Flash Flood Warning 16, NWS Kansas City, MO

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
317 AM CDT Wed Aug 2 2023

.Discussion...
Issued at 316 AM CDT WED AUG 2 2023

Key Message:

- Thunderstorms with intense rainfall are ongoing from north central
through central Missouri.

- Dangerous heat expected to build north today with heat indices of
ranging from 105 to 110 across the southwestern quarter of the
forecast area, including the KC metro.

- Additional strong to severe thunderstorms possible this afternoon
and evening.

As of 07Z, thunderstorms are ongoing across north central to
northeastern and central Missouri. This is occurring on the nose of
southwesterly low-level jet intersecting an elevated boundary
within an environment characterized by 2000 J/kg of MUCAPE,
effective bulk shear of 30-45 kts, and precipitable water values
nearing 2.2". Upper-level winds are nearly parallel to the elevated
boundary and as a result, just like last night, storms initiate
northwest, track to the southeast, and train over the same areas.
With the extremely high precipitable water values, the storms
have been extremely efficient rainfall producers. MRMS
precipitation estimates are already nearing 4" through Sullivan
county as of 07Z. We will likely see a swath of 4-8" through the
northeastern sections of the forecast area and likely see some
localized 10" amounts. Flash flooding is very likely, if not
ongoing, in this area this morning. From famine to feast for
rainfall for areas that have been hardest hit by the ongoing
drought conditions.

To the south and west of this rainfall, very hot and humid
conditions are expected. Yesterday afternoon may have foretold the
heat the area is likely to see today. The pattern is essentially
shifted to the northeast by up about one to two counties. This
suggest Linn county, Kansas will see temperatures around 102 with
near 100 degree readings in the southern KC metro. With dewpoints
in the middle 70s heat index values will range from around 100 to
105 across the north side of the KC metro to 110 on the southern
side of the advisory. The northern tier of counties within the
current heat advisory are the most uncertain. With our latest
temperatures forecast to be several degrees cooler due to cloud
cover and possible showers/storms, heat index values top out
around 100. Given the uncertainty with temperatures and if cloud
cover can erode, like it did today in the KC area, my plan is to
keep the advisory going, even though there is a chance it won't
hit criteria. If skies clear out, they'll likely soar into the
100-105 range the KC area did yesterday.

The other concern for today is the potential for new convection to
develop during the afternoon and evening hours. This looks like it
would develop on a boundary ahead of an MCV moving into the area
from convection over the Plains. If this occurs, there will be
potentially extreme CAPE with SBCAPE values between 4000 and 5000
J/kg at peak heating. This will occur within a strongly sheared
environment with 40 to 50 kts of 0-6km shear. This environment will
support supercells initially before a transition to a more linear
mode. Given the potential for supercells, all severe hazards will be
in play, including tornadoes, before transitioning to primarily a
wind threat.

Beyond today, the upper ridge broadens out and gets shunted
southward through the end of the week. This keeps the bulk of the
heat south of the area into southern Kansas and Missouri. This shift
in the pattern will also keep precipitation chances going with
westerly upper-level flow. A stronger shortwave trough will move
through the area next week and that will usher in a cooler and
drier airmass next week. Forecast highs look to be about 5 to
possibly 10 degrees below normal next week with dewpoints in the
low to mid 60s vs the mid to even upper 70s we've seen the last
few days.

&&

.Aviation...(For the 06Z TAFS through 06Z Wednesday Night)
Issued at 1244 AM CDT WED AUG 2 2023

Currently, there are thunderstorms north central to northeastern
Missouri, moving in a southeasterly direction. Additionally,
there are thunderstorms in central and western Kansas moving east-
southeasterly towards the region. At this time, confidence is low
in them impacting the area so I did not mention them in the
forecast at this point.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...Heat Advisory from 11 AM this morning to 8 PM CDT this evening
     for KSZ025-057-060-103>105.

MO...Heat Advisory from 11 AM this morning to 8 PM CDT this evening
     for MOZ020-021-028>030-037>039-043>046-053-054.

     Flood Watch until 10 AM CDT this morning for MOZ006>008-015>017-
     024-025-032-033-040-046.

&&

Discussion...CDB
Aviation...Collier

Hazardous Weather Outlook
National Weather Service Kansas City/Pleasant Hill MO
500 AM CDT Tue Aug 1 2023

KSZ025-057-060-102>105-MOZ001>008-011>017-020>025-028>033-037>040-
043>046-053-054-021000-
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-
500 AM CDT Tue Aug 1 2023

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

.DAY ONE...Today and Tonight

 There is a chance for a few rounds of thunderstorms this morning and
 again tonight in Central and Eastern Missouri. Heavy rains, capable
 of producing flooding is possible. Severe weather is not expected
 however, a few strong storms capable of small hail and gusty winds
 may be possible.

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

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

 Several additional rounds of thunderstorms possible each day this
 week. The threat of severe weather is low.

 Dangerous heat may be possible on Wednesday south of the Missouri
 River.

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

Preliminary Local Storm Report
National Weather Service Kansas City/Pleasant HIll MO
104 AM CDT Wed Aug 2 2023

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0102 AM     Hail             Princeton               40.40N 93.58W
08/02/2023  E0.70 inch       Mercer             MO   Public

&&

CDB