934
FXUS64 KMRX 202332
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
732 PM EDT WED MAY 20 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 729 PM EDT WED MAY 20 2026
- RAIN CHANCES INCREASE THIS AFTERNOON AND EVENING, WITH CONTINUED
HIGH RAIN CHANCES THROUGH THE FIRST HALF OF NEXT WEEK.
- ORGANIZED SEVERE STORMS APPEAR UNLIKELY DURING THIS FORECAST
PERIOD, BUT THE PRIMARY THREATS WITH STORMS EACH DAY WILL BE
LIGHTNING, LOCALLY HEAVY RAINFALL, AND SOME GUSTY WINDS.
DISCUSSION
ISSUED AT 343 PM EDT WED MAY 20 2026
CONVECTION HAS GOTTEN OFF TO AN EARLY START TODAY IN AN
INCREASINGLY MOIST AIR MASS, DEVELOPING IN MIDDLE TN AND THE
PLATEAU, WHICH IS AN AREA OF HIGHER SURFACE CAPE VALUES AROUND
1500 J/KG AND SURFACE CONFLUENCE. THERE IS LITTLE TO NO SHEAR TO
HELP SUSTAIN OR ORGANIZE THESE STORMS, SO THEY WILL MAINLY BE
DRIVEN BY OUTFLOW BOUNDARIES, TERRAIN, AND CONVERGENCE ZONES.
EXPECT THAT COVERAGE WILL INCREASE IN THE CENTRAL AND SOUTHERN TN
VALLEY OVER THE NEXT FEW HOURS. THE MAIN HAZARDS WILL BE LIGHTNING
AND SOME LOCALLY HEAVY RAINFALL THAT COULD CAUSE MINOR FLOODING
ISSUES.
ISOLATED TO SCATTERED SHOWERS ARE EXPECTED TO PERSIST THROUGH THE
NIGHT DUE TO THE MOISTURE RICH ENVIRONMENT, THE PRESENCE OF A
MIDLEVEL SHORTWAVE TROUGH, AND SOME UPPER DIVERGENCE. A FRONT IN THE
OH VALLEY REGION TODAY WILL MOVE SOUTHWARD AND BE NEAR OUR NORTHWEST
BORDER BY THURSDAY MORNING. THIS WILL ACT AS A FOCUS FOR CONVERGENCE
AND CONVECTIVE DEVELOPMENT THURSDAY. POPS WILL BE CATEGORICAL ACROSS
THE ENTIRE AREA, WITH A CHANCE OF THUNDERSTORMS. INSTABILITY AND
SHEAR WILL BE LACKING FOR ANY ORGANIZED SEVERE THREAT, ALTHOUGH SOME
GUSTY DOWNBURSTS WINDS AND LOCALLY HEAVY RAINFALL WILL BE
POSSIBLE.
A STRENGTHENING SOUTHERLY FLOW AHEAD OF A LOW OVER AR LIFTS THE
AFOREMENTIONED BOUNDARY NORTHWARD ON FRIDAY, PUTTING OUR AREA INTO
THE WARM SECTOR IN THE AFTERNOON. LREF JOINT PROBABILITIES OF CAPE >
1000 J/KG AND SHEAR > 25 KT ARE AROUND 30% ACROSS THE AREA, AND NEAR
40% IN OUR SOUTHERN SECTIONS WHERE CLOUDS MAY SCATTER ENOUGH TO
ENHANCE AFTERNOON HEATING. A FEW STRONG TO SEVERE STORMS CANNOT BE
RULED OUT FOR FRIDAY, BUT THE CHANCE REMAINS LOW.
A DEEP SW FLOW PERSISTS THROUGH THE WEEKEND AND EARLY NEXT WEEK,
WITH BROAD TROUGHING OVER THE CENTRAL US. DISTURBANCES EJECTING FROM
THIS BROAD TROUGH WILL BRING SEVERAL ROUNDS OF ENHANCED RAIN CHANCES
THROUGH EARLY NEXT WEEK, BUT THE TIMING OF THESE DISTURBANCES
REMAINS HIGHLY UNCERTAIN. OVERALL, THE PATTERN FAVORS CONTINUED
HIGH RAIN CHANCES EACH DAY. THE PRIMARY IMPACTS WILL BE LIGHTNING
AND LOCALLY HEAVY RAINFALL. QPF THROUGH THE NEXT 7 DAYS WILL VARY
WIDELY ACROSS OUR AREA, DEPENDING ON WHICH AREAS SEE REPEATED
SHOWERS AND STORMS OVER NUMEROUS DAYS. GENERALLY SPEAKING, 1-3" OF
RAIN IS FORECAST THROUGH THE PERIOD.
AVIATION
(00Z TAFS)
ISSUED AT 729 PM EDT WED MAY 20 2026
MOSTLY VFR CONDITIONS THROUGH THE PERIOD, OUTSIDE OF ANY
THUNDERSTORMS THAT PASS OVER THE TERMINALS. ISOLATED TO SCATTERED
SHOWERS AND STORMS WILL PERSISTS THROUGH MOST OF THE PERIOD.
MVFR/IFR POSSIBLE WITH ANY STORM.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 66 83 65 83 / 70 60 90 90
KNOXVILLE MCGHEE TYSON AIRPORT, TN 66 81 64 82 / 70 90 50 90
OAK RIDGE, TN 64 81 63 81 / 70 80 60 90
TRI CITIES AIRPORT, TN 62 79 61 80 / 70 90 50 80
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
DISCUSSION...DGS
AVIATION...99
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page