Mesoscale Precipitation Discussion 0620
NWS Weather Prediction Center College Park MD
814 AM EDT Thu Aug 09 2018

Areas affected...Northeastern TX...Southeastern OK...Northern
MS...Southern AR

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

Valid 091215Z - 091500Z

Summary....Training precipitation is expected to continue. 
Additional heavy amounts with flash flooding are possible.

Discussion...Deep southwesterly flow ahead an approaching
shortwave continues to tap deeper moisture, drawing it north
across an east-west oriented outflow boundary extending along the
Arkansas-Louisiana border back into northeast Texas - supporting
training precipitation across the highlighted region.  Instability
across the area is limited, however forecast soundings from the
latest runs of the HRRR show deep saturation from the surface
through the mid levels and PWs over 2.0 inches - supporting
efficient rainfall processes.  Latest radar imagery from KSHV and
KLZK continue to show localized areas with rainfall rates of 1.0
in/hr moving east across the region.  Overnight hi-res models, as
well as recent runs of the HRRR show the potential for locally
heavy amounts continuing into the late morning hours.  For the
3-hr period ending at 15 UTC, 40km neighborhood probabilities from
the 06 UTC HREF are greater than 50 percent for amounts over an
inch across much of highlighted area. Overall, flash flood
guidance values are relatively high across the region; however
there are some areas in southeast Arkansas where 3-hr values have
decreased to as low as 0.75 - suggesting heightened runoff
concerns should additional heavy amounts occur.

Pereira

ATTN...WFO...JAN...LZK...MEG...SHV...

ATTN...RFC...ABRFC...LMRFC...SERFC...

LAT...LON   35099081 34868872 34088868 33808957 33719013
            33539209 33139372 33249501 34179451 34979255