Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/25/23
Area Forecast Discussion
National Weather Service Amarillo TX
528 PM CST Tue Jan 24 2023
...New AVIATION...
.SHORT TERM ...
(This evening through Wednesday night)
Issued at 137 PM CST Tue Jan 24 2023
As of the latest 18Z observations across the Panhandles, on the
backside of an elongated H500 low pressure system based off the
RAP analysis, there is a another band of snow that has developed.
This should move east across the southern Texas Panhandle through
this evening. Leftover snow showers may linger tonight across the
eastern Texas Panhandle, with precipitation coming to an end for
all of the Panhandles by overnight tonight. Additional snowfall
accumualtions this afternoon and evening will range from a
dusting to an inch or two in the most persistent areas of
snowfall.
Going into tomorrow morning, as temperatures start below
freezing, any untreated roadways and/or packed snow from vehicles
along with overpasses with our higher water content snowfall
event, this could result in some black ice to develop and cause
some slick spots for the Wednesday morning commute. Overall, dry
conditions return to the Panhandles as NW surface flow on the
backside of the departing low pressure system. With a decent NW-
SE H850-700 30-45 kt jet parallel to the southern Rockies, slight
perturbations in the mean flow may help to develop localized lift
for flurries/sprinkles tomorrow afternoon for the western
Panhandles. No snowfall accumulations are expected. High
temperatures tomorrow will range from the mid 30s to mid 40s. Low
temperatures tomorrow night will range from the mid teens to lower
20s.
Meccariello
&&
.LONG TERM ...
(Thursday through next Monday)
Issued at 137 PM CST Tue Jan 24 2023
Dry conditions are expected throughout the long term forecast
period. H500 northwesterly flow eventually becomes westerly by the
weekend with persistent convergence aloft in the synoptic pattern.
Temperatures through Saturday will slowly climb to near average
for late January. Latest 24/12Z model and numerical guidance shows
the potential of a stronger cold front making its way into the
Panhandles with H850 temps as low as -8 to -10C. More favored for
below average temperatures to round out the last few days on
January on this coming Sunday and Monday.
Meccariello
&&
.AVIATION...
(00Z TAFS)
Issued at 525 PM CST Tue Jan 24 2023
MVFR and IFR cigs are observed at all TAF sites to start the 00Z
TAF period. Some -SN also being reported at KAMA to start the TAF
period. Snow should come to an end by 02-03Z for all TAF sites.
Cigs should also improve to VFR levels for all TAF sites by 06-12Z
Wednesday. Cigs will then stay at VFR levels throughout the
remainder of the TAF period. Winds will be out of the northwest at
10-20 kts with higher gusts at times.
Meccariello
&&
.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX 20 39 17 40 / 20 0 0 0
Beaver OK 22 40 18 44 / 30 0 0 0
Boise City OK 19 37 15 42 / 0 10 0 0
Borger TX 22 43 19 46 / 20 0 0 0
Boys Ranch TX 19 42 15 44 / 10 10 0 0
Canyon TX 20 39 16 39 / 10 0 0 0
Clarendon TX 24 40 20 42 / 20 0 0 0
Dalhart TX 18 40 14 43 / 0 10 0 0
Guymon OK 20 40 17 44 / 0 0 0 0
Hereford TX 19 40 16 40 / 0 10 0 0
Lipscomb TX 22 41 19 44 / 30 0 0 0
Pampa TX 22 40 19 42 / 40 0 0 0
Shamrock TX 24 43 23 45 / 30 0 0 0
Wellington TX 26 45 23 46 / 20 0 0 0
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...Winter Weather Advisory until midnight CST tonight for TXZ009-
010-013>015-018>020.
OK...None.
&&
$$
SHORT TERM...29
LONG TERM....29
AVIATION...29
Area Forecast Discussion
National Weather Service Binghamton NY
942 PM EST Tue Jan 24 2023
.SYNOPSIS...
A few lake effect snow showers or flurries will continue
into tonight over Central NY. The next winter storm then moves
through the area Wednesday into Wednesday night, with snow
changing to a wintry mix and even rain. Colder air moves back in
by the end of the work week with lake effect snow showers
possible Thursday into Friday.
&&
.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
Mesoscale modeling is still bringing an initial band of snow
across the NY/PA border counties in the morning hours
Wednesday. The NAM has come down from it`s extremely bullish 18Z
run to match closer to the current RAP and HRRR 00z runs. This
first band of snow could produce a couple inches of snow before
the main round of snow moves in around noontime. This overall
shifted the QPF axis further northwest tomorrow morning,
increasing totals in the Ithaca and Elmira areas while lowering
totals in the Wyoming valley into Pike county PA.
Most places are still looking at a burst of snow in the early
afternoon before a change to brief mixing and rain. Several
inches of snowfall is expected within a few hours at any given
location. Top amounts of 4-6 inches along the NY/PA border that
get hit by both batches, along with elevation enhancement in
Sullivan and northern Oneida counties in NY.
Early evening update...
A look at model soundings and some observations are indicating
the potential for some patchy freezing drizzle through the
evening hours. This and lingering moisture freezing on road
surfaces may lead to some slick spots. Issued an SPS into the
overnight for this potential. Moisture is lacking for anything
in NE PA with data suggesting just snow along the NY Thruway.
Both the NAM and RAP have a narrow band of intense snow forming
by mid to late morning along the NY/PA line that stays nearly
stationary or slowly drifts north into the early afternoon. A
quick 2-4 inches could fall in this window. However, confidence
is not high enough to adjust snowfall totals at this time. It
should be noted other modeling does not have this band at all or
has it in a different location.
355 PM Update...
An impactful winter storm will move across the area Wednesday
into Wednesday night, with some lingering lake effect snow into
Thursday for areas of Central NY. Winter weather Advisories are
in effect for the entire forecast area, except Winter Storm
Warnings for Sullivan County and northern Oneida County.
For this evening and tonight there will be some generally light
lake effect snow showers across Central NY and also perhaps some
pockets of drizzle or freezing drizzle. As temperatures fall
below freezing we will have to watch closely for any of this
freezing drizzle to develop. The highest PoPs and snow amounts
from this lake effect will be across and north of the Thruway
corridor where up to 1 inch of snow could fall tonight.
Otherwise, the rest of the forecast area should dry out under
mostly cloudy skies tonight. Overnight lows dip down into the
20s areawide. The northwest winds become will diminish after
sunset, becoming light and variable after midnight...then
turning east-southeast in the predawn hours.
