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

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FXUS63 KEAX 192022
AFDEAX

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
322 PM CDT Fri May 19 2017

.Discussion...
Issued at 321 PM CDT FRI MAY 19 2017

The upper level low continues to slowly make its way toward our
area, bringing us the potential for a couple rounds of storms. The
first round, currently entering the area, brings with it the
potential for severe weather. The severe weather window is now
through a couple of hours after sunset. The general set up is an
upper shortwave is heading over the area from the southwest, while
at the surface an east/west oriented stalled synoptic boundary is
in place near the MO River. The biggest area of concern is going
to be south of this boundary in central MO, along an east/west
oriented surface outflow boundary located just south of I-70. The
clouds have been able to clear some in this area which has
allowed instability to increase to about 500-1000 J/kg. 0-6 km
shear values of around 40-45 kts are also just enough to support
organized convection. Dewpoints across this area have already
reached the mid 60s, so there is also plenty of moisture. The
main threats with these storms are going to be hail up to about 1
inch, strong to damaging winds, with an isolated tornado or two
also possible. Therefore, we have issued a Tornado Watch in
central MO, which is in effect until 10 pm tonight.

There is also the potential for a second round of storms moving
through later tonight. As time has gone on today it has started to
look like we may not get quite as much QPF as originally thought.
The HRRR shows the bulk of the second round moving through
southern/eastern MO, dry slotting KC and surrounding areas early
on, while the NAMNest and RAP are showing more rain over the area
before the dry slot moves over us. Despite these differences,
PWAT values are averaging out around 1.5 across the area which is
well above the normal for this time of year, 0.99. In addition,
the ground is saturated from yesterday`s storms. Therefore, if
convection does get going behind the first round of storm, it
won`t take much to have some flash flooding and river flooding
concerns. Have gone with somewhat of a blend in the forecast and
think most of the forecast area will see about 1-2 inches of rain
from the second round of storms. The flash flood watch will
continue due to the potential and we will continue to monitor
river levels.

Things should dry out west to east by tomorrow morning as the
surface low and upper level low move off to the northeast over the
Great Lakes. A cold front will move through behind the convection,
cooling temperatures into the 60s and 70s for the rest of the
weekend. A surface high will settle in behind the cold front with
more zonal flow aloft. This will keep us dry until Monday, when a
shortwave moves over the area. Can`t rule out severe weather
given the time of year and overall pattern.


&&

.Aviation...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 1236 PM CDT FRI MAY 19 2017

MVFR ceilings will prevail for the first part of the period for
most of the area. Temporary IFR/LIFR visibilities will be
possible this afternoon as convection producing heavy rain moves
into the area from the southwest. Convection is expected to arrive
in the 19Z- 21Z time frame. Storms and heavy rain should stick
around for a majority of the period, moving off to the east by the
morning hours. A surface low is going to move through the area as
well tonight and as it does so, ceilings and visibilities should
drop to IFR conditions. Visibilities should gradually increase as
convection pushes to the east. As for ceilings, they should
gradually lift to MVFR ceilings within the last couple hours of
the period.


&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...Flash Flood Watch through Saturday morning for KSZ025-057-060-
     102>105.

MO...Flash Flood Watch through Saturday morning for MOZ011>014-
     020>023-028>031-037>039-043>045-053-054.

&&

$$

Discussion...Grana
Aviation...Grana



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