Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/28/16
Area Forecast Discussion
National Weather Service Pueblo CO
319 PM MDT FRI MAY 27 2016
.SHORT TERM...(This evening through Saturday)
Issued at 319 PM MDT Fri May 27 2016
Rest of today...Upper low over eastern CO and western KS will
continue to pull off to the northeast. Area of showers and
thunderstorms has been developing in area of wrap around...with
most intense cells in southern CO developing across Kiowa county.
High res models continue to show best activity across far northeast
sections of that area through late afternoon and early evening before
activity pulls off to the northeast and diminishes overnight.
Main threat will be local wind gusts to around 50 mph along with
some small hail.
Remainder of the area could see some scattered showers and isolated
embedded thunderstorms this afternoon through early
evening...particularly over the mountains but these too should
diminish with loss of heating. Elsewhere, gusty north to northwest
winds will continue across the plains into the early evening, before
winds weaken overnight.
For tomorrow...weather looks much more quiet with shortwave ridging
aloft. There will still be sufficient moisture for thunderstorms,
particularly in and near the mountains. However, limited
instability, with CAPE values generally around 500 J/KG, storms
will remain on the weaker side, with gusty winds up to 50 mph and
lightning being the primary storm threats. Storms will initiate
over the higher terrain before slowly moving across the plains
during the afternoon and evening hours. High temperatures across
the plains will rebound back into the upper 70s with mid to upper-
60s expected across the high valleys. Overnight, temperatures will
be on the cooler side with lows approaching the freezing mark in
the San Luis Valley.
.LONG TERM...(Saturday night through Friday)
Issued at 319 PM MDT Fri May 27 2016
Saturday night-Sunday night...Drier westerly flow aloft across the
area Saturday gives way to increasing southwest flow Saturday night
and Sunday ahead of an embedded disturbance translating across the
southern Rockies through Sunday night. Some differences in models on
location of this embedded disturbance with the latest NAM and GFS
seemingly overdone with WAA precipitation across the far southeast
plains Saturday night. At any rate, isolated to scattered showers
and thunderstorms across the area Saturday afternoon to diminish
through the evening, though did keep slight pops across the far se
plains through the overnight hours. Increasing UVV and moisture
ahead of the southern Rockies wave looks to bring a better chance of
showers and storms across the area Sunday afternoon and evening,
with stronger storms still possible across the far SE Plains, as lee
troughing across the southeast plains helps dry line across western
Kansas to retrograde. Temperatures look to warm back to around
seasonal averages by Sunday.
Monday-Wednesday...A relatively cool and unsettled weather pattern
remains in the offing through the middle of next week, as more
energy translates across the southern Rockies, with another upper
wave slowly digging across the northern Rockies Monday and into the
central High Plains through Wednesday. There are some differences in
model location and timing of features, though a cold front looks to
move across the plains late Monday night and through the day
Tuesday, supporting the potential for possible severe weather and
locally heavy rainfall Tuesday and Wednesday. Could also see some
more higher elevation snowfall through this period, depending on the
track of the upper level features.
Thursday-Friday...A slow warming and drying trend for late next week
as upper level ridging across the Desert Southwest and Great Basin
is progged to build into the Rockies.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 319 PM MDT Fri May 27 2016
VFR conditions are expected at the TAF sites throughout the period.
Winds will continue to remain gusty at KPUB and KCOS through 02Z,
before winds decrease overnight. A few showers will continue to
linger around KPUB and KCOS through about 03Z before activity
diminishes overnight. Showers and thunderstorms will form over the
higher terrain starting around 17-18Z tomorrow afternoon. KALS and
KCOS may see VCTS starting around 20Z.
&&
.PUB Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...KT
LONG TERM...MW
AVIATION...KT
[top]
Area Forecast Discussion
National Weather Service Denver/Boulder CO
1248 PM MDT FRI MAY 27 2016
.UPDATE...
Issued at 1204 pM MDT Fri May 27 2016
The suns heating over the far northeast corner of the state has
allowed for some additional destabilization. May see a stronger
storm east of a line from Sterling to Limon. The main threat from
these storms would be hail up to an inch and possible gusty
outflow winds to 40 mph.
UPDATE Issued at 1041 AM MDT Fri May 27 2016
The band of rain across the eastern plains is decreasing in area
as well as intensity late this morning. The band is slowly moving
west but is expected to continue to weaken. Rainfall rates will
likely be below a tenth of an inch an hour below the band, and
will continue to lessen. As the day`s heating continues, am still
expecting a few thunderstorms to be able to develop this afternoon
across the forecast area. However with weak CAPE but a cooler
airmass, could still see small hail falling out from them.
Downward QG vertical velocities along with drying downsloping
pattern will diminish showers and thunderstorms this evening, with
only a slight chance of them remaining in NW flow over the
mountains. There is still thunderstorms in the forecast this
evening, however conditions don`t look very favorable, may strip
these out later.
&&
.SHORT TERM...(Today and tonight)
Issued at 350 AM MDT Fri May 27 2016
The upper level low will track across southeast Colorado and into
western Kansas today. A deformation band has developed on the back
side of the low. This area of rain should shift east with the low
this morning. Lowered pops for the northern half of the Front
Range. Will keep the higher pops south and across the eastern
plains due to the area of rain. Rainfall will be light to moderate
with additional amounts mostly less than a half inch. Most of the
precipitation has remained east of the mountains and is expected
to stay east, so will cancel the Winter Weather Advisory.
Airmass becomes slightly unstable this afternoon, mainly over the
higher terrain and far northeast corner of the state. Will have
scattered showers and thunderstorms in the forecast for this with
higher pops over the eastern plains where the deformation zone is
expected to be.
Rain showers and thunderstorms are expected to decrease late this
afternoon and evening as the airmass stabilizes and the low moves
east of the state. Will have low pops in the for the evening and
then end them most locations after midnight. There may be a few
stray showers over the mountains and far northeast Colorado after
midnight and will keep slight pops in the forecast.
.LONG TERM...(Saturday through Thursday)
Issued at 350 AM MDT Fri May 27 2016
The Memorial Day weekend should start out dry Saturday morning
with a weak mid-level shortwave ridge over the area and a light
west-northwesterly flow spreading drier and warmer air over the
fcst area. by afternoon some of the models show this ridge nosing
up into the Dakotas and a weak shortwave trough on its heels
passing over the CWA during the late afternoon/early evening
hours. Strong solar heating resulting in steep lapse rates and the
lingering presence of low-level moisture should manage to produce
isolated to scattered showers/t-storms over the Front Range mtns
and higher foothills by early afternoon. Destabilization aloft and
additional heating of the boundary layer may be sufficient to
spark a few late afternoon/evening t-storms on the plains and
Palmer Divide. Potential instability and shear do not appear
adequate to produce strong/deep convective updrafts leading to
severe t-storms. Furthermore qpf guidance indicates the bulk of
the precip that day will fall over higher elevations...and most of
that less than a quarter inch. As for Temperatures on
Saturday...model guidance indicates a 10-12deg f warmup for most
areas. That seems reasonable with the warming aloft and with a few
more hours sunshine.
Sunday may begin about the same with morning sunshine and mild
temperatures. however by mid to late morning a tight lee slope
pressure gradient creates gusty south-southeasterly sfc winds on
the plains according to the NAM...GFS and Canadian models which
then drives increasing amounts of low-level moisture up into
east-central and northeast Colorado. Could see isolated to widely
scattered t-storms forming on the plains by mid-afternoon...but
the stronger convection will probably stay east of the CWA as it
now appears. Meanwhile mountain areas should again see another
round of afternoon and early evening showers/t-storms but probably
with the coverage expected on Saturday since there does not appear
to be any forcing mechanism aloft. Sunday temperatures should
continue to rise by another 3-5 deg f for most locales with mid-to-
upper 70s on the plains.
For Memorial day...models are offering mixed signals. The NAM
shows another shortwave trough swinging over the area during the
day and interacting with a moisture rich sely low-level flow
together with bndry layer cyclongensis across the northeast
corner of the state. This would potentially result in a stormy
afternoon and evening for this area. Whereas...the GFS...ECMWF
and Canadian models indicate a drier day for the CWA with a warm
and dry swly flow aloft. I like a blend of the models here since
I`m not sure the boundary layer will dry out as much as the models
indicate as they all generally indicate sely sfc winds on the
plains. Temperatures on Monday about the same or perhaps a deg or
two lower than the day before.
For the period Tuesday-Thursday...models continue to indicate
troughing over the Rocky Mtn Region and as a result a slight dip
in temperatures and a slightly better chance of afternoon and
evening showers/t-storms. The best chance for this activity
appears to be on Tuesday and Wednesday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1244 PM MDT Fri May 27 2016
A few weak thunderstorms have formed near KDEN, tracking north to
south. With low freezing levels, even weak thunderstorms will have
the ability to produce small hail. At this time, it looks like TS
should stay east of KBJC and KAPA so will keep it out of their
TAFs. Ceilings are expected to range from 5000 to 6000 feet
through 22z except for near 3000 feet in SHRA/TS, then start
improving through the rest of the afternoon and clear out this
evening. Gusty north to northeasterly winds with gusts to 25
knots possible will decrease after 00z and eventually back toward
drainage. Light winds are expected through 18z Saturday.
&&
.BOU Watches/Warnings/Advisories...
None.
&&
$$
UPDATE...Kriederman
SHORT TERM...Meier
LONG TERM...Baker
AVIATION...Kriederman
[top]
Area Forecast Discussion
National Weather Service Grand Junction CO
312 AM MDT FRI MAY 27 2016
.SHORT TERM...(Today through Saturday)
Issued at 311 AM MDT Fri May 27 2016
A few showers continue this morning due to wraparound flow from
the low that brought the rain and storms yesterday with occasional
snow being reported at the highest elevations. These showers will
weaken as the night progresses but not completely end so you may
see a few raindrops for the morning commute along and south of the
I-70 corridor as well as portions of the San Juans.
While a ridge does build in today, plenty of moisture and daytime
heating will allow another day of showers and storms. Intensity
and coverage will be somewhat less since the area of low pressure, and
forcing it provided, will have shifted well to our east. Like
Thursday, convection should start firing around noon and continue
through sunset with some spotty showers continuing through
midnight.
Flow becomes more zonal Saturday as a weak wave moves over the
region allowing another afternoon and evening of unsettled
weather. Models paint precip over the highest terrain which looks
good as steering winds are quite weak during this timeframe.
Outside of those areas, partly cloudy skies are expected with
temperatures finally reaching more normal values.
.LONG TERM...(Saturday night through Thursday)
Issued at 334 PM MDT Thu May 26 2016
The long wave trough will reload along the west coast during the
weekend as the next low pressure disturbance develops over
southern California. The flow over our area will quickly become
southwest again by Sat. This relatively unstable flow will carry
enough moisture to keep afternoon convection in the
forecast, mainly along the mountains.
Models show this low weakening as it gradually tracks east early
in the work week. Also a stronger low center over the Pacific
northwest will shift east. As both of these features head east,
high pressure will develop along the west coast. So continued
mainly mountain convection can be expected each afternoon through
Tue. Then the west coast ridge will strengthen and move into the
Great Basin for warmer and drier conditions midweek and beyond.
Temperatures are expected to be a tad below normal during the
weekend, then right around normal through the first half of the
work week. Temps will then climb to just a tad above normal by
the end of the period.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 311 AM MDT Fri May 27 2016
Mid level clouds continue to hang around this morning with cigs
varying from about 3.5K feet at ASE up to 10K feet at DRO. Cigs
should lift through the morning hours as the low pressure to our
east continues moving in that direction. A few showers will likely
persist though so those TAF sites near and under the showers may see
the lower cigs persist. KASE...KEGE...KTEX...KRIL and KGJT look to
have the best chance for this to occur. vcsh looks safe for those
sites for the next few hours until some clearing occurs. After
18z...more convection is expected though coverage will be less.