Wednesday and Wednesday night will be a very active period, as a
quick hitting winter storm moves into the area. Confidence has
increased in at least advisory level amounts across most of the
forecast area with the latest guidance, with increased
probabilities for warning level amounts in Sullivan and
northern Oneida County.
Strong isentropic lift arrives quickly early Wednesday morning,
this along with being in a favored coupled jet structure (right
entrance region of a 150 kt jet over northern New England) will
produce strong atmospheric lift over the region. 12z GFS is
showing very strong warm air advection, by midday Wednesday,
along with a 50-60 kt southerly jet at 850mb. This will overrun
the cold pool of air in place to again, produce impressive lift.
On top of all of this, both the NAM and GFS are showing a strong
area of 850-700mb frontogenesis pushing through from south to
north between 15z to 21z or so Wednesday.
The latest CAMs are all on board with a band of snow, developing
quickly early to mid morning Monday over NE PA and quickly
spreading north. There is a chance for a dry slot to develop
south of this initial band of snow, which could drift north to
along RTE 6 in NE PA by mid-morning. As the initial band lifts
north into the southern tier of NY, lift increases and the snow
should become heavy. Another area of snow quickly fills back in
over any small dry slot by late morning over NE PA. This is when
the heaviest snow looks to occur over the Twin Tiers of NY/PA.
The snow will spread across the rest of CNY by mid to late
morning, also becoming heavy at times. The HREF is showing
numerous members with 0.05 to 0.15" of QPF per hour under this
area of snow...and with snow to liquid ratios of 12-15:1 this
could easily translate to snow rates of 1-2 inches per hour. The
best Omega is just below the snow growth zone in the NAM
forecast soundings, but accumulations should still be quite
efficient on Wednesday. This is a major concern for increased
impacts Wednesday morning into the afternoon hours, even across
the winter weather advisory areas (and warning areas). The snow
begins to mix with sleet and rain over the lower elevations of
the Finger Lakes and Wyoming Valley by the mid to late afternoon
hours, then across the Binghamton area by early evening, and
the rest of CNY by 6 to 9 PM. This period of mixing looks to be
rather brief for most areas with light accumulations of sleet
and patchy freezing rain possible (mainly higher elevations). By
evening, most of the area is expected to change over to light
rain or drizzle, except the highest elevations of the Catskills
and norther Oneida where light freezing rain could linger. Storm
total snow is expected to range from 2 to 5 inches for most of
Central NY, except 3 to 6 inches for the Southern Tier and 5 to
10 inches in northern Oneida. For NE PA, snow amounts will also
range from 3 to 6 inches, with localized amounts up to 7 inches
over the higher elevations of the northern tier. Will have to
watch the latest CAMs and high res guidance closely, as the 18z
NAM has trended a bit further north and heavier with snow amounts
across the far northern tier of PA and the Southern Tier of NY.
Another aspect of this storm system will be increasing southeasterly
winds, between 15-25 mph with gusts of 30-40 mph by Wednesday
afternoon and evening. This will allow for areas of blowing and
drifting snow to develop over the open areas in the higher
terrain...however this potential will decrease by late Wednesday
evening as temperatures rise above freezing.
Heading into Thursday night, much of the area will be under a
mid level dry slot. This will mean just some scattered rain
showers and drizzle over the area as surface temperatures rise
into the mid and upper 30s...even some low 40s in the Wyoming
Valley. During the predawn hours a cold front sweeps in from the
northwest, bringing much colder air aloft and eventually slowly
cooling surface temperatures. Lingering rain showers will
transition back to snow showers toward daybreak Friday.
Additional accumulations will be possible, mainly across
northern Oneida County, where another 1-2 inches may fall.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
310 PM Update:
As the low pressure system departs to the northeast, a gusty
westerly flow will be developing, which will allow for lake
enhanced snow showers Thursday through Friday morning. This will
especially be the case for areas along and north of the NY
Thruway corridor. This will bring an additional few inches of
snow to those areas. The lake enhanced snow will transition to
more of a pure lake effect setup Thursday night into Friday
morning with 850mb temperatures falling to around -13C and a
west-northwesterly flow.
By Friday, high pressure will be moving into the area, which
will bring an end to any lake effect snow showers. This will
also bring the best chance for seeing some limited sunshine,
particularly across Northeast PA. That being said, most of the
area is expected to remain mostly cloudy. Temperatures will be
near-normal with highs expected to be in the upper 20s to mid
30s.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
310 PM Update:
Active weather will continue in the long term period, beginning
with a shortwave moving through on Saturday. Then another
system may impact the region Sunday into Monday, which may bring
snow or a wintry mix to the region, depending on the track and
strength of the system. Aside from some lake effect snow
showers, a brief break is expected late Monday through Tuesday,
before another system may impact the region mid-week.
Temperatures will be on the colder side, but not really outside
of the norm for this time of the year (highs in the 20s and 30s;
lows in the teens and 20s).
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
VFR conditons expected overnight across the region. RME may have
a few off and on periods of MVFR visby due to passing lake
effect snow showers but prevailing conditions will be VFR.
A storm moves into the area Wednesday morning, spreading snow
from SW to NE. Light snow brings MVFR cigs and vis to
ELM/AVP/BGM/ITH between 13-15z. Heavier snow is expected mid-
morning through early afternoon, which will drop conditions down
to LIFR(ELM IFR). A changeover to mixed precipitation with
freezing rain, sleet and snow is expected mid afternoon, but
conditions will remain IFR through the TAF period.
SSE wind gusts between 20-30kts are expected mid-morning
through the end of the TAF period. Blowing snow from these
gusts could enhance visibility restrictions.
SYR and RME are expected to experience the same conditions,
just a couple hours later than the southerly terminals. SYR
should see a IFR visby as the snow moves in around 17z, while
RME should go IFR around 19z. Winds pick up between 20-21z with
ESE gusts 35-30kts. A changeover to freezing rain, sleet and
snow is expected around 00z and will be addressed in the next
TAF cycle.
LLWS out of the SE from 40-45kts is expected to spread across
the southern terminals Wednesday afternoon through the end of
the TAF period.
Outlook...
Wednesday night Thursday... LLWS expected Wed night. Rain
showers Wed night bring MVFR restrictions. Snow showers Thursday
bring restrictions to NY terminals.
Friday Through Sunday...Some MVFR ceiling restrictions with a
chance of snow showers.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...Winter Weather Advisory from 7 AM to 10 PM EST Wednesday for
PAZ038>040-043-044-047-048-072.
