493
FXUS64 KMRX 111740
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
140 PM EDT THU JUN 11 2026
..NEW DISCUSSION, AVIATION
KEY MESSAGES
UPDATED AT 137 PM EDT THU JUN 11 2026
- PRETTY HIGH RISK OF SEVERE STORMS AREA WIDE TOMORROW. DAMAGING
WINDS ARE THE MOST LIKELY HAZARD, AND COULD BE QUITE STRONG
(POSSIBLY AS HIGH AS 80MPH). HAIL AND FLASH FLOODING ARE ALSO A
CONCERN.
- UNSETTLED PATTERN CONTINUES THROUGH THE MIDDLE OF NEXT WEEK.
DISCUSSION
ISSUED AT 137 PM EDT THU JUN 11 2026
THE PRIMARY CONCERN FOR THE NEXT FEW DAYS IS THE CHANCE OF SEVERE
STORMS TOMORROW AFTERNOON ACROSS OUR FORECAST AREA. AS SUCH, THE
DISCUSSION WILL FOCUS ON THAT ALMOST EXCLUSIVELY.
SHORTWAVE ENERGY WILL MOVE FROM THE CENTRAL PLAINS TO THE WESTERN
GREAT LAKES REGION TODAY AND TONIGHT, DRIVING A COLD FRONT
SOUTHEASTWARD TOWARDS THE SOUTHERN APPALACHIAN REGION TOMORROW.
AHEAD OF THE FRONT, WIDESPREAD CONVECTION EXPECTED ACROSS THE
MIDWEST LATER ON THIS AFTERNOON. THIS ACTIVITY WILL LAY OUT AN
OUTFLOW BOUNDARY THAT WILL BE PUSHING INTO THE CUMBERLAND PLATEAU
TOMORROW AFTERNOON, SPARKING OFF WIDESPREAD STRONG TO SEVERE STORMS
ACROSS EAST TENNESSEE. THERE ARE SOME TIMING UNCERTAINTIES HERE, AND
POTENTIAL FAILURE MODES, BUT IT APPEARS LIKELY THAT WE SEE VERY
STRONG/SEVERE STORMS TOMORROW CAPABLE OF DAMAGING WINDS A BIT HIGHER
THAN WHAT WE'D NORMALLY EXPECT IN THIS AREA.
HAZARDS:
TOMORROW LOOKS PRIMARILY LIKE A DAMAGING WIND THREAT. HOWEVER, THERE
IS ALSO A THREAT OF SEVERE SIZED HAIL AS WELL AS FLASH FLOODING.
THEY'RE LESS A THREAT THAN DAMAGING WINDS BUT I CAN'T IGNORE THEM.
THE TORNADO RISK LOOKS NEGLIGIBLE DUE TO LACK OF SHEAR. GOING BACK
TO THE DAMAGING WIND THREAT, THE MODEL CONSENSUS SEEMS TO BE THAT
SURFACE BASED CAPE VALUES WILL EXCEED 2,500 - 3,000 J/KG TOMORROW
AFTERNOON. THIS IS BACKED BY ROUGHLY A 70-80 PERCENT CHANCE IN
PROBABILISTIC GUIDANCE OF EXCEEDING 2,000 J/KG SFC CAPE. MEANWHILE,
DOWNDRAFT CAPE LOOKS TO EXCEED 1,000 J/KG, WITH PLENTY OF MID LEVEL
DRY AIR INTRUSION AND VERY STRONG LAPSE RATES. LACK OF SHEAR
(EFFECTIVE BULK SHEAR VALUES OF LESS THAN 15-20KT) MEANS THAT THE
INITIAL CONVECTIVE MODE WILL LIKELY WIND UP BEING CELLULAR OR
MULTICELL CLUSTERS, BUT THIS MAY TRANSITION INTO SOME QUASI-LINEAR
STATE LATER IN THE EVENING AS CONVECTION BECOMES MORE WIDESPREAD. AS
SUCH, THE DAMAGING WIND RISK WILL BE SPORADIC INITIALLY. I'D EXPECT
THE POTENTIAL FOR 70-80MPH WINDS GIVEN THE INSTABILITY AND RESULTING
STORMS HEIGHTS WE'LL BE DEALING WITH. SPEAKING OF INSTABILITY AND
STORM HEIGHTS, LET'S TALK ABOUT HAIL. THE LACK OF SHEAR MEANS LESS
ORGANIZED CONVECTION WHICH WILL WORK AGAINST SEVERE SIZED HAIL, AS
WILL THE FAIRLY HIGH FREEZING LEVELS. BUT THE FORECAST INSTABILITY
MEANS THERE'S AT LEAST A MENTIONABLE RISK OF SOME SEVERE SIZED HAIL.
I WOULD NOT BE SURPRISED TO SEE SOME 1" HAIL REPORTS OF PERHAPS
SLIGHTLY LARGER.
