co discuss
Office: BOU
FXUS65 KBOU 061148
AFDBOU
Area Forecast Discussion
National Weather Service Denver/Boulder CO
448 AM MST Fri Mar 6 2026
.KEY MESSAGES...
- Snow spreads from the high country over the lower elevations
this morning. Difficult travel expected for mountains,
foothills and Palmer Divide with moderate to heavy snow at
times.
- Snow trends are increasing for metro Denver. Morning commuters
should prepare for slick conditions. Possible refreeze this
evening.
- Snow tapers off and ends late this afternoon/evening north to
south.
- Milder and drier weather expected Saturday into early next
week.
&&
.DISCUSSION /Through Thursday/...
Issued at 1251 AM MST Fri Mar 6 2026
An upper level trough will move across the area Fri into Fri night.
An upper level low will be over swrn CO by 12Z Fri and then move
ENE into nern CO by Fri aftn and then into west central NE by Fri
evening. QG fields still have favorable QG ascent affecting the
area thru Fri aftn and then weakening by Fri evening. Meanwhile,
cross-sections continue to show N or NNE low level flow thru the
aftn as a secondary front moves across the plains. Data from OOZ
models have increased QPF across most of the Plains, Palmer
Divide and srn Foothills as well as the Denver Metro area. As a
result, there appears to be an increasing chance of heavier snow
affecting portions of the Denver metro extending ene across
portions of the Plains. Latest data also has snow developing
by 10Z along the I-25 Corridor from Denver north to Fort Collins
which could impact the morning commute as heavier snow moves in
after 12z.
Based on current trends, have upgraded the southern Foothills to
a warning and have decided to issue an advisory for the Denver
metro due to potential impacts in the morning when heavier snow
may occur. Further east over the plains, heavier likely won't
develop until midday/early aftn, so will hold off on an advisory
for now as not sure exactly where a heavier snow band may develop
to the north and northwest of the upper level low's path.
By Friday night, snowfall should gradually diminish by early evening
along the front range but will continue over the northeast plains
thru mid evening. Will also see snow continue in the I-70 mtn
corridor and srn Foothills thru mid evening before ending by
midnight.
Moving into Sat, will see drier air spread across the area in NW
flow aloft. Biggest concern for Sat will be high temps, depending
on how much snow cover there is from the I-25 Corridor across the
plains. Where snow cover exits highs may stay in the lower to mid
40's while areas with less snow cover may reach the upper 40's to
lower 50s. Since at this point I don't know what the snow cover may
look like, have kept the blended solution in for now which has
readings in the upper 40's to lower 50s across the plains.
On Sun, mainly dry WNW flow aloft will be across the area as a sfc
lee trough begins to develop east of the mtns. As a result, this
should lead to warmer temps as downslope low level flow develops,
with readings rising into the lower to mid 60's over the plains.
For Mon and Tue, westerly flow aloft will be over the area with
downslope low level flow continuing. This will allow for highs in
the upper 60s to lower 70's over the plains. In addition, will see
periods of gusty winds over the higher terrain as well.
By Wed, the flow aloft may become more WNW, with current data
only showing some higher level moisture embedded in the flow.
There will be a cool front moving across the plains Tue night into
Wed morning so aftn highs may drop back into the mid 50's to
lower 60s across nern CO,
&&
.AVIATION /12Z TAFS through 12Z Saturday/...
Issued at 448 AM MST Fri Mar 6 2026
Snow will spread across the Denver metro TAF sites including KDEN
through 14Z. We having growing confidence that areas of moderate
snow will be developing shortly thereafter (15Z-17Z) as the low
levels saturate and moisture profiles deepen under increasing
synoptic and mesoscale lift. That snow is expected to continue of
near moderate intensity with visibility down to ~1/2SM at times and
Cigs/vertical visibility near 500 feet through 21Z, with a chance
it lasts a little longer than that near KAPA due to better
orographics in northerly flow. Lighter snow (visibility 1-3SM and
cigs 006-012) is then likely to linger til about 03-04Z before
cigs lift and skies clear rather quickly behind storm system.
