Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/08/22
Area Forecast Discussion
National Weather Service Cleveland OH
946 PM EST Mon Feb 7 2022
High pressure will build north over the area by Tuesday
afternoon. Another low pressure system pulls a warm front
across the area Tuesday night into Wednesday followed quickly
by a cold front Wednesday. A surface trough then lingers
through Thursday before the next low pressure system deepens
over the Great Lakes Friday.
.NEAR TERM /THROUGH TUESDAY NIGHT/...
Only made changes to hourly temperatures and sky cover to
reflect current trends. A few flurries still occurring. Will
continue to watch for the development of weak lake effect snow
showers in the wake of the 850mb trough.
The cold front is currently moving into far eastern Ohio and
western PA with decent pressure rises noted behind the front.
METAR observations show a sharp wind shift to west to west-
southwest behind the boundary with temps falling through the low
30s. A mid/upper shortwave trough and associated vort max is
moving through lower Michigan and increasing low- level moisture
and lift from west to east. This is reflected by snow showers
and lake-effect snow bands expanding across Michigan this
afternoon in the cold air advection. Once this better low-level
moisture dives across Lake Erie early this evening, lift from
the shortwave passage will generate scattered rain/snow showers
across far NE Ohio and NW PA. HREF members continue to support
this light precip, so continued with slight chance to chance
PoPs in this area this evening, although dialed them back a bit
given the drier conditions at the onset.
The true cold air arrives tonight behind the mid/upper shortwave
with strong cold air advection dropping 850 mb temps to -11 to -13 C
by 12Z Tuesday and around -15 C by mid morning behind the passage of
a second shortwave and vort max. This combined with a 270 flow will
support bands of lake-effect snow east of Cleveland along the I-90
corridor through Erie County PA, as well as northern Crawford County
at times. The latest NAM and RAP BUFKIT forecast soundings show
inversion levels rising to a marginal 5 to 6 thousand feet after
Midnight tonight but lots of moisture through that level and into
the DGZ, but the greatest lift (Omega) tends to stay near the bottom
of the DGZ. There is also quite a bit of wind shear through the
boundary layer which may inhibit the development of a single west-
east band leading to more disorganized snow showers moving west-
east. Plenty of open water developed the past 2 days due to the ice
floes, so given the aforementioned moisture and at least 150-200
joules of lake induced CAPE, feel that lake-effect snow coverage
will be decent. However, the negative factors discussed above will
certainly limit the organization and efficiency, so kept
accumulations across the primary snowbelt in the 0.5 to 1 inch
range with 1-2 inches (locally higher) in NW PA. Parts of Erie
County could see 4 inches of snow, but not confident enough to
put that in official forecast products.
Mid/upper shortwave ridging will build across the Ohio Valley
Tuesday afternoon with surface high pressure sliding through the
Appalachians. Flow backing southwesterly and decreasing moisture and
a lowering inversion will push weakening lake-effect bands up the
shoreline into western New York during the afternoon. Expect peaks
of sunshine to spread in from west to east. Arctic air remaining in
place will keep highs in the upper 20s to near 30 with mid 20s in NW
PA. The axis of the shortwave ridge will slide east Tuesday night
with the surface high moving into the Mid Atlantic as well ahead of
the next incoming mid/upper trough. This will set up warm air
advection, so early night lows in the mid 20s will rise into the low
30s by Wednesday morning. Brought in slight chance Pops for light
snow showers toward Wednesday morning as forcing and moisture
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
An upper-level trough will move across the area Wednesday, providing
synoptic lift for precipitation to the area. Return flow associated
with the warm sector of the associated low moving into the northern
Great Lakes region on Wednesday will allow for warm air advection to
bring temperatures back to the upper 30s to even low 40s for some
locations Wednesday afternoon. This will cause precipitation to fall
as a rain/snow mix Wednesday with some areas even experiencing
periods of all rain. The weak cold front associated with the low
moves across the area Wednesday evening, causing temperatures to
drop back below freezing with low near 30 Wednesday night. System
precipitation becomes primarily lake effect Wednesday night, and
with the temperature drop, precipitation type should become all snow
once again. Lake effect snow continues into Thursday and potentially
into Thursday night. Total QPF Wednesday and Wednesday is generally
expected to be 0.01 to 0.15", so despite decent melting conditions
with dew points in the upper 30s and a moderate southerly wind,
there shouldn`t be any flooding concerns. Total snowfall with the
lake effect snow Wednesday night into Thursday should be around 2"
or less, mainly for the snowbelt.
