227
FXUS63 KGLD 251645
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
1045 AM MDT Tue Jun 25 2024

.KEY MESSAGES...

- Another hot day today with triple digit temperatures
  forecasted area wide; Heat Advisory Graham and Norton
  counties.

- 30% chance of storms this afternoon mainly east of Highway 83;
  severe downbursts/microbursts the primary threats.

- Slightly cooler Wednesday and Thursday with better potential
  for rainfall; severe weather also possible.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 220 AM MDT Tue Jun 25 2024

Mainly zonal upper level flow is located across the area with a
departing shortwave across Gove county leading to a few lingering
showers and storms. The main story for the day continues to be the
triple digit heat and heat indices. Have decided to leave the
inherited Heat Advisory in place for Norton and Graham counties. A
boundary looks to be in place across eastern portions of the area
with drier air behind it; if this boundary does set up a bit further
south/east then the 105 heat index criteria may not be met as dew
points will be lower. Either way it will still be hot not only in
the Heat Advisory area but across the entire forecast area with
virtually the entire CWA forecasted to see triple digit heat.

Along the same boundary will be monitoring for thunderstorm
development mainly along east of a McCook to Leoti line. Similar to
Monday, pulsey summer time thunderstorms look to be the main concern
with severe downburst/microburst potential as inverted v soundings
will again be present across the area. Some blowing dust may
accompany the strongest downbursts and be localized in nature.
The threat for any hail looks to be fairly low due to the weak
flow resulting in weak shear across the area; also do have
concerns for residence time aloft in any updraft as well for
large hail to be a threat. Overall coverage is a bit tricky to
forecast in weakly forced setups as CAMS normally are not very
reliable; have opted to focus my highest pops along the above
mentioned boundary and where there is a noticeable increase in
700-500mb moisture.

Wednesday morning, fairly good consensus thus far with an increase
in 850mb moisture advecting in from the NW over mainly Yuma, Kit
Carson, Cheyenne and western portions of adjacent counties. Will
need to watch for fog/stratus potential around sunrise Wednesday,
have not introduced any fog wording into the forecast yet as I want
to monitor for any potential changing of location,  but did increase
sky coverage to account for this.

For the day Wednesday, a reprieve from the triple digit is currently
forecasted for the area with highs in the 90s. The surface high that
has been situated across the area leading to the hot
temperatures of late looks to get shunted to the south as a
potent trough from the Pacific Northwest influences the upper
level pattern. This will then open the area to be impacted from
shortwaves off of the Rockies; which is what the NAM, RAP and
GFS all currently suggest. Very high PWATS ranging from 1.6 to
1.9 inches look to be in place across the area with easterly
upslope flow in place as well. Forecast soundings across eastern
Colorado do support some large hail potential as well initially
before showers and storms grow upscale and move across the state
line. A caveat however.... is the ECMWF which is slower with
the NW trough shunting the surface high to the south out of the
area. If the surface high remains then subsidence remains
across the area virtually eliminating our precipitation
chances. Since the ECMWF is currently the outlier, confidence is
on the lower end of this occurring but does need to be
mentioned and this is the reasoning for keeping pops around 50%
and not increasing them.

Thursday, may see some stratus linger about for the good majority of
the day across the east so have stared trending high temperatures
down across that portion of the area. If the stratus is thick enough
and lingers all day (which the NAM suggests) it may be a struggle
for some locales to reach the 80s. Similar to Wednesday, another
wave moves off of the Rockies, this time the surface high will be
shunted south of the area which will favor shower and storm
potential across virtually the entire forecast area. At this time it
appears that large hail will be the primary hazard initially
before becoming a damaging wind/heavy rain threat as storms grow
upscale.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
Issued at 215 AM MDT Tue Jun 25 2024

Cold front will slip into the area Friday morning and stall out
just south or possibly in the southern part of the forecast
area by the time of peak heating and convective initiation
Friday afternoon. A fairly decent shortwave will be coming out
of Colorado to aid in ascent. While the front will undoubtedly
be the favored area for convection, the post frontal upslope
environment should also see fairly high precipitation chances
going into Friday night. Instability is modest at best,
generally 500-1000 j/kg, though deep layer shear is excellent
due to the directional component. Forecast soundings show a hot,
dry, deeply mixed environment, even post frontal, which should
yield a low-end marginal risk for severe wind gusts or hail.
High temperatures will be in the mid to upper 90s and lows in
the 60s.

Upper ridge strengthens over Texas for the weekend resulting in
southwesterly flow aloft over the central High Plains. Will see
weak perturbations rotate around the ridge resulting in
scattered thunderstorm chances both days. Chances on Saturday
may wait until Saturday night with fairly stable conditions
during the day, but with more typical afternoon and evening
chances on Sunday. In fact, models show a narrow corridor of
moderate instability Sunday afternoon straddling the Kansas and
Colorado border area along with deep layer shear of 40-50 kts.
That would support a severe risk, including supercells, if the
trend continues. High temperatures will be in the mid to upper
80s on Saturday and low 90s on Sunday, with lows in the 60s.

Upper pattern will be more or less the same on Monday, but
surface pattern shows more of a dry, southwest wind in most of
the area with the instability axis shifting eastward from Hays
into southwest Kansas. With another shortwave coming out of
Colorado in the afternoon and evening, storms chances will
continue. Would probably only see a marginal wind risk with
storms in the majority of the area with temperatures back into
the lower 100s and deeply mixed, inverted-v soundings, but
closer to the aforementioned instability in eastern areas could
see a hail threat with stronger storms. However, confidence in
those kind of details are low at this time range.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1045 AM MDT Tue Jun 25 2024

KGLD...VFR conditions are expected through the period. A
northerly wind gusting to 20kts at taf issuance will continue
this afternoon, subsiding below 10kts while veering to the
northeast overnight. Wednesday morning, east winds gusting up to
25kts are forecast.

KMCK...VFR conditions are currently forecast through the period.
A west wind up to 10kts at taf issuance will veer to the
northwest this afternoon, increasing a bit with gusts to 20kts
possible. Tonight, northerly winds around 10kts veer to the
northeast. Wednesday morning, winds veer to the east at speeds
around 12kts with a few higher gusts. Stratus and sub VFR cigs
are possible a few hours either side of 15z Wednesday.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Heat Advisory until 8 PM CDT this evening for KSZ004-016.
CO...None.
NE...None.

&&

$$

SHORT TERM...Trigg
LONG TERM...024
AVIATION...99