927
ACUS11 KWNS 201734
SWOMCD
SPC MCD 201734
TNZ000-KYZ000-201930-
MESOSCALE DISCUSSION 0803
NWS STORM PREDICTION CENTER NORMAN OK
1234 PM CDT WED MAY 20 2026
AREAS AFFECTED...PORTIONS OF MIDDLE/EASTERN TENNESSEE INTO SOUTHERN
KENTUCKY
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 201734Z - 201930Z
PROBABILITY OF WATCH ISSUANCE...20 PERCENT
SUMMARY...WIDELY SCATTERED THUNDERSTORMS MAY POSE A RISK FOR
ISOLATED DAMAGING WIND GUSTS AND SMALL TO MARGINALLY SEVERE HAIL
THROUGH THIS EVENING. WATCH ISSUANCE IS UNLIKELY AT THIS TIME.
DISCUSSION...RECENT RADAR IMAGERY DEPICTS INCREASING THUNDERSTORM
COVERAGE ACROSS PORTIONS OF MIDDLE/EASTERN TENNESSEE AND SOUTHERN
KENTUCKY AMID CONTINUED DIURNAL HEATING OF A MOIST LOW-LEVEL AIR
MASS (DEWPOINTS IN THE MID/UPPER 60S F). LATEST OBJECTIVE ANALYSIS
DEPICTS ONLY WEAK BUOYANCY ACROSS THE REGION, WITH MLCAPE AROUND 500
J/KG. FURTHER DESTABILIZATION IS EXPECTED THROUGH PEAK HEATING THIS
AFTERNOON, A MODIFIED 12Z BNA OBSERVED SOUNDING SUGGESTING THAT
MLCAPE IS LIKELY APPROACHING 1000 J/KG BASED ON RECENT SURFACE
OBSERVATIONS.
WHILE DEEP-LAYER FLOW REMAINS WEAK ACROSS THE REGION (LESS THAN 30
KTS OF FLOW SAMPLED THROUGH THE COLUMN BY THE LATEST OHX VWP), 20-25
KTS OF EFFECTIVE SHEAR SHOULD BE SUFFICIENT TO SUPPORT MODEST
UPDRAFT ORGANIZATION INTO A MULTICELLULAR STORM MODE. IN CONJUNCTION
WITH STEEPENING LOW-LEVEL LAPSE RATES, THIS MAY PROMOTE THE
POTENTIAL FOR GUSTY TO ISOLATED DAMAGING WIND GUSTS (LIKELY IN THE
40-50 MPH RANGE) WITH ANY STRONGER, MORE WELL-ORGANIZED CLUSTERS.
ISOLATED SMALL TO MARGINALLY SEVERE HAIL MAY ALSO ACCOMPANY THE MOST
ROBUST UPDRAFTS DESPITE POOR MID-LEVEL LAPSE RATES (5.5-6.0 C/KM PER
LATEST MESOANALYSIS). GIVEN THE EXPECTATION FOR SEVERE
COVERAGE/MAGNITUDE TO REMAIN LIMITED, WATCH ISSUANCE IS UNLIKELY AT
THIS TIME.
..CHALMERS/HART.. 05/20/2026
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...MRX...JKL...LMK...OHX...HUN...
LAT...LON 35788453 35418508 35058572 35018638 35208688 35548695
35958683 36358658 37218594 37588530 37558493 37368442
37068389 36748381 36258391 35788453
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
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