Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 170513
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
113 AM EDT Thu Apr 17 2014
...Updated Aviation Discussion...
Issued at 1010 PM EDT Wed Apr 16 2014
Areas of frost still look possible east of I-65 tonight.
Temperatures in this area are already in the 42-46 degree range and
expect them to fall into the mid to upper 30s after midnight. With
dewpts slowly rising throughout the night, low level moisture will
probably be sufficient for frost formation. However, sfc winds look
like they might stay up a bit possibly limiting frost formation.
Not confident in frost formation but don`t have enough evidence to
remove the advy so will continue it through 13Z.
.SHORT TERM (Now through Thursday Night)...
Issued at 300 PM EDT Wed Apr 16 2014
Quiet weather in store for this period, with a low pressure trekking
slowly across the upper Midwest and a dry airmass in place ahead of
it. The flow aloft will be more moist, allowing for increasing
clouds there, but no precip is forecast in this period, save for the
very end of the period across my western counties.
The only concern will be for frost potential tonight. It continues
to look like our western areas will stay warmer, with slightly
stronger southeast winds and a thin band of thicker cirrus moving in
from the west. The lows I have east of the I-65 corridor are in the
mid 30s. RH values are on the border for frost production, but will
leave frost advisory as is, in case temperatures drop further than
what I have.
.LONG TERM (Friday through Wednesday)...
Issued at 245 PM EDT Wed Apr 16 2014
The latest time-height analyses of heights, 850 hPa temperatures,
and 1000-500 hPa thicknesses continue to indicate a warming trend
through the long-term period. There will be two frontal passages,
but these are minor with no major hazardous weather expected.
The first frontal passage will occur Friday, with northern stream
and southern stream systems trying to phase over our area. Latest
guidance indicates some light rain showers are possible, but perhaps
not everywhere given the systems will likely not phase. Have trimmed
PoPs back a bit. Temperatures in the 60s will be common for highs
Friday, with temperatures dropping back into the 40s Friday night.
The weekend looks nice if you like temperatures in the 60s and 70s
under mostly sunny skies and light winds. Clouds will increase
through the day Sunday as our next weather system approaches from
A progressive system will bring our next round of rain and perhaps a
rumble of thunder to the Ohio Valley around Monday. There remain
some model timing differences with Sunday night through Tuesday
being the window. So, confidence in overall timing remains a bit
low, but even very long-range guidance from last month was pegging a
system moving through here around the 21st. Will continue the chance
of showers and isolated thunderstorms centered on Monday. We dry out
Tuesday through Wednesday and continue our warming trend.
Temperatures should top out in the upper 60s and lower 70s Monday
and warm into the lower and middle 70s by Wednesday.
.AVIATION (06Z TAF Update)...
Issued at 110 AM EDT Thu Apr 17 2014
High pressure ridge axis is currently centered along the eastern
coastline of the US this morning. The ridge axis should continue to
move off to the east throughout the period resulting in a more south
to southwesterly flow developing across the Ohio Valley later this
morning. For the remainder of the overnight period, the forecast is
simply an extension of the previous one. Band of mid-high level
cirrus will continue to march eastward across the terminals
overnight resulting in BKN250 conditions. Winds are expected to
remain light and variable at KSDF and KBWG...with a light easterly
to east-southeasterly component over at KLEX. High clouds are
likely to scatter out later this morning...though VFR are expected
throughout the day. Surface winds will pick up more from the south
to southwest throughout the day with speeds of 8-10kt.
KY...FROST ADVISORY until 9 AM EDT /8 AM CDT/ this morning FOR