Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/15/25
Area Forecast Discussion
National Weather Service La Crosse WI
1001 PM CST Tue Jan 14 2025
.KEY MESSAGES...
- Confidence is increasing (30-70% chance) for snow showers late
tomorrow afternoon and into the overnight, primarily east of
the Mississippi River. Accumulations of a trace to 1" will be
possible.
- Above normal temperatures expected for Thursday and Friday
with highs generally in the 30s and 40s across the entire
area.
- Very cold temperatures are likely next week with morning low temperatures
on Monday and Tuesday (40-90% chance) falling to -10F or
colder with wind chills below -25F.
&&
.DISCUSSION...
Issued at 151 PM CST Tue Jan 14 2025
Rest of Today - Wednesday Morning: Continuing Cold
GOES-16 water vapor imagery and 500mb heights today depict a
departing shortwave trough with north/northwesterly flow in its
wake. With weak divergence in place overnight, minimal sky cover and
relatively lighter winds enabled temperatures to once again plummet
this morning with many locations falling below -10F and below zero
temperatures areawide. Based on 850mb temperature fields in the
14.09z RAP of -20C earlier today, expecting somewhat similar
conditions to the previous with highs generally in the upper single
digits to middle teens. While the coldest axis of 850mb temperatures
shifts eastward overnight, light surface winds and clear skies will
allow our region to drop once again with lows falling to around 0
into Wednesday morning outside of typical cold spots in Central
Wisconsin which may drop further.
Wednesday - Friday: Warmer End to the Week, Wednesday Snow Chances
As we head into Wednesday, a weak shortwave trough will sneak
through the Upper Midwest with attending warm air advection in the
low-levels. As associated low-level frontogenesis pushes through the
area during the late afternoon and evening hours on Wednesday, this
forcing and modestly steep low-level lapse rates will instigate some
flurries/snow showers throughout the day. As a result, have
increased precipitation chances for much of the area during this
timeframe as much of the recent CAMs support this notion. This is
further support by the 14.12z HREF which has modest probabilities
(30-80% chance) for seeing measurable QPF. P-type generally would be
snow with this and while there is some question further southwest
where a drier layer can be noted in the dendritic growth zone across
southeast MN, the fairly robust forcing with the low-level warm
advection would likely be enough to maintain saturation into the DGZ
and make freezing drizzle more patchy in nature if it does occur. In
any case, expecting accumulations of a trace to 1" for the area,
primarily east of the Mississippi River. Would not rule out some
amounts of over 1" given that the 14.12z HREF has some low-end
probabilities (10-30%) for over 0.1 of QPF" north of I-94, when
combined with snow ratios of slightly above climatology of 15-17:1.
Looking at Thursday and Friday, the upper-level pattern changes
briefly with a decent ridge swinging through. Given the previously
mentioned warm advection and southwesterly surface flow, expecting
temperatures to warm fairly considerably with median high
temperatures in the 14.00z grand ensemble (GEFS/EC ens/Canadian ens)
generally in the middle 30s to middle 40s for Thursday and Friday.
This Weekend and Next Week: Very Cold Temperatures
Saturday will feature a very profound airmass change as a fairly
strong upper-level trough will push through the region during the
pre-dawn hours, issuing strong cold air advection and northwesterly
flow. Consequently, expecting afternoon temperatures only in the
upper single digits to middle teens with temperatures falling
throughout the day and into the evening. By the time Sunday morning
rolls around, the entire area will likely fall below zero for air
temperatures with medium probabilities (30-60%) in the 14.00z grand
ensemble for wind chills below -25F. As we start the new week, this
arctic airmass situates directly overhead with 850mb temperatures of
-30C progged across deterministic guidance (GFS/EC). The coldest
period will likely be Sunday through Tuesday with robust
probabilities (40-90% chance) in the 14.00z grand ensemble for
morning air temperatures on Monday and Tuesday to fall into the
negative double digits areawide and for wind chills under
-25F. There are even some low probabilities (10-40%) for wind chills
under -35F, so certainly the potential exists for this to be a
hazardous stretch of cold.
