Putnam-Schuyler-
Holt-Andrew-De Kalb-Daviess-Grundy-Sullivan-Adair-Buchanan-Clinton-
Caldwell-Livingston-Linn MO-Macon-Platte-Clay-Ray-Carroll-Chariton-
Randolph-Jackson-Lafayette-Saline-Howard-Cass-Johnson MO-Pettis-
Cooper-Bates-Henry-
1236 PM CDT Sun Jun 20 2021

This hazardous weather outlook is for northwest...north central and
west central Missouri...as well as extreme eastern Kansas.

.DAY ONE...This Afternoon and Tonight

 Temperatures in the 90s and heat index values in the upper 90s to
 near 100 can be expected this afternoon.

 Strong to severe thunderstorms are possible this evening into the
 overnight hours. Large hail and damaging winds are the main
 hazards.

 More detailed information can be accessed at...
 https://www.weather.gov/eax/hwo

.DAYS TWO THROUGH SEVEN...Monday through Saturday

 Hazardous weather is not expected at this time.

 More detailed information can be accessed at...
 https://www.weather.gov/eax/hwo

Special Weather Statement
National Weather Service Kansas City/Pleasant Hill MO
607 PM CDT Sun Jun 20 2021

MOZ012-202345-
Andrew MO-
607 PM CDT Sun Jun 20 2021

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN ANDREW COUNTY UNTIL 645
PM CDT...

At 607 PM CDT, Doppler radar was tracking a strong thunderstorm over
Amazonia, or near Savannah, moving east at 30 mph.

Nickel size hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Savannah, Country Club Villa, Country Club, Union Star, Amazonia,
Cosby and Helena.

This includes the following highways...
 Interstate 29 between mile markers 52 and 64.
 Interstate 229 between mile markers 10 and 14.

A Severe Thunderstorm Watch remains in effect until 1100 PM CDT for
northeastern Kansas...and northwestern Missouri.

LAT...LON 3982 9460 3982 9487 3983 9489 3984 9492
      3986 9494 3988 9493 3990 9495 3996 9496
      3999 9460
TIME...MOT...LOC 2307Z 272DEG 24KT 3990 9488

Blair