Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/19/25
Area Forecast Discussion
National Weather Service La Crosse WI
1043 PM CDT Tue Mar 18 2025
.KEY MESSAGES...
- HIGH IMPACT winter storm to hit the area Wed. Slight southeast
shift in storm track bringing heaviest snow across parts of
southeast MN through northeast WI.
- Snow amounts of 8+" in the narrow snow band, but could be
locally higher. 1" per hour rates in this band with the bulk
of the snow falling Wed afternoon.
- Strong northerly winds 15 to 30 mph with gusts 35 to 50 mph; highest
across the open areas of SE MN/NE IA.
- White-out conditions possible where heavier snow and strongest
wind overlap. The wetter nature of the snow will limit
additional significant visibility impacts.
- A variety of winter weather headlines are in effect. Could be
some adjustments based on changes to the storm track. Keep a
very close on the forecast.
- Cooler Wednesday Night Through Thursday, Increased
precipitation potential Sunday.
&&
.UPDATE...
Issued at 933 PM CDT Tue Mar 18 2025
The latest surface analysis showed and elongated area of low
pressure from the Plains to the Mid-Mississippi Valley and lower
Great Lakes with a 980mb low over central Kansas. The front was
near Des Moines to Dubuque with strong northeast winds north of
the front and temperatures in the 30s/40s/50s from north to
south across the local forecast area. Near Des Moines,
temperatures were in the 60s. Surface dewpoints were only in the
20s and 30s locally with 40s across southern Iowa. The 500mb
closed low was over eastern Colorado.
The 00Z data is still coming in, but over the next 12hours,
we`ll see the closed low move eastward toward northeast Kansas
and intense moisture transport northward across the Plains into
the Mississippi Valley with the strengthening 50 to 80kt 850mb
jet. Should see precipitation starting to get going over the
next couple of hours in the Plains and after 06Z in western
Iowa. There was a slight shift southward during the day and the
preliminary 19.00Z NAM data continues its southward shift. The
00Z HRRR also is slightly farther south, but with somewhat
reduced amounts. As more information arrives, further
adjustments may be needed to our current headlines.
&&
.DISCUSSION...
Issued at 241 PM CDT Tue Mar 18 2025
HIGH impact early spring/late winter storm set to bring a cacophony
of weather impacts to the region Wednesday: heavy wet snow for some,
wide spread rain for others, strong winds for all (very strong for a
few), and the potential for white-out/blizzard conditions where the
heavy snow/strongest winds overlap.
Forecast Changes:
Short range guidance has shown a slight shift southeast with
the storm track - with impacts to where the heavy snowband lays
out. Latest CAMS and medium range models now suggest the band
will run from central IA northeast into northeast WI.
Forecast Setup:
No change with the models lifting an upper level shortwave
trough out of the desert southwest today, driving it across the
mid mississippi river valley by 18z Wed and exiting east
overnight. At the sfc, good agreement between the GEFS and EPS
with placement of the storm`s sfc low with a tight clustering of
nearly all the models` members across southeast IA at 18z Wed
and very similar strengths. As mentioned though...there has been
a slight shift in the track - and thus the deformation region
of the storm lays out from north central IA into northeastern
WI. Northwest-southeast running time/height x-sections in all
the models show sloping, hefty Fgen forcing, focused in the
deformation region. In addition, left exit region of a 100 kt
300 mb jet sets up over this same area for the morning, early
afternoon hours, further deepening the already strong lift. In
addition, there could be some convective elements within the
band while CAMS models also depict a smattering of convection
(moreso rain - potential thunder) over parts of far northeast
IA/southwest WI for the afternoon - on the northward edge of
weak instability.
Snow Details:
Change in the storm shifts the heavy snow band a bit southeast,
with higher end amounts/impacts now anticipated across
southeast MN into northcentral WI. While snow-liquid ratios will
likely start out around 6:1, increasing to 12:1 (or so) moving
into the afternoon...the amount of deep lift makes 1 to 2" per
hour rates likely within the narrow snow band. The greatest
lift/QPF and track of the storm would drop much of the snow from
late morning through the afternoon hours. Most of the
accumulations will be over by early evening.
Temperatures and compaction will work against some accumulations, but
the snow rates will easily overcome any melting. Differences in
elevation will be evident (more snow on ridge tops, less in the
valleys).
For anomalies, the EFIs are pushing 0.80 in the band for the local
area but with a SoT now of 1. Shining an even brighter light on the
higher end/higher impact potential for wet snow.
Overall, still looking for the potential for 8+" in the heart of the
band. If SLRs are higher, and/or the higher snowfall rates linger
even an hour or two, a few more inches could be realized.
It`s a tough system to nail down given the narrow nature of the
expected band, some shift southeast now, and wet/mild nature of the
airmass favoring lower SLRs while the strong lift could push it
higher. It`s also going to fall during the day and its mid Mar, not
mid Jan. Expect further refinement to the snow amounts - and the
potential for a further dip southeast.
Wind Impacts:
Strong/gusty winds will accompany this storm, looking strongest
west of the the Mississippi river, especially across parts of
IA. A 50-60 kt low level jet progged to scream south/southwest
down the backside of the trough Wed. The strongest of these
winds may ride just above the near sfc inversion, as evident in
the RAP/HRRR soundings, but momentum transfer still suggests at
least 40+ kts of wind could make the sfc in favored areas. HREF
probabilities are even higher with 80+ % for 50 mph wind gusts
for portions of SE MN/NE IA from late morning through the
afternoon.
Wind impacts on snowfall will be more related to when/where the snow
if falling. After it hits the ground, the heavy nature of the snow
will be hard to move. Could get some drifting here and there, but
even these winds will be hard pressed to lift the fallen snow high
enough for significant vsby impacts.
Cooler Wednesday Night & Thursday:
As Wednesday`s storm system exits, a quick bout of cold air brings
temperatures slightly below normal with overnight lows near 20 and
Thursday`s high near 40. The progressive pattern continues for the
latter half of the week as the ridge/trough pattern from the Rocky
Mountain West into the eastern Pacific Ocean on afternoon GOES water
vapor imagery phases through the central CONUS. Resultant temperatures
hover above and below 50 for daytime highs through the weekend.
Although, given the near term synoptic unpredictability and
dependence on exit behavior of the responsible extratropical
cyclone, there is much to shake out into the weekend.
Light, Minimal PoPs Friday:
Both the GEFS (18.12Z) and EPS (18.12Z) have increased confidence
for a mid level synoptic trough progressing from the Northern
Plains through the Upper Mississippi River Valley on Friday
according to location of the 540 dam isoheight. Agreement wanes
when investigating associated return flow and attendant moisture.
A quicker synoptic solution in both these long term global ensembles
has reduced local return flow, decreasing confidence for the 0.5"
PWAT by 10% each run; 10-40% in the most recent run(s). While overall
moisture will be less than previously forecasted, the increased confidence
in trough location has increased confidence for 0.01"+ QPF in both
the EPS (50-70%) and the GEFS (50-90%). Given above freezing temperatures
resulting in rain, longer forecast hour, and limited impacts, have
kept National Blend PoPs for now.
Precipitation Chances This Weekend:
The active pattern again ramps up through the weekend. A digging,
potentially closing, upper level perturbation progresses through the
Northern Plains early in the weekend according to global ensemble
confidence in the 540 dam isoheight. Current confidence places
this phasing directly across the forecast area. Unification of
subtropical energy out of the Southern Plains with this
extratropical energy exacerbates the unknowns. While both the
GEFS and EPS exhibit two areas of lower pressure, low center
locations varies from the International Border through Iowa. In
other words, there is little to no confidence for the
accompanying surface low within and between long term global
ensembles. Have continued with NBM PoPs of 50% and more for all
of Sunday. Confidence is high and has been increasing for 0.1"
of QPF during this time.
