Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Louisville Kentucky
318 PM EST Wednesday Feb 10 2016
Short term (now through Thursday night)...
issued at 315 PM EST Wed Feb 10 2016
Guidance calling for snows over eastern MO to graze our southwest
forecast area before they dissipate, as the upper-level system
generating them moves into increasingly drier air aloft. This
balancing act will mean a continued lower chance for measurable
liquid equivalent snowfall, though the dry nature of the snow will
mean a chance for up to a few tenths of an inch of new snowfall to
drop across south central Kentucky by daybreak Thursday.
High pressure will build into the Midwest the rest of the day
Thursday, bringing some sunshine to the region. Our southern zones
will take a little longer for the clouds to scatter out. After lows
in the teens tonight, maybe even single digits in our cold spots in
the northeast, we should get a little warmer for highs tomorrow
compared to today. Still our northeast may only see the mid 20s,
whereas south central Kentucky should get into the lower 30s.
The high will shift east of the region Thursday night, with another
clipper system projected to be approaching the region by daybreak
Friday. Increasing clouds may lead to our lows being more in the
evening and then slowly increase or remain steady the rest
of the overnight.
Long term (friday through wednesday)...
issued at 315 PM EST Wed Feb 10 2016
Models are calling for that clipper system to have the most impact
on the northern half of our forecast area. However, the Euro came in
drier, instead shooting for our southeast forecast area to fire up
with some snow showers in the afternoon. Either way, this system
will not have much moisture to work with here, so totals should stay
under an inch. The Arctic high pressure behind this system will
bring temperatures back down after a "warm" day Friday in the 30s.
Expect highs Saturday to top out in the 20s, some 20 degrees below
normal for mid February. High pressure moving over the region
Saturday night should make for calm conditions and lows in the
single digits to low teens.
That high will shift to our east during the day Sunday, making way
for the next system to impact our area. The GFS/Gem each have a
quicker hitting system, with precip beginning Sunday night. The Euro
is coming in consistent with its previous run of a little later
onset followed by a wide deformation band moving across our area.
This solution would bring quite a bit of snow. To decide which way
to lean, looked at verification stats over the last 6 months for
most reliable pops and found the consall and MOS as well as the GFS
have been the better ones to choose from. So will lean the forecast
that way for now. The consensus will include some info from the
Euro, so the trend will be snow-ier, though still way too early to
Temperature forecasts will depend greatly on how far north the
associated surface low gets, but for now guidance seems a bit high.
Will go under guidance here as well as the next day, assuming we
have some snow cover on the ground. Models are trying to bring in a
sudden warmup after this Monday system, and think that snow cover
could slow it down a bit. As for precip, some guidance is keeping
light quantitative precipitation forecast in the northwest flow behind the Monday system.
Aviation (18z taf update)...
updated at 1130 am EST Wed Feb 10 2016
Scattered snow showers will linger through mid afternoon. Areal
coverage has already diminished since this morning, and will
continue to do so this afternoon. Despite VFR prevailing conditions,
ceilings can still dip into mvr category at times, and vsbys could
actually drop into IFR briefly with some of the heavier snow
showers, especailly at Lex.
The snow showers should dissipate with the setting sun.
Westerly winds of 8-12 kts will decrease this evening.