Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/28/23
Area Forecast Discussion
National Weather Service Cleveland OH
938 PM EST Fri Jan 27 2023
.SYNOPSIS...
Low pressure will track through the upper Great Lakes tonight,
extending a warm front across the area quickly followed by a
cold front east across the region. Another area of low pressure
will track northeast through the central Great Lakes region on
Sunday followed by stronger cold front Sunday night. High
pressure will return across the area Monday into Tuesday.
&&
.NEAR TERM /THROUGH SATURDAY/...
9:30 PM Update...
Snow has blossomed along and east of the I-71 and I-77
corridors over the past two hours, so raised PoPs to
categorical over the next couple of hours for NE Ohio and NW PA
as the band of snow showers pushes through. Fairly strong mid-
level isentropic ascent along the warm front has driven this
band of snow showers, but with surface temps of 33 to 35 F,
roads have mainly just been wet. The exception is in the
heaviest bursts where there have been reports of a slushy
coating. Temperatures will further rise over the next few hours
behind the warm front supporting a rain/snow mix or changeover
to rain as the precipitation exits. As the surface low passes
through the northern Great Lakes in the 03 to 07Z timeframe, a
tightening pressure gradient and 850 mb jet of 50-60 knots will
lead to gusty southwest winds behind the warm front. RAP BUFKIT
profiles show a deep boundary layer through the first half of
the night allowing for some of these winds to mix down to the
surface, but the lapse rates are not very steep (somewhat
neutral) which will prevent overly high winds. Still expecting
30-35 knot gusts in SW flow downslope favored areas close to the
lakeshore, as well as on the ridge tops of the Central
Highlands. Once the trailing cold front passes, the boundary
layer depth will decrease behind it, so even though the
temperature profile will begin cooling leading to a steepening
of the lapse rates, the decreasing mixing depth will allow the
winds to begin to diminish. This will occur from west to east in
the roughly 06-09Z timeframe as the cold front passes.
6:30 PM Update...
Updated the forecast to reflect light to moderate snow showers
moving in from west to east a couple of hours faster. This will
bring a light coating of snow and could reduce visibilities to
1/2 to 1 mile at times this evening, but this activity is
actually tied to isentropic ascent along a warm front, so expect
the snow showers to mix with rain after 02 or 03Z. This will
significantly limit any accumulations with most snow melting on
the pavement as temps rise this evening and early tonight. The
rest of the forecast remains on track for tonight.
Original Discussion...
There are two weather systems that we will be impacting the area
over the next 36 hours. The first one will be arriving this
evening associated with a low pressure system tracking north of
the Upper Great Lakes region. A surface low around 991 mb will
be moving across southern Ontario just north of the Great Lakes.
Extending down from the stronger low will be warm front that
will advance across our region this evening quickly followed by
a cold frontal passage later tonight.
Along and ahead of the advancing warm front, scattered areas of
precipitation will accompany this boundary. Temperatures will
be cold enough at the surface and aloft to support wet snow
initially. There may be a brief time window of 2 to 3 hours
where the band of snow could come down at a moderate to heavy
rate. High-res near term model guidance indicate a couple hours
of strong lift and sufficient moisture within the DGZ just
ahead of the warm front. For most of northern Ohio, the snow
will likely mix with or change over to light rain before the
precip ends later this evening. Closer to northwest
Pennsylvania, the precip may stay all snow with this weather
system tonight. Snowfall amounts will be very light between a
healthy dusting of wet snow to around 1 inch possible. Inland
areas of northwest Pennsylvania could see 1 to 2 inches of wet
snow overnight.
Temperatures this evening and tonight will be a little bit of a
"seesaw" effect due to the quick warm frontal passage this
evening and cold front later tonight. Temperatures may drop off
a few degrees early this evening into the lower 30s. The temps
will rise back into the middle and upper 30s with the warm
front. The cold front will knock the temperatures back down
later tonight into the upper 20s and lower 30s.
