924
FXUS64 KMRX 300438
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
1238 AM EDT MON JUN 30 2025
..NEW SHORT TERM, LONG TERM, AVIATION
SHORT TERM
(TODAY AND TONIGHT)
ISSUED AT 1200 AM EDT MON JUN 30 2025
KEY MESSAGES:
1. ISOLATED TO SCATTERED THUNDERSTORMS AGAIN THIS AFTERNOON. MANY
AREAS REMAIN DRY, BUT WHERE RAIN DOES FALL, HEAVY RAIN RATES ARE
EXPECTED.
2. CHANCES FOR OVERNIGHT CONVECTION BEGIN TO INCREASE TONIGHT AS
A SHORTWAVE TROUGH AND ASSOCIATED SURFACE FRONT APPROACH THE
REGION.
DISCUSSION:
OUR REGION WILL BE BETWEEN THE INFLUENCE OF A STRONG UPPER-LEVEL
RIDGE ACROSS THE WESTERN NORTH ATLANTIC AND AN AMPLIFYING UPPER-
LEVEL TROUGH ACROSS THE NORTHERN GREAT PLAINS AND MISSISSIPPI
VALLEY. WITH HIGHER SURFACE MOISTURE AND SLIGHTLY LOWER HEIGHTS
ACROSS OUR WESTERN COUNTIES, HIGHER INSTABILITY IS EXPECTED FOR
THESE AREAS WITH DECREASING INSTABILITY TO THE EAST. REFS AND HREF
GUIDANCE SHOWS MLCAPE VALUES NEAR 1500-2000 J/KG IN THE VICINITY
OF CHA, 1000-1500 J/KG IN THE VICINITY OF KNOXVILLE, AND NEAR 1000
J/KG NEAR THE TRI-CITIES REGION. FOR THIS REASON, HIGHEST
THUNDERSTORM CHANCES WILL BE ACROSS THE HIGHER ELEVATIONS OF THE
MOUNTAINS AND PLATEAU. HIGHEST PRECIPITATION COVERAGE WILL LIKELY
BE WEST OF INTERSTATE 75 THIS AFTERNOON WITH MORE ISOLATED
COVERAGE AROUND KNOXVILLE AND EASTWARD ACROSS THE VALLEY. ANY
THUNDERSTORMS THAT DEVELOP WITH PRODUCE ISOLATED DAMAGING WINDS
AND HEAVY RAIN RATES CAPABLE OF FLASH FLOODING WITH PW VALUES
AROUND 2.0 INCHES.
AS TROUGHING AMPLIFIES ACROSS THE MISSISSIPPI AND OHIO VALLEYS
TONIGHT, HEIGHT FALLS WILL INCREASE THE PROBABILITIES OF SCATTERED
SHOWERS OVERNIGHT AND INTO TUESDAY MORNING. SEVERE WEATHER IS NOT
EXPECTED, BUT ANY THUNDERSTORMS WILL LIKELY PRODUCE HEAVY RAIN
RATES AND LOCALIZED FLOODING.
LONG TERM
(TUESDAY THROUGH MONDAY)
ISSUED AT 1200 AM EDT MON JUN 30 2025
KEY MESSAGES:
1. FRONTAL BOUNDARY BRINGS WIDESPREAD SHOWERS AND THUNDERSTORMS
ON TUESDAY. HEAVY RAIN RATES EXPECTED.
2. DRIER WEATHER WEDNESDAY WITH LOW PRECIPITATION CHANCES ACROSS
SOUTHEAST TENNESSEE AND SOUTHWEST NORTH CAROLINA NEAR THE FRONT TO
OUR SOUTH.
3. RIDGING BRINGS HEAT AND DRY WEATHER LATE WEEK INTO THE WEEKEND.
HEAT INDEX VALUES WILL BE AROUND 100F ON FRIDAY THROUGH THE
WEEKEND.
DISCUSSION:
FRONTAL BOUNDARY WILL MOVE ACROSS THE REGION ON TUESDAY WITH
WIDESPREAD SHOWERS AND THUNDERSTORMS, MAINLY DURING THE AFTERNOON.
MOST AREAS ARE EXPECTED TO RECEIVE RAINFALL ON TUESDAY. MLCAPE
BETWEEN 1000-2000 J/KG WILL RESULT IN SOME STRONGER THUNDERSTORMS,
BUT THE CHANCE OF SEVERE WEATHER IS VERY LOW. HEAVY RAIN RATES
THAT MAY PRODUCE FLASH FLOODING WILL BE THE PRIMARY HAZARD ON
TUESDAY. WITH PW VALUES AROUND 2.0 TO 2.2 INCHES, RAIN RATES IN
EXCESS OF THREE INCHES PER HOUR ARE EXPECTED. THESE HEAVY RAIN
RATES CAN QUICKLY OVERWHELM URBAN AND DEVELOPED AREAS WITH HIGHER
PERCENTAGES OF IMPERVIOUS SURFACES.
BEHIND THE FRONT, DRIER WEATHER IS EXPECTED ON WEDNESDAY. LOW
PRECIPITATION CHANCES REMAIN ACROSS SOUTHEAST TENNESSEE AND
SOUTHWEST NORTH CAROLINA DURING THE DAY NEAR THE FRONT. SUBSIDENCE
AND DRIER AIR SHOULD KEEP THE REGION DRY ON THURSDAY AND FRIDAY.
WITH RIDGING IN PLACE, TEMPERATURES REMAIN WARM LATE WEEK AND INTO
THE WEEKEND. INCREASING MOISTURE WILL ALSO RESULT IN INCREASING
HEAT INDEX VALUES ON FRIDAY THROUGH THE WEEKEND. HEAT INDICES
NEAR 100 TO 105 DEGF ARE POSSIBLE BETWEEN CHATTANOOGA AND
KNOXVILLE ON FRIDAY (INDEPENDENCE DAY) THROUGH THE WEEKEND. IT
WILL BE IMPORTANT FOR PEOPLE TO PRACTICE HEAT SAFETY AND REMAIN
HYDRATED THIS HOLIDAY WEEKEND.
ISOLATED DIURNAL CONVECTION WILL START TO RE-ENTER THE FORECAST
ON SATURDAY, AND MORESO ON SUNDAY, MAINLY ACROSS THE HIGHER
ELEVATIONS OF THE MOUNTAINS.
AVIATION
(06Z TAFS)
ISSUED AT 1200 AM EDT MON JUN 30 2025
PREVAILING VFR CONDITIONS ARE EXPECTED WITH VCFG NEAR TERMINALS
THIS MORNING. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED
DURING THE AFTERNOON HOURS WITH THE GREATEST PROBABILITY FOR
THUNDERSTORM IMPACTS AT CHA. WINDS REMAIN LIGHT AND FROM THE
SOUTHWEST.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 91 72 88 71 / 60 40 90 20
KNOXVILLE MCGHEE TYSON AIRPORT, TN 90 71 86 69 / 60 50 100 30
OAK RIDGE, TN 89 71 85 68 / 60 50 100 20
TRI CITIES AIRPORT, TN 88 69 82 67 / 70 60 100 50
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...NONE.
VA...NONE.
SHORT TERM...JB
LONG TERM....JB
AVIATION...JB
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