335
FXUS65 KPUB 121038
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
438 AM MDT Sun May 12 2024

.KEY MESSAGES...

 - One more round of rain, higher elevation snow, and
   thunderstorms today before storm departs tonight.

 - Showers are expected each afternoon Monday and Tuesday, with
   most showers remaining around and along the mountains.

 - Unsettled weather returns for part of the midweek period,
   with high (60-79%) confidence in widespread precipitation
   chances, but low (20-39%) confidence in precipitation
   amounts.

 - Quieter weather is anticipated for the end of the week and
   start of next weekend.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 435 AM MDT Sun May 12 2024

Active morning so far with 17 inches of snow falling in an 9 hour
period at Leadville in Lake county last evening and overnight.
Webcams at Fremont Pass and Leadville shows some heavy snow
accumulations and this area is under the TROWAL/wrap around band of
precipitation along the northern side of the upper low centered
across southwest CO as of 09z. Convective enhancement has helped
precipitation and snow accumulations over-perform as is typical of wet
spring storms. Question will be how much of this will continue
across our area as the upper low pulls eastward and this
precipitation band spreads south and eastward with time. High res
models have been increasing QPF across Fremont and Teller counties
as well as the upper Arkansas river valley. Although loss of heating
would suggest less widespread convective enhancement this morning,
persistent lightning with convective elements continues to percolate
along the front range which is funneling moisture into the central
mountains.  Will follow the trends of the high res models and expand
advisories eastward into portions of Teller and Fremont counties
this morning. Temperatures in Teller county have already dropped to
around freezing and model soundings have been showing the potential
for snow levels to drop to around 8500 feet this morning. Warmth of
ground may mitigate impacts below 9000 feet, but can`t rule out some
heavy wet slushy accumulations during the heavier precipitation
rates this morning.  Have limited advisories to the morning hours
for now as snow levels are advertised to rise again this afternoon.
Central mountains will see advisories and warnings continue through
15z and it is possible that extensions of the advisories may be
needed for southern areas through 18z depending on how consolidated
this wrap around band maintains.

Elsewhere will see rain showers across the lower elevations below
9000 feet with lighter snow accumulations across the higher areas of
our southern mountains due to the storm track. Across the plains
today, showers and thunderstorms will redevelop this afternoon with
the potential for a few strong to marginally severe storms across
the far eastern plains towards 21z.  HREF mean CAPE stays below 1000
j/kg with better shear to the east.  But for a any early afternoon
development there is the potential for higher CAPE before the
surface dew point mixes out behind the boundary. Hail up to quarter
size and wind gusts up to 60 mph will be the primary risks.
Depending on the position of the boundary and timing of storm
development, can`t rule out a landspout if it can tap some resident
vorticity along a more stationary segment of the boundary. Baca and
Prowers counties may have the best chance for this, albeit this
probability still looks low and mesoscale trends will need to be
monitored closely.

Like yesterday, leaned towards the cooler side of guidance for high
temperatures today where precipitation is likely to affect heating.
Went closer to model blends farther east.  Clearing takes place
overnight so went on the cooler side of guidance for the valleys.
May need to monitor these areas for potential ground fog
development towards morning. -KT

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 435 AM MDT Sun May 12 2024

Monday - Tuesday: The start of the new week will bring some active
weather to south central and southeastern Colorado, with daily
chances of showers. A messy shortwave ridge will drift over the
region, and while no major synoptic forcing is expected with this
feature, minor orographic forcing will continue. This forcing, in
combination with modest moisture still in place, will allow for
showers to blossom each day, particularly along and immediately
around the mountains. And while most precipitation is anticipated to
remain around and along the mountains both days, a weak front from a
wave to the north Tuesday afternoon may help to blossom additional
showers across the eastern plains as it sags southward. Snow showers
are expected for the peaks of the mountains, with rain showers and
thunderstorms expected elsewhere. With all of that said, as diurnal
instability wanes each day, any showers across the region are
expected to weaken and dissipate heading into the overnight hours.
As for temperatures, a warming trend is anticipated. Much of the
area will warm to near to above seasonal temperatures for mid May.

Wednesday - Thursday: For around the midweek period, more active
weather is anticipated for the region. An unsettled pattern will
develop over the area, as two lows/waves try to interact with each
other. Ensemble model guidance is in good agreement about these
features trying to phase with each other, but there is still some
disagreement about timing of the phase and how much they phase
together. Overall, there is high confidence (60-79%) this pattern
will bring more widespread precipitation chances to south central
and southeastern Colorado as the waves pass over the region.
However, given some uncertainty in how these lows/waves will
eventually interact, confidence is low (20-39%) in how much
precipitation falls. With that said though, the gap between the
lowest ensemble model and the highest ensemble model has closed
some, so this could be trend toward a more particular solution, and
hopefully details on that will become more clear over the next few
days. Looking at temperatures, much of the area will cool down to
below seasonal values given the unsettled pattern over the region.

Friday - Saturday: For the end of the week and into the weekend, a
downtick in active weather is expected for south central and
southeastern Colorado. Flow will develop into a more ridging
pattern, and no major sources of forcing are expected to influence
the region. Ensemble model guidance are in relatively good agreement
on this pattern change, though are a bit more flat with the ridging.
With no major forcing, dry conditions are expected for the region,
though an an isolated shower can`t be ruled out along the mountains
given weak orographic forcing. Then, as for temperatures, a rebound
to warmer values is expected, as much of the area warms to above
seasonal values for mid May.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 435 AM MDT Sun May 12 2024

KCOS...Patchy LIFR to VLIFR fog will erode quickly by the 12z TAF
issuance with -SHRA spreading into the terminal this morning as
north winds increase behind a cold front.  Gusts up to 25 kts will
be possible through the day with predominantly MVFR cigs/vis with -
SHRA.  Improving conditions can be expected by late afternoon with a
return to VFR conditions after 00z.

KPUB...MVFR to VFR conditions expected at KPUB with another round of
-SHRA late this morning into the afternoon.  While VCTS is possible,
think probabilities will be higher to the east of the site and will
maintain VCSH for now.  Winds will increase out of the north and
gust up to 25 kts this afternoon.  Activity should pull eastward
with improving conditions after 00z.

KALS...MVFR cigs possible this morning with the potential for some
IFR fog/stratus through 14z.  -SHRA will be possible at the terminal
by mid morning through early afternoon with MVFR cigs.  Improving
conditions expected late afternoon into the evening with a return of
VFR conditions. -KT

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 9 AM MDT this morning for
COZ058>060.
Winter Weather Advisory until 9 AM MDT this morning for COZ061.
Winter Weather Advisory until noon MDT today for COZ063-076-
081-082.

&&

$$

SHORT TERM...KT
LONG TERM...SIMCOE
AVIATION...KT