627
FXUS63 KDDC 171600
AFDDDC

Area Forecast Discussion
National Weather Service Dodge City KS
1100 AM CDT Tue Sep 17 2024

.KEY MESSAGES...

- Marginal Risk (Level 1 of 5) of severe storms this evening
  mainly west of Highway 283 to the Colorado line, however most
  storm will remain sub-severe.

- Overall precipitation amounts expected to be on the low side
  with most areas 20 to 30% chance of 1/4" of new rainfall.

- Eyes turn to Friday Night and especially late Saturday and
  Saturday Night as models are trending toward a heavier
  precipitation potential with a stronger storm poised for
  Kansas with a cold front involved.

&&

.DISCUSSION...
Issued at 357 AM CDT Tue Sep 17 2024

The remnants of last night`s convective episode across the northern
portion of the NWS DDC forecast area continued to slowly decay as it
moved into central Kansas as of 08Z. The remainder of the day will
be mostly clear in its wake and temperatures are forecast to rise
well into the upper 80s, topping out in the lower 90s much of
southwest Kansas.  The large upper level low out west will lift out
across the Rockies and adjacent Northern High Plains later today and
tonight. Upper level jet streak forcing for ascent tied to this
system will overspread western Kansas this evening, favoring
numerous shower and thunderstorm development within the warm
conveyor belt airstream of this mid-latitude cyclone. Overall
instability and moisture will not be all that great with HREF mean
SBCAPE only 300-700 J/kg out ahead of the developing broken line of
storms this evening. As a result, only marginal severe storms are
expected across our forecast area, and this will be confined to
areas west of Highway 283 only until a couple hours or so after
sunset.

As we head deeper into the night, the upper low will continue
to pull north-northeastward, farther away from southwest Kansas,
which will result in decreased forcing for ascent, and this tied
with nocturnal boundary layer cooling will lead to an overall
decrease in convective activity after midnight tonight. Latest 00Z
run of the HREF shows 0.25" rainfall probability of exceedance only
in the 20 to 35% range, but as we saw last night in western Trego
County, it only takes a few storms to train over one small area to
result in local excessive rainfall. The probability of this
happening again is quite low, as cloud-bearing winds will be
stronger and we should see a fairly steady progression of showers
and storms to the east versus last night.

We will see a break in thunderstorm chances Wednesday and Thursday
with chances increasing again Friday as the next storm system
approaches. The global models continue to slow this weekend storm
system down, focusing now on Saturday-Saturday Night for our NWS DDC
forecast area for widespread thunderstorm activity.

Taking a look at the last three runs of the 100-member Grand
Ensemble of ECMWF, GEFS, and Canadian ensemble systems, there is a
noticeable shift south in the 24-hr QPF fields. The latest 00Z run
now has 75th percentile (1-in-4 chance) QPF of 0.50" or greater
encompassing much of the DDC forecast area, including DDC at 0.64".
There is still quite a bit of time for the heavy precipitation zone
with the Saturday-Saturday Night storm to shift even farther south.
The ECMWF Ensemble system is the most favorable for much of our area
with over an inch in the 75th percentile QPF field from Dodge City
to Hays. A farther south track of the storm aimed more toward
Kansas, better/deeper moisture profile, and a rather strong
frontogenetic zone will all be much favorable contributors to a
potential heavy rain event, so keep checking back for updates
regarding the weekend forecast.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1111 AM CDT Tue Sep 17 2024

VFR is expected through TAF pd. A line of storms is expected to form
across Colorado and march eastward into Kansas by mid to late evening.
Have the highest confidence of terminal impact at KGCK and KHYS,
with lower confidence for KDDC and possibly KLBL. Timing of the storms
looks to be in the 03Z-06Z time frame. +TSRA cannot be ruled out,
in particular for KGCK and the storms will likely be the most robust.
Outflow winds of 50+ kt may be possible with most severe of storms.
Confidence is a little low right now to insert in the TAFs of this
impact, but will continue to watch and amend if confidence increases
with the winds.

&&

.DDC WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Umscheid
AVIATION...Sugden