Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO
FXUS63 KEAX 170356
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
956 PM CST Mon Dec 16 2013
Issued at 953 PM CST MON DEC 16 2013
Frontal boundary which was stalled over northern MO this afternoon
surged southward late in the afternoon and has now pushed into
southern MO. Temperatures which initially plummeted 15-20 degrees
after passage stabilized after the initial fall. Increasing mid
clouds associated with warm air advection aloft and a strung
vorticity lobe streaking through SD/NE/IA tonight could generate some
flurries across the far north central/northeastern counties.
Temperatures over these areas have also seen their overnight lows as
the cloud cover and warmer temperatures spread southeastward.
Except for some patchy dense freezing fog in and around Boonville the
fog has been slow to develop. So, have backed off on fog development.
.SHORT TERM...(This Evening through Tuesday)
Issued at 303 PM CST MON DEC 16 2013
Amazing thermal gradient across the CWA this afternoon, with slow
stratus burn and snow cover keeping temperatures in the mid 20s
across northeast Missouri. On the other side of the stalled Chinook
warm front, readings have soared into the middle and upper 50s from
Kansas City into the Lakes regions. In between, some interesting
microscale sloshing has been going on along a weak boundary, making
hourly forecasting a real challenge (STJ, for example, rose to 46 and
then had a north wind shift and fell to 38).
For tonight, winds will once again stagnate ahead of a weak NW flow
impulse that will pass well north of the region. A trailing surface
boundary will induce an increase in west/northwest winds after 3AM.
However, in the interim period this evening, temperatures will
likely fall quickly under fairly optimal radiational cooling setup.
SREF probabilities indicate a moderate-high likelihood that fog may
once again redevelop later this evening. This would likely occur
first across the colder airmass over NE MO, with conditions becoming
less certain back toward I-29 and the MO river.
.LONG TERM...(Tuesday Night through Monday)
Issued at 303 PM CST MON DEC 16 2013
Tuesday: Tricky temperature forecast again on Tuesday as a weak
surface trough passes through the area early in the morning. Weak
cold air advection aloft and a light northwesterly wind should keep
the upwards temperature swing in check, but could still see areas of
the southwestern CWA in the upper 40s to near 50. In the northeast,
the lack of snow melt today will again influence the temperatures on
Tuesday and we could see another day with readings struggling to
reach the freezing mark in Kirksville.
Wednesday-Thursday: Confidence growing on the potential for the
area to climb into the 60s on Wednesday and Thursday ahead of a
frontal boundary approaching the region Thursday night. Very warm
low level temperatures will advect into the region by Wednesday with
an increasing surface pressure gradient leading to breezy
southwesterly winds. 900:800 mb temperatures some +10C to +12C
would suggest rapid warming into the 50s and even 60s in the
southwestern CWA. Breezy southwest winds will continue overnight as
a 50+ knot LLJ develops across the Plains. These strong low level
winds should promote mixing throughout the night, not only keeping
temperatures well above normal, but pushing moisture into the area.
Stratus and even fog may develop over the colder grounds of northern
The frontal boundary will approach the region late on Thursday, slow
enough to allow daytime highs to again break the 50s and even 60s.
The most prevalent atmospheric moisture remains in the lowest 300 MB
of the sounding which would suggest the potential for drizzle/fog
over the northeastern third of the CWA. Regarding temperatures, CIPS
analogs for Thursday suggest >90% probabilities of breaking 50
degrees, with >70% probability of breaking 60 degrees over the
southwestern third of the CWA. Thanks to these higher than normal
probabilities have bumped up temperatures into the lower 60s over a
large area of the forecast region.
Thursday night and Friday: The front should pass through the area
Thursday night, bringing a low chance for light rain/drizzle into
the overnight hours. We will have to watch for the potential of
freezing drizzle once the front passes and colder air tries to sink
southward into the area. Friday remains dry with high pressure
influencing the area.
Saturday-Monday: This is the most interesting period of the
forecast and one that will bear continued monitoring as we head into
the busy travel weekend. As mentioned yesterday, models solutions
continue to evolve in how they handle energy lingering across the
southwestern United States on Friday. The latest solutions are
slightly better aligned, with the GFS/GEM moving toward the ECMWF.
These solutions dig the upper energy into northern Mexico before it
is picked up by a deepening wave dropping southeast out of the
The eventual track of this upper wave remains in doubt, but the deep
and nearly meridional low level flow will transport copious amounts
of moisture northward into the Southern Plains and Mid-Mississippi
river valleys ahead of this system. The other question will be the
amount of cold air that drains into the region prior to the arrival
of this system and then where the low-level baroclinic zone
establishes itself. Either way, confidence is high in a potential
messy situation beginning Saturday and ending Sunday, but low
confidence remains on the p-type and amounts in the local area. A
system to be monitored if you have travel plans ahead of
.AVIATION...(For the 00Z TAFS through 00Z Tuesday Evening)
Issued at 555 PM CST MON DEC 16 2013
Complex aviation forecast problem concerning fog and low ceilings. A
previously stalled frontal boundary near a KSTJ to KCOU line has
surged southward since 20z, passing through all 3 terminals and
turning winds to the north. This has allowed the cold dense air to
overspread all the terminals although the low level moisture remains
in place. This sets up the potential for fog to reform this evening
over much of northern and central MO, including all 3 TAF sites.
Latest NAM Bufr soundings suggest MVFR fog should form mid/late evening
and is supported by the latest SREF and UPS fog forecast output. See
no reason to take out the previous MVFR to IFR overnight visibilities
and added IFR ceilings after midnight. Still banking on the WNW
surface winds to push out the fog/stratus. Overall confidence on the
above scenario is low. However, the airmass which supported dense fog
and IFR/LIFR stratus is now moving into west central and central MO.
Do believe there is a risk for dense fog to form later this evening
over parts of northern and central MO but most likely east of the