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

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FXUS64 KMRX 171908
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
308 PM EDT Wed Jul 17 2019

.SHORT TERM(Tonight and Thursday)...Remnants of Barry continues to
push across the Southern Appalachian Region this evening. A stray
rumble of thunder is possible this evening but the threat of a
strong or severe storm is quite minimal. The main threat continues
to be heavy rainfall and the potential for localized
flooding/flash flooding. Showers are moving at a reasonable rate
so areas of concern will be locations that receive multiple rounds
of rain. Recent relatively dry conditions have kept river level
low. The widespread rains are expected to increase river levels
but do not foresee significant problems with river flooding.
However...a few low lying areas could see brief minor flooding.
Another round of convection is expected to move in tonight into
Thursday. This is in response to a upper trough axis sliding in.
The air mass will be weakly unstable....DCAPE values should range
form 500-1000 J/Kg. This combined with diurnal heating could
produce a stray strong storm. However...the main threat will
continue to be heavy rains and the potential for isolated flash
flooding. PWs will remain high...generally between 1.50 and 2
inches and with a wet ground from today`s showers...additional
rainfall will maintain the threat of local flooding/flash
flooding. With increased sunshine on Thursday...highs will climb
back into the mid 80s to low 90s over most valley locations. Heat
indices could reach to near 100 degrees over southern
area...generally around CHA.

.LONG TERM (Thursday night through Wednesday)...Models are in
decent agreement overall for the long term period. A broad
mid/upper level ridge will be over the region for Friday into
Saturday, but models indicate quite a bit of moisture will linger
over the area so expect isolated to scattered showers and
thunderstorms around especially during the afternoon/early evening
hours. A few storms may be strong with gusty winds and very heavy
rainfall both days. Dew points will be high and it will be hot
both days, but right now it looks like heat index values will stay
below advisory criteria.

By Sunday the ridge will start breaking down with a bit better
coverage of showers and storms, then by Monday a mid/upper level
trough will be replacing the ridge and a cold front will be moving
in. Will carry the highest PoPs of the period on Monday, and again a
few storms may be strong. The front is forecast to move south and
east of our area Tuesday, with drier and somewhat cooler air moving
in behind the front for Wednesday.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             73  91  74  92 /  40  40  20  20
Knoxville McGhee Tyson Airport, TN  72  89  72  91 /  50  40  20  20
Oak Ridge, TN                       72  89  74  91 /  50  40  20  20
Tri Cities Airport, TN              70  86  69  90 /  60  50  20  20

&&

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

$$

MJB/LW


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