368
FXUS63 KGLD 231019
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
419 AM MDT Thu May 23 2024

.KEY MESSAGES...

- Isolated to scattered severe thunderstorms are forecast to
  develop Thursday afternoon and evening.

- Cold front moves through Thursday evening and night with more
  severe thunderstorms possible along the front across eastern
  counties and non thunderstorm wind gusts up to 50 mph across
  the western counties.

- For the holiday weekend, expecting a chance for storms both
  Saturday and Sunday, with some severe storms possible.

&&

.UPDATE...
Issued at 850 PM MDT Wed May 22 2024

For the overnight hours, latest 00z guidance is showing
increasing moisture in the 700-500mb layer moving across the
area from far eastern Colorado. Its anticipated that this
moisture source will work with 2km CAPE values around 500 J/kg
and limited CIN to at least support 20%-30% chances for showers
and thunderstorms mainly along the I-70 corridor (and
neighboring counties to the north) as well as Norton/Graham
counties. Presently, severe weather is not expected.

See Fire Weather section below for updated Red Flag Warning
Thursday.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 110 PM MDT Wed May 22 2024

Weak mid level ridging is present across the region currently with a
surface high in the lower levels; both of which are keeping the
skies virtually clear and the weather quiet. As we head into
the afternoon and evening a weak wave will move off of the Front
Range and onto the Plains. Winds will turn to the south and
begin advecting some moisture back into the area as a surface
trough develops; if everything can phase in time then some
isolated showers and storms may become a possibility around 01Z
across eastern Colorado and into NW Kansas. Little if any
rainfall is currently forecasted; will maintain with silent pops
due to concerns about the wave and the moisture return not
phasing. As the surface trough begins to deepen some tonight,
the southerly winds will become breezy with sustained winds
around 20 knots at times. This is forecast to help keep the
atmosphere mixed keeping overnight lows in the 40s to 50s.

The trough tomorrow looks to deepens into a surface low across
SW Kansas. Ahead of the low moisture will continue to return
from the Gulf of Mexico. A stout dryline will become present
through the afternoon which serve to be the focus for initiation
for the next round of severe thunderstorm potential. Confidence
is increasing in the dryline setting up near the Highway 25
corridor from Trenton through Leoti during the early to mid
afternoon. Discrete storms are forecast to develop along the
dryline with large hail around 2 inches in diameter damaging
winds being the primary threats as the NAM shows 2500+ j/kg of
MUCAPE with 40-45 knots of effective shear, steep lapse rate in
excess of 8 c/km and straight line hodographs. These hodographs
would support splitting of storms as well. If a discrete cell
can continue through 00Z (east of Highway 83) some tornado
threat may develop as the LLJ strengthens increasing the
streamwise vorticity. This scenario is seen in the 12Z NAMNEST
with elongating hodograph signature as well. I`ve strongly used
the NAM and NAMNEST for my forecast as these models have done
extremely will with convection and location of the dryline thus
far this spring. It is also interesting to note that the HRRR
has been consistently not initiating any storms along the
dryline, so that scenario is possible but at this time thinking
it is unlikely.

Into Thursday evening and night, a cold front then surges south
through the area. A second round of potentially severe storms may
occur along the cold front as well, as long as as the area remains
in the warm/moist sector (mainly east of Highway 25). Plentiful
MUCAPE and shear remains in place as more of a line/cluster pushes
south across the area. Damaging winds and hail will be the primary
threats. If any bowing segments occurs with the line then wind
driven hail may become more of a concern. Shower and storm
development back west across the front is a little more uncertain
due to the dry air in place; NAM and GFS both suggest 8-11 mb
pressure rises over 3 hours with and behind the front. Non
thunderstorm wind gusts around 50 mph looks to occur with this.
Blowing dust is also of limited concern due to the recent heavy
rains in the main dust source region of northeast Colorado.