&&
.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1039 PM CDT Tue Mar 18 2025
VFR conditions currently present across the area. Deteriorating
conditions are expected early tomorrow morning as a winter storm
begins to move into the area. Ceilings will steadily begin to
lower before becoming MVFR/IFR around daybreak with CIGs in the
FL005-010 range by mid to late morning. These should linger
through the afternoon before clearing out to lower end VFR
generally between 00-06Z Thursday. Rain showers will begin to
impact the terminals early this morning. Intensity should
increase by mid morning with a wintry mix developing at KRST as
colder temperatures begin to funnel in. Precipitation should
transition over to snow around 15-18Z for the terminals where
blowing snow will be likely given the very gusty northerly winds
expected. This will make for very low visibilities (1/2SM or
worse) at the terminals, especially tomorrow afternoon when the
snow is expected to be at its heaviest. Winds will gradually
increase with peak gusts at the terminals in the 35-45 kt range
during the afternoon tomorrow. By the end of the period, winds
will gradually back more to the north-northwest and should be on
a downward trend, though gusts in the 25-30 kt range will still
be possible.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory from 7 AM to 7 PM CDT Wednesday for
WIZ041-042.
Winter Storm Warning from 7 AM to 7 PM CDT Wednesday for
WIZ017-029-032>034.
MN...Blizzard Warning from 7 AM to 7 PM CDT Wednesday for MNZ079-
086-087-094-095.
Winter Weather Advisory from 7 AM to 7 PM CDT Wednesday for
MNZ096.
Winter Storm Warning from 7 AM to 7 PM CDT Wednesday for
MNZ088.
IA...Blizzard Warning from 7 AM to 7 PM CDT Wednesday for IAZ008.
Winter Weather Advisory from 7 AM to 7 PM CDT Wednesday for
IAZ009-010-018.
Wind Advisory from 1 PM to 7 PM CDT Wednesday for IAZ019-029-
030.
&&
$$
UPDATE...Zapotocny
DISCUSSION...JAR/Rieck
AVIATION...Barendse
Area Forecast Discussion
National Weather Service Cheyenne WY
610 PM MDT Tue Mar 18 2025
.KEY MESSAGES...
- A powerful storm system will bring strong winds, accumulating
snow, and a possible flash freeze leading to potential travel
impacts mid afternoon through the evening hours today.
- Much colder and breezy conditions continue Wednesday with a
few snow showers and lingering blowing snow issues possible.
- A windy period is expected from Thursday through Monday, with
mostly dry weather on tap for most days and the best chance
for precipitation on Saturday.
&&
.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 239 PM MDT Tue Mar 18 2025
Precipitation has begun to move into the CWA early this afternoon.
Current observations show light snow falling in Carbon County with
clouds increasing across the area. Precipitation will continue
to increase in coverage later this afternoon as the upper-level
trough pushes further into the CWA. Surface analysis indicates
a cold front already moved through the area earlier this
morning, and as a result, temperatures are a bit cooler than
forecast across the eastern half of the CWA. Given the cooler
surface temperatures, rain could quickly transition to snow for
areas east of the Laramie Range. Despite the surface cold front
being through most of the area, models indicate the front aloft
will not move through until later this afternoon. This frontal
passage raises concerns for potential snow squalls given strong
mid-level frontogenesis, rather impressive instability, and
strong winds behind the front. Cannot rule out a flash freeze
either as temperatures above freezing will exist ahead of the
front. Also would not be surprised if some areas along the
Interstate 80 corridor hear a rumble of thunder given surface
CAPE values up to 500 J/kg.
Behind the front, precipitation will transition from showery to more
stratiform this evening. Strong mid-level frontogenesis will exist
across the Interstate 80 corridor from Cheyenne to Sidney and in the
northern Nebraska panhandle with the frontal passage. Those under
the strong frontogenesis with model soundings showing saturated DGZs
could see impressive precipitation rates this evening. Nearly
colocated with the frontogenesis are negative EPV values, which
could lead to heavy banded snowfall. However, the window for these
ideal conditions looks brief. Favorable frontogenesis will likely be
out of the CWA before midnight tonight, given the progressive nature
of this system. Because this system is fast moving, snowfall amounts
will be on the lower end. Most locations can expect to see 1 to 3
inches, with both the GFS and ECMWF ensembles in agreement with
this. Members also show good certainty with these amounts with very
little spread between members. The NBM and SREF are also generally
on board with these totals. The HRRR remains an outlier with
snowfall totals, showing higher amounts along the Interstate 80
corridor from Cheyenne to Sidney. Given the strong frontogenesis in
this area, as well as northerly upslope flow along the Cheyenne
Ridge, a few locations could see snowfall totals between 4 and 6
inches. Other areas that could see more than 3 inches include the
Pine Ridge, Chadron, Harrison, Lusk and Douglas as these areas could
see a prolonged period of favorable upslope flow, enhancing snowfall
amounts. The high terrain can also expect to see higher snowfall
amounts above 8 inches. Current Winter Weather Advisories look on
track, so no changes were made to these. Did decided to expand the
Winter Weather Advisory to include the Laramie Valley as north to
northwest flow will put Laramie in a favorable position for upslope.
Also added the South Laramie Range and Foothills to an Advisory as
the HRRR shows decent snowfall amounts here. Snow will taper off
late tonight as this system pushes into Nebraska and Kansas.
The other concern with this system are strong winds. High Wind
Warnings are in place for the South Laramie Range and Foothills as
an impressive MSLP gradient sets up here due to strong cyclogenesis
of the surface low in Colorado. As the surface low strengthens
and pushes eastward into Kansas, the MSLP gradient will steepen
across the eastern half of the CWA. The high wind threat will
push into the southern Nebraska panhandle this evening and
overnight. 800 mb winds will max out at 50 to 55 kts. Decided to
hold off on any high wind headlines at this time as the
strongest subsidence does not line up with the strongest winds
aloft. It is also difficult to get strong winds down to the
surface after sundown in the panhandle as little to no mixing is
present. Despite this, strong winds will still be present east
of the Laramie Range with 50 to 55 MPH gusts not out of the
question. Given the strong wind gusts, blowing snow is likely,
which will lead to reductions in visibility this evening and
overnight as strong winds persist into Wednesday morning.
Expect a cool and blustery day across the CWA on Wednesday. Gusty
winds will continue through the day Wednesday with some patchy
blowing snow possible. Temperatures behind this system will be
cooler as 700 mb temperatures sit around -12C. Highs will mainly be
in the 30s in Wyoming with some low 40s possible in the Nebraska
panhandle. Weak instability across the area Wednesday could also
lead to some snow showers developing during the afternoon hours.
However, little to no accumulation is expected with these.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 239 PM MDT Tue Mar 18 2025
The upper level pattern will be a progressive ridge
and shortwave pattern that looks to result in primarily above
average temperatures and slight precipitation chances every couple
of days throughout the long term period Thursday through Wednesday.
Thursday, our upper level ridge gets flatten to a more zonal pattern
as a weak shortwave moves across the Rocky mountains by the
afternoon the shortwave is expected to move over Southeast Wyoming
and through the Nebraska panhandle by the evening into the overnight
hours. However, our forecast area will be switching from a westerly
flow to a more northwesterly flow still slightly favoring
downsloping for the areas east of I-25. So most of the light
precipitation is expected to fall over the southern mountain ranges.
By Friday a transient ridge moves over our area to give us
temperatures into the 50`s and 60`s before another weak shortwave
moves through on Saturday. Just to note there are disagreements in
how amplified these ridges are between the global models in the long
term period. These ridge differences come from the timing and track
of the parent low pressure system that moves across the Canadian
Providences this weekend. Sunday looks to be the best shot for some
light precipitation as that low pressure system in Canada dives into
the Northern Plains. This forces a slightly stronger trough with a
Northerly flow to overcome our previous downsloping. By Monday, a
Highly amplified ridge moves over us to start off the work week dry
and warm.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 608 PM MDT Tue Mar 18 2025
MVFR to IFR conditions expected over the next 6 hours as light
to moderate snow moves through at CYS, RWL and the NE panhandle.
