Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/07/22
Area Forecast Discussion
National Weather Service Columbia SC
639 PM EST Thu Jan 6 2022
A cold front will move through the region tonight with a few
showers. High pressure along with cooler and drier air will
move into the region for Friday and Saturday. Fair and warmer
Sunday ahead of a front that will move through Sunday night and
early Monday, providing a better chance of showers. Cool and dry
conditions then persist through the middle of next week.
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
At 23z a cold front is approaching the Upstate SC. Warm
advection and some limited moisture (shallow) is resulting in a
band of mainly light showers in the Piedmont SC and east
central Ga ahead of the front. These showers will move through
the area this evening but likely diminish since the air mass
remains relatively dry...and drier than models suggested
earlier. So cut pops back from previous forecast and any qpf
will be quite limited. The latest guidance favors the CSRA for
qpf where precipitable water may increase to 0.80 inches...so
pops higher there. Based on the HRRR and Rap, the front moves
through the central Midlands around Midnight. Clearing behind
the front with some gusty winds so continued the Lake Wind
Advisory...due to warmer water expect mixing. Winds should
diminish toward daybreak.
The front is progged to be offshore by the early morning hours
with skies clearing from west to east as the sun rises. Though
the incoming airmass will be much cooler and drier, low
temperatures will not completely bottom out due to a well- mixed
PBL, compliments of those northwest winds. Overnight mins
therefore expected to range from the upper 20s/low 30s along and
north of I-20 to the mid 30s toward the coastal plain.
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
Cold front pushing toward and through the area today will be moving
east and away from the area on Friday. Mid-level confluence and
subsidence behind the departing shortwave trough will help to clear
any additional cloud cover out quickly, and will help make Friday a
nice day. Weak surface northeasterly flow will commence, with cold
and dry air advection through the day. Surface high pressure will
quickly begin to settle into the Mid-Atlantic by Saturday morning.
As a result of all of this, Friday will be cooler and drier. Highs
may be a tad warmer than otherwise owing to weak downsloping, and
this should help to keep us fairly dry at the surface as well.
Expect highs ranging from the mid 40s north to the low 50s south.
Friday night should be a cold one, but how cold is going to depend
on how much winds can fall off Friday night. It looks like it will
be a clear night, but with high pressure remaining to our north, I
am skeptical that we`ll have ideal radiational cooling conditions.
I`ve nudged forecast lows up a bit to account for winds staying in
the 3-6 mph range overnight. Still, expect a cold night with lows
likely in the 24-30F range. Saturday will be another nice, albeit
cool, day. We`ll be underneath surface ridging, and will likely end
up in the upper 40s to around 50F for highs again. Saturday night
should be a bit warmer as the surface high shifts eastward. This
should result in some moisture advection, which will keep our lows
in the low and mid 30s.
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Temperatures will quickly moderate again on Sunday as we continue
this roller coaster that we`re on (at least temperature wise).
Shortwave ridging from Saturday will quickly shift east as a
longwave trough digs into the eastern US on Sunday. This will be
associated with a strong Canadian high pressure pushing into the
central US. The combination of these two things will result in a
strong but quick cold front developing and pushing towards the
region by Sunday night. Ahead of this front, widespread
southwesterly flow and some compressional warming ahead of the front
will likely result in above normal highs in the low to upper 60s.
Operational models and ensembles are all in good agreement that this
will likely be approaching by 7p on Sunday and push through between
1a and 7a early Monday morning. Ahead of this, guidance suggests a
PW plume that will contain values near 200% of normal, which should
lead to widespread rainfall developing. Given the quick nature of
the front, we won`t see a long duration rainfall event. However,
given soundings indicative of warm & moist profiles, we should get
efficient rainfall. Current thinking is that everyone will likely
see at least 0.25" of rain, with the ensemble means ranging between
0.25" and 0.75". The most rain will likely fall across our northern
& western counties closer to the best shortwave trough and
forcing. There may be some isolated thunder but nothing
widespread is expected given that model soundings are indicating
little to no CAPE.
Once the front moves in, a cooler and drier airmass will usher in
for at least the beginning of next week. NAEFS & ECM indicate that
this 1032-1036 sfc high pushing in for next week will be in the 90-
97th percentile for this time of year, suggesting that we`ll have
some cooler than normal temps on Monday, Tuesday, and possibly on
Wednesday. High temps will likely range from the mid 40s to the mid
50s each day, with Tuesday expected to be the coldest day as the
surface high settles in. Ensemble guidance is in good agreement for
several runs on placement/timing and strength of this high, leading
to above normal forecaster confidence in this solution. Lows will
likely be in the mid 20s to low 30s range each night, with Tuesday
night likely being the coldest night. It`ll depend on the eventual
track of the surface high, but if we are centered underneath the
high & get ideal radiational cooling, some areas will likely end up
in the low 20s on Wednesday morning. But those details will be
ironed out over the coming days. Dry weather is expected after the
Sunday night front through the end of the period as low PW air
settles in with the strong surface high. High temperatures will
likely begin rebounding to near/slight above normal values again on
Wednesday and Thursday.
.AVIATION /00Z THURSDAY THROUGH TUESDAY/...
Surface low pressure moving by to the north with a cold front
pushing through the area this evening. Showers associated with
this front will move over the terminals shortly after 00z. With
low levels relatively dry, however, widespread restrictions are
unlikely. TEMPO MVFR CIGs and VSBYs possible at AGS/DNL but
remain unlikely elsewhere. Winds are currently out of the south
but will switch to westerly behind the front and increase with
gusts between 15 to 20 knots. By early Friday morning wind
gusts will decrease with winds remaining out of the NW between 5
to 10 knots with clearing skies.
EXTENDED AVIATION OUTLOOK...Restrictions possible Sunday and
Sunday night as the next low pressure system and associated
cold front cross the region.
