Mesoscale Precipitation Discussion 0746
NWS Weather Prediction Center College Park MD
501 PM EDT Sun Sep 02 2018

Areas affected...central KS/southeast NE/northwest MO/southern IA

Concerning...Heavy rainfall...Flash flooding likely

Valid 022055Z - 030255Z

Summary...An Increasing coverage of thunderstorms is expected
through 00Z and 03Z across central KS into southeastern NE,
southern IA and northern MO. 3-5 inches of rain is expected
through 03Z, some of which will overlap with recent heavy rainfall
across the region posing an increased threat for flash flooding.

Discussion...2030Z Visible satellite imagery and surface
observations placed a surface trough, enhanced by differential
heating, from west-central KS into northwest MO. Radar imagery
already showed scattered thunderstorms across central KS,
increasing in coverage out ahead of a strung out low-mid level
trough axis with a couple of vorticity centers stretching across
the central High Plains. The 20Z SPC mesoanalysis showed 1500-2500
J/kg MLCAPE across KS into MO and southern IA with eroding CIN
confirmed by the recent increase in thunderstorm development
across KS. East of 100W, GPS sites and the 18Z LMN sounding showed
precipitable water values of 1.5 to 1.8 inches across KS/NE/IA/MO.

Increased forcing for ascent over the central Plains and Midwest
is expected through 00Z as subtle eastward movement of the
mid-level trough axis occurs. The RAP has been trending stronger
with a forecast 70-90 kt upper level jet forecast to lie from
northwest IA to Lake Superior, placing the right entrance region
and added upper level divergence over central KS/NE between
00-03Z. Meanwhile, closer to the surface, 850 mb wind speeds
should increase from the south into the 20-30 kt range across KS
beyond 00Z with overrunning of the aforementioned surface trough
and any newly developed convective outflow boundaries with nearly
unidirectional flow above the LFC supporting training/repeating of
cells from southwest to northeast. 3-5 inches of rain through 03Z
is expected in a few locations, some of which is expected to
overlap with recent heavy rainfall and lowered Flash Flood
Guidance, supporting flash flooding in a few locations.

Otto

ATTN...WFO...DDC...DMX...EAX...GID...GLD...ICT...OAX...TOP...

ATTN...RFC...ABRFC...MBRFC...NCRFC...

LAT...LON   41039385 40879285 40499273 40079312 39439439
            38959593 38339867 38220018 39090012 40139809
            40649648 40969495