FXUS65 KPUB 242152

Area Forecast Discussion
National Weather Service Pueblo CO
352 PM MDT Sun Sep 24 2017

.SHORT TERM...(This evening through Monday)
Issued at 352 PM MDT Sun Sep 24 2017

...Scattered Showers and Below Average Temperatures...

Upper low pressure spinning over northeast Utah and southwest
Wyoming will bring scattered showers and below average temperatures
to the area over the next 24 hours.  Upslope across the plains will
keep it on the cloudy side with bouts of showers and a few evening
thunderstorms.  The upslope flow across the plains is weakening at
this time.  This will continue into the evening before increasing
again late tonight through Monday as an upper level disturbance
swings this way and reinforces the upslope.  Mostly cloudy skies,
scattered precipitation, and below average temperatures will
continue over the east in response.

Over the mountains and high valleys there is no low level upslope
flow to bring in the low clouds.  Consequently, there has been a
great deal more sunshine in those areas.  There may be a few evening
showers or thunderstorms around but after the sun sets, there should
be quite a bit of clearing leading to freezing temperatures in many
areas by Monday morning.  Leadville, that was already down to 31
degrees this morning, will probably drop into the lower 20s. Alamosa
and many of the agricultural areas of the San Luis Valley will
probably see a widespread freeze tonight with temperatures generally
ranging from the mid 20s to lower 30s.  A Freeze Warning is in
effect for the valley from 3 AM to 9 AM Monday.  Tender plants
should be protected or brought indoors.

There could also be some snow showers in the mountains overnight,
generally above 8,000 feet.  But nothing too widespread or heavy is
anticipated at this time.  Mainly just a local dusting less than an
inch here and there.

.LONG TERM...(Monday night through Sunday)
Issued at 352 PM MDT Sun Sep 24 2017

Monday night-Tuesday night...Models continue to indicate splitting
energy across the region with the main upper trough lifting out
across the Northern Rockies Monday night, as secondary energy digs
down the backside of the system and develops a closed low across the
southern Great Basin through the day Tuesday. With that said, should
see scattered showers across the area diminishing though Monday
evening with some clearing into Tuesday morning, especially over the
higher terrain, as drier air within the westerly flow moves across
the area. Tuesday looks relatively dry across the area, though can`t
rule out some isolated afternoon showers, mainly over and near the
higher terrain. With cool air in place, low temperatures across the
higher terrain and high mountain valleys to cool to at and below
freezing, but will not go with a freeze watch for the San Luis
Valley, as will see how low tonight`s temps will go in the SLV.
There could be some morning stratus across the eastern Plains Monday
morning, and with the cool air and weak low level upslope in place,
highs Tuesday will be below seasonal levels, with mainly 50s and 60s
across the lower terrain and 30s to low 50s across the higher

Wednesday-Saturday...Lower confidence forecast through the rest of
the week and into the early weekend, as models are struggling on
location and timing of secondary energy across the Great Basin
lifting back out across the Rockies. Models do indicate the system
digging it into the Desert SW into Wednesday night, with the GFS
then further east with the system as if lifts out across south
Central Colorado through the day Friday where as the ECMWF is
further north and west with the system. The EC solution would keep
most of the precipitation associated with the system over and near
the higher terrain, with best coverage across the ContDVD, where as
the GFS solution would bring better chances of precipitation to the
eastern Plains. With that said, have stayed closer to blended model
solution, which slowly increases precipitation chances across the
higher terrain through Wednesday night and then spreads chances east
through Thursday night before decreasing areawide into early next
weekend. Temperatures to slowly warm through the period, though
remaining below seasonal levels through the end of the work week.


.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 352 PM MDT Sun Sep 24 2017

Upper low pressure area spinning over northeast Utah and southwest
Wyoming at this time. Upper low will stay in approximately the same
location through Monday. Areas of MVFR to LIFR CIGS and VSBYS will
continue over the eastern slopes and plains over the next 24 hours
with scattered showers and storms. Meanwhile, generally VFR over the
western slopes and high valleys, with isolated showers and storms
producing local MVFR to LIFR conditions. KCOS has gone briefly VFR
for a few hours this afternoon. KPUB got close with breaks in the
overcast noted nearby but it didn`t quite happen. Sub-VFR conditions
will likely resume overnight as upslope flow increases in response
to an approaching upper disturbance being pushed eastward from the
main upper disturbance.


Freeze Warning from 3 AM to 9 AM MDT Monday for COZ069>071.




NWS PUB Office Area Forecast Discussion