Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Sun May 07 2023 18:02:29

AWUS01 KWNH 071802
FFGMPD
TNZ000-KYZ000-INZ000-ILZ000-MOZ000-ARZ000-080000-

Mesoscale Precipitation Discussion 0232
NWS Weather Prediction Center College Park MD
201 PM EDT Sun May 07 2023

Areas affected...southern Illinois, western Kentucky, western
Tennessee, eastern Missouri, and northeastern Arkansas

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

Valid 071800Z - 080000Z

Summary...A complicated mesoscale pattern will ultimately result
in areas of increasing convection and flash flood potential
through 00Z.

Discussion...A remnant outflow boundary continues to migrate
slowly southward and extends from near IJX in western Illinois
south-southeastward through BLV, HSE, and near BWG.  West of this
outflow boundary, nearly full sunshine has resulted in strong
destabilization (3000+ J/kg MLCAPE) and weakening convective
inhibition.  A few thunderstorms have developed west of the
outflow boundary also across southeastern Missouri near POF.=20
These storms are likely tied to heating/insolation and the
eastward advancement of a stout mid-level shortwave trough
centered over Arkansas.  Mid-level temps of -15 to -16C are
gradually migrating eastward in tandem with the mid-level wave,
and should approach the outflow over the next 1-3 hours.

The interaction of the outflow boundary, cooling aloft, and
abundant surface-based instability should allow for robust
convective development to occur through 19-20Z or so.  Slow storm
motions (around 15-25 knots) and locally repeating/redeveloping
convection along the stalling outflow boundary should allow for
areas of prolonged heavy rainfall and potentially 1-2.5 inch/hr
rainfall rates.  FFGs are in that general range - closer to 2-2.5
inches across Kentucky but lower across Illinois (1.5 inch/hr or
so).  These thresholds should be exceeded at times beneath
heavier/more dominant convection this afternoon.

Over time, models/observations suggest a renewed southward
movement of the outflow boundary as cold pools are reinforced by
expanding convective coverage.  This should send the outflow
boundary south into areas of northwestern Tennessee and vicinity
over time - potentially as early as 22Z or so.

Cook

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!9yIITAPaP7loiHf0vhaJ73NT0Iydn9C9NlkP0Vsb8TkAqIq1BJyAluadgy7aZfSBgZ3M=
vRbh8s91zLQQpLgal_lbnSE$  for graphic product...

ATTN...WFO...DVN...ILX...LMK...LSX...MEG...OHX...PAH...

ATTN...RFC...LMRFC...MBRFC...NCRFC...OHRFC...NWC...

LAT...LON   40959045 40668919 39728870 38558813 37668762=20
            37068609 36408619 35578760 35438997 37189083=20
            40219140=20

=3D =3D =3D
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