Not sold on any one TAF site actually seeing a -tsra on station so
will leave out for now. By 02z...most convection will end though
some stray showers will persist. Even mentioning the convection
and showery precip, still expect mostly vfr conditions today.
&&
.GJT Watches/Warnings/Advisories...
CO...Winter Weather Advisory until 6 AM MDT early this morning for
COZ010-012.
UT...None.
&&
$$
SHORT TERM...TGR
LONG TERM...EH
AVIATION...TGR
Area Forecast Discussion
National Weather Service Pueblo CO
325 PM MDT THU MAY 26 2016
.SHORT TERM...(This evening through Friday)
Issued at 325 PM MDT Thu May 26 2016
...Potential for heavy rain and mountain snows continues into
morning...
Severe potential will be shifting northward through the afternoon
as the front lifts northward...and may be largely done by 6 PM.
Wrap around spreads in tonight as the upper low slowly moves
eastward across Colorodo. This will put a steady rain/higher
elevation snow across the area...particularly for the Pikes Peak
region. For now...although rainfall could be moderate at times
tonight through Friday...think that rates are not as likely to
exceed flash flood thresholds on the Waldo burn scar as previously
thought. There certainly could be some enhanced runoff into
fountain creek...but this may end up being more steady rises
rather than a sudden one. The only caveat to this is if a strong
to severe cell hits the Waldo Burn scar this afternoon. If this
happens...then there would be a potential for flash flooding...with
greatest threat before 6 PM. Since cells will be hit or miss early
on...no plans to issue any flash flood watches at this point.
Should see a pretty good band of rain and higher elevation snow
take shape and move eastward across the plains on Friday as the
upper low pulls eastward with UVV associated with upper level
deformation, along with mid level north to northeast flow
impinging on the eastern mountains. Cooling aloft under the
passing low, with H7 temperatures progged between 0C and 4C across
the area into early tomorrow morning, supports snow levels down
to around 9000 feet before lifting back up to at or above 10K
through the day, with scattered showers and thunderstorms area
wide through the afternoon. Current winter weather highlights
still look good with total snow accumulations of over a foot on
top of Pikes Peak and 2 to 4 inches across the rest of Teller
County, with 4 to locally 8 inches across the higher elevations
of the Sawatch and Mosquito Ranges, and the Sangre de Cristo and
Wet Mountains. The passing system sends a cold front across the
Eastern Plains, with breezy north winds and temps below seasonal
averages expected across the area through the day tomorrow.
.LONG TERM...(Friday night through Thursday)
Issued at 325 PM MDT Thu May 26 2016
Saturday-Sunday...Drier westerly flow aloft across the area Saturday
gives way to increasing southwest flow through the day on Sunday
ahead of an embedded disturbance translating across the southern
Rockies through Sunday night. There will be enough residual moisture
to support isolated to scattered showers and storms across the area
Saturday afternoon and evening, with the best coverage over and near
the higher terrain. There remains some model diffecences on
Sunday, through there looks to be a better chance of showers and
storms expected across the area through the afternoon and
evening, with stronger storms possible across the far SE Plains
with a dry line in the vicinity of western Kansas. Temperatures
look to be at or slightly below seasonal averages through the
weekend.
Monday-Thursday...A relatively cool and unsettled weather pattern
remains in the offing through early next week, as another embedded
disturbance translates across the northern and central Rockies
sends a front across the plains on Monday, with cool upslope flow
persisting across the area on Tuesday. This will keep generally
scattered afternoon and evening showers and storms possible
through the period, with temperatures remaining at or slightly
below seasonal averages.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 325 PM MDT Thu May 26 2016
VFR conditions will transition to to MVFR as thunderstorms develop
over the mountains and spread eastward onto the plains this
afternoon through tonight. Strong to severe thunderstorms will be
possible this afternoon after 20-21z for KCOS and KPUB with
erratic wind gusts to 40 kts or higher along with hail...and heavy
rainfall. Winds will shift from the north after thunderstorms
roll through with gusts to 20-30 kts tonight. There may be a lull
in showers for the KCOS terminal before they increase again after
04z with more widespread MVFR CIGS and VIS due to rainfall. PUB
will see stratiform rain and MVFR conditions spread in after 09z.
Winds will increase again from the north at both KCOS and KPUB
Friday morning.
&&
.PUB Watches/Warnings/Advisories...
Winter Weather Advisory until 6 AM MDT Friday for COZ058-060.
Winter Storm Warning until 6 PM MDT Friday for COZ082.
Winter Weather Advisory until noon MDT Friday for COZ073-080.
&&
$$
SHORT TERM...KT/MW
LONG TERM...MW
AVIATION...KT/MW
Area Forecast Discussion
National Weather Service Pueblo CO
1138 AM MDT THU MAY 26 2016
.UPDATE...
Issued at 1023 AM MDT Thu May 26 2016
Models still converging on a farther south position of the cold
front this afternoon which puts more of southeast Colorado under
the threat for severe weather as it lifts back northward. Several
runs now of the HRRR are developing supercell thunderstorms along
the boundary across eastern Las Animas and northern Baca
counties...which track north northeastward through the afternoon.
Pretty good updraft helicity at times with some of these
cells...and they will be in an area of good atmospheric low level helicity
given easterly surface winds beneath southwest flow aloft. Will
have to monitor these for not only a severe thunderstorm
potential...but a tornado potential as well. Other area of concern
will be across El Paso county. Every other run of the HRRR
oscillates between more persistent strong convective regime which
persists through the afternoon...to a scenario of brief severe
convection quickly transitioning over to more stratiform scenario.
Still think there is a window for severe thunderstorm
potential...even an isolated tornado threat through the
afternoon...so forecast leans towards the more convective scenario
for now.
Severe potential will be shifting northward through the afternoon
as the front lifts northward...and may be largely done by 6 PM.
Wrap around spreads in tonight as the upper low slowly moves
eastward across Colorodo. This will put a steady rain/higher
elevation snow across the area...particularly for the Pikes Peak
region. Snow levels down to 9000 feet still look on track as do
highlights across the mountains. Should see a pretty good band of
rain take shape and move eastward across the plains on Friday as
the upper low pulls eastward.
For now...although rainfall could be moderate at times
tonight through Friday...think that rates are not as likely to
exceed flash flood thresholds on the Waldo burn scar as
previously thought. There certainly could be some enhanced runoff
into fountain creek...but this may end up being more steady rises
rather than a sudden one. The only caveat to this is if a strong
to severe cell hits the Waldo Burn scar this afternoon. If this
happens...then there would be a potential for flash flooding...with
greatest threat before 6 PM. Since cells will be hit or miss early
on...no plans to issue any flash flood watches at this point. -KT
&&
.SHORT TERM...(Today and tonight)
Issued at 347 AM MDT Thu May 26 2016
...A POTENTIALLY VERY ACTIVE DAY ACROSS THE FORECAST AREA..
Currently...
Upper closed low which promises to bring active wx to the region
later today and tonight was spinning over nw AZ at 3 am. Over the
immediate area, boundary extended from roughly KSPD to Kim to KPUB
and the banked up along the mtns. North of this boundary winds are
generally east to northeast with dwpts in the 40s...with 50s over
the extreme east. South of this boundary it was much dryer...with
dwpts in the teens and 20s. Low clouds were generally north of
highway 50 mainly in Kiowa county.
Today...
Guidance not in good agreement this morning. shorter range hi res
guidance wants to keep the boundary down towards the Raton Mesa and
moves it only slowly north with time. Other guidance such as the NAM
and GFS move the boundary farther north with time...generally north
of highway 50. The location of this boundary is going to be critical
on where severe thunderstorms develop today. if the boundary remains
farther south...than more of the plains will be under a threat of
severe storms. If the boundary lift north...than less of the region
will be under the threat. As of 3 am...SPC has the svr threat area
mainly north of highway 50. However, as mentioned above...HRRR runs
have been persistent on wanting to keep this boundary down towards
the Raton Mesa, and lifting it north late in the day. Latest runs of
the HRRR does show a few rotating storms on the se Plains later
today.
The next concern for today will be the threat of heavier precip
over the greater Pikes Peak region. All guidance shows heavier
convective precip developing over the Pikes Peak area later this
afternoon, although the guidance has the QPF bullseyes in a variety
of locations. Conceptually...with the closed low moving over the
region and northeasterly 700 mb winds impinging on the Pikes Peak/S
mtn areas, the chance of heavier precip is rather high. The concern
is will the precip fall heavy enough to produce
flooding...especially over the burn scars? Given that the
antecedent conditions are not favorable for flash flooding...I
did not issue any flood hilites for the region, but conditions
will have to be watched closely for the threat of locally heavy
rain over the Waldo burn scar region.
Snow will fall over the highest peaks today. A winter storm warning
is already in effect for Pikes Peak...and have added snow advisories
for the higher elevations of the Wets...N Sangres...and for the C
mtns. The heaviest snow will fall over Pikes Peak.
Tonight...
Severe threat will continue over the far eastern plains, with the
greatest threat along and north of the boundary. Steady precip, with
embedded convection will develop/continue over the greater Pikes
Peak area as strong upslope flow in the lower atmosphere impinges
across this region. it is not out of the question that some areas in
the Pikes Peak area are going to see an inch of liquid...with local
amounts in excess of 2 inches possible. Heavy wet snow will fall
over the highest elevations of both Teller and El Paso counties. I
expect most of the accumulating snow will fall above ~9000 feet.
With the snow levels falling...the threat for flooding over the burn
scar will decrease.
Summarizing...
Severe storms will be possible over the Plains today. The severe
potential will extend includes the I-25 corridor region. I would not
be too surprised if the 1300 UTC SPC DY1 outlook has more of se CO
outlooked for severe weather based on the HRRR output. All severe
convective modes will be possible...with the greatest threat for a
tornado or two along the boundary that will extend across the
Plains. I anticipate a tornado watch will be issued later today for
parts of the plains.
Heavy rains will likely occur across most if not all of the Pikes
Peak region later this afternoon and into tonight. Some convective
heavy rains will likely occur later this afternoon. If one of these
storms develops over the burn scar...than a flash flood threat will
be possible. A flash flood watch may be needed later today for the
burn scar.
heavy snow will fall across the mtns. The heaviest accums will
occur above 9000 feet. The heaviest snow will fall over Pikes Peak.
/Hodanish
.LONG TERM...(Friday through Wednesday)
Issued at 347 AM MDT Thu May 26 2016
...Heavy rain and mountain snows continue Friday morning...
Main concern in the extended will be for Friday morning, as the
upper low tracks straight through southeastern Colorado. Storm looks
fairly dynamic, with h7-h5 flow in the 40-50 Kt range rounding the
low center in the NW quad. Mid level flow will be from the N to
NE...bringing a strong orographic component to the Ern mountain
ranges, and contributing to more widespread moderate to heavy precip
in the 12 through 18Z period Friday. The focus for the heaviest QPF
will be over the southern front range, Wets and Sangres, and the I-
25 corridor. The NAM has another 0.5 inches to inch of precip in
this region Fri morn. Other models not quite as wet, but still in
the 0.25-0.50 inch range. With mid level lapse rates falling rapidly
Fri morning, threat for intense convection will drop, but moderate
steady precip could lead to additional problems for local streams
and poor drainage areas. Snow levels will drop to around 8500-9000
feet Fri morning, then rebound to around 10K feet during the day.
