926
AWUS01 KWNH 110756
FFGMPD
OKZ000-111355-

Mesoscale Precipitation Discussion 0859
NWS Weather Prediction Center College Park MD
356 AM EDT Sun Aug 11 2024

Areas affected...Oklahoma

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

Valid 110755Z - 111355Z

SUMMARY...Showers and thunderstorms will be increasing in coverage
going through the early to mid-morning hours. Some isolated to
widely scattered instances of flash flooding will be possible
where any backbuilding and training of cells occur.

DISCUSSION...The latest GOES-E IR satellite imagery in conjunction
with dual-pol radar shows showers and thunderstorms developing and
expanding in coverage across areas of central and western OK. The
convection which is elevated north of a quasi-stationary front
near the Red River is being facilitated by the strengthening and
gradual veering of a southerly low-level jet out ahead of
low-amplitude shortwave energy ejecting across the central Rockies
and out into the High Plains.

MUCAPE values across the region are locally as high as 1000 to
1500 J/kg with the strongest nose of the low-level jet focused
across the TX Panhandle where VWP data shows southerly 850 mb flow
of 40+ kts. This energy though will continue to shift east across
western and central OK over the next several hours going through
12Z (7AM CDT) and should promote an additional uptick in the
coverage and local organization of heavier showers and
thunderstorms.

PWs across the region are forecast to increase early this morning
to locally near 2 inches over central OK with the aid of the
strengthening moisture transport into the region, and this coupled
with the instability and relatively strong shear overhead should
favor some rainfall rates of 1.5 to 2 inches/hour with the
stronger and more organized cells.

As the warm air advection regime strengthens and the low-level jet
veers and becomes a bit better aligned with the deeper layer
steering flow this morning, there will be some growing concerns
for backbuilding and training convective cells. The 00Z HREF
guidance suggests the greatest potential for this will be over
central OK and especially toward the 12Z (7AM CDT) time frame and
beyond.

Some localized rainfall amounts by mid-morning may reach 3 to 5
inches which is consistent with the consensus of the HREF
solutions. The antecedent conditions are very dry across western
and central OK, and so these rains will initially be going into
moistening the soil conditions, but with locally persistent heavy
rainfall rates over time, eventually there may be some isolated to
widely scattered instances of flash flooding. The urban corridors
will be most susceptible to these potential impacts which will
include the Oklahoma City metropolitan area.

Orrison

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

ATTN...WFO...OUN...TSA...

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

LAT...LON   36809742 36609606 36199511 35589472 34939524
            34579645 34749848 35279960 35999990 36459965
            36729889