Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Louisville Kentucky
341 am EDT sun Mar 9 2014
Short term (now through monday)...
issued at 330 am EDT sun Mar 9 2014
Surface high pressure and associated cooler air continues to build
into the Ohio Valley, behind our departed front. Clouds will clear
from west to east today, with mostly sunny skies expected by this
afternoon. Temperatures starting out in the upper 20s and 30s around
dawn will warm into the low and middle 50s, which is about normal
for this time of year. Northerly winds this morning will become
light and variable through the day.
Surface high pressure will quickly move east with winds becoming
southwesterly by tonight. An area of low pressure will move across
the northern Great Lakes, which will enhance the pressure gradient
over the Ohio Valley. This slight increase in southwesterly winds
will help keep the boundary layer mixed, particularly after
midnight. Lows in the middle and upper 30s are expected.
Southwest winds will continue Monday and be a bit breezy by the
afternoon. A few clouds around in the afternoon will not limit our
warming trend, as we reach the low to middle 60s for highs.
Long term (monday night through saturday)...
issued at 330 am EDT sun Mar 9 2014
A closed low is represented well in the various deterministic and
ensemble solutions Monday night over Texas, with a more zonal flow
over our region. By Tuesday evening, this low will shift to the
la/MS coast. At the same time another northern stream system will be
dropping southeast across the Central Plains. This latter system
will spawn a surface reaction, with low pressure forming along a
cold front stretching from Texas to central Indiana.
This low looks to cross Kentucky some time early Wednesday, as a
relatively deep system. Thus we can expect breezy conditions as well
as a good shot at rain. Cannot rule out an elevated thunderstorm
closer to the low track, so have added in slight chances for thunder
Tuesday night. The 12z Euro kept in some rain chances well into the
day Wednesday, as a second surge of upper level energy drops down
from the Great Lakes. Will continue to limit precip chances
Wednesday night to the slight range, given the well-documented
frozen nature of the lakes. Think the Gem and 12z Euro are pulling
too much moisture out of the lakes, based on their quantitative precipitation forecast forecast
Rest of the period should be quiet, precip-wise. Latest GFS tries to
bring a front with a thin band of precip in here Saturday, but think
ridging across the southeast U.S. Should block any significant
moisture from getting in here, so will go with a dry forecast.
Temperatures will start off pretty warm ahead of Tuesday night's
front. Readings may touch the 70-degree mark for a few spots in the
afternoon. Then with the frontal passage, readings will drop through
the day Wednesday. A warmup should return for Friday and Saturday,
with again getting to the upper 50s/low 60s.
Aviation (06z taf update)...
updated at 1230 am EST sun Mar 9 2014
The front is well east of all taf sites at this time. A few showers
around bwg will continue to slide south and east. Dewpoints are slow
to drop, so visibilities and ceilings will remain MVFR through a
good portion of the early morning hours. Will lean toward the lamp
probs and improve conditions to VFR shortly after daybreak, but will
continue to monitor trends this morning. Northerly winds will weaken
as high pressure continues to build across the region and become
light southwesterly later this afternoon as the high moves east.