&&
.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1000 PM CST Tue Jan 14 2025
VFR conditions through Wednesday morning expected. MVFR clouds
move in from northwest to southeast across the area during
Friday afternoon and evening. Accompanying these lower CIGS
will be a good chance of snow showers to occur. The area with
the best chance at seeing snow showers will be along and north
of I-94. There will be lower chances at seeing some snow showers
in southeast Minnesota, western Wisconsin, and northeast Iowa.
Have gone ahead and continued the PROB30 for both KRST and KLSE
for this potential during the evening. Light southerly winds
will continue into the morning then increase by the afternoon
with gusts up to 25 mph.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Naylor
AVIATION...Cecava
Area Forecast Discussion
National Weather Service North Platte NE
548 PM CST Tue Jan 14 2025
.KEY MESSAGES...
- Intermittent light snow remains possible this afternoon for
the northern Sandhills but little to no impacts are expected.
- Mild temperatures are expected each day Wednesday and Thursday with
afternoon highs likely in the upper 40s to low 50s, or 15 to
20 degrees above normal.
- A strong cold front arrives Friday and subsequent invading
Arctic high pressure will lead to plummeting temperatures with
forecast highs likely falling to around 30 degrees below
normal each day Sunday and Monday. Trends will be monitored
for potential cold weather headlines early next week.
&&
.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 258 PM CST Tue Jan 14 2025
A broad shield of cloud cover continues to shift south out of
western South Dakota into the local area. This is coincident with a
quick diving shortwave and departing trough axis to the south,
entering Kansas as of 20z. A secondary PV anomaly is apparent on
satellite moving north to south across the northern Plains and this
feature will arrive into the area later tonight into early
Wednesday. At the surface, a stationary boundary is stalled from
near IEN down through LBF with modest downsloping flow to the west
that has allowed for temperatures to jump into the lower and middle
30s whereas areas to the east remain in southerly flow and lack of
more appreciable subsidence is struggling to erode the low stratus.
This is resulting in a significant temperature gradient from west to
east where colder temperatures are holding firm in the lower teens.
For late this afternoon/tonight...modest convergence in the vicinity
of the stalled boundary may yield another brief period of light snow
for isolated areas. HRRR seems to be the most aggressive solution
depicting this but even so struggles to produce much if any QPF.
Can`t rule out some non-measurable snow but impacts are expected to
be limited if realized at all. Expect lows tonight to fall into the
teens. Early Wednesday as flow becomes more westerly across the
forecast area due to the frontal boundary shifting east, a small
area of weaker flow on the back edge of stratus may promote some fog
development. SREF/HREF probabilities for seeing < 1 SM visibilities
peak around 50-60% immediately east of the Highway 83 corridor. With
this in mind, leaned on HRRR simulated visibilities for addition of
Patchy Fog mention. These SREF/HREF probabilities quickly increase
towards midday so believe whatever fog that does develop will
dissipate and leave a fairly nice day Wednesday as a result. Did
bolster high temperatures slightly given good agreement in
statistical guidances and hi-res output all showing widespread 40s
to near 50. Lingering cold spots include the western Sandhills where
Tuesday snowfall may linger into the day and far north central
Nebraska where clouds may be slower to exit. Breezy west-northwest
winds will develop as a surface trough sharpens and shifts east.
Peak speeds will reach 25 to 30 mph factoring those into
temperatures, feels like values will hold firm in the middle 30s for
most and only low 40s for some. Only a slight improvement is
expected for Wednesday night lows as many locations hold onto the
20s and a few locations still fall into the teens.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 258 PM CST Tue Jan 14 2025
Thursday...Another mild day is expected as heights aloft peak thanks
to low-amplitude ridging moving in from the northwest. Continued
westerly low-level flow will promote mild temperatures. Winds
gradually back to the southwest as a stronger surface low takes
shape near the US/Canadian border. An attendant cold front will
begin to settle south out of the Northern Rockies and compressed
heights/pressure field ahead of this will support another breezy day
where winds approach 25 to 30 mph. The warmest day of the week is
anticipated with forecast highs climbing into the 50s for many and
middle to upper 40s elsewhere.
