821
FXUS64 KMRX 171846
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
246 PM EDT FRI JUL 17 2026
..NEW DISCUSSION
KEY MESSAGES
UPDATED AT 234 PM EDT FRI JUL 17 2026
- DAILY CHANCES OF SHOWERS AND STORMS CONTINUE THIS AFTERNOON
THROUGH THE WEEKEND. A FEW STRONG TO MARGINALLY SEVERE STORMS
COULD PRODUCE GUSTY WINDS AND LOCALIZED FLOODING.
- MUGGY CONDITIONS WITH NEAR NORMAL TEMPERATURES CONTINUE.
DISCUSSION
ISSUED AT 234 PM EDT FRI JUL 17 2026
AMIDST A SURFACE HIGH PRESSURE CENTER SLOWLY MEANDERING FROM THE
EASTERN GREAT LAKES REGION TOWARDS THE MID-ATLANTIC, BROAD RIDGING
IS IN PLACE FOR MUCH OF THE CONUS WITH TROUGHING OVER THE NORTHERN
CORNERS. A WEAK SOUTHERN STREAM DISTURBANCE WILL WORK WITH STRONG
DIURNAL HEATING TO PROMOTE SCATTERED CONVECTION CONTINUING THROUGH
THE AFTERNOON AND EVENING HOURS. MODEL DERIVED SOUNDINGS FROM LATEST
CAMS DEPICT 2000-3000 J/KG MLCAPE WITH VERY WEAK STEERING FLOW AND
PWAT VALUES INTO THE 90TH PERCENTILE. BECAUSE OF THIS, CANNOT RULE
OUT A FEW STRONG TO SEVERE DOWNBURSTS OR LOCALIZED FLOODING WHERE ANY
CELLS ANCHOR ONTO TERRAIN OR OUTFLOWS OF NEIGHBORING CONVECTION.
A SHORTWAVE WILL TRANSLATE THROUGH MEAN FLOW ALOFT, INCREASING
TROUGHING INFLUENCE IN THE OHIO VALLEY AND CENTRAL TO SOUTHERN
APPALACHIANS SATURDAY INTO SUNDAY. STEERING FLOW WILL BE IMPROVED SO
THE ISOLATED FLOODING THREAT WILL BE LESS RELATIVE TO THE PREVIOUS
DAY, BUT A WEAK SHEAR PROFILE MAY AID IN DEVELOPMENT OF SEMI-
ORGANIZED CLUSTERS THAT COULD LEAD TO A FEW STRONG TO SEVERE WIND
GUSTS ONCE AGAIN. HOWEVER, NAMBUFR SOUNDINGS DO LIMIT MLCAPE TO SUB
2K J/KG WITH INCREASED CLOUD COVERAGE SO CONFIDENCE IN THE
PROBABILITY FOR A FEW STRONG TO DAMAGING WIND GUSTS IS A LITTLE
LOWER. ADDITIONALLY, CANNOT RULE OUT SOME LINGERING SHOWERS AND
STORMS INTO THE OVERNIGHT PERIOD, MAINLY IN VICINITY OF SW VA.
AS THE MAIN VORT MAX WORKS THROUGH THE REGION SUNDAY, ADDITIONAL
SCATTERED CONVECTION IS ANTICIPATED WITH A DIFFUSE SURFACE FRONT
DRAPING INTO SOUTHERN KY. MLCAPE BETWEEN 1000-2000 J/KG AND
EFFECTIVE SHEAR NEAR 25KTS WILL CONTINUE TO PROMOTE A MARGINAL RISK
FOR A FEW STRONG TO SEVERE STORMS. HIGH PRESSURE ATTEMPTS TO BUILD
IN MONDAY, WITH POP CHANCES RESTRICTED TO THE MOUNTAINS. AN
ADDITIONAL WAVE WILL ROUND THE BASE OF THE TROUGH IN THE TUESDAY TO
WEDNESDAY TIME FRAME. WORTH KEEPING AN EYE ON THIS SYSTEM FOR
ADDITIONAL STRONG TO SEVERE CHANCES AS ANOMALOUS LOW-LEVEL FLOW MAY
ENHANCE EFFECTIVE SHEAR. BEHIND THIS SYSTEM WILL BE A COOLER AND
DRIER AIRMASS.
AVIATION
(18Z TAFS)
ISSUED AT 129 PM EDT FRI JUL 17 2026
SCATTERED SHOWERS AND STORMS WILL BE MOST PREVALENT AROUND TYS AND
CHA THIS AFTERNOON AND EVENING. THEY WILL HAVE THE ABILITY TO
PRODUCE BRIEF GUSTY WINDS, FREQUENT LIGHTNING, AND REDUCED
VISIBILITY DROPS IF ANY CONVECTION IMPACTS A TERMINAL DIRECTLY.
OTHERWISE PREDOMINANT VFR CONDITIONS ARE LARGELY EXPECTED. THERE
IS POTENTIAL FOR SOME FOG OR LOW CLOUD DEVELOPMENT AT TRI TOMORROW
MORNING. HOWEVER, HREF PROBABILITIES ARE GENERALLY 40% OR LESS SO
HAVE NOT INCLUDED A MENTION AT THIS TIME, THOUGH, INTRODUCTIONS
MAY NEED TO BE CONSIDERED WITH FUTURE TAF ISSUANCES.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 73 91 74 91 / 20 30 10 60
KNOXVILLE MCGHEE TYSON AIRPORT, TN 74 88 73 88 / 30 60 50 70
OAK RIDGE, TN 73 89 72 89 / 30 60 40 70
TRI CITIES AIRPORT, TN 72 87 70 85 / 30 70 70 80
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
DISCUSSION...KRS
AVIATION...KRS
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