Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Springfield MO
259 am CST Fri Dec 20 2013
Short term...(today through sunday)
issued at 259 am CST Friday Dec 20 2013
It's shaping up to be a very active next few days across
southeastern Kansas and the Missouri Ozarks, as a strong storm
system affects much of the nation's midsection. Starting out this
morning, a strong cold front is dropping south across the Midwest,
and will begin to move into the County Warning Area this morning.
The initial concern this morning will be with the potential for
drizzle/freezing drizzle as this front moves into the area.
Regional radar and surface observations have shown some light precip
to our north this morning, and will continue with a mention for
freezing drizzle in the far northwestern corner of the County Warning Area this
morning, where temperatures should fall, and then likely remain,
below freezing after daybreak. The occurrence of this freezing
drizzle as well as sensible impacts from it remain a somewhat
low-confidence proposition, so will hold off an any sort of short
term advisory for now. Trends will be monitored across the
northwestern County Warning Area through the morning, however.
Otherwise, some "regular" drizzle and perhaps a few light rain
showers will be possible along and behind the front today.
Obviously, there will be a considerable range in high temps today,
with much of south central Missouri warming into the low to mid 60s
once again. Once the front reaches a given location, temperatures
can be expected to fall for the remainder of the day.
By tonight, the front should stall out along just south of the
forecast area. Precipitation will begin to increase overnight from
the south, and should really expand in coverage around daybreak
tomorrow morning. By daybreak tomorrow, temperatures should be at
or just below freezing along and north of I-44, resulting in the
threat for freezing rain late tonight and Saturday for areas along
and north of the Interstate. The good news, in terms of ice
accumulation, is that temperatures should gradually rise to or just
above the freezing mark on Saturday, helping to reduce the impacts
from the freezing rain to some degree. Current forecast ice amounts
range from a glaze to a few hundredths along the I-44 corridor, to
two tenths to a quarter inch north of U.S. 54. Of course, given the
fact that this will be dependent on just a degree or two difference
in temperature, ice amounts will certainly be fine tuned over the
next 24+ hours.
For areas south of I-44, heavy rain remains the primary concern,
with rainfall amounts of 2-3", with locally higher amounts,
expected. South central Missouri, east of a line from Bull Shoals
Lake to Salem, continues to appear most likely to see the heaviest
rainfall amounts. Given the fact that ground across this area is
already saturated due to recent significant snow melt, flooding of
low water crossings, creeks, streams, and rivers is likely this
By Saturday evening, a well-developed dry slot should punch into the
southern County Warning Area as the main upper trough begins to swing through. At
the same time, the northern portions of the County Warning Area will likely get
clipped with the deformation zone/trowal, bringing a quick shot of
accumulating snow. Think that as much as 2-5" will be possible
north of a Columbus, Kansas to Osage Beach line, with a fairly sharp
gradient in accumulations expected. Differences in accumulation of
2-3" across a single County will be common. Between the
aforementioned Columbus to Osage Beach line and I-44, a dusting to
an inch of snow is expected. Snow should be waning by daybreak
Sunday, and end by mid day.
The current Winter Storm Watch and Flood Watch will largely remain
unchanged for now, with the exception of adding Miller County, MO and
Cherokee County, Kansas to the Winter Storm Watch. Given the fact that
significant winter weather is still more than 24 hours out, and
continued uncertainty regarding the exact location of the freezing
line, thought that it was prudent to hold onto the watch until the
day shift had a chance to digest the 12z suite of model guidance.
Long term...(sunday night through thursday)
issued at 259 am CST Friday Dec 20 2013
A quieter and seasonably cold pattern will settle across the
region much of next week. Overall, temperatures will be at or
below average with not much in the way of precipitation expected.
Five wave charts keep the door open to the occasional cold front,
the first of which will accelerate through the region on Christmas
day. As is typical of a clipper type system, moisture will be
sparse and light rain Wednesday afternoon will change to light
snow Wednesday night. Lack of moisture and the speed of the system
will be prohibitive to accumulation and have kept a few tenths of
snow going for the time being. The next front is slated to move
through the region toward the end of next week, though there is a
decent amount of model spread at this time.
Aviation...(for the 06z tafs through 06z Friday night)
issued at 1101 PM CST Thursday Dec 19 2013
Ceilings have lifted and thinned out a bit this evening as a weak
shortwave trough exits the region. However...infrared satellite
shows increasing clouds to our southwest as another disturbance
embedded in southwest flow aloft moves toward the region. So will
lag the onset of MVFR ceilings for a few more hours but expect by
09z to 11z that most sites will have at least MVFR ceilings and
maybe some light drizzle.
The cold front to our north has made some progress southward this
evening and currently is making its way across Kansas City.
Surface winds north of the front have become more perpendicular to
the front so expect some decent southward progress over the next
several hours...with a passage at Joplin around 11z...Springfield
around 12z. The front is expected to stall out near Branson later
today so for now will give them a west wind by around 17z.
Later tonight...will bring in predominant light to moderate rain
after 02z as a stronger shortwave currently over West Texas moves
over the area. Locations to the north of our airports could see a
wintry mix with this batch and we will have to watch temperature
trends closely to see if colder air seeps further south than expected.
MO...Flood Watch from this evening through Saturday evening for
Winter Storm Watch from late tonight through late Saturday night
Kansas...Winter Storm Watch from late tonight through late Saturday night