Mesoscale Precipitation Discussion 0309
NWS Weather Prediction Center College Park MD
428 PM EDT Wed Jun 03 2026

Areas affected...South-central NEB...North-central KS...

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

Valid 032030Z - 040200Z

SUMMARY...Efficient convective clusters becoming oriented to mean
flow to support some repeating/training with slow east/southeast
propagation.  Rates of 1.75-2"/hr and spots of 2-3.5" may result
in localized possible flash flooding.

DISCUSSION...Regional RADAR and GOES-E Visible imagery depict an
expanding cluster of thunderstorms across south-central NEB,
generally orthogonal to the deep layer moisture axis and southerly
low-level jet.   Total PWats of 1.5-1.7" mainly loaded below 700mb
per CIRA LPW advected on 15-20kts southerly flow is providing
solid moisture flux convergence.   Additionally, initial
convection was placed favorably within broad cyclonic entrance
region to upper-level jet speed max (enhanced by early morning
convective complex in NM/OK/TX) continues to allow for upscale
enhancement with favorable divergence aloft.  As such, individual
cells have cycled toward an increasingly west to east line (with
smaller faster moving cells on the north side of the initial cold
pool racing away).  This has favorably oriented the expanding line
due to orthogonal moisture flux convergence.   Full insolation
through the morning/afternoon provided ample unstable environment
with MLCAPEs to 2500 J/kg. As such, moisture loading is supporting
rates of 1.75-2"/hr rates.

Deep layer flow is generally weak with 15-20kts mean flow to the
northeast while propagation is similarly about 5kts
east/southeast.  Visible imagery denotes further congestion of the
cu field along the southern edge that suggests a further southern
propagation is probable.  Additional upstream development across N
central KS may further allow for mergers/intersection later this
evening near/along the border.  Given slow motions, localized
2-3.5" totals are possible.  The evolution and placement matches
the RRFS and Canadian GEM solutions (4"+) which are typically too
hot/intense overall, but the other solutions from the HRRR/ARWs
remained too capped compared to reality. 

Hydrologically, the rates of up to 2"/hr and spots to 3.5"/3hrs
are in the vicinity of the FFG values in the region, but suggest
localized exceedance is sufficient for localized possible
incidents of flash flooding to occur through this evening as the
complex continues to evolve and slowly drift east and south with
time.

Gallina

ATTN...WFO...GID...GLD...OAX...TOP...

ATTN...RFC...KRF...NWC...

LAT...LON   41509767 41289702 40729672 40029682 39529713
            39299767 39259857 39289957 39700009 40230014
            40519986 40949940 41229860