Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/30/19
Area Forecast Discussion
National Weather Service La Crosse WI
535 PM CST Fri Nov 29 2019
.SHORT TERM...(Tonight through Sunday)
Issued at 226 PM CST Fri Nov 29 2019
Sloppy. Chaotic. Disordered. Blotchy. All synonyms of messy, which
is a fair way to describe this forecast and the expected weather
over the next 24 to 48 hours. Even headlines are a challenge given
how complex the impact predictions are.
Large western upper trough will continue to push into the nation`s
mid-section next 24 hours. Very dynamic system with abundant
moisture to work with and problematic warm layer aloft. Already
seeing a mix of precipitation approaching from the southwest and
that trend will continue into tonight.
Stacked upper low progged to move across the region this weekend.
Models remain in fair agreement, although subtle details in
temperatures and ice aloft could make things shift. Strong warm air
advection starting this evening will keep temperatures from dropping
much at all and could even warm a bit. Mass ascent area will spread
precipitation in which could fall as snow initially, before mixing
as it works northward. Model soundings remain in critical zone near
freezing and then begin to warm aloft as layer advects northward.
Would not be surprised to see multiple preciptiation types as warm
layer aloft varies in that 1C to 4C spread. Even bumped up sleet
threat in case models are a bit too warm with this warm layer if
cooler, east flow ahead of the system holds things down a bit.
Advisories placed for areas mainly from Minnesota-Iowa stateline
northward where impact could be greater with just slightly cooler
temperatures.
On Saturday dry slot and loss of ice aloft will sweep into the area,
but how far north it gets is still in question. Some model
discrepancies on how this dry slot rotates in. Combined with warming
temperatures, bulk of area could switch over to all rain, but again -
very close on temperatures so any cooler air still in place could
lead to sleet or pockets of freezing rain. With colder air holding
further north, still appears that more snow will fall north of I-94,
or mix with sleet at times causing more impact, hence the warnings
and longer lived advisories.
Forecast becomes a bit more clear starting Saturday night, as cooler
air associated with upper low passage begins to eliminate risk for
melting or mixed precipitation. Transition over to all snow expected
going into Sunday, but interesting twist in last model runs suggest
could be some enhanced bands of snow develop directly in front of
east moving low. This could develop more enhanced preciptiation
closer to I-90 but confidence is not strong enough to include or
message at this point.
Some lingering snow will continue on Sunday as system exits. Minor
impacts expected and some light snow accumulations could work
southward.
.LONG TERM...(Monday through Friday)
Issued at 226 PM CST Fri Nov 29 2019
A welcomed break from active winter weather is in store for the work
week with seasonable temperatures for early December. Under upper
level northwest flow, short wave disturbances to bring a slight
chance for light snow in northern Wisconsin. For the rest of the
region, the next chance for precipitation returns the end of the
week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 535 AM CST Fri Nov 29 2019
Cigs: low stratus is going to hold fast across the region through
Sat, and likely through the better part of Sunday - mostly around or
below 1 kft.
WX/vsby: challenging pcpn type forecast with warm aloft/sfc and ice
in/out of cloud issues playing havoc with trying to refine what is
going to fall and when. Relying heavily on sfc obs and RAP bufkit
soundings, the most probable ptypes tonight should mostly run SNRA
with brief periods of sleet possible. Some threat for FZRA this
evening at KRST, but sfc temps are expected to slowly rise
overnight, mostly limiting these chances to this evening.
Soundings/temps then point to mostly just rain for ptype during the
day Sat...gradually mixing with and changing over to snow later that
night.
Anticipate vsby impacts with pcpn...generally 1-2sm when snow is in
involved, 3-5 with mostly rain. In addition, look like some BR will
be around, adding to pcpn related vsby restrictions.
Winds: tightening pressure gradient will increase the winds
overnight with sustained around 20 kts and +30 kt gusts at KRST by
mid morning. Direction should hold from the east.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory from 9 PM this evening to noon CST
Saturday for WIZ041>044-053-055.
Winter Weather Advisory from 9 PM this evening to noon CST
Sunday for WIZ029-032>034.
Winter Storm Warning from midnight tonight to noon CST Sunday
for WIZ017.
MN...Winter Weather Advisory from 6 PM this evening to 6 AM CST
Saturday for MNZ086>088-094>096.
