Area Forecast Discussion
Issued by NWS Louisville, KY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS63 KLMK 200225

Area Forecast Discussion
National Weather Service Louisville KY
925 PM EST Fri Jan 19 2018

.Forecast Update...
Updated 925 PM EST Fri Jan 19 2018

GOES 16 nighttime microphysics scans showing low clouds pushing
northeastward out of Tennessee this evening.  Cloud cover also
evident in looking at KY Mesonet observations.  Where clouds have
moved in, temperatures have leveled off in the upper 30s to near 40.
However, where skies have cleared, temperatures are in the upper 20s
to the lower 30s.  Short term model guidance is capturing the low
cloudiness well, just above the 850 hPa level.  This low-level
moisture is expected to continue to advect northward and we expect
skies to continue to cloud up from the SW to the NE overnight.

With that said, have made some minor adjustments to the overnight
temperatures and raised them a few degrees as the expected
cloudiness will limit the temp drop.  We`ll likely see lows for the
day around midnight (before the clouds get too thick), and then it
would not surprise us to see temps warm and stabilize a bit for the
remainder of the overnight period.


.Short Term...(This evening through Saturday night)
Issued at 237 PM EST Fri Jan 19 2018

Low clouds streaming northeastward from Texas into the lower
Mississippi Valley will continue to surge forward, moving into
central Kentucky after midnight and spreading throughout the region
Saturday. As the day progresses, low level moisture will continue to
increase and thicken. By evening and into Saturday night patchy
light rain or drizzle will be possible in a good low level moisture
feed behind high pressure off the SC/GA coast.

Temperatures have peaked a few degrees either side of 40 this
afternoon, and 40s will be attainable tomorrow despite cloud cover.
Temperatures will remain above freezing Saturday night so any
precipitation will stay liquid.

.Long Term...(Sunday through Friday)
Issued at 248 PM EST Fri Jan 19 2018

Low pressure over Kansas on Sunday will head to the Great Lakes
Monday/Monday night and swing its attendant cold front through the
Ohio Valley. Though a few showers will be possible in the warm
sector Sunday and Sunday night, by far the best chance of rain will
come Monday and Monday night in association with the frontal
passage. A rumble of thunder will be possible, but otherwise
instability looks limited.

There will be plenty of wind with the system, though, and surface
gusts will likely top 30mph. Those winds, plus the fact that the
ground will be bare by then, will bring temperatures up to near 60.

QPF values have trended lower over the past few days, with expected
amounts now in the one-third to one-half inch range. As a result,
flooding is not expected.

We`ll return to dry weather for most of the rest of the work week as
high pressure builds in and slowly moves through the area. Flow
transitioning from zonal to ridge east/trough west will help keep
temperatures near or above normal through the period, rather than a
return to the deep freeze.


.Aviation...(00Z TAF Issuance)
Issued at 620 PM EST Fri Jan 19 2018

Stratus deck moving in from the southwest will impact all TAF sites
at some point this evening into early tomorrow morning. Based on
upstream obs, appears we should keep ceilings in the VFR range. LLWS
will also increase tonight as a +45kt LLJ and inversion develop.
Ceilings should gradually lower to MVFR tomorrow morning after
sunrise across most TAF sites as more moisture works in from the
southwest. Expect the cloudy skies to stick around through the
duration of the TAF period.




Short Term...13
Long Term....13
Aviation.....DM is the U.S. government's official web portal to all federal, state and local government web resources and services.