Expect VFR conditions by 06Z-08Z, and mostly clear skies for
remainder of TAF period.
Depending on snow rates, the majority of the snow should melt on
runways, but during periods of heavy snow some slush/shallow snow
is certainly possible this morning. Increased solar insolation
middle of the day should keep runways mostly wet this afternoon,
but a 50-70% chance of refreeze mid evening with continuation of
light snow and colder temperatures dropping into the upper 20s.
Generally light north winds are prevailing to start this TAF, with
an expected increase with another surge of a cold front 16Z-17Z.
Then look for gusts averaging about 25 kts from almost due north
through at least 01Z, gradually diminishing as snow ends 03Z-04Z.
Then normal light drainage winds from the southwest are
anticipated to develop with those clearing skies after 06Z. Those
winds will also keep any fog threat well north of KDEN.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until midnight MST tonight for COZ030-
032-035-037.
Winter Weather Advisory until 8 PM MST this evening for COZ031.
Winter Storm Warning until midnight MST tonight for COZ033-034-
036.
Winter Weather Advisory until 8 PM MST this evening for COZ039-
040-045.
Winter Weather Advisory until midnight MST tonight for COZ041.
&&
$$
DISCUSSION...RPK
AVIATION...20
Office: PUB
FXUS65 KPUB 061202
AFDPUB
Area Forecast Discussion
National Weather Service Pueblo CO
502 AM MST Fri Mar 6 2026
.KEY MESSAGES...
- More widespread snow today with convection wild card giving
some eastern slopes zones the potential for seeing up to 12
inches of snow.
- Lingering isolated snow showers into Saturday then drying out
and warming up again with a dip in temperatures for Wednesday
behind a dry cold front.
- Spotty critical fire weather conditions returning for portions
of the area next week as westerly flow aloft increases again.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 1228 AM MST Fri Mar 6 2026
Upper low is taking shape across UT tonight with showers developing
across western CO along the tightening baroclinic zone/mid level
front. System is progged to close off just north of the Four Corners
region before shifting eastward across CO then lifting to the
northeast into western NE by this evening. More energy drops down
the back of the mean trough out west which cuts off and
retrogrades across the Desert Southwest into southern CA by
Saturday morning. This keeps CO within the upper trough axis
through Saturday which will play a role in how long precipitation
lingers tonight into Sat(more on this a bit later).
Snow will spread eastward into the Continental Divide overnight,
spilling into the southeast mountains, Pikes Peak region, and
adjacent valleys towards 12z. Rain and snow showers will expand eastward
into the I-25 corridor counties Friday morning pushing east into
the adjacent plains through the afternoon before pulling off the
northeast during the evening. An orphaned a circulation
center/vort max within the upper trof axis over southern CO
lingers through tonight suggesting snow may persist past midnight
across the mountains and interior valleys, albeit with lower
snowfall rates.
As the upper low closes off, high res models suggest a period of
east to northeasterly H7 flow funneling into the the Wets,
Northern Sangres and Upper Arkansas river valley. With good run
to run continuity, and the probabilities of greater than 6 inches
of snow increasing in both HREF and NBM to over 70%, have
increased QPF and Snow totals for these areas, necessitating
expansions of the current suite of Winter Weather Advisories.
There will be embedded convection that could push some snowfall
totals to around a foot or more, with NBM and HREF placing some
spotty areas of 40-50% of exceedance along the higher east facing
slopes of the Wets, northern Sangres and southern Sawatch Range
in western Chaffee County. 12 inches is the high end of advisory
criteria or low end of warning criteria for mountain zones, and
it's still conceivable that some localized upgrades to warnings will
be needed for these areas. However, given the storm track and
pattern recognition, it's difficult to have high confidence in
hitting widespread enough warning criteria in these zones without
seeing where the embedded convection sets up. Models/HREF
Ensembles do show a couple hundred J/kg of CAPE across the
mountains, which expands eastward across southern portions of the
plains today. Highest probability of embedded convective elements
still seems focused across the Wet mountains and Pueblo county
today. So this may be the area that gets some higher precipitation/snow
totals, however this focus could shift a bit farther south
depending on the position of the front in the afternoon as it lays
up somewhere to the south of highway 50 in the afternoon.