GA...Lake Wind Advisory from 10 PM this evening to 7 AM EST Friday
SC...Lake Wind Advisory from 10 PM this evening to 7 AM EST Friday
Area Forecast Discussion
National Weather Service State College PA
1000 PM EST Thu Jan 6 2022
A quick-hitting snowstorm will impact central Pennsylvania
through early Friday morning. Blustery northwest winds will
produce single digit wind chills in the Alleghenies tonight into
Friday and lake effect snow across the northwest snowbelt
Friday morning into Friday night. Expect fair weather on
Saturday with a period of freezing rain/ice likely Sunday
morning. Another period of lake effect snow is likely on Monday
along with sub-zero and positive single digits wind chills
forecast Monday night into Tuesday.
.NEAR TERM /THROUGH FRIDAY/...
Nice snow band easily visible on the radar from Harrisburg to
Chambersburg. Already a few 2" reports from the southern tier,
and the good band of snow is morphing some right now. The HRRR
progs put the band on a pivot over the SErn counties for the
next 3-6 hrs. The timing of snow end looks very solid with prev
fcsts, but intensity now looks higher/heavier for a few hours
between now and 08Z in the SE. Thus, have bumped the snow
amounts up 1-2" in that area, which bumps them over winter storm
warning criteria of 5"/12hrs. The rest of the area has the
forecast rolling along excellently. Snow intensities are as
expected there. Bumping Schuylkill Co snow total, too, but they
have a 6" criteria, and may be too far north for the best band.
Snow is right on time and is gradually making it down through
the dry air at the sfc. As of yet, no heavy snow obs seen in PA,
but some going below 1SM. First few hours of the QPF from 18Z
runs over the SW have likely been a little high, but this is to
be expected with the snow struggling to get to the sfc. With
the progression of things so far being so close to the going
forecast, and with the newest 18Z guid looking solid, no
significant changes are in store for this update.
Visible sat/regional radar loops show increasing mid-high
clouds covering CPA this afternoon with snow spreading
northeast across WV. We expect a snow onset time between 5-7PM
across the Laurel Highlands/southwest Alleghenies with snow
spreading quickly to the northeast through the remainder of the
Guidance remains pretty consistent in taking amplifying
shortwave ESE from the central High Plains into the lower OH
Valley by 00Z Fri before taking on a negative tilt and shifting
east to the Mid Atlantic coast. Coastal low pressure
consolidates over the southern Delmarva/VA Tidewater around 06Z
Fri before rapidly developing as it lifts north toward the New
We were keen to make several incremental changes to the previous
forecast (which was largely in pretty good shape):
1. A slight increase in snowfall amounts from south to north.
2. Expansion of winter weather advisory north to I-80 corridor
3. Start time adjustments the previous winter wx advisory
4. New winter weather advisory for Warren County (lake effect)
The increase in snowfall is supported by the latest WPC WWD, NBM
and HREF mean. This pushed totals into the low-end advisory
category for most counties along the I-80 corridor. We also
considered a winter storm warning for Somerset County with some
locations coming in with 6-7 inches. Later shifts can upgrade if
needed, but for now we decided on a high-end advisory 4-6".
Headline start time adjustments were minimal pushed back 1-2
hours, however the end times may need to be extended as latest
hires models keep snow going into the predawn hours Friday.
Band of moderate snow should take aim on the southern
Alleghenies this evening into early tonight, then pivot and
shift toward the I-81 corridor. Increasing FGEN forcing has us
concerned that heavier snowfall amounts may occur near and
southeast of I-81 which is a feature that most hires model
guidance appears to be honing in on. The updated WPC WWD also
captured this feature in the latest cycle, so that will be
something to watch closely this evening. Overall, max snowfall
rates should remain in the 0.50 to 1 inch range with the highest
probability 1hr rates >1" over along and southeast of I-81
from ~ 1-6AM or during the predawn hours.
Snow character will be a dry/fluffy snow with temps in the 20s
and SLRs in the 12-18:1 ratio based on a blend of WPC and NBM.
The lower ratios are shaded toward the southeast part of the
Northwest winds will increase late tonight through early Friday
morning with gusts 20-25mph over the Laurels by daybreak. The
blustery winds combined with temps falling into the upper teens
will produce single digit winds over the western mtns by
Synoptic snow should taper off from west to east during the
predawn hours. However, the increasingly cold and gusty west-
northwest flow will result in developing lake effect snow
showers across the Allegheny Plateau late tonight. Low temps
will range from the mid teens over the Alleghenies to the mid
20s in the southeast; but it will feel colder when factoring the
.SHORT TERM /FRIDAY NIGHT/...
Cold and blustery conditions expected on Friday. Model
soundings support max gusts between 30-35 mph with the highest
winds around 40 mph on the ridgetops across the southwest
Model indicate some very dry air flowing south across the Grt
Lks Friday. However, steep lapse rates, high inversion heights,
lowering DGZ, possible Huron connection and snow/water ratios
near 20:1 should result in several inches of fluffy snow across
the snowbelts of Warren County. We were keen to upgrade to a
winter weather advisory with 2-4" of lake effect snow expected.
Locally higher amounts are possible especially in the northwest
part of the county.
Max temps don`t recover very much from morning lows with a
narrow diurnal range expected. Highs Friday trended colder and
now range from the upper teens in the Laurels to around 30F in
the southeast (first day this winter of sub-freezing temps
across the CWA). It will feel even colder when factoring the
wind with max ApparentTs in the single digits and teens.
Expect LES to taper off with clearing skies and diminishing
winds Friday night as high pressure builds into CPA. A cold
night with lows in the single digits to mid teens.
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Fair weather and light wind is expected Saturday, as surface
high builds across the state. Model RH profiles support abundant
sunshine and GEFS 2m temp anomalies suggest highs will remain a
few degrees below average, mainly upper 20s to low 30s.
Main focus of this period is near the beginning as a favorable
setup for a light mixed precipitation and icing event is slated
for late Sat night/Sunday, as warm front lifts across the region
Sat night into Sunday followed by weak shearing cold front.
