041
FXUS64 KMRX 051842
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
242 PM EDT WED AUG 5 2026
..NEW DISCUSSION
KEY MESSAGES
UPDATED AT 241 PM EDT WED AUG 5 2026
- DAILY CHANCES OF SHOWERS AND STORMS WILL CONTINUE EACH DAY
THROUGH THE FORECAST PERIOD, PRIMARILY FAVORING THE AFTERNOON
AND EVENING HOURS. A LOW CHANCE FOR LOCALIZED FLOODING EXISTS
EACH DAY.
- LOW END CHANCE FOR ISOLATED FLOODING, WITH CONTINUOUS AFTERNOON
THUNDERSTORMS, HIGHEST CHANCES WILL BE ALONG THE PLATEAU AND
APPALACHIANS WHERE STORMS ARE MOST LIKELY EACH AFTERNOON.
DISCUSSION
ISSUED AT 241 PM EDT WED AUG 5 2026
THE SLOW MOVING UPPER LEVEL LOW CURRENTLY OVERHEAD WILL GRADUALLY
DISSIPATE AND BE ABSORBED INTO THE MEAN FLOW OVER THE NEXT COUPLE OF
DAYS. DURING THIS TRANSITION, STEADY AUGUST MOISTURE AND DAYTIME
HEATING WILL ALLOW SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
TO FIRE OFF EACH AFTERNOON. MESOANALYSIS AND FORECAST SOUNDINGS
INDICATE A RELATIVELY MOIST AIRMASS WITH DEWPOINTS IN THE UPPER 60S
TO LOW 70S HELPING TO INCREASE MLCAPE VALUES, GENERALLY RANGING FROM
1000 TO 2000 J/KG. GIVEN WEAK STEERING FLOW OF GENERALLY 10 KNOTS OR
LESS, SLOW MOVING STORMS WILL HAVE THE POTENTIAL TO DROP A QUICK
COUPLE OF INCHES OF RAIN OVER A SHORT PERIOD. 1-HOUR FLASH FLOOD
GUIDANCE RANGES FROM 1.5 TO 2 INCHES ACROSS THE FOOTHILLS AND EAST
TENNESSEE MOUNTAINS, AND 1.5 TO 2.5 INCHES IN SOUTHEAST TENNESSEE
AND SOUTHWEST NORTH CAROLINA. SLOW MOVING STORMS TRACKING OVER
ALREADY SATURATED SOILS OR ANCHORING TO TERRAIN FEATURES WILL
PRESENT AN ISOLATED FLASH FLOOD THREAT. ADDITIONALLY, DEEP PROFILES
AND HIGH FREEZING LEVELS WILL SUPPORT A MIX OF GUSTY WINDS, FREQUENT
LIGHTNING, AND BRIEF SMALL HAIL WITH THE STRONGER CORE STRUCTURES.
AS THE UPPER LOW FEATURE DAMPENS OUT TO END THE WEEK, OROGRAPHICALLY
FORCED CONVECTION WILL BECOME INCREASINGLY DOMINANT OVER BROADER
VALLEY BASED HEATING ELEMENTS, THOUGH ANY LINGERING OUTFLOW
BOUNDARIES COULD STILL SPARK SECONDARY VALLEY DEVELOPMENT. HIGH
TEMPERATURES WILL HOVER NEAR SEASONAL NORMALS, GENERALLY IN THE
MIDDLE TO UPPER 80S FOR LOWER ELEVATIONS.
HEADING INTO THE WEEKEND AND EARLY NEXT WEEK, THE REMNANTS OF THE
UPPER LOW PHASE COMPLETELY INTO THE MEAN FLOW ALOFT, WHILE A
NORTHERN STREAM TROUGH DROPS INTO THE GREAT LAKES REGION. THIS SETUP
WILL MAINTAIN WEAK UPPER LEVEL DIVERGENCE ACROSS THE SOUTHERN
APPALACHIANS. DIURNAL HEATING COMBINED WITH CONTINUOUS DEEP LAYER
MOISTURE WILL MAINTAIN DAILY CHANCES OF AFTERNOON/EVENING
CONVECTION. BY EARLY NEXT WEEK, DETERMINISTIC MODELS DIVERGE
REGARDING SYNOPTIC DETAILS AND LOW LEVEL JET ENHANCEMENTS WITH THE
GFS REMAINING MORE BULLISH ON COVERAGE COMPARED TO THE DRIER ECMWF.
NBM PAINTS A BROAD 40-50% POPS FOR MUCH OF THE AREA IN RESPONSE.
CIPS ANALOGS SUGGEST THAT ANY ENHANCED SEVERE WEATHER THREAT WILL
REMAIN DISPLACED TO OUR NORTH AND EAST CLOSER TO STRONGER SYNOPTIC
FORCING AND DEEP-LAYER SHEAR, LEAVING OUR AREA LOCKED INTO TYPICAL
LATE SUMMER DIURNAL PULSE ACTIVITY WITH HEAVY DOWNPOURS AS THE
PRIMARY HAZARD.
AVIATION
(18Z TAFS)
ISSUED AT 225 PM EDT WED AUG 5 2026
TODAY, VFR CONDITIONS ARE EXPECTED OUTSIDE OF NON-ZERO CHANCE FOR
THUNDERSTORMS THIS AFTERNOON. SCATTERED SHOWERS AND STORMS WILL
BE POSSIBLE NEAR ALL TERMINALS THIS AFTERNOON AND EARLY EVENING,
BUT CONFIDENCE IN DIRECT IMPACT TO EACH SITE IS LOW SO I HAVE
CONTINUED THE PROB30 GROUP W/TSRA. ANY SITE THAT DOES RECEIVE RAIN
WILL LIKELY SEE BR/FG DEVELOPMENT TONIGHT/EARLY THURSDAY MORNING
AS LIGHT WINDS TURN CALM AND SKIES CLEAR OUT OVERNIGHT. I HAVE
KEPT THE IFR VSBY AT KTRI GIVEN THE FAVORABLE ENVIRONMENT, BUT
LEFT IT OUT AT THE OTHER TWO SITES GIVEN LOW CONFIDENCE. WINDS
TURN LIGHT AND VARIABLE, PRIMARILY OUT OF THE SOUTH/SOUTHWEST
AROUND 5KTS THURSDAY MORNING.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 72 88 72 89 / 20 60 20 40
KNOXVILLE MCGHEE TYSON AIRPORT, TN 71 87 71 88 / 10 60 10 50
OAK RIDGE, TN 70 87 70 88 / 10 60 10 50
TRI CITIES AIRPORT, TN 67 85 67 85 / 10 50 30 50
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
DISCUSSION...99
AVIATION...BPH
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