Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/18/24
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
825 PM CST Wed Jan 17 2024
.KEY MESSAGES...
* Two systems will bring light snow to the area the next few days,
with the second one (Thursday night) the more impactful of the
two.
* Another period of dangerous wind chill follows this system,
beginning as early as Friday morning.
* Rain initiates a significant warming trend early next week,
though there is a 20-40% chance of it being accompanied by some
light icing.
&&
.UPDATE...
Issued at 818 PM CST Wed Jan 17 2024
This evening, regional radar mosaic is showing broad, weak returns
across much of Iowa, northern Missouri, and portions of central and
northern Illinois. This is mainly in response to weak mid-level
isentropic ascent along the 290-295K surfaces. Despite the radar
presentation, regional obs show little of this reaching the surface
with only a couple light snow reports noted over central Iowa. This
is not surprising given the 00Z KILX sounding showing a deep
layer of dry air from the surface up to around 600mb. RAP suggests
forcing from weak, transient frontogenesis may help overcome the
dry air late this evening and overnight near the I-74 corridor.
Any accumulations in that area are still expected to be light,
less than an inch, though most areas will probably only see
flurries.
Deubelbeiss
&&
.SHORT TERM... (Through Late Thursday Night)
Issued at 249 PM CST Wed Jan 17 2024
Mid level cloud deck has been pushing east across the forecast
area today, with a fair amount of sunshine early this afternoon
from west central into southeast Illinois. Temperatures have
managed to get into the 20s over the forecast area, a nice change
of pace from the last several days, with even a few lower 30s
south of I-70.
Main forecast challenge during this period remains with the two
separate periods of light snow.
Morning model suite shows forcing beginning to take place along
the I-80 corridor this evening, with a general increase in light
snow after midnight as a surface boundary passes through central
Illinois. Forecast soundings show a fairly dry layer below 5,000
feet a good chunk of the night, which will eat into the overall
snow totals the further south you go. Some banding is suggested
in some of the high-res models runs which may compensate, but
morning HREF guidance only shows about a 10-20% chance of
receiving over an inch of snow. Will continue with some 60% PoP`s
overnight into early Thursday east of I-39 to near Decatur and
Danville, with most areas south of I-70 missing out on the first
round.
A lull in the precipitation is expected late Thursday morning
through the afternoon, before a stronger wave dives southeast
toward Illinois. This feature has been trending faster and a bit
heavier with the amounts, with about a 30-40% chance of over 2
inches north of I-74 per HREF ensembles. Snowfall rates of a
quarter to half inch per hour are suggested. While a widespread
blowing snow situation is not expected, snow/liquid ratios in the
order of 18:1 or so suggest a fluffier snow which may drift a bit
as northwest winds start gusting to around 25 mph or so. Though
the highest amounts are expected north of I-74, even the southeast
CWA should be able to squeeze out about a half inch of fluff.
Geelhart
.LONG TERM... (Friday through Next Wednesday)
Issued at 249 PM CST Wed Jan 17 2024
The next round of Arctic air will follow this front, with wind
chill advisories anticipated to be issued for much of the area at
some point on Friday, at least north of I-70. With the faster
speed, this may be needed as early as Friday morning west of the
Illinois River, though the most widespread -15F wind chills
hold off until evening. At the moment, it is expected that high
pressure building into the Mississippi Valley will drop off winds
enough so that Saturday night isn`t quite as bad. However, with
some fresh powder on top of the original 6+ inch snow depth
northwest of the Illinois River -- in an area which will also drop
well below zero -- it won`t take much wind to get back into
advisory territory.
After that, a large scale pattern change takes place, as the upper
flow comes off the Pacific. This will initiate a much milder
weather pattern for next week. There remains some concern that the
strong warm air advection with the cold ground may result in some
icing issues with freezing rain on Monday. Latest NBM guidance
show about a 30-40% chance of light freezing rain near/west of
Springfield Monday morning and around a 20-25% chance into the
afternoon in most areas north of I-70. However, nearly half the
GEFS/EPS ensemble members are coming in dry during the morning,
and suggest more of a precipitation surge Monday night.
