936
FXUS63 KGLD 300756
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
156 AM MDT Tue Apr 30 2024

.KEY MESSAGES...

- A marginal to slight risk for severe thunderstorms continues
  for areas east of Highway 25 on Wednesday afternoon and
  evening. However, confidence is low at this time due to
  uncertainty on the location of a warm front which will
  determine where storms will develop.

- Near critical fire weather conditions are possible Friday
  afternoon south of Interstate 70 and west of Highway 27.

- Near critical to potentially critical fire weather conditions
  are forecast Monday afternoon for locations generally west of
  Highway 27.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 220 PM MDT Mon Apr 29 2024

Latest surface analysis shows a warm front from the Nebraska
panhandle into northwest Kansas and a new lee trough developing
in northeast Colorado. At 500 mb, seeing zonal flow with some
weak embedded waves. Visible satellite imagery shows some
scattered CU across the area with strong surface heating.
However bases are at around 10kft so only the occasional virga
on radar. Tonight, expecting mostly clear skies with surface
winds turning towards the southeast and gradually increasing.
Low temperatures will be in the 40s to lower 50s.

Tuesday, shortwave trough rotating around the base of an upper
low in the northern Rockies will force a surface cold front
through the area in the morning. Winds will shift to the
northwest behind the front with gusts up to 35 mph in northwest
corner of the area (Yuma County) and 20-30 mph across the
remainder of the area. Afternoon relative humidity values of
less than 15% have a fairly high probability of occurring for
areas south of Interstate 70, but probabilities for wind gusts
of greater than 25 mph are very low, as most of the wind is in
the morning behind the front. So, not expecting any fire weather
concerns due to the lack of wind in the afternoon. Despite the
frontal passage, expecting high temperatures in the 70s to
around 80. Tuesday night may see an isolated shower or two in
the post frontal upslope regime into the higher terrain, but
not much forcing otherwise. Low temperatures will be in the 40s.

Wednesday, will start the day cloudy and cool with east to
northeast surface winds. May be some fog as well. Old frontal
boundary will start to return north as a warm front into south
central Kansas during the afternoon. Models not in very good
agreement on how far north the front will retreat. NAM in
particular keeps the front south of the area with cloudy, cool
conditions through the entire day. GFS a little further north
but most of the area still capped, particularly north of the
Interstate. All of this casts some doubt on severe potential
Wednesday afternoon. Nonetheless, SPC keeps the eastern area
outlooked with marginal to slight risks, assuming the warm front
is further north. Deep layer shear will be sufficient for severe
storms should that happen. Synoptic scale forcing will also be
rather nebulous in the afternoon, with a broad southwesterly
flow aloft ahead of a shortwave trough axis still over the
central Rockies. As that wave comes out Wednesday evening,
showers and isolated thunderstorms will increase in coverage,
with the associated surface cold front serving as a focus.
Models again are not in particularly good agreement for
Wednesday night either. ECMWF is much wetter compared to the GFS
with a swath of near 1" precipitation amounts along the front,
while the GFS shows up to a half inch, mainly in southwest
Nebraska. Either way, with the upper dynamics and front moving
through Wednesday night should see the best chance for rain in
the area. Temperatures on Wednesday will be highly dependent on
what happens with the warm front, but for now NBM shows 70s and
80s across the area, but the NAM is notably cooler, especially
north of Interstate 70 in Kansas and Nebraska, showing only 50s
and 60s for highs. Low temperatures Wednesday night will be
mostly in the 40s.

Upper trough axis will be moving through Thursday morning with
gusty northwest winds behind it. Both GFS and ECMWF show gusts
to around 40 mph in the morning, gradually diminishing through
the afternoon. Best chance for lingering showers will be in the
morning. Highs will be in the 60s. A bit skeptical of the NBM
shower chances Thursday night with lack of forcing and surface
winds remaining downslope. Both the GFS and ECMWF are dry
Thursday night. Low temperatures will range from the middle 30s
in western areas to the lower 40s in eastern areas. Some patchy
frost possible in eastern areas where vegetation is
susceptible, but about a week early for frost/freeze concerns in
western areas where typical last freeze dates are around May 7-
May 10.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
Issued at 154 AM MDT Tue Apr 30 2024

Upper level ridging over the area with low pressure centered in
vicinity of ID/WY/UT Friday morning will have the area under
southwesterly flow aloft. As the low pressure system progresses
eastward, a front will sweep through the area in the Friday evening-
Friday night timeframe, giving around a 30-50% chance for showers/
thunderstorms. Heading into the weekend, upper level ridging will
build back in with flow becoming increasingly zonal while the next
system comes into view off the west coast. Low pressure will skirt
south of the area, then east on Sunday, and with the low level
easterly upslope flow allowing for increased moisture into the area,
at least expect to see some increased cloud cover but also potential
for increased chances (up to around 20-25%) of showers/thunderstorms.

As mentioned in prior discussion, there continues to be significant
differences in guidance with regards to timing/placement of the
early week low pressure system. Taking a look at ensemble members
for 12Z Monday, placement of the upper low center ranges anywhere
from still off the west coast to over the Desert Southwest to
already encroaching on our area, with the jet streak working
into our CWA. If the low is situated across the Desert
Southwest/Four Corners region during the first half of the day
Monday as currently suggested by majority of the GEFS ensemble
members, could be looking at impactful weather day(s) for the
start of the work week with possible hazards of gusty southerly
to southwesterly winds, fire weather conditions, possible
blowing dust concerns, thunderstorm potential followed by a
frontal passage and wind shift to out of the north. Very low
confidence at present in the potential for an early week multi-
hazard event, so will continue to monitor for better consistency
in guidance as this timeframe comes into closer range.

For temperatures, looking at highs in the middle 60s to lower-
middle 70s Friday and Saturday before warming into the 70s
Sunday, and middle 70s to middle 80s Monday. For low
temperatures, the forecast calls for middle 30s to upper 40s
Saturday morning, low-mid 40s Sunday morning, middle 40s to
middle 50s Monday morning, and low 40s to low 50s Tuesday
morning.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 945 PM MDT Mon Apr 29 2024

KGLD...VFR conditions are expected through the period. A
southeast wind around 10kts at taf issuance will continue
through tonight. On Tuesday, south to southwest winds around
10kts in the morning quickly shift to the northwest by 15z,
gusting up to 30kts or so through much of the afternoon. After
22z, northerly winds around 11kts veer to the northeast at
similar speeds.

KMCK...VFR conditions are expected through the period. A
southeast wind around 10kts at taf issuance will continue
through tonight. On Tuesday, a light southwest wind around 13z
quickly shifts to the northwest by 16z-17z, gusting up to 30kts
or so through the afternoon. After 00z, a northwest wind around
10kts veers to the northeast at similar speeds.

&&

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

&&

$$

SHORT TERM...JN
LONG TERM...CC
AVIATION...99