Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 182256
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
556 PM EST Tue Nov 18 2014
...Updated Aviation Discussion...
.SHORT TERM (Now through Wednesday Night)...
Issued at 300 PM EST Tue Nov 18 2014
Afternoon satellite imagery and surface observations show mostly
sunny skies across southern Indiana and central Kentucky. Despite
the abundance of sun, temperatures remain well below seasonal
normals. Temperatures currently range from the lower 20s across the
Bluegrass and southern Indiana where the heavier snowpack remains to
the upper 20s down across far southern Kentucky. West to southwest
winds of 10 to 15 mph with occasional gusts up to 20 MPH makes it
feel much colder with wind chill readings in the upper single digits
to the lower teens. For the remainder of the afternoon, expect the
mostly sunny conditions to continue. Some stratocumulus will
continue to develop across southern Indiana and we may be able to
squeeze out a snow flurry or two. Temperatures will max out in the
next hour and then fall into the upper teens to the lower 20s by
For tonight, mostly clear skies are expected early on in the
period. Surface winds are expected to relax as well which should
allow temperatures to cool into the lower to middle teens.
Generally stuck close to the raw multi-model consensus here with the
low temperatures. Temperatures may start to climb toward dawn as
mid-high level clouds start to stream in from the west/northwest.
For Wednesday/Wednesday night, surface high across the MS delta
region is forecast to drift eastward into northern Florida. As this
occurs, a secondary wave will drop down out of the Midwest and push
a cold front toward the region. Out ahead of this front, we`ll see
an increasing pressure gradient which will allow for breezy
conditions on Wednesday with a moderation in temperatures. Highs
will likely spike into the upper 30s the lower 40s across the north
with middle 40s likely across the south. It will likely be more
windy than today with southwesterly winds of 15 to 20 mph with gusts
up to 30 MPH possible.
The front will push through the region during the afternoon hours
which will shift winds to the northwest. A few snow showers and
snow flurries will be possible mainly across our far N and NE
sections of southern Indiana. These snow showers and flurries will
likely persist into Wednesday evening across the Bluegrass. However,
with most of the moisture remaining up across central IN/OH, these
snow showers will be mainly light and might leave a dusting of
accumulation across the far northern sections of the Bluegrass
region of central KY. Lows Wednesday night will cool back into the
upper teens in southern Indiana with lower-middle 20s across KY.
.LONG TERM (Thursday through Tuesday)...
Issued at 315 PM EST Tue Nov 18 2014
Thursday - Friday...
Expect a dry forecast to end the work week as surface high pressure
will be in control and weak ridging aloft gradually builds in.
Temperatures will be cooler on Thursday behind the front with highs
only in the low and mid 30s. A few southern KY counties could touch
the upper 30s. Thursday night lows will range n the 20-25 degree
range. The surface high begins to shift NE on Friday along with
rising height and thicknesses as the upper ridge briefly builds in.
This will start the warming trend back toward normal with highs in
the upper 30s and low 40s on Friday.
Friday Night - Saturday...
A classic warming pattern takes shape as we begin the weekend with
upper level ridge axis in place and steady southerly flow on the
back side of surface high pressure. Will have to watch some light
overunning precipitation mainly across our western CWA with this
warm surge. Will also continue to mention small chances for some
light freezing rain on Friday night and Saturday morning as our far
north and east county temperatures stay just below freezing before
warmer surge arrives. This will be a close call and will lean toward
downplaying it as precipitation will have to overcome a dry airmass
in place, and temperatures will be more in the 30-32 range. Overall,
think the warm air will win out just in time, before any impacts can
be realized. Stay tuned.
The warmer sector really gets established over the area Saturday
with highs in the 50s. Will also continue to mention some scattered
showers, mainly across our west.
Saturday Night - Sunday...
Interesting setup to end the weekend and start the new week. Will
call for lows in the 45 to 50 degree range Saturday night, but with the
steady warm advection and clouds think we may be too cool. Trended
toward a smaller diurnal range. More importantly, a strong and
negatively tilted wave will move out of the southern Plains and into
the lower Mississippi Valley. The strong low level jet and
associated moisture transport will bring a lot of moisture up into
the Ohio Valley, late Saturday night and Sunday. Will continue high
rain chances during this time, and continue to include the mention
of thunder on Sunday. Will have to watch this system closely as we
will have an open gulf will bring a surface temp / dew point profile
of something like mid 60s over mid 50s. This combined with a
favorable shear profile and steepening mid level lapse rates could
lead to some low topped convection Sunday afternoon and evening. A
few rotating "storms" cannot be taken off the table in this type of
Sunday Night - Tuesday...
Models diverge at this point, but will characterize the overall
pattern by troughiness and perhaps a secondary wave bringing more
precipitation chances on Monday/Monday night. Things will cool off
during this time.
.AVIATION (00Z TAF Update)...
Updated at 555 PM EST Tue Nov 18 2014
High pressure will build across the region tonight and shift off to
the east tomorrow as a front begins to approach from the northwest.
Gusts have already died down this evening and winds will continue to
relax over the next couple of hours. Speeds of 5-7 knots are
expected overnight. Skies will be clear for much of the night. Mid
level clouds will begin to stream back in tomorrow morning ahead of
the front. Winds will pick up from the southwest during the morning
hours. Sustained winds of 12-18 knots with gusts in the 25-30 knot
range are expected through the afternoon hours.