textproduct: Topeka

KEY MESSAGES

- A broken line of thunderstorms is expected to move east across the area this afternoon, exiting to the east around 8pm. Some of the thunderstorms could be severe.

- Cool and dry weather is forecast for the weekend. Those with a head start on gardens may want to protect tender vegetation with lows forecast to be in the 30s.

- Mild weather is forecast for next week with increasing precipitation chances towards the end of next week.

DISCUSSION

Issued at 1246 PM CDT Fri Apr 3 2026

1730Z water vapor imagery showed a closed upper low moving into NEB and SD. Surface obs placed a cold front from northeast KS into south central KS. Strong temperature advection was noted on both side of the front with a 30+ degree gradient across the 40 mile frontal zone.

Models are in good agreement with a broken line of thunderstorms moving across the forecast area with the front this afternoon. Much of this activity is expected to be exiting Anderson county between 7 and 8 pm. 17Z analysis shows the environment is already unstable with little to no inhibition. MLCAPE values are around 2000 J/kg with bulk shear of 40 to 50KT. Main question is whether storm mergers will be enough to disrupt updrafts and storm intensity, or if updrafts will be able to persist unimpeded. The motion of the front is forecast to be very close to the motion of a right moving supercell from forecast soundings. So it looks unlikely storms will develop and move off the boundary into the warm sector. Large hail and damaging winds look to be the main concerns, but there is a non- zero chance for a tornado with the effective SRH progged to be near 200 m2/s2. The CAMs seem to have a reasonable handle with the front and have used that as a first iteration for winds and temps into this evening.

Surface ridging with dry air is expected to move into the central plains tonight behind the front. This should bring an end to precip chances and set up nice weather for the weekend with plenty of sunshine and more spring like temps. Lows the next several days look to fall into the middle and lower 30s. So anyone who got a head start on their garden may want to take action to protect sensitive vegetation. Since it is still early April, we don't have any plans to go with frost or freeze headlines just yet.

Models show a northwest flow pattern changing to one with energy digging into the southwestern US for next week. Differing solutions have increased the spread in potential outcomes for next week as seen in the 00Z ensemble data. For Monday and Tuesday, A subtle shortwave is progged to move across the central plains on Tuesday with a return flow developing ahead of it. The GFS and ECMWF show some light QPF within the warm air advection pattern. But confidence is modest with these chances as a majority of the ensembles fail to develop measurable precip. Depending on temps there could be some light rain or snow if the moisture return is good enough for precip to develop. With QPF progs generally around a tenth of an inch impacts look to be minor and mainly across far northeast KS late Monday night or Tuesday morning. Better precip chances look to occur later in the week as a frontal boundary sags into the forecast area Thursday. A southwest flow aloft could bring perturbations over the frontal boundary with precip chances to end the week. There is a better signal from the ensembles for this scenario and think the likely POPs from the NBM are plausible. Temps are forecast to remain moderate with occasional frontal boundaries limiting a sustained warm up.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1149 AM CDT Fri Apr 3 2026

Only minor adjustments to the forecast expected as TS is already developing along the cold front. Will use CAMs as a first guess on timing. There could be some SHRA develop within the warm air advection pattern ahead of the front. But the FROPA should mark the end of precip chances. CIGS have been bouncing around 3KFT. This is likely to continue until the FROPA as well.

TOP WATCHES/WARNINGS/ADVISORIES

None.