Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Sat Jun 03 2023 19:17:14

AWUS01 KWNH 031917
FFGMPD
MOZ000-ARZ000-OKZ000-KSZ000-NEZ000-COZ000-040100-

Mesoscale Precipitation Discussion 0417
NWS Weather Prediction Center College Park MD
316 PM EDT Sat Jun 03 2023

Areas affected...Central Plains

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

Valid 031915Z - 040100Z

SUMMARY...Lines of thunderstorms in an increasingly favorable
environment to support training aloft may result in flash flooding
this afternoon.

DISCUSSION...Doppler Radar depicted an elongated cluster of
thunderstorms from northern Kansas on southeast into northeast
Oklahoma and western Arkansas. A surface trough was located along
the same area as the cluster of storms, acting as a trigger for
these storms. RAP mesoanalysis showed as much as 1,000 MLCAPE as
of 18Z, but is forecast to reach 2,000 J/kg as far south and west
as southeast Kansas and northeast Oklahoma in a couple hours.
MLCAPE changes over the past 3-hours have risen 600-1,000 J/kg
from northern Kansas to western Arkansas already. In addition, PWs
are also on the rise with >1.5" PWs northeast Oklahoma and eastern
Kansas. Farther west PWs may not be as high in content, but values
as high as 1.2" are at, to even slightly above, the 90th
climatological percentile.

One of the primary concerns is the increasingly saturated profiles
throughout the at-risk area. RAP guidance shows low-mid level RH
values ranging between 80-90% in some cases. In addition, the
southeasterly flow at 850mb will linger into the evening hours,
allowing for the ongoing 850mb theta-e advection to run parallel
to the surface trough. The other factor to consider is
back-building convection. Area averaged HRRR soundings, sampled in
northern Kansas and in northeast Oklahoma, all showed upshear
Corfidi vectors <10 knots. When factoring in warm cloud layers as
deep as 8,000' and a moistening atmosphere, thunderstorms will be
capable of producing hourly rainfall rates up to 2"/hr. These kind
of rates with the potential for training could result in flash
flooding.

Looking at flash flood guidance (FFG), the lowest 1-hr FFGs are in
northwest Kansas where they are <1.5". Farther east, values
generally bottom out at 1.5", but are on average closer to 2".
This should help to limit the areal coverage for instances of
flash flooding, but given the training potential, areas that are
beneath training lines of thunderstorms could see excessive runoff
and street flooding. Locations with highly sensitive soils are
also more susceptible to flash flooding. Western and northern
Kansas are most sensitive given the 300-400% of normal rainfall
over these regions the last 7-days.

Mullinax

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!7VdY9mrTWCudrJqf-CJbf9jzjo5ofsC7edChjMakgQyD6ZsewgJ4Foco4hUQ3-ZJCySz=
SwuOjP0vA27YFU-iulsGu0s$  for graphic product...

ATTN...WFO...BOU...DDC...EAX...GID...GLD...ICT...LBF...OAX...
SGF...TOP...TSA...

ATTN...RFC...ABRFC...LMRFC...MBRFC...NWC...

LAT...LON   41010203 41019922 40339732 39149571 38389515=20
            36269399 35829512 37119681 38539929 39900255=20
=20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to
https://lists.illinois.edu and use the "Unsubscribe" link.  Otherwise email
Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.14-Linux
 * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

.