Area Forecast Discussion
Issued by NWS Nashville, TN

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

261
FXUS64 KOHX 192320
AFDOHX

Area Forecast Discussion
National Weather Service Nashville TN
520 PM CST Mon Feb 19 2018

.UPDATE...
FOR 00Z AVIATION DISCUSSION.

&&

.DISCUSSION...

Windy and warm. Those are the words for the day. Temperatures
have already climbed into the mid 70s for most (low to mid 60s on
the Plateau). At forecast time, we`re sitting at 75, however we
did reach 76 at BNA at 1221 pm CST this afternoon. More records
are likely to fall over the next 24-36 hours, both for highs and
lows.

There are a few changes to the forecast package from yesterday, the
biggest being the upcoming weekend.  Let`s start with the mid-week
rain maker first.

An active forecast is still in the works. Models continue to be very
consistent bringing moderate to heavy rainfall into Middle TN
Wednesday into Thursday.  The biggest question mark is going to be
the cold front Wednesday night -- how fast is it going to move, how
far south will it get -- and that`s really going to drive the
overall flood concerns in the short term.  Models are in decent
agreement that the cold front will make it about half way through
the mid-state by Thursday morning and then return northward Thursday
evening as a warm front.  This could very well become problematic in
the rainfall category, especially if the front becomes more quasi-
stationary versus making a full retreat back to the north.  Areas
west of I-65 and north of I-40 are already going to be under the gun
for localized flooding issues and rises on creeks and rivers, but if
that front doesn`t return northward quick enough, we could have a
worse situation in the making.  For now, we`ll continue to highlight
the potential for 1-3" across Middle TN between Wednesday and
Thursday, with the highest values in the aforementioned areas.

By the end of the workweek, there`s still some details to be worked
out.  The GFS is holding onto the bulk of the rainfall being this
weekend, however, the latest Euro is suggesting additional
rainfall Friday night, which is beefing up rainfall totals even
more. This is a new twist, so I`m not going to grab a hold of
this just yet, but what is different in both models is the weekend
rain. The system that I was observing yesterday for this weekend
has now become more dynamic in its features. Two things happen
because of this: first, rainfall totals aren`t quite as high. Not
by much (still 1-2 inches), but not as high. The second thing it
does is allow for more surface based instability and wind shear to
develop. Because of this, both the GFS and the Euro are
suggesting some strong storms could develop Saturday evening. This
is likely the reason SPC has included SW portions of the mid-
state in their Day 4-8 outlook for Saturday. Bottom line, it`s
going to rain this weekend. The question now is, is it just going
to be soggy or are we going to have to deal with winds, too? We`ll
work that out as we move through the week. For now, we`ll focus
on the Wednesday/Thursday rainfall and flood potential, continuing
to highlight this in the Hazardous Weather Outlook and add the
strong wording in tomorrow, if these features persist.

&&

.AVIATION...
00Z TAF DISCUSSION.

VFR conditions are expected through the TAF period at CKV/BNA/MQY
but will continue mention of wind shear at 2000 feet due to a
strong low level jet of 45-50 knots. VFR conditions are
anticipated tonight at CSV but MVFR cigs will develop by Tuesday
morning. South winds up to 11 knots overnight will increase to 10
to 20 knots with gusts up to 30 knots on Tuesday.


&&

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

&&

$$

DISCUSSION......Unger
AVIATION........Shamburger



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.