758
FXUS63 KGLD 161650
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
1050 AM MDT Mon Sep 16 2024

.KEY MESSAGES...

- Warm and windy conditions are forecast for today and Tuesday
  with highs generally around 90. Winds are forecast to gust to
  30-40 mph today and 35-50 mph tomorrow.

- Storms are possible during the afternoon/evening hours today
  and tomorrow, though tomorrow has the better chance (40-80%).
  Severe weather is possible tomorrow with gusts up to 65 mph
  possible.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 308 AM MDT Mon Sep 16 2024

The short term forecast remains active with strong winds the next
two days and chances for storms.

Early morning storms continue to impact eastern portions of the
area, largely driven by the presence of low/mid level moisture and
lower level convergence cause by the LLJ. Storms have been sub-
severe and the increase in winds saw earlier this evening has not
been occurring so the jet does not appear to be mixing down as
efficiently. These storms should leave the area around or shortly
before sunrise.

For the morning and early afternoon hours, skies are forecast to
initially clear off underneath southwest flow aloft and allow
temperatures to warm around 90. Meanwhile, the upper low/trough over
the Western CONUS is forecast to begin shifting slightly to the
east. This will tighten the height gradients over the area and allow
winds to strengthen to around 30 kts in the 850-700mb layer. With
the heating and mixing through the day, this will allow for surface
wind gusts up to 35-40 mph through the day.

Later in the afternoon and during the evening, the area will have
another chance for storms with lower pressure along the Front Range
creating a convergence zone along the Palmer divide as the southwest
flow brings in some mid-level moisture from the southwest. The low
level jet is forecast to develop again during the evening hours and
help carry storm chances east across the area. Coverage is currently
forecast to be isolated to scattered with the overall lack of
forcing and drier air in the lower levels. But similar to recent
days, will need to keep an eye for how much the jet enhances storm
development and maintenance. Storms should generally remain sub-
severe with gusts generally below 50 mph, but a storm or two could
produce a gust up to 60 mph. I`m more worried about a scenario
similar to yesterday evening where the jet may briefly mix down
before the inversion fully sets up. In short, expect another windy
evening. The rest of the night will see storm activity slowly taper
off and lows drop into the 60`s while winds remain somewhat elevated
around 15-20 mph as the upper trough moves closer to the area.

Tuesday, the upper low is forecast to move through the Rockies. This
will continue to tighten the height gradients with winds around 40
kts possible in the 850-700mb level. With clear skies to start,
ample mixing should occur and allow for surface wind gusts around 35
to 50 mph through the day. Temperatures are forecast to warm to
around 90 again no warm air advection as the system nears.
Widespread/concentrated blowing dust is not expected as local
research suggests the winds are just weak enough with 2km lapse
rates to steep to contain any dust. However, any recently plowed
field or source region for dust may see localized visibility
reductions.

Later Tuesday afternoon and into the evening, the upper trough and
surface low pressure system are forecast to swing through the area.
With the upper southwest flow bringing in moisture and the brief
southeasterly surface flow forecast to bring in some moisture,
storms are expected to fire up along the Palmer Divide and then
track east through the area. As long as storms don`t gust out and
surface winds ahead of the line of storms maintain a more
southeasterly orientation, there should be enough moisture and lift
to have decent storms move through as a line or multiple clusters.
This will give the area a good chance for rain with POPs generally
in the 40-80% range. Severe storms will be possible more with the
earlier storms in Eastern Colorado and counties just to the east
when there is a higher chance of storms being organized or discreet.
Overall instability is forecast to be marginal (MUCAPE around 1500
J/KG) with effective shear low to generally unidirectional winds.
However, the overall strong flow and roughly linear mode will make
it possible to see a few gusts to 65-70 mph. As a side note,
previous events have shown that winds tend to be sub-severe when the
overall surface flow is strong until near or after sunset. In short,
a chance for marginally severe storms moving across the area is
possible.

Tuesday night should see storms exit the area around or shortly
after 2-3am central time. As the upper trough continues to lift
north, the surface gradient is forecast to weaken as the main low
pressure center lifts north as well. As long as the inversion sets
up, the stronger winds aloft should also decouple through the night
and allow winds to lower getting close to sunrise. This should allow
for lows in the 50`s for any locales that have storms clear out
earlier in the night.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Issued at 136 AM MDT Mon Sep 16 2024

The latest runs of the GFS/ECMWF both show with the passage of the
system for Tuesday night, upper ridge re-amplifies over the Plains
region setting up SW flow aloft for the two day period. At the
surface, there will be a low over eastern Colorado that meanders
eastward on Wednesday w/ a front extending over northern tier zones.
Guidance on Thursday sets up another low over Colorado on Thursday
as well, but this system will not push east until Friday.

So with SW flow aloft for Wed/Thu and a southerly flow during the
daytime hours, the region will see near to above normal warmth each
day. The position of the low each day will dry conditions for
portions of the area each afternoon. RH values Wednesday will range
in the mid teens to lower 20s from Highway 27 and west. On Thursday,
mid and upper teens spread further east towards the Highway 25
corridor. As a result, increased fire wx conditions will ensue.
Winds each day remain below criteria(25 mph).

For Friday on through Sunday, both models will bring the broad
shortwave over the western portion of the country into the Rockies
and lifting E/NE by Sunday night. There is some inconsistency as to
the timing/placement of the upper system which will affect QPF
potential/duration. A 700mb trough/low will traverse the CWA during
this time, interacting with a cold front to trigger rw/trw. High
pressure to the east will stall the eastward advance of this system.
This will allow for decent precip chances Fri(20-30%), Fri night(40-
60%), Sat(30-40%), decreasing to 20-30% Saturday night as the system
begins to lift out of the area. Lingering 15% chances in the far
northeast early Sunday morning before dry wx ensues late Sunday
onward. While the potential for strong storms is possible as the
front moves through the area, will wait to see how the system
progresses to highlight further. System track favors the highest QPF
potential in the E/NE zones where WPC QPF has over an inch possible.

For temps, looking for highs on Wednesday to range in the 80s, with
a mix of 80s and 90s on Thursday. On Friday as a cold front begins
to work into the area, a wide range from the upper 70s to the upper
80s is expected, warmest along/east of Highway 25. For the upcoming
weekend into next Monday, a cool down with 70s expected. Overnight
lows will transition from the 50s and 60s Wednesday and Thursday
nights, to a mix of 40s to lower 50s(east) from Saturday night
onward.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1050 AM MDT Mon Sep 16 2024

KGLD...VFR conditions are expected through the period. Southerly
winds gusting to 35kts are anticipated from taf issuance through
sunset, subsiding a bit but still gusty overnight through
sunrise Tuesday morning. Southerly winds quickly increase after
sunrise with gusts up to 35kts. Presently, showers/thunderstorms
will be possible near/over the terminal in the 23z-01z
timeframe. The primary hazard will be strong wind gusts,
potentially severe, along with blowing dust that could produce
significant reductions in visibility. Should this occur, sub VFR
cigs and vis would be likely.

KMCK...VFR conditions are expected through the period. Southerly
winds gusting up to 35kts are anticipated from taf issuance
through sunset with winds subsiding some through sunrise Tuesday
morning. Southerly winds quickly increase after sunrise with
gusts up to 35kts. Presently, showers/thunderstorms will be
possible near/over the terminal in the 01z-02z timeframe with
gusty outflow winds the primary hazard.

&&

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

&&

$$

SHORT TERM...KAK
LONG TERM...JN
AVIATION...99