894
FXUS64 KMRX 181104
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
704 AM EDT MON MAY 18 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 703 AM EDT MON MAY 18 2026
- VERY WARM TEMPERATURES ARE EXPECTED EARLY THIS WEEK WITH HIGHS 10
TO 15 DEGREES ABOVE NORMAL.
- INCREASING CHANCES FOR SHOWERS AND STORMS RETURN WEDNESDAY.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED EACH DAY FROM
THURSDAY THROUGH THE WEEKEND ESPECIALLY ACROSS THE HIGHER
ELEVATIONS.
DISCUSSION
ISSUED AT 128 AM EDT MON MAY 18 2026
MAIN WEATHER FEATURE FOR MONDAY AND TUESDAY WILL REMAIN AN UPPER
RIDGE OVER THE SOUTHEAST UNITED STATES INTO THE SOUTHERN
APPALACHIANS. MAIN IMPACT WILL BE MOSTLY DRY AND UNSEASONABLY VERY
WARM TEMPERATURES. HIGHS WILL BE 10 TO 15 DEGREES ABOVE NORMAL.
FOR WEDNESDAY, ENSEMBLE CLUSTER ANALYSIS SHOWS A SHORT-WAVE TROUGH
MOVING ACROSS THE GREAT LAKES AND UPPER OHIO VALLEY. THIS WAVE WILL
BEGIN TO WEAKEN THE UPPER RIDGE OVER THE REGION AND ALLOW A FRONTAL
BOUNDARY TO APPROACH THE AREA. SURFACE RIDGING WILL ALSO WEAKEN
ACROSS THE SOUTHEAST UNITED STATES ALLOWING FOR SLIGHTLY BETTER
MOISTURE RETURN. LOWER HEIGHTS AND BETTER PWS WILL ALLOW FOR
INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS ESPECIALLY OVER THE
PLATEAU COUNTIES. INSTABILITY WITH REMAIN MARGINAL WITH CAPES OF
1000-1500, MID-LEVEL LAPSE RATES OF 6 DEGREES OR LESS WITH LITTLE TO
NO SHEAR. AT THIS TIME SEVERE STORMS ARE NOT ANTICIPATED.
FOR THURSDAY, FRONTAL BOUNDARY REMAINS NEAR THE REGION WITH PWS OF
1.5-1.7 INCHES SO MOISTURE RETURNS OVER THE AREA. INSTABILITY AND
SHEAR REMAIN LIMITED WITH LITTLE TO NO SEVERE THREAT, BUT FAIRLY
GOOD COVERAGE OF SHOWERS AND STORMS WITH MUCH NEEDED RAINFALL.
QPF FOR WEDNESDAY THROUGH THURSDAY WILL RANGE FROM 0.10 TO 0.50 INCH.
FOR FRIDAY, FRONTAL BOUNDARY LIFTS NORTH AS AN UPPER TROUGH/JET
MOVES NORTHEAST INTO THE MID-WEST AND OHIO VALLEY PRODUCING PRESSURE
FALLS THERE. THE INCREASE IN SOUTHERLY BOUNDARY JET WILL PULL
FRONTAL BOUNDARY NORTH. PLENTY OF MOISTURE AND INSTABILITY REMAINS
SO SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING INTO THE AFTERNOON
ESPECIALLY ACROSS THE TERRAIN FEATURES.
FOR SATURDAY AND SUNDAY, THE SOUTHERN APPALACHIANS WILL REMAIN WITH
PLENTY OF MOISTURE AND AFTERNOON INSTABILITY WITH UPPER RIDGE
BUILDING BACK INTO THE REGION. MORE TYPICAL WARM AND MUGGY
CONDITIONS ARE EXPECTED.
ENSEMBLE QPF AND WPC DEPICTS FROM 1 TO 1.5 INCHES ACROSS MUCH OF THE
AREA FROM WEDNESDAY THROUGH THE WEEKEND.
AVIATION
(12Z TAFS)
ISSUED AT 703 AM EDT MON MAY 18 2026
VFR AND DRY WEATHER EXPECTED THE NEXT 24 HOURS. A FEW WIND GUSTS
TODAY TO 15 KNOTS, MAYBE 20 KNOTS AT TYS, THEN WINDS WILL LIGHTEN
ONCE MORE WITH SUNSET.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 89 67 89 66 / 20 0 10 10
KNOXVILLE MCGHEE TYSON AIRPORT, TN 90 66 90 67 / 10 0 0 10
OAK RIDGE, TN 89 65 88 64 / 10 0 0 10
TRI CITIES AIRPORT, TN 90 62 88 63 / 10 0 0 0
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
DISCUSSION...DH
AVIATION...WELLINGTON
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