Mesoscale Precipitation Discussion 0881
NWS Weather Prediction Center College Park MD
858 AM EDT Sat Sep 22 2018

Areas affected...Northeast TX towards the OK/AR/LA border

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

Valid 221257Z - 221757Z

Summary...Flash flooding is possible this morning across portions
of Northeast TX into far southeast OK, northwest LA and southwest
AR.

Discussion...An area of low pressure continues to slowly move
eastward just south of the Red River over north TX. A nearly
stationary front extends east from the low across northeast TX
towards the AR/LA border. An area of convection is moving
northward ahead of this low this morning. This activity is
generally progressive off to the north, however could see some
slowing and backbuilding of the activity as it interacts with the
west/east axis of strong low level convergence. The environment
remains conducive for warm rain processes. Thus while activity
should remain progressive enough to prevent extreme totals...given
the expected rainfall efficiency and some backbuilding
potential...at least localized 2-4" totals appear probable across
portions of northeast TX towards the OK/TX/AR/LA border region.
Overall, antecedent rainfall over the past day has not been as
high across this area, so would characterize the flash flood
threat through 18z as POSSIBLE, with significant widespread issues
appearing less likely.

In general would say most of the high res guidance are too far
north with their axis of higher QPF amounts through 18z. The
actual position of the front and instability axis appears further
south than forecast...and is unlikely to make too much progress
northward this morning. Overrunning rainfall is expanding north of
the front across southeast OK this morning...but the lack of
instability should keep rates down. Given the past 24 hour
rainfall over southeast OK, this additional rain may continue
ongoing areal flood issues...but appears less likely  to result in
additional significant flash flood concerns at this time. Thus,
focused the MPD area further southeast where the best chance of
convective rains producing more intense rates appears to exist.

Chenard

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

ATTN...RFC...ABRFC...LMRFC...WGRFC...

LAT...LON   34119435 34119398 33889320 33709278 33339269
            32839290 32199336 32059392 32169498 32369558
            32929620 33009627 33249658 33529707 33689711
            33779623 33839542 33999477