Temperatures will still be near freezing then, so icing still
remains a concern, though if the rain falls heavy enough, that may
be enough warm temperatures near the ground to compensate for the
frozen soil or lingering snow cover. For now, the forecast will
continue to mention rain or freezing rain Monday and Monday night,
with high chances (50-60%) of regular rain Tuesday into Wednesday.
Temperatures by mid week are expected to be in the 40s over the
forecast area, and the new CPC outlook for January 23-27th
highlights a >80% chance of above normal temperatures during that
period.
Geelhart
&&
.AVIATION... (For the 00z TAFs through 00z Thursday Evening)
Issued at 525 PM CST Wed Jan 17 2024
Light southerly winds less than 10 kt and VFR conditions will be
in place this evening and some of the overnight hours. Late
tonight, an upper level disturbance will bring light snow and
flurries to portions of the I-74 corridor. The best chance for
MVFR ceilings will be near the end of the light snow Thursday
morning as winds become light and variable.
Deubelbeiss
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Omaha/Valley NE
518 PM CST Wed Jan 17 2024
.KEY MESSAGES...
- Light snow possible (20-30% chance) tonight with accumulations
of less than 1 inch expected.
- Widespread light snow (50-90% chance) Thursday afternoon into
early Friday morning. Accumulations expected to remain between
2 and 3 inches with the heaviest snowfall in northeast
Nebraska. Blowing snow is possible Friday morning.
- Dangerous cold returns late this week with wind chills diving
into the -20 to -30 range Friday morning and -30 to -35
Saturday morning.
- Warm weather expected at the start of next week.
&&
.DISCUSSION...
Issued at 351 PM CST Wed Jan 17 2024
Tonight through Saturday:
The upper level trough that brought much of our impactful weather
last week is making its way off the Eastern Seaboard. This leaves us
with moderate westerly flow aloft and a slight improvement in our
chilly temperatures with Thursday highs in the low 20s. A shortwave
trough traversing off the Northern Rockies and towards the Central
Plains will bring us a chance for light snowfall this afternoon into
evening. PoPs remain low (20-30%) with flurries to a light dusting
of snow possible. Impacts are limited to a few slick spots as
accumulations remain below an inch.
A second shortwave trough is making its way onshore towards the
Pacific Northwest before its arrival over the Northern Plains
Thursday afternoon into the evening. A band of snow producing 2 to 4
inches of snowfall looks to be setting up over southeast South
Dakota and dipping into northeast Nebraska. A fair amount of spread
is still present between model guidance on where this band of heavy
snowfall will set up. 12Z runs of the ECMWF and NAM position the
band from north central into northeastern Nebraska. Meanwhile, the
12Z and 18Z HRRR pushes the heaviest band northeast into SD/MN/IA,
leaving reduced accumulation for much of the area. Latest runs of
the NBM continue to show this slight push to the northeast. Strong
snowfall production in the dendritic growth zone will also bring
high SLRs with this event. SLRs are expected around 20:1, bringing
light and fluffy snow.
With these factors considered, the highest expected snowfall totals
has made a slight jump in intensity and shift to the northeast.
Northeast Nebraska is currently expecting 2 to 3 inches with values
decreasing further southwest. This leaves both the Omaha and Lincoln
metropolitan areas with an expected 1 to 2 inches. Snow is expected
to begin Thursday afternoon before wrapping up early Friday morning.
In terms of impacts, strong northwesterly winds will move into
northeast Nebraska just as the snowfall begins to slow on Friday
morning. Gusts up to 35 mph are possible Friday morning, leading to
concerns for blowing snow and reduced visibilities. With a thick
snowpack and large drifts still present in much of northeast
Nebraska, this could lead to dangerous travel concerns and possible
road closures, especially in rural areas. With this considered, a
Winter Weather Advisory has been issued for the majority of the CWA
from noon Thursday through 6 AM Friday. We will continue to monitor
the possibility of upgrading to a Winter Storm Warning in our
northern counties (particularly Knox, Cedar, Thurston, Pierce, Wayne,
Cuming and Burt) where winds are the strongest and blowing snow
concerns remain the greatest. As a decent crust is currently present
on the snowpack in this area, confidence will need to be gained in
these areas receiving two inches of snow or greater before
upgrading.
