299
FXUS63 KGLD 151720
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
1120 AM MDT Mon Jul 15 2024

.KEY MESSAGES...

- Heat Advisory in effect for all but far eastern Colorado today
  from 9 AM to 8 PM MDT with heat indices up to 105 degrees.

- Potentially damaging wind gusts and small hail this evening.

- Cooler (less hot) temperatures and a bit better chance for
  rainfall for much of next week.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 404 AM MDT Mon Jul 15 2024

Weak mid-level disturbances will expand the surface trough east
across the Central Plains today while the upper high remains over
the Four Corners and over the Central and Southern High Plains. A
cold front will move south across the area from Nebraska beginning
around Noon MDT. This front does not seem to be very strong and may
create a brief wind shift as it moves through. One thing it may do
is help prime the atmosphere for storm development this afternoon
over Northwest Kansas ahead of the main round that will develop over
Eastern Colorado. The main window for storms to develop and/or enter
the western portions of the area is from 2 PM to 5 PM MDT with storm
coverage likely increasing into linear clusters as they move east.
Storms are currently expected to exit the eastern portions of the
area between Midnight and 6 AM Tuesday morning. Instability and
shear do look to be a bit better for storms today compared to the
what we had over the weekend. CAM soundings are consistent with
inverted-v soundings, indicating more of a wind threat with gusts up
to 60-70 mph possible. Small hail and heavy rain are also possible.
Localized blowing dust may occur over dry fields with visibility
reductions down to a few miles. With cloud cover expected to
increase from west to east this afternoon with the storm
development, it will be slightly cooler with highs ranging from 97
to 107 degrees. Heat Index values could be in the lower 90s to
around 105 degrees with the warmer values east of the Colorado
border. A Heat Advisory will be in effect for those east of the
Colorado border from 9 AM MDT/10 AM CDT to 8 PM MDT/9 PM CDT today.

On Tuesday an upper trough extending over the Plains from south of
the Hudson Bay in Canada and will flatten the upper ridge over the
Central Plains. Another cold front will sweep across the area during
the day with a stream of moisture trying to advect in from the
Atlantic and NE Canada. This will provide another chance for showers
and storms to impact the entire area and continue through Thursday
morning. SPC has placed the entire area in a Slight Risk for
tomorrow as large clusters of storms that could evolve into a more
organized line as it moves across extreme SW Nebraska and Northwest
Kansas during the evening hours. Damaging wind gusts and large hail
are the primary concerns; however, the hail threat will decrease as
we move in the evening and evolve into a line. Heavy rain is also a
concern with PWs favorable for flash flooding should storms begin to
train over the same area. Highs will be in the low to mid 90s with
overnight lows in the upper 50s to mid 60s.

On Wednesday the upper trough will push further south and amplify
the ridge over the Western CONUS placing the Tri-State area under NW
flow aloft. Some monsoonal moisture will interact with the moisture
stemming from the Atlantic to keep the rain and storm chances (up to
60%) continuing through the overnight hours. SPC has placed those
along and west of a Trenton to Leoti line into a Marginal Risk for
strong to damaging wind gusts associated with isolated to scattered
storms. High temperatures will be even cooler thanks to the cloud
cover with temperatures forecast to reach the low to mid 80s.
Overnight lows will be in the upper 50s to lower 60s.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Issued at 250 AM MDT Mon Jul 15 2024

The long-term looks to be a fairly active period. A 500mb high
pressure system will be sitting over the Four Corners area with a
trough over the Great Lakes. This will put us under generally
northwesterly flow the period. There are some weak ridges and
troughs that will keep the flow "interesting." GEFS is showing a
trough moving south, over the Great Plains during the weekend that
may force the high to retrograde more into the Great Basin area.
This would also bring in a more northerly flow and give upper level
support for convection.

In the lower-levels, the flow has returned to a more typical setup
for the High Plains, versus the guidance from 24 hours ago. We look
to start with southerly 850mb flow, which will pull moisture from
the SE CONUS and bring it into the CWA. Friday night, the GFS, CMC-
NH, ECMWF, and GEFS are all showing a low moving across the Northern
Plains and extending a cold front down through the CWA. This front
would likely be the best forcing mechanism in the period and could
fire numerous storms. Due to how far out this event is, specific
hazards are difficult to pinpoint, however guidance is suggesting we
could have a high precipitation event. Some of the parameters
supporting this include PWATS ranging from 1.2-1.7 inches, low-
levels becoming easily saturated, a weak/moderately unstable column,
and moderate shear. It would also not be surprising if this system
shifts to Saturday night if the high pressure retrograde is slower
than predicted.

The aforementioned low-level low pressure system looks to move in a
southeastern direction, which supports cooler temperatures with wrap
around moisture and northerly flow. This would work to increase non-
severe precipitation chances over the remainder weekend, but there
are a few reasons why this precipitation may not occur. For example,
we could get dry, southwesterly flow returning near the surface
which would cause more virga than precipitation.

On the very positive side, temperatures will be cooler! It looks
like the high temperatures will range from the upper 70s to lower
90s, with the warmest day being Friday. Overall, low temperatures
are stable, cooling into the upper 50s to mid 60s.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1118 AM MDT Mon Jul 15 2024

VFR expected to prevail at both KGLD and KMCK through the TAF
period. Scattered thunderstorms will develop late this
afternoon and move through the area tonight. Some storms may
produce gusty surface winds. However, uncertainty on coverage
precludes mentioning in the TAFs at this time.

&&

.CLIMATE...
Issued at 423 AM MDT Sun Jul 14 2024

Monday high temperature records
            Record  Year

Yuma        102     2006
Burlington  103     2000
Goodland    106     1925
Tribune     108     2000
Colby       108     1925
McCook      112     1925
Hill City   113     1934

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Heat Advisory until 8 PM MDT /9 PM CDT/ this evening for
     KSZ001>004-013>016-027>029-041-042.
CO...None.
NE...Heat Advisory until 8 PM MDT /9 PM CDT/ this evening for
     NEZ079>081.

&&

$$

SHORT TERM...KMK
LONG TERM...CA
AVIATION...024
CLIMATE...JTL