NY...Winter Storm Warning from 10 AM Wednesday to 7 PM EST Thursday
for NYZ009.
Winter Weather Advisory from 7 AM to 10 PM EST Wednesday for
NYZ015>018-022>025-044-055>057.
Winter Weather Advisory from 9 AM to 10 PM EST Wednesday for
NYZ036-037-045-046.
Winter Storm Warning from 7 AM to 10 PM EST Wednesday for
NYZ062.
&&
$$
SYNOPSIS...MJM
NEAR TERM...MJM/MWG
SHORT TERM...BJG
LONG TERM...BJG
AVIATION...JTC
Area Forecast Discussion
National Weather Service Columbia SC
713 PM EST Tue Jan 24 2023
.SYNOPSIS...
Dry weather will continue through this evening, with increasing
moisture and rainfall chances towards Wednesday morning. A cold
front will cross the area Wednesday afternoon, bringing showers
and possibly a few thunderstorms. Cool and dry weather expected
until late in the weekend behind the front.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
The night starts off clear and dry, but southerly winds, and an
increasing low-level jet, will bring low-level moisture back
towards the area through the overnight hours ahead of an
approaching cold front. This will bring an increase in cloud
cover after Midnight, and then increasing rain chances across
the western cwa late tonight and into the morning hours.
Overnight lows are milder due to the cloud cover and expected
southerly winds, with readings in the upper 30s north to the
middle 40s south.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
Impactful Weather Wed., With Gusty Winds & a Conditional Threat
for Severe Weather Expected...
Our next system is currently taking shape over the south-central
Plains States. A closed 500 hPa low is expected to take on an
increasingly negative tilt over the next 24 hours as it
propagates into the OH Valley out of the desert southwest.
Ahead of this, a strong surface high pressure and very dry
airmass (characterized by PWs <0.25") is expected to retreat
quickly off the coast of the Mid- Atlantic as intense upper
level diffluence forces a strong surface low across the lower OH
Valley region. By 7am Wednesday, these features are forecast to
be across western TN, quickly pushing northeastward. A warm
front will be present near our region, quickly pushing northward
in advance of intense warm air advection. Guidance shows
showers developing ahead of this within increasingly strong
isentropic ascent at the 295-300k surface. These should quickly
push northward with the warm front. As this pushes northward,
low- level flow is expect to quickly increase in strength.
Surface wind vectors will likely remain out of the south or
southeast due to strong surface pressure falls, with 850 hPa
flow out of the southwest. This will create fairly strong
directional shear, with speed shear already a given with 50-60
knots at 850 hPa. This kind of low-level wind will create strong
surface winds as soon as the warm front begins moving northward
and our ability to mix increases. As a result, we`ve posted a
Lake Wind Advisory starting at 10a tomorrow for all areas. Winds
tomorrow will likely gust 35-40 mph, with occasional gusts
upwards of 45 mph.
This will precede & follow the line of showers/storms, expected
to push into the region beginning around 10a and exiting around
4p. Given the magnitude of the wind shear and forcing for
ascent, this line of storms bears close watching. 3km shear
vectors will be in the 40-50kt range out of the southwest or
south-southwest, favoring a threat of spin up tornadoes in
addition to wind damage. However, the magnitude of the threat is
conditional right now. This is due to the lack of instability
within guidance right now. I don`t really see a path towards
significant instability, but with linear convection, one of the
more important things to look at is 0-3km MLCAPE. Guidance is a
bit split there, with the latest RAP showing values of 40-60j/kg
developing across our eastern counties ahead of the line early
tomorrow afternoon. The HRRR is not as bullish, showing a
decrease in run to run values between the 06z & 12z runs. So the
severe aspect of this is quite uncertain at this time. If we
get breaks in the clouds ahead of the line of storms (most
likely in the eastern 1/3 of the CWA), then we could realize
more 0-3km CAPE than we are seeing right now. I think that is a
reasonable potential outcome, and the SPC has placed the areas
along and southeast of a line from Augusta- Columbia-
Chesterfield in a Slight Risk for severe storms. Again, the
greatest threats are damaging winds and isolated, spin-up
tornadoes. The timeframe for this is from 10a to 4p.
The gusty winds will likely continue behind the convection, with
temperatures staying up into the evening hours. Even still, the
gusts should begin to subside after 7p, with some gusts up to 30
mph tomorrow night. Given this, the Lake Wind Advisory will
expire at 2a on Thursday. Highs tomorrow should be in the mid
and upper 60s, with some low 70s possible in our eastern
counties. Expect rain to continue behind the line of storms,
owing to the front becoming a bit of an anafront tomorrow
evening. The rain will develop within some isentropic ascent
between the 310-315k surfaces, so it should be light to moderate
as opposed to the moderate-heavy rain we see with the line of
showers/storms. Expect all of this to be out of here after 2a on
Thursday, with cold air advection continuing to bring cooler
and drier air into the region for Thursday.
Temps will start the day in the upper 30s and low 40s for many
on Thursday, likely not getting out of the mid 50s for highs.
Stuck on the cooler end of guidance, owing to strictly westerly
flow that will make CAA more efficient as opposed to downslope,
northwesterly flow. Expecting few clouds due to low PW below
half an inch. Thursday night, temps should get cold but kept our
lows a bit warmer than guidance. We shouldn`t radiate
efficiently due to the surface high still being well to our
southwest and a pressure gradient keeping winds up a bit. Still,
look for low and mid 30s across the region by Friday morning.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
Quiet weather is expected to begin this period, as strong
surface high pressure builds into the FA behind Wednesday`s
cold front. The center of the surface high looks to push into
the region from the west and approach by Friday night, with near
to below normal temps expected. Highs likely won`t get out of
the 40s on Friday, and trended lows on Friday night towards min
dewpoints, which bottom out in the upper 20s. We should see the
best radiational cooling that night, so expect cool temps. PWs
look to be in the 30-50% of normal range from Friday through
early Sunday, so dry weather will continue in this period, and
temps will slowly moderate on Saturday. Our next system arrives
on Sunday night & Monday, with rain and cool temps likely. It
looks like that low track could be to our south again, with most
ensembles keeping our rainfall below an inch. Guidance shows
another system quick on its heels by the middle of next week,
with rain and roller coaster temps likely again. Didn`t deviate
too much from the NBM in the long range, as EFI isn`t
highlighting many areas of opportunity. Did lean towards the
cooler end of guidance for Friday night with ideal radiational
cooling, but otherwise went with the NBM.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
VFR Conditions giving way to restrictions and LLWS around
daybreak Wednesday.