Friday through Monday...a fairly well advertised cold spell will
interrupt our mild stretch. As mentioned before, a strong cold front
trailing a deeper low pressure system across southern Canada will
approach from the northwest. The feature will be driven by strong
Canadian high pressure exceeding 1040 hPa and the 90th percentile in
NAEFS guidance. This high pressure will continue to sink south along
the lee of the Rockies with its influence gradually increasing in
the local area through Sunday morning. Ensemble guidance continues
to showcase large negative anomalies for temperatures through the
period. Meanwhile the ECMWF Extreme Forecast Index suggests values
in the -0.8 to -1.0 range, particularly for our western zones Sunday
and Monday. Non-zero shift of tails suggest a few members
advertising extreme values but lack of greater shift of tails values
limit confidence in seeing record setting cold. Even so, the cold
will be noteworthy and later forecast may require cold weather
headlines. Confidence in magnitude of cold casts some doubt though.
This is largely due to a glancing blow from the high pressure center
as opposed to direct track through the immediate area. Some subtle
differences in placement of said high pressure center between parent
EPS and GEFS solutions likely explain lingering uncertainty but even
the most optimistic solution suggests temperatures nearing 30
degrees below normal. This supports highs falling into the teens by
Saturday and single digits on Sunday and Monday. Overnight lows are
likely to fall below zero and into the negative teens for many
Sunday and Monday morning and it`s these periods that concern is
greatest for the need for cold weather headlines. Being Day 5-7,
will hold off for now and continue to monitor trends. Should the
current forecast hold, Cold Weather Advisories (-20 degF criteria)
will be needed possibly as early as Saturday morning but more likely
for Sunday morning and Extreme Cold Warnings (-30 degF criteria)
will need considered for Sunday and Monday mornings but confidence
in necessitating the latter of these is medium at best so stay tuned.
This incoming cold air will effectively squeeze what little moisture
is available as well and light snow is in the forecast mainly for
areas west of Highway 83. Ensemble guidance struggles to advertise
appreciable snow potential with probabilities of > 1" capped at
approximately 50% for our far western zones for 72 hours ending
Monday morning.
Tuesday and beyond...with high pressure now departing to the
east/southeast, reestablished southwesterly flow will promote
moderating temperatures. This will allow a return to seasonable and
then above normal temperatures beyond Day 7. Large spread with inner-
quartile values from the model blend casts some doubts on how much
warmer we actually get but even so believe the prospect of seeing a
return of temperatures above the freezing mark appears possible
Tuesday through the middle of next week. The latest Climate
Prediction Center outlook highlights the area with slight below
normal temperature probabilities favored but varying ideas from
EPS/GEFS solutions limit confidence in this and overall the idea for
near seasonable temperatures to return appears probable.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 547 PM CST Tue Jan 14 2025
For the KLBF terminal: Expect some broken ceilings around 4000
FT AGL to persist into the early overnight hours before
scattering out after 10z Wednesday. Expect a few to scattered
clouds with ceilings around 25000 FT AGL Wednesday morning into
the afternoon hours. For the KVTN terminal: Overcast ceilings
around 2500 FT AGL will increase to 6000 FT AGL by late evening,
remaining there into the overnight hours. Skies will scatter out
Wednesday morning with ceilings ranging from 20000 to 25000 FT
AGL. Some westerly wind gusts may approach 25 KTS Wednesday
afternoon at the KVTN terminal.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...NMJ
LONG TERM...NMJ
AVIATION...Buttler
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
609 PM CST Tue Jan 14 2025
.KEY MESSAGES...
- Late Wednesday/Night, increasing chances for light snow north
of I-94, with light accumulation near a half inch or less.
- Thursday and Friday, warmer with highs in the low to mid 30s.
- Saturday, another surge of Arctic air arrives, continuing into
next week. Cold Weather Advisories may be possible, but
extreme cold warnings are unlikely.
&&
.DISCUSSION...
Issued at 1236 PM CST Tue Jan 14 2025
Today through Wednesday night... Early morning satellite imagery
and surface obs showed clear skies across the region, with light
northwest winds becoming nearly calm. A surface high was
centered across the region, and this high will shift eastward
later today and overnight. As it does, southwest winds will
develop on the back side, and on Wednesday could see gusts of 20
to 25 mph.
