AWUS01 KWNH 041535
FFGMPD
ILZ000-MOZ000-ARZ000-042133-

Mesoscale Precipitation Discussion 1122
NWS Weather Prediction Center College Park MD
1034 AM EST Mon Nov 04 2024

Areas affected...Northern AR...South-Central to Southeast
MO...Southwest IL

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

Valid 041533Z - 042133Z

SUMMARY...Additional rounds of heavy showers and thunderstorms
which will occasionally repeat over the same area will continue to
foster areas of flash flooding heading into the afternoon hours.

DISCUSSION....GOES-E IR satellite imagery in conjunction with
dual-pol radar shows a fairly large broken area of heavy showers
and thunderstorms impacting portions of northern AR through
southeast MO and a small part of southwest IL. The activity
continues to be strongly influenced by enhanced warm air
advection/isentropic ascent and moisture transport across the
region with deep layer southerly flow in place out ahead of a deep
layer trough/closed low gradually ejecting east out of the
southern Rockies.

A southerly low-level jet of 40 to 50 kts in the 850/925 mb layer
is noted in the latest VWP data across central to northern AR and
across southeast MO and southern IL which is acting as a conduit
for the poleward transfer of Gulf of Mexico moisture. PWs across
the region are locally as high as 1.75 inches which are on the
order of 2 to 3+ standard deviations above normal for this time of
the year. This anomalous moisture environment will continue to
favor a well-defined excessive rainfall threat with enhanced
rainfall rates given the warm air advection and proximity of at
least modest instability.

MUCAPE values are on the order of 500 to 1000 J/kg up across
northern AR through southeast MO and this is supporting a largely
elevated convective environment at this time. Some increase in
instability is expected going through mid-afternoon and this
should favor some increase in the rainfall rates which will be
capable of reaching 1 to 2 inches/hour with the stronger storms.

Going through the mid-afternoon hours, additional rainfall totals
of 2 to 4 inches will be possible, with the heaviest totals most
likely over south-central to southeast MO based on the latest 12Z
HREF guidance. The very wet/saturated antecedent conditions that
are in place coupled with the arrival of additional rounds of
heavy rain over the same area will continue to promote additional
areas of flash flooding with locally considerable runoff concerns.

Orrison

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!6GXloCu9o8ZI23AqUpAPdrA1vlbzXXVEvhxpVyv55LOvfXK-763HvBckSdXnu4BCvxz1=
AIF6aQnKNba119zkyBfpiPA$  for graphic product...

ATTN...WFO...LSX...LZK...MEG...PAH...SGF...TSA...

ATTN...RFC...ABRFC...LMRFC...MBRFC...NCRFC...NWC...

LAT...LON   38619040 38578962 37988941 37109001 36469070=20
            35479239 35129354 35689421 36669363 37929201=20
=20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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