994
AWUS01 KWNH 271631
FFGMPD
OKZ000-KSZ000-272100-

Mesoscale Precipitation Discussion 0182
NWS Weather Prediction Center College Park MD
1231 PM EDT Sat Apr 27 2024

Areas affected...Northwest Oklahoma...South-central Kansas...

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

Valid 271630Z - 272100Z

SUMMARY...A few observations suggest higher rainfall efficiency,
rates over 2-2.5"/hr and increasingly favorable orientation for
possible repeating pose at least an isolated or widely scattered
risk of flash flooding through early afternoon.

DISCUSSION...GOES-E Visible/10.3um EIR loops depict strong
destabilization ongoing across northwest OK from Roger Mills to E
Major, entering Grant county... with further weaker cells nearing
the KS border in Kay county.  Please refer to SPC MCD 538-539 for
additional details about unfolding severe weather hazards.  Recent
16z surface analysis denotes a strong dryline extending southward
from surface wave near DDC with a slightly bowed segment in
proximity to I-40/Wheeler county TX.  RAP analysis and VWP depict
some solid confluence along this bow enhancing moisture flux
convergence while expanding orientation toward the east.  Cells
further eastward toward Major county appear to have developed at
the nose of an enhanced moisture feature through 925-850mb that
orients northeastward into south-central KS.  The convergence
along the axis has provided additional orthogonal convergence flux
into the developing storms and have increased rainfall efficiency
in the lowest profile with a few observations noting 1.5"/45 min
near NW Blaine county and 1.75" in SW Roger Mills county, not
within the greatest reflectivity/KDP alignment of heavy rainfall
that was further east in the county where there is a lack of
observations.

The area has been in a significant drought and FFG values are near
the extremes of 3"/hr and 4-5"/3hrs...but in driest conditions,
extreme rates and hard grounds are difficult for much infiltration
and increased run-off so spots of flash flooding could be possible
with totals over 2-3" in 1-2hrs.

Of concern, further duration of heavy rainfall with
training/repeating profiles may also be starting to evolve as the
upper-level jet streak is starting to come over-top the region as
steering flow appears to be oriented just north of parallel to the
convective line`s orientation.  Combined this with 500-1000
thickness divergence across NW OK into south-central KS should aid
in slowing forward propagation/Corfidi vectors, allowing for
increased duration. Lastly, cells are strongly rotating and have
shown some signs of southward deflection and slowing as Bunker`s
vectors appear to be reducing and orienting favorably to the
convective line as well.  So while there are increasing signals
toward favorable spots of 2-4" of rain over the next few hours;
many factors have to align to overcome the dry ground conditions
and therefore flash flooding is only considered possible and to be
isolated or widely scattered in nature for portions of Northwest
OK into south-central KS into early afternoon.

Gallina

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

ATTN...WFO...DDC...ICT...OUN...

ATTN...RFC...ABRFC...NWC...

LAT...LON   38159741 38099664 37629639 36749702 35249931
            35119992 35619998 36529948 37639841