839
FXUS64 KMRX 080614
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
114 AM EST SAT NOV 8 2025
..NEW DISCUSSION, AVIATION
KEY MESSAGES
UPDATED AT 1254 AM EST SAT NOV 8 2025
- MOSTLY DRY TODAY AS A COLD FRONT MOVES SOUTHEAST OF US.
- A STRONGER COLD FRONT WILL MOVE THROUGH SUNDAY, USHERING IN MUCH
COLDER WEATHER BY SUNDAY NIGHT. MAX TEMPERATURES ON MONDAY WILL
BE ABOUT 20 DEGREES BELOW NORMAL.
- THIS FRONT WILL ALSO BRING CHANCES FOR LIGHT SNOW TO THE REGION.
LIGHT ACCUMULATIONS ARE EXPECTED IN THE MOUNTAINS SUNDAY NIGHT
INTO MONDAY MORNING. WHILE A DUSTING IN THE VALLEY ISN'T OUT OF
THE QUESTION, NON-ACCUMULATING SNOWFALL LOOKS MORE LIKELY IN
THE LOWER ELEVATION AREAS.
DISCUSSION
ISSUED AT 1254 AM EST SAT NOV 8 2025
BROAD TROUGHING ACROSS THE EASTERN CONUS WILL RAPIDLY DEEPEN
TONIGHT THROUGH MONDAY NIGHT AS A VERY STRONG SYSTEM DROPS SOUTH
OUT OF CANADA. THE INITIAL WAVE THAT WILL KICK THIS OFF WILL MOVE
OUT OF THE NORTHERN ROCKIES, ACROSS THE PLAINS AND INTO THE
MIDWEST TODAY/TONIGHT WITH CYCLOGENESIS TAKING PLACE OVER MISSOURI
THIS AFTERNOON AND EVENING BENEATH THE DEVELOPING H3 JET STREAK.
SHOWERS LINGERING THIS MORNING WILL BE EAST OF THE AREA AS A COLD
FRONT MOVES SOUTHEAST OF US. THIS WILL LEAVE US DRY THROUGH MUCH
OF THE DAY, BUT THIS FRONT GETS PULLED BACK TO THE NORTH AS A WARM
FRONT TONIGHT AS THE SURFACE LOW DEVELOPS OVER MISSOURI AND MOVES
NORTHEASTWARD, FOLLOWED ANOTHER STRONG COLD FRONT PASSAGE ON SUN
MORNING. THIS LEADS US TO THE MOST IMPORTANT PART OF THE FORECAST,
THE CHANCES FOR ACCUMULATING SNOWFALL SUN AFTERNOON THROUGH MON.
BEHIND THE INITIAL WAVE TONIGHT INTO SUNDAY, AN EVEN STRONGER SYSTEM
DROPS SOUTH OUT OF CANADA AND MOVES FROM THE UPPER MIDWEST TOWARDS
THE TENNESSEE VALLEY SUN EVENING INTO MON. NAEFS TABLES PAINT A VERY
ANOMALOUS EVENT HERE, WITH BOTH H5 AND H85 HEIGHTS AND TEMPERATURES
NEARING THE LOWEST OBSERVED VALUES FOR THIS TIME OF YEAR. INDEED,
LOOKING AT SPC'S SOUNDING CLIMATOLOGY PAGE, THE LOWEST OBSERVED
NOVEMBER H5 HEIGHTS AT THE NASHVILLE SOUNDING LOCATION IS 530 DAM,
AND THE EUROPEAN MODEL SHOWS A 528 DAM H5 LOW SWINGING DIRECTLY
THROUGH OUR CWA ON MON. LOOKING AT NAEFS RETURN INTERVALS SHOWS A
SIMILAR PICTURE HERE, SHOWING INTERVALS OF 30 YEARS OR MORE FOR SOME
OF THESE SAME VALUES. ALL OF THIS IS TO SAY THAT BEHIND THE FRONT ON
SUN, TEMPERATURES WILL BE COOLING RAPIDLY AND THE NORTHWEST FLOW
REGIME IN ITS WAKE WILL DEFINITELY PROMOTE ACCUMULATING SNOWFALL IN
THE HIGHER TERRAIN AND EVEN SNOW DOWN TO THE VALLEY FLOOR, ALTHOUGH
IT'S HARD TO SAY WHAT THE LIKELIHOOD IS OF ACCUMULATING SNOW IN THE
