088
FXUS63 KTOP 190528
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
1228 AM CDT Thu Sep 19 2024

.KEY MESSAGES...

- Isolated showers/storms possible across the area today, mainly
north of I-70. (10-20%)

- Isolated to scattered storms will be possible again Thursday
afternoon and evening across northeast and east-central KS. A few
could become strong/severe with damaging winds to 70 mph and hail up
to 1.5 inches possible.

- Warm temperatures persist today and into Friday before cool air
filters in this weekend and next week.

- Widespread chances for rain come Friday PM through Sunday with
  areas seeing a widespread 1 inch of rainfall. Some areas could
  receive totals up to 2-3 inches, mainly north of I-70.

&&

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

This afternoon, the main synoptic features across the CONUS include
an occluded upper low across the northern Plains, a longer-wave
trough over the northern CA coast and weak ridging over the central
Plains into the Ohio River valley. A warm and pleasant day is
underway today as temperatures have climbed into the low to mid 80s
area-wide with some mid and high cloud cover pushing east across the
area. Expect temperatures to warm a few degrees further this
afternoon, topping out in the upper 80s, low 90s. An isolated shower
and possibly a storm could develop this afternoon if surface
convergence can help parcels overcome residual SBCIN, but overall
forcing and upper-level support does not seem conducive to much
development. If one can develop, some gusty winds and small hail
could be realized in the strongest of storms.
This evening, isentropic ascent ramps up as a nocturnal 30-40kt LLJ
develops across the area. Isolated showers within this regime will
be possible through the early morning hours of Thursday.

By Thursday afternoon, a low-level trough axis and frontal boundary
will begin to slide east into the area in unison with the main upper-
level wave over the northern Plains. Skies will begin to clear from
morning`s showers with mostly clear skies helping to destabilize the
environment during the day. Deep mixing paired with good solar
insolation should push temperatures into the mid 90s by the
afternoon with dewpoints creeping into the mid to upper 60s. CAMs
depict afternoon MLCAPE values ahead of the surface trough/frontal
boundary ranging from 1500-2500 J/kg with 7-8C degree ML lapse
rates. Increasing deep shear and inverted-V soundings should also
point to a severe threat as 30-35 knots of 0-6 km shear should be
realized in combination to the afternoon instability. Given these
parameters and the low-level convergence along the surface boundary
and trough axis, scattered convection should develop in the peak
heating hours across far northeastern and east-central KS as any
SBCIN erodes. Hazards within the strongest storms will be winds to
70 mph, and hail up to 1.5 inches. The tornado threat is very low,
but not zero given LCLs around 1-1.5 km, slight curvature in the low-
level hodographs and storm motions moving off of the surface
boundary into the warm sector. Some uncertainty may come with how
long cloud cover from morning showers impacts heating across eastern
Kansas. If cloud cover can hold on for a bit longer, some capping
may remain in place into the afternoon hours making storm coverage
in the late afternoon and evening even more isolated. Storm chances
will quickly move into western MO by the late evening hours tomorrow
with drier air filtering in overnight into Friday.

By Friday and Saturday, the weak frontal boundary stalls across
southeastern Kansas before lifting north as a warm front during the
day Friday in response to our next upper wave approaching from the
southwest. PoPs should begin to increase along this boundary as it
approaches the KS/NE border by Friday evening. PVA will increase
Saturday and through the weekend as the main long wave trough ejects
into Kansas and Nebraska, providing the area with much needed
rainfall. Saturday afternoon through Sunday morning appears to be
the timeframe when the area should see the highest rainfall totals
given ample low and mid level convergence, persistent theta-e
advection and PWATs hovering around 2 inches; around the 90th
percentile for this time of year! Majority of the aforementioned
forcing should occur north of I-70 and is where the highest rainfall
totals are expected to reside, some seeing 2-3 inches. Areas south
of I-70 will see a bit less, possibly between 0.5-1.5 inches.
Temperatures Saturday should vary from north to south, topping out
in the low to mid 80s and upper 80s respectively with temps Sunday
mostly staying in the 70s.

PoPs will push east by Monday as northwesterly flow builds into the
region and reinforces cool, Fall-like temperatures behind the
weekend`s rainy system. Expect temperatures in the 70s each
afternoon with lows dipping into the 50s next week with low chances
for precipitation.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1222 AM CDT Thu Sep 19 2024

VFR conditions expected to remain in place for most of the
period as chances for showers and thunderstorms appear to be low
at all terminals. LLWS conditons continue to look marginal at
this hour with partially mixed surface winds likely to remain in
place overnight. Best chance for afternoon showers and storms
appear to be around or just ESE of KTOP/KFOE terminals. Chances
remain too low to include in the forecast but expect best time
to form around 21Z or after and lasting through around 03Z
before moving SE of the area. A weak front enters the area after
the 00Z time frame but winds look to be lest than 10kts at this
time.

&&

.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                    95
Concordia 101,       set in 2022                    92

&&

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

&&

$$

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