000
FXUS63 KGLD 240501
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
1101 PM MDT Tue Apr 23 2024

.KEY MESSAGES...

- Potential multi-hazard event is forecast Thursday. Most of the
  area has a chance for severe weather with large hail being the
  main threat, although a few tornadoes will also be possible.
  The other potential hazards with the system include critical
  fire weather conditions, high winds and blowing dust, mainly
  south of Interstate 70 Thursday afternoon.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 215 PM MDT Tue Apr 23 2024

The central plains is under zonal flow aloft atop a ridge
centered over the southern plains. Moist southeasterly low level
winds tonight combined with a weak wave coming out of Colorado
will result in widely scattered light rain showers, mainly
during the overnight hours. Mean precipitation amounts from the
HREF and NBM are only a few hundredths of an inch. Low
temperatures will be in the upper 30s to lower 40s.

The ridge strengthens a bit on Wednesday but still looking at
mostly zonal flow. Another weak wave comes out of the Rockies
Wednesday night with another chance for scattered rain showers,
and perhaps an isolated thunderstorm. Precipitation amounts
range from a few hundredths in Colorado to around a tenth of an
inch in Norton and Graham counties in northwest Kansas. High
temperatures will be in the upper 60s to lower 70s and lows
Wednesday night in the 40s.

Thursday still on track to be the most active day of the period.
However, details on the timing and track of the upper system and
especially the location of the dry line still vary greatly from
model to model. The slowest and furthest west model is the
ECMWF, which shows the dry line in the far southwest corner of
the area, all the way in Colorado, and not moving much through
the evening. This would place much of the area in the moist,
unstable environment, but with the slower upper dynamics and
location of the dry line forcing would be limited for
convection and ECMWF precipitation amounts are not very
impressive. On the other hand, the GFS surges the dry line
northward Thursday afternoon, almost parallel to Interstate 70
by 00z. This scenario would bring a greater risk for severe
storms, as well as potentially critical fire weather and blowing
dust in the dry sector south of the Interstate. The NAM
solution is roughly between the GFS and ECMWF, not quite as far
north or east with the dry line compared to the GFS, but still
in northwest Kansas by 00z. Based on recent performance, will
lean into the GFS and NAM solutions. So, will introduce some
blowing dust south of Interstate 70 with favorable laps rates in
the 0-2km layer and wind gusts above 40 mph likely. Critical
fire weather conditions will also be possible, although the NBM
mean shows lowest humidity mainly in Colorado for a few hours.
The severe threat will be right along and north/east of the dry
line where a narrow corridor of SBCAPE of 1000-2000 j/kg will
develop (slightly higher in the NAM) and deep layer shear of
around 50 kts. This would favor both large hail and possibly a
few supercells capable of producing tornadoes given the well-
defined boundary with moist, easterly winds on the immediate
cool side. CIN increases rapidly away from the dry line, so not
sure how long any supercell will manage to stay surface based,
but assuming the dry line is moving will see the severe threat
move with it into eastern areas Thursday evening. Meanwhile,
wraparound moisture will begin to impact western areas with
additional thunderstorms and perhaps a continue low-end severe
threat for wind and hail. Westerly winds will also increase
through the night assuming the GFS timing, with gusts
approaching 40 mph.

Temperatures equally tricky on Thursday, dependent on location
of the dry line. Highs in the dry sector will be well into the
80s while east of the dry line in the moist sector temperatures
will be mainly in the 70s. Lows Thursday night will be in the
40s.

On Friday, should be dealing mainly with wraparound
precipitation as the upper low lifts into Nebraska. Best chances
will be north of Interstate 70 closest to the low. Winds may be
a concern as well, but it will depend on how fast the upper low
lifts out. GFS with the faster timing has less wind while the
ECMWF with the slower timing has more wind. The ECMWF has wind
gusts approaching 50 mph in the morning to early afternoon in
in the Kansas/Nebraska border area, but GFS only 30-40 mph. Not
expecting any severe storms with weak instability. Blowing dust
should not be an issue with the precipitation. High temperatures
will be in the 70s. Models want to bring in additional
showers/isolated thunderstorms Friday night in western areas with
another shortwave moving up in the southwest flow behind the
exiting system. Instability remains quite weak so no severe
storms expected with that activity. Low temperatures will be in
the 40s with diminishing winds.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Issued at 215 PM MDT Tue Apr 23 2024

Saturday, an upper trough will be located south of the Four Corners
region, with northwest flow over the CWA.  Through the course of the
day, the trough will lift to hte northeast, over portions of
southeastern Colorado and western Kansas.  Models show a closed low
developing on the lee side of the Rockies late Saturday
afternoon/evening.  For most of the area, there is a 40-70% chance
of showers and thunderstorms during the afternoon and evening hours
for the entire area.  A few thunderstorms may have the potential of
becoming strong to marginally severe, particularly in the
southeastern portion of the area.  Saturday night, there are a few
areas where temperatures are expected to fall into the mid-30s. This
may result in a few snowflakes mixing in with the rain, particularly
in Yuma and Kit Carson counties.

Sunday brings additional chances (20-50%) for showers through the
day as the system continues to lift northeast and moisture wraps
around the low.  Cooler air will move in over the area, with
expected highs currently forecast for the mid-50s in eastern
Colorado and extreme southwestern Nebraska to the mid-60s from
Tribune to Hill City.

A ridge will set up over the area around the beginning of next week.
Dry and warm conditions are expected, with highs in the 70s Monday,
and possibly 80s by Tuesday.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 1059 PM MDT Tue Apr 23 2024

VFR conditions are expected over the KGLD and KMCK terminals
through the 06Z TAF period. Light rain showers, possibly
remaining as virga, will move east between the terminals this
evening. Confidence is low that there will be any precipitation
over the terminals, hence the lack of mention in the TAFs. Winds
over KGLD will be increasing after sunrise Wednesday with
southerly winds gusting up to 25-30 kts from 17Z to 00Z.

&&

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

&&

$$

SHORT TERM...KAK
LONG TERM...99
AVIATION...KMK