571
FXUS64 KMRX 211826
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
226 PM EDT SUN JUN 21 2026
..NEW DISCUSSION
KEY MESSAGES
UPDATED AT 226 PM EDT SUN JUN 21 2026
- SHOWERS AND STORMS ARE LIKELY ON MONDAY, WITH THE POTENTIAL FOR
STRONG/SEVERE STORMS IN THE AFTERNOON/EVENING. MULTIPLE ROUNDS ARE
POSSIBLE AND TIMING REMAINS UNCERTAIN.
- DRY WEATHER TUESDAY AND WEDNESDAY, THEN DAILY RAIN CHANCES
RETURN LATE IN THE WEEK, WITH TEMPERATURES NEAR NORMAL.
DISCUSSION
ISSUED AT 226 PM EDT SUN JUN 21 2026
THE REMNANTS OF THE ONGOING CONVECTION/MCS OVER MO/IL WILL REACH OUR
AREA LATE TONIGHT. OVER THE LAST SEVERAL RUNS, MODELS HAVE BEEN IN
POOR AGREEMENT AND SHOWN POOR CONSISTENCY WITH THE TIMING AND
INTENSITY OF THE REMNANT CONVECTION AS IT NEARS OUR AREA. WE CAN
GENERALLY EXPECT THAT A 4-8 AM TIME FRAME IS LIKELY FOR SHOWERS IN
OUR NORTHERN PLATEAU COUNTIES, AND THAT A SEVERE THREAT IS UNLIKELY
AS THE APPROACHING COLD POOL OUTFLOW ENCOUNTERS AN UNFAVORABLE
ENVIRONMENT IN EAST TN. ANY SHOWERS/STORMS WILL BE ELEVATED WITH
WEAK LAPSE RATES ALOFT, AND LIKELY WON'T LAST VERY FAR PAST I-75.
AS WE HAVE DISCUSSED THE LAST SEVERAL DAYS, THE QUESTION REMAINS HOW
THIS MORNING ACTIVITY WILL AFFECT A SECOND ROUND OF SHOWERS/STORMS
AHEAD OF THE COLD FRONT IN THE AFTERNOON/EVENING. AGAIN, MODEL
AGREEMENT/CONSISTENCY ON THE DETAILS HAS BEEN POOR, BUT THE
DEPICTION OF ANOTHER ROUND OF STRONGER SHOWERS/STORMS CONTINUES FOR
MONDAY AFTERNOON, POSSIBLY TWO ROUNDS ACCORDING TO THE HRRR. DURING
THIS TIME, HREF PROBABILITIES OF CAPE > 1000 J/KG AND SHEAR > 25 KT
ARE IN THE 25-50% RANGE - NOT SUPER IMPRESSIVE AT ALL BUT ADEQUATE
FOR A FEW STRONG TO SEVERE STORMS. A 35-40 KT LLJ COULD MIX DOWN
WITH DOWNBURSTS. 0-3 KM SHEAR IS MOSTLY UNI-DIRECTIONAL BUT ANY
BOUNDARIES THAT INTERACT WITH STORMS COULD LEAD TO A BRIEF AND
ISOLATED TORNADO, MAINLY IN SOUTHERN SECTIONS. THE FLASH FLOOD
THREAT REMAINS AS TRAINING CELLS IN THE UNI-DIRECTIONAL FLOW COULD
CAUSE PROBLEMS, BUT THE PROGRESSIVE MOVEMENT OF STORMS IN THE
WESTERLY FLOW SHOULD KEEP THE PROBLEMS ISOLATED, SO NO FLOOD WATCH
APPEARS NECESSARY AT THIS TIME. TIMING APPEARS TO BE 2-10 PM FOR
MOST OF THE STORMS ALONG A PRE-FRONTAL TROUGH AND UPPER DIVERGENCE
MAXIMUM, WITH A CHANCE OF SHOWERS PERSISTING OVERNIGHT UNTIL THE
SURFACE FRONT PUSHES THROUGH TUESDAY MORNING. NBM POPS APPEAR WAY
TOO HIGH FOR THE POST-FRONTAL AND NW FLOW ENVIRONMENT ON TUESDAY,
AND WILL BE CUT BACK.
WEDNESDAY WILL BE DRY WITH A LARGE SURFACE HIGH COVERING THE CENTRAL
AND SOUTHERN APPALACHIANS, AND A BUILDING MIDLEVEL RIDGE FROM THE
WEST. A LOW PRESSURE SYSTEM TRACKING ACROSS THE UPPER MIDWEST AND
GREAT LAKES BRINGS RAIN CHANCES BACK TO THE AREA ON THURDAY. A BROAD
TROUGH OVER THE EASTERN CONUS THROUGH THE WEEKEND COULD BRING A FEW
DISTURBANCES TO THE AREA, SO LOW CHANCE POPS WILL BE IN THE FORECAST
EACH DAY.
AVIATION
(18Z TAFS)
ISSUED AT 110 PM EDT SUN JUN 21 2026
VFR CONDITIONS AND WINDS LESS THAN 10 KT FROM THE SW WILL CONTINUE
THROUGH THE AFTERNOON AND EVENING. CLOUDS ARE EXPECTED TO INCREASE
LATE TONIGHT, LIKELY IN THE MVFR-VFR MARGINS. CHA APPEARS MOST
LIKELY TO HAVE MVFR CIGS, WITH LOWER CHANCES AT TYS AND EVEN LOWER
AT TRI. SOME GUSTY SW WINDS ARE EXPECTED TO DEVELOP LATE THIS TAF
PERIOD AT TYS AND TRI, MAINLY 20-25 KT GUSTS.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 73 87 70 85 / 30 80 70 10
KNOXVILLE MCGHEE TYSON AIRPORT, TN 72 86 68 82 / 30 90 80 10
OAK RIDGE, TN 71 85 67 83 / 50 90 60 0
TRI CITIES AIRPORT, TN 66 85 65 80 / 10 80 90 20
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
DISCUSSION...DGS
AVIATION...DGS
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