Clear skies across the area will give way to mid and high level
clouds through midnight. Moisture will rapidly increase during
the early morning with low level clouds developing during the
early morning hours and giving way to MVFR conditions around
daybreak. A few showers are possible during the morning however
with low confidence have continued with VCSH. The cold front
will move into the area around midday with showers and IFR
restrictions through the afternoon and into the evening. Very
late in the period winds will veer to southwesterly at all sites
except OGB with stronger winds and wind gusts expected for
several hours just behind the front.
Of substantial note are the low level winds with a low level jet
approaching 60 knots with passage of the system. Have kept LLWS
from 09z through the end of the period and increased shear
speeds to 40 knots or higher from 17z through the end of the
period.
EXTENDED AVIATION OUTLOOK...Lingering rain and associated
restriction Wednesday evening. Breezy and gusty winds with LLWS
expected through much of Wednesday night. Breezy conditions
Thursday. Restrictions possible late Sunday as the next low
pressure system moves into the region.
&&
.HYDROLOGY...
Rises and minor flooding on the Edisto River at Orangeburg will
continue, with minor flooding also possible along portions of
the Congaree through mid-week. Additional rainfall is expected
with another storm system Wednesday which could push levels to
near flood stage or beyond once again by the end of the week at
a few locations. Interests along area rivers are encouraged to
monitor the situation.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...Lake Wind Advisory from 10 AM Wednesday to 2 AM EST Thursday
for GAZ040-063>065-077.
SC...Lake Wind Advisory from 10 AM Wednesday to 2 AM EST Thursday
for SCZ016-018-020>022-025>031-035-037-038-041-115-116-
135>137.
&&
$$
Area Forecast Discussion
National Weather Service Cheyenne WY
500 PM MST Tue Jan 24 2023
.SHORT TERM...(This evening through Thursday night)
Issued at 300 PM MST Tue Jan 24 2023
The main focus of the short term forecast is the potential for high
winds and blowing snow in the wind prone areas Thursday through
early Friday. In addition, several weak clipper systems will deliver
a few rounds of light snow over the next few days.
Currently, satellite shows largely clear skies over the region, a
rare treat in recent days. Some low clouds linger over the mountains
and portions of Carbon county, and a few cirrus clouds associated
with the last system are clearing out of the I-80 corridor. However,
this sunny break will likely be short-lived. Increased cloud cover
associated with the incoming barrage of weak clipper systems is
already creeping into northern Wyoming and South Dakota. On the
large scale, we have a broad trough located over much of the central
US with a blocking ridge fixed just offshore of the West Coast.
North to northwest flow remains dominant aloft over our region. Over
the next several days, numerous weak shortwaves and vort-maxes will
pass near and over the area, leading to continued cold temperatures,
cloudy skies, and eventually increasing winds.
For tonight, clear skies early on top of a persistent snowpack
should allow temperatures to drop quickly after sunset, particularly
in the usual cold spots such as the Laramie Valley and Alliance
area. However, increasing cloud cover and winds after midnight will
likely slow the plummeting temperatures and perhaps warm things up
slightly. A few snow showers will also redevelop late this evening
over the area and continue through Wednesday as very modest lift
associated with the vorticity advection aloft pushes through. North
to northwest flow will favor the Pine ridge and north side of the
Cheyenne ridge for accumulation over the high plains, in addition to
the mountains. During the day on Wednesday, forecast soundings show
fairly steep lapse rates setting up over the area. Thus, wouldn`t be
surprised to see snow showers take up more convective
characteristics during the afternoon and early evening hours. By
Wednesday evening, we could see 1-3 inches in these areas, including
around Lusk, with a dusting to an inch elsewhere. Accumulations
around 2 to 6 inches are also possible in the mountains (Snowy,
Sierra Madre, and North Laramie ranges) and a dusting to 3 inches
near the I-80 summit. Depending on how things trend overnight, a few
advisories could be needed, but for now opted to issue a Special
Weather Statement for light snow in Converse and Niobrara counties.
Snow shower activity should wind down late Wednesday night with a
brief lull in the clipper parade Thursday morning. Otherwise,
Wednesday looks cold and windy for much of the area. Stronger flow
aloft is returning to the high plains, and thus expecting winds of
20 to 30 MPH with gusts to 45 MPH across much of the region along
and east of I-25. Maximum wind chills may only reach the single
digits to teens.
For Thursday, a slightly stronger shortwave will dive down and
initiate surface cyclogenesis over the Canadian Prairie. This
surface low will move into Manitoba by afternoon, and trail a fairly
strong surface trough down to the southwest towards our area. With
strong surface high pressure firmly entrenched over the interior
Rockies, the cross barrier pressure gradient will become fairly
strong. Thus, expecting our reprieve from the high winds to come to
a close by Thursday morning. Highest confidence in strong winds is
in the Arlington/Elk Mountain area, but winds also look fairly
likely across the Laramie range. The surface low will be well off to
the east which should allow strong winds to spill over much of the
high plains. However, confidence in this reaching High Wind criteria
is only high enough in the wind prone areas at this time. Winds
aloft are not very impressive, which reduced confidence for other
areas. We could see some mountain wave activity though, particularly
Thursday evening, which may lead to high winds reaching eastern
Platte and central Laramie counties, but confidence in this remains
fairly low. Opted to issue a High Wind Watch beginning 8AM Thursday
and continuing through 8PM Friday for Arlington/Elk Mountain. Models
show the MSLP gradients waning significantly by late Thursday night,
switching the event to being driven more by winds aloft on Friday.
Since models show the surface trough sandwiched right against the
Laramie range during the day Friday, opted to issue a watch only for
the first part of the event for the wind prone areas of the Laramie
range. Winds are likely to continue through Friday, but details on
this can be found in the long term section below.
.LONG TERM...(Friday through Tuesday)
Issued at 300 PM MST Tue Jan 24 2023
Forecast challenges deal with strong winds Friday...followed by
snow chances on a daily basis through the middle of next week.
Strong winds ongoing Friday morning with Craig to Casper 850/700mb
gradients at or above 60mtrs through the day. GFS 700/750mb
windspeeds above 60kts along and west of the Laramie Range. WOuld
be a good bet that the wind prone areas will be hitting warning
level winds late Friday morning through the afternoon and early
evening.