VIS below 1 mile at times and CIG below 1kft will be likely
before conditions improve after 6z.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Weather Advisory until 6 AM MDT Wednesday for
WYZ101>111-113-115>119.
Winter Storm Warning until 6 AM MDT Wednesday for WYZ112-114.
High Wind Warning until midnight MDT tonight for WYZ116-117.
NE...Winter Weather Advisory until 6 AM MDT Wednesday for NEZ002-
020-054-055-095.
&&
$$
SHORT TERM...SF
LONG TERM...MM
AVIATION...MAC
Area Forecast Discussion...UPDATED
National Weather Service Quad Cities IA IL
935 PM CDT Tue Mar 18 2025
.KEY MESSAGES...
- Showers with scattered storms expected in at least eastern
Iowa north of I-80 in the 5-11 A.M. period; some may bring
small to possibly marginally severe hail
- Scattered storms are expected on Wednesday, with a Slight Risk
(level 2/5) of severe storms east of the Mississippi and a Marginal
Risk (level 1/5) west of the river
- Very windy conditions will be seen on Wednesday, especially in
the afternoon, and a Wind Advisory has been issued for some of the
area with an extension in time possible and expansion in area possible
- Rain becomes snow starting early Wednesday evening and
shifting east; Winter headlines due to possible very low
visibility may be needed
&&
.UPDATE...
Issued at 930 PM CDT Tue Mar 18 2025
Tomorrow`s weather-maker for our area -- yet another strong
closed low trough and deep surface low -- is organizing in the
western Plains this evening. A low-level jet of 35-50 kt is seen
on profilers across eastern Kansas and Missouri. While regional
00Z soundings all the way back to KS indicated considerable dry
air in and above this zone, guidance is consistent with the
increasing warm air advection (WAA) aloft that moistening will
occur for convective initiation in the 4-7 AM period. Given
steep lapse rates aloft, MUCAPE values are forecast to climb to
300-800 J/kg by the pre-dawn hours. This setup within the
diffluence aloft would support the arcs of cells shown by the
HRRR and other high-resolution models lifting northeast over
especially eastern Iowa. This should continue in that baroclinic
leaf through at least mid-morning. Wet-bulb zero levels are low
(~8 kft), so would not take much for some sustained elevated
cells to have hail, and a few could reach that quarter size.
Otherwise this evening, we did extend the Wind Advisory on
Wednesday for the west and south into Wednesday evening as that
period of cold air advection (CAA) looks particularly windy. It
is still very possible that a winter headline of some form is
needed with the snow concurrent to those strongest winds
Wednesday evening, and likely some form of headline will be
needed east to the Mississippi River too given the forecast.
Also in the far south, we collaboratively issued a Red Flag
Warning for the far southern CWA where the driest part of the
warm sector moves over for a several hour period Wednesday
afternoon. Fuel moisture levels in recent afternoons have been
very low (under 7 percent), and with these recent deep lows, the
fire weather conditions have often ended up being on the tail
end of model solutions. So with southern neighbors, we ended up
hoisting that headline.
&&
.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 316 PM CDT Tue Mar 18 2025
Through midnight, dry and unseasonably warm conditions will be seen
across the area.
Between midnight and sunrise Wednesday, elevated convection will
develop north of I-80. While the probability of a severe storm is
very low (less than 15 percent), the stronger storms may
produce some small hail.
Wednesday will be interesting.
The main surface low will move across the area. Although it will be
windy, the passage of the low should help keep winds down.
Further away from the low, winds may become a problem, especially
after the low passes. As a result, wind advisories have been issued
for mainly Wednesday afternoon for the far south and for areas
along/west of I-380/U.S. 218.
The severe risk Wednesday is conditional; that is it is dependent
upon the amount of heating and moisture available. Right now
data suggests there will be a period of mostly sunny skies from
mid-morning through much of the afternoon for areas south of I-
80 and along/east of the Mississippi. This is the area that is
favored if severe storms would develop.
Digging deeper into the models, the window for any severe looks to
be narrow; around 3-4 hours given the forward speed of storms. An
estimate on this window for potential severe looks to be 2 to 5 PM.
Late Wednesday afternoon and continuing into Wednesday night, strong
cold advection on the back side of the storm system will drop
temperatures allowing the rain to quickly turn to snow from west
to east. There will be several hours where snowfall rates and
the wind will reduce visibilities considerably, especially in
open and rural areas. The snow will quickly end from west to
east after midnight.
There is a concern Wednesday night that the snow potential may over
perform on amounts, similar to last weekend. If that does occur,
winter headlines may be needed for the area.
Right now snow amounts of 1 to 2 inches are possible on grassy and
elevated surfaces. However, I would not be surprised if a band
of 2 to 4 inches develops somewhere over the area.
One positive on the snow Wednesday night is that pavement
temperatures will have soaked up a considerable amount of heat over
the previous 48 hours. Thus it will take until late Wednesday night
before pavement temperatures drop close to freezing. As a
result roads will probably remain wet for most of Wednesday
night. However, if a heavier band of snow does develop (it is
anticipated somewhere), slick spots on roads are possible in the
heavier snow band.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 252 AM CDT Tue Mar 18 2025
Thursday and Beyond...
Much of the precipitation should move out of the area by sunrise on
Thursday, leaving us with a cool and damp start to the day. Then,
weak ridging builds over the region Thursday, behind the potent low.
This will result in calmer winds than Wednesday, along with cooler
temperatures working in. Currently, we are expecting much of the
area to remain in the mid 40s to near 50 in our south, with mostly
clear skies by midday.
Beyond Thursday, we remain active. We are currently watching the
potential for two quick hitting systems, one to hit late on Friday,
with another to impact the area late on Sunday and into the night.
Temperatures will be well above freezing for the whole event on
Friday, keeping the precipitation type as rain. Sunday`s system will
largely fall as rain, with cool air moving in on the backside, which
may allow for a transition to light snow. Both of these events look
to bring low QPF and seem to be non-impactful at this time. We will
continue to monitor and update accordingly as more guidance
continues to come in. Otherwise, it will be a gloomy weekend with
clouds and passing systems, aside from Saturday looking to be the
nicest day of this stretch. Temperatures will remain in the upper
40s to mid 50s, with seasonal breeziness.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 650 PM CDT Tue Mar 18 2025
our
Multiple concerns with aviation due to another strong weather
system passing over the region on Wednesday. Ahead of this,
marginal low-level wind shear may be seen overhead overnight.
As the weather system approaches from the pre-dawn hours
through the rest of Wednesday morning, it is likely that arcs of
showers and some thunderstorms develop across eastern Iowa and
track northeast. CID and DBQ are most favorable to experience
these, and some of these storms could even contain small hail.
our
During the early afternoon, the center of the weather system
will be passing directly over the area. This results in a stiff
northeast wind at CID and DBQ with MVFR to potentially IFR
clouds. MLI is much lower confidence in specific attributes to
their TAF due to the system center passing directly overhead.
Scattered showers and storms are likely to re-develop in the
afternoon, although low confidence where these originate and
how quickly. These too also could be strong.
Late in the day Wednesday into the evening, winds will markedly
increase from the due north, with 40+ kt becoming likely at at
least CID. Rain will become more widespread with a changeover
to a wet snow during the evening.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Wind Advisory from 1 PM to 10 PM CDT Wednesday for IAZ040-041-
051-052-063-064-076-077-087-088-098.
Wind Advisory from 9 AM to 10 PM CDT Wednesday for IAZ099.
IL...Wind Advisory from 9 AM to 10 PM CDT Wednesday for ILZ034-035.
Red Flag Warning from 1 PM to 5 PM CDT Wednesday for ILZ034-
035.
MO...Wind Advisory from 9 AM to 10 PM CDT Wednesday for MOZ009-010.
Red Flag Warning from 11 AM to 5 PM CDT Wednesday for MOZ009-
010.
