NWS Hastings, NE wrote its last area forecast discussion before the first event at Jan 11, 11:22 AM CST, 4 hours 38 minutes earlier. Its key messages:
Area forecast discussion, Jan 11, 11:22 AM CST, 4 hours 38 minutes before
Area Forecast Discussion
National Weather Service Hastings NE
1122 AM CST Thu Jan 11 2024
.KEY MESSAGES...
- Our next winter storm brings accumulating snow and blowing
snow to our entire coverage area (CWA) between later this
afternoon through Friday morning, but it is increasingly-
apparent that eastern areas will be harder hit than western
areas (Winter Storm Warning several eastern counties...Winter
Weather Advisory remains elsewhere).
- Extremely high confidence in the arrival of our first "Arctic
blast" of the season especially late tonight through next
Tuesday morning, with truly dangerously cold temperatures and
especially wind chills triggering Advisories/Warnings. The
overall-worst cold is centered on this weekend.
- While bitterly cold wind chills/temps are clearly the NUMBER
ONE concern for Friday night onward, there are some
additional, currently-low confidence chances for snow between
Friday night-Sunday night. At this time, there is too much
"model chaos" to pin down any potentially more organized
chances with any degree of confidence, but at least for now,
none appear significant.
- Although not truly warm by ANY means, a gradual recovery out
of the deep freeze is expected for Tues-Wed that at least
gets us out of "Advisory/Warning- worthy" territory, with high
temps expected to rebound into mainly the teens Tues/mainly
20s Wed.
&&
.DISCUSSION...
Issued at 526 AM CST Thu Jan 11 2024
- GENERAL FORECAST COMMENTS (mainly on the winter storm):
It's been another busy shift trying to pin down the
trends/details of our next winter storm/snow event later this
afternoon into Friday, along with the ultimate magnitude of just
HOW cold it will get over these next several days (for sure
cold enough to potentially threaten several daily records at
Grand Island/Hastings...see separate Climate section below for
rundown of current records most favored to be threatened).
Getting back to the short-term winter storm, unfortunately
models over the last 12-36 hours have exhibited just enough
variability from run-to-run that our forecast snow totals have
"flip- flopped" up/down at least modestly (up to a few inches),
which has made for some frustration regarding choosing the
appropriate "headline" (Warning vs. Advisory). Am still not
totally comfortable with our actual snow amount forecast, but
it is increasingly-clear that the eastern half of our CWA
(especially east of Hwy 281) will see more snow than our west
(lowest amounts pretty clearly near/west of Highway 183). We are
not talking "super heavy" snow amounts here ("only" 5-6" in
eastern areas), but the combo of the drier/more powdery snow
(especially compared to the earlier week system) will likely be
blown about pretty efficiently by northerly winds gusting up to
around 35 MPH, accentuating storm impacts somewhat and likely
leading to at least localized near-blizzard conditions. That
being said, official Blizzard Warnings were not seriously
considered at this time, given that forecast wind speeds are
only hitting the marginal end of official Blizzard criteria.
that being said, felt the snow+wind combo was worthy of
upgrading our eastern-most two columns of Nebraska counties
(along/east of Hwy 14) from Winter Weather Advisory to Winter
Storm Warning.
Before diving into more chronological forecast details, also
want to emphasize that although we decided to "keep it simple"
by keeping the "start time" of the Advisory/Warning the same for
the entire CWA (3 PM), that in reality MOST of the CWA
(especially east) probably won't see snow really get going until
6-8 PM. Just a gentle reminder that winter Warning/Advisory
start times/end times are rarely exact...just ballpark (don't
take them too literally).
- CURRENT/RECENT WEATHER SCENE AS OF 430 AM:
As expected, it's been a precipitation-free night, but the very
leading edges of our LONG-DISCUSSED Arctic cold front is slowly
progressing from north-to-south across our CWA, it's passage
marked by a switch to still fairly light-but-steady north-
northeast winds, along with spotty patches of low clouds. The
presence of this boundary can really be seen when looking
slightly beyond our CWA borders, with temps ranging from single
digits in northern NE, to some 20s still in central KS. Within
our CWA, lows this morning are on track to bottom out anywhere
from 5-10 north-northeast to teens near/south of the KS border.
