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Area Forecast Discussion (AFD)

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

FXUS63 KEAX 180854

National Weather Service Kansas City/Pleasant Hill MO
354 AM CDT Sat May 18 2019

Issued at 350 AM CDT SAT MAY 18 2019

Active weather likely today/tonight with threat for strong to severe 
weather and localized flash flooding. As of early this morning, a 
weak line of thunderstorms were generating along a thunderstorm 
outflow boundary from northwest MO into central KS, aided by a 50kt 
low-level jet. Most high-res model guidance has done a poor job 
resolving this activity, minus the ARW/NMM. Current indications are 
this activity will shift into the northwest half of the forecast 
area through mid-morning. The trend has been a gradual lack of 
organization/weakening as storms run ahead of strongest 
forcing/instability and expect this trend to continue. The true cold 
front will briefly become quasi-stationary over eastern Kansas by 
mid/late morning in response to pressure falls to a developing low 
pressure over south central Kansas. As the upper trough ejects into 
the central Plains, rapid thunderstorm development is expected 
between 11am-1pm over eastern Kansas into northern Missouri in 
proximity to both the synoptic front and the ongoing outflow 
boundary expected to be draped over the forecast area. This 
widespread cluster of storms will develop/move into an area of 
moderate instability (~2000 J/kg), and will have some strong to 
severe weather potential, mainly in the form of large hail and 
locally damaging winds. This activity is anticipated to overspread 
much of the forecast area during the afternoon hours before exiting. 
With steady movement of storms and the lack of saturated soils, 
widespread flash flood should largely be avoided with this initial 
round. One and three hour flash flood guidance is nearly 2"+ for most 
areas, and should not exceed that in most locations. Models hint at 
additional thunderstorms closer to the surface low, moving northeast 
towards the forecast area during the evening hours. Severe weather 
threat with this secondary round is highly uncertain due to the 
degree of environmental recovery in the wake of the midday/early 
afternoon convection. Will have to closely monitor the corridor of 
heaviest rainfall that could potentially track/train over areas 
earlier impacted for a flash flooding threat. All said in done, most 
areas should receive 1.50-2" with locally higher rainfall amounts 
between this morning into Saturday night. 

Shortwave ridging and cold air advection will allow for a tranquil 
and cool Sunday and Monday morning, with precipitation shifting east 
of the area by late Sunday morning and highs in the middle 60s to 
lower 70s both afternoons. This quiet weather will be short-lived as 
an active weather pattern continues across the central CONUS with 
another strong upper trough emerging into the Plains on Monday. 
Elevated convection forming along/north of a warm front laid from SW 
MO into SE KS is expected Monday night. The convection may also tend 
to shrink/narrow the warm sector as the upper trough ejects into the 
central Plains. The timing of the cold front passage is also a 
little early - late AM into early afternoon. Therefore, the overall 
severe weather threat remains in some question. Another heavy rain 
event may also materialize with repeated convection, with 2-3 inches 
possible across the western half of the forecast area. This would 
certainly cause potential river and flash flooding issues. 
Precipitation should clear the area around sunset Tuesday, with a 
dry daytime Wednesday expected. 


.Aviation...(For the 06Z TAFS through 06Z Saturday Night)
Issued at 1148 PM CDT FRI MAY 17 2019

Low confidence forecast this go around as models do not have a
good grasp on ongoing convection early this morning. The first
round of showers across central Kansas is timing to approach the
terminals around 10Z but should remain north of the TAF sites. The
main round of showers and thunderstorms is expected to approach
from the south btn 16Z-18Z and affect the terminals much of the
afternoon and evening hours. There should be a break in the storm
during the evening however a second round of storms is expected
with the passage of a surface low during the evening. Best timing
for the second round of storms appears to be 02Z-06Z right now.
Otrw...cigs should remain VFR expect during storms when MVFR
cigs/vis will be poss. Winds will be out of the south around 15kts
with gusts to around 25kts thru tomorrow evening when winds will
diminish to around 10kts.