Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO
FXUS63 KEAX 211014
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
414 AM CST Fri Nov 21 2014
Issued at 414 AM CST FRI NOV 21 2014
Early morning satellite imagery paints a messy picture for the
center of the Nation as several shortwave troughs are poised to
bring the Lower Missouri River Valley a bit of wet weather this
weekend. Specifically, water vapor imagery currently highlights a
few different shortwave trough that will be interacting through the
weekend, bringing us near normal temperatures along with some rain.
First shortwave trough is noted tracking across the Texas panhandle
this morning, with a reflected surface low across north central
Texas. IR satellite imagery and surface observations both show
decent moisture return from the Gulf early this morning as the
surface low wraps the moisture into Oklahoma. However, this self
same shortwave will likely prevent the moisture from racing much
farther north as the upper level trough continues to shift east into
a confluent flow aloft. This wont completely stop the moisture from
moving north, it will just take a little longer, inhibiting
saturation and ultimately slowing down the onset of precipitation.
Lift continues to look weak at best, but what there is will be the
result of isentropic accent from the persistent warm air advection.
This continues to look merely sufficient for drizzle and/or showers
today and into tonight with low accumulations totals. Also, the
slowly timing will likely leave surface temperatures warm enough to
warrant stripping out the mention of freezing drizzle. In fact, warm
air advection might be sufficient to force rising temperatures
across the region after midnight tonight.
A second shortwave trough is making landfall across the California
Coast, and will track farther south across Texas and ultimately
along the Gulf Coast late in the weekend. This next trough will help
keep the cloudy rainy conditions brought by the first trough in
place across the central Plains as the Gulf moisture transport keeps
working through the weekend. This will keep the pump primped for a
third shortwave trough that will move through the Northern Rockies
into the Plains States late in the weekend. This should keep
scattered showers a possibility through the day Saturday, though the
focus for highest POPs is still on Saturday night through Sunday as
the third trough digs into Plains States. Highest precipitation
amounts will likely be across southern and eastern Missouri.
After the passage of the third trough, and it associated cold front
Sunday afternoon and night, temperatures will quickly sink back well
below normal. These colder conditions will likely persist though the
first half of the next work week as a progressive, but broad, trough
slowly shifts east across the Nation. The northwest flow that this
slow moving trough will likely bring by the middle of next work week
may result in a fleeting potential for some quick bursts of snow
starting next Wednesday. Confidence is not high, but the potential
is there for Wednesday night through Thursday currently.
.AVIATION...(For the 06Z TAFS through 06Z Friday Night)
Issued at 1129 PM CST THU NOV 20 2014
VFR conditions overnight will give way to building cloud cover
during the morning hours Friday as winds transition to southeasterly.
Scattered showers will commence in the early afternoon with MVFR
conditions expected initially. Further reduced ceilings and
visibilities may begin to come into play toward the end of the
forecast period as light drizzle edges in from the south.