Arctic front drops into the area from the northeast Friday evening
into Saturday and settles along the east slopes of the Laramie
Range. Northeast flow behind the front with very cold temperatures
behind the front. 700mb temperatures -12 to -14C and 850mb
temperatures -10 to -12C across the northern Panhandle into
Converse/Niobrara Counties Saturday morning. Looks like the front
does clear the Laramie Range Saturday afternoon with easterly
winds becoming widespread over the CWA. Light QPF forecast on both
the GFS and ECMWF. Looks like all counties will be experiencing
this high PoP/Low QPF event Saturday afternoon
Arctic front remains anchored across our western zones with
clipper systems moving through that will create near continuous
light snow and very cold temperatures Over the next several days.
Clipper system Sunday could produce some pretty good snowfall.
Will need to watch that. GFS showing 6-12 hour QPF of .3 to .4
across Carbon County into Monday. With high snow ratios...may need
some winter headlines for much of Carbon County Sunday and
Monday.
Very cold next week with 700mb temperatures ranging from -16C
across our western zones to -24C across the northern Nebraska
Panhandle. With almost continuous northeast upslope flow...clouds
are going to stick with us through at least the first half of next
week. Very cold temperatures with highs in the teens and upper
single digits. Overnight lows could very well fall below
zero...especially east of the Laramie Range in the colder airmass.
&&
.AVIATION...(For the 00Z TAFS through Wednesday evening)
Issued at 500 PM MST Tue Jan 24 2023
Brief clear skies this evening until the next Alberta Clipper moves
south along the Front Range tonight and Wednesday. Expect cloudy
skies with CIGS lowering between 1500 to 3500 feet AGL for most
terminals after 06z tonight through most of Wednesday. Scattered
snow flurries or occasional snow showers are expected for all
terminals along with a wind shift into the north.
HAZARDS/WEATHER TRENDS: MVFR to near IFR conditions are expected as
early as 06z to 12z Wednesday for KRWL and KLAR, but later (12z to
18z) for KCYS and the western Nebraska terminals. Periods of IFR
conditions are expected, but models do not agree on the timing, so
may need to handle this with TEMPO groups. HRRR shows snow flurries
or snow shower activity starting at KRWL and KLAR around 06z, and
then closer to 12z for the other terminals. Kept VCSH and BR since
most of this activity will be light and/or pretty brief. IFR VIS is
certainly possible Wednesday, but predictability on timing and
coverage are low at this time.
&&
.FIRE WEATHER...
Issued at 300 PM MST Tue Jan 24 2023
Minimal fire weather concerns over the next week with cold
temperatures and existing snowpack in place. Winds begin to pick
up Wednesday evening through Friday. High Wind Watches in effect
for the wind prone areas of southeast Wyoming from early Thursday
morning through Friday before easing. Cold front moves into the
area from the northeast...bringing much colder temperatures and
light snow to the area Friday. This front stays in the area
through much of next week with daily chances for snow and very
cold temperatures.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Watch from Thursday morning through late Thursday
night for WYZ106-116-117.
High Wind Watch from Thursday morning through Friday evening for
WYZ110.
NE...None.
&&
$$
SHORT TERM...MN
LONG TERM...GCC
AVIATION...TJT
FIRE WEATHER...GCC
Area Forecast Discussion
National Weather Service Lincoln IL
912 PM CST Tue Jan 24 2023
.SYNOPSIS...
Issued at 228 PM CST Tue Jan 24 2023
Snow is expected across central Illinois late this evening and
overnight. Snow could be heavy at times across portions of east
central and southeast Illinois. The heaviest snow will taper off
midday Wednesday, but additional light snow accumulations will
linger into Thursday. Expect highs in the lower to mid 30s
Wednesday and upper 20s to around 30 degrees Thursday.
&&
.UPDATE...
Issued at 912 PM CST Tue Jan 24 2023
Low pressure with the approaching storm system is currently
centered near southeast Arkansas, moving northeastward. The
precipitation ahead of the low has spread to just south of St
Louis, with a narrow band of light rain ahead of that. Dry layers
observed in the ILX sounding will likely keep precipitation from
reaching the ground initially, although wet-bulb effects will
help to bring temperatures down rapidly once precipitation begins.
Current trends are slower with precipitation onset than afternoon
forecast, and have made updates to slow arrival of precipitation.
Otherwise, forecast appears on track, with heaviest precipitation
after midnight into Wednesday morning, temperatures trending down
from current mid-upper 30s down to lower 30s by morning, and
accumulations highest east of I-55 through the I-70 corridor,
generally 4 to 7 inches in that area.
&&
.SHORT TERM...(This evening through Thursday)
ISSUED AT 228 PM CST Tue Jan 24 2023
A Winter Storm will impact portions of the region, particulary
areas near and south of a Taylorville to Champaign line tonight
into Wednesday afternoon.
This afternoon, water vapor imagery reveals a strong upper low
over western Texas while surface obs indicate low pressure is
located over southern Texas. The surface low is progged to deepen
as it lifts across the lower/mid Mississippi Valley overnight to
the upper Ohio River Valley midday Wednesday. Ahead of the low,
strong warm air advection will overspread portions of southern
into central Illinois overnight. This will result in the initial
wave of precip moving into the region with enhanced snow rates
within a narrow corridor of strong frontogenetic forcing oriented
along the I-70 corridor overnight. Precip should begin to taper
off mid to late morning with passage of the H5 wave and the
stronger forcing (WAA/Fgen) shifting off to our east.
In terms of snow amounts, the area under the Winter Storm Warning
is still on track to see 4 to 7 inches from roughly Taylorville
to Champaign southeast through the I-70 corridor with a sharp
cutoff in amounts on either side of the axis of heaviest snow.
With perhaps a county width or less separating the highest snow
totals, the rest of central Illinois should experience 2 to 3
inches of snow, locally 4 inches.
Precip type concerns: Temperatures are in the lower to mid 40s
across portions of central Illinois south of I-72 this afternoon
and will gradually fall into the lower to mid 30s overnight. At
the onset of precip, there may be enough lingering warmth within
the boundary layer to support rain or a rain/snow mix, but precip
should generally transition to and stay as snow. The exception
will be the far southern counties in the forecast area south of
I-70, and in particular, Lawrence County. As strong mid level warm
air advection overspreads the region overnight, a modest warm
nose develops and pokes into the far southeastern portions of the
forecast area. 800-700mb layer max wetbulb temps bring the zero
degree isopleth right up to Lawrence County and if this occurs,
partial melting aloft may support at least a little bit of sleet.
There is low confidence in this occurring but bears watching.
Mesoscale Banding Potential: Guidance continues to indicate a
strong signal for mesoscale banding to develop. Between roughly
06Z to 12Z, RAP indicates a layer of strong fgen occurring between
550mb and 800 mb and oriented along and near the I-70 corridor.