Winter Weather Advisory from 9 PM this evening to noon CST
Sunday for MNZ079.
IA...Winter Weather Advisory from 6 PM this evening to 6 AM CST
Saturday for IAZ008.
&&
$$
SHORT TERM...Shea
LONG TERM...Peters
AVIATION...Lawrence
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
938 PM CST Fri Nov 29 2019
.UPDATE...
Same song, fourth verse, a little bit later and a little less fog.
With visibilities continuing to improve along and east of a
Fredericksburg to Boerne to San Antonio line we have dropped the
Dense Fog Advisory for these areas. It continues though for areas of
the Edwards Plateau and Rio Grande Plains as visibility remains
between 1/4 and 1/2 mile in most places. The warm front has moved
through Boerne and Kerrville and Fredericksburg, but has yet to make
it to Hondo. Only other change was to reduce the coverage of fog
after midnight to mainly areas west of I-35/the warm front.
&&
.PREV DISCUSSION... /ISSUED 826 PM CST Fri Nov 29 2019/
UPDATE...
Third update of the evening to expand the Dense Fog Advisory
westward. As was shown by the HRRR and expected as the warm front
moved westward the dense fog has expanded across the Edwards Plateau
and Rio Grande Plains with Rocksprings and Eagle Pass now reporting
1/4 mile visibility and Uvalde not far behind at 1/2 mile. We have
seen some improvement along the I-35 corridor in terms of visibility.
Will hold onto the Dense Fog Advisory there for another hour or so to
see if winds decrease. If they do then there may be some fog
development back across the I-35 corridor. If they don`t then the
Dense Fog Advisory will be dropped for these areas the warm front has
already moved through. Only other change was to adjust temperatures
based on the observations and the forecast position of the warm
front. This warmed overnight lows along and east of the I-35 corridor
slightly due to the westward progression of the front.
PREV DISCUSSION... /ISSUED 612 PM CST Fri Nov 29 2019/
UPDATE...
Another quick update for the newly issued Dense Fog Advisory. The
Advisory covers the Interstate 35 corridor and points westward across
parts of the Hill Country and areas west of the San Antonio metro.
Visibility in these areas has dropped to one quarter to one half mile
making driving hazardous. With today being a big post Thanksgiving
travel day and a Friday night we wanted to highlight the fog and
increase the messaging so that folks slowed down, increased their
driving distance and used their low beams while traveling overnight.
What is causing this is the very moist environment just to the north
of a warm front that is oriented parallel to the I-35 corridor. The
warm front has hung out along the Coastal Plains for the last 24
hours but is now slowly moving to the north and west. Austin
Bergstrom warmed 10 degrees and went from calm generally north winds
to SSE winds over 10 mph over the course of 25 minutes once the front
moved through. The HRRR continues to show the warm front hanging
around the I-35 corridor through the night waffling a bit westward
before building back east as the wind field weakens overnight. The
front itself is oriented parallel to the overall upper level flow
which is why we are not seeing a big push northward.
To the west of the warm front fog, drizzle, and light rain will
continue with the HRRR showing fog expanding towards the Rio Grande
and visibility dropping out west by 9pm. If this occurs an expansion
of the Dense Fog Advisory will be needed westward. In addition, if
the warm front continues to push west across the Austin Metro, some
of those counties may be able to be dropped from the Advisory.
PREV DISCUSSION... /ISSUED 559 PM CST Fri Nov 29 2019/
AVIATION /00Z TAFs/...
The main aviation concerns center around LIFR and VLIFR ceilings and
visibilities at the South Central Texas terminals this evening and
tonight.
For AUS... A warm front lifting across AUS will allow for conditions
to improve overnight and frequent amendments will likely be needed
based on short term trends as conditions fluctuate to MVFR or
possibly VFR at times. Warm air advection will allow for light rain
and drizzle to continue over night with a second round of showers
possible Saturday morning as a weak cold front slides across the
terminal. VFR conditions and northwest winds are expected by 20Z.
For SAT/SSF... Have started with a very pessimistic trend for SAT/SSF
as these terminals are expected to remain situated near a warm front
near Interstate 35 for the majority of the evening, resulting in
LIFR and VLIFR conditions persisting for most of the night. Near
surface warm air advection over this warm front will result in
periods of light rain or drizzle continuing through the night near
these terminals, allowing LIFR/VLIFR stratus to also persist. Mixing
within heavier showers may allow for a temporary improvement in
visibilities, however. Latest high resolution guidance indicates 1/4
mile visibilities may persist as late as 12Z Saturday before surface
winds begin to veer towards the southwest and if this trend
continues, updates to the TAF will be needed with the 06Z issuance.