Heavy snow accums likely for Pikes Peak above 11000 feet, and higher
elevations of the West and Sangres. Pikes Peak should see an
additional 4-6 inches Friday, and a couple inches for the other
mountain areas. Total snowfall for Pikes Peak could exceed one
foot. Steady precip will wind down Fri afternoon, but there
should still be widespread showers, particularly over the higher
terrain, through the evening. Temps Friday will be about 15
degrees below average for late May.
After Friday, rest of the forecast period is relatively uneventful,
with daily chances for showers, particularly over the mts, and
temps generally around or slightly below average. Quasi-zonal flow
on Sat will transition to SW flow aloft on Sunday as a weaker low
pressure system begins to move into western CO. This system will
move through late Monday into early Tue, and bring another round of
widespread showers and a few storms to the area. The parent low to
this trough will move through the northern Rockies and High Plains
during the midweek period. The GFS is a bit farther south and
stronger with this system than the ECMWF, and there is a large
ensemble spread by 144 hours and beyond. But it is likely the bulk
of this system will remain to our north. As the trough and
associated cold front passes to the east, the Plains will likely
see another round of showers and storms, some of which could be on
the strong side, in the Tue-Wed time period. Stayed pretty close to
the Blended ensemble-based grids for the latter part of the forecast
period, which progs near to slightly below average temps and low-
sct POPs for the region. Rose
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1133 AM MDT Thu May 26 2016
VFR conditions will transition to to MVFR as thunderstorms develop
over the mountains and spread eastward onto the plains this
afternoon through tonight. Strong to severe thunderstorms will be
possible this afternoon after 20-21z for KCOS and KPUB with
erratic wind gusts to 40 kts or higher along with hail...and heavy
rainfall. Winds will shift from the north after thunderstorms
roll through with gusts to 20-30 kts tonight. There may be a lull
in showers for the KCOS terminal before they increase again after
04z with more widespread MVFR CIGS and VIS due to rainfall. PUB
will see stratiform rain and MVFR conditions spread in after 09z.
Winds will increase again from the north at both KCOS and KPUB
Friday morning.
&&
.PUB Watches/Warnings/Advisories...
Winter Weather Advisory from 3 PM this afternoon to 6 AM MDT
Friday for COZ058-060.
Winter Storm Warning from 3 PM this afternoon to 6 PM MDT Friday
for COZ082.
Winter Weather Advisory from 3 PM this afternoon to noon MDT
Friday for COZ073-080.
&&
$$
UPDATE...KT
SHORT TERM...HODANISH
LONG TERM...ROSE
AVIATION...KT
Area Forecast Discussion
National Weather Service Pueblo CO
1120 PM MDT FRI MAY 27 2016
.SHORT TERM...(This evening through Saturday)
Issued at 319 PM MDT Fri May 27 2016
Rest of today...Upper low over eastern CO and western KS will
continue to pull off to the northeast. Area of showers and
thunderstorms has been developing in area of wrap around...with
most intense cells in southern CO developing across Kiowa county.
High res models continue to show best activity across far northeast
sections of that area through late afternoon and early evening before
activity pulls off to the northeast and diminishes overnight.
Main threat will be local wind gusts to around 50 mph along with
some small hail.
Remainder of the area could see some scattered showers and isolated
embedded thunderstorms this afternoon through early
evening...particularly over the mountains but these too should
diminish with loss of heating. Elsewhere, gusty north to northwest
winds will continue across the plains into the early evening, before
winds weaken overnight.
For tomorrow...weather looks much more quiet with shortwave ridging
aloft. There will still be sufficient moisture for thunderstorms,
particularly in and near the mountains. However, limited
instability, with CAPE values generally around 500 J/KG, storms
will remain on the weaker side, with gusty winds up to 50 mph and
lightning being the primary storm threats. Storms will initiate
over the higher terrain before slowly moving across the plains
during the afternoon and evening hours. High temperatures across
the plains will rebound back into the upper 70s with mid to upper-
60s expected across the high valleys. Overnight, temperatures will
be on the cooler side with lows approaching the freezing mark in
the San Luis Valley.
.LONG TERM...(Saturday night through Friday)
Issued at 319 PM MDT Fri May 27 2016
Saturday night-Sunday night...Drier westerly flow aloft across the
area Saturday gives way to increasing southwest flow Saturday night
and Sunday ahead of an embedded disturbance translating across the
southern Rockies through Sunday night. Some differences in models on
location of this embedded disturbance with the latest NAM and GFS
seemingly overdone with WAA precipitation across the far southeast
plains Saturday night. At any rate, isolated to scattered showers
and thunderstorms across the area Saturday afternoon to diminish
through the evening, though did keep slight pops across the far se
plains through the overnight hours. Increasing UVV and moisture
ahead of the southern Rockies wave looks to bring a better chance of
showers and storms across the area Sunday afternoon and evening,
with stronger storms still possible across the far SE Plains, as lee
troughing across the southeast plains helps dry line across western
Kansas to retrograde. Temperatures look to warm back to around
seasonal averages by Sunday.
Monday-Wednesday...A relatively cool and unsettled weather pattern
remains in the offing through the middle of next week, as more
energy translates across the southern Rockies, with another upper
wave slowly digging across the northern Rockies Monday and into the
central High Plains through Wednesday. There are some differences in
model location and timing of features, though a cold front looks to
move across the plains late Monday night and through the day
Tuesday, supporting the potential for possible severe weather and
locally heavy rainfall Tuesday and Wednesday. Could also see some
more higher elevation snowfall through this period, depending on the
track of the upper level features.
Thursday-Friday...A slow warming and drying trend for late next week
as upper level ridging across the Desert Southwest and Great Basin
is progged to build into the Rockies.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1118 PM MDT Fri May 27 2016
VFR conditions are expected at the terminal forecast sites thru
the next 24 hrs. Some showers/tstms will be possible in the vcnty
of KCOS in the afternoon and evening hours on Sat. KALS and KPUB
could also see some late afternoon/early evening pcpn in the vcnty
but it is very uncertain at this time.
&&
.PUB Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...KT
LONG TERM...MW
AVIATION...28
Area Forecast Discussion
National Weather Service Pueblo CO
319 PM MDT FRI MAY 27 2016
.SHORT TERM...(This evening through Saturday)
Issued at 319 PM MDT Fri May 27 2016
Rest of today...Upper low over eastern CO and western KS will
continue to pull off to the northeast. Area of showers and
thunderstorms has been developing in area of wrap around...with
most intense cells in southern CO developing across Kiowa county.
High res models continue to show best activity across far northeast
sections of that area through late afternoon and early evening before
activity pulls off to the northeast and diminishes overnight.
Main threat will be local wind gusts to around 50 mph along with
some small hail.
Remainder of the area could see some scattered showers and isolated
embedded thunderstorms this afternoon through early
evening...particularly over the mountains but these too should
diminish with loss of heating. Elsewhere, gusty north to northwest
winds will continue across the plains into the early evening, before
winds weaken overnight.
For tomorrow...weather looks much more quiet with shortwave ridging
aloft. There will still be sufficient moisture for thunderstorms,
particularly in and near the mountains. However, limited
instability, with CAPE values generally around 500 J/KG, storms
will remain on the weaker side, with gusty winds up to 50 mph and
lightning being the primary storm threats. Storms will initiate
over the higher terrain before slowly moving across the plains
during the afternoon and evening hours. High temperatures across
the plains will rebound back into the upper 70s with mid to upper-
60s expected across the high valleys. Overnight, temperatures will
be on the cooler side with lows approaching the freezing mark in
the San Luis Valley.
.LONG TERM...(Saturday night through Friday)
Issued at 319 PM MDT Fri May 27 2016
Saturday night-Sunday night...Drier westerly flow aloft across the
area Saturday gives way to increasing southwest flow Saturday night
and Sunday ahead of an embedded disturbance translating across the
southern Rockies through Sunday night. Some differences in models on
location of this embedded disturbance with the latest NAM and GFS
seemingly overdone with WAA precipitation across the far southeast
plains Saturday night. At any rate, isolated to scattered showers
and thunderstorms across the area Saturday afternoon to diminish
through the evening, though did keep slight pops across the far se
plains through the overnight hours. Increasing UVV and moisture
ahead of the southern Rockies wave looks to bring a better chance of
showers and storms across the area Sunday afternoon and evening,
with stronger storms still possible across the far SE Plains, as lee
troughing across the southeast plains helps dry line across western
Kansas to retrograde. Temperatures look to warm back to around
seasonal averages by Sunday.
Monday-Wednesday...A relatively cool and unsettled weather pattern
remains in the offing through the middle of next week, as more
energy translates across the southern Rockies, with another upper
wave slowly digging across the northern Rockies Monday and into the
central High Plains through Wednesday. There are some differences in
model location and timing of features, though a cold front looks to
move across the plains late Monday night and through the day
Tuesday, supporting the potential for possible severe weather and
locally heavy rainfall Tuesday and Wednesday. Could also see some
more higher elevation snowfall through this period, depending on the
track of the upper level features.
Thursday-Friday...A slow warming and drying trend for late next week
as upper level ridging across the Desert Southwest and Great Basin
is progged to build into the Rockies.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 319 PM MDT Fri May 27 2016
VFR conditions are expected at the TAF sites throughout the period.
Winds will continue to remain gusty at KPUB and KCOS through 02Z,
before winds decrease overnight. A few showers will continue to
linger around KPUB and KCOS through about 03Z before activity
diminishes overnight. Showers and thunderstorms will form over the
higher terrain starting around 17-18Z tomorrow afternoon. KALS and
KCOS may see VCTS starting around 20Z.
&&
.PUB Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...KT
LONG TERM...MW
AVIATION...KT
[top]
Area Forecast Discussion
National Weather Service Denver/Boulder CO
1248 PM MDT FRI MAY 27 2016
.UPDATE...
Issued at 1204 pM MDT Fri May 27 2016
The suns heating over the far northeast corner of the state has
allowed for some additional destabilization. May see a stronger
storm east of a line from Sterling to Limon. The main threat from
these storms would be hail up to an inch and possible gusty
outflow winds to 40 mph.
UPDATE Issued at 1041 AM MDT Fri May 27 2016
The band of rain across the eastern plains is decreasing in area
as well as intensity late this morning. The band is slowly moving
west but is expected to continue to weaken. Rainfall rates will
likely be below a tenth of an inch an hour below the band, and
will continue to lessen. As the day`s heating continues, am still
expecting a few thunderstorms to be able to develop this afternoon
across the forecast area. However with weak CAPE but a cooler
airmass, could still see small hail falling out from them.
Downward QG vertical velocities along with drying downsloping
pattern will diminish showers and thunderstorms this evening, with
only a slight chance of them remaining in NW flow over the
mountains. There is still thunderstorms in the forecast this
evening, however conditions don`t look very favorable, may strip
these out later.
&&
.SHORT TERM...(Today and tonight)
Issued at 350 AM MDT Fri May 27 2016
The upper level low will track across southeast Colorado and into
western Kansas today. A deformation band has developed on the back
side of the low. This area of rain should shift east with the low
this morning. Lowered pops for the northern half of the Front
Range. Will keep the higher pops south and across the eastern
plains due to the area of rain. Rainfall will be light to moderate
with additional amounts mostly less than a half inch. Most of the
precipitation has remained east of the mountains and is expected
to stay east, so will cancel the Winter Weather Advisory.
Airmass becomes slightly unstable this afternoon, mainly over the
higher terrain and far northeast corner of the state. Will have
scattered showers and thunderstorms in the forecast for this with
higher pops over the eastern plains where the deformation zone is
expected to be.
Rain showers and thunderstorms are expected to decrease late this
afternoon and evening as the airmass stabilizes and the low moves
east of the state. Will have low pops in the for the evening and
then end them most locations after midnight. There may be a few
stray showers over the mountains and far northeast Colorado after
midnight and will keep slight pops in the forecast.