The cold side of this feature will be the favored location for a
band of heavier snow to develop. Lapse rates above the strongest
fgen are steep, with a few hours of forecast soundings indicating
even some upright instability developing that will allow a deep
vertical response to forcing. 1.0 to 1.5 inch per hour snow rates
are possible within the snow band and its location will determine
the highest snowfall amounts, with some potential to see localized
amounts to around 8-9 inches (HREF 90th percentile / NBM 95th
percentile)
The main H5 wave will depart to our east by around midday
Wednesday marking the end of the heaviest snow accumulations.
But, lingering low level cyclonic flow with steepening low level
lapse rates along with a clipper digging southeast across the
Upper Midwest will prolong light snow and flurry chances the rest
of the day Wednesday and into the day Thursday as well. Additional
minor accumulations of an inch or two will be possible, with the
highest amounts focused near the I-74 corridor.
.LONG TERM...(Thursday night through Tuesday)
ISSUED AT 228 PM CST Tue Jan 24 2023
The upper trough that was responsible for the midweek storm will
eventually push east of the area later this week. A couple weather
systems will impact the region on Friday with another later
Saturday into Sunday, though precipitation amounts look minor at
this time. Temperatures will be near seasonable most days through
the weekend as flow aloft transitions to more zonal, which would
suggest possibly a mix of rain and snow for the Friday system.
However, as mid-level heights rise/temperatures aloft increase
this weekend as flow becomes more zonal, forecast soundings
suggest a wintry mix of rain, snow, and possibly freezing rain for
some later Saturday into Sunday.
Uncertainty remains going into the new week, though the latest
indications suggest a strong surface high will build into the
Plains and migrate east as a trough moving onshore the Northwest
US pushes the high east. Ensemble guidance continues to hedge at
possibly a cool down by early next week, though the range of
potential temperatures is still pretty large. The CPC continues to
highlight below normal temperatures from the latter half of the
weekend into the middle of next week. If this pans out and we are
able to hold onto most of our snowpack from the midweek storm,
temperatures may start trending toward the lower end of guidance.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 600 PM CST Tue Jan 24 2023
Widespread IFR conditions will develop 05Z-07Z across the central
IL terminals as snow spreads northward with an approaching winter
storm system. Initially cigs will fall fastest, but IFR vsbys will
also develop within a few hours. LIFR conditions will be possible
at times as well, mainly 09Z-15Z, especially for KDEC and KCMI
which will be in the path of the heaviest snow, while somewhat
lighter snow is expected to the west. Until then, MVFR cigs look
to linger at KPIA and KBMI with a short break possible. Conditions
look to begin some improvement after 16Z-18Z with lighter snow,
although IFR conditions will likely continue through the period.
Winds E up to 5 kts this evening, gradually shifting to NE, and NW
overnight into Thursday morning. Wind speeds will increase to
10-15 kts by 15Z-18Z.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 6 PM CST Wednesday for ILZ027>031-
036>038-040>043-047>051.
Winter Storm Warning until 6 PM CST Wednesday for ILZ044>046-
052>057-061>063-066>068-071>073.
&&
$$
UPDATE...37
SYNOPSIS...Deubelbeiss
SHORT TERM...Deubelbeiss
LONG TERM...NMA
AVIATION...37
Area Forecast Discussion
National Weather Service Indianapolis IN
1049 PM EST Tue Jan 24 2023
.Mesoscale Update...
Issued at 1049 PM EST Tue Jan 24 2023
The forecasted winter storm is on our doorstep as precipitation is
expected to begin from southwest to northeast within the next few
hours. This mesoscale update is going to focus on the
development/progression of the system currently in Arkansas,
Louisiana, and Tennessee and how models are handling the scenario
compared to observations.
As of 02z, the lowest pressure of 1004.3 mb was found in surface obs
was located just NE of Alexandria, LA. As of the writing of this
discussion, the surface low is still broad, but should tighten and
deepen over the next few hours. The broad surface low as of 10PM is
likely located in NE Louisiana near Winnsboro with a min pressure of
1004/1005mb. Comparing observations with 00z runs of short term hi-
res models shows that the low is right on track, possibly a county
or two further west. However, models struggle with developing lows
so this is not unexpected so early in the cyclogenesis stages. The
center of the low may also wobble around over the next few hours as
it gets more organized. Will have to watch the low later tonight as
it develops and follow its track as it compares to models. A storm
track deviation as small as 20 miles south or north could move the
axis of heavier snow in either direction resulting in significant
changes in the forecast for a few counties along the I-70 corridor
on the edge of the heaviest snowfall.
Looking at the radar, the dry slot associated with the expansive
precipitation shield northwest of the low has reached into northern
Arkansas. Both the NAM3K and the RAP have shown the dry slot getting
just up to Fort Smith, then the deformation band moves in and pivots
over that area. Radar observations show this happening very nicely,
increasing confidence that the models are initializing well and have
a good handle on precipitation. Further back towards Dallas, which
is getting the back edge of the deformation band, reports show
mostly snow with some pockets of rain mixed in. This matches well
with short term models, however looks like models may not be cold
enough on the backside of the low as observations show more snow in
areas where models suggest rain. Confidence is rising that P-type
tomorrow morning and early afternoon will be mainly snow on the
backside of the system, even for portions of Southern and South
Central Indiana. Strong forcing and high precipitation rates could
keep the column cooler resulting in mainly snow, rather than a mix.
However, still will have to watch surface temperatures as heavier
snow falling at 33-34 degrees will have to overcome melting
occurring in order to accumulate.
Ahead of the low in Tennessee this evening, ground observations show
surface temperatures in the upper 30s to near 40, but with mixed
precipitation falling. This area is associated with the first "wave"
of precipitation that will move northward into Indiana later
tonight. Short term models seem to be too warm ahead of the low as
they show mainly rain as a P-type while mixed rain and ice pellets
are reported throughout Western Tennessee and NE Arkansas. While we
fully expect precipitation to start as rain as it enters Indiana, we
do expect a transition within 1-2 hours of the onset of
precipitation. Paducah, KY transitioned to snow about an hour or two
ahead of what the RAP and NAM show, which is something to take into
account as that could potentially add another inch or two to final
snowfall totals.
ACARS soundings from across the south and Tennessee Valley line up
well with what short term models show, with a warm nose around 700mb
ahead of the system with a pronounced area of below freezing
temperatures below the warm nose supporting a brief period of sleet.
