920
FXUS63 KDDC 241051
AFDDDC

Area Forecast Discussion
National Weather Service Dodge City KS
551 AM CDT Mon Jun 24 2024

.KEY MESSAGES...

- Heat Advisory remains in effect for up to 105F Heat Index this
  afternoon from roughly Wakeeney through Pratt to Medicine
  Lodge.

- Heat Advisory has been issued for Tuesday afternoon over a
  larger area, including areas as far west as Liberal to Dodge
  City line. The Red Hills area of Comanche-Barber County may
  even flirt with 110F Heat Index Tuesday.

- A wetter pattern is now expected beginning late Wednesday,
  perhaps lasting all the way through Saturday Night, as
  multiple nighttime thunderstorm systems will likely roll
  east/southeast across our region. The latest ECMWF Ensemble
  system 50th percentile QPF is up to an inch of rain for this
  period, which is pretty high for an ensemble system median.

&&

.DISCUSSION...
Issued at 407 AM CDT Mon Jun 24 2024

Hot temperatures will be the continuing theme in the forecast today
and Tuesday. The overnight water vapor imagery and RAP analysis
showed a fairly low amplitude pattern with the main polar branch of
the westerlies up north in its climatological latitude near the
Canada line. A southern branch jet of lesser magnitude/influence
extended across the Great Basin and Colorado on the northern
periphery of the summer subtropical high which extended across the
Desert Southwest east across Texas.

There aren`t any major surprises or changes in the forecast through
Tuesday, as all models are locked in with the heat dome expanding
its influence across the central CONUS. A fairly deep leeside trough
will exist across eastern Colorado both this afternoon and Tuesday
afternoon. The MSLP gradient east of the leeside trough will lead to
breezy south/southwest winds today to the tune of 15 to 25 mph
sustained winds with higher gusts.

The dewpoint and resulting Heat Index forecast is a bit more
challenging than the actual air temperature forecast, given
differing model solutions on the magnitude of moisture mix-out late
in the afternoon, especially east of Highway 283. The 12Z run of the
HREF, using 50th percentile, was a bit too bullish on the mixing out
of dewpoints into the mid-upper 50s all the way east into central
and south central Kansas, based on late afternoon observations
Sunday. That said, today will be windier, offering a better chance
for dewpoints to mix out into the upper 50s to around 60, even as
far east as a Hays to Pratt to Medicine Lodge line. Regardless, as
afternoon temperatures reach lower 100s, resulting heat index should
still approach 105 degrees, thus the going Heat Advisory (using 105F
threshold) still looks like a good forecast.

On Tuesday, 850mb +30C isotherm is expected to push even farther
east into central/south central Kansas, which will support
widespread afternoon temperatures in the 102 to 105F range. Given
this magnitude of heat, just on the air temperature alone, we have
added Tuesday into a Heat Advisory and included more counties...as
far west as Liberal to Dodge City. The western edge of Tuesday`s
Heat Advisory follows fairly closely the 40% Probability of
exceeding 103F Heat Index off the 00Z run of the HREF.

The aforementioned weaker, southern branch of the upper level jet
will likely provide enough support for widely scattered storms this
evening, mainly northwest of our forecast area. HREF does have some
members of 35+ dBZ Composite Reflectivity clustered in our northern
area late tonight as some of the CAMs attempt to develop a small
MCS. The official forecast will carry some Slight Chance 20% POPs
north of roughly Garden City to La Crosse line. Severe storms are
unlikely given weak 0-6km AGL shear magnitude.

The HREF and global models show a better signal for more organized
convection late Tuesday into Tuesday Night focused mainly on central
and south central/southeastern Kansas, although latest SPC SWODY2
does bring a a 5% hail and wind area west to include areas east of a
Scott City to Meade line. A cold front will follow on Tuesday Night,
and this will bring a reprieve from the 100-degree heat as we enter
a more favorable MCS pattern.

Post-frontal moist upslope will develop across western Kansas Wed-
Wed Night, which will favor development of a strong/severe MCS. The
GEFS shows up to a 50% chance (using joint probs of 6hQPF > 0.02",
SBCAPE > 250, and 0-500mb bulk wind shear > 20 kts) of a MCS rolling
across western/central Kansas, including much of the DDC forecast
area. In fact, the 00z GEFS repeats this signal for Thursday Night,
Friday, and even Saturday Night. This is also reflected in latest
NBM POPs as we now have four straight nights of 30-50% POPs covering
at least half of the NWS DDC forecast area each night. For the
period Wednesday Night through Saturday Night, the 100-member Grand
Ensemble (combining all members from GEFS, ECMWF-Ens, and Canadian-
Ens) now has well over one-half inch total QPF for the 4 day period
with the ECMWF EPS leading the way with upwards of 1" total QPF
(50th percentile) cutting across the mid-section of our forecast
area including Garden City, Dodge City, and St. John. Obviously,
when dealing with summer convection, there will be local higher
amounts over the 4-day period should this pan out as forecast, and
if we use 90th percentile off the wetter ECMWF EPS, we could be
looking at quite a few areas over 2 inches of rainfall.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 549 AM CDT Mon Jun 24 2024

South winds will increase later in the morning as a leeside
trough strengthens across the High Plains of eastern Colorado.
Afternoon winds are expected to top out in the 16 to 20 knot
range sustained with gusts mid-upper 20s knots. VFR flight
category is expected to prevail through the period. There is
some increasing signal of a small thunderstorm cluster moving
across west central Kansas late tonight, however this 12Z
synoptic TAF will not include any mention of thunderstorms at
any of the terminals yet given low confidence of occurrence.

&&

.DDC WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 1 PM this afternoon to 8 PM CDT this
evening for KSZ030-031-046-065-066-081-090.
Heat Advisory from 1 PM to 8 PM CDT Tuesday for KSZ030-031-045-
046-064>066-077>081-086>090.

&&

$$

DISCUSSION...
AVIATION...Umscheid