169
FXUS64 KMRX 212356
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
756 PM EDT SUN JUN 21 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 744 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 THURSDAY. 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
(00Z TAFS)
ISSUED AT 744 PM EDT SUN JUN 21 2026
VFR CAN GENERALLY BE EXPECTED FOR THE NEXT 9 HOURS OR SO. MVFR CIG
MAY REACH CHA NEAR SUNRISE BEFORE POSSIBLE PRECIPITATION MOVES
IN. STILL SOME UNCERTAINTY, BUT REMNANTS FROM AN MCS MAY OR MAY
NOT MAKE IT TO THE AREA EARLY TOMORROW MORNING. TO REFLECT THE
CHANCE, ADDED PROB30 AT ALL TERMINALS UNTIL LATE MORNING.
THERE COULD BE A BRIEF PERIOD OF DRY CONDITIONS AND LOW VFR CIG
BEFORE AFTERNOON AND EVENING CONVECTION ALONG A FRONT ARRIVES.
ALSO SOME UNCERTAINTY WITH HOW STRONG STORMS COULD GET IF
IMPACTED BY MORNING ACTIVITY. EITHER WAY, AFTERNOON VCTS AND
PROB30 FOR TSRA ADDED FOR LAST 6 HOURS OF THE TAF PERIOD. MVFR
WILL MOST LIKELY PREVAIL WITH TEMPORARY DIPS TO IFR UNDER ANY
HEAVY STORM. SWLY WINDS EXPECTED TO INCREASE AFTER SUNRISE,
CREATING GUSTS UP TO 25 KT AT TYS AND TRI.
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...KS
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