Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/29/21
Area Forecast Discussion
National Weather Service Des Moines IA
846 PM CST Tue Dec 28 2021
Issued at 825 PM CST Tue Dec 28 2021
Made some adjustments this evening to the snow forecast for
Wednesday as a low-amplitude mid level wave quickly slides
through the region.Model cross sections show weak static
stability and a zone of EPV reduction through the DGZ, co- located
with the zone of stronger frontogenetical lift stretched sw to ne
across the southern half of the state. This is a favorable setup
for an focused area of enhanced, deep lift to develop and produce
locally higher precipitation amounts. Snow ratios also may
contribute to boosted snowfall amounts with a cooler, more
dendritic profile and relatively relaxed winds supporting above
climo SLR. Cobb output suggests mean SLR of 16-19:1. Antecedent
dry air may play a significant limiting role as is shown in recent
HRRR runs, however confidence is growing that a band of locally
higher snowfall amounts may be realized tomorrow afternoon and
evening. Overall, snow totals were not substantially increased,
but were pushed toward the 1-3" range over a targeted area to
highlight the potential for locally higher snowfall amounts,
especially given the sensitive timing of any potential impacts
from heavier snowfall/rates around the afternoon commute.
.DISCUSSION.../Tonight through Tuesday/
Issued at 122 PM CST Tue Dec 28 2021
-Active and variable winter weather continues this week
-Light snow Wednesday
-Stronger system with cold temps and snow expected Saturday
Rest of today: Ongoing mixed precip event currently playing out
as exected and will continue lifting north and east this evening
as the short wave exits and cold front approaches from the west.
Tonight: Cold air will push in behind the cold front, stting the
stage for single digit lows tonight along Iowa`s northern border.
Wednesday: Southwest flow aloft continues and another short wave
will cross the state during the afternoon. Given the cold air in
place, this short wave is expected to generate a round of light
snow across much of the state. Moisture is limited and the short
wave will be moving quickly, so snow amounts are expected to be
minor with amounts under 2 inches.
Thursday: Temperatures should moderate a bit Thursday as
southerly low level flow returns in between systems. The next
cold front (a strong one this time) is progged to cross the area
Friday and Saturday: The cold air will push in Friday, setting the
stage for single digit lows Friday night and highs Saturday from
the single digits north to upper teens south. Then Saturday a
well advertised wave is progged to lift out of the southwest US
and take aim on the midwest. Models continue to differ considerably
on the evolution of the upper trough and subsequent track of the
surface low. Latest ECMWF runs continue to track the wave across
Iowa which would yield higher snowfall amounts for our area.
Meanwhile the GFS continues to track farther south, suggesting
lower snowfall amounts and impacts for our area. Of the two
models, the ECMWF has been a bit more consistent so would lean
slihtly toward that solution at this point. Regardless of the
eventual track, given the cold temperatures, any snow that does
occur is likely to be very fluffy and with wind gusts in the 15-25
mph range should blow around.
Sunday through Tuesday: After the long wave trough passes by
Saturday night, northwest flow will set up aloft and quieter
weather will kick off next week. After another colder day Sunday,
temperatures return to near normal for the start of the next work
.AVIATION.../For the 00Z TAFS through 00Z Wednesday evening/
Issued at 531 PM CST Tue Dec 28 2021
Low cigs/visby problems will persist into the evening hours for
the sites east of I-35, including KMCW, KALO, and KOTM. All sites
should improve to VFR by 09z and remain there for much of
Wednesday. Snow chances increase after 18z, but intensity and
location remains uncertain at this time. Included mention of -SN
and MVFR restrictions at KDSM after 20z to highlight the area of
highest confidence at this time, although this will need to be
refined in future TAF issuances.
Area Forecast Discussion
National Weather Service Goodland KS
413 PM MST Tue Dec 28 2021
.SHORT TERM...(This evening through Thursday)
Issued at 134 PM MST Tue Dec 28 2021
At the start of the short term period, current RAP analysis shows
the CWA having a west-southwesterly flow aloft being underneath the
base of an upper air trough on Tuesday afternoon hours. Model
guidance shows this trough tilting positively going into the Tuesday
night hours turning the flow over the CWA southwesterly. At the
surface, the cold front has passed through the CWA by the early
afternoon and is leaving some breezy mostly northerly winds looks to
be to have passed through the CWA with gusts up to around 35 mph in
some portions of the CWA for the rest of the afternoon. Winds look
to lighten by the evening hours going through the night. Cold lows
on Tuesday night between the upper single digits to the lower teens
are expected. Wind chills overnight look to drop between -3 and +3
degrees across the CWA particularly after midnight.
