626
AWUS01 KWNH 052113
FFGMPD
FLZ000-ALZ000-MSZ000-LAZ000-060200-

Mesoscale Precipitation Discussion 0567
NWS Weather Prediction Center College Park MD
512 PM EDT Fri Jul 05 2024

Areas affected...Southern Mississippi & Alabama & Eastern
Louisiana

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

Valid 052111Z - 060200Z

SUMMARY...Storms that have developed ahead of a cold front are
nearly stationary, and have been producing rain rates over 3
inches per hour. Flash flooding possible.

DISCUSSION...Several areas of storms that have developed this
afternoon across the central Gulf Coast have been merging into
larger complexes. These storms have a history of producing
rainfall rates over 3 inches per hour, due to abundant atmospheric
moisture with PWATs over 2.5 inches from SPC mesoanalysis. SBCAPE
values are peaking near 5,000 J/kg over coastal Mississippi. These
very favorable atmospheric conditions suggest continued
maintenance of the ongoing convection. Since this main complex of
storms is well out ahead of a southward moving cold front
approaching the LA/AR border, they will have plenty of time to
remain in place and potentially cause flash flooding over the
impacted areas. FFGs in this area are very high, generally at or
above 3 inches per hour and 4 inches per 3-hours. Thus, only the
strongest and most stationary storms will be strong enough to
produce flash flooding. However, given the aforementioned near
record atmospheric moisture in place for these storms to feed
on...these rates of rainfall are possible. Thus, flash flooding is
possible.

CAMs guidance has been handling the convective evolution in this
area fairly well, and suggests that the storms generally along the
line that follows the east-west-oriented LA/MS border will
gradually creep southward, and may impact Mobile and New Orleans
over the coming hours. Significant flash flooding would be
possible should 3 inch per hour rates occur over those respective
metros. Additional storms associated with the cold front may form
in areas hit with the current convection north of the primary line
over south-central MS and northern LA, which may also result in an
isolated flash flooding threat. With loss of daytime heating this
evening, the convective coverage and intensity should wane,
resulting in a lessening threat for flash flooding.

Wegman

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

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

ATTN...RFC...LMRFC...SERFC...NWC...

LAT...LON   32379243 32179014 32188880 31978810 31868751
            31398731 30618759 30438854 29859005 29979140
            30369272 31449277