.LONG TERM /FRIDAY THROUGH MONDAY/...
Clipper system moves across the Great Lakes region Friday and Friday
night. Similar to the Wednesday system, return flow will allow
temperatures to rise into the upper 30s to low 40s, allowing for a
rain/snow mix and even periods of all rain. Colder temperatures move
in for the weekend, allowing for lake effect snow to develop Friday
night through Saturday night. Coldest temperatures are expected
Saturday night through Sunday night when well below normal
temperatures are expected. Wind chills near zero will be possible
Sunday morning and Monday morning.
.AVIATION /00Z Tuesday THROUGH Saturday/...
MVFR ceilings spreading west to east across the region generally
near and in the wake of an 850mb trough. As this boundary moves
eastward expect the MVFR ceilings to advance into western PA by
02-03Z. There could be a few flurries across the region but the
main area of snow showers will be across NE OH into NW PA. This
is where some lake effect snow showers should develop. The only
terminal that could see brief IFR conditions with heavier snow
showers looks to be KERI. IF this occurs it would be 08Z-12Z.
Winds remain westerly through mid morning with speeds 8 to 14
knots with gusts to 20 knots possible. The strongest winds
should be along the lakeshore. Winds shift to the southwest and
south at 8-12 knots through Tuesday afternoon.
Outlook...Non-VFR is possible in rain or snow showers
Wednesday into Thursday then again Friday into Saturday.
South to southwest winds will persist through much of the week as
high pressure builds in and a warm front crosses the lake, causing
more southerly winds through Wednesday. Low pressure and a cold
front Wednesday into Thursday causing winds to become southwest.
Overall, offshore flow will help keep ice away from the Ohio
shoreline and some ice could be pushed towards PA during westerly
Area Forecast Discussion
National Weather Service Green Bay WI
549 PM CST Mon Feb 7 2022
Updated aviation portion for 00Z TAF issuance
.SHORT TERM...Tonight and Tuesday
Issued at 238 PM CST Mon Feb 7 2022
The latest RAP analysis and satellite/radar imagery show low
stratus has eroded over northeast Wisconsin early this afternoon.
Meanwhile, another swath of stratus along the leading edge of
warm advection is slowing moving southeast over the northern
Mississippi Valley. MVFR ceilings and light snow/flurries are
occurring over northern Minnesota within this warm advection
regime. Forecast concerns mainly revolve around light snow chances
and cloud/temp trends over the next 24 hours.
Tonight...Weak surface ridge axis will be moving across the region
during the evening. However, the zone of warm advection will be
advancing across Wisconsin at the same time, which will return
overcast conditions to the region from northwest to southeast.
Deep saturation will be difficult to achieve in this warm
advection zone, but upstream obs and forecast soundings suggest
saturation up to 700 mb may be enough for light snow/flurries,
particularly over north-central WI. Expanded the small chance this
evening. Saturation doesn`t look quite as robust over northeast
WI so think light snow chances could diminish before reaching that
part of the state. Due to the cloud cover, raised low temps a
Tuesday...Most clouds will have exited northeast WI by the start
of Tuesday morning, so think will see a lengthy period of
sunshine. But should see clouds increase again in the afternoon
ahead of the next in the seemingly endless series of clippers.
Chances of snow should hold off until Tuesday night. With a breezy
south wind, temps will warm into the upper 20s to mid 30s.
.LONG TERM...Tuesday Night Through Monday
Issued at 238 PM CST Mon Feb 7 2022
A Clipper system staying north of lake Superior will bring
some light snow showers Tuesday night into Wednesday. Some freezing
drizzle is possible in East Central Wisconsin late Tuesday night. A
dusting to half inch seems likely with the highest amounts in North
Central Wisconsin. Temperatures will be relatively mild.
Cooler temperatures are expected Wednesday night and Thursday behind
the Clipper system. Northwest winds blowing across Lake Superior
should produce lake effect snow showers in Vilas county. AMounts
should be an inch or so.
A strong Clipper system will bring a better chance of snow to the
entire area Thursday night into Friday. One to three inches are
expected with the highest amounts in the north. Mild temperatures
Friday will be followed by colder weather for Saturday and Sunday
as some arctic air returns to the region.
.AVIATION...for 00Z TAF Issuance
Issued at 543 PM CST Mon Feb 7 2022
Clouds were overspreading the region early this evening, with
3000-4000 ft ceilings moving into the western part of the forecast
area. The ceilings may briefly lower to MVFR at the western TAF
sites later this evening. An upper level disturbance may also
produce scattered very light snow showers or flurries at RHI for
a brief period this evening. Clearing skies are expected overnight,
but more clouds will arrive Tuesday afternoon, with a threat of
MVFR ceilings returning at RHI/AUW/CWA late in the afternoon.
