Tornado and Flash Flooding in Missouri, May 10 to 11, 2017

Area Forecast Discussion
National Weather Service Springfield MO
1158 PM CDT Wed May 10 2017

.SHORT TERM...(This evening through Thursday)
Issued at 236 PM CDT Wed May 10 2017

A moist and unstable airmass is in place across the area and this
will aid in the development of additional showers and storms
through Tonight. While the main synoptic front is located across
Northern Missouri west into Northern Kansas, an effective
front/trough is located further south from Central Missouri back
into West Central Oklahoma. Impulses riding up from the south have
contributed to pockets of storm development, most remaining just
to our north and west thus far. Will be watching the evolution of
storms across Southern and Central Oklahoma this afternoon and
evening as they approach the area ahead of a lead impulse over the
Red River Valley. The atmosphere is ripe for organized storms
with 1500j/kg of ML cape along with 40-50kts of effective bulk
shear. If storms can get organized then large hail and damaging
winds will be possible. Locations along and north of Interstate 44
are most favored for this activity.

Most model guidance thus far has struggled with the evolution of
showers and storms and thus caution must be used with them. There
is a signal that the heavier axis of showers and storms may be
pushed further south into our area tonight vs locations to our
north given a strong low level jet developing and interacting
with this trough/effective boundary. While uncertainty in this
scenario is high, it would have implications on our qpf amounts
overnight and this will need to be monitored. A severe threat will
exist for most of the night as the environment will not change
much. Shear profiles will actually become more favorable for
storms heading into the overnight hours.

There will likely be ongoing showers and storms Thursday morning
across the area and this will be key as to what it does with the
true synoptic front. Models have the front along the Interstate 44
corridor Thursday afternoon. Forecast soundings off the GFS reveal
a class splitting supercell profile with large hail being the most
prominent threat. Mid level lapse rates will be steep and CAPE
will be plentiful especially in the hail growth zone. Thinking
that robust thunderstorm development is possible along the front
in the afternoon with hail to the size of golfballs possible.
There is a conditional threat for a tornado if storms can ride the
front and increase effective helicities. This will be evaluated
more closer to tomorrow. A Slight risk for severe storms is across
most of the area for Thursday with locations along and south of
Interstate 44 most likely to be affected.

Lastly, with such a high moisture content and potential for
training storms, there is a locally heavy rainfall signal across
the area as well. Storm total rainfall amounts of 0.5 to 1.5
inches looks likely with some locations receiving 2 inches within
the heavier storms. This could definently cause some localized
flooding issues. Widespread flooding does not look likely at this
time however depending on overnight storms then the flooding
threat could be higher Thursday, this will be also be monitored
closely.

.LONG TERM...(Thursday Night through Wednesday)
Issued at 236 PM CDT Wed May 10 2017

Ongoing thunderstorms Thursday night will eventually end during
the morning hours Friday. Fantastic weather is expected for
Saturday through Monday. An active pattern returns by the middle
of next week with several systems potentially impacting the area
under a west to southwest flow regime.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1152 PM CDT Wed May 10 2017

KSGF/KJLN/KBBG tafs: Scattered thunderstorms will move through the
region at times. In the near term storms over sw MO and ne OK are
expected to produce mvfr/maybe brief IFR conditions with heavier
showers. A sfc front will veer winds to the nw and north late in
the taf period with the potential for mvfr and ifr ceilings.

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

SHORT TERM...Burchfield
LONG TERM...Burchfield
AVIATION...DSA

Hazardous Weather Outlook
National Weather Service Springfield MO
838 PM CDT Wed May 10 2017

KSZ073-097-101-MOZ055>058-066>071-077>083-088>098-101>106-120145-
Bourbon-Crawford-Cherokee-Benton-Morgan-Miller-Maries-Vernon-
St. Clair-Hickory-Camden-Pulaski-Phelps-Barton-Cedar-Polk-Dallas-
Laclede-Texas-Dent-Jasper-Dade-Greene-Webster-Wright-Newton-
Lawrence-Christian-Douglas-Howell-Shannon-McDonald-Barry-Stone-
Taney-Ozark-Oregon-
838 PM CDT Wed May 10 2017

This Hazardous Weather Outlook is for portions of the Missouri
Ozarks and extreme southeast Kansas.

.DAY ONE...Tonight.

Weather hazards expected...

  Elevated Hail risk.
  Elevated Thunderstorm wind damage risk.
  Limited Flooding risk.
  Elevated Lightning risk.

DISCUSSION...

Numerous showers and scattered thunderstorms will occur overnight.
The overall risk for severe storms has become lower somewhat, but
isolated strong to severe storms with one inch hail and wind
gusts of 60 mph will still be possible. Short term guidance
indicates that the overall activity will shift farther to the
southeast overnight into the I-44 corridor and counties just to
the south. Training storms may produce small areas of excessive
rain and flooding.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

A greater coverage of thunderstorms is expected area wide
Thursday into Thursday evening as a cold front moves into the
area. Strong to severe thunderstorms are possible with large hail
to the size of golf balls and damaging winds to 60 mph being the
main threats. If thunderstorms can remain on the front then a
tornado threat would exist. Locally heavy rainfall will also be
possible with these storms.

Total rainfall amounts up to an inch and a half are likely with a
few two inch amounts possible. This could result in localized
flooding issues through Thursday night.

.SPOTTER INFORMATION STATEMENT...

Activation is becoming less likely, but spotters should continue
to monitor local conditions.

&&

More detailed information can be accessed at:
http://www.weather.gov/sgf/sitrep

This product in graphical format...along with other weather...
hydrological and climate information...at
http://www.weather.gov/sgf

DSA

Special Weather Statement
National Weather Service Springfield MO
1209 AM CDT THU MAY 11 2017

MOZ090-094-110600-
Greene MO-Lawrence MO-
1209 AM CDT THU MAY 11 2017

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN LAWRENCE AND GREENE
COUNTIES UNTIL 100 AM CDT...

At 1209 AM CDT, Doppler radar was tracking a strong thunderstorm near
Ash Grove, or 9 miles northwest of Republic, moving northeast at 40
mph.

Dime size hail and wind gusts up to 50 mph will be possible with this
storm.

Locations impacted include...
Northern Springfield...           Willard...
Strafford...                      Ash Grove...
Fair Grove...                     Brookline...
Halltown...                       Sacville...
Glidewell...                      Ebenezer...
Bassville...                      Bois D'arc...
Cave Springs...

This includes Interstate 44 between mile markers 57 and 68, and
between mile markers 70 and 87.

LAT...LON 3727 9371 3729 9367 3728 9363 3731 9363
      3742 9340 3741 9308 3728 9308 3711 9361
TIME...MOT...LOC 0509Z 243DEG 34KT 3723 9358

Wise