Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/30/22
Area Forecast Discussion
National Weather Service Gaylord MI
959 PM EST Sat Jan 29 2022
Issued at 959 PM EST Sat Jan 29 2022
Low pressure center has reached Northern Wisconsin late this
evening. Area of widespread light snow continues to develop ahead
of this system across much of Northern Michigan. Meanwhile...
persistent SW flow lake snow band remains offshore between Beaver
Island and our far Northern Lake Michigan shoreline from the
Straits thru Grand Traverse Bay. Some higher reflectivities are
beginning to develop further south along our Lake Michigan
shoreline around Leelanau and Benzie counties...coincidentally
where Winter Wx Advisories are in effect. Expect these two
counties will see 2 to 4 inches of new snow overnight with the
expectation that the SW flow lake snow band will push onshore as
low level flow veers to the W/SW later tonight. Will certainly
maintain this headline for these counties thru the overnight
hours. Rest of our CWA should see an inch or two of new snow from
the clipper system. Temps will generally hold in the teens across
Northern Lower Michigan thru the night...with temps dropping into
the single digits above zero across Eastern Upper Michigan.
.NEAR TERM...(Through Tonight)
Issued at 243 PM EST Sat Jan 29 2022
...Lake enhanced snow for nw lower MI tonight...
High Impact Weather Potential...Moderate. Accumulating snow in nw
lower MI tonight.
1010mb clipper low pressure is over n central MN. The low will
continue se-ward, reaching sw lower MI by daybreak Sunday. A
healthy sw-flow lake effect snow band has been marauding for much
of the day between Beaver Isl and the mainland of nw lower MI.
Ice cover over far northern Lake MI is contributing to minimal
penetration of this band into eastern upper MI. Not so visible on
radar, but snow showers are also developing into sw sections,
with 1-3SM vsbys presently at MBL and Frankfort. This is occurring
just as synoptic-scale moisture/ascent is increasing in advance
of the clipper.
Pure synoptic precip with this system would be anemic, with QPF
well under a tenth of an inch, even in favored places left of the
surface low track. The parent shortwave is weak, and broad-scale
moisture availability is poor in this persistently cold airmass.
850mb warm advection is respectable (and warm advection provides
much of our lift), but 850mb temps warming into the lower minus
teens still leaves enough instability for lake enhancement in
persistent sw flow. Vigorous lake effect earlier today lends
a little extra concern. Overnight, 1000-850mb winds veer from sw
to n, as the clipper approaches. That will push any stronger
offshore bands onshore, just before the event winds down in the
Hi-res guidance has been gradually increasing output QPF in nw
lower MI tonight. The ever-rambunctious HRRR has localized areas
of QPF >0.50" in parts of western Leelanau and Benzie Cos. That
seems overdone, but is at least well-placed. Snow-liquid ratios
won`t be as high as we`ve seen in some recent events; the DGZ is
placed somewhat above the max upward motion (which is in the
unstable layer closer to ground/lake level). That should keep SLRs
in the high teens, perhaps near 20. Synoptic winds will be light,
and blowing/drifting snow not a concern.
Total forecast snow accums have been boosted to 2-5" in Benzie/
Leelanau Cos, with the highest amounts within about 10SM of the
main body of Lake MI. An advisory has been posted for those 2
counties tonight. Manistee, Antrim, and Charlevoix Cos are the
next counties of concern, if the event ends up being a bit more
vigorous. Snowfall amounts fall off east of US-131, and those
areas (and eastern upper MI) seeing an inch or less.
Min temps will be mild tonight thanks to cloud cover, single
digits above zero in eastern upper MI, and ranging thru the teens
in northern lower.
.SHORT TERM...(Sunday through Tuesday)
Issued at 243 PM EST Sat Jan 29 2022
High Impact Weather Potential: Messy precipitation issues possible
Negatively tilted trough axis associated with the current east coast
storm is off to our east now...associated with a beautiful and
stereotypical comma-head-type response on water vapor satellite
imagery. A brief bit of ridging aloft has moved overhead (for the
Great Lakes) this morning...leading to some breaks in the clouds out
there...though some flurries and more intense snow showers do
persist. This ridging is the result of another niblet of energy
diving through the flow into the Upper Midwest through the last
several hours or so...with a surface reflection over southern
Manitoba/northern North Dakota this morning, positioned nicely in an
inflection point in the baroclinic zone aloft...and with some mid-
level moisture ahead of it, approaching northern Michigan attm. Do
note a weak surface low developing just north of Lake Superior with
an associated wavy surface boundary that extends back to the
Manitoba low. Cold front extends back to the northwest from the
latter low...and warm front (for a change) extends primarily
southward through the Plains, along the cusp of some +0C air out
there...ahead of longwave ridging, which continues to persist and
spread eastward across the western US, though do note some shortwave
troughing still trying to move through it...particularly a southern
stream trough approaching the coast of southern California.