&&
$$
UPDATE...Friedlein
SHORT TERM...08
LONG TERM...Gunkel
AVIATION...Friedlein
Area Forecast Discussion
National Weather Service Goodland KS
955 PM MDT Tue Mar 18 2025
.KEY MESSAGES...
- A High Wind Warning is in effect for the entire area Tuesday
evening through Wednesday afternoon with northerly winds
gusting generally up to 65 mph, but occasionally up to 70 mph
especially across eastern Colorado.
- A Blizzard Warning is in effect for all counties except
Cheyenne (CO), Greeley, Wichita, and Wallace where an advisory
is in place for blowing snow. Blizzard conditions are forecast
to begin around 9pm MT and continue through the late morning
hours with a gradual west to east decline in worst conditions.
&&
.UPDATE...
Issued at 810 PM MDT Tue Mar 18 2025
Critical fire weather conditions are not longer expected.
Therefore, the Red Flag Warning has been allowed to expire.
Rest of forecast generally on track, no significant changes made
at the moment.
&&
.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 219 PM MDT Tue Mar 18 2025
The surface low has set up a little further south than
anticipated today which is limiting winds mainly along and
north of Highway 36 which is impacting the northeast portion of
the of the current Red Flag Warning but overall the Red Flag
Warning is performing as anticipated. Am not planning on ending
any part of the Red Flag at this time as as the prefrontal
moves north a little bit as the low deepens some, so do still
continue to think there will be multiple hours of critical fire
weather conditions for the northeast county along with the
anticipated wind shift making it more of a impact based red
flag warning. The blowing dust threat has also been panning out
as well thus far with a more pronounced plume originating
around the Kiowa/Crowley county area and advecting into the
Cheyenne, Wallace, Logan, and Greeley counties. Other than a few
reports around 0.5 miles visibilities that at least have been
reported have been around the one mile range. Do think the
reasoning for not any more significant visibility reductions is
due to the fact that the 2- 2.5km lapse rates are higher which
is allowing for the dust to diffuse more into the atmosphere.
Localized brownout conditions are still possible especially
near open fields and other dust source regions.
Now to the cold front, timing on that remains on track with a
passage through the area of around 6p-8pm MT. Am continuing to watch
very closely for any potential surges in speed as well which would
increase the haboob potential. My confidence in this still
remains around 10-20% chance in occurrence. For the wind behind
the front wind gusts of 60-70 mph are currently forecast due to
very strong pressure rises of 11-16mb over three hours which
should be remain enough to mix down high wind warning winds. The
GFS continues to be the most aggressive with the wind field
with 60+ knot winds just above 785mb to even 50 knot winds right
at the surface so overall expectations remain the same. The
HRRR and other Hi-Res guidance has consistently been showing a
swath of 70+ knot wind gusts across western portions of Kit
Carson and Cheyenne counties, which may not be impossible
especially if the wind fields are right as GFS soundings via
BUFKIT show 70 knot winds near Limon so may need to continue to
keep an eye on that potential as the evening goes on.
I did get enough confidence to upgrade Yuma and Kit Carson
county to a blizzard warning. Based the current forecast cold
air advection due think that the rain should change over the
snow to lead to blizzard conditions as the winds will be well
exceeding the 35 mph criteria. The main question is the amounts
due to the potential precipitation changeover dilemma and
exactly where does that set up at. The tipping point for me was
a very strong signal on the snow band tracker via the HRRR and
HREF output of that tool and the Aberdeen blowing snow model
showing 80+ percent probabilities given the current forecast
parameters. The other part of the decision was due to a
noticeable western trend of the shift of tails on recent runs
of the EFI. Otherwise the blowing snow forecast remains on
track. The overall most treacherous part of the period will be
mid evening across the west and gradually moving east across the
area overnight to eastern portions of the for the morning
hours. This may end up being the most impactful part of the
event due to the overlapping of the blizzard conditions
impacting the morning commute.
The conditions are forecast to gradually improve west to east
through the morning hours before being fully out of the area by the
early morning. Winds however will still be the story on Wednesday as
near 60 mph wind gusts will remain the theme through the morning
hours and perhaps a bit longer than that across the east, so may
need to keep an eye on a potential extension of the High Wind
Warning for eastern counties. Both the RAP and the GFS has
favorable lapse rates for blowing dust along and south of
Highway 40 but west of Highway 25 during the afternoon hours
Wednesday. I did go ahead and introduce some patchy dust wording
into the forecast to account for this but may be more of a
conditional threat due to how much precipitation does occur
tonight and if cloud cover remains thick enough that lapse rates
don`t destabilize as much as what guidance currently shows.&&
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 219 PM MDT Tue Mar 18 2025
Thursday is forecast to see mid level ridging developing with a
surface trough which is forecast to bring additional gusty winds to
the region allowing for another day of critical fire weather
concerns as winds gust around 30-35 mph. This may be mitigated
however if there is some remaining snow pack based on how
tonight goes.
Friday, another trough and associated surface low are forecast to
move through the area. This should increase winds and bring another
dry slot through the area, allowing for continued critical fire
weather conditions. There is a chance for wind gusts above 55 mph in
western portions of the area, though the low doesn`t look like it
will deepen enough looking at ensemble members. For now the chance
is less than 20%, but keep an eye out for updates. There is a small
chance for precipitation, but it is currently unlikely that the low
would wrap enough moisture for meaningful precipitation.
This weekend looks to continue the active pattern with more small
ridges and troughs. Critical fire weather conditions remain likely
with the systems keeping winds elevated and a forecast lack of
meaningful moisture return into the area. That is not saying that
there aren`t chance for storms and maybe some snow, just that it
currently isn`t the favored solution.
Temperatures currently for this time period will see highs
rebounding into the 60s from the brief cool down on Wednesday.
At this time Saturday looks to be the warmest with the potential
for 70s before another brief cool down with a late weekend
system.
&&
.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 955 PM MDT Tue Mar 18 2025
KGLD...sub VFR conditions are expected from taf issuance through
about 13z due to snow and blowing snow with northerly winds
gusting up to around 50kts or so. From 14z-00z, northwest winds
gusting up to 55kts in the morning very slowly decrease through
the day with gusts around 30kts near 00z. After 01z, winds will
be under 10kts.
KMCK...sub VFR conditions are expected from taf issuance through
about 13z with northerly winds gusting up to 50kts. A rain/snow
mix at taf issuance should quickly change over to snow with
blowing snow as well. After 14z, VFR conditions are expected.
Northwest winds gusting up to 50kts at 14z very slowly decrease
through the day with gusts around 30kts by 23z. After 02z, winds
are expected to be around 10kts from the northwest.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...High Wind Warning until noon MDT /1 PM CDT/ Wednesday for
KSZ001>004-013>016-027>029-041-042.
Blizzard Warning until noon MDT /1 PM CDT/ Wednesday for
KSZ001>004-013>016-028-029.
Winter Weather Advisory until noon MDT /1 PM CDT/ Wednesday
for KSZ027-041-042.
CO...High Wind Warning until noon MDT Wednesday for COZ090>092.
Blizzard Warning until noon MDT Wednesday for COZ090-091.
Winter Weather Advisory until noon MDT Wednesday for COZ092.
NE...High Wind Warning until noon MDT /1 PM CDT/ Wednesday for
NEZ079>081.
Blizzard Warning until noon MDT /1 PM CDT/ Wednesday for
NEZ079>081.
&&
$$
UPDATE...99
SHORT TERM...Trigg
LONG TERM...Trigg/KAK
AVIATION...99
Area Forecast Discussion
National Weather Service Grand Rapids MI
946 PM EDT Tue Mar 18 2025
.KEY MESSAGES...
- Showers/thunderstorms possible Wednesday into Wednesday night
- Rain changing to snow Wednesday night into Thursday morning
- Becoming Windy Wednesday night
- More systems expected this weekend and early next week
&&
.UPDATE...
Issued at 946 PM EDT Tue Mar 18 2025
Temperatures are running warmer than originally forecast,
therefore bumped up the low as warm air advection is expected to
continue overnight.
