Scientific Forecaster Discussion
fxus63 ksgf 121053
Area forecast discussion
National Weather Service Springfield MO
453 am CST Thu Dec 12 2019
Short term...(today and friday)
issued at 245 am CST Thu Dec 12 2019
An upper level short level trough and surface low pressure will
move across the plains today. Gusty southerly winds will develop
across the area ahead of the low, with gusts around 30 mph
possible at times. Highs will warm into the lower to mid 50s this
afternoon, as afternoon humidities will generally fall into the
30 to 40 percent range. The gusty winds combined with the drier
air mass will result in an elevated fire weather risk across the
area this afternoon.
Not expecting any rain with this system due to the dry air mass in
place, just an increase in cloud cover. The clouds will increase
from west to east this morning then should start to clear from
west to east this afternoon. Lows will drop into the upper 20s
across south central Missouri to the middle 30s across
southeastern Kansas tonight.
Another trough will approach the area on Friday bringing an
increase in clouds during the day. Highs will warm into the lower
to middle 50s Friday afternoon. Winds will also not be as strong
on Friday as they will be today.
Long term...(friday night through wednesday)
issued at 245 am CST Thu Dec 12 2019
The upper level short wave trough will track across the region
Friday night into Saturday. As the trough moves across the area a
colder air mass will advect south into the area. Moisture will
again be limited but the lift with this system should be able to
overcome the dry air and result in some light rain or flurries
across the area. Not expecting much in amounts as just a trace is
generally expected due to the drier air, but some light
precipitation will be possible, especially across central Missouri
closer to the low and better lift.
Another upper level trough will move onto the West Coast Saturday
and dig south into the Southern Plains by Sunday, before tracking
across the region Monday into Tuesday.
A colder air mass will be in place across the area as highs on
Saturday warm only into the upper 30s to the middle 40s and lows
Saturday night fall into the lower to middle 20s.
As the upper level trough is digging into the Southern Plains,
energy will track across the area and could result in a narrow
band of precipitation developing across the area Saturday night
into Sunday morning. Given the colder temperatures that will be in
place this band will likely be all snow. The questions are where
will any band be able to setup and how much precipitation will
be able to develop as drier air will still be in place. If enough
lift can develop, there could be a narrow band of minor
accumulating snow, but outside this band little if any will
likely occur outside the band.
As the trough digs into the plains, moisture will start to advect
to the north into the area Sunday. Warmer temperatures will also
start to move back to the north. The model ensembles continue to
show quite the spread on just how far north the warmer air will
make it. A difference in the track of just 30 miles to the north
to south will make a big difference on precipitation types and
amounts for any given area.
All models show the warm nose making it into at least far
southern Missouri, with some as far north as the middle of the
forecast area, and there are solutions that take it all the way to
the north of the area. This will have big impacts on the
precipitation types and amounts, so uncertainty still remains.
All the models are showing the freezing line and warm nose
advecting north close to each other, which would indicate snow
to the north of the line and rain to the south, with a mix
possible in the middle. A dry slot will also move across the
region which could result in some drizzle/freezing drizzle
development, but all is dependent on the exact track. The warm
nose and sub freezing surface temperatures will push back to the
south Sunday night into Monday. The precipitation should move out
of the area by Monday evening.
The question remains with the exact track of the system as a
farther northern solution would bring more in the way of rain to
the area, with a more southerly solution more snow/wintry weather.
The track then impacts where the warmer/colder air will be, where
the dry slot will setup, and where the better lift will occur,
which will all impact the preciptiation types and amounts. Again,
just a little shift north or south with the track of this system
will greatly affect the types and amounts. Will continue to
message the uncertainty but also that there is the potential for
wintry weather somewhere across the region Sunday into Monday.
Colder conditions will continue into the middle of next week, as
lows in the teens and 20s occur Monday and Tuesday nights and
highs in the upper 30s into the lower 40s occur Tuesday with highs
in the low to middle 40s on Wednesday.
Aviation...(for the 12z tafs through 12z Friday morning)
issued at 452 am CST Thu Dec 12 2019
Surface low pressure is currently located across the plains which
will cause the pressure gradient to tighten across the area this
morning into this afternoon. As a result gusty southerly winds
will occur. The low will move off to the northeast this evening
allowing winds to weaken. VFR conditions are expected across the
area as mid to high level clouds stream across the area. Low level
wind shear will remain possible through the mid morning hours.