Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 150723
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
323 AM EDT Tue Apr 15 2014
.SHORT TERM (Now through Wednesday)...
Issued at 310 AM EDT Tue Apr 15 2014
Post frontal precipitation continues to stream across the area ahead
of the upper level trough axis set to swing through later today. The
main concern early this morning will continue to be precipitation
type as this last batch of precipitation exits the area. Enough low
level cold air is being advected into the region behind the cold
front to get some sleet and snow mixing in with the rain. Ground and
road temperatures are too warm for any problems to occur, but will
continue mention in the forecast as a dusting could occur on
elevated surfaces through the morning hours.
Precipitation will exit our east by late morning with continued
gusty NW winds. Skies will also begin to scatter out by late morning
and through the afternoon hours, however temperatures will struggle
only to the low and mid 40s.
...Hard Freeze Tonight...
Surface high pressure will build into the Ohio Valley overnight,
with mostly clear skies and nearly calm winds. Dew points will be
down around 20 degrees, and with good radiational cooling conditions
temperatures will fall rapidly after sunset. Temperatures are
expected to bottom out in the mid and upper 20s, with several hours
below freezing. A few lower 20s are even possible in our far eastern
valleys. Due to the hard freeze, have upgraded the Freeze Watch to a
Freeze Warning in coordination with surrounding offices.
The pattern will shift to southwest flow aloft with surface high
pressure scooting off to our east on Wednesday. Mostly sunny skies
will result in temperatures trying to moderate despite the slow
morning start. Highs should be able to reach into the mid and upper
50s by mid to late afternoon.
.LONG TERM (Wednesday Night through Monday)...
Issued at 323 AM EDT Tue Apr 15 2014
Wednesday Night through Friday Night...
A broad southwesterly flow aloft is forecast to be in place across
the Ohio Valley at the start of the period with surface ridge axis
located east of the region. This will keep the Wednesday night and
Thursday portion of the forecast dry. Low temperatures Thursday
morning will be quite chilly again and some patchy frost will be
possible across the eastern Bluegrass region. Lows look to cool
into the middle 30s across the west and central sections of the
state with lower 30s in the Bluegrass region. Temperatures on
Thursday will likely be slightly warmer than what the current model
guidance suggests. Afternoon readings Thursday will likely warm
into the middle to upper 60s under mostly sunny skies. Clouds will
be on the increase Thursday night with lows falling back into the
A low amplitude mid-level wave and associated surface cold front is
forecast to impact the region on Friday. Moisture return ahead of
this feature is not expected to be all that much. Overall dynamics
are fairly weak as well. Nonetheless, forcing along and in advance
of the boundary will likely result in scattered convection
developing. In general, rain showers with a few thunderstorms still
looks like a very good bet during the day on Friday with
precipitation diminishing rapidly Friday night from west to east.
Highs Friday will warm again into the middle 60s with overnight lows
Friday night cooling back into the lower-middle 40s.
Saturday through Monday...
With the trough pulling off to the east, we`ll see a temporary ridge
of high pressure move in aloft on Saturday and into Sunday. Latest
trends in the numerical data suggest the weekend will be a bit drier
than previously forecast. We`re not all that surprised as the
models typically exhibit a progressive bias in the extended period.
With the relative good agreement here, have gone more optimistic
with the forecast for the weekend keeping Saturday and Sunday dry.
Temperatures will be slightly below seasonal normals with readings
in the lower to middle 60s. Sunday could be slightly warmer in
later forecasts if the ridge is a little stronger and we end up
getting more sun than forecast. Another quick moving mid-level wave
will push in from the west by Monday bringing another round of
showers and storms to the region. Temperatures still look to remain
in the lower-mid 60s for Monday with overnight lows through the
period in the upper 40s to the lower 50s.
.AVIATION (06Z TAF Update)...
Issued at 111 AM EDT Tue Apr 15 2014
Cold front has moved through the TAF sites at this hour as surface
winds are all sharp out of the northwest. Expect sustained winds to
continue around 10-20 mph, with gusts up around 25-30 mph. Post
frontal rain showers and drizzle should continue for another 2-3
hours at SDF/BWG and until just before dawn at LEX. Could see some
-SN and PL mix in at LEX around dawn and perhaps an hour or two of
PL at SDF around 2-4 AM EDT.
Otherwise, the other concern will be low ceilings through the
remainder of the overnight until around dawn. Currently, low MVFR is
prevailing and think this will generally be the rule for most of the
overnight as low level winds remain strong and keep the boundary
layer mixy. Can`t rule out some brief periods of IFR, especially at
LEX. Otherwise, ceilings begin to raise and scatter out later this
morning, with northwest winds continuing between 10-15 and gusting
up in the 20-25 mph range. Skies become clear and winds go light and
variable tonight as surface high pressure builds in.
KY...FREEZE WARNING from 9 PM EDT /8 PM CDT/ this evening to 11 AM
EDT /10 AM CDT/ Wednesday FOR KYZ023>043-045>049-053>057-
IN...FREEZE WARNING from 9 PM EDT /8 PM CDT/ this evening to 11 AM
EDT /10 AM CDT/ Wednesday FOR INZ076>079-083-084-089>092.