&&
.DISCUSSION...
Issued at 349 PM EDT Tue Mar 18 2025
- Showers/thunderstorms possible Wednesday into Wednesday night
First impact weather in the 7 day forecast is the chance for
thunderstorms tomorrow evening, a few of which could be strong to
severe. A deep spring time low organizing in the lee of the
Rockies this evening will make a run at the Great Lakes tonight
and on Wednesday. Moisture will be pulled northward ahead of the
low on strong southerly winds. Surface dew points will surge to
near 50F, while 850mb rise to around +8C. This is enough moisture
to fuel thunderstorms especially given the strength of the system.
That said, the HREF 4hr max reflectivity swaths paint a picture of
embedded storms within a larger area of showers. The moisture
could be better, which results in scattered storms. Multiple
model outputs including the HREF and HRRR indicate that MUCAPE
may surge to around 1,000 j/kg in the far southern CWA Wednesday
evening. Shear will be high given a LLJ of 50 knots and backed
surface flow. 0-1 SRH values exceed 300 m2/s2 for a short window
tomorrow evening. Bottom line, there is a period of time between
roughly 700pm and midnight where a few storms may acquire rotation
and have the possibility of becoming severe. Best chances for
anything close to severe will likely be near Van Buren and
Kalamazoo Counties around 1000pm Wednesday evening. Scattered
showers with locally heavy rain and small hail are the most likely
scenario. The strongest of storms if conditions come together
right will be capable of hail to near severe levels and wind
gusts to around 60 mph.
- Rain changing to snow Wednesday night into Thursday morning
The low will be moving quickly off to the northeast Wednesday
night and therefore colder air sweeps into the area on the back
side of the low. Rain will change to snow Wednesday night from
west to east. There will be a deformation zone of snow that will
slide northeast through the area over West Central Lower Michigan.
The best chance of seeing accumulating snow will be for areas
north of Muskegon up towards Hart and Ludington and points east of
there from Baldwin and Big Rapids to Clare. We have an inch or so
of snow in the forecast at this point, but would not be surprised
to see a swath of 1-3 inches move through the area. Elsewhere any
snow will likely be in the trace to a dusting variety before the
precipitation ends Thursday morning.
- Becoming Windy Wednesday night
Winds will likely gusts to around 40 mph inland away from Lake
Michigan Wednesday night which is below advisory levels. Higher
winds to 50 mph are possible along the lakeshore, especially up
near Big and Little Sable Points. A Wind Advisory is not out of
the realm of possibilities given current model data.
- More systems expected this weekend and early next week
Two more systems are in the pipeline to affect the area Friday
night into Saturday and again Sunday into Monday. The end of the
week system is a clipper system that does not have the moisture
that the mid week low will have. We have chance pops in the
forecast at this point for that system for rain showers.
The weekend and early next week time frame will feature a
stronger low moving through which will be followed by lingering
upper troughing. So, the Sunday through Tuesday period will be an
unsettled weather time frame with chances for precipitation each
forecast period. A mix of rain and snow is in the forecast during
this time frame spring daytime heating will battle cold
temperatures aloft.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 752 PM EDT Tue Mar 18 2025
VFR expected through this evening. 40 TO 50 knots LLWS from 2,000
feet is beginning to develop and will intensify as the evening
continues. It will be strongest around 03Z through the southern
half of Lower Michigan, persisting until about 10Z. Late tonight
and early Wed morning, ceilings will lower the farther north you
are in Lower Michigan. MVFR will become likely near and north of
FFX- RQB- MOP. Toward mid-day Wed, MVFR ceilings will develop
through southern Michigan and continue to lower as showers will
overspread from the NW to the SE. MVFR vsbys will be possible
after 22Z tomorrow with a chance of storms after 00Z Thursday.
&&
.MARINE...
Issued at 946 PM EDT Tue Mar 18 2025
A Gale Warning is now in effect starting Wednesday night and
continuing into Thursday. Strong north- northwest winds are
expected on the backside of the departing low. BUFKIT overviews
for points along the lakeshore and at mid lake suggest a strong
gale to 45 knots. The case could be made for a Storm Warning given
a pressure gradient bookended by a 990`s mb low in the Great
Lakes and a 1035 mb high in the Rockies. We will have to monitor
trends on the 50 knot winds in the mixed layer. If they persist in
the forecast going forward an upgrade may be necessary. At this
point confident in high end gales. WaveWatch3 is showing 12-16
foot waves in the long north fetch, especially off shore. Given
the lower than average lake levels and an along shore flow not
expecting issues with significant erosion or lakeshore flooding.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Gale Warning from 5 AM to 2 PM EDT Thursday for LMZ844>846.
Gale Warning from 11 PM Wednesday to 2 PM EDT Thursday for
LMZ847>849.
&&
$$
UPDATE...RAH
DISCUSSION...Duke
AVIATION...CAS/Ceru
MARINE...Duke/RAH
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1028 PM CDT Tue Mar 18 2025
.KEY MESSAGES...
- A storm system will move across northern Illinois bringing
rain, high winds, and possibly strong thunderstorms to the
area Wednesday.
- Chances for slushy snow to mix in Wednesday night into
Thursday morning
- Seasonal conditions this weekend into early next week with
several chances for precipitation, highest on Sunday
- Seasonably cool temperatures early next week to start
astronomical Spring.
&&
.UPDATE...
Issued at 1028 PM CDT Tue Mar 18 2025
Main Forecast Changes This Evening:
- Cooler temperatures and northeasterly winds north of a sagging
front tonight into Wednesday morning
- Wind Advisory for Livingston, Ford, Iroquois, and Benton
Counties 10am-7pm CDT Wednesday
- Farther south low pressure track on Wednesday resulting in a
sharp temperature gradient roughly near/north of I-90 corridor
- Afternoon severe threat will in all likelihood be confined to
primarily near/south of afternoon warm front position, which
is uncertain, but likely south of IL/WI stateline counties
A very complex and challenging forecast period is in store
through Thursday morning. First order of business was to adjust
for the previously stationary front sagging farther south into
northern Illinois this evening, resulting in cooler temperatures
and north-northeasterly winds. The farther south frontal
position will play a role in Wednesday`s key forecast elements
(winds, temps, convective trends and severe threat). East-
northeasterly winds north of the front will be slower to return
to southerly with northward extent, and as noted above, locales
particularly near the IL/WI stateline are unlikely to see
southerly winds and the expected mild (60s) temps. In fact,
can`t rule out some fog near the lake in far northeast Illinois.
The exact track of the strong upper 980s mb surface low will
dictate the precise location of the warm front in the afternoon
as an arcing dryline approaches.
An area of warm advection driven showers and perhaps some
isolated thunderstorms (due to steep mid-level lapse rates)
should develop over the northeastern half or so of the area in
the morning and then slide east through midday/early afternoon.
South of these showers (well south of the warm front), a very
strong low-level jet with 40+ kt flow down to around 1kft AGL or
less, and temps jumping into the 60s supporting mixing into the
base of the LLJ should result in 45-50 mph gusts across the
southern tier of the CWA toward midday and through the afternoon
(aside from convective influences). These stronger advisory
criteria (45 mph) gusts may spread to near the Kankakee River
Valley or so, which the midnight shift will assess, with respect
to possibly expanding the Wind Advisory northward.
A plume of fairly shallow 50s dew points, possibly as high as
mid-upper 50s, will be drawn northward by the strong southerly
flow in the warm sector, up to the warm front terminus. The main
period of interest is in the mid afternoon through early evening
as the aforementioned arcing dryline lifts northeast and
increases convergence in the weakly to moderately unstable warm
sector. While instability will be fairly minimal (generally less
than 500-1000 J/kg), cold temps aloft and strong low-level
turning/veering are a supportive pattern for the development of
low-topped mini supercells. If the more aggressive dew point
guidance verifies and the moisture is sufficiently deep, could
see 100+ J/kg of 0-3km CAPE.