These southwest winds will be ahead of a surface trough that
will pass through the region as an upper level wave skirts
across the northwest. The strongest forcing with this wave will
be along the International Border, but forecast soundings do
show lift and saturation at the sites along and north of I-94.
For that reason, did increase pops, especially east of I-35 and
north of I-94, where the HiRes models are in good agreement in
bringing a few hours of snow. Snowfall amounts will be light,
generally less than a half inch, with the highest totals across
western Wisconsin.
Snow is expected to be the primary precipitation type, but
forecast soundings do show some mid-level drying and loss of ice
crystals. That means there could be some patchy freezing drizzle
at times. The HRRR tries to hint at this, but overall the HiRes
models are showing mainly snow. The thing is, they were showing
mainly snow Saturday evening as well, when there was freezing
drizzle across the Metro.
Thursday through Tuesday...A January thaw will commence later
this week as warmer air moves across the region. Highs will be
in the low 30s on Thursday, and a few degrees warmer on Friday.
Winds will be light on Thursday and Friday morning, but this
reprieve from winter will be short-lived as a cold front pushes
through the region late Friday, and brings another blast of
arctic air that will last into early next week. Saturday will be
blustery with highs occurring in the morning, and steady or
falling temperatures the rest of the day. The coldest days will
be Sunday and Monday, when highs will remain below zero, and
overnight lows will be -15 to -20 degrees. The combination of
cold temperatures and steady northwest wind will likely lead to
another round of Cold Weather Advisories for both Sunday and
Monday morning, possibly Tuesday as well. At this time, Extreme
Cold Warnings are not expected. Wind chills of -25 to -35 are
most likely, and locations that fall to near -40 have a higher
threshold. A few snow showers are possible at times given the
cold air mass, but little to accumulation is expected next
week.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 556 PM CST Tue Jan 14 2025
Clear skies will continue through early tomorrow with light
winds as a surface high sits over the region. Clouds and winds
will both be on the increase by mid morning ahead of a quick
moving disturbance. VFR should hold through the majority of the
period, but MVFR cigs are expected by late afternoon. Winds will
be generally southwesterly with gusts of 20-25kts late morning
through the end of the period. Our Wisconsin sites will likely
see light snow move in by late afternoon with MVFR conditions,
while some flurries are possible at KSTC and KMSP.
KMSP...Left out any mention of precip based on current
forecasts, but a few hours of light snow may need to be added
late tomorrow afternoon/evening with the next set of TAFs.
Otherwise, winds are expected to increase out of the southwest
around 15z and shift more westerly by 00z. MVFR cigs are also
anticipated around 00z through the end of the forecast period.
/OUTLOOK FOR KMSP/
THU...VFR, chc MVFR. Wind NW at 10G15kts.
FRI...VFR, chc MVFR. Wind W at 5kts bcmg NW at 15G25-30kts.
SAT...VFR. Wind NW at 15G25kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
DISCUSSION...JRB
AVIATION...Dye
Area Forecast Discussion
National Weather Service Marquette MI
720 PM EST Tue Jan 14 2025
.KEY MESSAGES...
- Lake effect snow transitions to the NW wind belts tonight,
with generally an additional 4 inches or less expected. Lows
in the interior west tonight range from 0 to -10F.
- Southwest gales of 35 to 40 knots over western Lake Superior
Wednesday into Wednesday evening.
- Bitter cold arctic air settles into the area this weekend into
early next week, leading to the potential of temperatures
remaining subzero Saturday night through at least Tuesday
morning over interior western Upper Michigan.
- Aside from a couple weak clippers, snow will be primarily lake
effect into the weekend and early next week. Mini whiteouts
and very hazardous driving conditions in the northwest wind
snow belts will be possible Saturday into next week.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 216 PM EST Tue Jan 14 2025
Early afternoon water vapor imagery and RAP analysis shows an upper
low centered near Quebec City with troughing extending SWwd into
lower MI and WI. Upstream, anomalous ridging extends from the EPac
NEwd across western Canada into Nunavut. Midlevel flow with a
northerly component exists over the local area in between these two
major features. At lower levels, a pocket of cold air at 850 mb of
minus 15 to minus 20C is crossing Lake Superior, resulting in
sufficient instability for lake effect snow showers. Moderate to
locally heavy banding has occurred through the morning from eastern
Marquette County eastward to Munising thanks to a
troughing/favorable convergent wind pattern over the eastern half of
the lake along with lift in the saturated convective dendritic
growth zone near the surface. Steadiest band has been in the Skandia-
Carlshend area where I would not be surprised to see some totals
around 6 inches. Have had a couple reports of around 4 inches at WFO
MQT and Marquette Township. The Winter Weather Advisory was extended
to 21Z given the ongoing activity.