On Wednesday, models show the southwesterly flow over the continues
in the morning and transitions back to west-southwesterly by the
evening hours as the base of the trough moves over the CWA again.
Closer to the surface, cooler daytime high temperatures ranging
between the upper 20s and the middle 30s are expected in the CWA as
the latest NAM shows an 850mb cold air mass moving over the area
during the afternoon hours along with some cloud cover in the
morning that may inhibit early diurnal warming. While the NAM shows
a small chance for light precipitation in the northeastern quadrant
around 15Z, opted to keep low PoPs as other models do not show this.
Surface winds look to be around 5 to 10 mph that look mostly
northeasterly to northerly during the day that turn southerly
overnight. Overnight lows on Wednesday expect to range between the
upper single digits and the middle teens with wind chills ranging to
just below zero degrees to the upper single digits.
The flow over the CWA looks to stay mostly west-southwesterly again
throughout Thursday while models show a trough building out west and
reaching down to the southwestern CONUS. At the surface, there looks
to be a warmer air mass moving in from the southwest during the day
with a surface low near the CO/NE/KS border. Windy conditions return
to CWA particularly in the western half as southwesterly wind gusts
up to 35 mph are seen at this time. There may be some elevated to
near critical fire weather concerns in this area as well with
minimum RH values in the upper teens. Daytime high temperatures on
Thursday look to be in the lower to middle 50s with overnight lows
in the middle teens to middle 20s.
.LONG TERM...(Friday through Tuesday)
Issued at 113 PM MST Tue Dec 28 2021
A shot of cold arctic air set to impact the entire region Friday on
into Saturday. A strong cold front will push quickly south thru the
CWA during the day on Friday. Latest GFS/ECMWF do show this being
followed by a 500mb trough mainly Friday night into Saturday. This
trough will traverse the area by late Saturday, with mid level
ridging to follow to end off the holiday weekend.
Weather concerns with the passage of this system will range from
light snow area-wide, gusty winds bringing the potential for some
areas of blowing snow. And lastly, very cold wind chill readings as
temps drop sharply during the overnight periods.
First off at the onset, the quick moving cold front may trigger some
light precip in extreme south possibly starting as very light rain
but transition quickly as temps drop. The dry airmass this system
will work into going into Friday night and Saturday morning will
keep amounts low, with latest forecast trending around an inch.
Gusty winds could create areas of blowing snow and thus hazardous
travel conditions in spots. Will have to monitor for potential
Winter Weather Advisory issuance for potential travel impacts.
The latest 850mb temps show a range from -11c to -18c during the
overnight period Friday, with slightly warmer numbers Saturday night
in a -9c to -14c range.
For winds, strongest set to occur Friday into Saturday with gusts 25
to 30 mph possible. Sunday will have the potential for gusts nearing
25 mph on the return WSW flow as high pressure shifts east of the
area and a lee side trough setting up over the eastern slopes/Front
For the beginning of next week, a return to dry and more normal
conditions across the area.
For temps, highs on Friday will range widely due to the cold front
pushing south. Looking for a range from the 30s north of the
Interstate, to the 40s and lower 50s south. Currently this looks to
occur around the midday timeframe, but some uncertainty in frontal
passage timing in latest GFS/ECMWF. Highs on Saturday only in the
lower to mid 20s at best. An upward trend ensues on Sunday with a
return to a west-southwest downslope flow. Looking for a range in
the 40s, warmest west.
For overnight lows, Friday night will have a range from -1F to +6F.
Saturday night, just as cold with a range from -2F to +5F. By Sunday
night though, low to mid teens.
With the expected winds, wind chill readings will range from about -
14F to -19F Friday night, -9F to -18F for Saturday night and single
numbers above and below zero for Sunday night. If the trend holds
for the Fri/Sat timeframe, a Wind Chill Advisory may be needed.