This is important because there could be a corridor within the
CWA where low-level hodographs are favorable for more than the
current 2% tornado probs in the day 2 SPC outlook. If the
meridional flow aloft leads to more of a messy storm mode, then
small linear clusters could result in a wind damage threat given
the very strong winds aloft. Finally, low-topped mini
supercells aren`t typically associated with a significant hail
threat. The cold temps aloft and low wet bulb zero heights could
compensate somewhat for isolated marginally severe (~1"
diameter) hail in the most intense cores. Needless to say,
mesoscale trends will need to be closely monitored for the
~2pm-8pm CDT severe threat window.
Finally, given the farther south low pressure path, winds
should shift to strong northerly a bit quicker Wednesday
evening, with rapidly falling temperatures. A developing
backside deformation precip axis should produce a short window
of wind whipped accumulating wet snow, with the exact favored
corridor still uncertain. We may even need to consider another
wind advisory for the north-northwesterly winds Wednesday
night.
Castro
&&
.DISCUSSION...
Issued at 330 PM CDT Tue Mar 18 2025
Through Thursday:
Winds are starting to increase this afternoon as better daytime
mixing is occurring. A 30-40 knot low level jet is expected to
increase this afternoon, particularly south of I-80. Southerly winds
are expected to gust between 25 to 30 mph. Winds will slowly
diminish overnight, through gusts around 20 mph are possible
through the night.
Currently, there is an upper level trough passing over the
Rocky Mountains. Recent mesoanalysis shows a center of low
pressure is already developing over the Colorado front range as
surface cyclogenesis is underway. This low will move east
through the overnight and Wednesday bringing showers, stronger
storms and potentially snow (as it exits) to the area on
Wednesday into Thursday morning.
The upper level trough is expected to have a 100+ knot jet
embedded in it, with the left exit region over northern Illinois
late Wednesday morning providing additional synoptic lift.
Steep lapse rates will slowly sweep over the area through the
day. Showers and potentially some thunder are possible in the
morning and early afternoon, mainly in far northern Illinois.
Southerly winds will increase through the day on Wednesday.
While the forecasted gusts were bumped up, most of the area
should remain in sub-advisory criteria (below 45 mph gusts) for
any significant length of time. If winds over perform, a wind
advisory may be needed, especially for areas south of I-80.
There are no major changes from the previous forecast with the
severe threat in the afternoon. There is the potential for a
brief break in the showers between the initial morning boundary
and the dry line moving through in the afternoon. However, that
dry line is expected to be the main triggering mechanism for
storms to fire in the afternoon. With good synoptic forcing,
steep mid level lapse rates and decent MUCAPE, strong scattered
thunderstorms are possible tomorrow afternoon. The main limiting
factor is the amount of moisture available. Even leaning on the
HRRR for creating the forecast only netted dew points in the
low 50s. Storm mode will be mini supercells. The main concern
will be damaging wind, but hail is possible as equilibrium
levels will remain colder than minus 20C for a brief time. Model
hodographs depict strong low level shear, so a brief spin-up
tornado is possible, but LCLs on model soundings look a little
higher which is a limiting factor. All this being said, the
forecast area remains in the SPCs slight risk (level 2 out of 5)
for severe weather.
As the low moves east, winds will flip over to the northwest
ushering in cold air advection. Snow is expected to mix in with
the rain through the overnight and into Thursday morning. With
lower snow ratios, wet slushy accums are possible creating
slippery travel on Thursday morning. While the risk for slushy
accums is possible area wide, higher confidence is closer to
the Rockford Metro area and for areas along the Wisconsin
border. The northwest winds will gust around 40 mph, There is a
chance a wind advisory may be needed during this window as
well, however current models are showing the system weakening
as it moves through the area.
There is lower confidence on the exact timing the system exits
on Thursday morning. While there may be some lingering snow and
showers, it should dissipate in the afternoon. Otherwise drier
conditions are expected with temperatures returning to seasonal
normal values.
DK
Thursday Night through Tuesday:
The reprieve from the active storm track will be short lived on
Friday, but most areas will make it through the daylight hours
precipitation free. Transitory upper level ridging will pass
overhead Thursday night before it shifts eastward quickly Friday
morning. Warm advection ahead of Pacific origin upper trough
will hopefully keep low temperatures in check Thursday night to
prevent too much frost development, but will also allow
temperatures to recover back to the mid to upper 50s. It again
appears like Friday will be fairly breezy again. With the
increase in moisture and cloud cover, that should keep RH values
from falling too much during the day during peak mixing to
limit the fire weather threat, though wind gusts to 35 mph are
certainly plausible, even up to 40 mph south of I-80. We could
see some isolated showers during the afternoon Friday, most
favored west along the I-39 corridor, more so across NE IA and
NW IL.
The neutrally tilted trough will move through the area late
Friday and Friday night and send a weak cold front with it.
PWATs and low level moisture only modestly increase, scattered
showers with decent coverage (though not everywhere) is the
appropriate forecast at this distance.
This system will quickly exit east Saturday morning and no
precipitation is expected during the day. Temperatures on
Saturday will only modestly recover, as highs look to be
generally in the 40s around the area, maybe tagging 50 in the
west. Onshore winds will develop sometime during the day or
early evening which will also keep nearshore areas cooler.
Another more interesting northern stream Pacific origin trough
will pass through the Great Lakes region on Sunday. This system
packs a bit more punch than Friday night` system, and will
likely have a bit better moisture feed and thus precipitation
chances are correspondingly in the likely category. There are
still some timing discrepancies to resolve. Confidence is high
that temperatures Sunday night into early Monday will support a
mix or even a changeover to snow (across north central IL),
though it is not clear how much of the storm`s deformation axis
will affect northern IL.
Northwest flow will remain in place behind this system early
next week, and this will keep temperatures cooler than normal.
Subtle weak waves may bring low end precipitation chances at
times.
KMD
&&
.AVIATION /00Z TAFS THROUGH 06Z THURSDAY/...
Issued at 627 PM CDT Tue Mar 18 2025
Aviation Forecast Concerns:
- Lake-enhanced cold front expected to sag across the terminals
this evening, producing a wind shift to the northeast. Front
then lifts back north as a warm front with gusty south winds
early Wednesday afternoon.
- Period of LLWS possible for Chicago metro terminals late this
evening.
- MVFR conditions develop Wednesday morning with a period of
SHRA.
- Period of scattered strong TSRA Wednesday afternoon.
- Winds become gusty from the north at 30+ kts Wednesday
evening.
Complex forecast through the next 30 hours, as a significant low
pressure system moves across the area through Wednesday. In the
near term, gusty south winds will ease with sunset and are
expected to allow a cold front to sag across the terminals
(except perhaps KGYY) mid-late evening. Exact timing at ORD/MDW
is a little uncertain, though it appears by mid-late evening a
wind shift to the northeast at both airfields is likely. During
the late evening/early overnight hours, a southwesterly 40-50 kt
low level jet may support a brief period of LLWS conditions.
Latest high-res model forecasts suggest the front will then
remain south of the terminals through midday Wednesday, before
lifting back north ahead of the approaching low pressure center.
Winds would then shift south and become gusty Wednesday
afternoon (lowest confidence at KRFD, depending on the exact
surface low track), before eventually shifting north later
Wednesday evening as the low center passes east of the area.
As the low approaches Wednesday morning, and area of showers is
expected to develop across WI and northern IL, which will likely
result in the development of MVFR ceilings and occasional MVFR
vis. Scattered showers and MVFR conditions will persist through
midday, before improving to VFR as the warm front lifts north
of the terminals early in the afternoon. Within the warm sector,
a modestly unstable air mass will likely support scattered
thunderstorms ahead of a surface trough by mid-late afternoon,
and some of these could be strong to severe with gusty winds.
Some guidance is a little slower with the timing of these
storms, but given the larger scale forcing and diurnal timing,
the 20-24Z time frame appears quite reasonable at this time.
