WPC Met Watch |
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Mesoscale Precipitation Discussion: #0213 (2022) |
(Issued at 936 PM EDT Tue May 17 2022
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MPD Selection |
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Mesoscale Precipitation Discussion 0213
NWS Weather Prediction Center College Park MD
936 PM EDT Tue May 17 2022
Areas affected...Central/Eastern KS...Western MO
Concerning...Heavy rainfall...Flash flooding likely
Valid 180135Z - 180735Z
SUMMARY...Showers and thunderstorms are expected to grow upscale
in coverage heading into the overnight hours for areas of central
to northeast KS and eventually into areas of western MO. Locally
slow-moving, training, and merging convective cells with very
heavy rainfall rates will likely support some areas of flash
flooding.
DISCUSSION...A low-amplitude shortwave trough ejecting east out
across the central Plains will be interacting with a frontal zone
and a pool of moderate to strong instability for expanding
clusters of heavy showers and thunderstorms heading into the
overnight hours. The latest RAP analysis shows as much as 2000 to
3000+ j/kg of MLCAPE across areas of central/eastern KS and far
western MO, and the airmass is rather moist too with PWs of 1.3 to
1.5 inches. This is locally as much as 1 to 2 standard deviations
above normal.
The main driver of the excessive rainfall threat across areas of
central/eastern KS and gradually western MO will be seeing areas
of slow-moving convective cells and cell-mergers as the 18Z HREF
guidance and especially the last couple runs of the experimental
WoFS support. In fact, the last couple of runs of the WoFS has
been trending notably wetter across areas of northeast KS with
50th percentile of 6-hourly accumulated rainfall now reaching
upwards of 5 to 6 inches across portions of Lyon, Wabaunsee, and
Morris counties going through 06Z.
Rainfall rates with the increasingly organized areas of convection
should approach or locally exceed 2 inches/hour given the
available instability, and gradual increase in a southerly
low-level jet (30 to 40+ kts) which will favor greater moisture
transport. Given the set-up with slow cell-motions,
repeating/training rounds of convection, and the aforementioned
cell-merger concerns, some localized 6+ inch rainfall amounts will
be possible.
The extreme rainfall rates and heavy totals should promote
concerns for flash flooding, with generally a focus on northeast
KS for the heaviest rainfall totals and runoff threat going
through midnight. The urban corridors and adjacent suburbs
involving the greater Topeka and Kansas City metropolitan areas
will need to be closely monitored for locally enhanced runoff
concerns. Adjacent areas of western MO going toward and past
midnight will also be a likely focus for heavy rainfall potential
and flash flooding concerns going deeper into the overnight period.
Orrison
ATTN...WFO...DDC...EAX...GID...GLD...ICT...LSX...SGF...TOP...
ATTN...RFC...ABRFC...MBRFC...NWC...
LAT...LON 39549860 39439657 39499466 39449326 38629281
38099368 37919574 38029711 38409897 38979970
39399965
Last Updated: 936 PM EDT Tue May 17 2022
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