Area Forecast Discussion
Issued by NWS Springfield, MO
FXUS63 KSGF 061744 AAA
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1144 AM CST Fri Dec 6 2013
...Update to Aviation Section...
Issued at 1144 AM CST FRI DEC 6 2013
Snow to taper off this afternoon.
Upper wave overhead is trekking to the east. Water Vapor imagery
showing a well defined dry slot punching through the southern
Plains and enveloping much of Oklahoma. Over the past hour, a
"back edge" to radar reflectivity values is becoming more well
defined. Surface observations coincident and just to the west of
the back edge of the radar reflectivities still indicate sporadic
-SN reports with steadily increasing visibility. Bottom line, the
light at the end of the tunnel is close at hand.
Assuming the current trends continue, the back edge of the
accumulating snow will head east at 25 mph. This will reach
Springfield around/just after 130 PM, the Branson area around 230
PM and the eastern Ozarks after 430 PM.
No changes to the updated snow forecast are needed at this time
and will let them ride.
Will slow play ending advisories/warnings, especially any warnings
areas, due to continued travel impacts of blowing snow given a
10-15mph northerly wind.
In addition, we will be closing monitoring the need for a wind
chill advisory for the area tonight as the brunt of this cold
airmass filters into the region.
UPDATE Issued at 1031 AM CST FRI DEC 6 2013
Substantial update to the forecast to account for latest trends.
Main upper wave has moved into the Midwest producing another large
area of snow across the region. Bands of moderate snow are
embedded within this large area of snow, producing consistent
hourly snowfall rates on the order of one half inch (nearing one
inch beneath the bands of moderate snow). Deep lift over the area
is being aided by the right entrance region of a strong upper
level jet. Models do indicate "splotchy" areas of higher omegas,
which makes sense given the embedded heavier bands of snow we are
With a very cold air mass in place, this snow is light and fluffy
with snow to liquid ratios easily between 15:1 and 20:1...which
is somewhat unusual for us to observe. As a result, have upped
snowfall amounts for today, especially in areas along and
southeast of the I-44 corridor. For the advisory area, amounts of
a dusting to 2 inches are expected. Across the warning area, an
additional 2 to 6 inches is expected today. From a storm total
perspective, snow amounts will vary considerably across the area.
The least amounts will continue to be across portions of extreme
southeastern Kansas, west central and central Missouri, where a
dusting to less than an inch has been observed so far. The
heaviest band of snow looks to be across southern and south
central Missouri (generally along and southeast of the I-44
corridor) where a widespread 6 to 10 inches of snow is expected.
There will be a band of higher snow totals, around 12 inches, along
and either side of a line from Cassville/Nixa/Ava/Houston/Round
Given the banded nature of this snow, and the very high snow to
liquid ratios, locally higher amounts are certainly plausible just
about anywhere in the warning area.
.SHORT TERM...(Today and Saturday)
Round 1 of this winter storm produced an axis of 4 to 6 inches of
snow, roughly along a line from Pineville to Houston Missouri.
Officially here at the Springfield office, we measured 4 inches.
Amounts were much lower in south central Missouri, due to heavy sleet
present. Through midnight, West Plains and Eminence had measured
2 inches, while Alton only had 1 inch of sleet accumulation. Alton
also had about 1/8th of an inch of freezing rain accretion.
Further north, a sharp cut off in accumulation had occurred.
Bolivar only had a dusting, and Pleasant Hope had about an inch.
Therefore, locations north of the Interstate had so far missed out
on the bulk of this winter storm.
Round 2 begins this morning, as an upper level speed max
approaches from the southwest.
The primary precipitation type will be snow for all locations,
since the depth of the arctic air continues to increase. Despite
ratios of around 15:1, a massively dry air mass will cut into
Dew point depressions ranging from 10 to 15 degrees were measured
from Lake of the Ozarks, down to PITTSBURG Kansas. This dry air
should really work over accumulation amounts, therefore, we kept a
conservative forecast going through the remainder of this event.
This dry air will have less impact on south central Missouri,
where more snow accumulation is expected today. We now have an
overall storm total accumulation of 6 to 8 inches for areas along
and south of a line from Anderson, to Marshfield, and to Salem. We
very well could see an isolated 9 inch amount somewhere near
Houston or Willow Springs.
For locations along Interstate 44 from Springfield to Rolla,
amounts will range from 4 to 6 inches. Therefore we`re only
expecting another inch or two for the Springfield metro area.
Again that is mainly due to dry air cutting into amounts.
Snow will taper from west to east late this morning and into the
afternoon hours, setting the stage for a bitterly cold night. Look
for overnight lows to fall into the lower single digits. Areas
with heavier snow pack could experience sub zero temperatures
early Saturday morning. A Wind Chill Advisory may be needed for
Saturday morning. I will pass this decision off to the day shift
so they can evaluate the latest guidance with temps and winds.
Saturday will be dry and cold, with highs only warming into the
teens to around 20 degrees.
.LONG TERM...(Sunday through Thursday)
Another round of light snow is possible Sunday. This upper wave
will have much less moisture available, and accumulations could be
on the light side. For now I`ll let the ongoing forecast ride, but
amounts will probably need to be lowered.
Another blast of cold air will spread in Monday night, causing
temperatures to fall below zero in many locations early Tuesday
Dry and chilly weather can be expected through the remainder of
next work week. Fast northwest flow will suppress Gulf moisture
well south of the region.
There may be a pattern change toward the Friday and Saturday
period. Both the GFS and the Euro show a brief period of southwest
flow evolving, along with an approaching wave. This could give us
a quick shot of precipitation toward next weekend.
Otherwise, the extended forecast is looking uneventful at the
.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 1127 AM CST FRI DEC 6 2013
The winter storm moving across the region will continue to impact
flight conditions through 00z. While the snow will taper of this
afternoon, MVFR ceilings are expected along with blowing snow.
The blowing snow will reduce surface visibilities to MVFR. High
pressure building into the region this evening will allow for
clearing skies during the overnight hours with VFR flight
conditions expected into Saturday morning. A few cold weather
cumulus will be possible through the day on Saturday but will have
no impact to aviation concerns.
MO...WINTER STORM WARNING until 6 PM CST this evening FOR MOZ082-083-
WINTER WEATHER ADVISORY until 6 PM CST this evening FOR
KS...WINTER WEATHER ADVISORY until 6 PM CST this evening FOR KSZ073-