Moving forward in time...will look for the niblet to our northwest
to dive through the region tonight...with additional subtle waves in
the upper level flow sliding through the Midwest Sunday into Sunday
night...as low off southern California today progresses across the
desert southwest in the next 24-48 hours, cutting through the base
of the ridge aloft. By Monday...will look for a complex flow pattern
across the CONUS...with split flow in play, given that southern
stream trough over the Gulf Coast. Northern Michigan will be under
the influence of ridging aloft...as we sit between departing
troughing from the weekend...and encroaching northern stream
shortwave trough (currently located in the Gulf of Alaska as of this
morning) that will have cut the top off the western ridge...and will
be propelled southeastward into the northern Plains by the core of
cold air aloft dropping back into north central Canada after
retrograding a tad over the weekend. Will look for that shortwave
niblet in the northern Plains to become negatively tilted as it zips
through the flow Monday night into Tuesday...with cold air flooding
southward into the northern Plains behind it...setting up a deeply
amplified trough aloft and resultant southwest-northeast oriented
baroclinic zone across the center of the country going into Tuesday
night...potentially into the Ohio Valley. This will have
ramifications for the pattern, as well as for our weather...going
into the latter half of the week.
Primary Forecast Concerns: Winds Monday night into
Tuesday...lingering snow Sunday...precip issues for the remainder of
Winds Sunday should be generally northerly behind the departing
system, and remain relatively light through the remainder of the day
and night...becoming west and eventually southerly with time through
the night...in response to the developing upstream system. Winds
will strengthen with time...particularly going into Monday night and
beyond...as pressure gradient will tighten up ahead of the
approaching front...in response to trough aloft becoming somewhat
negatively tilted as it passes by to our northwest. Would not be out
of the question to see winds in the realm of 10-15+kts Tuesday,
likely stronger over the lakes...noting 1000mb geostrophic winds
approaching or exceeding 50kts (typically a good proxy for the
tightness of the surface pressure gradient to use to estimate
surface winds...1/3 the value would be over-land wind values, and
1/2 the value for over-lake values). Low itself should remain to our
northwest...which should keep us in a position for warm advection
through basically the remainder of the short term. Warm advection
concerns may help mitigate some of the stronger winds from mixing
down from aloft Tuesday...as it will create a more stable atmosphere
that is generally unfavorable for transporting those stronger winds
downward from aloft...though some mixing may yet occur. Winds not
too far off the deck look to run around 50+kts, fyi...so depending
on any marine influences (which may occur on the Lake Huron side
this time, given southeasterly flow) and any other forms of mixing
during the day...it could be a little on the gusty side, for sure.
Something to keep an eye on going forward. Additionally...looks as
though a surface trough (potentially a cold front) may attempt to
move through from west to east Tuesday afternoon/evening...which
attm appears to be associated with a tighter isallobaric
gradient...favorable for a period of stronger gusts along this
front...actually, in the warm advection under surface pressure
falls...though some of the surface pressure rises behind the front
should result in a tighter isallobaric gradient as well...which
could become a concern for some areas going into Tuesday
Sunday morning...lingering snow should be winding down...as better
moisture departs southeastward through the day with the trough.
Subsidence aloft will be on the increase as heights rise behind the
shortwave...though there are some signals for some low-level
convergence in the vicinity of a lingering boundary across northeast
lower behind the initial surface low, which should (in theory) help
to squash most activity (for the most part...would not be entirely
surprised to see some rogue flurries still hold on in some areas,
though). Additionally...overlake instability lingers, with 925mb
temps around -10C still sufficient over Lake Michigan; a little
colder over Lake Superior suggests a slightly better chance of
lingering lake effect across the northern UP, though both areas
should remain in the presence of some boundary layer moisture
through the day. With some additional mid-level moisture sinking
southward Sunday night...may have to watch out for some snow
showers/flurries to make it to the surface...given southerly flow
over Lake Michigan again, in the presence of some low-level
convergence, may be favorable for some lake enhancement/seeder-
feeder action...though signals are not incredibly strong attm.
