443
FXUS63 KTOP 191102
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
602 AM CDT Thu Sep 19 2024

.KEY MESSAGES...

- Severe storms may form over portions of far northeastern into far
east central Kansas areas this afternoon before moving ESE of the
area by mid evening. Large hail and damaging winds appear to be the
primary hazards with a very low tornado threat possible.

- Hot afternoon temperatures hang around possibly through Saturday.
Today (Thursday) may bring heat index values close to 105 degrees
mainly over east central into portions of northeastern Kansas along
and ahead of the frontal boundary.

- Good rain chances still in the forecast mainly Saturday night
through Sunday with 2-3 inches possible mainly north of I-70 and 1-2
inches elsewhere. Some area may see locally higher amounts.

- Cooler and mostly dry weather looks like the pattern heading into
next week with temperatures near seasonal normals.

&&

.DISCUSSION...
Issued at 335 AM CDT Thu Sep 19 2024

The overall upper air pattern across the CONUS shows an open trough
over the Mid-Atlantic region with an upper low spinning over the
Dakotas and another within an elongated trough over central
California. A semi-permanent anticyclone is in place over Texas with
a ridge axis extending into the Mid-MS Valley region. Near the
surface, a weak area of low pressure is situated over western Kansas
with a weak frontal boundary poised to work east today into the area.

Early this morning, mainly isolated showers and a few embedded
thunderstorms have formed within an area of warm advection
isentropic upglide working across the area along the 310K surface.
Expect these showers and storms to last through mid morning before
exiting the area to the east and then clearing into the late morning
and afternoon. The aforementioned surface boundary will likely be a
focus into the afternoon for storms to develop once the cap is
eroded sufficiently. Hot temperatures will be common ahead of this
boundary into this afternoon mainly across east central and into
portions of northeastern Kansas combining with dewpoints around 70
degrees to bring heat indices close to 105 degrees over some areas.
Have opted to not go with a headline for heat due to the relatively
isolated area along the boundary and this being a very late season
event after several previously hot episodes.

Storms for this afternoon into the evening are expected to be
isolated to scattered in coverage with forcing being focused well
north of the area. The low level lift will be provided by a weak
frontal boundary and area of low pressure advancing east into the
area. As the EML mixes out, expect more opportunity for storms to
fire with updrafts along or in the vicinity of the boundary. Mid
level lapse rates from H7-H5 levels isn`t forecast to be as steep
and one would like to see for some of the most robust updraft motion
with most progs around 6C/km. Nonetheless, with good low level
moisture in place and the low level lift mechanism in place, could
see updrafts organize in areas as a deeper layer of effective shear
comes into play with 0-6km values around 30-40kts. Surface winds
appear to remain mostly southerly to slightly southwesterly. Thus,
for this afternoon areas generally along and southeast of the Kansas
Turnpike appear to have the best ingredients in place with a deep
inverted-V sounding in place. Expect hazards to include damaging
winds possibly up to 70, large hail over quarter size with a very
low tornado threat which can`t be totally ruled out mainly along the
weak frontal boundary.

Widespread rain chances still look possible into late Saturday and
Sunday periods as the upper low over central California lifts into
the central Rockies and ejects into the central Plains. Strong mid-
level flow around the mid to upper low should provide ample DCVA to
set up across the forecast area. Strong low to mid-level theta-e
advection brings back PWATs to above the 90th percentiles. Depending
on how much convection develops within this this system, some
rainfall totals could exceed 3 inches, especially north of I-70
within the region where the best convergence and resulting
precipitation shield looks to establish itself. Any severe weather
with this system is too uncertain to ascertain where it would setup
at this point due to the nature of the forcing that is expected to
be in place both from a temporal and spacial sense.

Into next week, a northwest flow pattern sets up with drier and
cooler air entering the region helping to bring temperatures back to
around normal for this time of year with highs in the 70s and lows
in the 50s.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 557 AM CDT Thu Sep 19 2024

VFR conditons outside of passing showers and storms near
KTOP/KFOE terminals in the first couple of hours of the TAF
cycle. Chances for showers and storms re-forming this afternoon
still look best ESE of KTOP/KFOE terminals. Wind shift should
take place at KMHK by late afternoon but forward progress of the
front slows as it advances east delaying shifts at KTOP/KFOE
until late evening. Light winds accompany the  due to the weak
overall advection with this system.

&&

.CLIMATE...
Issued at 235 PM CDT Wed Sep 18 2024

Record high temperature data for September 19:

           Record maximum temperature   Forecast maximum temperature
Topeka     99,       set in 2022                    96
Concordia 101,       set in 2022                    92

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Drake
AVIATION...Drake
CLIMATE...Poage