.LONG TERM...(Saturday through Thursday)
Issued at 350 AM MDT Fri May 27 2016
The Memorial Day weekend should start out dry Saturday morning
with a weak mid-level shortwave ridge over the area and a light
west-northwesterly flow spreading drier and warmer air over the
fcst area. by afternoon some of the models show this ridge nosing
up into the Dakotas and a weak shortwave trough on its heels
passing over the CWA during the late afternoon/early evening
hours. Strong solar heating resulting in steep lapse rates and the
lingering presence of low-level moisture should manage to produce
isolated to scattered showers/t-storms over the Front Range mtns
and higher foothills by early afternoon. Destabilization aloft and
additional heating of the boundary layer may be sufficient to
spark a few late afternoon/evening t-storms on the plains and
Palmer Divide. Potential instability and shear do not appear
adequate to produce strong/deep convective updrafts leading to
severe t-storms. Furthermore qpf guidance indicates the bulk of
the precip that day will fall over higher elevations...and most of
that less than a quarter inch. As for Temperatures on
Saturday...model guidance indicates a 10-12deg f warmup for most
areas. That seems reasonable with the warming aloft and with a few
more hours sunshine.
Sunday may begin about the same with morning sunshine and mild
temperatures. however by mid to late morning a tight lee slope
pressure gradient creates gusty south-southeasterly sfc winds on
the plains according to the NAM...GFS and Canadian models which
then drives increasing amounts of low-level moisture up into
east-central and northeast Colorado. Could see isolated to widely
scattered t-storms forming on the plains by mid-afternoon...but
the stronger convection will probably stay east of the CWA as it
now appears. Meanwhile mountain areas should again see another
round of afternoon and early evening showers/t-storms but probably
with the coverage expected on Saturday since there does not appear
to be any forcing mechanism aloft. Sunday temperatures should
continue to rise by another 3-5 deg f for most locales with mid-to-
upper 70s on the plains.
For Memorial day...models are offering mixed signals. The NAM
shows another shortwave trough swinging over the area during the
day and interacting with a moisture rich sely low-level flow
together with bndry layer cyclongensis across the northeast
corner of the state. This would potentially result in a stormy
afternoon and evening for this area. Whereas...the GFS...ECMWF
and Canadian models indicate a drier day for the CWA with a warm
and dry swly flow aloft. I like a blend of the models here since
I`m not sure the boundary layer will dry out as much as the models
indicate as they all generally indicate sely sfc winds on the
plains. Temperatures on Monday about the same or perhaps a deg or
two lower than the day before.
For the period Tuesday-Thursday...models continue to indicate
troughing over the Rocky Mtn Region and as a result a slight dip
in temperatures and a slightly better chance of afternoon and
evening showers/t-storms. The best chance for this activity
appears to be on Tuesday and Wednesday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1244 PM MDT Fri May 27 2016
A few weak thunderstorms have formed near KDEN, tracking north to
south. With low freezing levels, even weak thunderstorms will have
the ability to produce small hail. At this time, it looks like TS
should stay east of KBJC and KAPA so will keep it out of their
TAFs. Ceilings are expected to range from 5000 to 6000 feet
through 22z except for near 3000 feet in SHRA/TS, then start
improving through the rest of the afternoon and clear out this
evening. Gusty north to northeasterly winds with gusts to 25
knots possible will decrease after 00z and eventually back toward
drainage. Light winds are expected through 18z Saturday.
&&
.BOU Watches/Warnings/Advisories...
None.
&&
$$
UPDATE...Kriederman
SHORT TERM...Meier
LONG TERM...Baker
AVIATION...Kriederman
[top]
Area Forecast Discussion
National Weather Service Grand Junction CO
312 AM MDT FRI MAY 27 2016
.SHORT TERM...(Today through Saturday)
Issued at 311 AM MDT Fri May 27 2016
A few showers continue this morning due to wraparound flow from
the low that brought the rain and storms yesterday with occasional
snow being reported at the highest elevations. These showers will
weaken as the night progresses but not completely end so you may
see a few raindrops for the morning commute along and south of the
I-70 corridor as well as portions of the San Juans.
While a ridge does build in today, plenty of moisture and daytime
heating will allow another day of showers and storms. Intensity
and coverage will be somewhat less since the area of low pressure, and
forcing it provided, will have shifted well to our east. Like
Thursday, convection should start firing around noon and continue
through sunset with some spotty showers continuing through
midnight.
Flow becomes more zonal Saturday as a weak wave moves over the
region allowing another afternoon and evening of unsettled
weather. Models paint precip over the highest terrain which looks
good as steering winds are quite weak during this timeframe.
Outside of those areas, partly cloudy skies are expected with
temperatures finally reaching more normal values.
.LONG TERM...(Saturday night through Thursday)
Issued at 334 PM MDT Thu May 26 2016
The long wave trough will reload along the west coast during the
weekend as the next low pressure disturbance develops over
southern California. The flow over our area will quickly become
southwest again by Sat. This relatively unstable flow will carry
enough moisture to keep afternoon convection in the
forecast, mainly along the mountains.
Models show this low weakening as it gradually tracks east early
in the work week. Also a stronger low center over the Pacific
northwest will shift east. As both of these features head east,
high pressure will develop along the west coast. So continued
mainly mountain convection can be expected each afternoon through
Tue. Then the west coast ridge will strengthen and move into the
Great Basin for warmer and drier conditions midweek and beyond.
Temperatures are expected to be a tad below normal during the
weekend, then right around normal through the first half of the
work week. Temps will then climb to just a tad above normal by
the end of the period.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 311 AM MDT Fri May 27 2016
Mid level clouds continue to hang around this morning with cigs
varying from about 3.5K feet at ASE up to 10K feet at DRO. Cigs
should lift through the morning hours as the low pressure to our
east continues moving in that direction. A few showers will likely
persist though so those TAF sites near and under the showers may see
the lower cigs persist. KASE...KEGE...KTEX...KRIL and KGJT look to
have the best chance for this to occur. vcsh looks safe for those
sites for the next few hours until some clearing occurs. After
18z...more convection is expected though coverage will be less.
Not sold on any one TAF site actually seeing a -tsra on station so
will leave out for now. By 02z...most convection will end though
some stray showers will persist. Even mentioning the convection
and showery precip, still expect mostly vfr conditions today.
&&
.GJT Watches/Warnings/Advisories...
CO...Winter Weather Advisory until 6 AM MDT early this morning for
COZ010-012.
UT...None.
&&
$$
SHORT TERM...TGR
LONG TERM...EH
AVIATION...TGR
Area Forecast Discussion
National Weather Service Pueblo CO
325 PM MDT THU MAY 26 2016
.SHORT TERM...(This evening through Friday)
Issued at 325 PM MDT Thu May 26 2016
...Potential for heavy rain and mountain snows continues into
morning...
Severe potential will be shifting northward through the afternoon
as the front lifts northward...and may be largely done by 6 PM.
Wrap around spreads in tonight as the upper low slowly moves
eastward across Colorodo. This will put a steady rain/higher
elevation snow across the area...particularly for the Pikes Peak
region. For now...although rainfall could be moderate at times
tonight through Friday...think that rates are not as likely to
exceed flash flood thresholds on the Waldo burn scar as previously
thought. There certainly could be some enhanced runoff into
fountain creek...but this may end up being more steady rises
rather than a sudden one. The only caveat to this is if a strong
to severe cell hits the Waldo Burn scar this afternoon. If this
happens...then there would be a potential for flash flooding...with
greatest threat before 6 PM. Since cells will be hit or miss early
on...no plans to issue any flash flood watches at this point.
Should see a pretty good band of rain and higher elevation snow
take shape and move eastward across the plains on Friday as the
upper low pulls eastward with UVV associated with upper level
deformation, along with mid level north to northeast flow
impinging on the eastern mountains. Cooling aloft under the
passing low, with H7 temperatures progged between 0C and 4C across
the area into early tomorrow morning, supports snow levels down
to around 9000 feet before lifting back up to at or above 10K
through the day, with scattered showers and thunderstorms area
wide through the afternoon. Current winter weather highlights
still look good with total snow accumulations of over a foot on
top of Pikes Peak and 2 to 4 inches across the rest of Teller
County, with 4 to locally 8 inches across the higher elevations
of the Sawatch and Mosquito Ranges, and the Sangre de Cristo and
Wet Mountains. The passing system sends a cold front across the
Eastern Plains, with breezy north winds and temps below seasonal
averages expected across the area through the day tomorrow.
.LONG TERM...(Friday night through Thursday)
Issued at 325 PM MDT Thu May 26 2016
Saturday-Sunday...Drier westerly flow aloft across the area Saturday
gives way to increasing southwest flow through the day on Sunday
ahead of an embedded disturbance translating across the southern
Rockies through Sunday night. There will be enough residual moisture
to support isolated to scattered showers and storms across the area
Saturday afternoon and evening, with the best coverage over and near
the higher terrain. There remains some model diffecences on
Sunday, through there looks to be a better chance of showers and
storms expected across the area through the afternoon and
evening, with stronger storms possible across the far SE Plains
with a dry line in the vicinity of western Kansas. Temperatures
look to be at or slightly below seasonal averages through the
weekend.
Monday-Thursday...A relatively cool and unsettled weather pattern
remains in the offing through early next week, as another embedded
disturbance translates across the northern and central Rockies
sends a front across the plains on Monday, with cool upslope flow
persisting across the area on Tuesday. This will keep generally
scattered afternoon and evening showers and storms possible
through the period, with temperatures remaining at or slightly
below seasonal averages.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 325 PM MDT Thu May 26 2016
VFR conditions will transition to to MVFR as thunderstorms develop
over the mountains and spread eastward onto the plains this
afternoon through tonight. Strong to severe thunderstorms will be
possible this afternoon after 20-21z for KCOS and KPUB with
erratic wind gusts to 40 kts or higher along with hail...and heavy
rainfall. Winds will shift from the north after thunderstorms
roll through with gusts to 20-30 kts tonight. There may be a lull
in showers for the KCOS terminal before they increase again after
04z with more widespread MVFR CIGS and VIS due to rainfall. PUB
will see stratiform rain and MVFR conditions spread in after 09z.
Winds will increase again from the north at both KCOS and KPUB
Friday morning.
&&
.PUB Watches/Warnings/Advisories...
Winter Weather Advisory until 6 AM MDT Friday for COZ058-060.
Winter Storm Warning until 6 PM MDT Friday for COZ082.
Winter Weather Advisory until noon MDT Friday for COZ073-080.
&&
$$
SHORT TERM...KT/MW
LONG TERM...MW
AVIATION...KT/MW
Area Forecast Discussion
National Weather Service Pueblo CO
1138 AM MDT THU MAY 26 2016
.UPDATE...
Issued at 1023 AM MDT Thu May 26 2016
Models still converging on a farther south position of the cold
front this afternoon which puts more of southeast Colorado under
the threat for severe weather as it lifts back northward. Several
runs now of the HRRR are developing supercell thunderstorms along
the boundary across eastern Las Animas and northern Baca
counties...which track north northeastward through the afternoon.
Pretty good updraft helicity at times with some of these
cells...and they will be in an area of good atmospheric low level helicity
given easterly surface winds beneath southwest flow aloft. Will
have to monitor these for not only a severe thunderstorm
potential...but a tornado potential as well. Other area of concern
will be across El Paso county. Every other run of the HRRR
oscillates between more persistent strong convective regime which
persists through the afternoon...to a scenario of brief severe
convection quickly transitioning over to more stratiform scenario.
Still think there is a window for severe thunderstorm
potential...even an isolated tornado threat through the
afternoon...so forecast leans towards the more convective scenario
for now.
