-- Discussion containing changed information from previous version are highlighted. --
170
FXUS65 KPUB 280512
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
1112 PM MDT Mon May 27 2024

.KEY MESSAGES...

- Isolated storms lingering well into the late night hours
  across the far eastern plains.

- Greater chance for strong to potentially severe thunderstorms
  across the southeastern plains for Tuesday.

- Thunderstorm chances ramping up across the southeast mountains/plains
  through the work week with strong to severe storms possible.

- Drying and warming trend possible late weekend into early next week.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 203 PM MDT Mon May 27 2024

Currently...Plenty of sun across the region today with just some
fair wx CU over the higher terrain and far southeast corner of the
state, with temps warming into the 60s to around 70F for the high
valleys as of 2 PM, and 70s to around 80F for the plains. The area
is on track for another 5 degrees of heating or so for the
remainder of this afternoon.

Tonight...Upper ridge currently over the Great Basin and Four
Corners regions will strengthen and gradually edge to the east
tonight, with isolated convection over the higher terrain pushing
east across the I-25 Corridor and eastern plains. At the surface,
llvl moisture will start to increase from the east to the west as
evident by increasing dewpoints pushing in from KS. As the isolated
convection continues east this evening, storms will move into the
increasing fuel load at the surface and will likely linger into the
late night hours closer to the eastern border. Main threats will be
gusty winds around 45-50 mph, small hail up to 1/2 inch in diameter
and brief periods of moderate to heavy rain. Higher dewpoints
advecting in means a bit more mild for overnight lows, with minimums
in the upper 30s to lower 40s for the high valleys, and mid 40s to
lower 50s for the plains.

Tomorrow...South to southeast surface winds through the morning will
transition to a more easterly direction between 18z-21z, leading to
increased moisture advection and NAM CAPE jumping up into the 2000-
2500 j/kg range through the afternoon. 0-6 km bulk shear increases
to around 45 kts by mid-afternoon as well, so more widespread
convection is anticipated tomorrow with scattered showers and
thunderstorms for much of the area, and convection likely over the
Pikes Peak region as well as the far eastern plains. In addition,
SPC has included all of the area within the general thunder box, and
the southeast corner of the state in a marginal box for severe
storms. Plan on high temps warming into the mid to upper 70s for the
high valleys, and upper 70s to mid 80s for the plains.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 203 PM MDT Mon May 27 2024

Storms will move eastward across the far eastern plains Tuesday
evening with strong to severe storms possible, especially south of
highway 50 and east of a La Junta to Kim line. To the west of this
line, low levels dry out behind the initial wave of convection so
any lingering thunderstorms will be higher based and less intense.
Thunderstorms exits eastern CO by 06z. However outflows will likely
spread higher dew points westward into the mountains by Wednesday
morning. This low level moisture advection will set the stage
for better thunderstorm chances on Wednesday.

Upper ridge axis shifts eastward on Wed with increasing southwest
flow aloft over CO as the next upper trough across the Pacific NW
moves into the northern Rockies by late day.  Lee troughing will aid
in mixing the dry line eastward though this may be a gradual process
without a well defined shortwave to help spread southwesterly winds
off the mountains into the adjacent I-25 corridor until late
afternoon/early evening.  Convection seems to initiate a little
slower given the lack of forcing with the upper trough axis still
well to the west.  However with afternoon heating, thunderstorms
should fire along the southeast mountain, and National Model Blend
probabilities of CAPE greater than 1000 J/kg will be running in the
40-75th percentile range from the I-25 corridor eastward. Deep
layer shear will be 30-40 kt range, thus one or two severe
storms will be possible for the southeast plains with large hail
and damaging winds the primary risks. NBM Probabilities of
1500+ J/kg are greatest across Kiowa, Bent, Prowers and Baca
counties but depending on quality of dew point return (Nam12 is
still on the higher side of the spectrum with this), and
persistence of southeasterly surface flow, higher dew points
could be maintained into El Paso county which would lead to
higher CAPE than model blends portray. Storm initiation may be a
little more difficult for southern portions of the southeast
plains with model soundings showing a cap, but as the low level
jet increases in the evening, one or two thunderstorm clusters
are likely across the plains which could expand the risk for
hail and wind into the eastern counties during the evening
hours, especially north of highway 50. Latest runs push
convection eastward into KS by 06-09z.

Thursday could be another active day for thunderstorms across the
plains with an earlier start to convection as the southern extension
of the upper trough moves across CO during the late morning/early
afternoon.  Thunderstorms will develop over the mountains around
noon and spread eastward.  Depending on how quickly dew points mix
out, mean CAPE values of 1000 J/kg and deep layer shears of 30-40
kts could support one or two strong to severe thunderstorms. Details
this far out get murkier as once again, NAM12 hangs on to some
rather high CAPE values 2000-3000 J/kg across portions of the SE
plains to the north of a surface low.  This is on the 95+ percentile
of solutions according to NBM...so confidence in this is not
high. Thunderstorms push eastward into the plains overnight.

Westerly flow should establish the dry line farther east on
Friday which should shift any strong to severe thunderstorm
risk east of the I-25 corridor.

Overall still looks like a drying and warming trend expected into
early next week with west to southwesterly flow aloft.  12z GFS has
come in anomalously strong with another upper trough dropping in
from the northwest on Monday. EC is much less amplified but does
show NW flow and a slight cool down for Tuesday. Have leaned
towards the warmer and drier consensus of the model blends for
now. -KT

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
-- Changed Discussion --
Issued at 1108 PM MDT Mon May 27 2024

VFR conditions through much of the next 24 hours at all three
terminals. A few showers/thunderstorms may be possible across
the San Luis Valley near KALS Tuesday afternoon, which could
produce gusty winds if they pass near the terminal. Better
potential for showers/thunderstorms at KCOS from mid afternoon
into the evening. Gusty winds could accompany any storms that
move across KCOS. CIGS look to lower at KCOS behind a frontal
boundary by late evening. KPUB looks to remain dry, with CIGS
lowering late Tuesday evening.  Mozley
-- End Changed Discussion --

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SHORT TERM...MOORE
LONG TERM...KT
AVIATION...MOZLEY