845 
FXUS64 KMRX 211831
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
231 PM EDT Tue Apr 21 2026

...New DISCUSSION...

.KEY MESSAGES...
Updated at 230 PM EDT Tue Apr 21 2026

- Unseasonably warm and dry conditions will continue through
  Friday. Highs will be around 10 degrees above normal. Low 
  afternoon relative humidity each day with 20s and 30s expected.

- Increasing moisture and instability this weekend with likely 
  chances of showers and possibly storms, especially Saturday.

- Another round of storms anticipated for Monday and Tuesday. There 
  is a threat for strong to severe storms.  

&&

.DISCUSSION...
Issued at 230 PM EDT Tue Apr 21 2026

For Tonight and Wednesday, a short-wave will move across the upper 
Ohio valley into the central Appalachians. This wave will produce an 
area of showers and thunderstorms that will approach southwest 
Virginia toward Wednesday morning. At this time, the dynamics and 
moisture will stay north of the region with surface ridging, so dry 
conditions are anticipated. Low afternoon relative humidity will 
with values in the 20s. 

For Thursday and Friday, upper ridge builds over the area producing 
mostly dry and unseasonably warm conditions. Highs will be around 10 
degrees above normal. Low afternoon relative humidity will continue 
with values in the 20s/30s. 

For Friday night through Saturday, a northern stream (Great 
Lakes/Ohio Valley) and southern stream waves (central Gulf coast 
states) produce an area of showers and possibly a thunderstorm. 
Since limited phasing is expected with these waves, and instability 
and dynamics are limited, confidence is low on QPF amounts. 
Currently expecting from 0.25 to 0.50 inch but ensemble 
probabilities suggest lesser amounts.

Another system moves into the Tennessee valley and southern 
Appalachians early next week. The short-wave and jet dynamics will 
this wave is stronger and taps into Gulf moisture. Joint ensemble 
probability of CAPE/SHEAR suggest a great threat of strong to severe 
storms possible. Will need to watch the evolution of this system 
close as we move into the weekend for possible messaging of severe 
storms. CIPS Analog also suggest the potential of severe storms.

&&

.AVIATION...
(18Z TAFS)
Issued at 141 PM EDT Tue Apr 21 2026

VFR conditions will prevail through the next 24 hours at all TAF
sites. Increasing low level jet overnight with 850mb winds of
30-35 knots will produce a chance of LLWS at TRI but confidence is
not high enough to include. Westerly winds will increase at TRI
tomorrow morning to 12-14 knots and gusty.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             53  83  54  84 /   0   0   0   0 
Knoxville McGhee Tyson Airport, TN  51  81  54  82 /   0   0   0  10 
Oak Ridge, TN                       50  82  52  83 /   0   0   0  10 
Tri Cities Airport, TN              44  78  49  79 /   0   0   0  10 

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&

$$

DISCUSSION...DH
AVIATION...DH


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