Monday...that mid-level/warm advection moisture/meager precip along
the thermal gradient aloft will be departing eastward...as warm
advection continues across the Plains and into our area through the
day Monday, noting wind profiles beginning to veer with height early
in the day. Overlake instability should wane through the day...as
warmer air advects in aloft...along with some subsidence aloft
beneath ridge ahead of the developing system to our
west...suggesting lingering lake effect will wane as well...as the
environment becomes less favorable. As we lose moisture aloft...and
with the warm advection through the day...if any boundary layer
moisture lingers...may have to keep an eye out for some "surprise"
freezing drizzle concerns, as we could become too warm in the
saturated layer for ice nucleation...particularly across eastern
Upper, where boundary layer moisture lingers through much of the
day. May have to watch for another round of some meager mid-level
moisture approaching for late Monday night into early Tuesday
morning...though it looks to be in the presence of some slightly
better forcing aloft ahead of the shortwave (best forcing attm looks
to remain to our north, closer to the shortwave itself).
Things become more tricky Tuesday. From a broad standpoint of
precipitation development...will look for some decent upper level
forcing in advance of that negatively tilted niblet passing by to
our northwest...with signals for mass divergence aloft continuing
into the latter portion of the day and the overnight...as the
initial shortwave lifts out...but jet max aloft moves just to our
northwest...placing Michigan in the favored right rear
quadrant/right entrance region of the jet. Southwest flow/warm
advection off the Gulf over the previous day should bring a moist
airmass into the area...potentially somewhat anomalous (pwats up
into the half inch range)...with surface dewpoints perhaps
approaching freezing (suggestive of snowmelt potential...not to
mention the potential of liquid precipitation). At present...do note
potential for temps aloft to rise above freezing Tuesday...and will
therefore have to keep an eye on the surface temperature forecast in
the coming days...as it will play a large role in precipitation type
issues going forward. All that being said...there are some signals
at least part of the area may get in on a dry slot with this
system...with the bulk of the precipitation remaining to our south
where mid-level moisture appears to be maximized...(though some
seems to hold on across the UP as well)...so will have to keep a
close eye on this going forward...as it looks like it could be quite
.LONG TERM...(Tuesday night through Saturday)
Issued at 243 PM EST Sat Jan 29 2022
High Impact Weather Potential: Watching midweek system for next
week...with potential for lake effect behind it...
By Wednesday...will look for that aforementioned baroclinic zone to
be somewhere across the Midwest/Ohio Valley as a steep but
positively tilted trough axis extends from a sub-500dm 500mb low in
the Hudson Bay region...southwestward into the Desert Southwest. As
colder air advects southward into the region...will look for the
upper level jet over the baroclinic zone to intensify in
response...and surface pressure falls will also result along this
boundary. Guidance is still somewhat unclear on how this
evolves...and timing/track seems to be shifting around some as
well...but looks like we should remain active through the remainder
of the week. Mid-late week system for Wednesday/Thursday...and
perhaps now into Friday...? will be the one to watch...as there are
signals for some anomalously moist air to flood northward along the
boundary, given a good tap of Gulf moisture for a change, noting the
deep troughing extending into the southwestern US. Exact position,
therefore, of the baroclinic zone will need to be watched closely in
the coming model runs...as it will play a major part in the track of
the surface low that develops...among other concerns, including the
extent of cold air that is able to break into our region again...and
resultant lake effect related to the cold air returning.
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 600 PM EST Sat Jan 29 2022
A clipper system currently centered over Northern Minnesota will
slowly drop SE thru Wisconsin tonight...reaching the southern tip
of Lake Michigan by early Sunday morning. The low will continue to
slide SE thru Indiana Sunday morning...reaching the Ohio Valley
Sunday afternoon. Light synoptic snow will continue to gradually
develop this evening along the eastern side of this system.
Sufficiently cold air will provide some SW flow lake enhancement
for some locations along the shoreline counties of Northern Lake
Michigan. Mainly low VFR/MVFR conditions are expected for the next
24 hours...periodically dropping to IFR within some of the heavier
snow showers across far NW Lower Michigan tonight into Sunday
morning. Surface winds will remain from the S/SW under 10 kts
tonight into Sunday morning...and will then shift to the N/NW on
Sunday as the low center passes south of Michigan.
