140 
FXUS64 KMRX 040543
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
143 AM EDT Fri Sep 4 2026

...New DISCUSSION, AVIATION...

.KEY MESSAGES...
Updated at 134 AM EDT Fri Sep 4 2026
 
- Very hot conditions will continue again today with highs
  reaching well into the 90s and heat index values approaching or
  exceeding 100 for most places outside the higher elevations. 
  Take frequent breaks and drink plenty of water when outdoors.

- Temperatures will gradually moderate some through the weekend with 
  a return of isolated to scattered showers and storms. 

- A few storms this afternoon/evening mainly in the northeast and
  then including most of the remainder of the area Saturday may
  become strong to severe, with damaging wind gusts the primary
  threat.

&&

.DISCUSSION...
Issued at 134 AM EDT Fri Sep 4 2026

In the upper levels, a ridge is centered overhead extending through 
the Central U.S. The ridge will weaken overhead slightly by this 
evening and shift a bit west. Troughing over the Northeast will dip 
a bit southward into the Mid-Atlantic. This puts our counties in 
northeast Tennessee and southwest Virginia closer to the northwest 
flow action zone of storms riding the ridge. However, it looks like 
those more organized storm clusters will stay to the north over Ohio 
and West Virginia today and tonight. CAMs confirm that and also that 
showers and storms will be isolated in the Tennessee Valley today 
and more scattered in the higher elevations. Since the northeast 
counties are on the fringe of the northwest flow action zone, some 
strong storms cannot be ruled out late this evening. SPC has extreme 
Northeast Tennessee and Southwest Virginia in a marginal risk for 
the uncertainty. 

Another very hot day is expected today due to the ridge overhead. A 
Heat Advisory is in effect for this afternoon and evening throughout 
most of the Tennessee counties, the only exception is the far east 
Tennessee mountains and extreme northeast Tennessee counties. The 
Virginia and North Carolina counties are not included but even areas 
outside of the advisory will be unseasonably hot with heat indices 
in the 100-104 range in the lower elevations. Within the advisory 
heat indices will be in the 105 to 108 degree range.

On Saturday, the trough dips into the Ohio Valley as the ridge 
narrows to the west centered over the Great Plains. At the surface, 
a weak cold front will move through the region Saturday, bringing a 
better chance showers and storms especially in the northeast. With 
better synoptic lift in place on Saturday, there is also a higher 
chance for strong to severe storms especially in extreme northeast 
Tennessee and southwest Virginia (SPC Slight risk), closer to the 
trough. Most of the rest of the region is under a marginal risk for 
severe, the exception is Chattanooga and surrounding counties since 
coverage will likely be less that far south. With good instability 
but weak deep layer shear and high freezing levels, the primary 
threat will be damaging straight-line winds. Saturday will be 
slightly cooler, maybe even significantly cooler if storms form 
earlier in the day which seems like a possibility. The southern 
Tennessee Valley south of Knoxville still may need a Heat Advisory 
for Saturday afternoon since storm coverage will be more isolated 
that far south.

Slightly cooler temps expected by Sunday after frontal passage. 
Although, not so much near Chattanooga despite what appears to be a 
clean frontal passage. There will still be some showers and storms 
mainly in the easternmost counties Sunday and Monday as the region 
stays sandwiched between a ridge to the west and a trough to the 
east. Monday will have cooler temps (although still very warm), with 
Chattanooga likely the only place to break 90. 

By midweek, the ridge is likely to wander back into the Southeast. 
Perhaps, bringing more hot, dry conditions.

Daily Record High Maximum Temperatures

Date    Chattanooga    Knoxville      Tri-Cities     Oak Ridge             
09-04   102(1954)      101(1954)      99(1954)       100(1954)      
09-05   104(1925)      103(1954)      99(1954)       102(1954)      
09-06   103(1925)      101(1954)      100(1954)      102(1954)      
09-07   104(1925)      102(1925)      100(1954)      99(1954)       
09-08   100(1925)      96(1941)       92(2002)       95(1999)       
09-09   102(1925)      100(1925)      95(1954)       97(1954)

&&

.AVIATION...
(06Z TAFS)
Issued at 134 AM EDT Fri Sep 4 2026

High pressure centered over the Southern Appalachians this
morning, will support clear and calm through the rest of the
nighttime hours. Nearby lake fog could again be possible at TRI
just before sunrise. Once we mix out, winds will be light and
variable with mid and high clouds later this afternoon. Chances 
of showers and storms around, but a fairly low chance/low 
confidence of occurrence at the terminals themselves.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             99  76  98  74 /  10   0  30  10 
Knoxville McGhee Tyson Airport, TN  97  75  96  71 /  10   0  20  20 
Oak Ridge, TN                       98  74  96  71 /  10  10  30  10 
Tri Cities Airport, TN              95  70  91  67 /  10  10  50  40 

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...Heat Advisory until 8 PM EDT /7 PM CDT/ this evening for 
     Anderson-Bledsoe-Bradley-Campbell-Claiborne-Grainger-
     Hamblen-Hamilton-Hancock-Hawkins-Jefferson-Knox-Loudon-
     Marion-McMinn-Meigs-Morgan-North Sevier-Northwest Blount-
     Northwest Cocke-Northwest Greene-Northwest Monroe-Rhea-
     Roane-Scott TN-Sequatchie-Union-West Polk.

VA...NONE.
&&

$$

DISCUSSION...McD
AVIATION...KS


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