Severe potential will be shifting northward through the afternoon
as the front lifts northward...and may be largely done by 6 PM.
Wrap around spreads in tonight as the upper low slowly moves
eastward across Colorodo. This will put a steady rain/higher
elevation snow across the area...particularly for the Pikes Peak
region. Snow levels down to 9000 feet still look on track as do
highlights across the mountains. Should see a pretty good band of
rain take shape and move eastward across the plains on Friday as
the upper low pulls eastward.
For now...although rainfall could be moderate at times
tonight through Friday...think that rates are not as likely to
exceed flash flood thresholds on the Waldo burn scar as
previously thought. There certainly could be some enhanced runoff
into fountain creek...but this may end up being more steady rises
rather than a sudden one. The only caveat to this is if a strong
to severe cell hits the Waldo Burn scar this afternoon. If this
happens...then there would be a potential for flash flooding...with
greatest threat before 6 PM. Since cells will be hit or miss early
on...no plans to issue any flash flood watches at this point. -KT
&&
.SHORT TERM...(Today and tonight)
Issued at 347 AM MDT Thu May 26 2016
...A POTENTIALLY VERY ACTIVE DAY ACROSS THE FORECAST AREA..
Currently...
Upper closed low which promises to bring active wx to the region
later today and tonight was spinning over nw AZ at 3 am. Over the
immediate area, boundary extended from roughly KSPD to Kim to KPUB
and the banked up along the mtns. North of this boundary winds are
generally east to northeast with dwpts in the 40s...with 50s over
the extreme east. South of this boundary it was much dryer...with
dwpts in the teens and 20s. Low clouds were generally north of
highway 50 mainly in Kiowa county.
Today...
Guidance not in good agreement this morning. shorter range hi res
guidance wants to keep the boundary down towards the Raton Mesa and
moves it only slowly north with time. Other guidance such as the NAM
and GFS move the boundary farther north with time...generally north
of highway 50. The location of this boundary is going to be critical
on where severe thunderstorms develop today. if the boundary remains
farther south...than more of the plains will be under a threat of
severe storms. If the boundary lift north...than less of the region
will be under the threat. As of 3 am...SPC has the svr threat area
mainly north of highway 50. However, as mentioned above...HRRR runs
have been persistent on wanting to keep this boundary down towards
the Raton Mesa, and lifting it north late in the day. Latest runs of
the HRRR does show a few rotating storms on the se Plains later
today.
The next concern for today will be the threat of heavier precip
over the greater Pikes Peak region. All guidance shows heavier
convective precip developing over the Pikes Peak area later this
afternoon, although the guidance has the QPF bullseyes in a variety
of locations. Conceptually...with the closed low moving over the
region and northeasterly 700 mb winds impinging on the Pikes Peak/S
mtn areas, the chance of heavier precip is rather high. The concern
is will the precip fall heavy enough to produce
flooding...especially over the burn scars? Given that the
antecedent conditions are not favorable for flash flooding...I
did not issue any flood hilites for the region, but conditions
will have to be watched closely for the threat of locally heavy
rain over the Waldo burn scar region.
Snow will fall over the highest peaks today. A winter storm warning
is already in effect for Pikes Peak...and have added snow advisories
for the higher elevations of the Wets...N Sangres...and for the C
mtns. The heaviest snow will fall over Pikes Peak.
Tonight...
Severe threat will continue over the far eastern plains, with the
greatest threat along and north of the boundary. Steady precip, with
embedded convection will develop/continue over the greater Pikes
Peak area as strong upslope flow in the lower atmosphere impinges
across this region. it is not out of the question that some areas in
the Pikes Peak area are going to see an inch of liquid...with local
amounts in excess of 2 inches possible. Heavy wet snow will fall
over the highest elevations of both Teller and El Paso counties. I
expect most of the accumulating snow will fall above ~9000 feet.
With the snow levels falling...the threat for flooding over the burn
scar will decrease.
Summarizing...
Severe storms will be possible over the Plains today. The severe
potential will extend includes the I-25 corridor region. I would not
be too surprised if the 1300 UTC SPC DY1 outlook has more of se CO
outlooked for severe weather based on the HRRR output. All severe
convective modes will be possible...with the greatest threat for a
tornado or two along the boundary that will extend across the
Plains. I anticipate a tornado watch will be issued later today for
parts of the plains.
Heavy rains will likely occur across most if not all of the Pikes
Peak region later this afternoon and into tonight. Some convective
heavy rains will likely occur later this afternoon. If one of these
storms develops over the burn scar...than a flash flood threat will
be possible. A flash flood watch may be needed later today for the
burn scar.
heavy snow will fall across the mtns. The heaviest accums will
occur above 9000 feet. The heaviest snow will fall over Pikes Peak.
/Hodanish
.LONG TERM...(Friday through Wednesday)
Issued at 347 AM MDT Thu May 26 2016
...Heavy rain and mountain snows continue Friday morning...
Main concern in the extended will be for Friday morning, as the
upper low tracks straight through southeastern Colorado. Storm looks
fairly dynamic, with h7-h5 flow in the 40-50 Kt range rounding the
low center in the NW quad. Mid level flow will be from the N to
NE...bringing a strong orographic component to the Ern mountain
ranges, and contributing to more widespread moderate to heavy precip
in the 12 through 18Z period Friday. The focus for the heaviest QPF
will be over the southern front range, Wets and Sangres, and the I-
25 corridor. The NAM has another 0.5 inches to inch of precip in
this region Fri morn. Other models not quite as wet, but still in
the 0.25-0.50 inch range. With mid level lapse rates falling rapidly
Fri morning, threat for intense convection will drop, but moderate
steady precip could lead to additional problems for local streams
and poor drainage areas. Snow levels will drop to around 8500-9000
feet Fri morning, then rebound to around 10K feet during the day.
Heavy snow accums likely for Pikes Peak above 11000 feet, and higher
elevations of the West and Sangres. Pikes Peak should see an
additional 4-6 inches Friday, and a couple inches for the other
mountain areas. Total snowfall for Pikes Peak could exceed one
foot. Steady precip will wind down Fri afternoon, but there
should still be widespread showers, particularly over the higher
terrain, through the evening. Temps Friday will be about 15
degrees below average for late May.
After Friday, rest of the forecast period is relatively uneventful,
with daily chances for showers, particularly over the mts, and
temps generally around or slightly below average. Quasi-zonal flow
on Sat will transition to SW flow aloft on Sunday as a weaker low
pressure system begins to move into western CO. This system will
move through late Monday into early Tue, and bring another round of
widespread showers and a few storms to the area. The parent low to
this trough will move through the northern Rockies and High Plains
during the midweek period. The GFS is a bit farther south and
stronger with this system than the ECMWF, and there is a large
ensemble spread by 144 hours and beyond. But it is likely the bulk
of this system will remain to our north. As the trough and
associated cold front passes to the east, the Plains will likely
see another round of showers and storms, some of which could be on
the strong side, in the Tue-Wed time period. Stayed pretty close to
the Blended ensemble-based grids for the latter part of the forecast
period, which progs near to slightly below average temps and low-
sct POPs for the region. Rose
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1133 AM MDT Thu May 26 2016
VFR conditions will transition to to MVFR as thunderstorms develop
over the mountains and spread eastward onto the plains this
afternoon through tonight. Strong to severe thunderstorms will be
possible this afternoon after 20-21z for KCOS and KPUB with
erratic wind gusts to 40 kts or higher along with hail...and heavy
rainfall. Winds will shift from the north after thunderstorms
roll through with gusts to 20-30 kts tonight. There may be a lull
in showers for the KCOS terminal before they increase again after
04z with more widespread MVFR CIGS and VIS due to rainfall. PUB
will see stratiform rain and MVFR conditions spread in after 09z.
Winds will increase again from the north at both KCOS and KPUB
Friday morning.
&&
.PUB Watches/Warnings/Advisories...
Winter Weather Advisory from 3 PM this afternoon to 6 AM MDT
Friday for COZ058-060.
Winter Storm Warning from 3 PM this afternoon to 6 PM MDT Friday
for COZ082.
Winter Weather Advisory from 3 PM this afternoon to noon MDT
Friday for COZ073-080.
&&
$$
UPDATE...KT
SHORT TERM...HODANISH
LONG TERM...ROSE
AVIATION...KT
Area Forecast Discussion
National Weather Service Denver/Boulder CO
355 AM MDT SAT MAY 28 2016
.SHORT TERM...(Today and tonight)
Issued at 350 AM MDT Sat May 28 2016
The upper level low that brought cool conditions and showers
yesterday has moved into Nebraska. Behind it, a weak ridge in a
westerly flow aloft will be over Colorado today. Airmass is drier
and will result in mostly sunny skies for this morning. It will
become a little unstable this afternoon with CAPEs up to 500 J/kg.
Models in decent agreement with scattered thunderstorms forming
this afternoon over the higher terrain, including the Cheyenne
Ridge and Palmer Divide. A few of these storms are expect to
survive off the higher terrain. Weak instability and little shear
will keep storms well below severe threshold today. The storms
will end this evening as the airmass stabilizes. With the
increased sunshine today, highs will climb into the upper 60s to
lower 70s. Still a little below normal for this time of year.
.LONG TERM...(Sunday through Friday)
Issued at 350 AM MDT Sat May 28 2016
The upper ridge mentioned above remains positioned over Colorado
on Sunday but in a weakened state due to a series of weak
pertabations passing over the state in west-southwesterly mid-
level flow. The NAM continues to be more bullish with these
features particularly with the wave moving off the Front Range
Sunday afternoon. Height falls with this wave together with stg
solar heating produce pressure falls along the Front Range which
in turn strengthens the southeasterly gradient wind on the plains
through the afternoon. In doing so..models show low-level
moisture/lower 50s dewpoints/ feeding northwestward up into nern
Colorado which aids in producing bndry layer CAPES in the
500-1500 j/kg range in areas roughly east of a Briggsdale-to-
Kiowa line by mid-afternoon. Main axis of this elevated instability
and moisture appears lies across northern Lincoln and Elbert
Counties...but in time shifts north across the northeast corner of
the state with passage of the shortwave energy. The threat for
severe storms appears marginal at best at this time and mainly
acrs far sern sections of the CWA late afternoon/early evening.
Large hail being the main threat. Otherwise temperatures Sunday
look slightly warmer with max readings near average for most
locations. Overnight...shower and t-storm chances decrease from
west to east with drier southwesterly flow in place.
by Memorial Day...the upper ridge shift east of the area allowing
a west-northwest flow aloft to usher in another batch of mid-level
energy and moisture for another round of afternoon and evening
convection. That`s after a dry and mild morning. Temperatures on
Monday expected to be near to slightly warmer than those on
Sunday. Could see showers and t-storms lingering well into the
night esply on the plains with a sfc cold front forecast to slide
south acrs nern Colorado during the pre-dawn hours. For that
reason could see a jump in storm coverage on the far plains after
midnight.
Tuesday and Wednesday turn cooler with long wave upper trough
passing over the northern and central Rocky Mtn region. Temps as
much as 10-15 degs cooler with plenty of cloud cover along and
east of the Front Range on Tuesday with anticyclonic upslope flow.