As the surface low moves east of the terminals Wednesday
evening, winds will shift to the north, and become quite strong
with gusts above 30 kts developing. A period of rain showers is
also expected, which will likely change over to wet snow later
Wednesday night, just beyond the end of this forecast period.
MVFR and potentially IFR conditions are possible within this
area of precipitation.
Ratzer
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Wind Advisory from 10 AM to 7 PM CDT Wednesday for ILZ032-
ILZ033-ILZ039.
IN...Wind Advisory from 11 AM to 8 PM EDT Wednesday for INZ019.
LM...Gale Warning from 9 PM Wednesday to 1 PM CDT Thursday for
Winthrop Harbor to Wilmette Harbor IL.
Gale Warning from 3 PM Wednesday to 1 PM CDT Thursday for
Wilmette Harbor IL to Michigan City IN.
Small Craft Advisory from 10 AM to 3 PM CDT Wednesday for the
IN nearshore waters.
&&
$$
Visit us at weather.gov/chicago
Area Forecast Discussion
National Weather Service Marquette MI
747 PM EDT Tue Mar 18 2025
.KEY MESSAGES...
-A late-season winter storm will bring heavy snow and strong
winds to portions of Upper Michigan Wednesday and Wednesday
night with the worst conditions starting in the late
afternoon/evening hours. The combination of high winds and
heavy, wet snow will result in difficult travel conditions and
potential power outages.
-Light snow Wednesday morning will become moderate to heavy
into the afternoon and evening, with rates of 1-2"/hr expected
in the heaviest bands.
-Snow will become more fluffy in the evening, leading to
possible whiteout conditions, especially near the Lake Superior
shorelines. Travel will be very difficult.
&&
.UPDATE...
Issued at 747 PM EDT Tue Mar 18 2025
Weak radar returns persist across the northern UP this evening, co-
located with a swath of higher, cooler cloud tops evident on IR
satellite imagery. Little has been able to reach the ground, but
still will not rule out some light snow or rain/snow mix with weak
isentropic lift ahead of the approaching wintry system. Water vapor,
meanwhile, is showing dry midlevel air nosing into the southern half
of the UP. This area has seen some erosion in cloud cover, but the
northward extent of clearing is in question given the proximity to
our weak boundary and the onshore/upsloping flow off of Superior.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 127 PM EDT Tue Mar 18 2025
Early afternoon water vapor and 500 mb RAP analysis shows mid/upper
level moisture increasing into the Upper Great Lakes amid confluent
flow. Deep southern stream trough that will be responsible for our
next weather system is currently pushing through the Desert
Southwest, while a northern stream shortwave is crossing the
Canadian Rockies. At the surface, low pressure is emerging onto the
central Plains, while a ridge of high pressure is located from
around Lake Nipigon to James Bay.
As the low continues to eject off of the Plains, weak bands of
isentropic lift will set up in the vicinity of the UP. However,
forcing is expected to be weak through tonight, and drier air
draining from the high to the north should keep any precipitation to
nuisance levels at most. This is currently manifest by virga on area
radars. The threat of any freezing rain overnight appears to have
lessened relative to prior forecasts, but a few patches of freezing
rain or freezing drizzle can`t be ruled out around interior portions
of Alger/Marquette and back toward Iron/Dickinson. This does not
appear to warrant any advisories but will monitor for the need of
any short-fused SPS. With saturation aloft, seeder-feeder processes
may result in p-type being rain or snow instead of freezing rain.
Lows tonight mainly in the upper 20s to low 30s.
&&
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
Issued at 400 PM EDT Tue Mar 18 2025
The anticipated late season winter storm begins to take shape
tomorrow as a deep trough swings out of the Rockies, reflecting a
~987 surface low pressure somewhere along the IA/MO border by 15z
Wednesday morning. The low lifts northeast reaching southern Lake
Michigan by the evening, increasing PoPs as the f-gen circulation
shifts northward. Though not as pronounced as previous model
guidance suggested, a NE-SW thermal gradient will start off
precipitation as rain or a wintry mix across the south and east
closer to Lake Michigan before transitioning to snow as colder air
wraps into the area.
Global models have trended towards a flatter upper level wave
interacting with the opening Colorado low, leading to a slightly
weaker surface low elongating into southern Michigan early Thursday.
This places the heaviest QPF axis a bit south and east than
previously forecast, highlighted well by the 12z CAM guidance, which
decided to take a significant shift southeast, further decreasing
confidence on snowfall amounts over the west and Keweenaw. At the
same time, this shunts the encroaching midlevel warm nose further
south east, decreasing freezing rain accumulation potential. Latest
HREF and NBM probabilities for 0.01" of freezing rain have lessened
to below 30% (basically 0% in the NBM) Wednesday afternoon. As for
snowfall totals, there is still a high amount of uncertainty as model
trends continue their shift south and east. The west and Keweenaw
could only see a few inches, but depending on the overnight guidance
its possible they could remain dry. Elsewhere, a heavy band of snow
is likely across the central UP, and in combination with
upslope/lake enhancement could potentially see upwards of 12-15" by
12z Thursday, though the latest ensemble trends are becoming
unfavorable for this solution.
Interestingly, there is a signal for some CSI (conditional symmetric
instability) release atop the south-central U.P. during the
afternoon and evening hours where CAMs depict negative theta-e lapse
rates and EPV slightly below zero in a saturated layer near the 700-
600mb fgen max. This could provide a slight enhancement to precip
rates and additional dynamical cooling, quickening the transition
from mixed precip to snow. If this occurs after the transition to
snow, a period of heavier >1" snowfall rates is possible. This may
be outlined in the latest 12z HREF run, where probability for >1"
snowfall rates increases >60%.
Impacts are increasingly likely with heavy, wet snow possible
accompanied by gusty winds up to 30-40 mph; there is a 30-60% chance
for wind gusts exceeding 40 mph in the Keweenaw and east half,
particularly near Lake Superior. With the bulk of snow falling as
wet snow, primary impacts are expected to be difficult travel and
potential power outages with gusty winds, however a brief period of
significantly reduced visibilities Wed evening over the west and
overnight into Thursday is possible as snow becomes dry and fluffier.
High pressure building in from the W on Thu dries out lingering lake
enhanced showers over the E by the evening hours with dry weather
likely carrying into Fri. Beyond the midweek system, PoPs increase
late in the day Fri into Sat as a mid level trough dives SE over the
Upper Great Lakes and another trough quickly emanates off the N
Rockies. Additional chances for precip is anticipated early next
week with another trough tracking off the N Rockies.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 747 PM EDT Tue Mar 18 2025
Low stratus continues to lead to MVFR restrictions at IWD and IFR
and SAW this evening, and while restrictions should persist at SAW
tonight, there is a potential for a brief period of improvement at
IWD after midnight. Meanwhile, at CMX, ceilings have lifted to VFR.
There is a 20-30% chance for light snow at the terminals during the
overnight hours as well, and about a 10% chance for freezing drizzle
at SAW 06-12Z, but confidence too low to mention in the TAFs. Strong
low pressure system organizing to our south will bring steadier snow
to SAW starting between 12-15Z Wed, resulting in a return to IFR
vsby, and possibly LIFR after 18Z. IWD/CMX will be more on the
periphery of the snowfall, so PROB30s were used tomorrow morning and
afternoon. CMX may even stay at VFR the rest of the forecast period.
Northeast winds will increase with gusts to 25 kt 12Z Wed onwards.
&&
.MARINE...
Issued at 400 PM EDT Tue Mar 18 2025
Northeast winds across the lake increase to 20-30 kts tonight as a
strong low pressure approaches the Great Lakes. Winds gradually back
north Wednesday afternoon through Wednesday night, increasing up to
gales to 35-40 kts over the eastern two thirds of the lake. The
strongest winds are expected over the east half where there is a 50%
chance for high end gales up to 45 kts, particularly near the
southern shores. Gales likely fall off by Thursday afternoon as
winds back west. 15-25 kt winds back southwest for Thursday night
and Friday. Winds quickly veer northwest Friday evening, increasing
to 20-30 kts through Saturday morning behind a cold front. There is
a 40-60% chance for gales to 35 kts behind this front Friday night
into Saturday with the strongest winds expected along the
international border. Winds likely settle below 20 kts again
Saturday night, remaining 20 kts or less the rest of the weekend.