As an upper level trough deepens over Ontario/the Great Lakes
region, strong northwesterly flow will bring another arctic airmass
and bitter cold temperatures to the region. A Wind Chill Advisory
has been issues for the entire CWA for Thursday night into Friday
morning with wind chill temperatures expected in the -20 to -30
range. Winds will be considerably lighter on Saturday (5 to 10 mph),
prompting a Wind Chill Watch to be issued for Friday night into
Saturday morning. Low temperatures Saturday morning are expected to
linger around -20 with wind chills expected around -30 to -35.
Saturday minimum temperatures have the potential to break Lincoln`s
record minimum temperatures of -18 set in 1888. Omaha will be
nearing its record minimum temperatures of -22, set in 1883.
Sunday through Tuesday:
Upper level riding and southwesterly flow will return Sunday,
bringing "warm" temperatures back to the region. Highs on Sunday
will remain in the mid to upper 20s. Monday through Wednesday will
see slightly above average temperatures with highs in the mid 30s.
This increase in temperatures will begin melting away at the
snowpack that has accumulated over much of eastern Nebraska and
western Iowa. There is a small possibility of precipitation over
southeast Nebraska Monday night into Tuesday as a shortwave trough
ejects over the Central Plains. However, confidence is very low in
this extended time frame and it will continue to be monitored as it
approaches.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 506 PM CST Wed Jan 17 2024
From the beginning of the TAF forecast period through 09Z
tonight, there is a low chance (20-35%) of light snow stretching
from northeast Nebraska into southwest Iowa (including KOFK and
KOMA). Precip probs are too low to include in TAFs at this
time. After 12Z, more widespread snow will move into the region
from the northwest. MVFR cigs will likely precede snow by 2-3
hours. Heaviest snow will likely be after 17Z. With high SLRs
and wind gusts increasing close to 30 knots by the end of the
TAF period, occasional LIFR visibilities will be possible after
21Z, especially across northeast Nebraska (KOFK). However,
persistence and confidence is not enough to be included in TAFs
at this time.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Winter Weather Advisory from noon Thursday to 6 AM CST Friday
for NEZ011-012-015>018-030>034-042>045-050>053-065>068-
090-091.
Wind Chill Advisory from 6 PM Thursday to noon CST Friday for
NEZ011-012-015>018-030>034-042>045-050>053-065>068-078-
088>093.
Wind Chill Watch from Friday evening through Saturday morning
for NEZ011-012-015>018-030>034-042>045-050>053-065>068-
078-088>093.
IA...Winter Weather Advisory from noon Thursday to 6 AM CST Friday
for IAZ043-055-056-069-079-080-090-091.
Wind Chill Advisory from 6 PM Thursday to noon CST Friday for
IAZ043-055-056-069-079-080-090-091.
Wind Chill Watch from Friday evening through Saturday morning
for IAZ043-055-056-069-079-080-090-091.
&&
$$
DISCUSSION...Wood
AVIATION...Darrah
Area Forecast Discussion
National Weather Service Paducah KY
523 PM CST Wed Jan 17 2024
.KEY MESSAGES...
- A wintry mix will impact portions of the region late Thursday
morning into Thursday evening. Light freezing rain and
drizzle is now the main concern versus snow as temperatures
struggle to rise above freezing. Hazardous travel conditions
are expected for the Thursday evening commute, and may linger
into the Friday morning commute. A Winter Weather Advisory has
been issued.
- Another disturbance may bring some additional light snow
across the north in portions of southern Illinois and
southwest Indiana late Thursday night into early Friday
morning. Minor snow accumulation is possible.
- Dangerous cold temperatures return behind a front Thursday
night with wind chill values once again falling below
freezing through Saturday night, and near -10 or below Friday
night.
- A significant warm up begins Sunday and continues into next
week, but the pattern quickly turns unsettled with daily
chances for rain.
&&
.UPDATE...
Issued at 522 PM CST Wed Jan 17 2024
Updated Aviation discussion for the 00z TAF issuance.
&&
.DISCUSSION...
Issued at 334 PM CST Wed Jan 17 2024
Southerly return flow on the backside of sfc high pressure over the
Tennesse Valley has allowed for maxTs to warm near the freezing mark
for the first time since Saturday. Although tonight will still be
quite cold, minTs are progged to fall to only near 20 with wind
chill values above 0 as high clouds begin to increase ahead of the
next system. MaxTs on Thursday will be similar to today near
freezing.
