Mesoscale Precipitation Discussion 0144...Corrected
NWS Weather Prediction Center College Park MD
532 AM EDT Wed Apr 10 2024

Corrected for minor northeastward expansion of MPD area

Areas affected...southeastern TX into central/southern LA and
southwestern MS

Concerning...Heavy rainfall...Flash flooding likely

Valid 100927Z - 101430Z

Summary...Heavy rain is expected to expand eastward into portions
of south-central LA with scattered to numerous areas of flash
flooding through 14Z, some of which could be considerable to
severe with life-threatening impacts.

Discussion...A persistent area of training from the southern Piney
Woods region of TX into western LA has resulted in an areas of 5
to 10+ inches of rain over the past 12 hours, extending from
Hardin and Tyler counties into western Vernon and Beauregard
parishes. Radar imagery at 09Z showed the west to east axis of
training, occurring just north of a combined outflow/stationary
front, has begun to lift north over the past hour, ahead of an
approaching, forward propagating convective line moving east from
a Conroe to Houston to Freeport line. The VAD wind profile from
KHGX at 09Z indicated southerly winds of 30-40 kt in the 2-5 kft
AGL layer, ahead of the convective line, a 10 kt increase since
two hours earlier. The strengthening low level flow, just ahead of
a surface low and southward extending cold front near Houston, has
likely helped to shift the axis of ongoing training to the north
over the past hour.

As a potent mid-level trough over western TX continues to advance
east this morning, increased large scale ascent (including
strengthening divergence and diffluence aloft) will shift eastward
from eastern TX into western LA. An ongoing axis of elevated
convergence in the 925-850 mb layer, crossing the Sabine River
from SW to NE, is likely to be disrupted as the upper trough and
preceding convective line advance eastward this morning.
Overrunning low level flow of 30-40 kt will translate eastward
into LA over the next few hours, tapping a notable region of 1000
to 2000+ J/kg MLCAPE located off of the upper TX and LA coast,
supporting continued heavy rainfall. Mean steering flow will be
oriented from SW to NE, but west to east mean translation of the
heavy rainfall axis is expected which should result in continued
training, with rainfall rates of 1-2 in/hr, locally 2 to near 3
in/hr. Additional rainfall totals of 3-5 inches (locally higher)
are expected through 14Z, which is likely to extend a significant
flash flood threat eastward from southeastern TX into portions of
central/southern LA. Any overlap of heavy rain which has fallen
over the past 12 hours will maintain a risk of considerable or
major flash flooding with the Sabine River Valley, and possibly
eastward into portions of central or south-central LA.

Otto

ATTN...WFO...HGX...JAN...LCH...LIX...SHV...

ATTN...RFC...LMRFC...WGRFC...NWC...

LAT...LON   32199146 31869063 31259029 30558992 30158962
            29798980 29609040 29729173 29739326 29509480
            29789521 30389498 31029423 31419344