Showers chances also higher but cooler temps and cloud cover
should keep t-storm formation down on the plains. Wednesday dries
out but northwest flow on the back side of the departing trough
will hold temps several degrees below average.
by Thursday and Friday...warmer and drier conditions should
return the forecast region with the strong upper ridge over the
Great Basin moving toward Colorado. Should see temp near to aboveaverage
by the end of the week and the chance for precip near zero for
most locations.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 350 AM MDT Sat May 28 2016
VFR conditions are expected to persist through the forecast
period. Winds will be southerly, with a slight shift to the
southeast after 18z. Airmass becomes slightly unstable this
afternoon. Scattered thunderstorms are expected to form over the
higher terrain after 18z. A few of these are expected to move off
the higher terrain and across the plains. There will a slight
chance one of these storms impact an airport. If one does, brief
heavy rain and wind gusts to 30 knots will be possible for a
short time. For now, will not mention TS in the TAFs since the
chances are low. May go with a VCTS with the 12z TAFs if chances
increase a little.
&&
.BOU Watches/Warnings/Advisories...
None.
&&
$$
SHORT TERM...Meier
LONG TERM...Baker
AVIATION...Meier
[top]
Area Forecast Discussion
National Weather Service Pueblo CO
1120 PM MDT FRI MAY 27 2016
.SHORT TERM...(This evening through Saturday)
Issued at 319 PM MDT Fri May 27 2016
Rest of today...Upper low over eastern CO and western KS will
continue to pull off to the northeast. Area of showers and
thunderstorms has been developing in area of wrap around...with
most intense cells in southern CO developing across Kiowa county.
High res models continue to show best activity across far northeast
sections of that area through late afternoon and early evening before
activity pulls off to the northeast and diminishes overnight.
Main threat will be local wind gusts to around 50 mph along with
some small hail.
Remainder of the area could see some scattered showers and isolated
embedded thunderstorms this afternoon through early
evening...particularly over the mountains but these too should
diminish with loss of heating. Elsewhere, gusty north to northwest
winds will continue across the plains into the early evening, before
winds weaken overnight.
For tomorrow...weather looks much more quiet with shortwave ridging
aloft. There will still be sufficient moisture for thunderstorms,
particularly in and near the mountains. However, limited
instability, with CAPE values generally around 500 J/KG, storms
will remain on the weaker side, with gusty winds up to 50 mph and
lightning being the primary storm threats. Storms will initiate
over the higher terrain before slowly moving across the plains
during the afternoon and evening hours. High temperatures across
the plains will rebound back into the upper 70s with mid to upper-
60s expected across the high valleys. Overnight, temperatures will
be on the cooler side with lows approaching the freezing mark in
the San Luis Valley.
.LONG TERM...(Saturday night through Friday)
Issued at 319 PM MDT Fri May 27 2016
Saturday night-Sunday night...Drier westerly flow aloft across the
area Saturday gives way to increasing southwest flow Saturday night
and Sunday ahead of an embedded disturbance translating across the
southern Rockies through Sunday night. Some differences in models on
location of this embedded disturbance with the latest NAM and GFS
seemingly overdone with WAA precipitation across the far southeast
plains Saturday night. At any rate, isolated to scattered showers
and thunderstorms across the area Saturday afternoon to diminish
through the evening, though did keep slight pops across the far se
plains through the overnight hours. Increasing UVV and moisture
ahead of the southern Rockies wave looks to bring a better chance of
showers and storms across the area Sunday afternoon and evening,
with stronger storms still possible across the far SE Plains, as lee
troughing across the southeast plains helps dry line across western
Kansas to retrograde. Temperatures look to warm back to around
seasonal averages by Sunday.
Monday-Wednesday...A relatively cool and unsettled weather pattern
remains in the offing through the middle of next week, as more
energy translates across the southern Rockies, with another upper
wave slowly digging across the northern Rockies Monday and into the
central High Plains through Wednesday. There are some differences in
model location and timing of features, though a cold front looks to
move across the plains late Monday night and through the day
Tuesday, supporting the potential for possible severe weather and
locally heavy rainfall Tuesday and Wednesday. Could also see some
more higher elevation snowfall through this period, depending on the
track of the upper level features.
Thursday-Friday...A slow warming and drying trend for late next week
as upper level ridging across the Desert Southwest and Great Basin
is progged to build into the Rockies.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1118 PM MDT Fri May 27 2016
VFR conditions are expected at the terminal forecast sites thru
the next 24 hrs. Some showers/tstms will be possible in the vcnty
of KCOS in the afternoon and evening hours on Sat. KALS and KPUB
could also see some late afternoon/early evening pcpn in the vcnty
but it is very uncertain at this time.
&&
.PUB Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...KT
LONG TERM...MW
AVIATION...28
Area Forecast Discussion
National Weather Service Pueblo CO
319 PM MDT FRI MAY 27 2016
.SHORT TERM...(This evening through Saturday)
Issued at 319 PM MDT Fri May 27 2016
Rest of today...Upper low over eastern CO and western KS will
continue to pull off to the northeast. Area of showers and
thunderstorms has been developing in area of wrap around...with
most intense cells in southern CO developing across Kiowa county.
High res models continue to show best activity across far northeast
sections of that area through late afternoon and early evening before
activity pulls off to the northeast and diminishes overnight.
Main threat will be local wind gusts to around 50 mph along with
some small hail.
Remainder of the area could see some scattered showers and isolated
embedded thunderstorms this afternoon through early
evening...particularly over the mountains but these too should
diminish with loss of heating. Elsewhere, gusty north to northwest
winds will continue across the plains into the early evening, before
winds weaken overnight.
For tomorrow...weather looks much more quiet with shortwave ridging
aloft. There will still be sufficient moisture for thunderstorms,
particularly in and near the mountains. However, limited
instability, with CAPE values generally around 500 J/KG, storms
will remain on the weaker side, with gusty winds up to 50 mph and
lightning being the primary storm threats. Storms will initiate
over the higher terrain before slowly moving across the plains
during the afternoon and evening hours. High temperatures across
the plains will rebound back into the upper 70s with mid to upper-
60s expected across the high valleys. Overnight, temperatures will
be on the cooler side with lows approaching the freezing mark in
the San Luis Valley.
.LONG TERM...(Saturday night through Friday)
Issued at 319 PM MDT Fri May 27 2016
Saturday night-Sunday night...Drier westerly flow aloft across the
area Saturday gives way to increasing southwest flow Saturday night
and Sunday ahead of an embedded disturbance translating across the
southern Rockies through Sunday night. Some differences in models on
location of this embedded disturbance with the latest NAM and GFS
seemingly overdone with WAA precipitation across the far southeast
plains Saturday night. At any rate, isolated to scattered showers
and thunderstorms across the area Saturday afternoon to diminish
through the evening, though did keep slight pops across the far se
plains through the overnight hours. Increasing UVV and moisture
ahead of the southern Rockies wave looks to bring a better chance of
showers and storms across the area Sunday afternoon and evening,
with stronger storms still possible across the far SE Plains, as lee
troughing across the southeast plains helps dry line across western
Kansas to retrograde. Temperatures look to warm back to around
seasonal averages by Sunday.
Monday-Wednesday...A relatively cool and unsettled weather pattern
remains in the offing through the middle of next week, as more
energy translates across the southern Rockies, with another upper
wave slowly digging across the northern Rockies Monday and into the
central High Plains through Wednesday. There are some differences in
model location and timing of features, though a cold front looks to
move across the plains late Monday night and through the day
Tuesday, supporting the potential for possible severe weather and
locally heavy rainfall Tuesday and Wednesday. Could also see some
more higher elevation snowfall through this period, depending on the
track of the upper level features.
Thursday-Friday...A slow warming and drying trend for late next week
as upper level ridging across the Desert Southwest and Great Basin
is progged to build into the Rockies.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 319 PM MDT Fri May 27 2016
VFR conditions are expected at the TAF sites throughout the period.
Winds will continue to remain gusty at KPUB and KCOS through 02Z,
before winds decrease overnight. A few showers will continue to
linger around KPUB and KCOS through about 03Z before activity
diminishes overnight. Showers and thunderstorms will form over the
higher terrain starting around 17-18Z tomorrow afternoon. KALS and
KCOS may see VCTS starting around 20Z.
&&
.PUB Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...KT
LONG TERM...MW
AVIATION...KT
Area Forecast Discussion
National Weather Service Denver/Boulder CO
1248 PM MDT FRI MAY 27 2016
.UPDATE...
Issued at 1204 pM MDT Fri May 27 2016
The suns heating over the far northeast corner of the state has
allowed for some additional destabilization. May see a stronger
storm east of a line from Sterling to Limon. The main threat from
these storms would be hail up to an inch and possible gusty
outflow winds to 40 mph.
UPDATE Issued at 1041 AM MDT Fri May 27 2016
The band of rain across the eastern plains is decreasing in area
as well as intensity late this morning. The band is slowly moving
west but is expected to continue to weaken. Rainfall rates will
likely be below a tenth of an inch an hour below the band, and
will continue to lessen. As the day`s heating continues, am still
expecting a few thunderstorms to be able to develop this afternoon
across the forecast area. However with weak CAPE but a cooler
airmass, could still see small hail falling out from them.
Downward QG vertical velocities along with drying downsloping
pattern will diminish showers and thunderstorms this evening, with
only a slight chance of them remaining in NW flow over the
mountains. There is still thunderstorms in the forecast this
evening, however conditions don`t look very favorable, may strip
these out later.
&&
.SHORT TERM...(Today and tonight)
Issued at 350 AM MDT Fri May 27 2016
The upper level low will track across southeast Colorado and into
western Kansas today. A deformation band has developed on the back
side of the low. This area of rain should shift east with the low
this morning. Lowered pops for the northern half of the Front
Range. Will keep the higher pops south and across the eastern
plains due to the area of rain. Rainfall will be light to moderate
with additional amounts mostly less than a half inch. Most of the
precipitation has remained east of the mountains and is expected
to stay east, so will cancel the Winter Weather Advisory.
Airmass becomes slightly unstable this afternoon, mainly over the
higher terrain and far northeast corner of the state. Will have
scattered showers and thunderstorms in the forecast for this with
higher pops over the eastern plains where the deformation zone is
expected to be.
Rain showers and thunderstorms are expected to decrease late this
afternoon and evening as the airmass stabilizes and the low moves
east of the state. Will have low pops in the for the evening and
then end them most locations after midnight. There may be a few
stray showers over the mountains and far northeast Colorado after
midnight and will keep slight pops in the forecast.
.LONG TERM...(Saturday through Thursday)
Issued at 350 AM MDT Fri May 27 2016
The Memorial Day weekend should start out dry Saturday morning
with a weak mid-level shortwave ridge over the area and a light
west-northwesterly flow spreading drier and warmer air over the
fcst area. by afternoon some of the models show this ridge nosing
up into the Dakotas and a weak shortwave trough on its heels
passing over the CWA during the late afternoon/early evening
hours. Strong solar heating resulting in steep lapse rates and the
lingering presence of low-level moisture should manage to produce
isolated to scattered showers/t-storms over the Front Range mtns
and higher foothills by early afternoon. Destabilization aloft and
additional heating of the boundary layer may be sufficient to
spark a few late afternoon/evening t-storms on the plains and
Palmer Divide. Potential instability and shear do not appear
adequate to produce strong/deep convective updrafts leading to
severe t-storms. Furthermore qpf guidance indicates the bulk of
the precip that day will fall over higher elevations...and most of
that less than a quarter inch. As for Temperatures on
Saturday...model guidance indicates a 10-12deg f warmup for most
areas. That seems reasonable with the warming aloft and with a few
more hours sunshine.
Sunday may begin about the same with morning sunshine and mild
temperatures. however by mid to late morning a tight lee slope
pressure gradient creates gusty south-southeasterly sfc winds on
the plains according to the NAM...GFS and Canadian models which
then drives increasing amounts of low-level moisture up into
east-central and northeast Colorado. Could see isolated to widely
scattered t-storms forming on the plains by mid-afternoon...but
the stronger convection will probably stay east of the CWA as it
now appears. Meanwhile mountain areas should again see another
round of afternoon and early evening showers/t-storms but probably
with the coverage expected on Saturday since there does not appear
to be any forcing mechanism aloft. Sunday temperatures should
continue to rise by another 3-5 deg f for most locales with mid-to-
upper 70s on the plains.
