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Severe Center
Mesoscale Precipitation Discussion #0165 - Heavy Rainfall 
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Mesoscale Precipitation Discussion 0165
NWS Weather Prediction Center College Park MD
512 AM EDT Sat May 09 2026

Areas affected...central/southern Louisiana, southern Mississippi,
southern Alabama, and far western Florida Panhandle

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

Valid 090912Z - 091512Z

Summary...Areas of convection (with scattered
mergers/backbuilding) will pose a flash flood risk through 15Z/10a
Central this morning.

Discussion...Scattered convection has organized into a mix of
clusters and linear segments along a couple axes -- one extending
from near Natchitoches, LA to Jackson, MS to west-central AL and
another, more scattered band from near Natchez, MS to near
Slidell, LA. These cells were moving eastward at an appreciable
clip (30-35 kt), but were being sustained by appreciable mid-level
instability and 1.75 inch PW values. The loosely organized nature
of the cells was supporting occasional training and mergers, with
spots of 1-2.5 inch/hr rain rates focused primarily in northern
Louisiana over the past half hour to hour. FFGs in this region
were high (around 3-4 inch/hr), suggestive of only an isolated
flash flood risk (at best) in the short term.

With time, cells will migrate/evolve east-southeastward toward
portions of southern Mississippi that have received 3-6 inches of
rainfall over the past 72 hours. Soil moistures are wetter here,
and FFGs are somewhat lower (near 2 inches/hr in spots). Portions
of southern Louisiana have lower FFGs from prior rain (around 1
inch/hr) as well. The slow northward drift of a remnant outflow
from earlier convection (and attendant surface-based instabilty)
will probably interact with ongoing convection favorably for more
mergers and localized training as cells migrate
east-southeastward, with rain rates over 2 inch/hr expected in a
few spots (supported by abundant PW values). Areas of flash
flooding are possible, and the overall risk will increase in the
aforementioned areas (esp. southern LA/MS) between 10Z-15Z this
morning.

Cook

ATTN...WFO...BMX...JAN...LCH...LIX...MOB...SHV...TAE...

ATTN...RFC...ALR...FWR...ORN...NWC...

LAT...LON 32938887 32498711 32278640 31948583 31048582
30548756 30058985 30019105 30469219 30889319
32419374 32689303 32649166 32769048