Rapid improvement in ceilings and visibilities with a light west to
northwest wind shift are expected following the passage of a weak
cold front Saturday morning with VFR expected after 17Z.
For DRT... IFR conditions will deteriorate to LIFR as fog spreads
westward with southeast winds around 10 knots prevailing this
evening. VFR conditions return after frontal passage around 16Z.
PREV DISCUSSION... /ISSUED 449 PM CST Fri Nov 29 2019/
UPDATE...
With soupy weather continuing into the evening and overnight hours
the main purpose of this update is to add fog into the grids from now
through 06z. Observational trends do show patches of dense fog from
Burnet to Castroville to Georgetown, Pleasanton and San Antonio. Much
of the rest of the I-35 corridor is seeing visibility this evening
between 1/2 and 3 miles. The Coastal Plains, south of the warm front,
and the Rio Grande Plains are the only areas without visibility
restrictions. Fog, drizzle, and light rain will continue into the
overnight hours.
PREV DISCUSSION... /ISSUED 219 PM CST Fri Nov 29 2019/
SHORT TERM (Tonight through Saturday Night)...
Persistent overcast skies with fog and light rain continue this
afternoon over most of the area. The warm front is still slowly
moving further inland from the Coastal Plains. Though conditions are
expected to improve slightly, weak ascent across a very moist
boundary layer will leave most of the area damp with some drizzle and
patchy light rain along and around the I-35 corridor through this
evening. With warm air advection behind the warm front, paired with
overcast skies, overnight temperatures will increase slightly before
staying almost constant overnight. Fog redevelopment is expected
again tonight. Tomorrow will be quiet warm as we heat up before the
next cold front has a chance to clear everything out Saturday
afternoon. Skies should clear quickly behind the front with winds
shifting from the north. Saturday night lows will be back down to the
mid to upper 40s.
LONG TERM (Sunday through Friday)...
We maintain northerly winds and drier air for a couple of days as
high pressure ridging builds in. As that ridge shifts to the
northeast on Tuesday, winds switch back out of the southeast. This
kicks off a warming trend from Tuesday through mid to late week with
highs back up into the mid to upper 70s by Thursday. Another short
wave moves into the Central Plains Thursday and drags a weak Pacific
front across the area Thursday night into Friday morning.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 66 66 79 47 63 / 80 30 40 0 0
Austin Bergstrom Intl Airport 68 68 80 45 64 / 90 30 40 0 0
New Braunfels Muni Airport 72 66 81 46 65 / 90 20 30 0 0
Burnet Muni Airport 67 66 75 42 60 / 80 30 40 0 0
Del Rio Intl Airport 69 60 79 47 70 / 20 - 0 0 0
Georgetown Muni Airport 63 63 77 44 61 / 80 40 50 0 0
Hondo Muni Airport 66 65 84 46 70 / 80 20 - 0 0
San Marcos Muni Airport 72 69 81 45 64 / 90 20 30 0 0
La Grange - Fayette Regional 77 72 81 47 64 / 70 30 40 0 0
San Antonio Intl Airport 67 66 80 48 66 / 90 20 20 0 0
Stinson Muni Airport 67 67 82 50 66 / 90 20 20 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 6 AM CST Saturday for Bandera-Dimmit-
Edwards-Frio-Kerr-Kinney-Maverick-Medina-Real-Uvalde-Val Verde-
Zavala.
&&
$$
Aviation...Huffman
Short-Term/Long-Term...Treadway
Area Forecast Discussion
National Weather Service Hastings NE
553 PM CST Fri Nov 29 2019
.SHORT TERM...(This evening through Saturday)
Issued at 313 PM CST Fri Nov 29 2019
A very busy shift with -ZR lingering longer than expected...dense
fog...aviation concerns and wind issues.
Aloft: RAP tropopause analyses and WV imagery showed highly-
amplified SW flow over the Cntrl Plns...with a ridge over the Ern
USA and a deep trof in the W. A potent shrtwv trof was over AZ/NM
and lifting NE. This trof will induce lee cyclogenesis over CO
this eve...with the newly formed low moving to near ANW by 12Z/Sat
and then slowly E acrs Nrn NEB during the day.
