Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 130506
Area Forecast Discussion
National Weather Service Louisville KY
106 AM EDT TUE OCT 13 2015
...Updated Aviation Discussion...
Issued at 751 PM EDT MON OCT 12 2015
Leading line of convection now extends from roughly Georgetown, KY
to Cave City to Franklin. We did have some respectable velocities as
it moved into central KY, with measured wind speeds near 40 mph in a
few spots. However, with the loss of heating this line is no longer
organized enough to mix down any of the stronger winds aloft.
Precip is coming to an end over southern Indiana, and will taper off
from NW to SE as the evening progresses. Will do tweaks to the
forecast over the next couple hrs to refine the timing, and also
tone down the mention of strong storms in the Hazardous Weather
.SHORT TERM (Now through Tuesday Night)...
Issued at 313 PM EDT Mon Oct 12 2015
In the near term, partly to mostly sunny skies were noted across the
forecast area. NWS and Ky Mesonet observations revealed
temperatures mainly in the upper 70s across the region. A few 80+
degree readings were noted across western KY and at Louisville.
A surface cold front was located out to the west of the region this
afternoon. The front is making progress to the east, albeit a
little slower than the models initially progged yesterday and last
night. The latest guidance continues to suggest that convective
initiation will occur along the front in the next few hours out to
the west. Convection should grow upward as combo of temps in the
upper 70s and dewpoints in the upper 50s will yield around 800-1000
J/Kg of CAPE for convection to feed on. Convective initiation looks
to be in the 21-22Z time frame and then spread quickly eastward
through southern IN and central KY. Given that the stronger
dynamical forcing is north and better moisture is to our south,
convection is not likely to be severe. However, given the wind
fields aloft and sufficient DCAPE, the strongest storms this
afternoon/evening will be capable of producing some gusty winds and
possibly some small hail.
Convection is expected to diminish by mid-evening and drier air will
filter in late this evening and overnight resulting in skies
clearing out and winds shifting to the west. Overnight lows look to
cool into the upper 40s to around 50 in most locations.
Dry and cool weather is expected on Tuesday as high pressure builds
in from the west. Afternoon highs will top out in the mid-upper 60s
in the north with upper 60s to lower 70s in the south. West winds
will be breezy during the afternoon. Mostly clear skies are
expected Tuesday night with lows dropping into the upper 30s in the
typical colder spots and lower 40s elsewhere.
.LONG TERM (Wednesday through Monday)...
Issued at 251 PM EDT Mon Oct 12 2015
A broad trough will remain in place across the northeastern CONUS
through the long term period. At the surface we will see alternating
high pressure and mainly dry cold fronts moving through.
Wednesday through Thursday high pressure will slowly work its way
across the region. We should see mostly sunny skies during this
period and temperatures around or just a bit below normal. Highs
will range from the upper 60s to lower 70s with lows in the lower to
A cold front will approach Thursday evening and swing through on
Friday morning. The models are not in good agreement with how much
moisture will accompany this system. For now have opted to keep the
forecast dry, but some showers Friday morning are not completely out
of the question. Temperatures on Friday will be a bit cooler,
topping out in the mid to upper 60s.
Stout high pressure will build in once again for the weekend. With
it a much colder airmass will settle in as well. Model guidance
continues to trend lower with the temperatures this weekend and with
that the potential for frost grows. Saturday morning winds will
likely stay up a bit as the high pressure will still be to our
northwest. Lows will range from the upper 30s to lower 40s. Thus,
while there may be isolated some instances of frost in sheltered
areas, it is not expected to be widespread. For Sunday morning high
pressure will be right over the Ohio Valley with low temperatures
dropping into the 30s across the forecast area. Much of southern IN
and north central KY, excluding the metro areas, could dip into the
mid to lower 30s. Thus, have expanded the mention of patchy frost in
the grids. Some areas in the far northern Bluegrass may even dip to
around freezing. Highs through the weekend will be chilly as well,
topping out in the mid 50s to lower 60s. Temps will them begin to
moderate a bit by early next work week.
.AVIATION (06Z TAF Update)...
Issued at 104 AM EDT Tue Oct 13 2015
Main forecast concern will be fog/stratus beginning to plague sites
currently. KLEX has already gone IFR in stratus and expect KBWG to
go IFR mainly in fog soon. Will keep KSDF free of any restrictions,
but a brief IFR cig is not out of the question over the next couple
of hours. Otherwise, drier air will advect into the region through
the night, so expect KBWG and KLEX to improve to VFR over the next
few hours, possibly more towards sunrise at KLEX. Once conditions
return to VFR, the remainder of the day will feature westerly winds
possibly gusting to 20 knots at times, with sct/bkn VFR stratocu
developing mainly at KSDF and KLEX in the afternoon hours.