Area Forecast Discussion Issued by NWS Knoxville/Tri Cities, TN
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000
FXUS64 KMRX 151411
AFDMRX
Area Forecast Discussion
National Weather Service Morristown TN
1011 AM EDT Fri Mar 15 2024
...New UPDATE...
.UPDATE...
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Issued at 1006 AM EDT Fri Mar 15 2024
Currently the initial line of showers and thunderstorms is
moving onto and east of the southern Appalachian Mountains.
Satellite data is showing that most of the lightning activity
associated with the line is south of the TN/NC state borders.
This morning update was mainly to adjust hourly PoP/Wx forecast to
come more in line with radar trends as the main line begins to
leave the area. Have not completely eliminated storm chances the
rest of the day as we could see redevelopment of much more
isolated storms in the afternoon/evening ahead of the actual
front... But have cut back on the precipitation chances across
much of the valley.-- End Changed Discussion --
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.SHORT TERM...
(Today and tonight)
Issued at 400 AM EDT Fri Mar 15 2024
Key Messages:
1. A line of showers and thunderstorms will move across the area
this morning. Bringing strong gusty winds and locally heavy
rainfall as the primary hazards.
2. More showers and some storms develop/move through this
afternoon although more scattered and continue into the evening
diminishing around midnight.
Discussion:
Early this morning convection that was over southern middle
Tennessee and north Alabama quickly moved into southeast Tennessee
and is spreading northeast up the Tennessee Valley toward
Knoxville. A strong jet was moving through the Ohio Valley and a
shortwave ahead of a frontal system moving into the Ohio Valley
this morning had developed a line of showers and storms to the
west from middle Tennessee into northern Mississippi. This will be
the main weather maker today behind the initial convection. The
storms were strongest in the past hour across the southern
plateau. The storms to the west are expected to weaken as they
approach eastern Tennessee later this morning. Behind the line
showers and storms should become more scattered this afternoon as
the more organized convection shifts south. More convection should
develop later in the afternoon and evening ahead of the front.
The instability looks to be limited later today but with
precipitable water values high some heavy rainfall is possible
through about mid afternoon mainly southern areas.
Some stronger winds are possible this morning with the storms to
as they move east and southeast today. Locally heavy rainfall
could cause isolated flooding over the southern part of the Cumberland
Plateau, southeast TN, and southwest NC...mainly this morning.
By 06Z tonight the front should be east of the Appalachians and
higher pressure will be building in from the west. Rain will end
but with all the precipitation there will be patchy fog forming.
Temperatures today will still be mild in the 60s to around 70.
Tonight lows will still be in the mild 40s to lower 50s.
&&
.LONG TERM...
(Saturday through Thursday)
Issued at 400 AM EDT Fri Mar 15 2024
Key Messages:
1. Mostly dry conditions Saturday through the end of the extended
forecast period.
2. Hard Freeze growing likely for much of the area Tuesday morning.
This would be accompanied by wind chills in the the teens for much
of the area.
Discussion:
A cold front will be east of the forecast area at the start of
extended forecast period. The upper level becomes westerly over
Tennessee this weekend. A weak front will move down from the NW early
Sunday. This front will be mostly dry but could produce a few
showers in the south and southeast mountains of Tennessee and
southwest North Carolina but amounts very light. Temperatures
will be cooler in the 60s but still above normal by a few degrees.
Monday a significant upper trough moves through the Ohio valley
and southern Appalachians. Light precip is possible over southwest
Virginia and it will be cold enough Monday night for a few snow
showers. Elsewhere it will be dry and more significant will be the
cold temperatures behind the trough and cold front Monday night
into Tuesday morning. Lows Monday night should drop into the 20s
area wide.
Wind chills are expected to drop into the teens for parts of NE
TN, SW VA, and the Cumberland Plateau. Wind chills in higher
elevations of the East Tennessee mountains may fall below 10. The
cold air will not last as higher pressure and the departing trough
bring a gradual warming trend for the rest of the week.
Next chance of rain will be Thursday as a southern system moves
across the Gulf coast area. Rain chances will be about 30 percent
later Thursday.
&&
.AVIATION...
(12Z TAFS)
Issued at 740 AM EDT Fri Mar 15 2024
MVFR conditions at CHA with a line of showers and thunderstorms
moving through during the next hour or so. TYS also has reduced
visibility due to storms with the line. TEMPO for these storms
will be for low visibilities. Storms should move out later but
MVFR conditions continue. Possible storms at TRI this afternoon
and Ceilings expected to be MVFR this morning. Later today more
thunderstorms possible ahead of a cold front that will move
through this evening. IFR conditions possible at CHA tonight and
MVFR conditions persisting elsewhere as low clouds and fog remain
after showers end during the day.
&&
.PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN 70 53 71 48 / 100 40 0 0
Knoxville McGhee Tyson Airport, TN 69 51 67 46 / 90 40 0 0
Oak Ridge, TN 70 48 69 45 / 90 30 0 0
Tri Cities Airport, TN 67 47 64 43 / 90 40 10 0-- End Changed Discussion --
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
SHORT TERM...
LONG TERM....TD
AVIATION...TD