Flash Flood Guidance
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774
AWUS01 KWNH 202047
FFGMPD
TNZ000-KYZ000-MOZ000-ARZ000-210246-

Mesoscale Precipitation Discussion 0770
NWS Weather Prediction Center College Park MD
447 PM EDT Tue Aug 20 2019

Areas affected...Southern Missouri into Arkansas and east into
Tennessee

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

Valid 202046Z - 210246Z

SUMMARY...The southwest end of a redeveloped line of thunderstorms
over southern Missouri poses a possible flash flood risk into the
evening as it becomes more oriented with the storm motion.

DISCUSSION...The southward portion of a long-lived mesoscale
convective system has rapidly redeveloped over southeastern MO and
southern IL as it tracks into the Mid-South states. This activity
is developing in an airmass with 3000 to 4000 J/Kg MLCAPE and 2
inch PWATs which is 1.5 standard deviations above normal. This
line will continue to progress south-southeast with light deep
layer mean flow. The western tail of this line is becoming
oriented more northwest to southeast, parallel to the mean layer
flow, which raises the risk for training cells. Therefore the
greatest flash flood threat into the evening is over south-central
MO into northeast AR. This threat is similar to the west end of
the previous line that stalled over far northwest MO and produced
around 3 inches in about an hour.

One hour flash flood guidance is relatively high in this area
which has generally seen below normal rainfall in the past week.
However, given the Ozark terrain of this area and potential for
cell training, a possible flash flood risk is present into the
evening.

Jackson

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

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

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

LAT...LON   37679109 37439025 36918951 36588946 36178940
            35658954 35259009 35229086 35359172 35579249
            35939323 36409354 36979347 37649242



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