Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO
FXUS63 KEAX 192216
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
516 PM CDT Sun May 19 2013
Issued at 514 PM CDT SUN MAY 19 2013
Convection is quickly growing upscale over central and eastern
Kansas with overall mode taking a quick transition to quasi-linear.
Still may see a few supercells ahead of this developing line capable
of producing very large hail, particularly across far northwest MO
and northeast KS. Overall tornado threat across that area is
relatively low at this time.
Large bowing structure developing near Emporia is taking a track
toward Kansas City, timed to arrive into the KC metro around 7 or 8
pm. As mentioned in an earlier discussion, low-level winds will
become increasingly favorable for bow echoes and embedded
mesovortices capable of producing very strong winds and tornadoes as
the line reaches the MO/KS border. Thus, there is increasing concern
for a potential widespread damaging wind event with a few embedded
tornadoes across east central Kansas and west central Missouri,
including all of the Kansas City metro. The potential also exists for
some significant wind gusts greater than 70 mph when the line
arrives. This wind and isolated tornado threat will continue eastward
later this evening toward central MO, but overall trends may be to
slowly weaken after the storms get east of KC.
.SHORT TERM...(This Evening through Monday Night)
Issued at 243 PM CDT SUN MAY 19 2013
Convection is already beginning to fire ahead of a north-south-
oriented wave over central KS. This wave will be the main player this
evening, and we still expect a line of supercells to develop just
ahead of it through late afternoon. This line should be near a TOP-
STJ line around 5 pm, into the KC metro between 6 pm and 9 pm and
toward Kirksville and Boonville between 9 pm and midnight.
Airmass has become moderately to strongly unstable, evident by 2600
J/kg of CAPE on the 18Z TOP sounding. This combined with a 50-60 kt
mid-level jet streak directly overhead will be more than supportive
of organized severe thunderstorms this afternoon and evening.
Still expect storms capable of very large hail and a few tornadoes to
develop over eastern KS which will transition into a line of storms
over far eastern KS or western MO and race into central MO overnight.
Latest models suggest this transition into linear or quasi-linear mode
may occur a bit earlier than previously thought, possibly as far west
as eastern KS. This line will be capable of producing widespread wind
damage and some embedded tornadoes. Better chances for strong
tornadoes now appear to be southwest of the forecast area, closer to
Wichita, where low-level wind fields will be a bit more supportive.
However, low-level shear will increase after 00Z across far western
MO, and this could support tornadoes embedded within a developing
QLCS as it tracks into Kansas City and points east. Any storms that
maintain supercell structure after 00Z will also have an enhanced
Another potentially active day is in store for Monday as wind fields
remain supportive of severe storms. Much of the severe threat for
Monday depends on how far south and east the cold front pushes
overnight, and any lingering cloud debris that could cut back on
instability during the day. Models have trended slightly further east
with the location of the front, and thus the severe threat, which now
appears to be focused from near Clinton and Sedalia toward Macon and
points east. If strong instability can redevelop, shear profiles
support a severe line of storms capable of large hail and widespread
wind damage developing across these areas and spreading into eastern
MO and the Ozarks Monday evening. Heavy rain will also be a threat
with this line.
.LONG TERM...(Tuesday through Sunday)
Issued at 243 PM CDT SUN MAY 19 2013
Have lowered thunderstorm chances on Tuesday as latest guidances
indicates convection Monday night may shove effective boundary far
enough to the southeast to push highest chances of redevelopment
into the southeastern portions of the state.
Through Friday, temperatures will return to seasonal normal in the
70s, as high pressure remains in control. Precipitation chances
begin to increase by next weekend as mid-level heights rise and
moisture returns to the Plains. Temperatures by next weekend will
again climb back into the 80s.
.AVIATION...(For the 18Z TAFS through 18Z Monday Afternoon)
Issued at 1238 PM CDT SUN MAY 19 2013
Line of storms is expected to rapidly develop later this afternoon
across eastern Kansas, ahead of a weak wave that is currently visible
as a band of altocumulus from GRI to SLN and west of ICT. While
timing is still somewhat uncertain, best guess at this time is that
this line of storms will approach the KS/MO state line around 00Z,
progressing toward IRK and COU toward 04Z, give or take a couple of
hours. These storms may be strong with large hail and severe wind