Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/06/21
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
834 PM MST Tue Jan 5 2021
Last several runs of the HRRR and RAP13 indicate potential for a
period of strong north winds later tonight over far northeast NM,
then again late Wednesday morning before tapering off. Also, while
still relatively small, localized higher QPF/pops are indicated as
well, although resulting snowfall will likely be around an inch or so
if the models are close. Cloud cover looks to be more extensive over
eastern NM as well. Went ahead with a wind advisory, and along with
the ZFP, those products are already out.
.PREV DISCUSSION...501 PM MST Tue Jan 5 2021...
00Z TAF CYCLE
Gusty west to northwest winds to around 35 or 40kt along the central
mt chain and portions of ern NM to diminish aft 06/02Z while
becoming more nly. Sfc low over far se CO at 23Z to slide to the se,
with cold frontal boundary pushing into ne NM on gusty nly wind to
around 40kt. Lcl MVFR cigs/vsbys obscuring terrain in -shsn over far
ne NM to develop around 06/02Z impacting KRTN to KCAO through 06/12Z,
while nly wind shift reaches KCVS by around 05Z. Improving conditions
over ern NM aft 06/15Z.
.PREV DISCUSSION...340 PM MST Tue Jan 5 2021...
Expect strong winds to gradually weaken this evening, although
northerly gusty conditions will persist tonight along the Oklahoma
and Texas borders as a backdoor front slides southward through the
region. Quiet weather conditions are expected for Wednesday through
Friday. The next storm system is forecast to impact portions of New
Mexico on Saturday through Sunday morning. It appears this feature
will bring precipitation in the form of light to moderate snow over
the northern mountains as well as the eastern plains of New Mexico.
Activity may mix with rain over the southeast. Colder temperatures
and gusty winds will also accompany this storm system. It`s still a
little too early to know the exact impacts from this storm, however
those with travel plans this weekend are encouraged to stay abreast
to the latest forecasts.
SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)...
Winds are expected to diminish in the wake of the Pacific front
that passed through earlier today, and as such will allow the Wind
Advisory to expire on schedule at 01Z. Even drier air will be
advected into the Land of Enchantment behind the front with clearing
skies. Winds will decouple by the evening, allowing strong valley
inversions to setup tonight across western and northern NM. Cooler
overnight temperatures are expected for most locales, though these
readings will still be near to above normal. A backdoor front will
progress south across the eastern plains, bringing breezy northerly
winds to areas along the OK/TX border.
Temperatures on Wednesday will be cooler areawide, with highs across
the eastern plains reaching 10 to 15F below today`s readings. Breezy
conditions will persist along the TX border behind the backdoor
front into the afternoon, due to amplified flow aloft. Elsewhere, a
quiet day is in store with dry conditions and sunny skies. 12
LONG TERM...(THURSDAY THROUGH TUESDAY)...
A low-amplitude ridge axis will gradually roll east of the Land of
Enchantment for Thursday with high temperatures near/slightly above
average. Meanwhile, a relatively weak shortwave trough originating
from the PacNW will progress its way across the central Rockies for
Thursday/Thursday night. It will bring nothing more than some high
clouds across the region, but expect a backdoor front to offer weak
cold air advection in its wake Thursday night and Friday. This will
push high temperatures a tad below normal in the ern plains for the
last day of the work week.
Expect a rinse and repeat weather pattern with a relatively low-
amplitude ridge traversing the state on Friday. Yet another, albeit
stronger piece of energy will dive southeast toward the central and
southern Rockies. This feature will bring greater hopes for precip
chances early Saturday through Sunday morning as it tracks through
northern and central NM. Surprisingly, there is good agreement on
the placement, strength and timing of this feature between the GFS
and ECWMF deterministic and ensemble members. A weak low could form,
but will likely be short-lived in the fast-moving flow aloft. There
is one outlier, the deterministic Canadian which has a well-defined
closed low and places it on a trajectory from northern AZ through
southern NM, which is a bit further west than the GFS/ECMWF. Will
not entertain at this time, but if this solution materializes, then
winter weather impacts could be felt further west over western and
central NM. Regardless, another front will sweep through the region
with upslope flow being in phase with the upper level dynamics, and
this will bring a decent shot for precipitation over the ern plains.
Unfortunately, the speed of this system may be a limiting factor for
significant/major snowfall totals.