A brief and weak high pressure area will move in by Saturday
morning with quiet weather during the day. Another fast moving
low pressure system will begin to develop and track northeast
from the Midwest through the southern and central Great Lakes
region by late Saturday night. We have southerly winds
increasing to 15 to 25 mph Saturday night which will bring in
warm air advection. Temperatures will have be steady to a slow
rise Saturday evening and overnight. This time around the
precipitation will be a cold rain with temperatures above
freezing in the middle and upper 30s. The rain chances will
increase to likely POPs from west to east late Saturday night
into early Sunday morning.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
A cold front will be approaching the area from the northwest to
start Sunday, with a weak wave of low pressure developing along the
front through the day and tracking over or just north of Lake Erie
on its way towards the St Lawrence Valley. The front will gradually
sag through the area through the day. We will be ahead of both the
front and a flat shortwave riding along it Sunday morning, so have
likely to categorical (60-80%) POPs for showers (mainly rain) the
first half of the day. We lose the better upper support through the
day, though keep chance POPs going across a good portion of the area
ahead of the advancing front through the afternoon. Am not expecting
any sort of a heavy rain. Compared to a couple of runs ago, models
have trended towards a slower frontal passage on Sunday. Highs on
Sunday will range from the 30s in northwest Ohio where the front
should move through a bit earlier to the low-mid 40s elsewhere. Rain
showers may try mixing with a bit of snow before tapering behind the
front, though with departing upper-level support and not what I`d
characterize as a dramatic temperature drop immediately behind the
front am not expecting any real accumulation potential on Sunday.
Some subtle jet support, along with a very low-amplitude low to mid-
level shortwave trough axis, will move along the front later Sunday
night into Monday morning. This forcing is very modest, but the
European and Canadian models have been hinting at this (and have
spit out some light QPF) for a few runs now. So, continue to have
some slight chance to chance POPs (20-40%) for a bit of snow across
most of the area late Sunday night into Monday morning (can`t rule
out a bit of rain towards Canton and Youngstown depending on how far
the front is able to push through). This feels like a precip chance
that can disappear at a moment`s notice on the models given how
subtle the forcing is, so snow isn`t a given to start Monday yet and
even if it pans out am not expecting any substantial accumulations.
High pressure wedges into the Ohio Valley out of the central US
later Monday so have the POPs gradually departing to the east, sans
the snowbelt counties of far northeast Ohio and northwest PA where
850mb temperatures dipping to -12 to -18C (depending on your model
of choice) and a west/northwest flow could yield some lake effect
snow. The depth of the cold air and amount of moisture to work with
are not great, so am not thinking that heavy lake effect snow is in
the cards for Monday night. Temperatures Sunday night and Monday
will depend on how far the front sags...currently have lows Monday
night ranging from the low to mid 20s in northwest OH to near 30 in
Canton and Mount Vernon, with highs on Monday ranging from the upper
20s in Toledo to the upper 30s in Canton. For now, these numbers are
just what our model blender (NBM) is giving. Lows Monday night
should trend colder, into the 10s for many of us.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
The long term will be colder than average with a frontal boundary
setting up from the lower Mississippi Valley into the Mid Atlantic
states. High pressure and Arctic air will be pressing south into the
central US and trying to wedge east towards the Ohio Valley. Various
pieces of shortwave energy will eject out of the Four Corners region
and attempt to force waves of low pressure to develop and ride along
the frontal boundary.
Models continue to disagree some on the specifics and patterns
featuring energy ejecting out of the Southwest US are notoriously
difficult on the models. That being said, it continues to look like
the two main windows for waves of low pressure to ride by along the
front to our south are Tuesday night into Wednesday, and then
another around Thursday. Models also generally agree that we will
not see one large trough eject out of the west at once, and instead
will see small pieces coming east. With high pressure really
pressing in, this will make it hard for any of these waves to
amplify and track farther north, keeping precipitation chances down.
That said, we do still have slight chance to chance (20-30%) POPs
for snow Tuesday night into Wednesday morning, and again late
Wednesday night and Thursday given a few ensemble members that have
more amplified systems that track farther north. Impression at the
moment is that we`re on the outside looking in regarding potential
for synoptic snowfall, and that substantial trends towards a more
amplified frontal wave would be needed to bring us legitimate snow
potential...hence the low POPs. Arctic air pressing in with a
generally west to northwesterly flow does bring a different story to
the snowbelt, and have a mix of slight chance and chance POPs there
through most of the period. Still much too early to pin down if any
windows of heavier lake effect snow potential exist next week...high
pressure and a very dry airmass may keep a lid of sorts on
things...however, something to monitor over the coming days.
We may actually be below freezing the entire long term period...it
seems that the winter of 2022-2023 is trying to kick a bit.
Overnight lows in the 10s are likely, and if we a night with
stronger radiational cooling some single digits are possible.
&&
.AVIATION /00Z Saturday THROUGH Wednesday/...