Precipitation is not expected to be heavy, but the slow moving
decaying frontal zone sagging across the region with ambient
cold air in place at the low levels and widespread warm layer
aloft promises to result in a mix of mainly sleet and freezing
rain, with many central PA valley locations likely to remain
near freezing through Sunday afternoon as precipitation
A warm front will push through the region Saturday night into
early Sunday. Latest guidance suggests up to 0.25"+ of QPF with
the approach of the front, again mostly falling as an icy mix
of sleet and freezing rain. With antecedent 1030 hPa cold high
pressure system in place on Saturday (temps in the 20s Sat
night), ground temperatures after midnight Sat night and Sunday
morning will be supportive of ice accretion. Air temps will
slowly warm through the day Sunday, but ground temperatures may
lag behind and stay below freezing for a couple of hours longer.
Expect to need additional time for travel on Sunday.
Colder, drier conditions are likely behind the front early next
week, with any snow showers likely limited to the typical lake
effect snow belt.
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
MVFR cigs holding over the NW this morning and will likely
remain through this afternoon. Later in the afternoon and
evening, a storm system will bring snow to all airfields. Snow
will reach JST and AOO first by 22z, then spread north and east
through the evening. Reductions in vis and cigs likely in SHSN.
Snow will be light for the most part, but heavier bands of snow
remain possible along the south /JST, AOO, MDT, LNS/. Snow will
be out of most places by Friday morning, with lake effect snow
showers at BFD for Friday.
Fri...Lingering snow showers and restrictions possible north
and west. Becoming VFR elsewhere.
Sun...Lowering conditions bring restrictions in rain or wintry
Mon...VFR across the southeast, chance of snow showers across
the north and west.
Winter Weather Advisory until 6 AM EST Friday for PAZ051>053-
Winter Weather Advisory until 2 AM EST Friday for PAZ024>026-
Winter Storm Warning until 4 AM EST Friday for PAZ036-056-063-
Winter Weather Advisory until 4 AM EST Friday for PAZ019-027-
Winter Storm Warning until 6 AM EST Friday for PAZ057-059-065-
Winter Weather Advisory from 5 AM Friday to 1 AM EST Saturday
Area Forecast Discussion
National Weather Service Des Moines IA
543 PM CST Thu Jan 6 2022
...Updated for the 00z Aviation Discussion...
.DISCUSSION.../Tonight through Thursday/
Issued at 204 PM CST Thu Jan 6 2022
-- Bitter cold again tonight, turning milder Saturday
-- Chillier air, gusty winds behind front Saturday night/Sunday
-- Return to milder conditions middle of next week
-- Dry forecast
Details: Shallow and thin cloud streets oriented parallel to the low
level flow exist over much of Iowa with manual adjustment to the RGB
Day Snow Fog or Day Phase Cloud Distinction making these a bit
easier to see. These clouds were able to produce some flurries/ice
crystals this morning and even this afternoon with recent reports
at ALO of HZ/5 mile visibility. Forecast challenge tonight will
be the amount of cloud cover that will move over central Iowa,
particularly northeastern Iowa/forecast area. 12z HREF/latest
National Blend of Models (NBM) shows thinning mid-level clouds
over this area with a more likely low/mid cloud deck over the
western/southwestern half of the state. Similar to previous shift,
continued to lower temperatures below initial NBM guidance to
25th percentile of available guidance with a touch of the 10th
percentile of NBM. This morning, wind chills around MCW, EST, and
AXA fell to between -33 to -38F for multiple hours. The winds
tonight fortunately will be decreasing and much lighter to start
than last night as high pressure moves over the area. Wind chills
will still drop below -30F from Winnebago to Franklin to Black
Hawk counties and northeast from mid-evening to a few hours before
sunrise. However, as winds become calm with the center of the
high, the wind chill values will have risen from their minimums by
6am. Therefore, will continue with the current advisory area and
time. The high pressure will also keep dry air in the low levels
meaning that the low level warm air advection that produces light
snow over Nebraska will move across Iowa dry.
Temperatures will begin to increase on Friday as mid-level ridging
builds into the state along with the aforementioned low level warm
air advection. This will continue and be more noticeable on Saturday
with highs in the 30s as the ridge moves off to the east. Moisture
will be drawn toward the region on breezy southerly winds ahead of a
broad trough moving across western North America. Evidence of this
moisture is seen in cross sections from the RAP and NAM with the
latter not bringing the low level saturation as far north at this
time. However, with warmer air moving over the snowpack and
dewpoints nearing freezing as well, will have to monitor for fog
potential. The trough will have a strong surface low moving across
the Canadian prairies with a cold front draped to the south to a
weaker surface low over the central Plains. This front will move
through the state Saturday evening with gusty winds developing from
the northwest and bringing a shot of chillier air. Moisture is
limited ahead of this front and while the GFS/GEFS is dry across our
area, there are enough ensemble members from the ECMWF and CMC with
light QPF over southeastern Iowa to keep the low PoPs from NBM. OTM
BUFKIT sounding Saturday evening does show that there is no ice
introduction aloft so drizzle/freezing drizzle could result before
drier air sweeps in. However, most of the precipitation will be
shunted to the east and south that this should overall not be a
concern or impact.
As the trough moves to the east on Sunday, a shortwave trough
embedded on the backside of the trough may bring light precipitation
to parts of the region Sunday night. Initial NBM is dry and think
that is still a good route based on the 6z/12z ensemble guidance
with just a few members showing light QPF somewhere in the region,
not necessarily even Iowa. Rising heights and eventually
southwesterly flow will allow milder conditions to return next week
to above normal by middle of next week.
.AVIATION.../For the 00Z TAFS through 00Z Friday evening/
Issued at 543 PM CST Thu Jan 6 2022
Widespread VFR conditions are expected during the forecast period
with winds becoming light overnight. VFR ceilings are expected
across the area on Friday with surface winds becoming southeast.
Visibilities are expected to remain unrestricted.
Wind Chill Advisory until 9 AM CST Friday for IAZ015-023-035>039-
Wind Chill Advisory until 9 AM CST Friday for IAZ004>007-016-017-
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
947 PM EST Thu Jan 6 2022
The evening update focuses on lake effect snow trends for the Thumb
shoreline, especially for Huron county where a Winter Weather
Advisory remains in effect.