Heights gradually building and low-level winds backing should
continue to push steadier bands eastward with time through the day
and into tonight. Surface high pressure will build from the northern
Plains into the Ohio Valley, with ridging extending northward into
the UP. Return flow may develop late ahead of the next approaching
wave in NW flow. This should push LES bands more or less just about
completely offshore by 12Z Wednesday, although a little convergence
may linger over Luce County and the Keweenaw. However, the LES that
exists through the night should be more or less constant based on
inversion heights not changing much until after 06Z. Overall, expect
an additional 2-4, locally to 6 inches over Alger/N.
Schoolcraft/Luce through tonight, with 3 inches or less over the
west and Keweenaw. Outside of the LES belts, low temps will be
tricky as there may be a window for some good radiational cooling
before the return flow kicks in over the interior west. Went colder
than NBM toward the 10/25 percentiles here, yielding lows of 0 to -
10F, and wind chills approaching -20F. Over the east and lakeshores,
expect lows 0 to 10F.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 141 PM EST Tue Jan 14 2025
Upper air pattern consists of a rex block on the west coast, a
shortwave near Lake Winnipeg and a shortwave over the central plains
and a closed low in the Canadian Maritimes 12z Wed. The Lake
Winnipeg shortwave moves into the upper Great Lakes 00z Thu and into
the lower Great Lakes by 12z Thu. Shortwave ridging moves into the
upper Great Lakes 12z Fri and then another shortwave moves into the
upper Great Lakes late Fri. Have next clipper system snow moving
into the area Wed afternoon and the LES for Wed night into Thu.
In the extended, the GFS, ECMWF and Canadian all show a 500 mb ridge
off the west coast and a broad and deep trough across most of the
rest of the U.S. 12z Sat. The trough amplifies 12z Sun and the
trough remains over the area into Tuesday. Temperatures will stay
well below normal for this forecast as cold air moves across the
region starting on Saturday and WNW wind belt lake effect snow
showers will be the rule for this period. Also looks like some
headlines for LES and cold weather will probably be needed at some
point as well.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 719 PM EST Tue Jan 14 2025
MVFR conditions have returned to all TAF sites with a general trend
toward VFR by tomorrow. Nonetheless, will continue to carry PROB30s
to account for any flight restrictions in periodic lake effect
snow showers tonight and tomorrow. Other impacts include strong
southwest winds starting tomorrow morning at IWD and CMX with
gusts of 25 to 30 kts.
&&
.MARINE...
Issued at 141 PM EST Tue Jan 14 2025
An active pattern is expected in this forecast period thanks to
strong pressure gradients associated with passing clippers and
continued and deepening cold air building over the region. The wind
will be 20 knots or less for most of tonight before increasing to 15
to 25 knots late from the west and southwest. Southwest gales to 35
to 40 knots are expected Wednesday into Wednesday evening across the
west half of Lake Superior. Northwest winds to 30 knots continue
late Wednesday night into Thu before dropping off below 20 knots Thu
night. Next gale event occurs Friday into Saturday morning with
southwest to west gales of 35 to 45 knots expected. These stronger
winds and continued colder air over the region will support periods
where ice growth from freezing spray will be possible. Expecting low
to moderate freezing spray rates primarily, but the increasingly
colder air building into the region this weekend may support heavy
freezing spray rates.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Warning from 10 AM EST /9 AM CST/ to 10 PM EST /9 PM CST/
Wednesday for LSZ162.
Gale Warning from 10 AM EST /9 AM CST/ Wednesday to 1 AM EST
/midnight CST/ Thursday for LSZ241>244-263-264.
Lake Michigan...
None.
&&
$$
SHORT TERM...Thompson
LONG TERM...07
AVIATION...TDUD
MARINE...07