Otherwise, this does look like a colder system with ptypes
starting out as snow across the mountains/valleys and the Pikes
Peak region with the initial onset of precipitation, and staying
all snow through the entire event. Even in Pueblo, a rain/snow mix
or even a switch over to snow will be possible during the heavier
precipitation rates as snow levels waver down to 4500 feet or
even lower at times. Snowfall will not likely stick around though
due to warm surface temperatures, so don't think southern El Paso
or Pueblo counties will need highlights, though there will be the
usual local variability nearest the mountains. Of further note,
southern and southeast portions of the area will be dry slotted
given the storm track, so the southern San Luis Valley and
southeast zones like Baca county may not pick up much/if any
precipitation through the event. These areas are where the warmer
temperatures will reside today, especially Baca county where
highs may top out near 60 while the majority of the lower
elevations stay in the 40s.
For tonight, high res models linger precipitation across south
central CO well into the overnight hours even as the main forcing
from the northern stream system pulls off to the east. This appears
to be tied to the orphaned circulation/vort center which gets
sheared westward within the trough axis. Bumped up pops accordingly
across the southern mountains/interior valleys into the overnight
hours. We may need to consider some advisory extensions in time,
but will let later shifts assess this need with future model runs.
Snowfall intensities should be on the decline through the overnight
hours as the flow aloft weakens and the synoptic lift decreases.
Stuck close to NBM lows overnight given the persistence of some
cloud cover.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 1228 AM MST Fri Mar 6 2026
Lingering moisture within the upper trough axis will keep some
isolated showers over the mountains on Saturday due to lingering
instability with the upper trough axis. However, most of the area
will dry out and warm up. Winds will be fairly light so no fire
weather highlights are expected. Temperatures rebound nicely
for Sunday with readings back into the 60s to lower 70s across
the plains, 50s for the valleys and 30s and 40s for the
mountains. Drier air pushing in from the north should keep all
areas dry and winds will remain light.
West to northwesterly flow aloft increases next week as the old cut
off low off the coast of the Baja Peninsula eventually pushes
eastward well to the south of CO. Main affect for southern CO
will be increasing winds and warm temperatures as we come under
the influence of the northern stream flow. There will be a
brief cool down behind a cold front for Wednesday as the flow
aloft buckles a bit southward. Spotty critical fire weather
conditions may make return appearances along the I-25 corridor
and southern portions of the plains next week as lee troughing
returns. Temperatures will stay above normal through the
period. -KT
&&
.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 447 AM MST Fri Mar 6 2026
MVFR and IFR conditions expected to develop at COS, PUB and ALS
as showers move over and near the higher terrain into the I-25
Corridor through the morning. Increasing coverage of showers
will bring potential for LIFR conditions, especially at COS,
with heavier snow showers through the afternoon. Secondary cold
front looks to bring gusty northerly winds to COS and PUB between
22Z-24Z with precipitation ending thereafter and cigs rising to
MVFR/low VFR. Strong northerly winds slowly diminish through
the late evening hours. Trailing energy will keep showers
in place across the San Luis Valley through the evening, with
breezy southwest winds this afternoon becoming easterly aft
06Z.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until midnight MST tonight for
COZ058>063-068.
Winter Weather Advisory until midnight MST tonight for
COZ072>082-084.
&&
$$
SHORT TERM...KT
LONG TERM...KT
AVIATION...MW
Office: GJT
FXUS65 KGJT 061127
AFDGJT
Area Forecast Discussion
National Weather Service Grand Junction CO
427 AM MST Fri Mar 6 2026
.KEY MESSAGES...
- Showers become widespread tonight, favoring the central
mountains. Snow levels drop below 5000 feet by early tomorrow
morning, allow snow to reach most valley floors.
- All Colorado ranges, and the eastern Uintas, are expected to
see a general 6-12 inches of new snow by Saturday morning,
with potential impacts to the Friday morning and evening
commutes.