Issued at 343 PM EST Sat Jan 29 2022
A clipper passes to our south early Sunday. Ongoing sw to s winds
will veer northerly overnight and Sunday, while remaining on the
light side. Stronger southerly winds will develop on Monday
(especially on Lake MI), which looks like our next chance for
advisory and/or gale-level winds.
MI...WINTER WEATHER ADVISORY until 7 AM EST Sunday for MIZ020-025.
Area Forecast Discussion
National Weather Service La Crosse WI
528 PM CST Sat Jan 29 2022
.SHORT TERM...(Rest of the weekend)
Issued at 217 PM CST Sat Jan 29 2022
A mix of sun and mid to high clouds this afternoon with warm air
advection underway ahead of a surface low positioned over northern
Minnesota. Temperatures will continue to climb through the 20s with
a southerly breeze in place. BCK and ONA have even managed to
crack 30 degrees at this hour.
That surface low and accompanying cold front will drop southeast
through the area heading into this evening. Not really impact aside
from increasing northwesterly winds. Cold air advection will support
some momentum transfer after dark mainly in open areas west of the
Mississippi River, where gusts of 20 to 30 mph will be possible for
several hours overnight. Rather low confidence in tonight`s low temp
forecast given uncertainty about extent of clouds as well as the
decent CAA and low level mixing. Not surprising, there`s very wide
spread in tonight`s minT guidance. For now have raised minT forecast
closer to 50th percentile, which seems reasonable given more
The pressure gradient quickly relaxes Sunday morning as a surface
ridge builds overhead. Maybe a smidge cooler than today, but
otherwise a very similar day. A weak mid-level wave will drop
through Sunday afternoon-evening, accompanied by a push of slightly
greater atmospheric moisture. Depth of column saturation is still
uncertain; some forecast soundings show a bit dryness in the low
levels, while RAP fully saturates briefly. Regardless, forcing and
moisture look marginal, so have just added chance of flurries from
.LONG TERM...(Monday through Saturday)
Issued at 217 PM CST Sat Jan 29 2022
Rising 500mb heights on Monday will translate into a warmer day
across the region with some areas potentially jumping briefly above
freezing. A decent shortwave and moisture transport will cross the
region late Monday night into Tuesday with the surface low scooting
by just north of the Canadian border. QG forcing will be most
robust near the surface low, so for our area it only looks like
meager support for light snow north of I-94. That said, NBM
continues to keep a dry forecast for our area. Tuesday`s
temperatures will begin to drop in the afternoon behind the strong
Attention then turns to another blast of arctic air for the second
half of the week, along with a midweek system that is largely poised
to stay south of our area. 850mb temps will again plunge to the
teens to 20 below zero Wednesday through Friday. Expecting low temps
to again tumble below zero for most with Thursday night looking to
be coldest. Additional wind chill advisories certainly seem
plausible for parts of the area through the latter half of the week.
Beyond that, looks like some moderation into next weekend.
A strong baroclinic zone will set up from the Central/Southern
Plains into the eastern Great Lakes by midweek. A pronounced
shortwave trough ejecting from the Desert Southwest will interact
with this setup, with greatest resultant impacts looking to largely
stay well south of the forecast area. That will be thanks in large
part to a strong, Canadian surface high building in from the Dakotas
and dry northerly flow. There`s been a definite southward shift
among GEFS/EPS ensembles within the last 24 hours. Vast majority of
EPS members now keep nearly all of our area dry, except for our far
southeast (i.e. Grant County). GEFS has a greater number of members
still bringing snow a bit further north into our area, but they`re
in the minority and largely confined to our far south. Still a
number of unknowns, but for our area, confidence is slowly growing
toward seeing only minimal impacts from this system. Our far
southeast has the biggest question mark, though any potential snow
grazing the area look to be on the light side. Nevertheless, there
are still some outlier ensemble members suggesting several inches
from DBQ to PVB southward. Will continue to closely monitor storm
evolution and trends.
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 556 PM CST Sat Jan 29 2022
A surface low currently in MN will bring clouds into the area
tonight, lowering ceilings from VFR to MVFR conditions first at KRST
then at KLSE. Ceilings will continue to lower into the morning, with
IFR conditions possible at both TAF sites. Otherwise, southerly
winds will become northwesterly, with gusts up to 23 kts possible at
KRST for a couple hours overnight.