In the big picture of the mid-upper levels, water vapor
satellite and short term model data clearly depict our next
approaching (currently positively-tilted) shortwave trough
heading generally eastward along an axis from WY to AZ/NM, with
the very leading/eastward edges of light snow just approaching
the NE/WY border.
- TODAY-FRIDAY NIGHT (winter storm and Arctic air arrives):
- The snow:
Over the course of these next 24 hours, the large- scale upper
trough will start to take a more neutral tilt as a vorticity max
in its base intensifies as it reaches the OK/TX border by
sunrise Friday, but with its northward axis extending up into
our area. Fortunately, confidence is at least somewhat-high
regarding the onset of snow, wind speeds etc. For this morning,
have actually removed small snow chances (PoPs) from western
zones as we should get through Noon snow-free. Then especially
the western 1/2 to 1/3 of our CWA will see the initial onset of
snow this afternoon as sufficient low-mid level saturation/lift
arrives. However, for MOST of our CWA (especially east of Hwy
281), it will likely be more-so 6-8 PM until snow REALLY gets
going. Once it does, look for a decent area of moderate to
perhaps embedded heavier snow to really take off as the larger-
scale system itself gets more organized. For sure, this will be
a drier/more powdery snow compared to most of what fell earlier
in the week (owing to colder temps), and it will likely blow
around fairly efficiently as sustained north winds of 15-25
MPH/gusts to around 35 MPH prevail. The vast majority of snow
within our CWA will fall this evening-overnight, then gradually
ending from west-to-east on Friday morning as the upper system
continues to intensify/become more negatively tilted as it turns
northeast toward the Great Lakes (we are only catching the
western reaches/"glancing blow" of this system that will pack
more of a snow/wind punch across states to our east-northeast).
As for official forecast snow amounts, we are looking for only
1-2" in our far western counties (west of Hwy 183), generally
2-4" from Hwy 183 eastward to around Hwy 281 (including Tri
Cities), and potential for more so 5-6" counties east of Highway
281) as supported by various models including ECMWF ensemble
data...note a slight increase from previous forecast. Although
our "official" Warning criteria is 6" in our Neb zones, we opted
to be slightly "lenient" given the potential for blowing
snow/reduced visibility and upgrade those counties in our east
most favored to pick up 5-6". Meanwhile, left the Winter Weather
Advisory going for all other counties (albeit a bit "weak" far
west). Like our last storm, truly accurate/official snow amounts
will again be challenging to measure, especially given pre-
existing snow cover. Left the end time of the Advisory/Warning
as Noon Friday, although some lingering blowing snow and maybe
even flurries are possible (gusts gradually easing under 30 MPH
though, but still breezy into Friday night). Late Friday night,
some residual light snow/flurries could affect our area as a
weaker/reinforcing wave drops in behind the departed primary
one, but this is not currently expected to amount to much.
- Temps/wind chills:
Hopefully you enjoyed yesterday's 30s/40s because they are LONG
gone for probably at least 10-14 days! Actual high temps today
(which might prove to be too warm as Arctic airmasses often move
in slightly faster than expected) are only teens north/20s
south. Low temps tonight mainly single digits above zero. Highs
Friday mainly only 5-10 most areas, then lows Friday night
single digits below zero. More importantly, dangerously cold
wind chills of mainly -15 to -20 (spotty -25 north) will become
widespread tonight into Friday AM, and this is covered by a CWA-
wide Wind Chill Advisory. Starting Friday night into Sat AM (and
several nights/morning thereafter), even more dangerous wind
chills of -25 to -40 (spotty -45 cannot be ruled out) will be
common. As a result, it was decided to just "keep it simple" and
convert the long-fuse Wind Chill Watch issued 24 hours ago for
Fri night through Mon night/Tues AM to a long-fuse Wind Chill
Warning (even though not every location will necessarily meet
Warning criteria of -30 each night/morning).