Inland snow shower activity continues to fade as the near stationary
front weakens/fills during the late night. Locations north of I-69
picked up around an inch of new accumulation since noon mainly due
to persistence of the frontal zone aided by a west to east ripple of
low pressure. Mid evening radar and surface visibility support the
diminishing trend as the front and associated convergence weakens
while developing a disconnect from Lake Michigan.
Filling of the surface trough over Lower MI leads to the wind
veering more northerly over Lake Huron on a line into the Thumb
after midnight. Bulk parameters for lake convection look really good
as the fetch becomes more favorable, especially for the Huron county
shoreline. Canadian/Exeter radar illustrates more than adequate lake
instability is already in place as a broad mesovortex rides west to
east within the surface front toward Goderich. This feature is
replaced by multiple bands into Huron county as a result of the
northerly flow transition. HRRR model soundings show impressive
convective depth pushing 700 mb or near 10 kft with deep
supersaturation during the 1 AM to 4 AM time period. There are also
hints of inverted trough development over the lake in model data
across the range of resolutions that suggest a trend toward a
dominant band is possible. This could happen on the shoreline before
moving back toward mid lake or it could stay offshore and spare high
end accumulation. The evening update holds the line on Advisory
level snow accumulation in the 3-6 inch range within about 5 miles
of the shoreline between Port Austin and Harbor Beach. This allows
for accumulation during the early multi-band phase and also a
heavier burst that could materialize during the dominant band
transition. A weaker larger scale pressure gradient develops by
early morning which offers a more convincing offshore trend through
mid and late morning.
Issued at 653 PM EST Thu Jan 6 2022
A wide range of aviation conditions is in place this evening as a
cold front settles slowly southward through the region. Restrictions
are driven primarily by concentrations of snow showers fed by Lake
Michigan and focused eastward within the frontal zone. Borderline
IFR/MVFR in the MBS to FNT area is then expected to follow the front
southward toward PTK and the DTW corridor by late evening before
moving into Ohio after midnight. NW flow continues behind the front
and is favorable for some breaks in low cloud coverage toward
sunrise. A general scattered sky condition Friday morning becomes
broken VFR in the afternoon. Low level wind begins a backing trend
toward the southwest which carries some residual lake effect clouds
in from Lake Michigan Friday evening.
For DTW... VFR transitions to MVFR this evening as a cold front
moves slowly through the terminal region. IFR visibility could occur
briefly during this time in a heavier snow shower with a dusting of
accumulation. The front moves south after midnight with some breaks
in the clouds developing toward sunrise.
DTW THRESHOLD PROBABILITIES...
* High for ceiling at or below 5000 ft through tonight.
* High for snow as the precip type.
Issued at 330 PM EST Thu Jan 6 2022
A cold front positioned near the I-69 corridor will sag south
through the remainder of the area late today into this evening.
Convergence along this boundary is enhanced by the lake aggregate
trough present over the Great Lakes and this should allow for a
temporary flare up of lake effect snow showers during the late
afternoon and early evening as this front releases south.
Given current low level trajectories as gleaned from regional radar
and visible satellite imagery early this afternoon, expect the most
concentrated snow shower activity to focus from around I-69 south to
M-59 with activity dissipating with time into the evening as it
shifts south into the I-94 corridor. Powdery accumulations will be
limited to half an inch or less in general, especially M-59 north,
with perhaps an inch in localized spots.
Lake effect snow shower activity over the Thumb has shifted east
during the day, but expect banding to pivot back onshore later this
afternoon and especially this evening as low level flow swings
abruptly to the north by 00z. Inversion depths are forecast by 3km-
NAM to be on the order of 6-7kft with most of this layer within the
dendritic growth region, so snow shower intensity should support the
continuation of the advisory for Huron County. The main question will
be how long any activity that does develop remains onshore tonight.
Confidence in the duration of snowfall is too low to consider an
upgrade to a warning at this time. Additional snowfall tonight looks
to maximize along the immediate Lake Huron shoreline from Port
Austin to Harbor Beach where an "uncertain" 3 to 5 inches of snow
Cold conditions will persist into Friday with lake effect activity
diminishing and pivoting east of the area. Temperatures will range
in the upper teens to lower 20s. A brief moderation in temperatures
will then occur from late Saturday into early Sunday as a shortwave
ridge builds into the region between the exiting upper trough now
working through the area and then next stream of Pacific shortwave
energy. Expect temperatures to climb into the lower 30s during this
time frame with a chance of light snow showers as this shortwave
crosses the area.
Northerly winds gusting to around 20 knots across Lake Huron is
promoting elevated wave heights leading to hazardous small craft
conditions. A Small Craft Advisory remains in effect across the
nearshores from Outer Saginaw Bay to Port Huron into early tomorrow
morning. Winds turn more northwesterly by tomorrow. This wind
direction will continue to favor some elevated wave heights across
northern portions of the Thumb through tomorrow afternoon though
wind gust potential is expected to remain mostly under 20 knots. On
Saturday, pressure gradient increases across the central Great Lakes
between an Appalachian high pressure and a low pressure system moving
from western Ontario into the Hudson Bay. This will lead to
increasing southerly flow and the potential for gales across
portions of Lake Huron. Frontal boundary is driven through the
region early Sunday leading to winds out of the west that will
have potential to gust to around 30 knots.
MI...Winter Weather Advisory until 7 AM EST Friday for MIZ049.
Lake Huron...Small Craft Advisory until 4 PM EST Friday for LHZ421-441>443.
Gale Watch from Saturday morning through Saturday evening for
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
You can obtain your latest National Weather Service forecasts online
Area Forecast Discussion
National Weather Service Northern Indiana
857 PM EST Thu Jan 6 2022
Issued at 836 PM EST Thu Jan 6 2022
Moderate to heavy lake effect snow will continue for portions of
far southwest Lower Michigan and far northwest Indiana through
Friday morning before rapidly diminishing in the afternoon. 5 to
10 inches is likely in these locations with locally higher amounts
over a foot in northern Berrien county. Light snow showers or
flurries are expected elsewhere. It will be cold, with wind chill
values of zero to ten below tonight. A wintry mix is possible
Saturday night into Sunday morning.
