Scientific Forecaster Discussion
fxus63 klmk 121300
Area forecast discussion
National Weather Service Louisville Kentucky
800 am EST Tue Nov 12 2019
issued at 800 am EST Tue Nov 12 2019
Early morning visible imagery shows back edge of cloud cover working
east of the I-65 corridor. Based on time-height cross sections, we
expect this cloud deck to continue to move eastward, but our eastern
forecast area will likely see a bit of cloudiness through the early
afternoon hours. Underneath this deck of stratus, snow flurries
will be possible. Will add snow flurries to the ongoing forecast
east of I-65 for the next few hours and then gradually shift the
flurries eastward through the Bluegrass into the early afternoon
hours. Overall fetch of Lake Michigan looks to align with our
northeastern Bluegrass counties through the afternoon hours.
Given that the significant precipitation is over, the Winter Weather
Advisory will be allowed to expire at 800 am EST. Updated
forecast products are in production and will be available shortly.
Short term...(today and tonight)
updated at 300 am EST Tue Nov 12 2019
Surface high pressure centered over Kansas maintains a tight
pressure gradient with a low over New England. This gradient is
going to force a north wind between 10 to 15 mph through the region
this morning, and it's making the surge of Arctic air behind
yesterday's front feel even colder. Morning wind chills, for those
at the bus stop, drop to single digits as far south as the Tennessee
border. Areas in southern Indiana could see below zero wind chills.
The drier air mass will help to clear skies and provide sunshine to
the area, but it won't do much for warming. The Bluegrass region
will take a little longer to clear out, but skies will likely clear
by this evening.
The upper flow will push the surface high (that is currently
centered over kansas) over southern Indiana and central Kentucky
tonight. This will help to calm winds and veer them to the east by
12z Wednesday morning.
Temperatures today will only see the 20s for highs, and tonight's
lows will only see the teens.
Long term...(wednesday through monday)
updated at 310 am EST Tue Nov 12 2019
The extended can be summed up in two words: cool and dry...or cold
and dry, if you prefer. In the wake of the just-completed snowfall,
surface high pressure and northwest flow aloft will work in tandem
to keep the region dry with temperatures below normal into next
week. While a decent upper level trof does manage to work its way
down the northwest flow into the Ohio Valley Thursday night, the
system will have virtually no moisture to work with, and for now
looks to come through dry.
Temperatures during the period will moderate from the mid 30s to
lower 40s for highs on Wednesday to near climatological norms in the
mid 50s by next Tuesday. Lows will be in the 20s through the
weekend before warming into the 30s for the first half of next work
Aviation...(12z taf issuance)
issued at 604 am EST Tue Nov 12 2019
Gusty winds from the north continue and will last for most of the
day. The uncertainty is trying to figure out how quickly the
stratus layer is going to move east and uncover Lex. Sdf and bwg
should be returning to VFR conditions shortly. Lex could take until
18z or longer.
issued at 320 am EST Nov 12 2019
The very cold air mass behind the Arctic front will threaten record
low maximums, record lows, and record snow across the region
through Wednesday morning.
Record low maximums
Date sdf Lex bwg
Nov 12 32/1932 28/1932 32/1911
Date sdf Lex bwg
Nov 12 17/1995 14/1911 17/1894
Nov 13 16/1986 13/1911 13/1911