015
FXUS64 KMRX 011913
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
313 PM EDT SAT AUG 1 2026
..NEW DISCUSSION
KEY MESSAGES
UPDATED AT 245 PM EDT SAT AUG 1 2026
- ADDITIONAL SHOWERS AND STORMS ARE EXPECTED THIS AFTERNOON AND
EVENING. A FEW STORMS MAY BECOME STRONG TO SEVERE, ESPECIALLY
OVER THE PLATEAU AND THE SOUTHERN TENNESSEE VALLEY THIS EVENING.
LOCALIZED FLOODING WILL ALSO BE POSSIBLE.
- ISOLATED DAMAGING WINDS AND FLOODING WILL BE POSSIBLE WITH
ADDITIONAL STORMS ACROSS FAR NORTHEAST TENNESSEE AND SOUTHWEST
VIRGINIA SUNDAY AFTERNOON.
- SCATTERED SHOWERS AND STORMS CAN BE EXPECTED EACH DAY MONDAY
THROUGH FRIDAY, ESPECIALLY DURING THE AFTERNOON HOURS.
DISCUSSION
ISSUED AT 245 PM EDT SAT AUG 1 2026
UPPER LEVEL PATTERN CONSISTS OF A SHORTWAVE DIVING THROUGH
MISSISSIPPI RIVER VALLEY TOWARDS THE OHIO AND TENNESSEE VALLEY
REGION. A WARM FRONT LIFTING THROUGH THE CWA HAS BEEN THE DRIVING
FORCE FOR SHOWERS AND A FEW THUNDERSTORMS THIS MORNING AND EARLY
AFTERNOON. WHILE A FEW ISOLATED SHOWERS CAN BE NOTED BEHIND THE MAIN
RAIN SHIELD, SOME CLEARING IS PRESENT ACROSS PORTIONS OF CENTRAL
TENNESSEE INTO NORTHERN ALABAMA AND ALONG THE CUMBERLAND PLATEAU. A
TRAILING COLD FRONT IS EXPECTED TO PROGRESS THROUGH THE REGION THIS
EVENING, WITH ADDITIONAL SHOWER AND STORM DEVELOPMENT ALONG AND
AHEAD OF THIS FRONT. THERE ARE STILL SOME DISCREPANCIES AMONG CAMS
IN HOW WELL ORGANIZED OR THE EXACT COVERAGE AREA OF CONVECTION ALONG
THIS FEATURE, HOWEVER, ONE TREND THAT CATCHES MY EYE IS THAT OF THE
NAMS.
LATEST SURFACE OBSERVATIONS SHOW TEMPERATURES REBOUNDING INTO THE
LOW TO MID 80S IN THE SOUTHERN VALLEY AND PLATEAU, UPPER 70S ON THE
NORTHERN PLATEAU, BUT REMAINING IN THE LOW 70S IN PORTIONS OF THE
CENTRAL VALLEY AND EASTWARD. THE NAM SEEMS TO DEPICT A TREND IN
STORM COVERAGE THAT BEST ALIGNS WITH WHERE PRECIP HAS LINGERED
LONGEST THIS AFTERNOON... ONE WHERE STORMS THAT DEVELOP OVER MIDDLE
TENNESSEE PERSIST INTO THE PLATEAU, BUT AS THE ACTIVITY PROGRESSES
FURTHER EAST INTO THE CWA, THE FOCUS IS GENERALLY ALONG AND SOUTH OF
I-40 WHERE BETTER DESTABILIZATION OCCURS AMONG HIGHER THETA-E
ADVECTION.
OVERALL, HREF DEPICTS AROUND 1500-2000 J/KG OF MLCAPE AND EFFECTIVE
SHEAR BETWEEN 20 AND 25KTS AS THIS ACTIVITY IS EXPECTED TO TAKE
PLACE. ADDITIONALLY, PWAT WILL BE WELL INTO THE 90TH PERCENTILE.
