Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 081714
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
1214 PM EST Sat Mar 8 2014
...Updated Aviation Discussion...
Issued at 915 AM EST Sat Mar 8 2014
Forecast looks mainly on track this morning, and only made minor
adjustments to temps/winds/dewpoints over the next few hours. Have
continued to monitor a decent area of rain (even an embedded rumble
of thunder) across portions of SW MO associated with an area of
isentropic ascent out ahead of the approaching synoptic shortwave.
The latest 12Z NAM has no handle on this convection, thus its
solution will largely be discounted. The GFS/HRRR have a better
handle on this area of precip, weakening it as it crosses into
southern IN and northern KY late this afternoon. Will continue to
monitor trends over the next few hours, and make any adjustments to
pops as necessary.
.SHORT TERM (Now through Sunday)...
Issued at 245 AM EST Sat Mar 8 2014
Clouds will continue to increase and bases will lower throughout the
day. Light to calm winds early this morning will increase out of the
southwest to around 10 mph or so by this afternoon, as a weak
surface cold front approaches from the west. Temperatures are
expected to warm into the upper 50s to lower 60s this afternoon. The
bust potential here will depend on total cloud cover.
The cold front is on schedule to push through the region late this
afternoon and through the evening hours, with light rain trailing
the front. QPF amounts remain very light and the latest guidance
suggests that not everyone will see rain tonight, so kept PoPs
around 40 percent. Winds will become northwesterly behind the front,
with speeds of 5-10 mph for the overnight hours.
Some cold air will filter into the area tonight as the rain departs
and skies begin to clear. Expect temperatures to range from middle
20s across our far northern Indiana counties to middle and upper 30s
across south-central Kentucky by daybreak Sunday. Temperatures will
be a little cooler Sunday, with afternoon highs ranging from upper
40s to middle 50s. Skies will be mostly sunny with light winds.
.LONG TERM (Sunday night through Friday)...
Issued at 255 AM EST Sat Mar 8 2014
Current large trough over the Central Plains looks to stretch out,
with a weak vortmax having just passed us and heading southeast
Sunday night and the main part of the trough hanging back over the
Red River Valley. The 00Z GFS indicate a couple of low centers
forming out of the latter feature, but neither looks to bring precip
into our region through Tuesday.
A northern stream system looks to change that dry pattern Tuesday
night. Whether it phases with the southern stream is still up for
debate in the models, but some kind of frontal passage is looking
more likely. A look at cross sections, indicates a brief surge in
moisture, which should be enough to take advantage of the lift with
this front to produce some rains. AllBlend pops are high-end chance
to likely range, not too far off previous forecast.
Once that front clears us, we look to cool off and dry out again for
the end of the work week. Temperatures at the start of the period
and ahead of that front will be above normal, then will fall to a
below normal for the rest.
.AVIATION (18Z TAF Update)...
Updated at 1212 PM EST Sat Mar 8 2014
High clouds continue to stream by early this afternoon in advance of
a cold front. The cold front currently stretches from central IN
southwest into southern IL and southeast MO. Behind this front,
some light precipitation has persisted across portions of southern
MO. There remains some uncertainty as to how much precipitation
will make it into the terminals this evening into tonight, as the
current area is rapidly weakening as it encounters a drier airmass
over the Ohio Valley. Overall, guidance has trended drier, thus
will continue with only VCSH wording at KSDF and KLEX.
Precipitation looks less likely to impact KBWG, thus will keep all
precip mention out at this time. Behind the front, ceilings will
drop to MVFR thresholds for a time overnight, before quickly
returning to VFR by Sunday morning.
Winds will be out of the southwest at 8-12 knots today, before
switching to NNW around 6-10 knots tonight as the front pushes
through. Winds will go light and variable by Sunday morning as high
pressure builds into the region.