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000
FXUS63 KGLD 220434
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
1034 PM MDT Sun Apr 21 2024

.KEY MESSAGES...

- Near to above average temperatures are forecast for the week.
  There could be daily small chances for rain/storms.

- Elevated fire weather conditions are possible Thursday in
  eastern Colorado.

- Chance for severe weather Thursday generally east of Highway
  283.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 130 PM MDT Sun Apr 21 2024

Shortwave ridge will build across the area this afternoon and
tonight with clearing skies. Southwest surface winds will
increase late this evening with developing pressure gradient
between departing high and deepening trough in Colorado. HREF
shows mean gusts across the area of 35-40 mph between 10 PM and
3 AM MDT, diminishing after that. Low temperatures will be in
the upper 30s to lower 40s.

Monday, upper trough moving through the northern plains will
push a cold front into the area during the afternoon, located
roughly Norton to Goodland to Flagler at 21z. Ahead of the
front, relative humidity will drop to 15% or less, but winds
will be lacking for critical fire weather conditions. HREF
suggests a few isolated showers/thunderstorms possible along the
front, but instability will be limited to just a few hundred
jules of CAPE, mostly behind the front, with increasing CIN by
00z. Other hires models, especially the NAMnest, show a few
isolated showers/storms persisting in the post frontal
environment through Monday evening with modest MUCAPE, but
confidence is low. Any precipitation should end by 06z across
the area. High temperatures will range from the middle 70s in
northern areas with an earlier frontal passage to lower 80s
ahead of the front with a later passage. Lows Monday night will
be in the upper 30s to lower 40s.

Tuesday will be partly sunny and cooler with highs in the 60s
to around 70. Weak wave embedded in zonal flow aloft combined
with surface upslope winds will combine to initiate scattered
showers on the higher terrain of eastern Colorado in the
afternoon. These showers will move across the area Tuesday
night. 12-hour mean precipitation amounts from the NBM show less
than 0.05 inches by 12z Wednesday morning. Low temperatures
Tuesday night will be in the upper 30s to lower 40s.

Wednesday, zonal flow persists during the day with shortwave
ridge moving through Wednesday night. Ahead of the ridge may see
a few showers/isolated thunderstorms with weak embedded wave
and southeasterly low level flow into the higher terrain.
Instability will be quite weak, mean CAPE values around 100
j/kg, but just enough to mention the possibility of thunder.
Mean precipitation amounts by Thursday morning are less than a
tenth of an inch. Highs will be in the upper 60s to lower 70s
and lows in the 40s. It will also be breezy, with NBM mean wind
gusts approaching 40 mph by late Wednesday morning, but then
diminishing late afternoon and evening. Humidity values remain
well above any fire weather thresholds with the cooler
temperatures and unfavorable southeast winds.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Issued at 111 PM MDT Sun Apr 21 2024

Over the past 24 hours, the GFS, ECMWF, and CMC-NH have started
agreeing a lot more about timing of the system on Thursday.
They now show a moderately strong upper-level trough moving
through the area Thursday evening/night. At 850 mb, all three
show a low pressure system moving across the area between 21Z
Thursday to 12Z Friday, suggesting another nocturnal event. SPC
has kept a 15% severe weather outlook for our eastern area for
this timeframe. There is good agreement that an 850 mb moist
conveyor belt will setup around Thursday 0-6Z, feeding Gulf
moisture into the eastern 1/3 to 2/3 of the CWA, and continue
until the cold front attached to the low moves through.
Confidence is increasing (~45%) for timing of this event; late
Thursday afternoon to Friday morning looks to bulk of the event.

This setup looks fairly similar to the event we had April 11th.
A dryline will form in the central CWA extending southward and
move east as the evening progress, firing storms as it does.
East of the dryline, moisture will be plentiful for storm growth
and to the west of the line, dry, breezy conditions are
expected.

There are PoPs ranging from 20-70+ covering nearly all of the CWA
Thursday night. However, much like APR 11 system, majority of the
precipitation will fall in the northern CWA.

There is a risk of brief elevated fire weather for portions of
Cheyenne county in Colorado. RH values look to drop near 20%
while southerly winds gust up to 25-30 kts. The dryline, once
again, will be the deciding factor to what potential hazards any
location could see. RH values have increased with this round of
guidance, significantly lowering the risk of fire weather
danger for Thursday.

Winds will generally be southerly, save for Friday when they
will be northwesterly behind the FROPA. Pressure changes with
this system do not seem to be as strong as what they were last
week, thus current confidence for High Wind is less than 10%.
Gusts seem to max out around 30-35 kts. The generally southerly
winds will allow us to keep temperatures a bit warmer overall.
Thursday is expected to see mid 70s to mid 80s. Friday through
Sunday will be a bit cooler with highs in the 70s to low 80s.
Overnight temperatures will be in the mid 40s to low 50s with a
few places seeing upper 30s Friday night.

A weak ridge looks to build in from the southeast Friday night
and Saturday morning which will clear out any remaining
precipitation. This happens just ahead of another low pressure
system that guidance is showing will impact the area around
Saturday night. Due to how far away the event is, climatology,
and forecast temperature trend, we cannot rule out snow showers
or severe weather moving over the area with this second system.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1030 PM MDT Sun Apr 21 2024

..Below Average Confidence in Wind Speed/Direction on Monday..

VFR conditions will rule through the TAF period at both
terminals.. with cloud cover confined to mid-upper level
ceilings (~12-22 KFT AGL). Isolated to scattered high-based
showers (perhaps a storm) are possible in vicinity of either
terminal Monday afternoon, though.. confidence in convective
development/coverage is low enough to preclude explicit mention
with the 06Z TAF issuance. Southerly winds will increase
overnight into Monday morning as the MSLP gradient tightens in
response to upstream pressure falls /lee cyclone development/ in
Colorado. The aforementioned lee cyclone will extend eastward
into/over western Kansas during the day on Monday.. in the form
of an inverted surface trough extending (roughly) from GLD-ADT-
MCK. Winds at both terminals will highly depend upon the precise
evolution of the cyclone and location/orientation of the
surface trough. As a result, confidence in wind speed and
direction is well below average during the day on Monday.

&&

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

&&

$$

SHORT TERM...KAK
LONG TERM...CA
AVIATION...Vincent