Surface: Strong 1036 mb high pres was over Ern Canada. Dvlpg low
pres was over CO. This low will deepen to about 988 mb and move NE
into the Sandhills tonight...then E acrs Nrn NEB tomorrow.
Meanwhile...the occluded front will quickly sweep from SW-NE acrs
the CWA from 06Z-12Z tonight. Strong CAA will follow tomorrow.
For the rest of this afternoon: Cldy/foggy with sct shwrs. Isold
tstms will be psbl with elevated/MUCAPE up to 400 J/kg. Despite SE
winds...temps have been very stubborn to rise above 33F N of
I-80. ODX has measured 0.06" of ZR since 17Z. Therefore...the
Winter Wx Advisory has been extended until 01Z N and E of EAR...to
cover the spots that are still at 32F. Temps should finally climb
above 32 by early this eve.
Fog: Svrl airports have been reporting 1/4SM at various times
today...S and W of the Tri-Cities. This was initially handled with
an SPS...but conds are very favorable for widespread fog to
continue/redevelop and worsen tonight. Dwpts in the mid-upr 30s
are advecting over very cold ground (or snowpack). That combined
with warm rain (temps +8 within the inversion/warm nose) falling
into a cold sfc-based layer should result in already very low CIGs
(200-300 ft) lowering to the point that widespread dense fog will
occur tonight.
Issued a Dense Fog Advisory at 1954Z for the SW fringe of the CWA
to start...and then for the rest of the CWA beginning at 00Z.
Tonight: Foggy. Be careful if you have to travel. Vsbys will be
1/4 mi or less...but rapid improvement will occur from SW-NE with
the passage of the occluded front. Sct shwrs and psbly a few
isolated tstms...mainly before midnight.
Sat: Sunny to start from the Tri-Cities S and E...but wraparound
clds to the N and W will move SE and overtake the rest of the CWA.
A little bit of wraparound light snow or rain could move into
some areas...espcly after 18Z. There is some potential for a bit
of light accum well N of I-80 (less than 1").
Becoming very windy as the pres grad strengthens around the
occluding low. The High Wind Watch was upgraded and expanded to a
Warning at 1752Z for the entire CWA from 12 PM Sat-9 AM Sun. The
NAM/GFS/EC/RGEM all fcst a 50-55 kt wind max at 850 mb to cross
the entire CWA Sat afternoon thru Sat night. Confidence is high in
NW winds 35-45 mph at times...with gusts of 55-60 mph. Would not
be surprised to see a couple gusts near 65 mph.
Used a 50-50 blend of 06Z/12Z MAV winds...then incrsd another 4-5
kt Sat night as local studies of past high wind events indicate
that even MOS (which is usually the highest available guidance) is
6-8 kt too low. High wind events are extreme and the mdls (espcly
those based on climo) tend to underfcst the magnitude due to
their rarity.
.LONG TERM...(Saturday night through Friday)
Issued at 313 PM CST Fri Nov 29 2019
Aloft: The flow will remain split next week. The deep low over NE
NEB Sat eve will move E to the Srn GtLks Sun. Heights will rise
over the Cntrl Plns in NW flow. A shrtwv ridge will cross NEB/KS
Mon in advance of a wk Nrn stream shrtwv trof that will cross the
Nrn Plns Mon night. This trof will introduce low-amplitude WNW
flow over the Cntrl Plns for Tue-Wed. It conts to appear that a
Srn stream shrtwv trof will cross the Srn Plns Thu...possibly
affecting KS.
Surface: A wk trof will cross NEB/KS Mon. A Nrn stream cool front
is fcst to move thru Thu. There`s uncertainty on if a low will
form over the Srn Plns. The fcst is currently dry...but if this
happens...some light rain will be psbl S of I-80 down into N-cntrl
KS.
Temps: Sun will be the coldest day of the week. Temps will then
average slightly warmer than normal thru Fri.
Precip: A little -SN could linger N of I-80 Sat night into Sun
morning. Otherwise...the fcst is dry.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Saturday)
Issued at 549 PM CST Fri Nov 29 2019
Poor conditions with LIFR CIGS/VSBYS expected through the first
half of the TAF period. Some improvement is possible during the
morning hours Saturday...before MVFR CIGS return with the
developing low pressure system forecast to tract across the area.