A warm front and associated light snow showers are moving
eastward across the region this evening. We have already seen
brief drops in visibility below 1/2 mile at TOL, and expect
these snow showers to continue moving eastward over the next 3
to 5 hours dropping cigs and vis to MVFR. Used TEMPO groups to
try and time shorter periods of IFR visibilities with this
activity this evening. Warmer temperatures as the evening wears
on should allow the snow to mix with rain, so this should
prevent the visibilities from dropping as low as TOL did at the
other TAF sites. Nevertheless, still expect short periods of 1
SM or so as the heavier bursts move through.
Once the snow/rain mix exits east of the region early tonight,
visibilities will return to VFR, but generally MVFR cigs will
prevail with these MVFR cigs lasting for the most part through
Saturday except for maybe some periods of VFR Saturday morning
and again late in the afternoon.
Southwest winds will become gusty later this evening into much
of tonight sustained at 15-20 knots with gusts of 25-30 knots.
MFD, CLE, and ERI could see gusts as high as 30-35 knots. The
winds will subside late tonight and Saturday morning, but ERI
could continue to gust over 25 knots into mid afternoon
Saturday.
Outlook...
Non-VFR likely Saturday night through Sunday with a round of
light rain and or light snow transitioning to all snow Sunday
night. Non- VFR may persist into early next week.
&&
.MARINE...
Strong southwesterly winds will veer more westerly late tonight
into early Saturday as a cold front moves across the lake.
Sustained winds of about 30 knots are in the forecast for
several hours this evening into the overnight over the open
waters...it will be close to a gale, especially towards the east
end of the lake, though at the moment looks to fall just short.
Can not rule out the next shift needing to issue a short-fused
gale warning if winds start to over- perform this evening.
Otherwise, a solid Small Craft Advisory is in effect for all of
our nearshore waters with this gradually dropping off from west
to east through the day Saturday as winds and waves gradually
subside.
The next period of unsettled weather over the lake comes Saturday
night as the front lifts back north as a warm front Saturday
evening, with gusty south-southwest winds ahead of it turning more
northerly late in the day Sunday as it pushes back southeast as a
cold front. Winds ahead of the front may exceed 20 knots, especially
over the open waters. We will monitor for Small Craft Advisory
issuance. A somewhat better chance for a Small Craft Advisory later
Sunday into Monday as winds turn more onshore, though with sustained
winds in the realm of 15 knots or so we shall see if waves can
exceed 4 feet in that timeframe.
Winds will generally be out of a westerly or northerly direction
through the rest of next week as a front stalls to our
south/southeast with high pressure over the Plains our main weather
feature of interest. Winds should not be too strong next week, but
with a mainly onshore flow it doesn`t take much for Small Craft
headlines so can`t rule out needing some at times through the week.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Small Craft Advisory until 4 AM EST Saturday for LEZ142-143.
Small Craft Advisory until 10 AM EST Saturday for LEZ144>147.
Small Craft Advisory until 4 PM EST Saturday for LEZ148-149.
&&
$$
SYNOPSIS...Griffin
NEAR TERM...Garuckas/Griffin
SHORT TERM...Sullivan
LONG TERM...Sullivan
AVIATION...Garuckas
MARINE...Sullivan
Area Forecast Discussion
National Weather Service Cheyenne WY
823 PM MST Fri Jan 27 2023
.UPDATE...
Issued at 820 PM MST Fri Jan 27 2023
Winds have come down...so allowed the existing High Wind Warnings
to expire on time. Not so for the Blizzard Warning at Arlington.
Winds have remained above 35 mph sustained with gusts to the upper
40 mph range. Visibility has stayed down near .1 to .2 miles in
snow and these strong winds. Decided to extend the Blizzard
Warning until 11 PM to be on the safe side. Updates have been
sent.
&&
.SHORT TERM...(Tonight - Sunday Night)
Issued at 248 PM MST Fri Jan 27 2023
The primary forecast concern over the next 24-36
The main forecast challenge over the next 24-36 hours continues to
revolve around a prolonged winter storm poised to bring periods of
accumulating snow to much of the area through Sunday. Strong winds
with gusts 55-60 MPH have been common across the southeast Wyoming
wind corridors today, but should drop off very quickly after about
03z as H7/H85 CAG-CPR gradients should plummet to around 30 meters
during the early evening. Current expiration times of 8 PM MST are
still looking good for Arlington/Vedauwoo. Bordeaux is expected to
be allowed to expire shortly as the wind direction slowly turns to
northwesterly and becomes less favorable for warning-criteria wind
gusts. Blizzard conditions have persisted through the afternoon in
WYZ110 (Arlington/Elk Mountain) with visibilities as low as 1/8 to
1/4 mile frequently being observed at multiple WYDOT sensors along
w/ near whiteout conditions on area webcams. A Blizzard Warning is
in effect until 8 PM MST this evening. At that point, winds should
diminish below the required threshold, but additional accumulating
snow and some blowing snow will persist through Saturday night, at
least. For the time being, have opted to add a Winter Wx Adzy from
8 PM MST tonight until 11 PM MST Saturday. However, the next shift
may opt to upgrade to a Winter Storm Warning if surface obs & web-
cams continue to indicate poor visibilities after 8 PM.
