Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN

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FXUS64 KMRX 180143 AAA

National Weather Service Morristown TN
943 PM EDT Thu Jun 17 2021




Just a few adjustments to hourly temp/dewpoint grids are needed
this evening. A tranquil pattern continues with a dry northerly
flow through the mid and upper levels, and a surface high pressure
ridge over the central Appalachians and Mid-Atlantic region
extending SW. Lows will range from the mid 50s north to lower 60s




Clear and calm conditions will prevail at all TAF sites through
the forecast period



/ISSUED 328 PM EDT Thu Jun 17 2021/
SHORT TERM...(Tonight and Friday)...

Key Messages:

1) Dry weather continues tonight and on Friday.

2) Near to above normal temperatures tomorrow.


Northwest flow aloft continues to promote a drier airmass today
while a northern stream disturbance drifting across southern
Canada and the northern plains suppresses the ridge axis to the
east across the Great Lakes and midwest. Surface high pressure
remains situated across the mid Atlantic and extends across the
Southern Appalachians/Tennessee Valley.

Dry weather is expected underneath increasing heights and high
pressure at the surface tonight and again on Friday. Lows tonight
will likely be slightly warmer than last night although some
locations will likely see below normal temperatures overnight. On
Friday, heights increase further with an increase in 850mb
temperatures. Highs on Friday will be several degrees warmer than
today as highs approach the upper 80s to lower 90s across much of
the area.


LONG TERM...(Friday night through Thursday)...

-Mostly dry and quite warm to start the period

-More unsettled pattern for Sunday into Tuesday, but details still

-Drier and cooler for the end of the period

We start the period with surface high pressure to our east still
extending into our area between a cold front well to our north and
the Gulf low, which may be a tropical system by that point, still
well to our south/southwest. Friday night should be dry and most
areas will likely stay dry on Saturday as well, although models do
indicate there may be enough convective energy for some isolated
afternoon showers/thunderstorms so will keep the slight chance PoPs
for the afternoon hours. It will be quite warm saturday with highs
near to a bit above seasonal normals.

Models continue to struggle with the Gulf low/possible tropical
system that may affect our area around the Sunday/Sunday night time
frame. The operational models generally keep most of the heavier
rain to our south, but given that some of the ensemble data still
shows heavy rain across mainly southern parts of our area as well as
the inherent forecast track uncertainty that far out will keep the
mention of possible heavy rain/flooding in the HWO. Will carry
chance to likely PoPs with the highest PoPs south/southeast for
Sunday and Sunday night. Behind this system models again are
struggling with the details of the upper trough/cold front that
moves in but are trending toward better agreement on timing. The
front will likely pass through our area sometime in the Monday
night/Tuesday time frame, so will carry significant PoPs for showers
and thunderstorms through Tuesday.

Drier and cooler air should move in behind the front for the latter
part of the period, so will keep things dry Wednesday into Thursday.



Chattanooga Airport, TN             65  93  69  88  69 /   0   0   0  20  30
Knoxville McGhee Tyson Airport, TN  61  91  67  90  67 /   0   0   0  20  20
Oak Ridge, TN                       60  89  68  89  68 /   0   0   0  20  10
Tri Cities Airport, TN              55  88  60  88  63 /   0   0   0  20  10



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