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 410 PM MST Tue Dec 28 2021
VFR expected at both KGLD and KMCK through the TAF period. Surface
winds will be light behind a cold front, veering from northeast to
southeast at less than 10 kts.
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Morristown TN
1004 PM EST Tue Dec 28 2021
The forecast is generally on track this evening, so no major
changes are needed. Highest PoPs over the next few hours will be
in the Plateau in a low level convergence zone. Later tonight,
the HRR shows showers increasing as the LLJ strengthens and the
convergence zone moves into the TN Valley. The forecast PoPs of
likely to caregorical look warranted. Some obs have stayed very
warm due to gusty winds, and will make some adjustments to hourly
00Z TAF DISCUSSION.
The general trend to cigs through the night will be toward
lowering, particularly at CHA and TYS where MVFR conditions are
expected as rain showers develop in the area after 06Z. Downslope
winds should keep cigs VFR at TRI overnight and tomorrow morning.
Waves of showers will continue at times through tomorrow, with the
best chances in the afternoon. Any vis reductions should be
assoicated with showers, and mainly MVFR. TS may be possible at
CHA in the afternoon as well. Winds through the period will be
S-SW around 8-12 kt.
/ISSUED 324 PM EST Tue Dec 28 2021/
SHORT TERM...(Tonight and Wednesday)...
1) Conditional risk of strong to severe thunderstorms on Wednesday
afternoon; mainly across the southern Cumberland Plateau and
2) High moisture content will favor heavy rain rates and localized
flooding with thunderstorms.
We remain warm and anomalously moist on Wednesday as
deep SW flow continues across the region between longwave
troughing across the Great Plains and ridging off the Florida
coast. Isentropic ascent within this SW flow will continue to
bring cloud cover and scattered showers to the region. A strong
shortwave will move northeast through the upper flow across the
mid- Mississippi Valley and into the Great Lakes late on Wednesday
into Wednesday night. Some weak DPVA will be present across the
Tennessee Valley and Southern Appalachians, but the strongest
dynamics will remain to our west. A weak surface low is forecast
to develop across the Mississippi Valley and move ENE into KY and
the Ohio Valley on Wednesday night. A lingering boundary across
the region, in addition to the weak DPVA and thermodynamics, will
result in the potential for some severe weather on Wednesday
evening into Wednesday night across the Tennessee Valley.
The overall severe risk is conditional and will be dependent on
the amount of surface based instability. If height falls
associated with the shortwave are strong enough, and increase in
instability will be possible into the overnight hours. There is
still a lot of uncertainty on exactly where this better
instability and mid-level lapse rates set up, though, so the
overall risk is conditional. If enough instability is present, and
the RAP currently shows 500 to 800 J/Kg into Wednesday night,
shear is supportive for cellular storm modes such as multicell
clusters and supercells with a low potential for tornadoes and
strong winds; however, the more favorable setup continues to be to
our west where better low-level veering is present in closer
proximity to the developing surface low. Based on the current SPC
outlook and severe weather probabilities, will at least mention a
risk of some severe thunderstorms in the forecast for the southern
valley and southern Cumberland Plateau.
Thunderstorms that do develop will likely produce heavy rain rates
which may lead to some localized flooding issues. PW values are
around 1.4 inch across southern zones which is around the 99th
percentile to max of climatology. In addition, deep warm cloud
layer depths will result in warm rain processes. This combination
will favor heavy rain rates. The one mitigating factor will be
recent dry weather, but heavy rain rates could still result in
localized issues and prime the antecedent environment for more
flooding concerns over the remainder of the week.
LONG TERM...(Wednesday night through Tuesday)...
1. Unseasonably warm through Saturday.
2. Strong to severe storms possible late Wednesday and Wednesday
night. Heavy rainfall possible Wednesday night into Thursday morning.