Issued at 836 PM EST Thu Jan 6 2022
Our moderate to heavy lake effect snow band has arrived, just
sinking southward into the northern portions Berrien/Cass
Counties in Michigan as of this writing. Issued an SPS to
highlight this band for the two counties, with 1-2 inch per hour
rates and visibilities of 1/2 mile or less expected. Accidents and
poor road conditions have been reported thanks to the
falling/blowing/drifting snow. One video submitted to our Twitter
account from near South Haven looked like we had front row seats
on the Millennium Falcon riding through space-so that should give
everyone an idea of how driving in this stuff will be (not
As for forecast changes haven`t made any significant updates.
Still opting to keep the current headlines as they are given the
persistent trend in model guidance to keep the band further
eastward/north-which is in line with the current observations. It
seems the eastward extent to the band is pretty limited/light as
far as impacts go (as of this writing), so no plans to expand
eastward into Lagrange county or upgrade any of the advisories
yet. However, will continue to monitor trends in the event things
get more aggressive when the broader trough arrives.
Reports of snow fall and road/visibility conditions are
appreciated. Thank you to those who have submitted them thus far.
.SHORT TERM...(Tonight and Friday)
Issued at 242 PM EST Thu Jan 6 2022
Challenging lake effect event the big problem this aftn. As
addressed yesterday, intense lake effect snow found through central
MI along sfc trough under upper low through cntrl lower MI. This
curves n/nw into dominant single band mid lake west of Ludington and
the feature to watch going into this evening. Sfc trough, currently
along a GRR to DTX line, will break down quickly late aftn as parent
upper low finally opens/kicks east through lake Huron. As that
occurs, upstream lake band should intensify significantly as large
scale lake aggregate thermal troughing takes over. This intense band
expected into sw MI this evening and hold near steady state into
Friday morning before eventually lifting out in the aftn. Some
typical e-w waver implied in most model guidance and expected given
modulating background/intense thermal trough. While far wwd
solutions like HRRR can not be ignored given how warm lake sst are,
hedged east given greater multi-model concensus. Heaviest potential
accumulations likely invof nrn Berrien and adjacent Van Buren/Cass
where isold 15" amounts look quite plausible especially in light of
model derived 1-2"/hr snowfall rates at peak intensity. 5 to 10
generally expected otherwise in the warning, and up to 5 in
surrounding advisory counties, perhaps a bit more in far northern St
Joseph but weakening cloud bearing flow should stall srn extend/feed
of heavier accums there. Will keep as is with prior headlines.
Cold otherwise inland with diminishing gradient of which will keep
wind chills aoa -10 late tonight/Fri morning.
.LONG TERM...(Saturday through Wednesday)
Issued at 242 PM EST Thu Jan 6 2022
Intense warm advection develops late Fri night as arctic ridge
breaksdown in response to incoming large scale upper trough.
Sufficient moisture advection looks to hold off until evening before
activating precipitation but fair amount of timing spread exists yet
in 12Z guidance. Nevertheless warming aloft along with sfc temps
around freezing and cold ground temps likely to lead to a skating
rink on area roads and which may not necessarily improve Sun morning
as cold air poised to wrap in quickly. Thus given colder 12Z
consensus solution added a bit more ice again.
Another arctic ridge quickly follows though the wrn lakes Mon with
another round of lake effect by late day into Tue yet shifts ewd
ahead of another system digging through James Bay Wed.
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 638 PM EST Thu Jan 6 2022
Expect predominantly MVFR to IFR conditions at KSBN tonight, and
VFR to MVFR conditions at KFWA. Expect westerly winds at KFWA with
light snow showers diminishing to maybe flurries (if anything)
overnight. Expect mid-high end MVFR ceilings improving to VFR.
Otherwise, the main focus this issuance is how much will KSBN be
impacted the ongoing lake effect event. An intense band of snow
north of South Haven, MI as of this writing will gradually shift
southward through the evening, with 1-2 inch per hour snow rates
and blowing/drifting snow thanks to blustery W-NW Winds behind an
incoming trough. A majority of the guidance keeps this heavier
band north of KSBN (barely), but it`s possible that KSBN is
impacted. For now went more conservative with ceilings and
visibilities based on observations from the site today, but expect
the worst conditions between 6-10z ish if the band does impact
the site. It is also possible the band stays further north, in
which case conditions would be better than forecast.
IN...Winter Weather Advisory until 10 AM EST Friday for INZ004-005.
MI...Winter Storm Warning until 10 AM EST Friday for MIZ077-078.
Winter Weather Advisory until 10 AM EST Friday for MIZ079.
LM...Small Craft Advisory until 4 PM EST Friday for LMZ043-046.
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Area Forecast Discussion
National Weather Service New Orleans LA
657 PM CST Thu Jan 6 2022
Main focus on this evening update was paying close attention to
the frontal position and its forward progression, ingesting high-
res short-range guidance to match obs trends. Utilized the recent
22Z HRRR for temperatures and dewpoints through tonight, as well
as a blend of the HRRR and 90th percentile NBM for surface
winds/wind gusts. Some low clouds are spreading in behind the
front per latest GOES-16 Night Fog Channel Diff, with ceilings
around 1 to 1.5kft AGL, generally aligned with the 925mb front.
Approached MinT`s carefully given persistent CAA through the
morning hours, as well as areas of low-clouds spreading southeast
reducing radiational cooling potential. Guidance does reduce
gradient winds somewhat towards daybreak, but not completely
enough which will allow mixing to persist. With all that said,
aimed near or just slightly above deterministic NBM to account for
these processes and their interaction with temperature trends.
Additionally, removed the mention of frost as well, but can`t rule
out some light areas for a few hours across SW MS or the Pearl
River Basin, east to the MS coast within any protected areas.
Clouds will try to break up during the morning hours, but will
likely continue to see cold air stratocumulus clouds lingering
over marine areas. Temperatures look on track glancing at latest
guidance/trends, leading to a chilly winter-like day ahead for
everyone as we close out the week. KLG
PREV DISCUSSION... /issued 357 PM CST Thu Jan 6 2022/
SHORT TERM (Tonight through Tuesday)...