Due to heavier rates, think that evaporative cooling processes have
cooled down the column enough to support more wintry precip rather
than plain rain. Will have to watch P-type with the initial wave as
a brief period of sleet mixing in with rain and snow is possible
before a full transition to snow as observations show.
Overall, forecast is largely on track. Trending snowfall totals up
just slightly across Southern Indiana to account for more wintry
precipitation in downstream observations than what models depict.
Still a little early to determine if the low track will be a little
further north or south of what is currently forecasted. As the low
center becomes better defined, we may be able to tweak the forecast
a bit to account for where the deformation band will set up and
pivot. Confidence remains high for this winter storm event across
Indiana. Stay tuned for more updates throughout the night.
&&
.Short Term...(This evening through Wednesday)
Issued at 135 PM EST Tue Jan 24 2023
Key Points:
WINTER STORM WARNING across much of central Indiana from Late
Tuesday Night through Wednesday Afternoon
* Generally 6-9 inches with highest amounts north and west of
Indianapolis, and less amounts further south and east
* Significant impacts to travel expected Wednesday morning
Discussion:
A significant winter storm remains on track to impact central
Indiana Tuesday night through Wednesday afternoon. Finer grid spaced
models are continuing the idea of a two phased low pressure system,
with greater detail on the timing of each.
Tonight, a closed surface low will approach from the southwest. To
its east, the combination of a strong high over the Atlantic will
create a robust LLJ, topping out around 75kts within its core. This
strong LLJ will provide intense WAA over the Ohio Valley, deepening
the surface pressure out ahead of the already developed surface
cyclone. This region of deepening low pressure, along with strong
vertical ascent will be the primary focus of the initial wave of
precipitation.
Temperatures this afternoon will get into the mid 40s over south
central Indiana, quickly cooling off around dusk. A rapidly
expanding cloud deck will act to limit diurnal cooling however,
creating some uncertainty on temperatures as precipitation enters
Indiana from the SW/S. The current expectation is for temperatures
to be around 36-38 degrees initially, leading to a rain/snow mix.
Temperatures should begin to fall towards freezing with wetbulb
temperatures around 34, aiding in the maintenance of snowflakes as
the fall to the surface. Soundings during this initial wave show a
near isothermal layer well above the ideal DGZ temperatures, of
which will lower SLRs significantly (3-5:1). This should result in a
very dense 1-3 inches south of I-70, with lesser amounts to the
northeast. Timing for this initial wave looks to be between 12am and
6am EST.
The second wave of precipitation will be more associated with the
aforementioned established surface cyclone. This system will be
dynamically aligned with the surface low just to the SE of the 850mb
and 750mb closed lows respectively. This should create an optimal
zone for vertical lift along and north of I-70 where high snowfall
rates are likely during the Wednesday morning hours. The 0C isotherm
should be just south I-70, and will create a rain snow mix,
decreasing SLRs and lowering totals for this region. In far SE
central Indiana, p-type will eventually transition to all rain in
the late morning to afternoon.
High resolution model input has added some clarity to the timing of
heaviest snowfall rates for central Indiana tomorrow. Around 8-9am,
deepening of the 700mb low along with intense isentropic lift out
ahead of the low will create very strong vertical lift, most of which
in a saturated DGZ. This should lead to a prolonged period of at
least 0.5"/hr snowfall rates, along with some locations reaching
1"/hr. This is expected to continue til around 12-1pm, with less
intense snow continuing through the afternoon. In total, the second
wave will proved an additional inch or two over south central
Indiana, with an additional 5-7" likely along and north of the I-70
corridor. Locally higher amounts are also likely within mesoscale
banding within north central Indiana. South central Indiana will
have some snow, but will compact quickly as rain becomes more
predominant. This area is expected to see 0.5"-2" with the second
wave.
Summary:
Snow will begin around midnight Wednesday morning / Late Tuesday
night. Snow ratios will be a bit lower with dense wet snow during
the night. Snow quickly accumulating on the road surfaces is
expected as higher rates / lack of solar radiation will overcome any
residual ground warmth. A couple of inches will likely already be on
the ground by sunrise Wednesday, leading to hazardous driving
conditions. Rain may mix in temporarily near and just south of the
surface low, which will most likely pass just south of I-70. Higher
snowfall rates are likely during the late morning hours on Wednesday
as deformation banding on the northwest side of the low begins to
take shape. Snow begins to wind down late in the afternoon, after 4-
6 PM or so. In totality, Snow totals of 6 to 9 inches are expected,
with the highest amounts north and west of Indianapolis. Lesser
amounts further to the southeast.
&&
.Long Term...(Wednesday night through Tuesday)
Issued at 135 PM EST Tue Jan 24 2023
*Lingering light snow Wednesday night through Friday.
*Next potential system Sunday.
Wednesday Night through Friday.
The bulk of the snow will have wrapped up by Wednesday night as the
surface low pressure moves into Ohio and continues to track to the
northeast. In the aftermath of the low, northwesterly flow aloft
associated with the broad upper level trough will persist through
Friday. Models have also been keying in on an embedded shortwave
that may locally enhance the forcing aloft and bring greater chances
for snow Friday into Friday night.
On Thursday, expect occasional light snow showers and flurries
through the daytime hours with lesser coverage during the overnight.
Over the course of the day around an inch of snow is possible. The
aforementioned shortwave then arrives Friday with the majority of
the snow falling across the northern counties, but confidence
remains low on this system and its impacts.
Saturday through Tuesday.
Flow will then shift to be more zonal and then southwesterly ahead
of the next system that is expected to arrive late Saturday night
into Sunday. Models have had a much more difficult time handling
how a weakening clipper system will interact with a developing
trough across the Gulf states which is leading to a low confidence
event with a lot of moving parts.
Current thoughts are that precipitation is likely Sunday, but
confidence in the precipitation type is very low. Snow is probable
in spots, but think that rain is the more likely precipitation type
for much of the area.
The active pattern we`ve been in looks to continue early next week
with yet another system late Monday through Wednesday. This system
is even more uncertain than the late weekend system, but will
continue to monitor the model ensemble trends.
&&
.Aviation...(00Z TAF Issuance)
Issued at 614 PM EST Tue Jan 24 2023
Impacts:
- MVFR ceilings possible at KLAF this evening
- Rapidly deteriorating conditions overnight as precipitation
spreads in
- Widespread sub-LIFR conditions predawn hours through late
Wednesday with moderate to heavy snow at times
- Gusty winds at times Wednesday
- Mixing with rain expected at KBMG and possible at times at both
KHUF and KIND
Discussion:
...IMPENDING WINTER STORM WILL CAUSE HIGH IMPACT TO AVIATORS...
