AWUS01 KWNH 121109
FFGMPD
ARZ000-TXZ000-OKZ000-121700-

Mesoscale Precipitation Discussion 0391
NWS Weather Prediction Center College Park MD
708 AM EDT Fri Jun 12 2026

Areas affected...Southern & Southeast Oklahoma...Northern
Texas....Far Southwest Arkansas...

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

Valid 121115Z - 121700Z

SUMMARY...Decaying MCS

DISCUSSION...GOES-E 10.3um and Regional RADAR depict mature MCS
across Southeastern OK extending into southwest AR with increasing
bowing/cold pool structure evident along the southern edge of the
complex.  WV suite shows the cluster is at the far trailing edge
of the northern stream longwave trough with a convectively
enhanced jet streak shifting out of the Ozark Plateau into the
Mid-MS Valley providing solid upper-level divergence/outflow to
maintain the complex in approaching diurnal minima of instability.

With the exiting upper-level support, low level rear(westerly)
inflow is isentropically ascending from north to south allowing
for redevelopment while maintaining placement of back-building
environment.  This is allowing for some stationary tendrils of
ascent with downshear repeating elements, ingesting solidly
unstable, moist air with MUCAPE still over 2000 J/kg and solid
moisture flux convergence to maximize PWat loading over 2".  As
such, rates have been remaining in that 1.5-2"/hr rates with a few
hours likely to occur as the complex becomes cold pool dominant.

RAP analysis denotes, pool of instability remains along and north
of the Red River with a minimum over north Texas and downstream
into northern LA.  With 20-25kts of southwesterly becoming more
westerly across S OK and broadening 500-1000 thickness fields
across S AR/NE TX/N LA; propagation should be initially south the
west-southwest bringing the upwind edge into south-central
TX/central North Texas while downstream convection in AR slowly
weakens in place near the effective cyclonic rotor of the MCS. 
This will allow for some remaining 2-4" totals in SW AR until pool
of instability is exhausted.  Forward propagation to the
west-southwest should limit localized totals, but given the direct
inflow and ample deep moisture intense instantaneous rates and
localized 2-3" totals in 60-90 minutes remains possible with an
isolated 4" across the Red River Basin through the remainder of
the morning as the complex weakens due to decreasing inflow
strength and reducing instability overall.   This generally
follows the 06z NAM-Nest and recent RRFS evolution.

Hydrologically, these instantaneous rates and 2-4" totals are at
the limits of the naturally higher FFG values in the region which
remain around 2-2.5"/hr and 3-4"/3hrs, as such, localized flash
flooding remains possible but likely going to be limited in
coverage given the eventual forward speeds with best opportunity
along the anticyclonic (SE OK to south-central OK) and cyclonic
rotor/bookend circulation (SW AR).

Gallina

ATTN...WFO...FWD...LZK...OUN...SHV...TSA...

ATTN...RFC...FWR...ORN...TUA...NWC...

LAT...LON   35649534 35629470 35379443 34899414 34519344 
            33969338 33589365 33189451 32999530 32939621 
            33039732 33289805 33859828 34369788 35269645 
            
$$
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