980
FXUS64 KMRX 242326
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
726 PM EDT THU JUL 24 2025
..NEW AVIATION
SHORT TERM
(THIS EVENING THROUGH FRIDAY)
ISSUED AT 1245 PM EDT THU JUL 24 2025
KEY MESSAGES:
1. MOSTLY DRY THIS EVENING AND FRIDAY AFTERNOON. ISOLATED SHOWERS
AND STORMS WILL MAINLY BE ACROSS THE MOUNTAINS.
2. HOT AND HUMID CONDITIONS CONTINUE.
DISCUSSION:
UPPER-LEVEL RIDGE WILL CONTINUE TO PRODUCE SYNOPTIC CONDITIONS
UNFAVORABLE TO WIDESPREAD CONVECTION WITH POOR LAPSE RATES AND
LIMITED INSTABILITY, EVEN WITH THE HOT AND HUMID SURFACE
CONDITIONS. THIS RIDGING AND WARMER AIR ALOFT WILL RESULT IN VERY
WARM SURFACE TEMPERATURES IN THE LOW TO MID 90S TODAY AND TOMORROW
WITH HEAT INDEX VALUES APPROACHING 100F.
PATCHY FOG IS EXPECTED TONIGHT, ESPECIALLY FOR AREAS THAT RECEIVE
ANY RAINFALL THIS AFTERNOON. SOME FOG MAY BE DENSE, BUT IT SHOULD
BE LOCALIZED AND PATCHY IN NATURE.
LONG TERM
(FRIDAY NIGHT THROUGH NEXT THURSDAY)
ISSUED AT 1245 PM EDT THU JUL 24 2025
KEY MESSAGES:
1. RIDGING INCREASES THIS WEEKEND WITH LOW PROBABILITY DIURNAL
SHOWERS/THUNDERSTORMS.
2. HEAT AND HUMIDITY WILL PUSH HEAT INDEX VALUES INTO THE LOW 100S
OVER THE WEEKEND.
3. WEAK COLD FRONT AND WEAKNESS IN THE RIDGE MAY BRING INCREASING
SCATTERED CONVECTION TO THE REGION TOWARDS THE MIDDLE OF NEXT
WEEK.
DISCUSSION:
UPPER RIDGE WILL RETROGRADE ACROSS THE REGION THIS WEEKEND WITH
THE 597-598 DAM 500MB RIDGE CENTERED ACROSS THE TENNESSEE AND
LOWER MISSISSIPPI VALLEYS. SYNOPTIC SUBSIDENCE ALONG THE NORTHERN
AND EASTERN SIDE OF THE RIDGE, ALONG WITH WARM AIR ALOFT, WILL
LIMIT CONVECTIVE COVERAGE. ISOLATED CONVECTION WILL BE POSSIBLE
EACH AFTERNOON, MAINLY ACROSS THE HIGHER ELEVATIONS, BUT
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE NOT EXPECTED. THIS
ANOMALOUS RIDGING WILL BE NEAR THE MAX OF CLIMATOLOGY ACCORDING TO
NAEFS FORECAST PERCENTILES. WHILE IT WILL BE TOUGH TO REACH RECORD
HIGHS, WE WILL BE WITHIN A FEW DEGREES OVER THE WEEKEND.
DAILY RECORD HIGH MAXIMUM TEMPERATURES
DATE CHATTANOOGA KNOXVILLE TRI-CITIES OAK RIDGE
07-24 101(1952) 101(1934) 97(2016) 98(1993)
07-25 101(1952) 101(1934) 98(2016) 97(2016)
07-26 103(1993) 99(1993) 96(2016) 100(1993)
07-27 104(1952) 103(1952) 99(1952) 102(1952)
07-28 106(1952) 103(1952) 102(1952) 105(1952)
07-29 105(1952) 101(1952) 102(1952) 103(1952)
07-30 99(1999) 98(1995) 96(1995) 100(1995)
HEAT INDEX VALUES WILL BE APPROACHING 100F-105F ON SATURDAY AND
SUNDAY AFTERNOON, ESPECIALLY ACROSS THE SOUTHERN VALLEY BETWEEN
CHATTANOOGA AND KNOXVILLE.
THE UPPER RIDGE CONTINUES TO RETROGRADE WESTWARD WITH A WEAK FRONT
POTENTIALLY MOVING SOUTHEAST TOWARDS THE SOUTHERN APPALACHIANS ON
WEDNESDAY/THURSDAY OF NEXT WEEK. THERE'S SIGNIFICANT UNCERTAINTY
WITH HOW FAR SOUTH THIS FRONT WILL MOVE, AND EVEN IF IT DOES MAKE
IT THIS FAR SOUTH, CONVECTION MAY BE MORE SPOTTY AND LIMITED IN
COVERAGE TO LOCATIONS DIRECTLY ALONG THE PRIMARY LINE OF FRONTAL
FORCING.
THE MAIN CONCERN THROUGHOUT THE SHORT TERM AND EXTENDED IS THE
HEAT AND HUMIDITY WHICH WILL POSE A HEALTH RISK. THOSE SPENDING
TIME OR WORKING OUTDOORS ARE ENCOURAGED TO REMAIN HYDRATED, TAKE
FREQUENT BREAKS IN SHADE OR AIR CONDITIONING, AND PLAN TO WORK
DURING THE COOLER HOURS OF THE DAY IN THE MORNING AND LATE
EVENING. REMEMBER THAT HEAT INDEX VALUES ARE CALCULATED IN THE
SHADE, THEY DON'T ACCOUNT FOR DIRECT SUNLIGHT. URBAN, PAVED AREAS
ALSO RETAIN ADDITIONAL HEAT AND CAN OFTEN BE MUCH WARMER THAN
OFFICIAL TEMPERATURE MEASUREMENTS. HEAT RELATED ILLNESS AND DEATHS
ARE PREVENTABLE; TAKE PRECAUTIONS TO MITIGATE THE RISK TO YOU AND
YOUR LOVED ONES.
AVIATION
(00Z TAFS)
ISSUED AT 723 PM EDT THU JUL 24 2025
UPPER RIDGING ACROSS THE TENNESSEE VALLEY AND SOUTHERN
APPALACHIANS WILL LIMIT CONVECTION TO MAINLY THE TERRAIN FEATURES.
GROUND FOG AND SCATTERED 500 FEET CLOUDS POSSIBLE AT TRI AND TYS,
OTHERWISE, VFR CONDITIONS ANTICIPATED AT ALL TAF SITES.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 74 93 75 94 / 0 30 0 30
KNOXVILLE MCGHEE TYSON AIRPORT, TN 73 94 74 94 / 0 40 10 30
OAK RIDGE, TN 72 94 73 93 / 0 30 10 40
TRI CITIES AIRPORT, TN 68 92 71 91 / 0 20 10 40
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
SHORT TERM...DH
LONG TERM....JB
AVIATION...DH
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