Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 130151
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
851 PM EST Thu Jan 12 2017

...Updated Forecast Discussion...

...Forecast Update...
Issued at 850 PM EST Thu Jan 12 2017

Post frontal shield of light to occasionally moderate rain showers
will continue mainly along/south of Ohio River through the remainder
of the evening. Have updated precipitation chances to reflect this
activity.

As for freezing rain potential early Friday morning, feel this
threat has low probability, isolated and mainly confined to portions
of southwest Indiana where 1) there might still be some overrunning
precipitation around dawn and 2) temperatures will be marginally at
or below freezing. However, road temperatures remain warm and
haven`t responded too much to the cold air surge from today. As a
result, will maintain current SPS through the morning commute.

One other concern is the possibility of isolated black ice forming
on road surfaces from residual moisture from today. Below freezing
temperatures are expected for southern, southeast Indiana and
portions of north central KY and the Bluegrass. If there`s any
lingering moisture around, that could result in some black ice.
Steady winds should help dry out most surfaces the remainder of the
night, but couldn`t rule out some isolated problems for the morning
commute.

Finally, brought up precip chances for late morning and afternoon
tomorrow as next wave of rain showers moves through the area. Pretty
good consensus in the hi-res and short-term models of this lifting
north/northeast across the area, so brought PoPs into the 60-80
percent range.

Issued at 610 PM EST Thu Jan 12 2017

Updated precipitation chances in the near term /this evening/ to
account for coverage of post-frontal showers spreading across
southern Indiana and northern Kentucky. Also trimmed back chances in
the near term across the far southeast areas /Lake Cumberland
region/ for a slower arrival of the leading line of showers
associated with the frontal passage.

Otherwise, forecast through this evening is on track.

.Short Term (Now through Friday Night)...
Issued at 259 PM EST Thu Jan 12 2017

The cold front is currently making its way through the region. A
narrow line of gusty showers along the front will continue to move
through central Kentucky over the next few hours. Behind the front,
temperatures will quickly fall into the upper lower 50s to upper
40s.

The main concern for tonight will be whether there will be any
chances for freezing rain. Some light showers will be possible
behind the front but they should move out before freezing
temperatures can make their way in. The latest mesoscale models have
come in much drier for the overnight period. Thus, have taken pops
out of the forecast completely for much of the overnight hours for
southern Indiana and portions of north central Kentucky. The
freezing line looks to remain generally north of the I-64 corridor.
Thus, the precipitation should mainly stay to the south of the
freezing temperatures. However, rain starts to move back to the
north tomorrow as another wave moves in and there could be a brief
period of freezing rain before temperatures warm into the mid to
upper 30s. The main concern for this will be in southwestern
portions of southern IN. May issue an SPS for this, but otherwise,
freezing rain tomorrow morning does not look to be much of a problem
for this time frame, especially given how warm road temps are
currently.

Temperatures will stay on the colder side during the day Friday.
Highs will generally be in the upper 30s to mid 40s. Temps should
start to fall to near freezing across our northern tier of southern
IN counties (generally Dubois to Jefferson counties in IN) by 03Z
Saturday. Thus some light freezing rain will be possible in this
region tomorrow night with some light ice accumulations of a few
hundredths possible.

This is a complicated forecast as the region remains right on the
edge of the colder air. A few degrees in either direction could
result in a bit more ice or none in southern IN over the next couple
of nights. Close attention should be paid to updates over the next
couple of days.

.Long Term (Saturday through Thursday)...
Issued at 313 PM EST Thu Jan 12 2017

Saturday through Sunday Night...

The stalled boundary asross the region will remain in place through
the weekend. Rounds of showers will move through as waves ride along
this boundary. Temperatures will be close to freezing across
Jefferson county IN Sunday morning, so some light freezing rain
can`t be completely ruled out. However, if any occurs it should be
brief and any impacts mitigated by temps warming above freezing
Sunday. We may finally get a break in the rain on Sunday night as
the boundary lifts to the north as a warm front thanks to a low
pressure system beginning to eject out of the southwest. Temps will
vary quite a bit across the region through the weekend with highs
across southern IN in the lower 40s and highs across south central
KY in the mid to upper 50s.

Monday through Thursday...

Monday the lower Ohio Valley should be solidly in the warm sector
with just scattered showers developing during the day. High
temperatures will once again be well above normal in the lower to
mid 60s. Rain chances will be on the increase Tuesday into Tuesday
night as the cold front associated with a low pressure system making
its way into Canada moves in. We could see a few rumbles of thunder
on Tuesday as well. The boundary then looks to stall across the
region on Wednesday with rain continuing. Precipitable water values
continue to look like they will be near record levels. With the
amount of rain and saturated grounds, flooding may become an issue
by mid week.

&&

.Aviation (00Z TAF Update)...
Updated at 605 PM EST Thu Jan 12 2017

A sharp cold front will have passed through all central Kentucky TAF
sites by 00z. Post-frontal showers will spread across SDF and LEX
through mid-evening, and across BWG into the early overnight hours.

Lower ceilings will drop south across the area this evening and will
likely set up in the 800 to 1200 ft range. As the front hangs up
around the KY/TN border, low-level moisture will give way to drizzle
at times at BWG while slightly drier air will keep a scattered to
broken ceiling in place.

Another weather system will bring more showers to the area in the
late morning and afternoon hours. IFR to low-end MVFR ceilings and
some visibility restrictions are likely during this time frame.

&&

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

$$

Update.........ZT
Short Term.....EER
Long Term......EER
Aviation.......ZT



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