392
AWUS01 KWNH 011642
FFGMPD
ARZ000-TXZ000-OKZ000-012030-

Mesoscale Precipitation Discussion 0204
NWS Weather Prediction Center College Park MD
1242 PM EDT Wed May 01 2024

Areas affected...Southeast Oklahamoa...Southwest Arkansas...

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

Valid 011640Z - 012030Z

SUMMARY...Continuing localized flash flooding risk into early
afternoon hours related to persistent moisture convergence near
meso-low.

DISCUSSION...Active warm-advection thunderstorms that developed
due to orthogonal isentropic ascent over last night`s outflow
boundary in the wake of decayed MCS across south-central Oklahoma
continue to persist into southeast Oklahoma with a recent uptick
in downstream thunderstorms.  The morning`s complex supported a
weak surface low to develop along the outflow boundary and based
on 16z analysis is around Atoka county, OK.  Surface to boundary
layer wind response has provided an ample amount of additional
warm advective FGEN ascent downstream across southeast OK.  GOES-E
Visible imagery and surface temperatures denote that ample solar
heating has occurred with temps into the upper 70s/low 80s
along/ahead of the wave to maintain positive buoyancy for stronger
thunderstorms and with mid 60s to low 70 Tds and CIRA sfc to 700mb
layers noting above average moisture steaming to the area to
support 1.5-2"/hr rates.  New development also has a favorable
orientation to deeper layer steering flow to allow for increased
duration for the potential for spots of 1.5-3" additional rainfall
across southeast OK into southwest AR.

If there is a positive to this scenario unfolding, is the area of
concern aligns with a small area that has remained unaffected by
recent heavy rainfall over the past week or so.  AHPS values for
7-14 rainfall anomalies are about 50-75% of normal versus further
west.  Still, the intensity of rates near 2" for 1-2 hours pushes
the even the higher FFG values in the area (2-2.5"/1hr and
2.5-3.5"/3hr).  As such, a localized spot or two of flash flooding
may be possible over the next 2-3 hours, but duration is also
quite uncertain as model guidance has been persistent on weakening
the cells, but they are maintained given stronger than forecast
low level flow and moisture flux (unresolved stronger meso-low).

Gallina

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

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

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

LAT...LON   35159367 35089258 34519215 33819238 33509316
            33739446 33889523 34179620 34809623 35069531