The greatest impacts will continue to be felt across the Snowies &
Sierra Madres with SNOTELs suggesting that 1 to 3 feet of snow has
already fallen above 9000 feet. Total accumulations of 3 to 5 feet
appear very likely due to extremely favorable orographics, as well
as deep mid and upper-level moisture. Accumulating snow will begin
to spread across the lower elevations of southeast Wyoming and the
western Nebraska Panhandle tonight through Saturday, with a second
wave likely on Sunday. Confidence in snowfall amounts remains very
low as the pattern remains more of an open-wave w/ modest moisture
and a prolonged period of low-level upslope flow. WV imagery leads
to some concerns that we may not see significant accumulations, as
substantial dry slotting is evident upstream. High-res models such
as the HRRR have trended much lower with snowfall amounts, several
inches lower than previous forecasts. NBM v4.1 has also trended in
this direction with less than a 10% chance of 6+ inches across the
entire CWA outside of the mountains. Main change was to trend snow
amounts lower, incorporating the latest high-res guidance into the
previous forecast and newer blends. Given a broad range of amounts
in the ensembles, confidence is exceptionally low. No changes were
made to inherited headlines for this reason. Also, given this snow
will come in multiple waves, overall impacts may be limited enough
that a Winter Weather Advisory is appropriate even if some locales
technically exceed the numerical criteria for a Warning. Expect to
see current Warnings/Advisories eventually be extended another 12-
24 hours into Sunday night, but given yet another drastic shift in
model data as we approach a winter weather event, have decided not
to make any changes at this time.
.LONG TERM...(Monday - Friday)
Issued at 248 PM MST Fri Jan 27 2023
Key Impact Messages:
1) Snow slowly coming to end early Monday morning after prolonged
weekend event. Likely residual travel impacts ongoing late weekend
into early next week. Drier period ahead after early Monday to late
week.
2) Brutally cold Monday into Tuesday Morning with negative 20 to
negative 30 wind chills both mornings. Wind chills will not warm
above zero until Tuesday afternoon for many locations. Wind Chill
Advisories will be likely.
3) Increasing wind Tuesday into Thursday that could lead to blowing
snow impacts of reduced visibilities, new drifts, and travel impacts
after this weekend`s snowfall.
Weather Discussion: Biggest story for the extended will be the
brutal cold temperatures and wind chills once again across WY and NE
as an arctic airmass settles into the region. H7 temperatures will
drop to -18C to -25C Monday resulting in high temperatures only in
the single positive digits. Lows both Monday morning and Tuesday
morning are forecast to be in the negative single digits to negative
teens. Wind chills will be dangerously cold in the -20 to -30 range.
Ironically, the warmest locations will be in the mountains near zero
for lows as the dense airmass dams up against the mountains with an
inversion above. Temperatures will warm more Tuesday afternoon as
westerly WNW zonal flow aids warm air advection from the Pacific NW
vs. north Canada but still remain below freezing.
The switch to WNW to West flow Tuesday however, will bring tighter
height gradients and both in-house AI and ensemble members highlight
elevated winds across wind prone zones and Converse County. These
might be just under High Wind Warning criteria based on current
projections but winds of 40-50mph will be likely. High Plains will
also be breezy Tuesday with at least 25-35 mph. Combination of
recent snow, and likely how dry it will be while increasing its
"blowability" - could lead to blowing snow impacts Tuesday. Reduced
visibilities and drifting back on to area roads could be an issue.
By mid-week to late week, ensembles and dprog/dT of deterministic
models highlight continued dry period with slowly moderating
temperatures. Highs should reach above freezing for select spots in
the High Plains Thursday and more so into next Friday. Another
period of elevated Winds Thursday with a dry shortwave passage.