3. Another strong system will impact the area bringing heavy
rainfall and the potential for strong storms Saturday and Saturday
4. Colder weather Sunday through Tuesday.
By Wednesday night, the weak shortwave will have lifted into the
Great Lakes. Curvature is weak with this shortwave with only weak
height falls spreading across the Tennessee and Ohio Valley. A
baroclinic zone will be entrenched from the central Appalachians
southwest across the Midsouth and into the southern plains. The weak
wave lifting across the Mississippi Valley will spark cyclogenesis,
albeit weak, along the boundary. This surface low will lift NE along
the front into the Ohio Valley by Thursday. The fetch of southerly
flow for several days now has been able to advect Gulf moisture
poleward into the Southeast and Tennessee Valley. Additional influx
of higher theta-e air will accompany a strengthening LLJ in response
to the wave to our northwest. Dewpoints will increase into the low
to mid 60`s by Wednesday night. This airmass characterized by low-
mid 60 dewpoints will yield weak MLCAPE values across at least
portions of the southern valley.
Ongoing convection at the start of the period due to primarily
isentropic ascent along the 290-300K surfaces will move NE across
much of the Tennessee Valley. Assuming some of this activity could
become surface based would present chances of strong to possibly
severe storms. The severe threat for Wednesday night is conditional
on instability. Recent point soundings from CAM guidance depicts
some low-level CAPE along with modest shear profiles. If we were to
see some breaks in the cloud cover then this could certainly modify
the boundary layer so that higher CAPEs could be realized. As the
low level jet continues to intensity, vertical wind shear will
increase. A potential wild card will be if a secondary surface low
can potentially develop as has been noted in several past runs from
the GFS. This would cause local backing of the wind profile and
subsequently lead to an increase in SRH. Another thing to watch for
is that recent guidance and forecast soundings show additional
warming near 700mb leading to a slight cap that may keep convective
coverage limited. This is especially true with the weak forcing
expected. Locally damaging winds will be the main threat with any
strong to severe storms although a secondary threat of an isolated
tornado or two is certainly possible with sufficient low-level CAPE
(3CAPE > 60J). Confidence is still rather low at this point on
convective mode and coverage, but the risk is there for strong to
The other hazard is locally heavy rainfall potential Wednesday night
and Thursday morning. Anomalous moisture will be present as PW
values surge to between 1.25-1.50 inches (200-300% above climo).
Additionally, these numbers are near the 99th percentile based on
1979-2009 CFSR climo. The anomalous moisture will likely interact
with a boundary that is progged to sag south into portions of the
area. NAM, GFS, and to a lesser extend the ECMWF depict an increase
in 850-700mb frontogenesis developing Wednesday night. This forcing
along with anomalous moisture will lead to periods of heavy
rainfall. Luckily, it has been relatively dry so that we should be
able to handle a couple inches of rainfall without major issues.
However, any training convection could cause localized flooding
On Thursday, the area remains well into the warm sector airmass.
Southwest flow aloft will continue to transport moisture into the
area. Forcing will be hard to come by on Thursday, but will leave in
PoPs for the higher terrain through Thursday night where upslope
could keep showers going across these areas. The warm weather
pattern continues for Friday and Saturday. On Friday, a warm front
lifts back north while aloft, a deep upper level northern stream
trough digs across the Rockies and phases with a southern stream
disturbance near the four-corners. Robust cyclogenesis develops
within increasing height fall across the plains. A couple of surface
lows will ride along the baroclinic zone Friday and again on
Saturday night. Numerous showers and thunderstorms will move through
the area beginning Friday and will continue through Saturday.
Moisture continues to be anomalous with this system. NAEFS tables
suggest Q and PW values will be well near the 99th percentile or
higher of climo. Additionally, PW values from ensembles are near 200-
300 percent of normal. Such anomalous moisture content along with
deep moisture profiles, high WBZ heights, and elevated CAPE supports
efficient warm rain processes. An additional couple inches of rain
is supported by deterministic and ensembles guidance. This
additional rainfall on top of recent rains from the midweek system
could cause flooding issues.
Finally, conditions will need to be monitored closely on Saturday
evening for possible rounds of strong to severe thunderstorms. Jet
dynamics increase ahead of the incoming trough axis with a 140-160
knot upper level jet. A LLJ develops in response across much of the
warm sector airmass. This will promote an increase in boundary layer
moisture/instability. There are a lot of unknowns in how much
instability can be achieved especially with possible convective
overturning issues given heavy rainfall. However, much stronger
winds fields means that vertical wind shear will be stronger with
High pressure descending from the plains will push the cold front
through the area on Sunday with impressive cold air advection behind
the front. Temperatures will return to near normal behind this
front. Depending on how much moisture is left behind the front, some
change over to light snow may be possible on the back side of this
system but it is still way to early to pinpoint any accumulations.
