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Area Forecast Discussion (AFD)

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

                            
000
FXUS63 KEAX 220922
AFDEAX

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
422 AM CDT Sat Jun 22 2019

.Discussion...
Issued at 422 AM CDT SAT JUN 22 2019

Water vapor imagery this morning continues to show a large trough to 
our west, with a very tight circulation lifting north into the 
Canadian Plains; which is dragging a frontal boundary across the 
Northern and Central Plains early this morning. A lee side surface 
low is noted across the panhandles of Texas and Oklahoma in response 
to the larger western trough, with a frontal boundary stretching 
east northeast to just south of Kansas City early this morning. The 
jet ahead of the western trough over ran the east-west Kansas 
boundary earlier Friday evening, generating convection that swept 
east overnight. New elevated storm activity is now noted 
percolating in far northern Missouri in its wake of the leading 
round of storms as the persistent southwest flow across the 
Central Plains, ahead of the western trough and surface low, 
continues to over run the boundary and/or any cold pool in 
eastern Kansas and western Missouri. Otherwise, looking back to 
the west, a subtle shortwave trough is seen rotating under the 
base of the western trough into Kansas, and it has helped focus 
the prevailing southwest flow and nocturnal jet to generate 
another round of storms in western and central Kansas over the 
past few hours. Latest radar returns show cells out in Kansas 
starting to congeal into a more robust convective complex, and it 
will likely be some form of this complex that we will be dealing 
with later this morning, and maybe this afternoon. 

Models overnight have been a bit all over the place as they try and 
pin down all the convective elements kicking around the Central 
Plains this morning, so have leaned a bit more into short term 
conceptual "gut" model, with a heavy dose of the RAP. Convection 
still trying to percolate across far north central and northeast 
Missouri is getting a bit of help from the edge of the 850mb jet, 
but convection back in central Kansas is going to start intercepting 
that flow more and more in the next few hours. As a result, don't 
think that activity in north central Missouri will last long, 
either shifting east or simply dissipating in place through 
sunrise. However, activity in Kansas will likely develop into some
kind of MCS as the 850mb jet keeps pumping moisture into from the
southwest, with a bit of a warm wing of activity lifting across
eastern Kansas. As a result, think that this activity will shift 
east early this morning, though slowly, eventually making it into 
western Missouri after sunrise this morning. Elevated CAPE will be
more than sufficient in combination with 0-6KM shear values in 
the 35 knot range to keep the threat of severe weather running 
into the morning hours as the storms move in. All that said, what
models advertise this activity making it to Missouri show the 
storms fading fast as they get into the border, but thoughts are 
that models are not handling the cold pools that are helping drive
some of the convective activity, and are mixing out, or at a 
minimum, decreasing the jet a bit too quickly this morning. Hail, 
strong to damaging winds, and torrential rain with flash flooding 
will be possible with any storms this morning. 

For this afternoon and evening; much will depend on the morning 
activity. There is a decent possibility that there will be a MCV 
spinning its way across northern Missouri this afternoon, as left 
over from the central Kansas activity this morning. That said, 
models are focusing on activity starting out in Kansas as the 
large western trough edges into the Plains as another shortwave 
trough rounds it base; which all the operational, ensemble, and 
CAMs are in good agreement on. Warm air advection ahead of the 
large trough, with hot and humid conditions prevailing today, will
help set the stage for more strong to severe storms this 
afternoon and overnight. Expect afternoon MLCAPE values to be 
greater than 3000 J/KG, but shear values will be a bit marginal 
due to the best upper level jet dynamics being closer to the upper
level trough, which will still be out in the western Plains. So, 
while strong to severe storms will be possible, the main modes of 
convection look a bit linear, and thus more of a hail, and wind 
threat. Additionally, precipitable water values will still be in 
the 1.5 inch range, which will likely make storms very efficient 
rain makers. We may need another Flash Flood Watch for tonight as 
a result, but will let the day crew get observations on 
precipitation from overnight and put that together with the 12Z 
model runs to see where a Watch might best be placed for tonight.


&&

.Aviation...(For the 06Z TAFS through 06Z Saturday Night)
Issued at 1116 PM CDT FRI JUN 21 2019

Nearby storms will continue off and on through the overnight hours
with heavy rain possible where storms do develop. Marginal low
level wind shear is possible as winds near 2kft approach 35 knots
between 06Z to 08Z early in the forecast period Friday night. Will
see storms dissipate toward sunrise before additional development
is possible late Saturday afternoon.


&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...Flash Flood Watch until 7 AM CDT this morning for MOZ002>008-
     012>017-022>025-031>033-039-040.

&&

$$

Discussion...Cutter
Aviation...Welsh