At the same time expect winds to rapidly intensify around midday
as the pressure gradient increases with the deepening area of low
pressure...likely remaining gusty through the overnight hours
tomorrow night and into the first part of the day Sunday.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...High Wind Warning from noon Saturday to 9 AM CST Sunday for
NEZ039>041-046>049-060>064-072>077-082>087.
Dense Fog Advisory until 6 AM CST Saturday for NEZ039>041-
046>049-060>064-072>077-084>087.
Dense Fog Advisory until 3 AM CST Saturday for NEZ082-083.
Winter Weather Advisory until 7 PM CST this evening for
NEZ039>041-046>049-061>064.
KS...High Wind Warning from noon Saturday to 9 AM CST Sunday for
KSZ005>007-017>019.
Dense Fog Advisory until 6 AM CST Saturday for KSZ007-018-019.
Dense Fog Advisory until 3 AM CST Saturday for KSZ005-006-017.
&&
$$
SHORT TERM...Kelley
LONG TERM...Kelley
AVIATION...Rossi
Area Forecast Discussion
National Weather Service Paducah KY
905 PM CST Fri Nov 29 2019
.UPDATE...
Issued at 905 PM CST Fri Nov 29 2019
Updated the forecast to include the mention of fog tonight.
Received a report of dense fog in Carter and Ripley Counties
within the past hour, and similar conditions were observed just
west of our forecast area as well. Visibility forecast from such
models as the HRRR and GLAMP indicate the most dense fog should be
confined to our western four counties in southeast Missouri. As a
result, we have issued a Dense Fog Advisory for Carter, Ripley,
Butler, and Wayne counties until 3 AM. Visibilities should tend
to improve modestly shortly after midnight as the next batch of
rain moves in, though visibilities across much of southeast
Missouri, southern Illinois, and southwest Indiana may be reduced
to the 1 to 3 mile range for much of the overnight. The remainder
of the forecast is unchanged.
UPDATE Issued at 700 PM CST Fri Nov 29 2019
Made just a minor tweak to the forecast to confine the evening
thunder chance to our westernmost counties in southeast Missouri
and southwest Illinois. Better chances for thunder spread into the
area overnight with some increase in elevated instability. The
rest of the forecast is on track and unchanged from prior.
&&
.SHORT TERM...(Tonight through Sunday night)
Issued at 250 PM CST Fri Nov 29 2019
High pressure will continue to move east of the area. A large H5
low over the west U.S. will pinwheel, ejecting a strong compact
low at H5 and the surface ENE, ending up over Nebraska 12z
Saturday. We will see a warm front develop to our south, and move
into the area late tonight. The parent systems will move east
through Saturday night, ending up over the Great Lakes/Ohio
Valley region Sunday, finally reaching the Appalachians Sunday
night. A strong cold front will move to about I-55 by the end of
the day Saturday. It will rapidly move east through the evening,
and out of the area by midnight. The models were in fairly good
agreement overall, so we did not deviate much if any from our
guidance blend of data.
We expect warm advection, elevated convection tonight north of the
warm front, best chances north 1/2 of the area, slightly lower
toward the TN/AR borders, at least until late, when an increase is
anticipated with the warm front. Saturday, expect occasional
showers and thunderstorms to continue. The chance will continue
Saturday evening, and then clear out of the area. Locally heavy
rain is possible primarily north and east of a Carbondale IL to
Hopkinsville KY line. At most, just a chance of some minor issues.
A marginal risk area was added by SPC. Not really sure why.
Nothing has changed in the data over the past 3-4 days, and since
the time they originally advertised general thunder. Parameters
aren`t any better than a few days ago, when we had next to
nothing. But ya never know right? We cannot rule out some gusty
thunderstorm winds, mainly in the Saturday early evening time
frame.
Sunday, wrap around clouds will make for a cloudy day. It will be
rather breezy as well. By afternoon and into the nighttime hours,
there will be a chance of some rain showers, possibly snow showers
after dark, mainly across the EVV Tri-State area. Not looking at
impacts at this time.
.LONG TERM...(Monday through Friday)
Issued at 250 PM CST Fri Nov 29 2019
With the departure of the low pressure system towards the Mid-
Atlantic, cloud cover will decrease throughout the day Monday. The
cooler air accompanying the northwesterly breeze will result in near
40 for the high Monday and the upper 20s for a low Monday night.