Otherwise, some light freezing spray is possible late Wednesday
night through Thursday, primarily over the east half of the lake.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Winter Storm Warning from noon EDT /11 AM CDT/ Wednesday to 2
AM EDT /1 AM CDT/ Thursday for MIZ004-010-011.
Winter Storm Warning from 10 AM Wednesday to 5 AM EDT Thursday
for MIZ005-006.
Winter Weather Advisory from 10 AM EDT /9 AM CDT/ Wednesday to
5 AM EDT /4 AM CDT/ Thursday for MIZ007-012>014-085.
Winter Weather Advisory from 10 AM to 10 PM CDT Wednesday for
MIZ009.
Lake Superior...
Gale Warning from 2 PM EDT /1 PM CDT/ Wednesday to 8 AM EDT /7
AM CDT/ Thursday for LSZ240>244-263-264.
Gale Warning from 8 PM Wednesday to 2 PM EDT Thursday for
LSZ245>251-265>267.
Lake Michigan...
Gale Warning from 5 PM Wednesday to 2 PM EDT Thursday for
LMZ221-248-250.
&&
$$
UPDATE...
SHORT TERM...Thompson
LONG TERM...BW
AVIATION...LC
MARINE...BW
Area Forecast Discussion
National Weather Service Springfield MO
642 PM CDT Tue Mar 18 2025
.KEY MESSAGES...
- Elevated to Significant fire danger today with a Red Flag
Warning until 8PM.
- Gusts of 40-50 mph expected today. Wind Advisory for portions
of the area until 8PM. Wind Advisory issued for the whole
area for Wednesday 8AM-8PM for gusts up to 55 mph.
- Light rain showers Wednesday afternoon transitioning to light
snow in the evening and overnight. No snow accumulations.
- Fire weather risk is elevated for Wednesday and Thursday and
significant for Friday.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 211 PM CDT Tue Mar 18 2025
Ridging will continue over us for the rest of the day ahead of a
digging trough over the southwestern US. The pressure gradient will
continue to tighten over the next 48 hours as this low continues to
deepen and push east. Therefore, have issued another Wind Advisory
for tomorrow for 8AM-8PM. Expect sustained winds of 20-30 mph and
wind gusts up to 55 mph as winds will be a bit stronger tomorrow as
that low gets closer. Don`t forget the Wind Advisory and Red Flag
Warning that are in effect through the evening hours today due to
gusty southwesterly winds and low RH values in the 20-30 percent
range. Decided not to go with a High Wind Warning at this time
because the probability of seeing a wind gust greater than 58 mph is
about 10-15 percent and is only over a couple of counties along the
I-49 corridor. So, we can`t rule out a wind gust or two reaching
that criteria in that area, but most wind gusts should stay around
50-55 mph. Either way, be sure to tie down loose objects outside and
use caution when traveling especially along I-49.
Highs today will be sunny and warm in the upper 70s to lower 80s. We
were already in the lower 70s around noon today. Tomorrow will be a
much different story as a cold front pushes through in the
afternoon. Winds will start out from the southwest but then turn
northwesterly once the front goes through. They will remain elevated
behind the front into the overnight hours before diminishing by
early Thursday morning. Wednesday`s high temperatures will likely
occur in the morning when heading out the door. Temperatures around
sunrise will be between 60-70 degrees. Then, by lunchtime, cold air
filters into southeastern Kansas and southern Missouri to drop
temperatures into the 40s with a gusty northwesterly wind. Low
temperatures bottom out in the lower 30s for Wednesday night.
As far as precipitation goes for tomorrow, there is still a signal
for a rain to snow transition. Again, no accumulations are expected
and the best chances for precipitation will occur over central
Missouri (30-70%). The transition could occur as early as 4-5PM for
the southwestern Kansas and far western Missouri counties. The
system will then spread east across the area and will persist
through Wednesday night and end by Thursday morning at sunrise.
&&
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
Issued at 211 PM CDT Tue Mar 18 2025
Thursday:
Could see some elevated fire weather Thursday, but high temps
in the 50s should help inhibit greater concern. MinRH values of
20-30% are expected. Winds will be from the NW at 10-15 mph
gusting to 15-25 mph.
Friday:
Warmer Friday with highs in the 60s. Elevated to significant
fire weather is a concern given minRH values of 20-30% and max
southerly gusts of 30-40 mph.
Next weekend:
Saturday looks like another 20-30% minRH day, but with light
winds. Still plenty of uncertainty with details, but a pair of
shortwaves Saturday night into Sunday (~60%). Still a long way
out with limited confidence, but will monitor for severe
potential given low end probabilities from CSU ML and CIPS
output edging into the area and the SPC outlook just south of
the CWA. Look for highs in the 60s both days.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 640 PM CDT Tue Mar 18 2025
Main aviation concern this TAF period is gusty southerly winds
slowly shifting to westerly by the end of the period. Sustained
winds of 15-25 kts with gusts up to 35-40 kts are possible
(infrequent gusts up to 45 mph). These strong winds will create
a period of southerly LLWS at 50 kts between 03-13Z.
There is low confidence in a brief period of MVFR cigs for SGF
and BBG between 09-11Z. This is based on latest RAP guidance
forecasting a surge of low-level moisture moving into the region
in that timeframe. Confidence in BKN cloud development is
currently too low to include in the TAF.
Confidence is higher for MVFR cigs to move in with a fropa
towards the end of the TAF period. Some drizzle or light showers
are also possible (20-30% chance) with this activity, but left
out of the TAF for now given uncertainties in exact timing and
precip mode.
&&
.FIRE WEATHER...
Issued at 330 AM CDT Mon Mar 17 2025
For specific local forecasts, see our forecast webpages or the
Fire Weather Planning Forecast.
Today: Red Flag Warning across the entire area this afternoon
and evening due to RH values as low as 20-30 percent and gusty
southwesterly wind gusts up to 40 to 50 mph.
Wednesday: Strong winds (gusting 45-55 mph). RH will briefly
drop to 20-30% behind a dry line, but over most of the area that
will only last a couple hours in the morning before moisture
increases. However, minRH around 25-35% will linger longer near
and east of Hwy 63 in the afternoon. Elevated fire weather
concerns exist for these eastern areas. Little to no
precipitation is expected until light rain/snow Wednesday
evening into Wednesday night, but amounts are generally expected
to be less than a tenth of an inch.
Thursday: Dry (20-30 RH) but with high temps in the 50s. Sunny
skies and breezy winds. Thinking cooler temps, lighter winds,
and recent light precip the night before will prevent too many
concerns for Thursday, but may serve to dry fuels for a more
significant fire day Friday.
Friday: Elevated to significant fire concerns. Highs in the 60s,
minRH 20-30%, and southerly winds gusting to 30-40 mph
(strongest west) are in the forecast.
Next weekend: Greater moisture, lighter winds, and 50-60%
chances for rain will reduce fire concerns.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
KS...Wind Advisory until 8 PM CDT this evening for KSZ073-097-101.
Wind Advisory from 8 AM to 8 PM CDT Wednesday for KSZ073-097-
101.
Red Flag Warning until 8 PM CDT this evening for KSZ073-097-
101.
MO...Wind Advisory until 8 PM CDT this evening for MOZ066>068-
077>082-088>094-101-102.
Wind Advisory from 8 AM to 8 PM CDT Wednesday for MOZ055>058-
066>071-077>083-088>098-101>106.
Red Flag Warning until 8 PM CDT this evening for MOZ055>058-
066>071-077>082-088>097-101>105.
&&
$$
SHORT TERM...Soria
LONG TERM...Soria
AVIATION...Price
FIRE WEATHER...Soria