The next system on Thursday ahead of a cold front is turning out to
be quite a mess from a forecast perspective as the 12z deterministic
models have been able to fully sample a 500 mb shortwave that is now
over land in the western CONUS. This energy combined with isentropic
lift associated with 850-700 mb WAA will cause pcpn to develop late
Thursday morning and continue into the afternoon across portions of
southeast Missouri, western Kentucky, and southwest Indiana. Light
freezing rain/drizzle is now turning out to be the main concern
versus snow as BUFKIT model thermal profiles lack saturation in the
DGZ, but show a saturated column below 800 mb. However, the CAMs are
split with the western and northern extent of QPF with the HRRR
being the worse case scenario for freezing rain. If snow occurs, it
would be brief on the onset as the mid-levels dry out quickly. For
this reason, have limited NBM wxType snow to just a slight chance
for most locations.
As for impacts, confidence is the highest southeast of a line from
Mayfield to Madisonville in seeing a glaze of ice and perhaps some
minor snow accumulations. This is where the HREF has a 60-80%
probability while areas to the NW along the Ohio River are in the 20-
40% range due to more uncertainty. Even if areas to the NW miss out
on the steadier pcpn, freezing drizzle would still be a concern and
can be just as dangerous when it comes to travel impacts! Given that
ground temperatures are extremely cold, it will not take much for
icy and slippery conditions to develop, even if the air temperature
briefly rises above freezing in the afternoon. By Thursday evening,
there will be a brief window for freezing drizzle to continue before
pcpn tapers off as a cold front approaches. Given the potential for
hazardous travel conditions for the Thursday evening commute that
may also linger into the Friday morning commute, have issued a
Winter Weather Advisory after collaboration with our WFO neighbors.
To make things even more complicated, another 500 mb shortwave that
is currently located over British Columbia Canada will bring the
potential for another round of pcpn in the form of light snow late
Thursday night into early Friday morning across our northern
counties in southern Illinois and southwest Indiana. There is some
uncertainty in the southern extent of pcpn as some of the model
guidance is showing very little. Although QPF will only be a couple
hundreths at most, a DGZ below 900mb combined with high SLRs around
18:1 behind the aformentioned cold front will support a quick
coating to half of an inch, with localized higher amounts closer to
one inch not ruled out mainly in southwest Indiana. The snow
character will be extremely dry, so any brief snow that does fall
will be able to quickly cover all surfaces.
With that said, the other concern will be another round of dangerous
cold temperatures as wind chills once again will fall below freezing
Thursday night and Saturday night. Meanwhile, Friday night wind
chills could fall below -10 across a large portion of the CWA into
Wind Chill Advisory criteria. Otherwise, dry conditions are in store
for the weekend as a 1040 mb sfc high pressure builds over the FA.
By Sunday, heights aloft will rapidly rise as a big warm up is in
store into next week with maxTs potentially reaching the 50s by the
middle of the week. unfortunately, the pattern looks to be quite wet
and unsettled with daily chances for rain Monday through Wednesday.
NBM still indicates the potential for a brief wintry mix Monday
morning across portions of southeast Missouri and southern Illinois
as the cold air retreats, but right now confidence is low in seeing
any impacts.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 522 PM CST Wed Jan 17 2024
Tricky forecast, with the potential for a wintry mix of FZRA,
IP, or SN possibly reaching far enough north to impact PAH and
OWB after 15z. For now, confidence was too low to include a
mention of anything more than VCSH, but this may change with
future forecasts.
Otherwise, expecting lowering high and mid-level bases
overnight, with MVFR cigs arriving after 18z at OWB and PAH.
Winds will be steady from the S-SW at 5-10 kts.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...Winter Weather Advisory from 10 AM Thursday to 9 AM CST Friday
for MOZ112-114.
IN...Winter Weather Advisory from 10 AM Thursday to 9 AM CST Friday
for INZ087-088.
KY...Winter Weather Advisory from 10 AM Thursday to 9 AM CST Friday
for KYZ001>022.
&&
$$
UPDATE...DWS
DISCUSSION...DW
AVIATION...DWS