Area Forecast Discussion
Issued by NWS Jackson, KY
FXUS63 KJKL 241238 AAA
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
738 AM EST Tue Jan 24 2017
Issued at 738 AM EST TUE JAN 24 2017
Freshened up the hourly temperatures and dew points through noon.
The diurnal rise will be slow this morning, as low clouds and
areas of drizzle/light rain only gradually diminish through early
this afternoon. Updates have been sent.
.SHORT TERM...(Today through Wednesday)
Issued at 353 AM EST TUE JAN 24 2017
The latest surface map features deep low pressure off of the
southern New England coast, with a weak and broad area of high
pressure crossing the Mississippi River. Another area of low
pressure can be found at the front range of the Rockies in eastern
Colorado. Aloft, troughing is found in the eastern and western
Conus, with short wave ridging in the middle. Light rain/drizzle
is currently ongoing in eastern Kentucky, as upslope flow
continues. Temperatures range from the upper 30s west of I-75 to
the low to mid 40s in the east.
The light precipitation will be on a gradual demise from west to
east through this morning, as high pressure works in from the west.
Mostly cloudy skies will hang on through the majority of the day,
keeping highs only around 5 to 7 degrees warmer than the lows
this morning. Clearing will work in tonight as short wave ridging
moves overhead. Return flow will be ensuing overnight as well, as
low pressure deepens and moves northeast across the southern
Plains and into the Midwest. This will allow for valleys to
decouple, with some lower 30s likely, while ridgetops stay closer
to the 40 degree mark.
Low pressure will continue its trek into the southern Great Lakes
region on Wednesday, dragging a cold front towards the Ohio and
Tennessee valleys. POPs have come up quite a bit by Wednesday
afternoon, with a good chance of showers for most locations by
late in the day. One last day of 60 degree temperatures will be on
tap thanks to the gusty southwest winds in place out ahead of the
approaching cold front.
.LONG TERM...(Wednesday night through Monday)
Issued at 320 AM EST TUE JAN 24 2017
A pattern change is fully underway Wednesday night as a longwave
trough shifts eastward into the Ohio Valley. Ushering in this
change will be a cold frontal passage Wednesday night. Models are
trending wetter with this frontal passage and went along with the
blended guidance raising PoPs from previous forecast Wednesday
evening. A dry slot moves in behind the front late Wednesday night
before some deeper moisture works back in along with the 500 mb
trough axis during the day Thursday. With marginally cold air
filtering into the area, some mixed rain and snow showers are
possible on Thursday.
Once established, the upper level trough remains locked in place
through the remainder of the long term period with multiple
disturbances dropping southeastward into it`s base. The
disturbances will bring periodic chances for light showery precip
and most of this should fall in the form of light snow showers and
flurries. However, the airmass is not terribly cold and surface
temps are expected to warm above freezing each day, so will allow
for a mix of rain and snow at times as well, especially over the
Upper Cumberland. Models have trended stronger with a shortwave
dropping into the Ohio Valley Sunday into Sunday night and this
may prove to be our best shot at potentially some light snow
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
ISSUED AT 738 AM EST TUE JAN 24 2017
IFR or worse ceilings will gradually raise up from west to east as
light precipitation comes to an end through early this afternoon.
VFR conditions will return by late this afternoon into early this
evening as clouds scatter out. Some patchy dense fog will likely
be seen in the deeper river valleys between 06 and 12z; however,
will keep any visibility restrictions out of the TAFs for now.
A strengthening low level jet will allow for a small window of
wind shear west of I-75 by around 09z. Surface west to northwest
winds of 5 to 10 kts will gradually back to the west southwest
and eventually the south southeast late in the period.