Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 291549
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
1149 AM EDT Sun Mar 29 2015
Issued at 1140 AM EDT Sun Mar 29 2015
Winds will pick up from the south southwest early this afternoon as
a sharp surface trough now across Illinois approaches. Skies will
quickly cloud over across southwest Indiana by mid afternoon, and by
late afternoon across locations southeast of the Ohio River. A few
hours of light showers are still expected to spread across southern
Indiana early this evening, and the rest of the Commonwealth
overnight. Skies will clear Monday morning from northwest to
southeast Monday morning.
.SHORT TERM (Now through Monday)...
Issued at 300 AM EDT Sun Mar 29 2015
Early This Morning...
Temperatures will mostly start out in the 20s this morning, although
a few eastern cool spots will be in the upper teens. At this point,
it doesn`t look like the LEX/FFT minimum temperature records will be
broken early this morning.
Surface high pressure center over the area now will quickly slide
southeast to the Carolina Coast by early afternoon today. Meanwhile,
a progressive upper ridge axis will slide southeast over the region
by this evening. This pattern will set the stage for a mostly dry
Sunday, before chances for showers increase ahead of a cold front
later in the afternoon and early evening along and north of I-64.
Skies will start out mostly sunny today with a steady south wind
between 10 and 15 mph, gusting up around 25 mph at times. Cloud
cover will increase, especially in the afternoon signaling the
approaching system. Before this occurs, a marked warm up will occur
with temperatures reaching the low and mid 50s in most spots. Upper
50s to around 60 are possible in our far SW.
One other note worth mentioning will be fire weather concern. Some
data suggests that dew points will be slow to recover across the
southeastern half of the CWA this afternoon as some drier air mixes
back down. This will yield minimum relative humidity values near
critical thresholds. Meanwhile, southerly winds will be between 10
to 15 mph with a few gusts up around 25 mph. A look at Raws sites in
our southeast show that minimum 10 hour fuel moistures did get down
around 8-9 percent yesterday so another day of drying will likely
get them around criteria. Overall, its a pretty marginal setup along
with a fairly short window this afternoon as upper clouds spill in.
So, will just mention in FWF and monitor.
Tonight - Monday...
Although showers are possible across southern Indiana and north
central Kentucky from mid afternoon through early evening, the bulk
of the rain will fall overnight where likely chances will be
mentioned for a tenth of an inch or two of rainfall. Conditions
should be dry by Monday morning with skies quickly clearing behind
the passing cold front and high pressure building back in. Won`t see
a big cool down from this frontal passage as airmass is from a
Pacific origin. In fact, highs on Monday will likely be a couple/few
degrees warmer than Sunday. Look for mainly upper 50s and low 60s.
.LONG TERM (Monday Night through Saturday)...
Issued at 255 AM EDT Sun Mar 29 2015
High pressure will start off over the Tennessee Valley Monday
evening. That high will shift east as a weak cool front drops into
the Midwest Tuesday. Models had been dry with this feature, but the
latest GFS is starting to show some light QPF across south central
KY and the new NAM has some light returns in our southeast Tuesday
night. Ongoing forecast has been dry, and some of the better
performing models for pops in this mid-range period continue to
argue this way, so will keep them dry for now.
Forecast models are coming into better agreement on the next system
to affect the region for the end of the work week. Our region should
be solidly in the warm sector Thursday, with breezy south winds
bringing temperatures well above normal. That heating combined with
increasing moisture over the region should lead to scattered to
numerous thunderstorms. The latest GFS then brings the front into
the region Thursday night, whereas the GEM/12Z Euro hang it up to
our northwest as another disturbance developing over the central
Plains slows it down. The somewhat zonal flow aloft would lean more
toward the slower solution, until that next disturbance comes in to
kick the front forward. The new Euro coming in generally agrees with
this scenario as well.
The 12Z European has that next system as a fairly vigorous one, with
a deepening surface low moving across the Midwest during the day
Friday. That said, the new Euro has backed off on this vigorous
solution. Still, this system would be one to watch given the
potential for strong dynamics if such a system were to pass nearby.
Regardless behind it, we should see a cool down likely back to below
normal again for Saturday.
.AVIATION (12Z TAF Update)...
Issued at 645 AM EDT Sun Mar 29 2015
Surface high pressure and upper level ridging will keep conditions
mostly clear and VFR for the first half of this forecast cycle,
before conditions deteriorate this evening and overnight ahead of a
Surface high pressure centered over the area now will scoot off to
the east through the day with SE winds gradually veering to SSW and
increasing in magnitude through the day. In fact, expect 10 to 15
mph SSW winds with gusts up around 25 mph at times this afternoon.
Upper clouds will also begin to overspread the area this afternoon,
with bkn VFR ceilings beginning early this evening at SDF/LEX. Rain
showers are then expected between 8 and 10 PM EDT at SDF/LEX and
around Midnight EDT at BWG with some periods in MVFR in vis/cigs
possible. Cold front passes overnight with veering winds to WNW and
some lingering stratocu that could flirt with MVFR thresholds.