299
FXUS63 KGLD 181712
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
1112 AM MDT Wed Sep 18 2024

.KEY MESSAGES...

- Critical fire weather conditions are possible over portions of
  the area on Friday, mainly along/west of Hwy 25 where breezy
  southwest winds may develop during the mid-late afternoon.

- Showers and thunderstorms will develop over much, or all, of
  the Tri-State area this weekend as a potent upper level low
  tracks eastward across the Rockies and Central Plains. Severe
  thunderstorms, heavy rainfall and isolated flash flooding are
  possible, mainly Saturday afternoon through Sunday morning.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 400 AM MDT Wed Sep 18 2024

Overview: A modest upper level ridge over the Southern Plains
will amplify and extend northward over the Central Plains
through the remainder of the work week. Meanwhile, a potent
upper level low.. presently situated offshore the Oregon coast..
will dig S-SSE along the CA coast (today-tonight), stall invof
central-southern CA (Thu-Thu night), then track E-ENE toward the
4-Corners (Fri-Fri night).

Today-Tonight: Subsidence in the wake of a progressive
shortwave (lifting northeastward into central Nebraska at 09Z
this morning) will foster a west-east clearing trend this
morning. Expect sunny skies, dry conditions and above-average
temps this afternoon (albeit several degrees cooler than
yesterday). While light S-SW or variable winds may prevail in
eastern CO (invof a weak, broad lee trough).. forecast soundings
suggest that downward momentum transport assoc/w deep vertical
mixing may yield 15-25 mph SW winds over much of northwest KS
and southwest NE this afternoon.

Thursday: Clear skies and unimpeded insolation assoc/w the
amplifying upper ridge over the region will foster dry
conditions and above average temperatures, though.. a short
period of breezy (15-20 mph) N winds and modest cold advection
(assoc/w the passage of a weak surface to 850 mb /SFC-H85/
trough Thursday morning) may temper highs to some degree. Expect
light/variable winds and temperatures ranging from ~80-90F
during the afternoon, coolest in northeast CO.

Friday: Upper level flow will back to the SW and strengthen
late Fri-Fri night.. as the aforementioned upper low progresses
east toward the 4-Corners. Forecast soundings continue to
suggest that deep vertical mixing and strengthening mid-level
flow may yield breezy (20-35 mph) SW winds and exceptionally dry
conditions over portions of the area late Fri afternoon..
mainly along/west of Highway 25, where critical fire weather
conditions are possible. Isolated high-based convection cannot
entirely be ruled south of I-70 during the late afternoon, when
and where marginal high-based instability (~100-250 J/kg MLCAPE)
may be present invof a modest low-level convergence zone /
dryline. At present, guidance suggests that diurnal convection
will be relegated south and east of the Goodland CWA. Outflow
/mesohigh development/ emanating from upstream convection.. in
this case, southeast CO and southwest KS would be `upstream`..
could (potentially) affect wind/temps in southern portions of
the area Friday afternoon.. depending on upstream convective
coverage.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Issued at 201 AM MDT Wed Sep 18 2024

The long-term looks to start off active and become more docile
through early next week.

Saturday morning, a well organized low pressure system will be
near the Four Corners Region and rapidly moving northeast into
the High Plains. Throughout Friday night, a moderately strong
850 mb LLJ will set up and move additional moisture into the
region. The additional moisture will keep temperatures from
cooling off too much Saturday morning, but will limit day time
heating. High temperatures are expected to be in the upper 70s
to low 80s across the region, but if the clouds break, expect
warmer temperatures. The combination of warm, moist air with the
low pressure system (and associated fronts) will fire off
storms, likely in the afternoon and evening hours. Models are
fairly consistent will widespread precipitation being expected.
Deep layer shear during this event looks to increase the
potential for severe weather (~5-10%), but instability is
marginal. There is also a small (<10%) chance winds ahead of the
storms could gust around 30-35 kts in eastern Colorado
producing blowing dust. If there is a clearing of the clouds and
the winds are able to pick up, localized blowing dust could
occur, otherwise blowing dust is not expected to be a major
hazard.

As the low moves farther into the CWA, winds will become
northwesterly and start cooling off the area. High temperatures
on Sunday look to remain largely in the upper 60s, and
potentially cooler depending on the efficiency of the CAA. The
low pressure system will take until Sunday night to move out of
the area, giving the area increased PoPs through Sunday evening.

Once the low moves out, northwesterly flow is expected to
dominate the High Plains through the remainder of the period.
This will keep high temperatures in the mid 70s and lows in the
40s to low 50s for the rest of the period. As is typical in
northwesterly flow on the High Plains, shortwaves are bound to
occur and could bring isolated to scattered showers and storms
into the area. Monday through Wednesday, no organized systems
seem likely, just the potential shortwave showers.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1110 AM MDT Wed Sep 18 2024

Low clouds will persist for another hour or two at KMCK, then
clearing. Otherwise, VFR expected to prevail at both KMCK and
KGLD through the TAF period. Expect a wind shift to the north at
both terminals Thursday morning with a cold front.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.

&&

$$

SHORT TERM...Vincent
LONG TERM...CA
AVIATION...024