- Below normal temperatures are expected tomorrow, followed by
drier and warmer conditions Saturday into early next week with
temperatures gradually warming back to 10 to 15 degrees above
normal.
&&
.SHORT TERM /THROUGH SATURDAY/...
Issued at 1058 PM MST Thu Mar 5 2026
As expected, cold air has begun to infiltrate the region. This has
introduced light rain and snow across the region over the past hour.
Conditions will continue to deteriorate as the cold front settles in
and snow showers continue across the mountains. The latest model run
has increased moisture a bit, especially over southwest Colorado,
where I added COZ017 to the Winter Weather Advisories for an uptick
in snow on the Uncompahgre Plateau. Friday morning commuters will
see snow packed roads across the mountains, as snow continues
through the overnight hours. The frontal boundary will drag through
the region slowly Friday morning, with measurable snow continuing
across the mountains through the day. Instability behind the front
is expected to produce some heavier showers, along with stronger
winds. This could make for an interesting evening commute Friday
across the mountains. Widespread snow totals of 6-12 inches are
still expected across the mountains, with some locally higher
amounts.
Late Friday night, dry air begins to over-run the region, as height
rises from the encroaching ridge of high pressure take over. This
will taper precipitation rapidly from northwest to southeast, taking
our northern mountains off the advisory list. Snow will continue for
the Central and Southern Mountains into early Saturday, with
advisory conditions pretty much wrapping up after midnight. Snow
packed roads will hang around into Saturday morning. Clouds will
clear off Saturday morning across the region as high pressure
returns. This will bump afternoon highs back up a notch, to around
normal across the region. Models are keeping a few pop up showers on
the San Juans Saturday afternoon, especially where sunshine can poke
through the clouds and destabilize a bit. Accumulations should be
minimal. Clear and cold conditions return Saturday night across the
region.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Issued at 1058 PM MST Thu Mar 5 2026
A retrograding cut off low will split off the main upper trough over
the northern Baja by Saturday night into Sunday with northwest flow
returning over the western slope as the polar jet remains north of
the region. Models are not in great agreement with the exact track
of this cut off low but generally have it tracking eastward across
southern Arizona and New Mexico Sunday into Monday before lifting
slightly northeast into Texas by Tuesday into Wednesday. The GFS is
further south while the ECMWF is maintaining its track a bit further
north. Regardless, the sensible weather for eastern Utah and western
Colorado remains the same with dry conditions Sunday through much of
the coming week and a warming trend back towards above normal
temperatures. The blended forecast is indicating the possibility of
mountain showers on Tuesday but this is dependent on the exact track
of this cut off low to our south and if it phases with a shortwave
tracking across Wyoming to our north. Both synoptic features
narrowly miss us but we could see steep enough lapse rates and
enough lift to produce a few showers over the high terrain.
Confidence on any precipitation next week is low however given these
subtle differences with dry conditions and warming temperatures
being the primary driver of the sensible weather as highs reach 10
to 15 degrees above normal through the coming week.
&&
.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 418 AM MST Fri Mar 6 2026
Snow is expected to continue over KASE, KEGE, KRIL, KMTJ, KTEX,
KGUC, and KHDN through much of Friday. There is a lower
potential for precipitation at KGJT and KDRO. Where storms pass
through, cigs are likely to fall below ILS breakpoints (as many
terminals are already under these conditions). Higher elevation
terminals could see vis drop to LIFR, and MVFR to IFR conditions
will be possible at lower elevation terminals. Some gusty winds
of 15-25 kts may also develop at KRIL, KGJT, KTEX, KDRO, KHDN,
and KVEL this afternoon.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...Winter Weather Advisory until 6 PM MST this evening for COZ004-
009-013.
Winter Weather Advisory until midnight MST tonight for COZ010-
012-017>019.
UT...Winter Weather Advisory until 6 PM MST this evening for UTZ023.
&&
$$
SHORT TERM...BGB
LONG TERM...DB
AVIATION...TGJT
