481
FXUS64 KMRX 201151
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
751 AM EDT WED MAY 20 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 749 AM EDT WED MAY 20 2026
- ABOVE NORMAL TEMPERATURES CONTINUE TODAY WITH HIGHS ROUGHLY 10
DEGREES ABOVE NORMAL.
- SCATTERED TO NUMEROUS SHOWERS AND STORMS EXPECTED TODAY AND INTO THE
WEEKEND. A FEW STRONG STORMS ARE POSSIBLE TODAY, AND PERHAPS
FRIDAY AS WELL.
DISCUSSION
ISSUED AT 151 AM EDT WED MAY 20 2026
COVERAGE OF SHOWERS AND STORMS WILL BE GREATER TODAY DUE TO AN
INCREASE IN FORCING THANKS TO A WEAK SHORTWAVE AND FRONTAL BOUNDARY
MOVING INTO THE AREA. HREF MEAN CAPE VALUES ARE AROUND 500 TO 800
J/KG FOR MOST OF THE AREA. SPC DAY 1 OUTLOOK HAS A MARGINAL RISK
IN PLACE FOR NORTHEAST TN AND OUR SOUTHWEST VA COUNTIES. THIS
APPEARS WARRANTED AS THERE WILL BE SOME LOW-END 0-6KM BULK SHEAR
ACROSS THESE AREAS; HREF MEANS GENERALLY YIELD AROUND 20 KTS. FOR
THIS REASON, A FEW STRONG TO SEVERE STORMS ARE POSSIBLE DURING THE
LATE AFTERNOON/EVENING HOURS. THE MAIN THREATS WILL BE SMALL HAIL
AND ISOLATED DAMAGING WIND GUSTS.
MODELS STILL SHOWING AN INCREASE IN PW VALUES, AROUND 1.6 TO 1.8
INCHES, ON THURSDAY. WIDESPREAD TO NUMEROUS SHOWERS AND STORMS ARE
EXPECTED AREAWIDE THROUGH THE DAY. DUE TO THE MOISTURE INCREASE,
SOME LOCALLY TO MODERATE TO HEAVY DOWNPOURS ARE EXPECTED. THE SEVERE
THREAT IS LOWER THAN WEDNESDAY THOUGH DUE TO AN ABSENCE OF SHEAR.
A WARM, MOIST SOUTHERLY FLOW WILL CONTINUE ON FRIDAY. IN ADDITION,
AN AREA OF LOW PRESSURE WILL BE MOVING NORTHEAST FROM THE LOWER
MISSISSIPPI RIVER VALLEY AND INTO MISSOURI. THIS WILL ALLOW FOR
SHOWERS AND STORMS ACROSS THE REGION. LREF MEANS SHOW LOW/MODERATE
INSTABILITY AND LOW-END 0-6KM BULK SHEAR ACROSS MUCH OF THE AREA. IF
THIS OCCURS, A FEW STRONG TO SEVERE STORMS WILL BE POSSIBLE
AREAWIDE.
SHOWER AND STORM CHANCES CONTINUE OVER THE WEEKEND AND INTO EARLY
NEXT WEEK AS WE REMAIN IN A SOUTHWEST FLOW PATTERN. WITH AN UPPER
TROUGH TO OUR NORTHWEST, AND HIGH PRESSURE TO OUR SOUTHEAST, SEVERAL
DISTURBANCES WILL MOVE THORUGH THE SOUTHWEST FLOW AND ACROSS OUR
REGION. THE ENVIRONMENT WILL CONTINUE TO BE MOIST AND UNSTABLE AND
WILL SUPPORT CONTINUED CHANCES FOR SHOWERS AND STORMS EACH DAY. THE
PRIMARY IMPACTS DURING THIS TIMEFRAME LIGHTNING AND LOCALLY HEAVY
RAINFALL.
QPF THROUGH THE NEXT 7 DAYS WILL WIDELY VARY ACROSS OUR AREA. SOME
AREAS WILL RECEIVE SEVERAL INCHES OF RAIN AND OTHER AREAS MUCH LESS.
AREAS THAT SEE REPEATED SHOWERS AND STORMS OVER NUMEROUS DAYS WILL
SEE THE MOST RAINFALL.
AVIATION
(12Z TAFS)
ISSUED AT 749 AM EDT WED MAY 20 2026
VFR TO CONTINUE UNTIL RAIN OR TS WORSENS CONDITIONS. CONVECTION
TODAY WILL BE SCATTERED MOSTLY, WITH MOUNTAINS AND PLATEAU FOCAL
AREAS, LESSER CONFIDENCE IN THE VALLEY. LATE IN THE PERIOD, LOW
CONFIDENCE IN CIG, WITH AT LEAST LOW (10 TO 20%) POTENTIAL FOR
MVFR CIGS, ALONG WITH RE-DEVELOPMENT OF LIGHT RAIN SHOWERS BY THE
END OF THE PERIOD. WINDS GENERALLY LIGHT OUTSIDE OF ANY TS.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 89 66 84 66 / 70 50 80 80
KNOXVILLE MCGHEE TYSON AIRPORT, TN 89 66 83 65 / 50 50 90 70
OAK RIDGE, TN 88 64 82 63 / 60 40 90 70
TRI CITIES AIRPORT, TN 88 63 81 62 / 30 60 80 60
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
DISCUSSION...99
AVIATION...WELLINGTON
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