190
AWUS01 KWNH 300802
FFGMPD
TXZ000-OKZ000-KSZ000-COZ000-NMZ000-301400-

Mesoscale Precipitation Discussion 0519
NWS Weather Prediction Center College Park MD
400 AM EDT Sun Jun 30 2024

Areas affected...much of southern KS into portions of northern OK,
southeast CO, and northeast NM

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

Valid 300800Z - 301400Z

Summary...Rainfall rates of 1-3"/hr likely to result in localized
totals of 3-5". Isolated to scattered instances of flash flooding
are likely.

Discussion...Convection has proliferated over the past couple of
hours across much of southern KS and surrounding portions of
OK/CO, just upstream of more active, deep convective activity over
northeast NM. This initiation and proliferation is in response to
warm air advection (WAA) and moisture transport situated in the
low levels (most focused around 850 mb), which has resulted in a
rapid increase in elevated instability (+200-600 J/kg of MUCAPE in
the past 3 hours, resulting in total values of 1000-2000 J/kg).
Deep layer moisture is increasing in tandem, as depicted by a
gradient of precipitable water values of 1.6-2.3 inches (near or
above record levels, per DDC sounding climatology). Even effective
bulk shear is quite impressive, ranging from 30-50 kts. This
environment is quite supportive of heavy rainfall, and deep layer
(850-300 mb) mean winds of only 5-10 kts suggests that storm
motions will remain quite slow until sufficient organization
occurs for propagation (or until storms exhaust available
instability, which looks less likely given fresh moisture
transport and sufficient shear). In addition, a
shortwave/mesoscale convective vortex (MCV) in association with
the aforementioned deep convection over northeast NM may provide
an additional source of broad lift/shear for upscale growth (and
this feature is quite apparent via GOES-East water vapor imagery).

While the HRRR and FV3 struggle to initiate/maintain convection,
most of the other hi-res CAMs from the 00z cycle (i.e. ARW,
ARW2/NSSL, and NAM-nest) have a more realistic depiction of QPF
through 14z (though still too slowly based on observational
trends). For this reason have favored the HREF probability matched
mean depiction, which suggests localized totals of 3-5" over
southeast KS (and somewhat lower 1-3" totals for surroundings).
Expressed in terms of exceedance probabilities (using a 40-km
neighborhood method), the HREF suggests 20-40% odds of exceeding
3" through 15z. Associated Flash Flood Guidance (FFG) generally
ranges from 2.0-4.0" (over a 3-6 hour period), but shorter-term
hourly totals of up to 2-3" (due to both the slow storm motions
and potential for training) will more easily exceed associated
(1-hr) FFG of 1.5-2.0". As a result, isolated to scattered
instances of flash flooding are considered likely.

Churchill

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

ATTN...WFO...ABQ...AMA...DDC...GLD...ICT...OUN...PUB...TSA...

ATTN...RFC...ABRFC...MBRFC...WGRFC...NWC...

LAT...LON   38810202 38739987 38329810 37419633 36459675
            36219782 36559889 36650038 36580231 36330307
            35420405 35540558 36540571 37460495 38320357