-SATURDAY-SUNDAY (brutally cold weekend):
In short, this time frame will simply be brutally cold, above
all else. Highs BOTh days are likely to fail to reach ZERO in
most areas, with overnight lows teens BELOW zero, with even
lighter north winds promoting dangerously cold wind chills of at
least -25 to -40. Snow-wise, various, low-confidence chances
exist, and although nothing looks "major" at this time, we will
need to monitor for bands that could easily drop another inch or
two in the frigid airmass.
- MONDAY-WEDNESDAY (gradual recovery:
Although especially Monday daytime could still feature some
pesky snow chances, the forecast for Tues-Wed is currently
snow- free and the main story will be the end of the truly
BRUTAL cold, and transition toward more "regular" January cold.
High temps Mon look to recover to single digits above zero, then
mainly teen Tuesday and 20s (maybe even a few 30s?) for
Wednesday, but there are some bigger model differences by then.
&&
.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1117 AM CST Thu Jan 11 2024
The midday hour brings VFR conditions to much of the immediate
area, but deteriorating conditions are expected, especially late
this afternoon into this evening and tonight. An upper level
storm system will bring snow chances to both terminal sites,
with sub-1SM visibilities and sub-1000ft ceilings expected as
the main band of snow sets up. This band gradually shifts east
with time, with slight improvements (but still IFR/LIFR
conditions not out of the question) possible through the early
morning hours Friday...then more improvement after sunrise.
Gusty northerly winds expected throughout this period, with BLSN
being a concern this evening through the end of this period.
&&
.CLIMATE...
Issued at 617 AM CST Thu Jan 11 2024
Several daily temperature records appear potentially threatened
during our upcoming "Arctic blast" Friday-Monday at Grand
Island/Hastings airports (our two primary long-term stations for
which we issue formal Record Event Reports/RERs). A few of the
records that appear MOST favored to be at least "near-threatened
or possibly outright-broken Jan. 12-15 follow:
-- Grand Island (GRI):
Record cold lows:
Jan. 14 (Sunday): current record -13 (1972)
Jan. 15 (Monday): current record -14 (2005)
Record cold highs/Max T:
Jan. 13 (Saturday): current record 4 (1979/1912)
Jan. 14 (Sunday): current record 1 (2005/1979)
Jan. 15: (Monday); current record 4 (2005)
-- Hastings (HSI):
Record cold lows:
Jan. 15 (Monday): current record -11 (1972)
Record cold highs/Max T:
Jan. 12 (Friday): current record 6 (2011/1974/1963)
Jan. 13 (Saturday): current record -1 (1916)
Jan. 14 (Sunday): current record 3 (2005)
Jan. 15: (Monday); current record 6 (2005)
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...Winter Weather Advisory from 3 PM this afternoon to noon CST
Friday for NEZ039-040-046-047-060>062-072>075-082>085.
Wind Chill Advisory from midnight tonight to noon CST Friday
for NEZ039>041-046>049-060>064-072>077-082>087.
Wind Chill Warning from 6 PM Friday to noon CST Tuesday for
NEZ039>041-046>049-060>064-072>077-082>087.
Winter Storm Warning from 3 PM this afternoon to noon CST
Friday for NEZ041-048-049-063-064-076-077-086-087.
KS...Winter Weather Advisory from 3 PM this afternoon to noon CST
Friday for KSZ005>007-017>019.
Wind Chill Advisory from midnight tonight to noon CST Friday
for KSZ005>007-017>019.
Wind Chill Warning from 6 PM Friday to noon CST Tuesday for
KSZ005>007-017>019.
&&
DISCUSSION...Pfannkuch
AVIATION...ADP
CLIMATE...Pfannkuch