THIS WILL LEAD TO DAMAGING WINDS AND ISOLATED FLOODING AS THE
PRIMARY HAZARDS. HOWEVER, THE SHEAR IS JUST STRONG ENOUGH THAT A LOW
TORNADO RISK WILL IS IN PLACE, PRIMARILY ALONG THE CUMBERLAND
PLATEAU AND SOUTHERN VALLEY WHERE THE GREATEST DESTABILIZATION HAS
OCCURRED. OF COURSE ANY STORM THAT HAS ENOUGH ROTATION FOR A
POTENTIAL TORNADO COULD ALSO EXHIBIT SMALL HAIL AS WELL. ACTIVITY
WILL GRADUALLY TREND DOWNWARD IN INTENSITY AROUND MIDNIGHT OR
SHORTLY THEREAFTER.
AS WE HEAD INTO SUNDAY AFTERNOON, A FEW ADDITIONAL SHOWERS AND
STORMS MAY DEVELOP ALONG THE SLOWLY PROGRESSING COLD FRONT. LATEST
TREND IN CAMS FAVORS FAR NORTHEAST TENNESSEE AND SOUTHWEST VIRGINIA
FOR ADDITIONAL CONVECTIVE INITIATION. STRONG EFFECTIVE SHEAR AND
INCREASING DCAPES WILL SUPPORT AT LEAST A ISOLATED WIND DAMAGE
AND FLOODING THREAT WHERE STORMS TRAIN ALONG THE BOUNDARY.
DEPENDING ON HOW MUCH CLEARING TAKES PLACE AND RESULTING CAPE
PROFILES, CANNOT RULE OUT SOME SMALL HAIL AS WELL.
AN UPPER LOW IS EXPECTED TO BE CUTOFF AS WE HEAD INTO THE NEW WORK
WEEK, WHICH WILL CONTINUE TO PROMOTE DAILY CHANCES OF SHOWERS AND
STORMS AMONG SLIGHTLY BELOW NORMAL TEMPERATURES. SOME
DETERMINISTIC MODELS BEGIN TO EJECT THE LOW LATE WEEK, WITH A
DOWNWARD TREND IN PRECIP CHANCES AND SLIGHT WARMING TREND.
AVIATION
(18Z TAFS)
ISSUED AT 156 PM EDT SAT AUG 1 2026
RAIN SHIELD IS MOVING FROM THE CENTRAL TO EASTERN PORTIONS OF THE
FORECAST AREA AT THIS TIME. THE BACK EDGE SHOULD BE THROUGH TYS
WITHIN THE NEXT HOUR OR SO, AND ESTIMATED AROUND 20/21Z FOR TRI.
REDUCED VISIBILITY AND OCCASIONAL CIG REDUCTIONS CANNOT BE RULED
OUT WITH THIS ACTIVITY. UNSETTLED PATTERN CONTINUES AS ADDITIONAL
SHOWERS AND STORMS DEVELOP AND ADVECT WEST TO EAST THIS EVENING
INTO THE OVERNIGHT HOURS. THUNDERSTORM CHANCES ARE GREATEST AT
CHA/TYS. LINGERING MVFR CONDITIONS ARE POSSIBLE BEHIND THE
ACTIVITY OVERNIGHT. HOWEVER, THE LOWEST UNCERTAINTY IS AT TRI DUE
TO EXPECTED DOWNSLOPING. MOS AND LAMP GUIDANCE IS AGGRESSIVE WITH
LOW CIGS WHILE HREF PROBABILITIES ARE LESS THAN 20% AT TRI.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 72 86 70 85 / 90 30 20 70
KNOXVILLE MCGHEE TYSON AIRPORT, TN 72 86 70 84 / 80 40 40 80
OAK RIDGE, TN 71 84 69 84 / 90 40 40 80
TRI CITIES AIRPORT, TN 69 83 68 82 / 70 80 60 70
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
DISCUSSION...KRS
AVIATION...KRS
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