Manhattan, Kansas 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

611
FXUS63 KTOP 152333
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
633 PM CDT Fri May 15 2026

.KEY MESSAGES...

- A hot and humid airmass is expected to stick around this weekend
  and could break some records for highs and warm lows.

- The heat and humidity will bring a potential for severe storms each
  afternoon. Although thunderstorm development is not guaranteed. If
  you have outdoor plans, be sure to check the latest forecast.

- Monday is setting up to have the greatest risk for severe storms
  that could be capable of tornadoes. Be weather aware on Monday!

&&

.DISCUSSION...
Issued at 230 PM CDT Fri May 15 2026

19Z water vapor imagery showed the mean westerlies across the
northern tier of the country with an upper low north of MN and
another north of WA. This pattern favored a more zonal flow over the
central plains with little evidence of shortwave energy immediately
upstream. Surface obs placed an area of low pressure of the OK/TX
panhandles with an inverted trough extending north through north
central KS and into eastern NEB. The 18Z RAOB from Topeka showed
there was still a substantial CAP to any surface parcels.

Severe potential for this evening looks to be tied to convection
developing over southeast NEB along the inverted trough axis. There
is a moderately unstable airmass over the forecast area with latest
SPC analysis showing around 3000 J/kg of MUCAPE. The strong
inhibition noted on the 18Z sounding is forecast to weaken as the
airmass continues to heat up through 6pm but not completely go away.
So with the lack of shortwave energy noted in water vapor, it may be
the convergence along the boundary that sets off convection. Bulk
shear is pretty modest at around 30KT. This suggests that if storms
form near the state line they may be quick to merge with nearby
storms with mainly a wind and hail risk. Latest CAMs have trended
towards keeping much of the convective activity north of the state
line though, and after about 9pm the inhibition is forecast to
increase as the boundary layer begins to stabilize. So there may be a
small window from 7 to 11pm when storms may pose a threat. Overnight
there is an increasing signal for an MCS to move out of eastern NEB
and IA. With the low level jet veering to the west southwest, the
track of any MCS is more likely to be into MO. So there is a risk
for severe storms this evening, but latest analysis points to the
risk being relatively small.

Saturday and Sunday are expected to be similar setups to today with
a hot and humid airmass providing plentiful instability for storms,
but with the better dynamics remaining mainly west of the forecast
area and some modest inhibition through peak heating. This would
create a conditional risk for severe weather tied to whether storms
can develop. One thing to keep an eye on is the GFS wanting to
surge the dryline into north central KS Sunday afternoon. This could
provide a focus for storm formation during the late afternoon and
evening.

Monday is shaping up to the the most dangerous day of the next
several with models in reasonable agreement bringing a shortwave out
of the southern Rockies with a slight negative tilt to it. This is
progged to force a cold front into a very unstable environment with
a very good wind profile for supercell storms. If storms can remain
discrete there will be a real risk for tornadoes. 12Z NAM/GFS want
to erode any inhibition away early in the afternoon with storms
blowing up along the boundary by mid afternoon. Will have to wait to
get a better idea of storm mode for Monday, but the combination of
instability, lift and forcing are enough that everyone will need to
be alert to the weather Monday.

The 12Z model guidance is in pretty good agreement with the synoptic
pattern through Tuesday and show the frontal boundary exiting the
forecast area Tuesday morning. This should shift any severe risk to
the southeast of the area for Tuesday afternoon. The NBM shows small
spreads in temps through Monday and the 12Z operational progs of 925
and 850MB temps support the initialization from the NBM, so have not
changed the temp forecast much. There is good confidence in a hot
and humid airmass sticking around through the weekend. Tuesday and
Wednesday should see a break from the heat and storms chances as
surface ridging moves through the plains. There are some slight
chance POPs in the forecast for Thursday and Friday as southerly
return flow redevelops. This is a low confidence forecast since
models don`t really show strong shortwave activity or a strong surge
of low level moisture to destabilize the atmosphere.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 625 PM CDT Fri May 15 2026

Still thinking TS chances are favored to remain well north of
terminals closer to the KS/NE border and north for this evening. CAMs
are hinting at the possibility of showery activity coming from
southeast KS, which could briefly impact Topeka sites Saturday
morning if that comes to fruition, but confidence is too low to
include for now. Otherwise, south/southeast winds should stay up
around 10 kts for a bit this evening before diminishing slightly and
then picking back up Saturday morning. Opted to keep mention of LLWS
tonight out of TAFs despite an increasing LLJ to 35-40 kts, mainly
due to soundings showing a gradual increase with height in the lowest
2kft, leading to more of a low-level turbulence setup.

&&

.CLIMATE...
Issued at 230 PM CDT Fri May 15 2026

Record High Temperature

Saturday May 16
                 Record (Year)           Forecast
Topeka           95 (1931)               91
Concordia        93 (2019)               93

Sunday May 17
                 Record (Year)           Forecast
Topeka           92 (1907)               90
Concordia        96 (1996)               97

Monday May 18
                 Record (Year)           Forecast
Topeka           94 (1975)               93
Concordia        94 (1967, 1988)         94


Record Warm Low Temperature

Sunday May 17
                 Record (Year)  Forecast
Topeka           73 (1996)  68
Concordia        68 (1902, 1906)  67

Monday May 18
                 Record (Year)  Forecast
Topeka           71 (1911)  73
Concordia        72 (1911)  69

&&

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

&&

$$

DISCUSSION...Wolters
AVIATION...Picha
CLIMATE...Drake/Wolters