Jamestown, Kansas Weather Forecast Discussion

373
FXUS63 KTOP 132313
AFDTOP
Area Forecast Discussion
National Weather Service Topeka KS
613 PM CDT Sat Sep 13 2025
.KEY MESSAGES...
- Shower and storm chances spread west to east Sunday. There
  could be a few strong storms across north central KS.
- Warm temps with an unsettled weather pattern is forecast next
  week. Rain and storms are possible (30-60%) Tuesday night into
  Thursday morning.
- A slight cool down is forecast to end the week.
&&
.DISCUSSION...
Issued at 228 PM CDT Sat Sep 13 2025
A broad upper level trough was seen on the 19Z water vapor
imagery with an upper ridge axis just southeast of the forecast
area. Surface obs put a broad area of low pressure to the north
of the forecast area centered near the NEB/SD state line. This
has kept southwesterly low level flow across eastern KS with
highs warming into the lower 90s.
There is not a lot of change to the going forecast with models still
showing the upper trough moving out into the central plains on
Sunday. Lapse rates out ahead of the upper trough continue to look
modest, but are forecast to improve marginally into the afternoon as
mid-level heights fall. Meanwhile the better bulk shear looks to be
confined to the upper trough. So the severe risk remains conditional
based on how much destablilzation can occur through the mid and high
clouds. The latest CAMs seem to suggest more robust convection
developing to the west of the forecast area underneath the trough
with storms approaching the western counties after sunset as the
boundary layer should be stabilizing. Weaker instability and shear
over northeast and east central Kansas make strong storms unlikely.
Think there should be enough sunshine across the eastern counties to
warm temps to around 90 Sunday afternoon. More cloud cover is
expected to keep temps in the middle and upper 80s across north
central KS.
The NAM is showing a conditionally unstable airmass Monday afternoon
as temps warm into the upper 80s with dewpoints still in the 60s.
With the shortwave progged to lift north, it doesn`t look like there
will be much forcing or lift to initiate convection. And the NBM
keeps POPs below 15 percent. But the NAM does hint at the potential
for an isolated shower or storm. So will need to keep an eye on
this.
Confidence in the forecast diminishes beyond Monday as models
continue to struggle with the overall synoptic pattern. The 12Z
guidance is now about 12hrs slower with shortwave energy moving
through the plains Tuesday showing better precip potential Tuesday
night into Wednesday. By Wednesday the models show little agreement
in how or where an upper low develops. Cluster analysis of the 00Z
ensembles show there are about three scenarios with equal
probabilities of occurring. With the lower predictability will
stick with the NBM. A potential boundary with the upper low over the
plains keeps some POPs in the forecast for Wednesday night and into
Thursday. Temps are forecast to cool slightly but there is a spread
of 6 to 9 degrees by Thursday so the forecast may be adjusted up or
down as models come into better agreement.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 612 PM CDT Sat Sep 13 2025
VFR at all TAF sites through the TAF period with southerly wind
and scattered high clouds. Thunderstorms are possible at the
very end of the TAF period, but confidence is too low at this
point in timing and placement to put into the TAF.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Wolters
AVIATION...Jones

NWS TOP Office Area Forecast Discussion