For Memorial day...models are offering mixed signals. The NAM
shows another shortwave trough swinging over the area during the
day and interacting with a moisture rich sely low-level flow
together with bndry layer cyclongensis across the northeast
corner of the state. This would potentially result in a stormy
afternoon and evening for this area. Whereas...the GFS...ECMWF
and Canadian models indicate a drier day for the CWA with a warm
and dry swly flow aloft. I like a blend of the models here since
I`m not sure the boundary layer will dry out as much as the models
indicate as they all generally indicate sely sfc winds on the
plains. Temperatures on Monday about the same or perhaps a deg or
two lower than the day before.
For the period Tuesday-Thursday...models continue to indicate
troughing over the Rocky Mtn Region and as a result a slight dip
in temperatures and a slightly better chance of afternoon and
evening showers/t-storms. The best chance for this activity
appears to be on Tuesday and Wednesday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1244 PM MDT Fri May 27 2016
A few weak thunderstorms have formed near KDEN, tracking north to
south. With low freezing levels, even weak thunderstorms will have
the ability to produce small hail. At this time, it looks like TS
should stay east of KBJC and KAPA so will keep it out of their
TAFs. Ceilings are expected to range from 5000 to 6000 feet
through 22z except for near 3000 feet in SHRA/TS, then start
improving through the rest of the afternoon and clear out this
evening. Gusty north to northeasterly winds with gusts to 25
knots possible will decrease after 00z and eventually back toward
drainage. Light winds are expected through 18z Saturday.
&&
.BOU Watches/Warnings/Advisories...
None.
&&
$$
UPDATE...Kriederman
SHORT TERM...Meier
LONG TERM...Baker
AVIATION...Kriederman
[top]
Area Forecast Discussion
National Weather Service Grand Junction CO
312 AM MDT FRI MAY 27 2016
.SHORT TERM...(Today through Saturday)
Issued at 311 AM MDT Fri May 27 2016
A few showers continue this morning due to wraparound flow from
the low that brought the rain and storms yesterday with occasional
snow being reported at the highest elevations. These showers will
weaken as the night progresses but not completely end so you may
see a few raindrops for the morning commute along and south of the
I-70 corridor as well as portions of the San Juans.
While a ridge does build in today, plenty of moisture and daytime
heating will allow another day of showers and storms. Intensity
and coverage will be somewhat less since the area of low pressure, and
forcing it provided, will have shifted well to our east. Like
Thursday, convection should start firing around noon and continue
through sunset with some spotty showers continuing through
midnight.
Flow becomes more zonal Saturday as a weak wave moves over the
region allowing another afternoon and evening of unsettled
weather. Models paint precip over the highest terrain which looks
good as steering winds are quite weak during this timeframe.
Outside of those areas, partly cloudy skies are expected with
temperatures finally reaching more normal values.
.LONG TERM...(Saturday night through Thursday)
Issued at 334 PM MDT Thu May 26 2016
The long wave trough will reload along the west coast during the
weekend as the next low pressure disturbance develops over
southern California. The flow over our area will quickly become
southwest again by Sat. This relatively unstable flow will carry
enough moisture to keep afternoon convection in the
forecast, mainly along the mountains.
Models show this low weakening as it gradually tracks east early
in the work week. Also a stronger low center over the Pacific
northwest will shift east. As both of these features head east,
high pressure will develop along the west coast. So continued
mainly mountain convection can be expected each afternoon through
Tue. Then the west coast ridge will strengthen and move into the
Great Basin for warmer and drier conditions midweek and beyond.
Temperatures are expected to be a tad below normal during the
weekend, then right around normal through the first half of the
work week. Temps will then climb to just a tad above normal by
the end of the period.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 311 AM MDT Fri May 27 2016
Mid level clouds continue to hang around this morning with cigs
varying from about 3.5K feet at ASE up to 10K feet at DRO. Cigs
should lift through the morning hours as the low pressure to our
east continues moving in that direction. A few showers will likely
persist though so those TAF sites near and under the showers may see
the lower cigs persist. KASE...KEGE...KTEX...KRIL and KGJT look to
have the best chance for this to occur. vcsh looks safe for those
sites for the next few hours until some clearing occurs. After
18z...more convection is expected though coverage will be less.
Not sold on any one TAF site actually seeing a -tsra on station so
will leave out for now. By 02z...most convection will end though
some stray showers will persist. Even mentioning the convection
and showery precip, still expect mostly vfr conditions today.
&&
.GJT Watches/Warnings/Advisories...
CO...Winter Weather Advisory until 6 AM MDT early this morning for
COZ010-012.
UT...None.
&&
$$
SHORT TERM...TGR
LONG TERM...EH
AVIATION...TGR
Area Forecast Discussion
National Weather Service Pueblo CO
325 PM MDT THU MAY 26 2016
.SHORT TERM...(This evening through Friday)
Issued at 325 PM MDT Thu May 26 2016
...Potential for heavy rain and mountain snows continues into
morning...
Severe potential will be shifting northward through the afternoon
as the front lifts northward...and may be largely done by 6 PM.
Wrap around spreads in tonight as the upper low slowly moves
eastward across Colorodo. This will put a steady rain/higher
elevation snow across the area...particularly for the Pikes Peak
region. For now...although rainfall could be moderate at times
tonight through Friday...think that rates are not as likely to
exceed flash flood thresholds on the Waldo burn scar as previously
thought. There certainly could be some enhanced runoff into
fountain creek...but this may end up being more steady rises
rather than a sudden one. The only caveat to this is if a strong
to severe cell hits the Waldo Burn scar this afternoon. If this
happens...then there would be a potential for flash flooding...with
greatest threat before 6 PM. Since cells will be hit or miss early
on...no plans to issue any flash flood watches at this point.
Should see a pretty good band of rain and higher elevation snow
take shape and move eastward across the plains on Friday as the
upper low pulls eastward with UVV associated with upper level
deformation, along with mid level north to northeast flow
impinging on the eastern mountains. Cooling aloft under the
passing low, with H7 temperatures progged between 0C and 4C across
the area into early tomorrow morning, supports snow levels down
to around 9000 feet before lifting back up to at or above 10K
through the day, with scattered showers and thunderstorms area
wide through the afternoon. Current winter weather highlights
still look good with total snow accumulations of over a foot on
top of Pikes Peak and 2 to 4 inches across the rest of Teller
County, with 4 to locally 8 inches across the higher elevations
of the Sawatch and Mosquito Ranges, and the Sangre de Cristo and
Wet Mountains. The passing system sends a cold front across the
Eastern Plains, with breezy north winds and temps below seasonal
averages expected across the area through the day tomorrow.
.LONG TERM...(Friday night through Thursday)
Issued at 325 PM MDT Thu May 26 2016
Saturday-Sunday...Drier westerly flow aloft across the area Saturday
gives way to increasing southwest flow through the day on Sunday
ahead of an embedded disturbance translating across the southern
Rockies through Sunday night. There will be enough residual moisture
to support isolated to scattered showers and storms across the area
Saturday afternoon and evening, with the best coverage over and near
the higher terrain. There remains some model diffecences on
Sunday, through there looks to be a better chance of showers and
storms expected across the area through the afternoon and
evening, with stronger storms possible across the far SE Plains
with a dry line in the vicinity of western Kansas. Temperatures
look to be at or slightly below seasonal averages through the
weekend.
Monday-Thursday...A relatively cool and unsettled weather pattern
remains in the offing through early next week, as another embedded
disturbance translates across the northern and central Rockies
sends a front across the plains on Monday, with cool upslope flow
persisting across the area on Tuesday. This will keep generally
scattered afternoon and evening showers and storms possible
through the period, with temperatures remaining at or slightly
below seasonal averages.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 325 PM MDT Thu May 26 2016
VFR conditions will transition to to MVFR as thunderstorms develop
over the mountains and spread eastward onto the plains this
afternoon through tonight. Strong to severe thunderstorms will be
possible this afternoon after 20-21z for KCOS and KPUB with
erratic wind gusts to 40 kts or higher along with hail...and heavy
rainfall. Winds will shift from the north after thunderstorms
roll through with gusts to 20-30 kts tonight. There may be a lull
in showers for the KCOS terminal before they increase again after
04z with more widespread MVFR CIGS and VIS due to rainfall. PUB
will see stratiform rain and MVFR conditions spread in after 09z.
Winds will increase again from the north at both KCOS and KPUB
Friday morning.
&&
.PUB Watches/Warnings/Advisories...
Winter Weather Advisory until 6 AM MDT Friday for COZ058-060.
Winter Storm Warning until 6 PM MDT Friday for COZ082.
Winter Weather Advisory until noon MDT Friday for COZ073-080.
&&
$$
SHORT TERM...KT/MW
LONG TERM...MW
AVIATION...KT/MW
Area Forecast Discussion
National Weather Service Pueblo CO
1138 AM MDT THU MAY 26 2016
.UPDATE...
Issued at 1023 AM MDT Thu May 26 2016
Models still converging on a farther south position of the cold
front this afternoon which puts more of southeast Colorado under
the threat for severe weather as it lifts back northward. Several
runs now of the HRRR are developing supercell thunderstorms along
the boundary across eastern Las Animas and northern Baca
counties...which track north northeastward through the afternoon.
Pretty good updraft helicity at times with some of these
cells...and they will be in an area of good atmospheric low level helicity
given easterly surface winds beneath southwest flow aloft. Will
have to monitor these for not only a severe thunderstorm
potential...but a tornado potential as well. Other area of concern
will be across El Paso county. Every other run of the HRRR
oscillates between more persistent strong convective regime which
persists through the afternoon...to a scenario of brief severe
convection quickly transitioning over to more stratiform scenario.
Still think there is a window for severe thunderstorm
potential...even an isolated tornado threat through the
afternoon...so forecast leans towards the more convective scenario
for now.
Severe potential will be shifting northward through the afternoon
as the front lifts northward...and may be largely done by 6 PM.
Wrap around spreads in tonight as the upper low slowly moves
eastward across Colorodo. This will put a steady rain/higher
elevation snow across the area...particularly for the Pikes Peak
region. Snow levels down to 9000 feet still look on track as do
highlights across the mountains. Should see a pretty good band of
rain take shape and move eastward across the plains on Friday as
the upper low pulls eastward.
For now...although rainfall could be moderate at times
tonight through Friday...think that rates are not as likely to
exceed flash flood thresholds on the Waldo burn scar as
previously thought. There certainly could be some enhanced runoff
into fountain creek...but this may end up being more steady rises
rather than a sudden one. The only caveat to this is if a strong
to severe cell hits the Waldo Burn scar this afternoon. If this
happens...then there would be a potential for flash flooding...with
greatest threat before 6 PM. Since cells will be hit or miss early
on...no plans to issue any flash flood watches at this point. -KT
&&
.SHORT TERM...(Today and tonight)
Issued at 347 AM MDT Thu May 26 2016
...A POTENTIALLY VERY ACTIVE DAY ACROSS THE FORECAST AREA..
Currently...
Upper closed low which promises to bring active wx to the region
later today and tonight was spinning over nw AZ at 3 am. Over the
immediate area, boundary extended from roughly KSPD to Kim to KPUB
and the banked up along the mtns. North of this boundary winds are
generally east to northeast with dwpts in the 40s...with 50s over
the extreme east. South of this boundary it was much dryer...with
dwpts in the teens and 20s. Low clouds were generally north of
highway 50 mainly in Kiowa county.
Today...