The barrage of upper level systems continues with a third feature
embedded within north-northwest flow, albeit weaker and drier, will
swing through the state on Monday. DPorter
Winds will be diminishing into the eve hours, with the exception
of near and along the OK/TX borders, as a backdoor front descends
across the eastern plains Tuesday night. Poor ventilation can be
expected on Wednesday, with the exception of the far eastern plains
where mixing heights will be higher alongside stronger transport
winds. Breezy northerly winds will persist across the far eastern
plains throughout the day on Wednesday, leading to brief elevated
fire weather conditions near the OK/TX borders.
Dry conditions are expected to prevail on Thursday, with
temperatures rebounding. Widespread poor ventilation rates can be
expected Thursday and Friday. The next chance for wetting precip
arrives Saturday as an upper level system and associated cold front
moves through the state. The greatest potential for accumulating
snowfall will be favored over the northern mountains and the eastern
Wind Advisory until noon MST Wednesday for the following zones...
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
918 PM CST Tue Jan 5 2021
Issued at 918 PM CST Tue Jan 5 2021
Upper level low pressure area pivoting in northeast sd late this
evening with really good returns on radar. Webcams and surface obs
showing snow along with rain with these returns. The issue for
tonight will be the extent of the radar returns and intensity
along with the time of changeover to all snow. Expect the
changeover to occur as the temperatures cool down with the
precipitation by around midnight or shortly after. The initial
rainfall and warmer temperatures will affect the snowfall amounts.
Have lowered snowfall amounts a little already. Some freezing
rain is still also possible west of the James Valley tonight. Made
several changes to the forecast.
UPDATE Issued at 545 PM CST Tue Jan 5 2021
00z aviation discussion updated below.
.SHORT TERM...(This Evening through Wednesday Night)
Issued at 251 PM CST Tue Jan 5 2021
An approaching sfc trough and mid level low will bring some snow to
the region tonight. At the moment the latest guidance keeps the
heaviest snow potential in and around the James Valley in the axis
of the trough. Tossed the RAP out for this forecast area given its
penchant for too much fzra even with moisture in the snow growth
region and profiles all below freezing by late evening. Southerly
flow ahead of the low has primed the region with increasing mid
level moisture. Prior to full saturation at the lower levels there
could be some freezing drizzle that mixes in, especially along
the I- 90 corridor. Areas with higher omega and better forcing
with saturated profiles into the snow growth region seem to be
focused from Brown to Marshall/Day counties. Added a winter
weather advisory where 2 to 4 inches is likely though confidence
is not high on the exact placement of highest snow as it will be
in a narrow band. As the snow exits from north to south on
Wednesday, there could be some periods of freezing drizzle mixed
in. Generally leaned toward 75th percentile snow accumulations
with higher than NBM SLRs since winds will not be that strong and
temps will fall below 30F tonight. Couldn`t justify a 7:1 ratio in
those conditions as the NBM had.
.LONG TERM...(Thursday through Tuesday)
Issued at 251 PM CST Tue Jan 5 2021
Dry conditions start the long term, however increasing confidence of
a secondary wave moving into the region Friday, bringing light
accumulation chances. Upper flow looks to remain weak during the out
period which will limit moisture potential. Messy upper flow will
also bring multiple waves throughout the out period, however low
confidence of any precipitation with these disturbances aside from
the light accumulation potential on Friday.
While temperatures do cool down slightly moving into the weekend,
overall pattern should keep highs slightly above normal through the
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 545 PM CST Tue Jan 5 2021
A slow moving upper level low pressure area over South Dakota will
bring mainly snow to ABR and ATY tonight into Wednesday. There could
also be some light rain or freezing rain at times. IFR/MVFR ceilings
and vsbys are expected at ABR and ATY through Wednesday afternoon.
Otherwise, VFR conditions at PIR and MBG will become MVFR tonight
and remain through Wednesday as low clouds move in.
SD...Winter Weather Advisory until noon CST Wednesday for SDZ005>007-
Area Forecast Discussion
National Weather Service Bismarck ND
941 PM CST Tue Jan 5 2021
Issued at 936 PM CST Tue Jan 5 2021
Increased the rain, freezing rain, snow chances across the James
River Valley. Models performed badly with this event, with much
more rain and freezing rain at the onset of this event than what
was depicted. We are finally changing over to snow, but not before
a tenth of an inch or more of rain/freezing rain fell across
Dickey, LaMoure, southern Stutsman, and eastern Logan and
McIntosh counties. It goes without saying travel is hazardous for
these locations. At this point, will stick with the special
weather statement and elevate the expected impacts.
