885
FXUS64 KMRX 181907
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
307 PM EDT SAT JUL 18 2026
..NEW DISCUSSION
KEY MESSAGES
UPDATED AT 246 PM EDT SAT JUL 18 2026
- DAILY CHANCES OF SHOWERS AND STORMS CONTINUE THROUGH THE
WEEKEND. A FEW STRONG TO MARGINALLY SEVERE STORMS COULD PRODUCE
GUSTY WINDS AND LOCALIZED FLOODING.
- MUGGY CONDITIONS WITH NEAR NORMAL TEMPERATURES CONTINUE THROUGH
THE EARLY NEXT WEEK.
- DRIER AND COOLER CONDITIONS EXPECTED FOR THE LATTER HALF OF NEXT
WEEK.
DISCUSSION
ISSUED AT 246 PM EDT SAT JUL 18 2026
THIS AFTERNOON AN UPPER LEVEL SHORTWAVE IS TRANSLATING SOUTH THROUGH
THE CANADIAN PROVINCE OF ONTARIO. THE ASSOCIATED AMPLIFICATION OF
TROUGHING ACROSS THE GREAT LAKES AND OHIO VALLEY WILL HELP FLATTEN
THE SOUTHEASTERN CONUS RIDGING. TRENDS OF THE 12Z HREF MEMBERS HAVE
BEEN TO KEEP THIS AFTERNOON AND EVENINGS CONVECTIVE COVERAGE MORE
ISOLATED TO SCATTERED. LATEST RADAR TRENDS SUGGEST THAT WE ARE
SOMEWHERE BETWEEN THE MOST BULLISH AND MOST PASSIVE MODELS, WITH
MORESO WEAKLY SCATTERED COVERAGE IN VICINITY OF CONFLUENCE AND
CONVERGENCE AT H85.
ADMITTEDLY, CONFIDENCE IS ON THE LOWER SIDE OF HOW EXACTLY THE
COVERAGE OF STORMS PLAYS OUT THIS AFTERNOON, LARGELY DUE TO POOR MID-
LEVEL LAPSE RATES THANKS TO AN UPPER LEVEL HIGH CENTERED OVER THE
CWA. SO FAR THIS HIGH HAS DONE A PRETTY DECENT JOB AT TAMING
CONVECTION TRYING TO SPROUT ACROSS THE VALLEY, WITH THE BEST
COVERAGE NEAR AREAS OF HIGHER TERRAIN. NONETHELESS, WITH 1500-2500
J/KG MLCAPE A FEW STRONG TO SEVERE STORMS CANNOT BE RULED OUT. WITH
PWATS IN THE 90TH PERCENTILE, SOME ISOLATED FLOODING WILL BE
POSSIBLE WHERE MULTIPLE STORMS TRACK OVER ONE LOCATION.
A MOSTLY QUIET OVERNIGHT IS EXPECTED AS A SURFACE COLD FRONT BEGINS
TO SINK INTO THE SOUTHERN OHIO VALLEY. HOWEVER, A FEW CAMS SUGGEST
SOME CONVECTION SURVIVING ALONG THE PREVIOUS EVENINGS OUTFLOW AND
SOME FOLKS, MAINLY NORTH OF I-40, COULD WAKE TO A FEW RUMBLES OF
THUNDER AND RAIN. ADDITIONAL SCATTERED SHOWERS AND STORMS ARE
EXPECTED TO DEVELOP AS THE DIFFUSE FRONT WORKS SOUTH INTO THE
AFTERNOON AND EVENING. SIMILAR STORY IN THAT YOU CANNOT RULE OUT A
FEW STRONG TO MARGINALLY SEVERE STORMS WITH LOCALIZED FLOODING DUE
TO THE ANOMALOUS MOISTURE AVAILABILITY.
BEST CHANCE FOR ADDITIONAL PRECIPITATION IN WAKE OF THE WASHING OUT
FRONT WILL BE IN THE HIGHER TERRAIN AND THE VERY SOUTHERN TIER OF
COUNTIES. LONG RANGE GUIDANCE IS STILL VERY BULLISH RELATIVE TO THE
NAM NOW COMING INTO RANGE, AND NBM PROBABILITIES MAY BE WEIGHTED TOO
HIGH BECAUSE OF THIS. THE NEXT FOCUS WILL BE THE POTENTIAL FOR A FEW
STRONG TO SEVERE STORMS IN THE TUESDAY NIGHT TO WEDNESDAY TIMEFRAME.
TIMING STILL REMAINS QUITE VARIABLE BETWEEN DETERMINISTIC MODELS,
BUT OVERALL, A MORE PROMINENT SHORTWAVE IS EXPECTED TO DIVE INTO
THE UPPER TROUGH AND AMPLIFY LOW AND MID-LEVEL FLOW. WITH
INCREASED SHEAR PROFILES AND A CONTINUED UNSTABLE AIRMASS THAT
STRONG TO SEVERE THREAT WILL PERSIST. AS IT STANDS, THE DAY 4/5
CONVECTIVE OUTLOOKS SIT ON THE CWA FRINGES. POST FRONTAL PASSAGE,
DRIER AND COOLER AIR MOVE INTO THE REGION FOR MID TO LATE WEEK.
AVIATION
(18Z TAFS)
ISSUED AT 149 PM EDT SAT JUL 18 2026
ANOTHER ROUND WITH ISOLATED TO SCATTERED AFTERNOON SHOWERS AND
STORMS. HOWEVER, CONFIDENCE IN DIRECT IMPACTS TO A TERMINAL ARE
LOWER RELATIVE TO YESTERDAY DUE TO THE PRESENCE OF AN UPPER LEVEL
HIGH CENTERED OVER EAST TN. TONIGHT, A COLD FRONT WILL MOVE INTO
NORTHERN KY. A FEW SHOWERS AND STORMS WILL BE POSSIBLE IN THE MID
TO LATE MORNING AT TRI AND MAYBE TYS ASSOCIATED WITH OUTFLOW.
INCLUDED A MENTION OF MVFR CIGS AT TRI WITH THIS ACTIVITY.
ADDITIONAL AFTERNOON CONVECTION TOMORROW AFTERNOON.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 73 91 73 91 / 10 60 20 50
KNOXVILLE MCGHEE TYSON AIRPORT, TN 73 88 72 89 / 40 70 20 50
OAK RIDGE, TN 72 88 72 89 / 30 80 30 50
TRI CITIES AIRPORT, TN 69 84 68 87 / 60 70 40 50
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
DISCUSSION...KRS
AVIATION...KRS
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