A band of showers continues to move across the area as the cold
front moves through the area. Although we have a little moisture
advecting into the area as well as the frontal passage moving
through, we still lack a lot of the necessary instability needed
to produce actual thunderstorms. With this in mind, mainly just
showers are expected to continue through early evening tonight.
Updated the POPs and Wx grids for the current and next few hours
to reflect the showers and removed the threat of lightning and
thunderstorms as we have not seen any so far and confidence is low
that we will see any lightning develop over the next several
hours. Cooler air will penetrate the area behind the front causing
temperatures to drop well below climo to near and below freezing
in most areas with lows tonight/ Friday morning in the low 30s.
Daytime temperatures will see an almost 20 degree difference from
today`s temps and are expected to be chilly with highs barely
reaching mid 50s. Friday night temperatures will be chilly once
again with lows in the upper 40s to low 30s. Winds look to really
lighten up Friday night so wouldn`t be surprised if temperatures
drop more closer to freezing with the help of continued strong
CAA. Otherwise, no weather expected on Friday.
Saturday temperatures will see an increase with highs in the low
70s/ upper 60s as the ridge shifts starts to build in warmer air
is advected into the area. A slight repeat of fronts is expected
Saturday night as a cold front is forecast to move through the
area some time Saturday evening. The only difference with this
front is the substantial moisture and dynamic force return
allowing for increased chances of rainfall across the CWA on
Sunday and development of one or two thunderstorms. Persisting warm
air advection will allow for seasonably warm temperatures to
continue through the day with highs in the mid/upper 70s Sunday
but will be overcame by cooler air mass. /TDB/
LONG TERM (Sunday night and beyond)...
A cooler and more dry air mass will be the driving factor as winds
begin to shift and become more northerly through the night on Sunday
as a result of strong cold air advecting into the region. As a
surface high ridges into the area Monday, any lingering s/ts will
move east and out of the area by daybreak and increasing clearer
skies and cooler temperatures will be expected.
Monday night/Tuesday morning expect near freezing temperatures with
low temperatures dropping 10 degrees or more from the night before
as lows dip down into the mid to low 30s. Light NE winds are
forecast Tuesday with mostly clear skies and drier weather
conditions. Tuesday night will be another chilly night with lows
dipping into the low to mid 30s yet again. Upper level high pressure
will remain in place through at least mid week so drier conditions
are expected to continue. /TDB/
AVIATION (00Z TAF DISCUSSION)...
Focus for this evening and tonight will be a frontal boundary
passing through the entire area followed by increasing surface
winds and direction change bearing 330 to 350 (NNW), transitioning
to 350 to 010 (N) through the late evening/overnight hours. Winds
remain elevated through tonight and into early tomorrow. Other
impacts include low CIGs building in behind the front ranging 1 to
1.5kft already passing KBTR to KMCB, spreading southeast.
Included approximate timing for all terminals ahead of the low
clouds in area TAFs tonight, with prevailing MVFR to intermittent
IFR conditions into daybreak. Expect a steady transition to VFR
for all terminals through mid to late morning from north to south
as low clouds dissipate, with occasionally breezy north winds
persisting through the day, transitioning to 050 to 070 (NE) in
the afternoon hours. KLG
North winds near 15 to 20 kts continue and are forecast to shift
more easterly tonight near 25kts as the cold front moves into the
coastal waters. A Small Craft Advisory is in effect for tonight
through tomorrow afternoon to account for these windy conditions.
Going into the weekend, expect another front to enter the coastal
water bringing similar SCY conditions to today`s expected late
Saturday through Sunday. Additional headlines after the current
one may be needed for the next round of windy conditions this
.PRELIMINARY POINT TEMPS/POPS...
MCB 31 53 38 69 / 0 0 0 20
BTR 34 55 43 70 / 0 0 0 40
ASD 35 58 41 71 / 0 0 0 30
MSY 42 55 49 71 / 0 0 0 40
GPT 36 55 43 67 / 0 0 0 10
PQL 34 55 40 68 / 10 0 0 10
GM...Small Craft Advisory until noon CST Friday for GMZ530-532-534-
GM...Small Craft Advisory until noon CST Friday for GMZ532-534-536-
Area Forecast Discussion
National Weather Service Marquette MI
914 PM EST Thu Jan 6 2022
Issued at 913 PM EST THU JAN 6 2022
Per hourly HRRR trends and latest model runs, will trend snow
amounts up an inch over snow belt regions prone to NNE flow. Bands
could briefly become heavy at times as convergent areas move up the
Keweenaw early tonight and over eastern portions of Marquette
County. This would potentially push localized totals up into the 8-
10" range over those snow belts. Currently, radar mosaic continues
to show persistent LES bands with temperatures ranging from the
single digits over the interior west to teens over the remainder
of the UP. Updated grids have been sent.
.SHORT TERM...(This evening through Friday)
Issued at 351 PM EST THU JAN 6 2022
Precip has transitioned over to pure LES within the NNE to N wind
belt regions. The bands are stretching fairly far inland, although
do lighten up beyond the initial upsloping enhancements. This
trend will continue well into the overnight period, with
indications of localized heavy bands setting up within convergent
areas, such as near the Porkies as well as within the eastern
portions of Marquette County. Orographic lift will assist in
bumping up snow amounts within the higher terrain, especially
wherever the heaviest bands set up. Again though, the focus
shouldn`t be on amounts so much as it should be on impacts. Even
though the amounts will be much lighter overall as compared to the
last 24 to 48 hours, adding more snow onto already snow-covered
roads will cause hazardous driving conditions in addition to
reduced visbys within moderate to heavy bands.
The other weather-related concern for tonight will be the incoming
frigid temperatures expected. Wind chills tonight will easily be
sub-zero for much of the U.P., especially in the interior west.
The limiting factors will be whatever LES-related cloud cover that
persists overnight as well as the general/typical moderation
provided by Lake Superior. The winds themselves look to generally
remain near/below 10 knots overnight. Actual low temps will drop
into the negative teens in the far west, sub-zero interior west,
low teens above zero along Lake Superior, and single digits
elsewhere. In other words, quite a bit of variation in lows is
expected depending on the location, but with the overall picture
of coldest temps in the west/interior. Highs tomorrow will be
fairly reminiscent of today, topping out in the teens for most,
perhaps only single digits in the far west, and around the 20
degree mark near and along lakeshores.