A brief period of LLWS is possible at each of the TAF sites from
mid-morning through mid-afternoon Tuesday. Surface winds will
also become a bit gusty during the day.
Area Forecast Discussion...UPDATED
National Weather Service Chicago/Romeoville, IL
913 PM CST Mon Feb 7 2022
Issued at 913 PM CST Mon Feb 7 2022
For this evening`s update, focus was on fog/low cloud potential
into Tuesday morning and how that will play into Tuesday highs as
noted in today`s Short Term AFD. In summary, the signal for low
clouds and fog on Tuesday looks less of a chance than it had
earlier, so have adjusted some to account for that, including
bumping up Tuesday highs a couple/few degrees.
Surface ridging extends northward up the Illinois/Indiana
stateline as of 9 PM and is gradually shifting southeast. While
temperatures dropped quickly south of the Chicago metro under this
ridging early this evening, the dew points also did, indicating
any sublimation from today was limited enough that the moisture
was only in a static layer. So radiation fog in our southern CWA
is seeming more unlikely, especially as solid mid cloud is
spreading southeast. This mid cloud will spread over most of the
area with high confidence. The RAP 800 mb RH was used as a proxy
as it has a fair handle on this. With this cloud likely to persist
for the overnight after it moves in, lows will be milder and have
nudged those up a few degrees in the north. As low-level warm
advection ensues off the deck, the cooling of the boundary layer
now looks to be insufficient enough to result in much of a low
cloud/fog footprint in northern Illinois. Do think there could be
some to develop in southeast Iowa/northeast Missouri/western
Illinois where the surface dew point nose of 20-25 is. If that
were to develop, that would expand in after daybreak. But this
seems like more of an outlier solution with observational trends
as well as guidance trends, with even the more moist NAM having
backed off with its 00Z solution.
For highs on Tuesday, the midnight shift will assess in full, but
did have enough confidence to nudge them up 2-3F degrees, and that
may not enough. This nudge up was due to a milder starting point
expected, less likelihood in widespread low clouds in the
morning, and looking back at climatology. On that last point, with
925 mb temperatures of +5 to +7, such as forecast in the northern
CWA from a model blend, this shows an average of mid 40s for
Chicago for early February with snow cover. Did not go that mild
yet, but mid 40s are plausible, especially over the less snow
covered areas of far northern Illinois (Dixon to Rockford to
Harvard). Again, midnight shift will evaluate if values need to be
nudged warmer area-wide, and will have more observational trends
for any low cloud potential into the morning.
Issued at 124 PM CST Mon Feb 7 2022
Currently, a 1016mb surface low pressure system is located over Lake
Huron beneath broad upper-level cyclonic flow. Meanwhile, a surface
ridge extends from a surface high pressure system in central Texas
from the Ozarks to eastern Iowa. We find ourselves between both
surface features this afternoon in a cold-advection regime with
northwesterly winds and flurry-producing stratocumulus clouds. As
the surface ridge slides southeastward tonight, clouds will clear
and winds will gradually slacken while turning southwesterly. Lows
overnight should fall into the teens, with perhaps a few single-
digit readings where the snowpack is deepest.
Toward daybreak, WAA will increase markedly ahead of a potent low
pressure system tracking along the US/Canadian border. With the
deep snowpack in place upstream of our area, surface temperatures
will lag the warming temperatures aloft leading to the
development of a stout low-level inversion. Any low-level
moisture trapped under the inversion will likely allow for low
clouds and fog to develop, perhaps most likely across central
Illinois where sunshine this afternoon is allowing for sublimation
of the top-most layer of the snowpack. As southwesterly winds
increase after daybreak, any fog that developed across central
Illinois would head our way, leading to what could be a somewhat
gray morning. As is often the case with advection fog aided by
warming temperatures atop a snowpack, confidence is somewhat low
on whether fog will actually develop let along advect into our
area. However, we felt there was enough of a signal in lowering
visibility displayed by high resolution model guidance to justify
at least patchy fog in our gridded database.
High temperatures tomorrow will ride on how much sun we see, with
perhaps the most likely scenario that most areas climb into the mid
30s. Should any sun poke out, especially in areas with little to no
snow (e.g. Rockford), temperatures would easily make a run toward 50
degrees considering 850mb temperatures rising near 8C. In addition,
southwesterly winds would end up much breezier in in our official
forecast. For now, will take the "middle of the road" approach with
both winds and temperatures which is often the course of least
regret this time of year.