Area Forecast Discussion
National Weather Service Boston/Norton MA
658 PM EST Sat Jan 29 2022
A powerful winter storm will exit the region as it lifts
northeastward into Nova Scotia tonight. Minor coastal flooding
will impact much of eastern Massachusetts this evening.
Dangerously cold wind chills are anticipated for parts of the
region. This is due to the combination of gusty winds and cold
temperatures. Drier weather returns with below normal
temperatures Sunday before a warm up next week.
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
645 PM Update...
No major changes in the latest update. Main concern is the band
of heavier snowfall over central MA into eastern CT/western RI.
Expect this band to become more diffuse in the 1-3 hrs as colder
drier air advects in from the northwest and the 700 hPa closed low
lifts into the Gulf of Maine. Once this wraps up think there
will still be some light snow until late tonight, but not
anticipating much more in the way of accumulation. Thinking 1-3
inches additionally at the most with the highest totals on the
Cape. Rest of forecast on track.
* Snow coming to an end as the winter storm lifts toward Nova
* Blowing snow remains an issue overnight as winds remain gusty.
Have a very cold airmass moving in behind the system and this
in combination with gusty winds will bring dangerously cold
wind chills to parts of the region.
Closed off 500 hPa low just over/east of southern New England
will lift into Nova Scotia by late tonight.The deep cyclone
associated with this feature will lift into Nova Scotia late
tonight. Behind this system high pressure nudges in from Mid
Have kept all Winter Weather headlines including the Blizzard
Warnings up as it is still taking a bit for winds to come down
and snowfall to taper off. Actually may be able to gradually
take down these headlines across portions of the interior as the
snow tapers off, but for the most part ending times look good.
The other issue we run into tonight is with the fluffy snow and
strong winds will have blowing snow reducing visibilities and
going over cleared roadways. This could still make travel
hazardous, so folks should probably still stay off the roads to
allow crews to clear things.
Still watching this frontogenetical band over eastern portions
of the CWA to lift northeastward. Currently have it pegged just
NW of the 850-700 hPa Fgen on SPC Mesoanalysis. The RAP has had
a pretty good handle on this for most of the day and expect
this to move northeastward. Thinking this ends by roughly 02Z.
Still may have some light snow until late tonight until the low
moves into Nova Scotia. Anticipate that there could be an
additional 1-3 inches of snowfall with the highest amounts over
Cape Cod as it will take the longest for snow to end here.
Should be over after 06Z. As previously mentioned the main risk
will still be blowing snow overnight as gusts will be 25-40 kts
until 06Z. Gusts diminish to 10-30 kts with the highest values
across the eastern Cape.
Will see northwesterly flow advect in -15 to -20 degree air at
925 hPa. Have nudged down low temps into the single digits above
zero for most of the area except the Cape/Islands where it is in
the low to mid teens. Given the strong winds coupled with the
cold temps expecting dangerously cold wind chills down to
roughly -15 to -20 degrees Fahrenheit. Have hoisted a Wind Chill
Advisory for the eastern slopes of the Berkshires and Worcester
county. Not out of the question that portions of CT need a
headline in future updates.
See coastal flooding section for discussion.
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
* Dry and quiet weather with below normal temperatures.
Did not pay too much attention to this period given the winter
storm moving through the region. Ridge axis builds into the
eastern Great Lakes for Sunday before a shortwave lifts through
Sunday night into early Monday. High pressure nudges into the
region just south of us for Sunday and into Sunday night.
No major concerns during this period other than breezy
conditions coming to an end Sunday morning. High temps around 10
degrees cooler than normal for this time of year with readings
in the low to mid 20s. Low temps Sunday night into Monday
generally in the single digits, but not anticipating wind chill
issues given the lack of winds. There will be a bit of
cloudiness Sunday night.
.LONG TERM /MONDAY THROUGH SATURDAY/...
5 AM update...
* Quiet and increasingly mild weather to follow through much of the
* Rain returns Thursday into Friday
Sunday and Monday...
A trough east / ridge west pattern continues late weekend and early
in the week while a ridge of high pressure moves in at the surface.
Initial NW mid level flow will bring 850 mb temps down near -15 C on
Sunday making for a cold day with highs only in the low to mid 20s;
fresh snow cover, though, might keep highs a few degrees lower than
that. This, together with breezy winds thanks to the lingering tight
pressure gradient means it will feel more like the single digits and
low teens. Wind gusts to 25 to 35 mph over the water and the cold
temperatures will also lead to freezing spray issues. A Freezing
Spray Advisory is in effect Sunday morning. By Monday that steering
flow becomes more westerly advecting marginally warmer and more
moist air into southern New England. Skies will be clear on Sunday
with a mix of clouds and sun on Monday thanks to that increase in
Tuesday through Friday...
