Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 241735
Area Forecast Discussion
National Weather Service Louisville KY
135 PM EDT Fri Mar 24 2017
Issued at 1200 PM EDT Fri Mar 24 2017
Although low clouds are still expected to develop this afternoon,
had to lift MaxT temps some given the fast rise we`ve seen so far
today. No other changes.
.Short Term...(This evening through Saturday night)
Issued at 315 AM EDT Fri Mar 24 2017
Southerly gradient has set up over the Ohio Valley ahead of a deep
closed low currently nearing the OK/TX Panhandle. Steady south winds
overnight are holding temps solidly in the 50s in most locations,
and min temps have likely already been realized.
Unseasonably mild conditions will persist today and tonight, with
south winds a bit on the breezy side and thickening cloud cover.
With the warm start and continued warm air advection, most locations
should be able to get into the 70s.
Tonight the upper low will parallel the old Route 66 corridor out of
Oklahoma into southern Missouri, and the warm conveyor belt will
slowly edge eastward across Kentucky and Indiana. Could see a few
showers working into southern Indiana just before dawn on Saturday.
Look for precip to gradually overspread the area through the day on
Saturday, with categorical POPs on Saturday night with the strongest
low-level jetting overhead. Thunder chances will ramp up, but severe
potential is limited due to lack of instability in a nearly moist
adiabatic profile. SPC Marginal Risk does nose into south-central
Kentucky, mainly south and west of the Natcher Parkway where timing
is more favorable for a few strong storms. Saturday night will be
mainly a soaking rain, as decent winds just off the deck should
remain aloft in a fairly stable environment.
.Long Term...(Sunday through Friday)
Issued at 300 AM EDT Fri Mar 24 2017
Upper pattern looks progressive through most of the week, with a
series of lows ejecting out of the Desert Southwest, and southeast
CONUS ridging to guide them ENE across the Ohio Valley. Therefore
expect mild but active weather to continue.
Pattern will be at its most amplified on Sunday, with a closed upper
low lifting NE from western Illinois into the Great Lakes. Main
southerly moisture surge will be to our east, but cyclonic curvature
in the flow and mid-level cold pool will support decent coverage of
showers. Best chances will be in the morning across the Bluegrass
region, where we are carrying likely POPs and tapering down to the
south and west.
Look for a brief break in the action Sunday night/Monday morning
before the next impulse swings through Monday afternoon and Monday
night. Decent instability with this system as CAPE cranks up to 1000-
1500 J/kg, and timing near the diurnal max will support a few strong
Beyond Monday forecast confidence is really limited by the
uncertainty of timing the parade of disturbances. And even where
shortwave ridging seems to be a good bet on Wednesday, models
disagree on where a decaying front will be. GFS hangs the boundary
up over the Ohio Valley while the ECMWF is more over the Tennessee
Valley. Will limit POPs for Wednesday and Thursday to the slight
chance range. Next bowling-ball upper low seems to be on track for
late in the week, but more likely will be beyond the 7-day forecast
at this time.
.Aviation...(18Z TAF Issuance)
Issued at 135 PM EDT Fri Mar 24 2017
Mostly clear skies late this morning and early this afternoon have
allowed for deeper mixing and gusts between 25-35 mph at times.
Given the onset of more cloud cover, expect gusts to be peaking now
and actually tailing off a bit this afternoon, so have kept mention
in TAFS around 25 to 30 mph.
Otherwise, expect a Few-Sct diurnal Cu and broken upper level
ceilings to move in later this afternoon and evening. Winds will
tail off to a SSE direction around 5 to 10 mph around sunset. With
LLJ cranking up after Midnight there is just enough speed and
directional shear coupled with an inversion to mention LLWS.
Inversion should break a couple hours after sunrise on Saturday,
with Bkn to Ovc mid level ceilings and low level moisture return
contributing to some Sct clouds around 4 K feet. Gusty SSW winds
should commence by mid to late morning. Rain chances should hold off
until just after this TAF cycle.