Temperatures will rebound Tuesday with a surface wind shift towards
southwesterly flow through the day. A mid-level shortwave arrives
from the northwest Tuesday afternoon; however, precipitation
potential is limited with no measurable precipitation expected at
this time for the Quad State region. Mid-week, westerly flow and
high pressure at the surface will keep conditions dry with steady
temperatures near 50 for highs and in the lower 30s for lows.
Thursday night into Friday a low pressure system tracking along the
southern United States from the Four Corners region into the
southern Great Plains will arrive at the Mississippi Valley. Models
generally agree that the center of this system will pass to the
south of the Quad State though differ on the extent of that distance
which will be key for precipitation chances. For now, slight chance
to chance odds are forecast for this system.
&&
.AVIATION...
Issued at 549 PM CST Fri Nov 29 2019
Ceilings have been running higher than guidance would suggest, so
have erred on the optimistic side for much of tonight, but they
should in general lower through the period and most places will
reach IFR levels by morning.
The area of rain/showers currently over the region will push
eastward and likely out of the region by mid-evening. Another
area of showers and possibly thunderstorms will spread back across
KMVN and KEVV late this evening and into the overnight hours. The
tail end of this area will impact KCGI and KPAH in the pre-dawn
hours. This area will shift east of the TAF sites by midday.
Development later Saturday afternoon may stay southeast of the
KPAH and KOWB, leaving just scattered light showers over much of
the region through the afternoon.
A strong veering wind profile will develop late tonight through
Saturday. LLWS will be a concern when and where surface winds are
not gusting. South winds will increase by afternoon and try to
gust at times, but the low ceilings will hamper mixing.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...Dense Fog Advisory until 3 AM CST Saturday for MOZ100-107>109.
IN...None.
KY...None.
&&
$$
UPDATE...RJP
SHORT TERM...08
LONG TERM...ATL
AVIATION...DRS
Area Forecast Discussion
National Weather Service Pueblo CO
812 PM MST Fri Nov 29 2019
.UPDATE...
Issued at 811 PM MST Fri Nov 29 2019
Upadated for expiration of Winter Storm Warnings and Advisories
for the Sangre de Cristo Mountains.
UPDATE Issued at 513 PM MST Fri Nov 29 2019
Updated for expiration of High Wind Warning in the southern two-
thirds of the San Luis Valley, Huerfano, Las Animas, and Baca
Counties.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 243 PM MST Fri Nov 29 2019
...Potent storm bringing heavy wind driven snow to the
mountains...and damaging winds to portions of the southeast plains
through Saturday...
Upper low over the western U.S. was ejecting an impulse of energy
with an associated 150 kt upper jet across southern CO this
afternoon which has resulted in heavy wind driven orographically
enhanced snow across the southwest mountains. A line of rain/snow
showers along the leading edge of this impulse has progressed
eastward into the adjacent plains as of 22z. Brief poor visibility
and blowing snow accompanied this squall as it passed through the
San Luis Valley earlier this afternoon but warmer temperatures
across the plains should keep precipitation as rain. Some brief
embedded ice pellets or small hail will be possible with some of the
more intense embedded echoes across the plains as the line rolls
eastward but overall intensity should decrease as it moves away
from the mountains.
Meanwhile, high winds have impacted the San Luis Valley, Huerfano
and Las Animas counties this afternoon with gusts up to 75 mph
reported at the TAD ASOS. Expect these strong winds to continue for
another hour or two across the southern portions of the area before
decreasing again briefly this evening.
As the upper low lifts to the northeast and intensifies across
northeast CO/western NE, we start to loose a lot of forward wind
shear aloft and a mtn top inversion sets up. Cross-sections
continue to look favorable for a mountain wave high wind scenario
tonight into Saturday with high winds initially across the higher
peaks this evening, spreading into the adjacent lower elevations
after 10 pm. High res HRRR runs have advertised this well with each
successive run and have leaned heavily on it for headline issuances
this afternoon with most areas under high wind warnings starting
tonight and continuing through Saturday. Gusts up to 85 (perhaps 90
mph) will be possible across the higher peaks and east facing slopes
of the mountains, with gusts up to 65 to 75 mph along the adjacent I-
25 corridor, and gusts to 60 mph farther east. As the storm wraps
up to the northeast, strong winds will spread into portions of Kiowa
county and have added a high wind warning for this area for Saturday
afternoon into the evening hours. Mountain wave parameters break
down by mid afternoon with highest winds continuing across the
higher peaks and far northeast portions of the southeast CO plains
into early evening.
