Area Forecast Discussion
Issued by NWS Nashville, TN

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000
FXUS64 KOHX 170843
AFDOHX

Area Forecast Discussion
National Weather Service Nashville TN
343 AM CDT Thu Aug 17 2017

.DISCUSSION...

Fropa will occur late tonight so convection will be on the increase
by this afternoon and evening. Despite the amplified cape values and
a 20 kt 850 mb flow, the organized pre and immediate frontal forcing
could be better. We see a rather marked decrease when we compare
current omega fields over MO versus omegas over the mid state this
afternoon and evening. Therefore, I will include pops of course but
will slightly undercut mav guidance and include 50 percent northwest
to 30 percent east. Furthermore, Hrrr solution supports the
undercut. A few of the storms could reach strong levels this
afternoon and evening, particularly across western areas where capes
are higher.

Behind the fropa, models now leaning toward more of a prolonged dry
spell. The gfs now shows a considerable dip in mrh values and this
will equate to a rather low cape to cap ratio. The even better news
is that this trend may extend into Monday, the big eclipse day. To
offer support to the gfs solution, the euro also shows rather meager
mrh values around 50%. I would also like to point out that on both
the gfs and euro solutions at 18z, notable 80%+ mrh levels are not
found over any portion of the southeastern quadrant of the United
States. This tells me that Monday may very well be a partly cloudy
day with 70 percent of the viewing area being in good shape to view
the eclipse. It just depends on where those sct cu clouds are
located. I must say though that there does appear to be an increase
in the higher level moisture by mid week. Will need to watch out for
the high clouds. Models do show an increase in convection to our
west early next week. Westerlies may transport some cirrus blowoff
our way. Pops will increase to around 30% by Tues and Wed as the
humidity and moisture depth levels both increase.

Temps will run a few degrees above normal though the next 7 days
with highs lower 90s and lows lower 70s. Friday nt will be the one
exception as lows dip into the upper 60s with the drier post frontal
air.

&&

.AVIATION...
06Z TAF DISCUSSION.

Showers have come to an end leaving high clouds over portions of
the mid-state. I don`t see any indications of isentropic lift
later tonight, so a cloud deck shouldn`t be an issue in the
morning. However, with continued low-level moisture, reduced
visibility could be a problem at KCKV/KCSV. Have included some IFR
vis around sunrise.

Winds will be light to calm overnight and pick up out of the
southwest late Thursday morning with gusts of 15-20 kts.


&&

.PRELIMINARY POINT TEMPS/POPS...
Nashville      90  74  90  68  92 /  50  40  10  10  10
Clarksville    89  72  90  65  91 /  50  30  10  10  10
Crossville     85  71  84  64  87 /  40  50  30  10  10
Columbia       90  73  90  66  92 /  40  30  10  10  10
Lawrenceburg   90  73  90  66  92 /  40  50  10  10  10
Waverly        88  72  90  66  91 /  50  30  10  10  10

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

DISCUSSION......21
AVIATION........07



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