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Area Forecast Discussion (AFD)

Issued by Kansas City/Pleasant Hill, MO (EAX)

                            
000
FXUS63 KEAX 212341
AFDEAX

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
541 PM CST Thu Feb 21 2019

.Discussion...
Issued at 427 PM CST THU FEB 21 2019

A broad swath of cirrus across the region today in response to a 
trough digging into the Great Basin and Desert Southwest increasing 
southwesterly flow aloft. Temperatures will start their slight 
warming trend that will continue through Saturday. Clouds will 
continue to increase in coverage today as moisture advection ramps
up this evening and overnight. Drizzle and scattered light rain 
showers will start to spread north into southeast Kansas and 
southern Missouri by early Friday morning. There is some concern 
that temperatures will be hovering near freezing as the drizzle 
pushes into the southern counties of the CWA Friday morning; 
however, temperatures should climb above freezing pretty quickly 
after sunrise so any freezing drizzle chances should be rather 
brief in duration. Periods of drizzle and light rain showers will
continue to spread north through the day Friday, and even though 
temperatures will be above freezing, it will still make for a 
rather dreary day. Freezing drizzle once more becomes a concern up
across northern Missouri Friday night into early Saturday as 
overnight temperatures drop back into the lower 30s. 

Saturday looks to be an interesting day with the potential for 
periods of freezing drizzle early then rain showers with the 
possibility of isolated to scattered thunderstorms through late 
afternoon, and finally ending with a transition over to a wintry 
mix and snow Saturday night into Sunday morning. Strong warm air 
advection ahead of this system combined with an open Gulf will 
allow for a few hundred Joules of CAPE Saturday morning and 
afternoon. Severe threat looks to remain well south of the 
forecast area...primarily across Arkansas and extending eastward 
along the lower Ohio River Vally. The upper low will approach the
region Saturday afternoon with surface low generally tracking 
across Kansas from southwest to northeast then on up into Iowa. 
Rain will quickly transition to snow late Saturday afternoon and 
evening with the arrival of cold air on the backside of this 
system as it moves across northeast Kansas and northwest Missouri.
Models are still in fairly good agreement with the overall track 
of the system, but are still slightly off on timing. However, with
a narrow band of heavy snow expected in the deformation 
zone...even being slightly off can have significant impacts on 
the placement and timing of this band of snow. Currently, it looks
like far northwest Missouri will see the greatest snowfall 
amounts and the greatest impacts Saturday night, thus a Winter 
Storm Watch has been issued for this area beginning Saturday 
afternoon and continuing through Sunday morning. Strong winds will
accompany this system and this will create additional hazards in 
the way of blowing and drifting snow and greatly reduced 
visibilities...especially in rural areas. 

Another potential impact to keep an eye on with this system will be 
the potential for flooding. Given that much of the region has seen 
round after round of precipitation this month...area soils are 
extremely saturated and any additional rainfall will quickly run 
off. With thunderstorms possible Saturday and the chances for 
periods of more substantial rainfall with any thunderstorm
activity, we will see impacted drainages and rivers rise pretty 
quickly. We will also have to keep an eye on the potential for 
areal flooding and possibly flash flooding.

Behind this weekend system, zonal flow will keep us on the cool side 
with the next chance for precipitation around the middle of next 
week.

&&

.Aviation...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 541 PM CST THU FEB 21 2019

VFR conditions will hold up overnight and into the early morning.
However, guidance is conflict on timing and location of patchy 
light freezing drizzle near sunrise. Not confident atmosphere will
saturate by early morning when temperatures are below freezing. 
At this time, have opted to leave out mention of any precipitation
tomorrow morning. That said, saturation will eventually occur 
tomorrow as ceilings lower to MVFR and IFR levels throughout the 
day. By evening, light rain will spread across all TAF sites with 
timing near or after 23/00Z. Winds will remain from the east at 
10kts throughout the forecast period.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...Winter Storm Watch from Saturday afternoon through late Saturday 
     night for MOZ001-002-011.

&&

$$

Discussion...Pietrycha
Aviation...CDB/Otto