Flash Flood Guidance

AWUS01 KWNH 222152

Mesoscale Precipitation Discussion 0481
NWS Weather Prediction Center College Park MD
551 PM EDT Sat Jun 22 2019

Areas affected...Central/Eastern KS...Northwest MO...Southwest
IA...Southeast NE

Concerning...Heavy rainfall...Flash flooding possible

Valid 222151Z - 230351Z

Summary...Developing thunderstorms this afternoon across
central/eastern Kansas will pose a flash flood threat into the
evening hours. With multiple clusters of storms likely, 2-4" with
locally higher amounts will be possible through 03z.

Discussion...GOES-East IR imagery showed rapidly cooling cloud
tops associated with convection developing across central Kansas
late this afternoon. This activity is working along an area of low
pressure over south-central KS with a stationary boundary draped
north/south through KS and NE. The warm sector is extremely
unstable and moist, characterized by dewpoints in the middle to
even upper 70s. This is yielding MLCAPE values of 5000 to 6000
J/kg across much of the outlook area. Additionally, PWs are
seasonably high with the latest TPW blended product showing values
of 1.5 to 1.7 inches.

Over the next several hours, convection will continue to fire up
along the boundary and move east/northeast across central/eastern
KS and into portions of northwest MO, far southwest IA, and
southeast NE. Rain rates will be high and intense at times given
the available moisture and instability. The 12z HREF supports this
idea, with 30-60 percent probabilities of 1-hr totals exceeding 2
inches late this afternoon into the evening hours across eastern
KS and northwest MO.

The general consensus from the latest hi-res models supports
totals of 2-4" in the strongest clusters with some locally higher
amounts of 5" possible. The most focused area for the higher end
amounts seem to be across northeast KS and northwest MO,
potentially in and around the KC metro area. As the evening wears
on, the low-level jet will begin to increase to 30-35 kts,
providing a steady flux of moisture into the area. There is some
potential for training convection as the mean flow in the RAP
forecasts show a southwest to northeast orientation, which is
nearly parallel to the expected storm motions.

Additionally, antecedent conditions are more saturated, with the
recent 7-day precipitation departures mostly in the 200-300
percent range, but several areas also as high as 600 percent of
normal. As expected, the National Water Model indicates very high
to much above normal streamflows in the area. The latest FFG are
relatively low with 1-hr values of 1-1.5", which seems attainable
given the convection developing already.


...Please see www.wpc.ncep.noaa.gov for graphic product...



LAT...LON   41169509 41139415 40849294 40089287 39419309
            38619429 38079504 37239660 37069711 37249791
            38459873 39799859 40669657 40979571