Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Springfield MO
1148 am CST sun Dec 8 2013
..update to aviation section...
issued at 1148 am CST sun Dec 8 2013
Forecast remains on track as areas of freezing drizzle persist
across the area. As mentioned in the prior update, infrared satellite
imagery continues to indicate colder cloud tops moving
into/developing over the area. This may provide enough seeding for
a mix/switch over to light snow from time to time.
The good news is that radar echoes have been on the decrease and
improving conditions continue to move in from the west. Will go
ahead and keep the advisory going and if conditions show faster
improvement, a cancellation of the advisory will be warranted.
Update issued at 1028 am CST sun Dec 8 2013
Forecast updated to expand the Winter Weather Advisory to the
remainder of our outlook area and extend the advisory in time
through 3 PM.
First round of freezing drizzle is now making its way out of
southwestern Missouri and into central Missouri. Visibility has
improved over the past hour or two at ksgf and a few surrounding
locations (albeit for the moment) and visibility has begun to
decrease at places like ktbn and kvih where freezing drizzle is
now being reported. Another batch of freezing drizzle is now
entering extreme southeastern Kansas and far western Missouri. A
call from kdot and area observations indicate that this activity
is a mix of predominately freezing drizzle and some light snow.
Precip type today will continue to oscillate a bit. Infrared satellite
imagery does indicate cloud tops starting to get near or below the
-10c level, which coincides with more frequent reports of -sn in
OK and Kansas. As a result, have kept a mention of light snow showers
into this afternoon for most locations...though freezing drizzle
will likely be the predominate precip type.
Accumulations, as you would expect, will not be eye popping by any
measure. A trace to a few hundredths of an inch of ice accumulation
and a dusting of snow is expected. The main issues continue to be
temperatures in the upper teens/lower 20s, subfreezing surfaces
and existing snow cover. This will continue to make for slick
roads across the area through the rest of today.
Weak lift in the low levels responsible for this drizzle/light
snow should shunt to the north and east later this afternoon and
evening. Have held on to a mention of patchy freezing drizzle from
the plateau into central Missouri into the mid evening hours,
however we do believe that most drizzle will occur from now
through the mid afternoon hours.
Short term...(today and tonight)
After a brief round of snow last night, the lower troposphere had
a difficult time saturating. Nearly all models were suggesting
freezing drizzle by now, however, surface dew point depressions at
9z were still around 10 degrees.
We think saturation will eventually occur in some spots today.
Therefore we kept the freezing drizzle in the forecast, but kept
probability of precipitation in check.
A dry slot was moving in from the southwest, as seen on water
vapor. This feature will completely eliminate cloud ice.
Therefore, the main precipitation type will be freezing drizzle.
Many areas today will remain dry.
A cold front will shift across the region later tonight. This will
bring in drier and cooler air. Overnight lows should fall back
into the teens.
Long term...(monday through saturday)
We could experience some very minor snow accumulations Monday
night as a weak disturbance approaches from the west. Moisture
will be limited, therefore, only a dusting to maybe an inch is
expected. This snow will quickly shift east of the region,
allowing for dry conditions on Tuesday.
The overall upper level pattern will evolve back into a split flow
regime by mid week. The northern stream will influence the Ozarks
weather more than the southern stream, bringing chilly and dry
conditions through much of the week.
Temperatures in the 20s and 30s will be common, meanwhile,
overnight lows in the teens are expected on a nightly basis.
By Saturday morning, there are signals that would suggest light
snow possibilities as a weak disturbance approaches from the west.
At this time we'll carry a mention of this in the forecast and
hazardous weather outlook.
Otherwise it doesn't appear as though anything too significant is
in the offing over the next 7 days. Have a great Sunday.
Aviation...(for the 18z tafs through 18z Monday afternoon)
issued at 1148 am CST sun Dec 8 2013
Numerous hazards to discuss for area aviation interests. IFR
ceilings remain widespread across the area and this will continue
for several more hours. Only exception is at jln where modest
improvement to low end MVFR ceilings are likely. Areas of drizzle
and scattered light snow showers continue across the region at
this hour. This will result in variable visibility early this
afternoon, ranging from VFR to MVFR for the most part. This
precipitation is expected to end by late this afternoon. After
brief improvement late this afternoon, widespread MVFR
visibility and IFR ceilings are expected this evening through
tonight with gradual improvement Monday morning as a cold front
moves through the area.
MO...Winter Weather Advisory until 3 PM CST this afternoon for
Kansas...Winter Weather Advisory until 3 PM CST this afternoon for ksz073-