WY/NE will likely be on the eastern edge of a developing H5 ridge
over the western CONUS per model consensus late week. Evolution
confidence decreases into next weekend but a general dry period with
more limited impacts outside of elevated to high wind appears
favored mid- to late-next week into next weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 420 PM MST Fri Jan 27 2023
Wyoming TAFS...Continued deteriorated conditions will prevail at
Rawlins with areas of snow and blowing snow along with gusty winds
through mid morning Saturday producing IFR conditions.
Visibilities and ceilings will continue to lower at Laramie with
increasing coverage of snow showers overnight and through the
Saturday daylight hours.
VFR conditions at Cheyenne will prevail overnight, before
deteriorating to MVFR after 12Z Saturday as a cold frontal passage
and wind direction switch produces increasing coverage of upslope
cloudiness.
Nebraska TAFS...Visibilities and ceilings will continue to worsen
at Chadron and Alliance overnight with IFR developing in numerous
snow showers. Wind directions will also switch to north and
northeast behind a cold frontal passage late tonight.
The cold frontal passage will affect Scottsbluff and Sidney a bit
later, between 12Z and 14Z, with lowering ceilings to MVFR and a
wind direction switch to north and northeast, with increasing snow
cover at Scottsbluff Saturday afternoon.
&&
.FIRE WEATHER...
Issued at 202 AM MST Fri Jan 27 2023
Prolonged period of widespread snowfall is expected today and
continue through the weekend. With additional new snow on top of
an already existing snowpack, fire weather concerns will be low
over the next few days. Winds will be gusty across SE Wyoming
today with strong winds across the wind prone areas and higher
elevations. By next week, temperatures will drop to well below
average.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Weather Advisory until 11 PM MST Saturday for WYZ101-102-
104>109-111-113.
Winter Storm Warning until 11 PM MST Saturday for WYZ103-112-114.
Blizzard Warning until 11 PM MST this evening for WYZ110.
Winter Weather Advisory until 11 PM MST Saturday for WYZ110.
NE...Winter Weather Advisory until 11 PM MST Saturday for NEZ002-003-
095-096.
&&
$$
UPDATE...GCC
SHORT TERM...CLH
LONG TERM...JSA
AVIATION...RUBIN
FIRE WEATHER...AW
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
715 PM EST Fri Jan 27 2023
.AVIATION...
A strong cold front extending south from low pressure in northern
Ontario is powering snow showers across southern Lower MI. Multiple
pockets of this activity remain capable of LIFR restriction with a
few brief drops to VLIFR 1/4SM S+ until the front sweeps past the
terminal corridor by midnight. Low level cold advection then keeps
the boundary layer mixed and wind gusts elevated through tonight
until the pressure gradient relaxes Saturday morning. Upstream
observations will be monitored for signs of freezing drizzle that
remains possible as mid level dry air surges in post front. Ceiling
is otherwise expected to drift up toward the MVFR/VFR threshold
during the late night and morning as a narrow and weak high pressure
ridge builds in between low pressure systems, the next of which will
be apparent moving in from the west during Saturday afternoon. VFR
under virga transitions to IFR in light snow by late in the day and
mainly north of PTK.
For DTW... A few more hours of snow showers remain, each bringing a
dusting of accumulation, until a cold front sweeps through toward
midnight. Ceiling averages MVFR during this time while visibility
varies widely across the range of categories. SW wind gusting around
25 knots diminishes late tonight while clouds drift up toward
MVFR/VFR threshold. A return MVFR is expected in the morning.
DTW THRESHOLD PROBABILITIES...
* High for ceiling 5000 feet or less tonight and Saturday.
&&
.PREV DISCUSSION...
Issued at 318 PM EST Fri Jan 27 2023
DISCUSSION...
Fast moving clipper system currently seen moving through the western
Great Lakes reaches the westernmost portions of the CWA late this
afternoon with light snow overspreading the eastern areas by early
evening. As is typical with continental originating systems,
moisture is lacking with specific humidities at or below 2 g/kg.
This in combination with main PVA residing well to the north of Lake
Superior caps accumulation potential to around 1 inch across SE MI.
Snow quickly tapers off from west to east between 03-06Z early
tonight. Other noteworthy impact with be gusty conditions late this
afternoon into early tonight as a 50-60kt LLJ works across southern
lower MI leading to winds peaking around 30-35mph. These winds
gradually diminish through the overnight period as the LLJ shifts
over Ontario.
