Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 070845
Area Forecast Discussion
National Weather Service Louisville KY
345 AM EST Wed Dec 7 2016
.Short Term...(Today through Thursday)
Issued at 305 AM EST Wed Dec 7 2016
...Strong Cold Front to Bring Sharply Colder Air Tonight...
Partly to mostly cloudy skies are expected today ahead of an
approaching cold front. High temps will be cooler than yesterday
ranging through the 40s.
Tonight a mainly dry cold front will pass through the region
ushering in a much colder airmass. In contrast to previous model
runs, the 0Z runs went largely dry with the fropa. Given the very
dry initial airmass and lack of moisture with this front, went ahead
and removed the small chance of POPs we had near the KY/TN border.
However, in coordination with other offices, decided to keep a
slight chance for sprinkles and/or flurries late tonight into Fri
morning for south central and east central KY. Low temps will range
through the 20s tonight as the colder airmass moves in.
For Thurs, expect skies to turn only partly cloudy early in the day.
However, temps will still only be able to reach the 31-38 degree
range despite any sunshine!
.Long Term...(Thursday night through Tuesday)
Issued at 330 AM EST Wed Dec 7 2016
...Unseasonably Cold Later This Week...
Thursday Night - Friday...
Added a slight chance for flurries on Thu night into early Fri in
coordination with JKL as a vort max rounding the base of the broad
upper level trough may provide just enough forcing to squeeze out a
few flurries from the low level cloud deck. Soundings show a decent
low level moisture plume reaching -10 to -12 degrees C aloft so ice
nuclei will be present. Temps Thurs night will bottom out in the
upper teens to around 20 degrees with highs on Fri only recovering
into the upper 20s/lower 30s.
Saturday - Monday...
The unseasonably cold air will continue through Sat with teens for
lows Sat morning and highs in the 30s Sat afternoon.
Another weather system will move into the area Sat night and Sun
possibly extending into Mon as well if the 0Z ECMWF is correct with
an additional wave riding along the front. Long range model
consensus puts the best precip chances on Sun for now. Will
continue a low POP into Mon.
As far as ptype, precip could start out as a mix of rain/snow very
early Sun morning before transitioning to all rain Sun with highs
reaching the 40s. QPF amounts look to range from 0.10-0.5 for this
system. Late Sun night into Mon morning, we could see a transition
back to a rain/snow mix as temps cool below freezing. Depending on
how long the moisture lingers and if there is a second wave will
determine if we see any transition to mainly snow Mon morning before
precip ends. There is low confidence with this weather system as
many long range model solutions exist.
Late in the day Tues into Tue night another weather system will
enter the region which may again bring another rain/snow mix as well
as another shot of colder air.
.Aviation...(06Z TAF Issuance)
Issued at 1203 AM EST Wed Dec 7 2016
The challenge for the overnight period of this TAF forecast will be
when the stratus deck will scatter out. Sites in southern IN have
already seen low clouds move out. They should scatter out at SDF by
07Z or so. Low clouds will hang around BWG and LEX until 10-12Z.
Through the remainder of the day cirrus will stream across the
region. This evening a mid deck will build back in as the next
disturbance moves through.
Some light fog may be possible early this morning at LEX and BWG,
though low clouds may hang around long enough that this will not be
an issue. Winds will be generally fairly light through this TAF
period and out of the northwest to north.