570
FXUS63 KTOP 151711
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
1211 PM CDT Sun Sep 15 2024

.KEY MESSAGES...

- Temperatures 5 to 10 degrees above normal are forecast to
  continue through much of next week.

- Limited forcing may spark some hit or miss showers and storms
  across north central KS each of the next couple mornings.

- A more organized chance for rain is forecast for Friday and
  Saturday with chances for measurable precip around 55%.

&&

.DISCUSSION...
Issued at 309 AM CDT Sun Sep 15 2024

07Z water vapor imagery showed an upper ridge over the eastern Great
Lakes with an upper trough over the Pacific Northwest. The remnants
of last week`s tropical system remained over the south placing the
forecast area in a col or saddle point within the synoptic pattern.
Surface obs showed ridging over the Upper Midwest nosing into
northeast KS with troughing along the lee of the southern Rockies.

Through Tuesday forcing for precip is progged to remain rather
subtle. The main driver of POPs in this period is some isentropic
upglide within an area of weak mid level warm air advection. We can
see this by the development of some altocumulus over the last couple
hours. The RAP/NAM show the better lift and saturation remaining
over central KS with forecast soundings suggesting only a few
hundred J/kg of CAPE. The HRRR is not developing a lot of convection
with the lift, but other CAMs do show a storm or two developing. So
there could be a couple isolated updrafts develop through the mid-
morning hours and have continued with some slight chance POPs for
areas along and west of Abilene to Concordia. A similar setup is
forecast for the overnight hours Sunday and into Monday morning.
There is a little more consistent signal from the CAMs for elevated
showers and storms developing across north central KS, and have some
chance POPs as a result. Instability and shear are progged to remain
limited so potential for severe storms looks to be close to zero.
Warm weather is forecast to persist through the first part of the
work week as southerly low level winds become more predominate and
allow warm air to persist over the central plains. The forecast has
lows and highs generally 5 to 10 degrees above normal for the middle
of September.

There looks to be two opportunities for more organized precipitation
through the end the week. The first looks to be Tuesday night and
into Wednesday morning as a shortwave lifts from eastern CO into the
northern plains. This wave looks to pass mainly northwest of the
forecast area, but models are showing a similar idea for a line of
showers and storms forming to the west and moving into parts of
north central KS. Confidence is only so-so since the better dynamics
pass to the northwest of the area. But GFS and ECMWF ensembles show
a better than 50% chance for at least a hundredth of an inch. The
second opportunity looks to be late Friday and Saturday as models
show a deeper upper trough moving through the central Rockies. Here
the GFS and ECMWF ensembles have probabilities of measurable precip
between 70% and 90%. The chances for precipitation of at least a
half inch are around 40%. Have kept the initial grids from the
NBM which gives Likely POPs for Friday night. Well see if trends
from the blend follow what the ensemble data suggests. Temps
look to remain above normal through Thursday. Increase in clouds
and rain chances are expected to keep temperatures closer to
normal for Friday and Saturday.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1211 PM CDT Sun Sep 15 2024

Expecting mostly clear skies and 5-10 kt southerly winds to continue
through the day, as the current weak thunderstorms are dissipating
well south and west of KMHK. Overnight winds become weaker but a bit
more southeasterly. This could bring some low stratus or fog towards
KTOP and KFOE, but for now this appears most likely to stay to the
south and so will stay with a clear forecast.

&&

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

&&

$$

DISCUSSION...Wolters
AVIATION...Reese