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 64 74 62 72 56 / 90 90 90 60 20
Knoxville McGhee Tyson Airport, TN 63 73 59 69 54 / 70 90 90 70 20
Oak Ridge, TN 63 71 59 69 53 / 80 90 90 50 20
Tri Cities Airport, TN 59 70 55 66 50 / 50 80 90 70 20
Area Forecast Discussion
National Weather Service Nashville TN
847 PM CST Tue Dec 28 2021
FOR EVENING DISCUSSION.
A line of showers and even a couple rumbles of thunder are focused
along our eastern extent of the CWA. Rain has been moderate to
heavy with 0.5"-1" falling in the last hour in southern Coffee
and western Grundy counties according to MRMS. 00z KOHX sounding
showed about 100-200 J/kg of MLCAPE which explains the lightning
being observed. RAP mesoanalysis currently shows higher
instability along and west of I-65 with a tongue of 500 J/kg of
MLCAPE. The front that keeps sagging and lifting the last couple
of days is currently along the Ohio River Valley and will sag back
down into the area after midnight bringing additional showers and
storms. Models keep 250-500 J/kg MLCAPE just south of the front
after midnight and into the early morning hours. Factoring in this
with ample shear, it is possible that we may see a strong storm
capable of gusty winds. As far as the current forecast is
concerned, the hourly PoPs had some minor adjustments, otherwise
no major changes were made.
00Z TAF DISCUSSION.
CKV/BNA/MQY/CSV...Several admendments possible thru 29/24Z per
expected fluctuations in ceiling heights, errosion/then
reestablishment of ceilings, fluctuations in vsbys, etc. 40kts
LLWS possible MQY 29/03Z-29/06Z per strengthening low level
atmospheric jet dynamics. Variable ceilings & vsbys expected thru
29/24Z. Mostly VFR/MFR with IFR at times. Light shwrs should
prevail or vcnty potential thru 29/24Z. Instability expected
to be strong enough to support tstm development around/after
29/12Z. Strongest convection expected generally S of terminals.
Swly sfc winds 5-15kts with gusts to around 20kts at times,
especially before 29/06Z when strength of sfc/low level pressure
gradient most enhanced. Due to sfc front proximity and possible
push SEWD into NW portions of mid state 26/09Z-26/24Z, sfc winds
could potentially veer SE CKV 26/09Z-26/24Z also.
Area Forecast Discussion
National Weather Service Phoenix AZ
500 PM MST Tue Dec 28 2021
Updated Aviation discussion.
Several fast moving weather systems will pass through the region
this week providing periodic chances for precipitation. The best
chances should occur through this evening and late Thursday
through Friday with lower desert rain showers and higher terrain
snowfall. The greatest weather impacts should occur late in the
week. The weather pattern may shift next week allowing the cooler,
unsettled conditions to be replaced by drier weather and
Scattered light showers continue this afternoon across south-
central Arizona ahead of an approaching shortwave trough
currently situated near southern California. Amounts from these
showers have been light (around a few hundredths of an inch) with
Phoenix Sky Harbor picking up 0.01" of rain so far. Temperatures
today will top out in the mid to upper 50s across central Arizona,
while areas across southeast California and southwest Arizona
that have seen clearing this afternoon finish in the low 60s.
The aforementioned shortwave trough will progress through the state
during the evening and promote additional shower development
mainly across central portions of the state. Amounts are expected
to remain light with most places across the Valley staying below
0.25". Areas that see more orographic enhancement will see better
totals with some of these areas potentially seeing amounts upwards
of 0.50-0.75". Snow levels will be around 4,500-5,000 feet with
wintry precipitation expected across the higher peaks east of
Phoenix into southern Gila County, such as the
Pinal/Superstition/Mazatzal Mountains, where a Winter Weather
Advisory is in effect for elevations above 4,500 feet through 5 AM
MST Wednesday morning. Several inches of snow will be possible
for these higher peaks, though a capping inversion above 700 mb
will inhibit dendritic growth and thus act to limit the snowfall
threat. The trough axis shifts east of the state going through the
overnight hours with showers tapering off across our forecast
area. HRRR suggest skies clearing out enough overnight for some
possible patchy fog development for areas that see rain. However,
additional modeled guidance keeps the region locked in under
thicker cloud cover and preclude any potential fog.