Guidance not in good agreement this morning. shorter range hi res
guidance wants to keep the boundary down towards the Raton Mesa and
moves it only slowly north with time. Other guidance such as the NAM
and GFS move the boundary farther north with time...generally north
of highway 50. The location of this boundary is going to be critical
on where severe thunderstorms develop today. if the boundary remains
farther south...than more of the plains will be under a threat of
severe storms. If the boundary lift north...than less of the region
will be under the threat. As of 3 am...SPC has the svr threat area
mainly north of highway 50. However, as mentioned above...HRRR runs
have been persistent on wanting to keep this boundary down towards
the Raton Mesa, and lifting it north late in the day. Latest runs of
the HRRR does show a few rotating storms on the se Plains later
today.
The next concern for today will be the threat of heavier precip
over the greater Pikes Peak region. All guidance shows heavier
convective precip developing over the Pikes Peak area later this
afternoon, although the guidance has the QPF bullseyes in a variety
of locations. Conceptually...with the closed low moving over the
region and northeasterly 700 mb winds impinging on the Pikes Peak/S
mtn areas, the chance of heavier precip is rather high. The concern
is will the precip fall heavy enough to produce
flooding...especially over the burn scars? Given that the
antecedent conditions are not favorable for flash flooding...I
did not issue any flood hilites for the region, but conditions
will have to be watched closely for the threat of locally heavy
rain over the Waldo burn scar region.
Snow will fall over the highest peaks today. A winter storm warning
is already in effect for Pikes Peak...and have added snow advisories
for the higher elevations of the Wets...N Sangres...and for the C
mtns. The heaviest snow will fall over Pikes Peak.
Tonight...
Severe threat will continue over the far eastern plains, with the
greatest threat along and north of the boundary. Steady precip, with
embedded convection will develop/continue over the greater Pikes
Peak area as strong upslope flow in the lower atmosphere impinges
across this region. it is not out of the question that some areas in
the Pikes Peak area are going to see an inch of liquid...with local
amounts in excess of 2 inches possible. Heavy wet snow will fall
over the highest elevations of both Teller and El Paso counties. I
expect most of the accumulating snow will fall above ~9000 feet.
With the snow levels falling...the threat for flooding over the burn
scar will decrease.
Summarizing...
Severe storms will be possible over the Plains today. The severe
potential will extend includes the I-25 corridor region. I would not
be too surprised if the 1300 UTC SPC DY1 outlook has more of se CO
outlooked for severe weather based on the HRRR output. All severe
convective modes will be possible...with the greatest threat for a
tornado or two along the boundary that will extend across the
Plains. I anticipate a tornado watch will be issued later today for
parts of the plains.
Heavy rains will likely occur across most if not all of the Pikes
Peak region later this afternoon and into tonight. Some convective
heavy rains will likely occur later this afternoon. If one of these
storms develops over the burn scar...than a flash flood threat will
be possible. A flash flood watch may be needed later today for the
burn scar.
heavy snow will fall across the mtns. The heaviest accums will
occur above 9000 feet. The heaviest snow will fall over Pikes Peak.
/Hodanish
.LONG TERM...(Friday through Wednesday)
Issued at 347 AM MDT Thu May 26 2016
...Heavy rain and mountain snows continue Friday morning...
Main concern in the extended will be for Friday morning, as the
upper low tracks straight through southeastern Colorado. Storm looks
fairly dynamic, with h7-h5 flow in the 40-50 Kt range rounding the
low center in the NW quad. Mid level flow will be from the N to
NE...bringing a strong orographic component to the Ern mountain
ranges, and contributing to more widespread moderate to heavy precip
in the 12 through 18Z period Friday. The focus for the heaviest QPF
will be over the southern front range, Wets and Sangres, and the I-
25 corridor. The NAM has another 0.5 inches to inch of precip in
this region Fri morn. Other models not quite as wet, but still in
the 0.25-0.50 inch range. With mid level lapse rates falling rapidly
Fri morning, threat for intense convection will drop, but moderate
steady precip could lead to additional problems for local streams
and poor drainage areas. Snow levels will drop to around 8500-9000
feet Fri morning, then rebound to around 10K feet during the day.
Heavy snow accums likely for Pikes Peak above 11000 feet, and higher
elevations of the West and Sangres. Pikes Peak should see an
additional 4-6 inches Friday, and a couple inches for the other
mountain areas. Total snowfall for Pikes Peak could exceed one
foot. Steady precip will wind down Fri afternoon, but there
should still be widespread showers, particularly over the higher
terrain, through the evening. Temps Friday will be about 15
degrees below average for late May.
After Friday, rest of the forecast period is relatively uneventful,
with daily chances for showers, particularly over the mts, and
temps generally around or slightly below average. Quasi-zonal flow
on Sat will transition to SW flow aloft on Sunday as a weaker low
pressure system begins to move into western CO. This system will
move through late Monday into early Tue, and bring another round of
widespread showers and a few storms to the area. The parent low to
this trough will move through the northern Rockies and High Plains
during the midweek period. The GFS is a bit farther south and
stronger with this system than the ECMWF, and there is a large
ensemble spread by 144 hours and beyond. But it is likely the bulk
of this system will remain to our north. As the trough and
associated cold front passes to the east, the Plains will likely
see another round of showers and storms, some of which could be on
the strong side, in the Tue-Wed time period. Stayed pretty close to
the Blended ensemble-based grids for the latter part of the forecast
period, which progs near to slightly below average temps and low-
sct POPs for the region. Rose
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1133 AM MDT Thu May 26 2016
VFR conditions will transition to to MVFR as thunderstorms develop
over the mountains and spread eastward onto the plains this
afternoon through tonight. Strong to severe thunderstorms will be
possible this afternoon after 20-21z for KCOS and KPUB with
erratic wind gusts to 40 kts or higher along with hail...and heavy
rainfall. Winds will shift from the north after thunderstorms
roll through with gusts to 20-30 kts tonight. There may be a lull
in showers for the KCOS terminal before they increase again after
04z with more widespread MVFR CIGS and VIS due to rainfall. PUB
will see stratiform rain and MVFR conditions spread in after 09z.
Winds will increase again from the north at both KCOS and KPUB
Friday morning.
&&
.PUB Watches/Warnings/Advisories...
Winter Weather Advisory from 3 PM this afternoon to 6 AM MDT
Friday for COZ058-060.
Winter Storm Warning from 3 PM this afternoon to 6 PM MDT Friday
for COZ082.
Winter Weather Advisory from 3 PM this afternoon to noon MDT
Friday for COZ073-080.
&&
$$
UPDATE...KT
SHORT TERM...HODANISH
LONG TERM...ROSE
AVIATION...KT
Area Forecast Discussion
National Weather Service Pueblo CO
1131 AM MDT SAT MAY 28 2016
.SHORT TERM...(Today and tonight)
Issued at 353 AM MDT Sat May 28 2016
Currently...
Quiet early morning over the fcst area at this time (3:00 am). Skies
were predominantly clear across the entire region. temps were in the
40s across the Plains and 30s in the Valleys...20s mtns.
Today...
We could see a strong storm or two over the region today. Latest
runs of the HRRR are showing some stronger convection developing
over N El Paso county by early to mid afternoon. Marginal shear will
be in place and about 500-1000 J/KG of cape are fcst. Mid lvl flow
over the region will be modest...with 25 kt due zonal flow and 40
knt flow at jet level. A weak perturbation or two is noted in the
mid lvl flow. These parameters will be sufficient for a marginal
severe weather event if storms initiate.
Over the remainder of the Plains convection will be more isolated.
Over the mtns...scattered storms are likely especially over the
contdvd and Pikes Peak region.
Temps today will be seasonable...with U60/70s in El Paso county and
70s most of the rest of the Plains...60s valleys. Sfc winds will be
light and diurnally driven.
Tonight...
Convection over the mtns will roll onto the Plains and move east
during the evening. Extent of convection should be isolated...and
should move out of the State by late evening. Can`t rule out a
marginally svr storm given the modest forcing that will be over the
Plains this evening. /Hodanish
.LONG TERM...(Sunday through Friday)
Issued at 353 AM MDT Sat May 28 2016
Not much change to the forecast with active weather expected to
continue into the middle of the week. There are still some slight
model differences, but for the most part confidence is high in the
extended period.
Sunday and Monday...a weak upper level low is forecast to slowly
move out of Southern California into Arizona. This will spread
moist southwesterly flow aloft across Colorado with embedded
disturbances across the region. This will set the stage for shower
and thunderstorm development both days.
There will be the potential for severe thunderstorms Sunday
afternoon out near the Kansas border. It will all depend on where
the dryline sets up. Both the NAM and ECMWF have the dryline over
eastern Colorado, while the GFS progresses it east into western
Kansas by Sunday afternoon. For now will have a severe risk over
our far eastern counties Sunday afternoon where hail to an inch in
diameter and wind gust to 60 mph are possible. Elsewhere, expect
showers and thunderstorms to develop over the mountains by late
morning and spread east across the I-25 corridor during the
afternoon. Lightning, small hail and locally heavy rainfall will
all be possible.
There also appears to be a severe weather risk on Monday afternoon
as well. There is better model agreement with the dryline
developing over our far eastern counties. Strong to severe
thunderstorms will likely initiate in far eastern Colorado and
move into western Kansas by evening. Large hail and strong outflow
winds will be the primary threats near the Kansas border. Another
round of showers and thunderstorms are expected over the mountains
as well, which will spread east during the afternoon hours.
Temperatures Sunday and Monday will be warm with 70s to mid 80s
for the lower elevations.
Tuesday through Wednesday...southern Colorado is forecast to see
increased chances for widespread precipitation and cooler
temperatures. An upper storm system is forecast to strengthen over
the northern Rockies and move into the northern plains during this
period. This will send a cold front south across the region by
Tuesday morning with moist northeasterly upslope flow developing
across eastern Colorado. This low level moisture and upslope flow
will combine with upper level energy dropping south around the
upper low to produce widespread showers and thunderstorms across
the region, with the primary focus on the eastern mountains and
I-25 corridor. Locally moderate to heavy rain will be possible.
This pattern will continue into Wednesday with continued
widespread precipitation expected.
Temperatures will be cooler behind the frontal system. Still think
model guidance is a bit too warm with 60s and lower 70s. Given the
700 mb temperatures dropping to the 0-2C range, would not be
surprised to see highs in the 50s. This will also drive snow
levels down to near 8 kft. Modest accumulations will be possible
over the eastern mountain peaks, with minor accumulations possible
down to 8 kft.
Thursday and Friday...the upper system over the northern plains
will continue east while high pressure builds over the Great
Basin. This high pressure will build east into Colorado by late in
the week. Drier and warmer conditions are expected with afternoon
and evening mountain showers and thunderstorms, which may move off
the higher terrain into the adjacent plains. Highs will rise back
into the 80s. Mozley
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1131 AM MDT Sat May 28 2016
VFR CONDITIONS EXPECTED AT COS...PUB AND ALS WITH A MORE TYPICAL
LATE SPRING WEATHER PATTERN ACROSS THE AREA OVER THE NEXT 24 HOURS.
SCATTERED AFTERNOON AND EARLY EVENING SHOWERS AND THUNDERSTORMS
ARE EXPECTED OVER AND NEAR THE THE HIGHER TERRAIN...WITH A FEW
STORMS POSSIBLE ACROSS THE EASTERN PLAINS. BEST CHANCES OF STORMS
AFFECTING TERMINALS WILL BE AT COS AFT 20Z THRU 01Z. GUSTY OUTFLOW
WINDS AND LIGHTNING LOOK TO BE THE MAIN THREATS AT THE TERMAINALS.
&&
.PUB Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...HODANISH
LONG TERM...MOZLEY
AVIATION...MW