Area Forecast Discussion
Issued by NWS Louisville, KY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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
000
FXUS63 KLMK 170150
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
850 PM EST Fri Feb 16 2018

.Forecast Update...
Issued at 850 PM EST Fri Feb 16 2018

Forecast is on track this evening. Mainly just updating to reflect
latest hourly Temp/Td/Wind trends. The main concern for the
overnight period was whether or not we could see some fog
development if skies cleared. At this point, it looks like we`ll
stay mostly cloudy through the overnight as a stratus layer
continues to undercut upper sky cover streaming in ahead of the next
system. There are some breaks in each cloud layer, but any clearing
should be transient and short-lived. Therefore, not too concerned
about the potential for overnight fog development. The latest
guidance doesn`t reflect a threat either so will continue to leave
any fog mention out for now.

Otherwise, the next focus will be on 00z model data and potential
for a brief period of snow on Saturday before p-type changes to
rain.

&&

.Short Term...(This evening through Saturday night)
Issued at 244 PM EST Fri Feb 16 2018

Rain has exited the region and is now pushing into eastern Kentucky.
The Kentucky Mesonet and various ASOS/AWOS rainfall totals since
midnight have ranged from an inch to a inch and a half across
northern Kentucky and southern Indiana, while central/southern
Kentucky have seen lighter amounts in the quarter to half inch
range. This rain has led to some rises in rivers and streams, and a
few have risen to minor flood stage.

Clouds will slowly push south this evening, and we should see a
period of mostly clear to partly cloudy skies during the overnight
hours. With relatively light winds and saturated soils, may have to
keep an eye on fog potential in areas where clearing occurs.

Clouds begin streaming in early tomorrow morning, and precipitation
may start near sunrise across parts of southern Kentucky.
Precipitation will spread northward during the morning and early
afternoon hours, though the heaviest rain will stay near the KY/TN
border. Generally looking at a half inch of rain near the KY/TN
border, while areas north of the Bluegrass/Western Kentucky Parkways
could get up to a quarter inch of rain.

We may see precipitation briefly start out as snow or a rain/snow
mix tomorrow with cold temperature profiles in place, but should
switch over to a cold rain fairly quickly. The best chance for any
snow will be across northern Kentucky and southern Indiana. The
short duration of the snow or rain/snow mix should have little to no
impacts on area roads.

The rain pushes out of the region by sunset tomorrow. Much like
tonight`s forecast, we may have to keep an eye on fog potential
tomorrow night as skies will be clearing while winds remain
relatively light. Overnight lows will fall close to the freezing
mark.

&&

.Long Term...(Sunday through Friday)
Issued at 258 PM EST Fri Feb 16 2018

...Increasing Potential For River Flooding Next Week...

As has been advertised for many days now, the pattern is still
looking to be active and very wet next week, though some questions
remain as to where the heaviest axis of precipitation will develop.
The synoptic pattern will feature a large, upper level ridge off the
southeastern US coast with troughing in the Western US. At the
surface, a cold front will gradually work from the Midwest/Central
Plains into the lower Ohio Valley over the early to mid week
timeframe next week. Deep Gulf moisture will feed into the region,
and multiple waves riding along the front will create several rounds
of moderate to locally heavy rainfall to the area. The GFS is still
targeting southern Indiana and western Kentucky for where the bulk
of the precipitation could occur, while the ECMWF/Canadian have
trended further west and now keep the heaviest rain over MO/IL and
parts of central/northern Indiana. Regardless of which solution
plays out, a widespread 1 to 2 inches of rain will probably fall
between Sunday night and Wednesday night, which would still lead to
some flooding issues. If the GFS solution ends up being correct,
amounts in excess of 3 inches would be possible across parts of
southern Indiana and western Kentucky.

Unfortunately, even more rainfall could fall Thursday into next
weekend as models show another frontal boundary stalling near the
region. Still lots of time to hone in on where the heaviest axis of
rain will fall, but the overall forecast regarding flooding is not
very optimistic.

&&

.Aviation...(00Z TAF Issuance)
Issued at 640 PM EST Fri Feb 16 2018

Have some lingering MVFR cigs across the region that should scatter
out over the evening hours. A couple of waves then will start to
approach the region overnight, bringing a return to lower ceilings
and precip chances areawide. Temperature profiles are close that
some rain or snow may mix briefly at the first couple of hours of
onset at our I-64 sites. Only had enough confidence for now to put
that mix in at HNB, but as the forecast gets closer we may add a
window for SDF/LEX. By mid afternoon all sites should be well into
the rain, with IFR conditions expected. Some improvement is possible
by the end of the period.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&

$$

Update...BJS
Short Term...DM
Long Term...DM
Aviation...RJS



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