667
FXUS63 KDDC 200224
AFDDDC

Area Forecast Discussion
National Weather Service Dodge City KS
924 PM CDT Fri Jul 19 2024

.KEY MESSAGES...

- High confidence of a MCS moving through southwest Kansas with
  strong winds and brief heavy rain the main threats.

- Cooler than normal temperatures for highs will be the case
  through early next week.

- Off and on chances of storms will be in the forecast through
  next Tuesday.

&&

.UPDATE...
Issued at 923 PM CDT Fri Jul 19 2024

Both severe thunderstorm watches #555/#556 have been cancelled.
Storms have really struggled in marginal instability, and now
after sunset, that little instability is waning further. Have
done a major revamp of pops through sunrise Saturday,
diminishing them greatly through the very short term. Severe
thunderstorms currently entering far NW Kansas as of 920 pm CDT
will be watched by the incoming night shift, as 00z NAM/HRRR
agree they will make progress south into SW KS through 7 am
Saturday, when pops were increased again. Mesoanalysis indicates
a relative minimum in instability/lapse rates over much of NW
KS as of 9 pm, and it remains unclear if thunderstorms will be
able to survive this convective inhibition overnight. SPC severe
wind probabilities in the slight risk category remain in place
overnight for this possibility.

&&

.DISCUSSION...
Issued at 208 PM CDT Fri Jul 19 2024

19Z observations and upper air analysis show a developing MCS
situated from far northeast Colorado through central Nebraska with
our first severe report of wind northwest of Wray, Colorado.  This
line is in association with a 500 mb shortwave and we also have a
shortwave in north central Colorado which will also be a focus for
thunderstorm development this evening.  At the surface a 1009 mb low
in southeast Colorado has led to a stronger pressure gradient in
southwest Kansas thus we`ve had stronger south to southwest winds.

Tonight the advertised MCS will enter into our northwest zones
(Syracuse to Hays) roughly around 00Z and quickly move south and
east through the rest of our area through midnight.  HREF ensembles
have the greatest CAPE and theta e advection roughly along and west
of highway 83 between 8-11 pm and CAM models have latched on to the
stronger wind gusts in these areas where up to 70 mph is possible.
What CAMs have been struggling with is timing as the RAP has sped up
the prog of the line and the HRRR has slowed it down with the RRFS
being in the middle.  At this stage the RRFS is showing the best
timing which would put the highest impacts between 7-11 pm.  Hail
looks less of a threat with the large amounts of water loading in
the line plus the mode likely transitioned from supercell to squall
line that quarters would be the largest hail expected.  The
exception could be areas along and north of I-70 (WaKeeney to Hays)
where we still could have some supercelluar characteristics to the
storms.  After 10 pm the CAMs and HREF ensembles seem to agree the
instability should quickly diminish and the line will become more
general thunderstorms with pockets of heavy rain.  Ability of
reaching 0.25 inch or more of rain looks good as we have widespread
60-80% chances for almost all of southwest Kansas with the exception
of our far southeast and isolated 1 inch or more amounts are at 20-
30% for areas west of a Hays to Dodge City line.

Saturday the vort max should depart into central Oklahoma and DNVA
will lead to breaks in the clouds by late morning.  Post MCS
environment should be worked over much of the morning and combining
with northerly winds we should see storm chances low (>20%) through
the early afternoon.  Temperatures should be refreshing with highs
in the low 80s.  By late afternoon HREF ensembles and CAMs have a
developing vort max and increasing 700-850 frontogenesis roughly for
areas along and east of highway 83.  20-40% POPs are placed in these
areas as the storm mode should widely scattered in nature. Currently
there is no severe risk for Saturday but with CAPE values ~1000
J/kg, higher theta e values, and 0-6 km bulk shear values at ~30 kts
by 7 pm near Pratt...we may see a marginal risk introduced for some
isolated hail up to quarters and 60 mph gusts.

Early next week ensemble clusters show the upper air pattern
continuing to have a long wave trough over the central and eastern
CONUS with the 594 dm anticyclone situated over Nevada.  This will
keep northwest flow in place for early next week and 850 mb temps in
the 17-20 (C) range.  Mean high temperatures will be in the lower
80s for Monday and Tuesday.  With northwest flow in place we should
expect periodic shortwaves to move through the afternoon and evening
hours which will provide 20-30 POPs in southwest Kansas during this
time. Ensembles are trending in the day 5-7 range with the 594 dm
high moving eastward and spreading further into the Rockies. This
will both start to increase our temperatures and actively shut off
the rain chances.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 600 PM CDT Fri Jul 19 2024

A line of storms (MCS) will move through southwest Kansas
between 00-06Z. HYS will see this line move through first as we
could have VCTS as soon as 00Z. GCK and DDC will see the line
move through between 00-03Z and LBL at around 01-04Z.
Thunderstorms will contain heavy rain and gusty winds up to 50
kts which will lower surface visibilities to 4 SM or less. Most
of the thunderstorm activity should wrap up by 09Z. Otherwise we
should see VFR flight category for the rest of the time period.
Late in the day on Saturday after 21Z we could see some spotty
thunderstorms develop around GCK, DDC, and HYS.

&&

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

&&

$$

UPDATE...Turner
DISCUSSION...Tatro
AVIATION...Tatro