121
FXUS63 KTOP 182343
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
643 PM CDT Fri Jul 18 2025

.KEY MESSAGES...

- Confidence is increasing in a prolonged period of hot weather
  for the region.

- An Extreme Heat Warning goes into effect for parts of the area
  Saturday, with a Watch for the remained of the area beginning
  Monday.

- Isolated to widely scattered showers and storms are expected
  through tonight. Next week looks dry with little chance for
  meaningful rain.

&&

.DISCUSSION...
Issued at 245 PM CDT Fri Jul 18 2025

19Z water vapor imagery showed the mean westerlies along the
US/Canadian border while upper ridging extended from the
southeastern US into the southern Rockies. Surface obs showed
low pressure along the lee of the central Rockies with high
pressure to the south and east of the forecast area.

Confidence in a prolonged period of hot weather is increasing and
have gone ahead and issued an Extreme Heat Warning for the southern
two thirds of the forecast area beginning Saturday afternoon. The
warning is a function of the duration of the heat more than the
actual forecast values of the heat index, which looks to be around
105 degrees for the next several days. These indices are most likely
along and south of the KS river while the potential for convective
outflow coming out of NEB brings some uncertainty to the temp
forecast for the northern counties. There is a pretty good consensus
among the ensembles for the upper ridge to amplify over the gulf
coast and retrograde towards the central plains through the first
half of next week. With this in mind have issued an Extreme Heat
Watch for the northern counties beginning Monday. Cluster analysis
of the 00Z ensembles showed little difference from the mean over the
central plains with anomalously high 500MB heights. So everything is
pointing to an extended period of heat. Spreads in the ensemble
temps start to increase by Thursday indicative of lower
predictability. So this is why I haven`t gone with the headlines
through the whole week. Obviously the warning will be extended if
the forecast remains on track in the coming days. Thanks to ICT, EAX
and SGF for the collaboration with the headlines.

As far as precip chances go, a remnant vort max is drifting across
central KS this afternoon. This feature may spark some isolated
convection through peak heating. Models show this feature shearing
out so I don`t anticipate showers and storms lingering much past 9
pm. There is a signal for an MCS coming out of the northern plains.
But the 12Z CAMs have trended to keep this northeast of the forecast
area with maybe some isolated to widely scattered showers developing
overnight within a warm air advection pattern. After that precip
chances become pretty conditional with upper ridging becoming more
dominant and synoptic scale forcing remaining north of the area.
Models even show 700MB temps warming to between +12C and +14C. The
NBM has some slight chance POPs along the NEB state line for
anything rounding the periphery of the upper ridge. This doesn`t
seem out of place for now, but by Monday hot and dry weather looks
like a good bet.

The only changes made to the NBM temps was to dial back highs a
degree or two next week and come down from the multiple days of
103. The forecast still calls for multiple 100 degree days but the
NBM looks like it is closer to the 75th percentile of the ensembles.
So the NBM may be a little to aggressive given the center of the
upper ridge is progged to be displaced east and south of the
forecast area.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 632 PM CDT Fri Jul 18 2025

A few showers and isolated thunderstorms last through about
02-03Z this evening as an MCV passes across portions of the
area. Went with VCTS mention as showers and thunderstorms are
expected to be brief if they do impact the terminals directly.
KMHK may end up being the most impacted terminal over the next
few hours. Overnight, clearing should begin to take place as the
MCV features passes east of the region. A moderately strong LLJ
sets up overnight mainly WSW of the terminals. Again, KMHK may
have see the strongest low-level winds set up. Still appears to
be marginal based on surface winds expected to remain partially
mixed. By early morning there may be a chance for a few showers
and thunderstorms to enter the area from the north as an MCS
works through Nebraska into Iowa but most impacts from this
system are expected to remain northeast of the terminals.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
Extreme Heat Watch from Monday afternoon through Wednesday
evening for KSZ008-KSZ009-KSZ010-KSZ011-KSZ012-KSZ020-KSZ024.
Extreme Heat Warning from noon Saturday to 7 PM CDT Wednesday
for KSZ021-KSZ022-KSZ023-KSZ026-KSZ034-KSZ035-KSZ036-KSZ037-
KSZ038-KSZ039-KSZ040-KSZ054-KSZ055-KSZ056-KSZ058-KSZ059.

&&

$$

DISCUSSION...Gargan
AVIATION...Drake