Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 020027
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
827 PM EDT Mon Jun 1 2015
Updated 827 PM EDT Mon Jun 1 2015
Echoes on regional radars have nearly dried up, which is supported
by model data that keep things pretty dry overnight, so went ahead
and reduced PoPs to scattered sprinkles. No other changes.
.SHORT TERM (Now through Tuesday Night)...
Issued at 235 PM EDT Mon Jun 1 2015
Latest water vapor imagery overlaid with 500 mb heights shows an
upper level shortwave trough across western TN slowly moving
east/northeast. At the surface, a weak area of low pressure lies
across southwest Virginia which has brought low clouds, showers and
north/northeast winds to the region. Mid afternoon readings were in
the upper 50s to middle 60s, or closer to normal lows for June 1st.
Overall, an unseasonably cool start to meteorological summer across
the lower Ohio Valley.
For this evening, plan on most of the shower activity to subside or
lift off to the north/east giving way to just cloudy skies and a
slight chance of sprinkles or light rain showers. Model soundings
show some weak mid level drying and subsidence, so expecting
precipitation coverage to be more isolated. Some light patchy fog
may develop in some of the favored sheltered and valley locations
given the ample low-level moisture and today`s rainfall. Finally,
plan on lows in the mid 50s to around 60.
The mid/upper level shortwave closes off along the KY/TN border
tomorrow and will provide another cloudy and seasonably cool day to
the region. Saturation is not as deep and there is less forcing
compared to today, so expecting a mainly dry day. After starting the
day solidly in the clouds, some afternoon breaks are possible,
especially across southern Indiana and northern Kentucky. Plan on
highs in the low to mid 70s. Continued cool with just a slight
chance of showers across the south for tomorrow night as lows fall
into the mid 50s to around 60 again.
.LONG TERM (Wednesday through Monday)...
Issued at 300 PM EDT Mon Jun 1 2015
Upper low over eastern KY/TN will still exert its influence through
the early portion of the extended, taking at least a day or two just
to retreat to the Carolina coast. We`ll be mostly on the drier side
of this circulation, but with just enough of a lingering cold pool
aloft to at least support chance POPs each afternoon/evening from
the Bluegrass region south to around Lake Cumberland, but tapering
down to slight chance near the I-65 corridor and dry farther west.
In reality, the cutoff between POPs and no POPs will likely be
sharper than that, but with limited confidence in the placement of
that gradient, will take a more broadbrush approach.
Friday will be the warmest and probably driest day as a ridge builds
from the southwest. However, this will be short-lived as a NW flow
disturbance dives toward the Ohio Valley on Friday night. With
decent model agreement, will break the otherwise diurnal pattern and
bring solid chance POPs into the north. Over the weekend the front
will hang up and wash out somewhere over the Ohio/Tennessee Valleys,
and with NW flow aloft that could turn into an unsettled pattern.
Will keep POPs on the low side as the model solutions start to
diverge. Temps near climo by day, and a bit above normal by night
given plenty of cloud cover.
.AVIATION (00Z TAF Update)...
Updated 725 PM EDT Mon Jun 1 2015
A stubborn upper low will drift only about 270 miles from west
Tennessee to east Tennessee during this TAF period. Mid- and
upper-level moisture will move out early this evening, but low level
RH will remain trapped under an inversion tonight into Tuesday
morning. Ceilings will be low, probably IFR during the overnight
hours. Some light fog will be possible as well, especially at LEX
where appreciable rain fell earlier today, though a northeast breeze
will help to keep vsbys at least MVFR.
Ceilings will slowly lift tomorrow. SDF stands the best chance at
losing sub-VFR cigs first as dry air filters in.