LOW ELEVATIONS. FORECAST SOUNDINGS SHOW LOW LEVEL SATURATION
EXTENDING INTO THE DGZ SUN NIGHT INTO MON MORNING DUE TO THE COLD
TEMPERATURES IN PLACE, DESPITE THE SATURATED LAYER BEING EXPECTEDLY
SHALLOW IN THE NW FLOW REGIME. THE LREF PROBABILITIES OF GREATER
THAN 3" OF SNOW ARE FAIRLY LOW, SHOWING SOME 30-40 PERCENT ODDS IN
THE SMOKIES AND HIGHER TERRAIN NEAR SAMS GAP ALONG I-26. THE NBM
SHOWS SIGNIFICANTLY HIGHER ODDS THOUGH, WITH UPWARDS OF 60 PERCENT
IN THOSE SAME AREAS AND EVEN A 30-40 PERCENT CONTOUR UP AROUND THE
WISE COUNTY AREA. ON THE LOWER END, BOTH THE LREF AND AND NBM
GUIDANCE SHOW AT LEAST 30-40 PERCENT ODDS OF MEASURABLE SNOW (AT
LEAST A TENTH OF AN INCH) SUNDAY NIGHT INTO MONDAY MORNING FOR
THE LOWER ELEVATION AREAS NORTH OF THE KNOXVILLE METRO AREA IN THE
TN VALLEY. THE FORECAST REFLECTS THE HIGHER NBM TOTALS AS MODEL
GUIDANCE SHOWS THE GREATEST QPF BETWEEN 06Z-12Z MONDAY WHICH
FAVORABLY ALIGNS WITH THE COLDER OVERNIGHT TEMPS. DURING THE DAY
MONDAY, THE UPPER LOW SWINGS THROUGH AND EVEN THOUGH TEMPERATURES
MAY BE TOO WARM IN THE LOWER ELEVATIONS FOR ACCUMULATING SNOW, I
WOULD EXPECT THERE TO BE WIDESPREAD FLURRIES AND EVEN SOME
CONVECTIVE SNOW SHOWERS GIVEN THE LAPSE RATES IN PLACE. THE UPPER
LOW/TROUGH MOVES EAST OF US MONDAY NIGHT, WHICH SHOULD BRING AN
END TO PRECIP BY DAYBREAK TUE MORNING.
TEMPERATURES MONDAY WILL BE WELL BELOW NORMAL, WITH HIGHS ONLY IN
THE UPPER 30S IN THE SOUTH AND JUST ABOVE FREEZING IN THE NORTH.
LOWS IN THE 20S ARE EXPECTED MONDAY NIGHT. THE REMAINDER OF THE WEEK
LOOKS DRY, WITH TEMPERATURES REBOUNDING QUICKLY BY MIDWEEK AS
SOUTHERLY FLOW RETURNS, BOUNCING BACK INTO THE 40S ON TUE AND THE
50S TO LOW 60S BY WED AFTERNOON.
AVIATION
(06Z TAFS)
ISSUED AT 1254 AM EST SAT NOV 8 2025
THE LINE OF SHOWERS AND THUNDERSTORMS CONTINUES TO EXIT THE
FORECAST AREA. IN THE NEXT HOUR OR SO, TERMINALS SHOULD BE FREE
FROM ANY PRECIPITATION AND/OR LIGHTNING. THE REST OF THE MORNING,
LOW CIG AND FG POTENTIAL WILL NEED MONITORED. NEW TAF LINES OR
TEMPOS ADDED TO REFLECT THIS. BY MID-MORNING TAF SITES SHOULD
IMPROVE TO VFR WITH LIGHT WINDS. TONIGHT, A LOW PASSING EAST OF
THE MOUNTAINS, MAY PROVIDE A LOW END CHANCE OF SHOWERS. THIS IS
REFLECTED WITHIN THE LAST 6 HOURS OF THIS TAF ISSUANCE AT CHA AND
TYS.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 73 52 54 29 / 0 20 10 10
KNOXVILLE MCGHEE TYSON AIRPORT, TN 69 51 54 29 / 0 30 20 60
OAK RIDGE, TN 68 49 51 28 / 0 30 30 70
TRI CITIES AIRPORT, TN 65 46 53 28 / 0 20 40 80
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
DISCUSSION...CD
AVIATION...KS
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