.LONG TERM...(Friday night through Thursday)
Issued at 310 PM EST THU JAN 6 2022
Overall, the long-term pattern will be cooler than normal leading to
LES (primarily for NW wind snow belts) and drier than normal weather
elsewhere. A warm front brings a chance of light snow and warmer
temps on Saturday ahead of an arctic cold front Saturday night.
Temperatures fall through the day on Sunday and Sunday evening
through Tuesday morning look particularly cold with widespread below
zero temps likely, especially during the morning hours. Bitter cold
combined with 10-15 mph winds should result in dangerous wind
chills, especially Monday morning. A clipper system could
invigorate LES on Tuesday and perhaps bring light snow to inland
locations too, but this seems less likely than it did yesterday.
Otherwise, a trend toward warmer and drier than normal weather
appears likely going into the second half of next week.
Starting at 00z Saturday, low temperatures could occur early in the
night until WAA brings clouds and increasing southerly winds in well
before sunrise. Southerly winds become gusty by Saturday morning,
especially for portions of the Lake Superior shoreline favored by
downsloping winds. WAA forces light snow showers on Saturday, but
most locations pick up less than an inch or two. Lake effect snow
seems like a good bet for south to southwest winds snow belts off
Lake MI on Saturday. Lake-850 mb delta-Ts around 18 to 20C supports
generally moderate LES potential, especially considering LES is
expected to be transient as WAA continues during the day on
Saturday. Other than the snow chances above, Saturday appears to be
the warmest day of the next week with temperatures warming to near
or above 20F across the entire UP.
The warm-up is brief since the next arctic cold front quickly pushes
east across our CWA Saturday night between ~06z and ~12z Sunday.
Thus, Saturday night into Sunday also follows a non-diurnal
temperature curve with max temps likely to occur before sunrise on
Sunday. Temps then fall into the single digits and teens by Sunday
afternoon with below zero wind chills across the CWA by Sunday
afternoon. Breezy winds continue through Monday as temperatures fall
below zero resulting in potentially dangerous wind chills,
especially Monday morning. The coldest temperatures of this arctic
blast seem likely Monday night when winds diminish and some breaks
in the cloud cover are possible. If light winds and clear skies
materialize then readings colder than -20F are possible across the
interior west on Tuesday morning.
Considerable uncertainty remains for Tuesday and beyond as a series
of low-amplitude shortwaves dive southeast across the CWA. The
clipper previously slated for Tuesday could still occur, but 12z
model guidance suggests it may track across Ontario instead. There
is decent agreement amongst the various models for a rapid warm up
to above normal temperatures by Wednesday thanks to downslope flow
off the Rocky Mountains.
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 658 PM EST THU JAN 6 2022
Conditions continue to be the worst at KIWD at this time where LIFR
will be the predominant flight category into tonight. Elsewhere,
expect fluctuation between IFR and MVFR as lake effect snow persists
into tomorrow in the NNE flow. Winds though will fortunately only
be in the 5 to 10 kt range through the TAF period, eventually
backing to the WSW tomorrow afternoon. A return to VFR levels is
probable by tomorrow afternoon.
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 407 PM EST THU JAN 6 2022
Winds on Lake Superior stay below 20 knots tonight through Friday.
Next gale event looks to get going with southerly gales to 45 knots
Friday night into Saturday, mainly east half. Northwest gales to 40
knots develop Sat night and continue into Sunday night. Freezing
spray continues to be an issue for most of this forecast with the
stronger wind and cold temperatures especially starting on Saturday
night. Cold temperatures and gusty winds persist through Tuesday
Winter Weather Advisory until 6 AM EST Friday for MIZ004-005.
Winter Weather Advisory until 9 AM EST /8 AM CST/ Friday for
Gale Watch from late Friday night through Saturday evening for
Gale Watch from late Friday night through Saturday evening for
Area Forecast Discussion
National Weather Service Mount Holly NJ
954 PM EST Thu Jan 6 2022
Low pressure over the Southeast will lift to the northeast
towards the Mid-Atlantic tonight, then intensifies east of New
Jersey on Friday before departing. High pressure builds in from
the west Friday night and moves offshore Saturday night. A front
approaches on Sunday and crosses the region Sunday night,
followed by an Arctic front Monday night. Arctic high pressure
builds into the region Tuesday, then departs on Wednesday.
Another front passes north of the region Thursday.
.NEAR TERM /THROUGH FRIDAY NIGHT/...
A burst of light snow has passed through the western suburbs of
Philadelphia and Berks county, and is moving through the Lehigh
Valley. Will not make significant changes to the forecast with
this update, as a coating or so has fallen from this. But it
will bear watching. HRRR continues to indicate heaviest snow
across much of New Jersey.
Otherwise, the main focus for this period continues to be low
pressure system expected to bring snow tonight into early
Friday. The forecast guidance is now in good agreement tracking
low pressure over the SE US north and east off the N.C coast to
a position south of Cape Cod by 12z Friday.
Going through the overnight is when things get interesting.
Clouds thicken through this evening with precipitation
overspreading the area SW to NE late this evening into the
overnight (mainly after 10 PM or so) as the deepening low
pressure system tracks up the coast. This will be a mostly snow
event except over southern DE and south coastal NJ where we
still think there will be sleet and rain mixing in at times,
especially at the onset. This will keep amounts lower here. The
main change with this update is that we`ve issued a Winter Storm
Warning for most of central and southern NJ as confidence has
grown that there will be swath of higher snowfall amounts here,
with upwards of around 6 inches or so under a heavier band
setting up. Challenge is that these higher amounts probably
won`t even include these entire counties as the axis of heaviest
snow will likely be just south of the Turnpike but away from
the coast extending roughly from Cumberland Counties NE through
Monmouth Counties. Strictly speaking, this will be a marginal
event in terms of reaching Winter Winter Storm Warning criteria
but given the timing leading up to and into the morning rush,
impacts could be high. Also, since it will be fast moving, most
of the snow will be falling within just a few hours with rates
potentially reaching 1-2 inches per hours. Farther north over
eastern PA and over most of Delmarva we are still forecasting a
general 2 to 4 inches of snow.