High level clouds have quickly expanded across central
Indiana late this afternoon and early this evening ahead of the
impending winter storm. Clouds will thicken through the evening and
gradually lower overnight as precipitation approaches. Light
precipitation will first impact KBMG and KHUF near midnight...KIND
shortly after and KLAF later in the overnight. Expect rain to mix
with snow initially with the snow but as deeper forcing combines
with low level temps dropping to near freezing...snow will become
the main precip type from the predawn hours into Wednesday morning.
The heaviest snowfall is expected Wednesday morning into the early
afternoon with lighter precipitation rates thereafter. During the
period of heaviest snowfall...visibilities will likely dip to 1/4 to
1/2SM. Rain will likely mix back in at KBMG as the morning
progresses and may sporadically mix in at KHUF and KIND as well.
Winds will become gusty first from the northeast Wednesday
morning...backing to N/NW into the afternoon as low pressure passes
by to the southeast of the terminals. Ceilings will largely be at
500ft and lower for much of the day with visibilities remaining at 2-
3SM into Wednesday evening as snow becomes more scattered.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 7 PM EST Wednesday for INZ021-028>031-
035>049-051>057-060>065-067.
Winter Weather Advisory until 7 PM EST Wednesday for INZ068>072.
&&
$$
Mesoscale...CM
Short Term...Updike
Long Term...White
Aviation...Ryan
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
831 PM CST Tue Jan 24 2023
.UPDATE...
Issued at 812 PM CST Tue Jan 24 2023
A couple of changes we`ve made to the forecast for tonight/Wednesday
with respect to snow were to significantly increase PoPs and delay
the onset of snow. For the PoPs, it is going to snow, but it will be
light and it may even be somewhat intermittent, but it doesn`t change
the fact that it is going to snow. We have a much better than a
"chance" of snow tomorrow, so updated the PoPs to get a forecast that
actually sounds like it will for sure snow. The other change based
on the early 00z guidance was to delay the snowfall onset, especially
along the I-35 corridor, where sustained light snow is now looking
to hold off until after sunrise Wednesday morning. What hasn`t
changed are the fact that once it starts, the snow will persist
through the whole day on Wednesday for the eastern half of MN and
through at least midnight in western WI. Snowfall expectations
haven`t changed either, with a long duration inch or so expected for
eastern MN and western WI.
&&
.DISCUSSION...(This evening through Tuesday)
Issued at 244 PM CST Tue Jan 24 2023
Key Messages:
- Light snow this evening and overnight will continue throughout the
day tomorrow. A gradual 1/2 to 1 inch of snow is possible through
the end of tomorrow.
- Another round of light snow Thursday into Friday, with further
light accumulations generally up to an inch.
- Warm weather continues through Friday with a significant drop in
temperatures over the weekend and into next week. Lows below zero
and highs in the single digits above zero by Saturday.
Discussion...
The last remnants of the morning fog are slowly mixing
out, with some light returns on radar resulting in nuisance snowfall
mainly in central Minnesota. This is a prelude to the better
snowfall chance which arrives early tomorrow morning via weak to
moderate CVA as a trough swings across the region, resulting in a
clipper-type system that persists through most of Wednesday. This
will be one of those cases where we have persistent stratus and low
clouds, with the energy from the trough introducing scattered bouts
of snowfall where the forcing lines up, with a widely scattered 1/2
to 1 inch total accumulation ending early on Thursday morning. Rates
are not expected to be all that significant, and as such any
roadways which see frequent enough travel should stay relatively
clear just by traffic alone. Forecast soundings continue to show a
relatively weak mixing layer and winds, which should also allow some
patchy fog to set up early in the morning. Otherwise much of the
same through the end of the week with a lack of significant sun,
warmer than normal temperatures in the upper 20s to low 30s (with
climatological normals in the 23-25 range by this point in January),
and rounds of patchy fog.
The second clipper system that moves through Thursday into Friday
will be quick-hitting compared to tonight and tomorrow, with another
1/2 to 1 inch of snow falling within a 6 hour window as opposed to
an 18 hour window, primarily early Friday morning. This is once
again forced by a quick hitting trough axis which swings through,
producing enough forcing to squeeze snow out of the low hanging
cloud cover. The surface response of a fairly strong cold front will
be a minor factor compared to the upper level forcing, mainly
serving as a mechanism to increase the lower level winds and blow
away any remaining fog. Behind the departing system, temperatures
will begin to fall with breezy northwesterly winds persisting only
for a 6 to 12 hour window, however a strengthening upper level ridge
and strong surface high pressure will enter the region, locking in
the cooler air which will eventually filter to the surface. H85
temperatures in the 10 to 14 below zero range within forecast
soundings seems fairly consistent with the temperatures forecast, as
highs generally remain in the single digits above zero from Saturday
through midweek, with lows below zero during this same time frame
as well. Thankfully, compared to previous colder periods (think late
January 2019) winds are not going to be nearly as strong, which
should keep wind chills `warmer` and not even close to record
setting. Rather, this looks to be a fairly standard yearly occurrence
which we end up seeing a couple of times a winter, rather than a
record setting event.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 533 PM CST Tue Jan 24 2023
MVFR cigs have been slow to develop this afternoon, so have delayed
their return several hours. For the snowfall, followed a timing close
to the RAP for bringing snow in, with rates up to 0.2" of an inch per
hour, we`re not looking at significant vis restrictions with this
snow, so have vis pretty steady at 2sm with the -SN. We may see
occasional vsbys down to 1sm, but nothing much lower than that. Once
the snow starts, sites in western MN should only see 6-10 hours of
snow, while eastern MN/western WI should see 20-24 hours of nearly
continuous -SN. As the snow falls and lower levels of the atmo
moisten, we should see cigs drop to between 400 and 800 feet for much
of Wednesday
KMSP...Total snowfall on Wednesday is expected to be up to 1.5". Snow
looks to start between 6z and 10z and once it starts, it likely won`t
stop until around 9z Thursday.
/OUTLOOK FOR KMSP/
Thu...MVFR mrng, VFR aftn. IFR/-SN likely late. Wind NW bcmg SW 5 kts.
Fri...IFR/-SN likely early, bcmg MVFR. Wind NW 15G25 kts.
Sat...VFR. Chc MVFR cigs. Wind N 5-10 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
UPDATE...MPG
DISCUSSION...TDH
AVIATION...MPG