Issued at 318 PM CST Mon Feb 7 2022
Tuesday night through Monday...
A large area of positive upper level height anomalies (upper
level ridging) are expected to continue to dominate over the
eastern Pacific into the western coast of North America as a
large upper vortex dominates near the Bering Strait through much
of the week. Between these two features, a strong and active upper
level jet will reside from the northeastern Pacific, eastward
into northern parts of British Columbia and Alberta through the
end of the week. A couple of northern Pacific origin upper level
impulses are then expected to be steered eastward over the
Canadian Rockies before digging southeastward into the Great
Lakes region as clipper systems. The net result of this pattern on
our local sensible weather will be a couple of instances of
precipitation followed by strong and gusty cold frontal passages.
The first digging short wave trough and is expected setup over the
region at the start of the period Tuesday night into Wednesday.
Forecast guidance then continues to advertise several smaller
scale impulses shifting southeastward through the cyclonic upper
level flow, and any one of these may be able to produce some light
precipitation across the region. This looks to especially be the
case on Wednesday into Wednesday evening, especially for areas
generally along and north of I-80. Similar to the previous shift,
we opted to maintain some low end chances for a rain/snow mix
during this period. Overall though, this is not looking to be a
big problem for the area.
Temperatures will turn colder Wednesday night into Thursday as the
heart of the cold arctic airmass quickly clips the area. Expect
highs for Thursday to be held down into the 20s. Warm air
advection should quickly ramp up overhead Thursday evening and
night as breezy southwesterly winds develop in advance of the
next quickly approaching potent clipper system tracking into the
Upper Great Lakes. These breezy winds should result in rising
temperatures Thursday night, with readings likely peaking near 40
during the day Friday.
While the primary track of the surface low with this clipper will
remain well north of the area, we still stand to see a period of
snow, possibly changing to rain Thursday night into Friday as the
exit region of a digging upper jet shifts into the area. This
again should not be a major precipitation event for the area,
as the window for snow should be limited by warming surface
temperatures on Friday.
A strong cold front then shifts across sometime late Friday into
Friday night as the main clipper system shifts over the eastern
Lakes Region. Gusty northwest winds will develop in its wake and
temperatures will turn much colder again for the weekend as a
large area of high pressure builds into the region. Aside from the
threat for some lake effect snow showers over the southeastern
shores of Lake Michigan, the area looks to remain precipitation
free for the weekend at this time.
For the 00Z TAFs...
Issued at 606 PM CST Mon Feb 7 2022
The concerns include:
* Chance for IFR CIGs and reduced VSBY Tuesday morning
* Wind direction Tuesday AM then breezy SSW winds in the afternoon
The upcoming TAF cycle has a conditional risk for low conditions
Tuesday morning, but also a realistic chance of VFR prevailing
through the period. HREF (NAM and WRF members) are indicating
development of radiational fog and low stratus over portions of
western and central Illinois later this evening. A strong low
level inversion is forecast to develop as warmer air moves in aloft.
The conditional scenario for lower conditions (IFR to LIFR CIGs
and IFR to MVFR BR/FG) to reach the terminals would be for what
forms off to the southwest to be advected northeast as southwest
winds increase aloft later tonight into Tuesday morning.
This appears to be a low stratus or nothing scenario
unfolding, as the strong majority of the remaining guidance,
including MOS, supports VFR CIGs with at most a period of MVFR BR
on Tuesday morning. A possible fly in the ointment for the HREF
preferred low conditions is a not well forecast 6-10kft CIG off to
the north and west, which should move overhead this evening.
However, despite low confidence, given conditional lower IFR to
IFR CIG risk and reduced VSBY, opted to highlight the current
favored timing for lower conditions *if they happen* with TEMPO
groups. Winds are also a bit uncertain on Tuesday morning, as they
could be more south-southeast or southeast even at ORD and MDW.
Breezy south-southwest to southwest winds with gusts up to 20 kt
to perhaps 25 kt should develop early Tuesday afternoon. A cold
front approach and passage Tuesday evening will ease and shift the
winds to west-southwest then west.