UPDATE Issued at 713 PM CST Tue Jan 5 2021
The forecast for tonight remains on track. Increased POPs across
my southeast based on latest radar loop and short term guidance.
Will keep a wintry mix through the first few hours of this event
before all precipitation changes over to snow. Will also maintain
the SPS as is.
.SHORT TERM...(This evening through Wednesday)
Issued at 333 PM CST Tue Jan 5 2021
The short term forecast is highlighted by accumulating snow in the
James River Valley tonight into Wednesday morning.
This afternoon, a shortwave upper trough was located over the
Northern Rockies, with two surface low pressures in the
surrounding area that will influence our forecast area through the
short term. One is located in central Saskatchewan, with a
trailing frontal boundary that is just getting to the western edge
of the forecast area as of 20 UTC. Weak radar returns have been
persisting all day along and ahead of this front, with some light
rain reported in the northwest and some light snow grains observed
in north Bismarck, but otherwise a significant dry layer in the
low and mid levels has kept most precipitation from reaching the
surface. A chance of rain and snow will follow the front as it
pushes east through the afternoon and evening, but overall minimal
precipitation is expected with this feature.
The second surface low is located in southwest South Dakota, and
is expected to move northeast through South Dakota this evening
and overnight. This is where our focus is in terms of accumulating
snow, with precipitation wrapping around the north side of the
low in line with an upper vort max. Current forecast has the
highest amounts of 2-4 inches in Dickey and LaMoure Counties, with
1-2 inches in Stutsman, Logan, and McIntosh, and less than an
inch elsewhere. Some of the 24-hour postage stamps from the 12 UTC
HREF highlight the potential for higher snowfall amounts, on the
order of 4-6 inches of accumulation. Not too strong of a signal in
high-res guidance for this kind of heavy banded snow, with a
modest band of frontogenetical forcing in the latest RAP run and
moderately strong omega overnight (depending on what guidance you
choose), but we`re not quite confident enough to have that high of
snow amounts in the forecast, although it is possible. Dry air
has been the main concern with this system, with guidance not
showing saturation in the lower levels until after 3 UTC. Any
delay in this could lessen snow accumulations a bit. Wasn`t quite
enough snow to go for an advisory, but will put out an SPS to
message the snow potential.
There also is the potential for some light freezing rain in the
James River Valley this evening with a small warm nose aloft, but
with BUFKIT soundings only showing this potential for an hour or
two, and still concerns with dry air, decided to keep any ice
accumulations very minimal to none, but will message the
Snow will taper off Wednesday morning in the James River Valley,
with some patchy fog from the north-central through the James
River Valley. Skies will clear in the west and parts of the
central, but the James River Valley will likely stay overcast
through the day. Highs will generally be in the 30s, with lower
40s possible in the southwest.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 333 PM CST Tue Jan 5 2021
The extended forecast is highlighted by continued above average
temperatures, with a chance for snow Thursday night into Friday.
Quiet weather won`t last long as the chance for snow returns
Thursday night with another shortwave approaching the region.
Overall, the forcing with this system looks only marginal, so
current thought is it will be more of a longer duration but light
snow event. Still quite a large spread in ensemble guidance for
this chance of snow, but a general spatial pattern is emerging
when looking at individual ensemble members, with light
accumulations extending through most of western and central North
Dakota, and a swath of slightly higher totals embedded from the
southwest to the north central. Both GEFS and WPC Super Ensemble
plumes have some slight clustering from 0-0.10" of QPF, especially
at Bismarck and Jamestown. However, both of these as well as
Williston, Dickinson, and Minot all still have a wide range of
solutions up to 0.40" of QPF, so there is certainly potential for
a few inches of snow accumulation.
As we head into the weekend, some light snow might linger into
Saturday, but not seeing much in terms of precipitation looking
into the start of next work week. Temperatures should continue to
stay above average, with highs generally in the mid 20s to upper
30s, before CIPs analogs are favoring a transition to colder
temperatures across the Northern Plains in the 12-14 day range.
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 713 PM CST Tue Jan 5 2021
Mainly VFR conditions expected through the TAF period except for
at KJMS. Chance of light precipitation across central ND this
evening mainly in the form of light snow. Across the James River
Valley, accumulating snow is expected tonight, along with an hour
or two of mixed precipitation. Reduced visibilities from fog and
IFR ceilings also expected at KJMS after 03Z and continuing
through the end of the TAF period. MVFR ceilings are possible
along the cold front that will push through, beginning in the
northwest after 00Z.