High pressure moves overhead on Tuesday with an mid level ridge axis
and warming temperatures before our next chance of wet weather on
Wednesday. This as a low passes to our north over the Great Lakes
and northern New England pulling a warm front north across the
region early Wednesday. This brings much milder temperatures with
it, in the mid 40s Wednesday and near 50 Thursday, along with
scattered rain chances on Wednesday. The cold front hangs up to our
west, keeping the region beneath moist southwest flow through at
least Thursday. PWATs surge over one inch on Thursday ahead of the
cold front and incoming mid level trough. Forcing from the trough,
cold front, and right rear quadrant of a 150 kt upper jet will work
together with all that moisture to bring a soaking rain around
Thursday or early Friday. Too soon for details like timing, whether
it turns to snow on the back side, etc but this could be a decent
slug of rain.
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Tonight...High confidence in trends, moderate in exact timing.
Moderate snowfall coming to an end with lighter snowfall until
roughly 01-04Z for most, but 06-09Z for the Cape. Slowly improving
to MVFR and eventually VFR ceilings by late tonight. However,
given the fluffy snow and gusty winds will have considerable
blowing and drifting snow across the region late tonight.
Thinking once the gusts get below 20 kts should see this risk
come to an end. Thinking visibilities will be generally in the
MVFR range, but may have some spotty IFR in any higher gusts.
VFR with clear skies. Breezy during the morning with W/WNW winds
and gusts of 15-20 kts. Not much of the way of gusts during the
Sunday night...High confidence.
VFR with increasing mid to high clouds. Light SW/S winds.
KBOS Terminal...Conditions gradually improving to MVFR/VFR with
blowing snow until roughly 06-08Z.
KBDL Terminal...Conditions improving to VFR. Could have some
visibility reductions due to blowing snow until roughly 03-06Z.
Outlook /Monday through Thursday/...
Monday through Tuesday: VFR.
Tuesday Night: Mainly VFR, with local IFR possible.
Wednesday: VFR. Slight chance RA.
Wednesday Night: Mainly VFR, with local IFR possible. RA
likely, chance SN.
Thursday: MVFR. Breezy. RA.
Forecaster Confidence Levels.
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Powerful Nor`easter will lift toward and into Nova Scotia.
NW storm-force gusts should continue until roughly 9 PM to
midnight, then become around gale force (35-40 kt) for the
overnight across the NE waters. Seas will tend to decrease
though some initial 20-25 footers still possible thru midnight
on the eastern offshore waters. By daybreak, expect seas 6-10 ft
on the southern waters, and 9-12 ft with increasing period.
Risk for freezing spray will continue, with improving visibility
as snow tapers off/shifts NE late tonight.
Sunday and Sunday night...High confidence.
Freezing spray continues through Sunday morning, but should
become lighter by the afternoon as the gusty W winds lessen.
Seas of 7-12 feet during the morning diminishing to 4-7 feet by
late Sunday afternoon. Seas fall to 1-4 ft Sunday night.
Outlook /Monday through Thursday/...
Monday through Monday Night: Winds less than 25 kt. Seas
locally approaching 5 ft.
Tuesday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Tuesday Night through Wednesday: Winds less than 25 kt. Seas up
to 5 ft.
Wednesday Night: Winds less than 25 kt. Areas of rough seas.
Chance of rain.
Thursday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Rough seas up to 9 ft. Rain likely.
Still expecting minor coastal flooding with this evening`s high
tide, thus have kept the coastal flood advisory in effect for
this evening. Stevens Institute guidance still looking good
with surges around 1-2 feet, but gusty winds will be much less
than earlier today along with a lower astro tide.
CT...Winter Storm Warning until midnight EST tonight for CTZ002>004.
MA...Blizzard Warning until midnight EST tonight for MAZ005-006-013-
Coastal Flood Advisory until midnight EST tonight for MAZ007-
Blizzard Warning until 5 AM EST Sunday for MAZ007-015-016-019-
Winter Storm Warning until midnight EST tonight for MAZ003-004-
Wind Chill Advisory until 10 AM EST Sunday for MAZ002-004-008-
Winter Weather Advisory until midnight EST tonight for MAZ002.