Heading into Friday the snow will quickly wind down from west to
east through the mid morning as the deepening low races NE with
sunshine even developing by afternoon. However in the system`s wake
winds will strengthen out of the NW with gusts of 20 to 30+ mph
expected by afternoon. This may cause some issues with blowing snow
though it should be noted that the strongest winds will be near the
coast where it will be a wetter snow. Lows tonight will be in the
20s to low 30s and these temps won`t increase too much for Friday
due to the NW winds / cold advection behind the low. Highs will be
mostly in the upper 20s to mid 30s...coldest north and mildest
For Friday night, winds gradually diminish due to relaxing pressure
gradient as the low moves away and high pressure starts to build
towards the region. It will be a very cold night though with lows
mostly in the teens. Saturday will then be dry and cold as the high
crests over the area.
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
High pressure centered over West Virginia and Virginia on
Saturday will gradually slide east through the day, and will be
off the Virginia/North Carolina coast by Saturday evening. High
pressure continues to track offshore Saturday night, and return
flow sets up behind the departing high.
Sunny and cold on Saturday with highs in the upper 20s to low
30s. These highs are around 10 degrees below normal.
A cold front approaches Saturday night. Clouds increase after
midnight. Prior to midnight, however, with clear skies and light
southerly winds, expecting strong radiational cooling
conditions. Low temperatures will drop into the teens and 20s in
the evening, and then temperatures will hold steady and slowly
rise through the night as those clouds spread east. Based on
latest models trends, precip should hold off until after
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Warm air advection aloft will be underway on Sunday as southerly
flow increases between an approaching cold front and high
pressure offshore. Light precip develops in the morning over the
far western zones. Surface temperatures will remain below
freezing through the morning, but temperatures above 950 mb will
warm to +5C. As a result, there is a chance for a prolonged
period of freezing rain Friday morning for areas west of the
Delaware River, generally in the southern Poconos, Lehigh
Valley, and down into the Delaware Valley. Temperatures in
Philadelphia proper and areas east should be above freezing by
the time rain arrives, and then temperatures warm to above
freezing for all but the southern Poconos by Sunday afternoon.
Based on forecast QPF, generally expecting up to 1/10 inch of
ice accretion. Highs on Sunday will range from the low 30s in
the southern Poconos to the mid and upper 30s otherwise north
and west of the Fall Line, and in the low to mid 40s south and
east of the Fall Line. Southern Delmarva will get into the mid
and upper 40s.
Cold front works its way through the region Sunday night and
precip tapers off from northwest to southeast. A bit more wintry
weather is possible as it winds down.
A stronger Arctic cold front then passes through the region
Monday afternoon. Models indicating strong Lake Effect Snow well
north and west of the local forecast area, but if the trajectory
is good enough, it is possible for some streamers to make it to
the far northern zones.
Behind that front, the coldest air of the season will spread
into the region. Lows Monday night will drop into the single
digits and teens, and then highs on Tuesday will be in the teens
and low 20s. Will undercut NBM max Temps on Tuesday by several
degrees as it looks to be quite cold.
This cold snap will be brief, as the Arctic high slides offshore
Tuesday night and Wednesday, and return flow ushers a milder air
mass into the region. Temps rebound by 10-15 degrees on
Wednesday, and then closer to normal levels on Thursday.
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
Tonight...VFR initially, then CIGs lower to MVFR by 06Z/07Z,
then quickly lower to IFR thereafter. IFR VSBYs in light to
moderate snow with occasional LIFR conditions. Light NW winds,
becoming N around 10 kt. Moderate confidence overall. Snow at
PHL 4-5 inches expected.
Friday...IFR/LIFR CIGS/VSBYS in the 12Z to 15Z time period in
snow, then rapid improvement from SW to NE thru the midday. NW
winds 15-20 kt with 20-30 kt gusts in the afternoon, which may
produce some BLSN that was included with the latest TAFS.
Outside of any VSBY restrictions for BLSN, VFR expected thru the
afternoon. Moderate confidence.
Saturday through Saturday night...VFR. Light N winds Saturday,
then light S winds Saturday night. Moderate confidence.
Sunday through Sunday night...Sub-VFR. FZRA at KRDG/KABE and
possibly KTTN Sunday morning and RA elsewhere. Precip changes to
plain RA in the afternoon. A brief period of wintry weather is
possible Sunday evening as precip winds down. Conditions improve
to VFR Sunday night. S winds 5-10 kt, becoming NW late Sunday
night. Low confidence.
Monday...VFR. NW winds 10-15 kt with gusts to 20 kt. Moderate
Tuesday...VFR. NW winds 5-10 kt. Moderate confidence.
Winds over our northern zones diminish into early this evening
but then winds ramp again late tonight associated with the
coastal low. Gale conditions are expected on most of the waters
beginning Friday morning. The upper Delaware Bay should stay
below gale force, but gusts to 30 kt are expected there. Windy
conditions will continue through the day Friday then diminish
Saturday through Saturday night...Lingering SCA conditions in
the morning, then sub-SCA conditions.
Sunday through Monday...SW winds increase to 15-20 kt with
gusts up to 25 kt. Winds shift to the NW Monday morning. Seas
build to 3-5 feet. A SCA will likely be needed.
Tuesday...NW winds 15-20 kt with 25-30 kt gusts. A SCA will
likely be needed.
PA...Winter Weather Advisory until 10 AM EST Friday for PAZ054-055-
NJ...Winter Weather Advisory until 10 AM EST Friday for NJZ001-
Winter Storm Warning until 10 AM EST Friday for NJZ013-014-
DE...Winter Weather Advisory until 10 AM EST Friday for DEZ001>003.
MD...Winter Weather Advisory until 10 AM EST Friday for MDZ012-015-
MARINE...Gale Warning from 6 AM to 10 PM EST Friday for ANZ431-450>455.
Small Craft Advisory from 4 AM to 10 PM EST Friday for ANZ430.