173
FXUS63 KICT 300808
AFDICT

Area Forecast Discussion
National Weather Service Wichita KS
308 AM 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 /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1243 AM CDT Tue Apr 30 2024

Isolated showers from a mid-level cloud deck will continue to
affect areas of central Kansas along the I-70 corridor during
the early morning predawn hours. Other VFR conditions will
prevail across central and southeast Kansas thru Tuesday
afternoon. South winds will become strong and gusty ahead of a
cold front which is expected to move across central Kansas
during the late afternoon. As this front encounters better
instability toward early evening, strong to severe storms are
expected to develop southward along the front as it moves into
south central and southeast Kansas. For now have inserted VCSH
in these areas during the evening, though as confidence on timing
and coverage increase with later forecast issuances a prob30 or
tempo group can be expected.

KED

&&

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

&&

$$

DISCUSSION...BMB
AVIATION...KED