AS FOR THE HEAVY RAIN AND FLASH FLOODING THREAT, THIS SHOULD BE
ISOLATED BUT IT CERTAINLY EXISTS. PWATS ARE HIGH, AND THE STRONG TO
SEVERE NATURE OF STORMS TOMORROW MEANS THAT HEAVY RAINFALL RATES
WILL BE POSSIBLE. THE LIMITING FACTOR I THINK WILL BE THE LIFESPAN
OF ANY GIVEN STORM AND WHETHER OR NOT WE HAVE ANY TRAINING EFFECTS.
MEAN WINDS AREN'T PERFECTLY ALIGNED WITH THE INCOMING OUTFLOW
BOUNDARY AND FRONT, BUT THEY'RE CLOSE, WHICH MAY SUPPORT SOME
TRAINING EFFECTS. LACK OF SHEAR MEANS THAT STORM LIFESPANS WILL BE
SHORTER (MORE ON THE SUMMERTIME CELLULAR END OF THE SPECTRUM VERSUS
SUPERCELLS) SO I THINK THAT WE'LL NEED SOME DEGREE OF TRAINING
EFFECTS TO REALLY GET ANY SIGNIFICANT FLOODING.
TIMING AND UNCERTAINTIES:
CURRENT TIMING FAVORS STORM INITIATION OVER THE NORTHERN CUMBERLAND
PLATEAU AROUND 2-3 PM EDT ROUGHLY. I LUMP TIMING AND UNCERTAINTIES
IN TOGETHER HERE BECAUSE STORM INITIATION IS ALMOST CERTAINLY GOING
TO BE ALONG THE INCOMING OUTFLOW BOUNDARY AND THERE IS SOME
DISAGREEMENT ON WHEN THAT MAKES IT IN AND EXACTLY WHEN/WHERE STORMS
INITIATE. MOST GUIDANCE FAVORS IT ARRIVING IN THE PLATEAU DURING
THAT 2-3 PM EDT WINDOW, WITH STORM INITIATION OCCURRING AT THAT
TIME. BUT SOME GUIDANCE HAS INITIATION OCCURRING SQUARELY IN THE TN
VALLEY AND IT DOING SO A COUPLE OF HOURS LATER. THE PLATEAU
OFTENTIMES CONVECTS AS EARLY IN THE AFTERNOON AS THE HIGHER TERRAIN
OF THE SMOKIES DOES, SO I WOULD EXPECT THAT EARLY AFTERNOON TIME TO
BE THE MOST LIKELY. MOST GUIDANCE MOVES STORMS OFF TO OUR SOUTHEAST
BY 9-10 PM EDT AS WELL, SO IT WON'T LINGER INTO THE OVERNIGHT HOURS.
AS FOR THE REMAINDER OF THE FORECAST PERIOD, THIS FRONT PUSHES SOUTH
OF US ON SATURDAY. WE MAY GET A REPRIEVE FROM THE HUMIDITY IN THE
NORTHERN AREAS, AND ALSO SOME DRY CONDITIONS THAT DAY, BUT AN
INCOMING SHORTWAVE IN THE ZONAL FLOW ALOFT MAY SPARK OFF SOME
ADDITIONAL STORMS AT LEAST NEAR/SOUTH OF THE I-40 CORRIDOR. BETTER
CHANCES EXIST ON SUNDAY THOUGH AS ANOTHER, STRONGER IMPULSE MOVES
THROUGH. MOVING INTO EARLY NEXT WEEK, UPPER FLOW BECOMES SELY OVER
THE DEEP SOUTH AND SOUTHERN APPALACHIAN REGION MONDAY THROUGH
WEDNESDAY. WE'LL CONTINUE TO MONITOR THIS AS THIS PATTERN WILL
SUPPORT WIDESPREAD HEAVY RAINS AND THE POTENTIAL FOR FLOODING. THE
QUESTION IS REALLY, WHERE WILL THAT SET UP. THERE REMAINS QUITE A
BIT OF UNCERTAINTY THERE. CURRENT TRENDS SHOW THE HEAVY RAINS
STAYING MOSTLY TO OUR SOUTH, BUT WE'RE CLOSE ENOUGH TO KEEP AN EYE
ON IT.
AVIATION
(18Z TAFS)
ISSUED AT 137 PM EDT THU JUN 11 2026
WE DO HAVE SOME ISOLD SHRA IN THE TN VALLEY THIS AFTERNOON, ONE OF
WHICH WAS NEAR KTYS AS OF THE WRITING OF THIS. THREW IN SOME VCSH
AT TYS AND CHA TO ACCOUNT FOR CURRENT RADAR TRENDS BUT THOSE
SHOULD DIE OFF IN THE NEXT COUPLE OF HOURS. OTHERWISE, VFR FLIGHT
CATEGORIES SHOULD PREVAIL THROUGH THE 18Z PERIOD. WIDESPREAD
SHRA/TSRA WILL BE MOVING INTO THE TN VALLEY SHORTLY AFTER THE END
OF THE PERIOD THOUGH.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 73 91 71 90 / 0 60 20 10
KNOXVILLE MCGHEE TYSON AIRPORT, TN 73 91 69 88 / 0 80 40 10
OAK RIDGE, TN 71 90 66 87 / 0 80 20 0
TRI CITIES AIRPORT, TN 70 90 65 87 / 10 80 50 10
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
DISCUSSION...CD
AVIATION...CD
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