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Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
805 PM MST Mon Feb 7 2022
Issued at 757 PM MST Mon Feb 7 2022
02z surface analysis had cold front from northeast MT into central
ID. 4mb/3hr pressure rises behind it with steady southeast
movement assisted by shortwave energy diving into MT per water
vapour loop. 00z guidance indicates strengthening of pressure rise
bubble and better downward momentum transfer during peak boundary
mixing tomorrow depicted via Bufkit. Combination of weak cold air
advection and strong mixing should result in a corridor of high
winds from K2WX-KRAP. First batch should occur with cold front,
focused on squeeze area just east of the Black Hills. Second batch
occurs Tuesday during peak mixing. HRRR shows 65kt peak gusts with
front early Tuesday morning, but it can be too aggressive so have
tempered top speeds some.
Forecast updated to account.
.DISCUSSION...(This Evening Through Monday)
Issued at 123 PM MST Mon Feb 7 2022
Upper ridging covers the western CONUS, and the next
shortwave trough to affect our region is pushing into the Pacific
NW. Surface map shows a trough over the northern plains, with a
warm front along its axis across the eastern Dakotas. Winds
across our CWA are westerly 10 to 20 mph. Under mostly sunny
skies, temperatures are warming into the 50s and 60s.
This week`s weather pattern will consist of west coast ridging and
periodic shortwaves moving through northwest flow over our region.
The first wave will approach tonight, and the cold front will begin
crossing our CWA early Tuesday morning. Northwesterly winds will be
strong initially behind the front, and then an early morning lull
is expected before winds increase with daytime mixing; however,
winds aloft are expected to decrease through the day. The HRRR and
NBM 4.0/4.1 show some strong winds just northeast of the Black
Hills around 09-10Z as the front moves over the Black Hills,
enhanced with downsloping. Additionally, several ECMWF ensemble
members show 58+ mph gusts at KRAP early Tuesday morning. RAP/HRRR
forecast soundings have 50+ kt winds just off the surface at 10Z
at KRAP, so a brief period of very strong winds is possible. This
would be supported by strong CAA with the front. However, NAM/GFS
forecast soundings have weaker winds near the surface. After a
morning lull, NBM 4.1 has 50 kt gusts along the typical NW SD to
KRAP corridor Tuesday afternoon, but the NBM 4.0 keeps winds
within advisory criteria. Some 60 mph gusts are supported by
NAM/GFS forecast soundings, but will depend on warmth, mixing, and
the rate winds aloft decrease. Pressure rises are not a
supportive factor of this wind event. Interpreting these mixed
messages, decided to issue Wind Advisories for western SD,
beginning 06Z for NW SD to Pennington Co for the initial
push/downsloping, and beginning 15Z for the rest. Some 60 mph
gusts are not out of the question, but overall expect this event
to be more of a high-end Wind Advisory. Despite the colder air,
highs will be generally in the 40s Tuesday and Wednesday.
On the backside of this system, a weak shortwave beneath the left
exit region of the upper jet will pass over the baroclinic zone,
resulting in some light rain/snow Wednesday into Wednesday night.
While some light snow accumulation is possible on the plains (an
inch or less), a few inches of snow will be possible over the
northern Hills from upslope enhancement. Deterministic solutions
have anywhere from 3 to 9 inches in the northern Hills; the NBM
75th percentile shows 1-3 inches, while the 95th percentile goes
up to 9 inches. With the Froude number expected to stay between
1-2 for nearly 24 hrs, going along with the trend of increasing
snow amounts: generally 3-5 inches in the northern BH, with
around 6 inches possible in the highest elevations.
A brief period of WAA will allow temps to climb back into the 50s
Thursday, before the next shortwave arrives. Friday looks blustery
with snow showers, but minimal accumulations are expected. Cold
airmass then shifts eastward for the weekend, resulting in mild and
.AVIATION...(For the 00Z TAFS Through 00Z Tuesday Evening)
Issued At 434 PM MST Mon Feb 7 2022
VFR conditions are expected through the TAF forecast period. A
cold front will move through the Northern Plains late this evening
into early Tuesday morning, switching winds from westerly to more
northwesterly, and increasing speeds to 20-30 knots with gusts to
Issued At 123 PM MST Mon Feb 7 2022
Strong winds on Tuesday and dry fuels will create conditions
conducive to fire spread. The GFDI will be very high to extreme on
the western SD plains. However, since the minimum RH is expected
to be 25% or higher, opted to refrain from issuing a Fire Weather
SD...Wind Advisory from 8 AM MST /9 AM CST/ to 5 PM MST /6 PM CST/
Tuesday for SDZ014-027-030-032-041>044-046-047-049-074.
High Wind Warning from 11 PM this evening to 5 PM MST Tuesday
Wind Advisory from 11 PM this evening to 5 PM MST Tuesday for