As far as winter highlights go, current suite of headlines still
looks on track with winter storm warnings going across the southwest
mountains through Saturday morning, and advisories persisting across
the central mountains through the morning. Although snow decreases
in the afternoon, high winds will continue across the Sawatch range
so will keep the high wind warning going through 6 PM up that way as
blowing snow will be the major concern anyway. The southwest
mountains will continue to see some orographically enhanced snow
showers with westerly flow favoring southern sections of the range
into the morning for a few more inches of snow through the morning
hours.
Overall, an active weather pattern over the next 24 hours. Travel
will be difficult due to snow in the mountains and strong cross
winds across the lower elevations. Power outages, and damage to
trees and structures will all be possible with the greatest threat
in and near the mountains, though depending on how quickly the storm
wraps up across northeast CO and NE, a high wind threat may extend
across portions of the far eastern plains tomorrow afternoon through
into the evening. -KT
.LONG TERM...(Saturday night through Friday)
Issued at 243 PM MST Fri Nov 29 2019
Fairly decent agreement with the operational solutions with slight
differences with a disturbance mid week. Ensemble spreads do
increase with time, but not bad, so confidence through the
extended period is a big higher.
Saturday night...the large upper level low over the Central Plains
will continue to eastward march with conditions quieting down by
morning. Winds will be gusty during the evening out near the
Kansas border, but should dissipate after midnight. A few light
snow showers are possible during the evening over the Central
Mountains, ending towards midnight. Dry conditions will then
prevail across the region into Sunday morning.
Sunday through Tuesday...high pressure is forecast to move across
the Rockies from Sunday into Tuesday. Generally dry conditions are
expected with the high pressure as it moves overhead. The GFS does
try and develop light snow showers over the Central Mountains
Monday night, but both the NAM and ECMWF are dry, and followed
those two models with dry conditions. Temperatures will warm
through the period, from the upper 40s on Sunday, into the mid to
upper 50s by Tuesday.
Wednesday into Thursday...a quick moving shortwave trough over the
western states is forecast to shift eastward across the region
beginning Wednesday, and exiting on Thursday. Snow will move into
the Continental Divide by Wednesday afternoon and prevail through
Thursday afternoon. A cold front will drop south across the Plains
Wednesday night with a northerly wind shift. As far as
precipitation for the lower elevations, much will depend on storm
track. The GFS is south across the Desert Southwest and keeps
precipitation confined to the mountains. The ECMWF is further
north, with precipitation spreading out across the Plains on
Thursday as the upper system moves east.
Friday...as the upper system departs to the east, high pressure
over the Great Basin will shift east into Colorado. Dry conditions
are expected for Friday. Mozley
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 243 PM MST Fri Nov 29 2019
Band of showers will continue to move eastward affecting the TAF
sites through 23-00z. Winds will be locally gusty up to 45 kts with
the showers. VFR conditions return with winds decreasing this
evening at all 3 terminals before increasing again towards midnight.
This will put a period of LLWS this evening through 14z for both
KCOS and KPUB with winds off the surface from the northwest at 60
kts. Winds will increase at both terminals around 15-16z with gusts
up to 55 to 60 kts from late morning into the afternoon. KALS will
see gusty winds through the night with winds becoming northwesterly
with gusts up to 45 kts on Saturday. Mountain snow showers and
obscurations will continue into tonight, though improvement is
expected across the Sangre De Cristo mountains this evening as drier
air spreads in. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
High Wind Warning until 3 PM MST Saturday for COZ077-078-083>088-
094.
High Wind Warning until 6 PM MST Saturday for COZ060-061-072-074-
076-079-081.
High Wind Warning from 11 AM to 7 PM MST Saturday for COZ096.
Winter Weather Advisory until 11 AM MST Saturday for COZ058-060-
061.
High Wind Warning until 6 PM MST Saturday for COZ073-075-080-082.
Winter Storm Warning until 11 AM MST Saturday for COZ066>068.
&&
$$
UPDATE...28
SHORT TERM...KT
LONG TERM...MOZLEY
AVIATION...KT