With the passage of the shortwave, the Desert Southwest will remain
under the influence of broad cyclonic flow through the next day or
so. Modeled soundings keep a saturated layer between 700-850 mb
during this time allowing for expansive cloud cover to persist
through much of this timeframe. With the lack of evident forcing
mechanisms, shower potential is expected to remain limited across
much of the CWA. NBM PoPs keep slight chances for rain Wednesday
before increasing Thursday ahead of our next weather system.
Confidence is now very good that a compact, yet deep negative PV
anomaly will intensify west of the Baja Thursday night, then eject
and become sheared and absorbed into the strengthen jet core
along the international border Friday. This system will partially
tap better quality subtropical moisture with a more meridional
sfc-H8 component allowing better poleward advection. However, the
intensity and rapid forward motion of an upstream wave blasting
south will cut the residency time of this PV anomaly and ability
to fully realize the potential IVT plume. In fact, the rapid
shearing of the wave will quickly yield veering winds and
significant restriction to the inland penetration of the moist
tongue. Nevertheless, boundary layer mixing ratios ~7 g/kg and
total column PWATs above 0.75" juxtaposed with favorable dynamics
should result in an excellent precipitation chance across much of
the forecast area. NBM POPs ranging from 50% west to 90% east seem
reasonable for this situation.
With the deep cold core northerly wave descending and amplifying
over the four corners, will need to watch for the potential of
moderate snow burst through Gila County Friday night. Residence time
of this wave and moisture corridor combined with the colder airmass
should be somewhat brief, and thus possibly restricting snow totals
though the stronger dynamics could overcome this temporal
deficiency. Regardless, this system will rapidly propagate into the
southern plains Saturday afternoon with a deep, cold continental
airmass bleeding south in its wake. Forecast thicknesses and H8
temperatures suggest freezing temperatures over non-urbanized,
sheltered lower elevations Sunday morning (i.e. colder than normal,
but nothing unusual for this time of year). The initial stage of
this pattern retrogression will be complete during the first part of
next week with a flat ridging/zonal flow becoming the more dominant
regime over the SW Conus. Typically this time of year, this pattern
will produce periodic thicker high clouds, but temperatures
moderating very close to the seasonal normal.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Anticipate scattered to numerous light showers primarily between
00-06Z with large fluctuations in ceilings as each shower passes
overhead. Within that period of time, anticipate ceilings and
visibilities to be lowest between 02Z-04Z with conditions at or
near MVFR thresholds. Prior to that, anticipate a lot of
variability in ceilings ranging from 4-7kft AGL with visibilities
AOA 6SM. After 06Z, shower probabilities decline quite a bit but
anticipate lingering ceilings of 3-4Kft AGL. Ceilings will
continue to linger through the day Wednesday though there may be a
period in the morning where ceilings temporarily scatter out.
Surface winds will favor westerly directions this evening before
trending to southeasterly overnight and favoring the southeast
quadrant during the day Wednesday.
Southeast California/Southwest Arizona including KIPL and KBLH:
Scattered clouds (occasionally broken) with bases 6-8Kft AGL will
continue through the evening and slowly decrease after
sunset. Southwest/Westerly windiness with gusts of 25-30kts will
decrease considerably this evening with lighter southwesterly
winds lingering overnight and through the morning. Above the
surface, moderate to strong westerly winds will continue but
conditions are expected to remain below LLWS conditions. Anticipate
some redevelopment of breezy conditions Wednesday afternoon but
not quite as strong as this afternoon.
Thursday through Monday:
Temperatures will continue below normal through this week, then
begin to moderate next week. A moist environment combined with
several weather disturbance will result in periodic chances for
precipitation with some snowfall accumulation over higher terrain in
eastern districts Friday. Minimum afternoon humidity levels will
struggle to reach 40% with some drying arriving over the weekend.
Overnight recovery should be excellent in a 60-100% range. Wind
speeds appear fairly typical for the season with potentially some
enhancement of northerly winds behind a front over the weekend.
AZ...Winter Weather Advisory until 5 AM MST Wednesday for AZZ557-558-