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000
FXUS64 KMRX 160217
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
1017 PM EDT Mon Apr 15 2024

...New UPDATE...

.UPDATE...
Issued at 959 PM EDT Mon Apr 15 2024

Recent HRRR soundings suggest a low level inversion has developed
following the setting sun. This is further backed up by SPC
Mesoanalysis which shows that weak convective inhibition has
developed across much of the area. Additionally, surface
observations suggest that the better convergence along a weak
boundary remains displaced more so towards northern Kentucky.
This has resulted in the severe threat for southwest Virginia and
extreme northeast Tennessee trending downward and the most recent
convective outlook has been limited to a marginal risk. Given
DCAPE ranging from 700 to 1000J/kg and steep lapse rates, if an
isolated storm does drift into the region some gusty winds and
small hail will be possible. Otherwise, a fairly quiet night with
bands of mid to high level clouds streaming ahead. Temperatures
will sit comfortably in the upper 50s to low 60s for the morning
commute.

&&

.SHORT TERM...
(This evening through Tuesday)
Issued at 310 PM EDT Mon Apr 15 2024

Key Messages:

1.Chance of showers and thunderstorms in northern sections this
evening, with a few storms capable of producing large hail and
damaging winds. Storms possible in NE sections again Tuesday
afternoon.

2. Above normal temperatures continue for Tuesday, with highs in the
80s in most spots.

Discussion:

Convection has begun to develop along a pre-frontal trough across
northern WV/VA. In the next few hours, the CAMS show additional
development farther west, across southern OH/northern KY. This
expected activity will propagate SE, and could reach our SW VA
counties in the 00-06Z time frame. Right now, that area is capped,
but RAP mesoanalysis shows weakening CIN in the next few hours.
Given the steep midlevel lapse rates leading to MLCAPE near
2000J/kg, low WBZ heights, and adequate shear, large hail may be a
threat with the storms, along with damaging wind gusts. CAMS have
some discrepancies about when this activity will dissipate, but
expect a downward trend from 04-08Z as the boundary layer
stabilizes.

A 850-700 mb ridge axis crosses the area in the morning, with a weak
shortwave trough following behind it in the afternoon. With
afternoon heating and MLCAPE developing to near 1500 J/kg in NE
TN/SW VA, some strong to severe storms will be possible again,
although lapse rates are not as steep as this evening. Warm
temperatures can be expected again tomorrow, with highs well into
the 80s for most locations outside the mountains.

&&

.LONG TERM...
(Tuesday night through next Monday)
Issued at 310 PM EDT Mon Apr 15 2024

Key Messages:

1. Increasing rain chances with showers and thunderstorms Wednesday.
A break in the rain Thursday. Rain chances increase with a chance
for more thunderstorms Friday and Saturday.

2. Turning much cooler Sunday and Monday behind cold front.
Lingering rain chances through at least Sunday with slowing of
front.

Discussion:

Tuesday night the strong upper level ridge over the east and
southeast will continue to combine with a low level southerly flow
and increase warm advection into the region. After a very warm day
Tuesday and increasing clouds Tuesday evening temperatures will be
slow to fall. Lows expected in the lower to mid 60s.

An approaching low pressure system into the Great Lakes pushes a
cold front through the Tennessee Valley Wednesday. Models are
showing a weakening trend with this front as it shifts east as main
system goes far to the north. Have kept higher rain chances then
MAV/MET blend. ECMWF only model keeping the front and precipitation
widespread with the other 2 models drier. Some storms that are able
to form could still get moderate instability and shear late in the
day with ample daytime heating into the mid to upper 70s and dew
points in the upper 50s to near 60 along the plateau and southern
valley. The plateau area should see the highest risk with marginal
damage possible. The weak front should move east Wednesday night
with a dry and continued warm day Thursday as no cold air will
follow this front. Weak high pressure will slowly slide east late
Thursday and Thursday night. A new low pressure area forms across
the western southern plains Wednesday night and Thursday.

This weaker low and system will be a slower mover and ECMWF shows it
weakening as it approaches Friday night. Not much shower and
thunderstorm activity moves in with most of the convection to the
southwest of the local area. The GFS shows a little more convection
Friday but again shows redevelopment far to the west. It looks like
overrunning along the front will bring more significant rainfall
across the region Saturday and Sunday with the ECMWF and the GFS
only Sunday. With the uncertainty Have rain chances through the
weekend. Monday the front shifts east. Above normal temperatures
will continue through Friday then cooling down Saturday and much
cooler Sunday and Monday with highs only in the upper 50s to mid
60s.

&&

.AVIATION...
(00Z TAFS)
Issued at 737 PM EDT Mon Apr 15 2024

Some hi-resolution guidance continues to show a few isolated
showers/storms developing near southwest Virginia and northeast
Tennessee tonight. Have included vicinity thunder mention at TRI
but confidence is quite low in any direct impacts to the terminal.
Most likely timing seems to be through about 6z. Otherwise, mid
to high level clouds stream across the area with light winds
through TAF period.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             61  85  64  77 /   0   0  20  50
Knoxville McGhee Tyson Airport, TN  62  85  65  77 /  10  10  10  40
Oak Ridge, TN                       61  85  63  77 /   0  10  20  50
Tri Cities Airport, TN              59  81  60  78 /  20  20  10  20

&&

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

$$

SHORT TERM...DGS
LONG TERM....TD
AVIATION...KRS