Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO

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FXUS63 KEAX 251739

1139 AM CST Tue Nov 25 2014

Issued at 247 AM CST TUE NOV 25 2014

Today through Wednesday: A quiet weather day is in store for the
area today. A relatively dry atmosphere will yield mostly sunny
skies. Temperatures will remain cool today, with highs in the middle
30s to middle 40s. The axis of a positively-tilted longwave trough
will move across the CWA today, with the attention eventually turning
upstream to a well-defined clipper system moving towards the region.
Models continue to converge towards very similar solutions regarding
the timing and location of the clipper system. Model cross-sections
depict the best lift to arrive between 06-12Z Wed. While this
disturbance will be quick-moving, the vertical column should quickly
saturate upon strong low-level ascent in the H85-H65 layer. This lift
is located atop strong frontogenesis as the disturbance moves
through. The dynamics favor precipitation to develop and move across
portions of the area, although the duration of the highest
precipitation rates should be short-lived due to the fast-moving
nature of the system. The highest probabilities for precipitation
will remain generally east of I-29 and north of I-70, primarily
northeast of the Kansas City metro area. Another challenge is
forecasting the vertical temperature profile with regards to wintry
precipitation. While models agree to introduce ice into the column,
there is some concern in the lowest couple thousand feet AGL.
Following wet-bulb effects, there is some uncertainty of a small warm
layer that may exist, especially on the western and southern
outskirts of the precipitation region. Further northeast into north
central and northeast Missouri, slightly cooler air and higher
precipitation rates dynamically cooling the column should provide a
much higher probability for snowfall. In contrast, areas along I-29
and along/south of I-70 have a higher uncertainty of snow, with a
rain/snow mix possible. The end result will be the highest potential
for snowfall accumulations between midnight to noon Wednesday will
reside east of I-29, north of I-70 (NC/NE Missouri), where 0.5" to 1"
of snow may accumulate.

While the majority of precipitation will come to an end late
Wednesday morning, light precipitation may reform as the clipper
system departs. Models show a highly saturated layer in the lowest
4kft, with weak ascent centered near H85. Ice is introduced into
this saturated layer, so where wet-bulbing effects manage to cool the
small warm layer off the surface, some flurries, light snow, and/or
light rain will remain possible through Wednesday afternoon across
the CWA before precipitation ends by early evening.

Extended: Models during the the extended period have decent
consensus. One final shot of cold air is projected to move through
the region on Thursday as surface high pressure builds into the
region. While Thanksgiving day will be chilly with highs in the upper
20s northeast to the lower 40s southwest CWA, dry weather will
prevail. On Friday, weak upper ridging across the western two-thirds
of the CONUS will provide a large and fairly aggressive warm air
advection regime over much of the Great Plains, spreading eastward.
For instance, H85 temperatures near Kansas City are still projected
to increase by 12C during a 24-hour period from Thursday evening to
Friday evening. With surface high pressure sliding off to the east,
southerly winds will return on Friday. The end result is a quick
warmup Friday into Saturday, with afternoon temperatures in the upper
40s to upper 50s. A few locations may sneak into the 60s Saturday
afternoon. Precipitation is not expected during this multi-day period
of warm weather, making for an optimal time for any outdoor
activities. A cold front will move through Saturday night, reaching
the I-44 corridor by Sunday afternoon. This will effectively knock
our temperatures back down, with highs Sunday in the middle 30s north
to near 50 south. Cold weather will persist into Monday, before the
front retreats northward bringing with it warmer air on Tuesday.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1128 AM CST TUE NOV 25 2014

VFR conditions will continue into this evening before MVFR ceilings
move in later tonight. High clouds will increase in coverage through
the evening as a quick clipper system nears the region. Low clouds
will build area by 6-9Z with a rain/snow shower mix possible...little
to no accumulations are expected at the terminals. As the system
swings through winds will veer around to the northwest and become
gusty through the remainder of the period.




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