RI...Blizzard Warning until midnight EST tonight for RIZ001>008.
MARINE...Storm Warning until midnight EST tonight for ANZ230>237-250-
Freezing Spray Advisory until noon EST Sunday for ANZ231>235-
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
526 PM CST Sat Jan 29 2022
Issued at 305 PM CST Sat Jan 29 2022
Through Sunday night...
Overall, the short term period should be fairly quiet weather-wise.
A weak surface low is expected to move across the area late this
evening with an associated cold front pushing across the area
turning winds northwesterly overnight. Strato-cu should fill in
behind the front brining a chance for a few flurries Sunday
morning coinciding with a vort max moving overhead.
There remains a weak signal for light lake effect snow showers into
northwest Indiana during the day tomorrow. Little to no
accumulation is expected with this, other than perhaps a light
dusting. The ECMWF and even the HRRR trend a bit further west
into Cook county rather than into NW Indiana as the NAM suite
suggests, so opted to hang on to a mention of flurries across
southeast Cook County into the afternoon tomorrow. Overall not
expecting much in the way of impacts from this. Will note that
there is a non-zero chance for some light freezing drizzle given
if the cloud layer temperatures are a bit warmer limiting ice
nucleation. Something to keep an eye on.
Temperatures tonight will warmer than what we saw last night thanks
to some additional cloud cover and warming from today`s southerly
flow, dropping into the teens for most areas. High temperatures
tomorrow will also be a bit warmer than what we saw today, in the
mid to upper 20s.
Issued at 320 PM CST Sat Jan 29 2022
Monday through Saturday...
Main forecast concern and focus continues to be the potential for
a higher impact accumulating snow event Tuesday night through
Wednesday night, and possibly Thursday as well. Confidence remains
above average in big picture idea of a regional winter event in
portions of the Midwest. However, key guidance differences in
handling the pattern lend to lower confidence in the answers to
the all important questions of when (start and especially end
timing), where (the highest totals occur), and how much snow in
the heaviest axis.
On Monday and Monday night, lead wave and associated surface low
from the Canadian Prairies to northern High Plains will drag a
warm front gradually northward. Late day highs are forecast to
reach the lower to mid 30s after a seasonably chilly start. Monday
night will feature steady to slowly rising temperatures amidst
breezy southerly winds. The surface low will be near Lake Superior
by 12z Tuesday, with its trailing cold front near the MS River.
The front will move across the area during the day on Tuesday,
with light rain or showers developing in the vicinity of and
behind the frontal zone, particularly for the southeast half or so
of the CWA. Ahead of the cold front passage, we`re currently
advertising most locations tagging 40+ degrees for the first time
since January 18-19. Expect steadily falling temps behind the
Tuesday evening/night through Wednesday night and into Thursday is
the time window of concern for impactful accumulating snow and the
important differences in handling the pattern crop up right away.
Initial snow would be of the over-running variety. Lead short-
wave energy will interact with a sharpening baroclinic zone
across the region in the favorable right entrance region of an
anti-cyclonically curved jet streak arcing to the north of the
Great Lakes. This will occur north of a surface low pressure
trough extending northeast from the southern Plains, while strong
Arctic high pressure of 1045+ mb builds in from the northern High
Plains. Open Gulf of Mexico moisture trajectories into the area
will provide plenty of moisture to tap into, with PWAT plume into
central IL and IN pushing or exceeding 200% of early February
There are key big picture features and other more complex
elements, and the evolution of all these moving parts will
determine how this all plays out. Big picture features of note
include: a deep trough (negative height anomaly) to over the
interior west/southwest; a stout tropospheric polar vortex lobe
over Hudson Bay; and downstream positive height anomalies over the
eastern US and Canada. Another important final piece of the
puzzle is a currently subtle short-wave out near the
International Dateline southwest of the Aleutians that will round
the southwest trough and *potentially* lead to a stronger low
pressure to close out the stretch.
Here`s a breakdown of 3 general clusters of outcomes, in which the
12z global operational models fit decently into:
1) Weaker and farther north Hudson Bay PV will allow for slightly
more pronounced eastern height rises, which enables strong
moisture surge Tuesday evening and night to reach farther north
into the CWA for potentially significant snow accums into Wed eve.
