253
FXUS63 KICT 301812
AFDICT

Area Forecast Discussion
National Weather Service Wichita KS
112 PM CDT Tue Apr 30 2024

.KEY MESSAGES...

- A few severe thunderstorms expected this afternoon/evening east of
  Intestate-135

- A period of heavy rain tonight across southern/southeast KS
  may lead to additional flooding/river flooding

- Another round of severe storms possible Wednesday afternoon/evening

- The active weather pattern continues into the weekend

&&

.DISCUSSION...
Issued at 303 AM CDT Tue Apr 30 2024

As of 3 AM this morning, an area of midlevel WAA was generating very
isolated showers/storms across the Flint Hills. These should come to
an end by sunrise. Further west, a midlevel low was coming ashore
across the Pacific northwest with an attendant 120 kt speed max.
Further deepening of a surface low across the high Plains will surge
low-level moisture northward with dew points returning to the 60s
for most locations. By mid to late afternoon, the surface low will
remain across southeast CO with the inverted trough extending into
north central KS. Latest deterministic and ensemble guidance place
the dryline around 4 PM from near Omaha, NE to Manhattan, KS to
Wichita. As a lead, midlevel shortwave trough ejects across NE this
afternoon, widespread thunderstorm development is expected along the
dryline/trough axis across NE. Large scale forcing for ascent
decreases with southern extent into portions of KS. That being said,
modest surface convergence along the dryline from Newton to
Manhattan may yield convective initiation in the 4-6 PM timeframe.
Long, veering hodographs combined with MLCAPE between 3000-4000
J/kg will support supercells capable of baseball sized hail and
damaging winds up to 70 mph. Furthermore, effective storm
relative helicity will increase to near 200 M2/S2 by 6 PM, which
suggests a tornado is possible as well.

After 6 PM, the main trough axis is forecast to begin overtaking the
dryline from north to south. Increased convergence along the boundary
should support more-widespread thunderstorm development from roughly
Hillsboro to Wichita. While the overall hodograph structures remain
favorable for discrete supercells, the linear forcing along the
boundary should grow convection upscale into more of a linear
fashion with embedded supercells possible. As such, the hail and
tornado threat will gradually decrease after 7 PM, while the
damaging wind and flooding threat are likely to increase. The line
segments/MCS will gradually dive south and southeast into the
highest zone of low-level theta-e across southern KS. As the
convection becomes displaced from the midlevel shortwave trough
after 10 PM, the southward push will likely come to an end. The
cold pool orientation will remain largely east to west. As the
evening progresses a 50-60 kt LLJ will overspread the western
flank of the cold pool. This seems to point towards a setup for
training storms across southern/southeast KS for a good chunk
of the night. Rainfall rates are likely to be quite efficient
with PW values forecast to range from 1.25-1.50", which would
approach May 1st daily maximums. All of that to say, have
hoisted a Flood Watch across southeast KS due to the ongoing
flooding issues and the likelihood for more heavy rain.

Transitioning from Tuesday night into Wednesday, a complex and
potentially significant severe weather setup will emerge. WAA
driven showers and storms across southern KS are likely to
continue through much of the morning hours. On the western flank
of the convection, low-level moisture should being to surge
northward as a warm front retreats north. The main uncertainty
with Wednesday is the eastern bound of the warm sector. Forecast
soundings suggest this WAA pattern atop of thick low-level
stratus deck may shunt the buoyant sector west of I-135. Should
the stratus scatter by early to mid- afternoon, the background
environment will become increasingly favorable for supercells
with all hazards probable. These threats would include very
large hail up to baseball size, damaging winds up to 70 mph, and
tornadoes. Impressive low-level veering with upwards of 200-
300 M2/S2 of effective SRH would support a significant tornado
threat with the most intense supercells. These mesoscale details
will have to monitored through the morning/afternoon hours
Wednesday to truly delineate the greatest severe weather threat
area. Similar to Tuesday night, as the trough axis overtakes the
dryline, more-widespread thunderstorm development overnight
across eastern KS. The chief concern overnight will be heavy
rain and flooding.

The main midlevel trough will eject across the central Plains
Thursday afternoon/evening. The aforementioned surface trough will
reside across eastern KS by afternoon. Additional storm development
is expected Thursday afternoon/evening along the front. The active
weather pattern looks to continue into the weekend with a series of
shortwave trough axis` ejecting into the Plains.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1249 PM CDT Tue Apr 30 2024

A number of aviation concerns are expected over the next 24
hours.

SCT to BKN MVFR cigs are slowly moving eastward across south-
central Kansas early this afternoon, but shouldn`t affect TAF
sites from here on out. VFR conditions should prevail at most
TAF sites until about 22Z.

A weak frontal boundary/dry line sliding across the area, and a
pronounced wind shift from southerly to northwest/westerly.
Sustained winds are generally around 15 to 20 knots with gusts
up to 30 to 35 knots on both sides of the boundary.

By 22Z, thunderstorm development is anticipated along the
boundary, and a line of broken strong to severe storms will
gradually slide eastward through the late afternoon and evening
hours along and east of the Kansas Turnpike. The main concerns
will be very large hail, damaging wind gusts, and perhaps a
tornado or two. These storms may impact KICT, but it`s
difficult to go with more than a PROB30 at this time given
coverage may be isolated. Storms are expected to continue moving
eastward tonight, and KCNU may also be impacted later tonight.
Additional thunderstorm development is expected during the
nighttime hours into Wednesday morning, but this activity is not
expected to be severe. However, frequent lightning and heavy
rainfall may accompany these storms Wednesday morning.

&&

.ICT WATCHES/WARNINGS/ADVISORIES...
Flood Watch from 8 PM CDT this evening through Wednesday
morning for KSZ069>072-093>096-098>100.

&&

$$

DISCUSSION...BMB
AVIATION...JC