Some fire spread potential will need to be monitored behind the dry
line as well as RH values look to fall into the low teens and deeply
mixed inverted v soundings look to help bring down wind gusts around
30 mph. After collaboration with surrounding offices, opted to hold
off on any fire weather highlights due to the continued spring
greenup and most importantly the recent rains. A portion of
western Cheyenne county Colorado also continues to lie in the
40th percentile ERC (Energy Release Component); however nothing
notable was being seen in calculating the GFDI with mid range
"Very High" fire spread numbers being seen which does lead me to
believe that the recent rains have helped the area mitigating
the burn ready fuels.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Issued at 419 AM MDT Thu May 23 2024

Storms, potentially severe, are forecast for the holiday weekend.
Heading into the next work week, a drying/warming trend is
anticipated as a ridge of high pressure builds overhead.

For Saturday, a somewhat similar setup to Thursday is forecast where
southwest portions of the area will experience fire weather
conditions west of the dryline while elsewhere could see the
potential for development of severe thunderstorms. Storms could
potentially form and progress eastward off the dryline in the
afternoon-evening favoring locations along/east of Hwy 83, but also
will want to monitor the potential for storms developing later in
the evening as some forcing could be provided by the 700-850 mb wave
swinging through possibly impacting more of the area. SPC has placed
areas generally along/east of Hwy 83 in a marginal (hazard level
1/5) risk for severe weather while along/east of Hwy 283 are in a
slight (hazard level 2/5) risk.

The main system remains forecast to move through in the Sunday-
Monday timeframe, providing 30-50% PoPs Sunday. Cooler temperatures
expected before a drying/warming trend at the start of the work week
with ridging building in. More storm chances return Tuesday-
Wednesday as embedded waves traverse through the flow.

For temperatures, middle 70s to upper 80s expected for highs on
Saturday, slightly cooler in the 70s Sunday, then warming again
Monday onward, with 80s for most of the area by Tuesday. Low
temperatures are forecast to be in the middle 40s to low-mid
50s.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 950 PM MDT Wed May 22 2024

KGLD...VFR conditions are expected through the period.
South-southeast winds of 12-15kts with some higher gusts are
anticipated from taf issuance through sunrise. From 12z-00z,
southerly winds will slowly veer to the southwest, gusting up to
30kts. After 01z, winds are currently forecast to quickly shift
to the northwest with gusts up to 35kts as a cold front moves
through. Presently, no precipitation is anticipated.

KMCK...VFR conditions are expected through the period. A
southeast wind up to 10kts is forecast from taf issuance through
13z. From 14z-00z, southerly winds gusting up to 30kts are
forecast. After 01z, winds are currently forecast to quickly
shift to the northwest with gusts up to 30kts as a cold front
moves through. At this time, confidence is too low to pinpoint
when/if the terminal would see showers/thunderstorms in the
vicinity or over the terminal. Presently, it appears the 23z-03z
timeframe would have the best chance based on the latest data.

&&

.FIRE WEATHER...
Issued at 850 PM MDT Wed May 22 2024

Recent coordination with our fire weather partners suggest the
continuance of Fire Weather Watches/Red Flag Warnings until
further notice.

On Thursday, the combination of dry fuels, southwest winds
gusting 25 to 35 mph and relative humidity values as low as 10
percent will create critical fire weather conditions. Therefore,
a Red Flag Warning is in effect for Cheyenne and Kit Carson
counties in Colorado as well as Sherman, Wallace, Greeley
counties in Kansas from 17z-03z.

A strong cold front will move through the warning area Thursday
evening, abruptly shifting winds to the north to northwest with gusts
generally up to 40 mph, possibly a bit higher. This will create
unpredictable fire behavior for any fires ongoing. First responders
stay up to date on the position and timing of the cold frontal
passage should any fires occur.

Despite favorable wind and relative humidity forecasts, we`ll be
leaving Yuma county and Cheyenne county Kansas out of the Red
Flag Warning. These area have been hit hard by high rainfall
amounts in Yuma county a few feet of accumulating hail in spots.
NASA Sport 0-10km soil moisture remains rather high and would
likely not support explosive fire growth at this time.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Red Flag Warning from 11 AM this morning to 9 PM MDT this
     evening for KSZ013-027-041.
CO...Red Flag Warning from 11 AM this morning to 9 PM MDT this
     evening for COZ253-254.
NE...None.

&&

$$

UPDATE...99
SHORT TERM...Trigg
LONG TERM...CC
AVIATION...99
FIRE WEATHER...