The short-wave out over the eastern Pacific is slower to eject
and positively tilted and subsequent stronger synoptic system
later Wednesday night into Thursday takes off too far south and
east for meaningful additional snow (aside from any lake effect
Similar 12z model run: ECMWF
2) Weaker and farther north Hudson Bay PV, more pronounced
downstream ridging allows for moderate to heavy overrunning snow.
THEN southwest short-wave takes on neutral to negative tilt and
ejects out to favorably develop a stronger system with ~1005 mb
surface low tracking near or north of Ohio River. This progression
would bring another round of moderate to heavy snow along with
even stronger winds into or through Thursday, aided by impressive
right entrance region jet dynamics. In most amplified ensemble
members, could even be some wintry mix p-type issues in parts of
Similar 12z model run: GFS
3) Stronger and farther south Hudson Bay PV lobe results in
confluence and slightly suppressed positive height anomalies, and
the strong/drying influence of incoming Arctic high to have more
influence. Result would be banded overrunning precip having a very
sharp northern cut off and focus the heaviest precip and snow axis
into our southern CWA and points south and east (or even south of
CWA altogether in most northern stream dominant ensemble members).
Similar 12z model run: Canadian.
Suffice to say that all three of these outcomes remain plausible
and represented by the distribution of ensemble members of the
three parent models. Overall, there is *currently* a slight lean
in the ensemble means toward roughly outcome 1, favoring our
southeast half or third, occurring amidst brisk northerly winds.
For this reason, the most recent WPC Day 5 accumulating snow/sleet
outlook appears reasonable with southeast half having higher
(50-70% probabilities) vs. northwest (30-50% probabilities). Since
the three approximate clusters described above remain plausible
outcomes, we continue to urge caution with any individual model
run snowfall outputs being shared. Stay tuned for updates as the
potential event draws closer when we can be more confident on some
of these still uncertain details.
How cold it gets in the very cold air mass in the wake of the
system will be determined by magnitude of the air mass and also if
we can get favorable radiational cooling conditions under surface
high pressure. There will also be a risk for lake effect snow
showers, location details TBD Thursday night into Friday. This
will be followed by moderation but likely still below normal temps
for next Saturday.
For the 00Z TAFs...
No significant aviation concerns. A weak cold front will move
across the terminals early Sunday morning resulting in a wind
shift to the northwest. Maintaining MVFR CIGS in the TAFs for
Sunday though confidence in MVFR conditions is low and CIGS may
end up being VFR. Given low confidence, opted not to change the
previous TAFs which had MVFR cigs.
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...Updated Aviation Forecast Discussion...
Issued at 223 PM CST Sat Jan 29 2022
Temperatures are higher and dew points are less than originally
forecast. Thus, counties west and along a ling from Beatrice to
Lincoln to Norfolk have been updated to a Red Flag Warning until 6
A cold front will move across the area tonight and make a cooler
day on Sunday, with highs in the 40s. Warm advection and southwesterly
flow on Monday are expected to make temperatures to climb into the
mid to upper 50s. An upper short wave trough moving across the
Dakotas will bring a cold front across the area on Monday night.
On Tuesday highs will be in the 30s. The aforementioned upper
level trough that moves across the Upper Great Lakes, A deep upper
level trough starts digging across the central Rockies and Desert
Southwest. Isentropic lift and warm advection extending along and
north of a front from Oklahoma into Missouri. Models differ in
where this front sets up and how much energy comes out of the deep
trough. Snow will be north of this front and at this time it
appears that the axis of the heaviest snow is expected to be
across northern Kansas to northern Missouri.
After this system clears out of the area on Thursday, Arctic high
pressure moves into the Missouri Valley and temperatures will rise
only to the teens on Thursday. Lows on Thursday night are expected
to drop below zero.The remainder of the period looks to be dry
with a gradual warmup.
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 523 PM CST Sat Jan 29 2022
At present, VFR conditions prevail across at all three TAF sites.
Northwest winds with gusts 18-23kt at KOFK and KLNK will abate by
01-02Z. Backdoor cold front moving through southern portions of
forecast area, cooler and more moist airmass will follow in its
wake, lagging 9-10 hours. RAP, HRRR and NAM advecting MVFR
ceilings into all three TAF sites between 09-11Z. HSREF hints at
development with 20-40% probabilities of ceilings below 1K.
Ceilings appear to remain intact through morning, so did not
include improving conditions in TAFs for now.
NE...Red Flag Warning until 6 PM CST this evening for NEZ016-030-031-