Worth noting there is some potential patchy drizzle signal in
forecast soundings during this tapering down window where
strengthening subsidence results in top-down drying lowering
saturation heights out of the DGZ to -10C or less. The main question
is whether any potential drizzle stays liquid or freezes as the
elevated warm frontal passage supports gradual warming of surface
temps this evening to around the freezing mark before the cold front
crosses after midnight. Based on guidance trends, areas north of M-59
have the greatest chance to stay under 32F and potentially see some
freezing drizzle late this evening. That said, impacts should be
lower than typical given it will be falling onto top of freshly
fallen snow.
Focus then shifts to a second, potentially more impactful system
this weekend. W-E oriented baroclinic zone lingering over the
southern lower MI that develops in the wake of the clipper allows a
sheared shortwave ejecting out of the northern Rockies to track into
the area by late Saturday afternoon. Lead edge of this wave causes a
tilting in the temperature orientation to SW-NE as well as spurring
the development of isentropic ascent. Spatial placement of this
initial ascent still carries some uncertainty as its tied to the
exact track of the surface reflection, which still carries
significant uncertainty itself, however currently trends favor areas
north of M-59. Going more into the uncertainty in the surface
reflection track, considerable spread continues to exist across both
high-res and coarser model runs from last night and this morning.
The NAM12 and 12Z HRRR are the northerly outliers in the track north
of I-69 leading to rain over most the area and snow confined to the
northernmost areas. Conversely the GFS and Canadian (NH and RGEM),
while showing slight northward trends, are still the southerly
outliers confining mix/all rain to south of I-94. The
ECMWF/NAM3km/ICON/UKMET/RAP/ARW/FV3 all advertise something in
between with a mix line draped somewhere between the I-94 to I-69
corridors.
In general, trends have held for a gradual shift north of the
primary deformation axis/heaviest snow with roughly around the I-69
corridor toward the Tri-Cities/Thumb generally favored amongst the
majority of deterministic solutions (which the running forecast will
highlight). Given a healthy amount of accompanying moisture
(specific humidities still progged to be at least 2-3 g/kg, perhaps
approaching 4 g/kg) and longer duration (between 03-18Z Sunday) of
persistent deformation/fgen forcing, a ribbon of 3-5" (isolated 6")
is expected associated with the primary deformation axis, with 1-4"
possible elsewhere. Areas along and south of I-94 could struggle to
get accumulations if northerly trends continue leading to a mostly
all rain event. Would expect models to start to come into better
agreement in next couple cycles as the shortwave reaches the CONUS
and is better sampled.
Baroclinic zone sags south of the area by early Monday as arctic
high pressure establishes itself over the Plains and Great Lakes.
This airmass brings the coldest air of the season so far as 850mb
temps fall below -16C resulting in highs in the low 20s to upper
teens and single digit lows through the midweek period.
MARINE...
A strong low-level jet has built in over the Great Lakes ahead of an
approaching low pressure system which is low centered just north of
Lake Superior. This stronger jet has brought stronger wind gusts
down to the surface and will bring a period of gales that will last
through the late evening over Lake Huron, Saginaw Bay, and Lake St.
Clair. Trajectory of the low pressure system will allow a cold front
to sweep across the Great Lakes late tonight into tomorrow morning.
Wind direction will veer from southwest to northwest following the
passage of the front which will prolong gale potential across
northern Lake Huron. As a result, the Gale Warning will last well
into tomorrow morning given the idealized northwest fetch. Freezing
spray will also be likely across northern Lake Huron after the
passage of this front.
Light snow fills in over the Great Lakes through the evening ahead
of the front. Wind speeds will diminish throughout tomorrow morning
once the low pressure fully vacates the region, with a secondary low
pressure system then filling in over the northern Ohio Valley late
Saturday into Sunday. This will bring another chance for rain or
snow for the greater portion of the Great Lakes, outside of far
northern Lake Huron. Wind speeds are expected to stay below gales
with this storm system, but Small Craft Advisories may be possible
for portions of the Lake Huron shoreline as wave heights increase
once direction backs to the northeast.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Gale Warning until 10 PM EST this evening for LHZ363-421-422-
441>443-462>464.
Gale Warning until 7 AM EST Saturday for LHZ361-362.
Lake St Clair...Gale Warning until 10 PM EST this evening for LCZ460.
Michigan waters of Lake Erie...Small Craft Advisory until 10 PM EST this evening for LEZ444.
&&
$$
AVIATION.....BT
DISCUSSION...KDK
MARINE.......AM
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
555 PM CST Fri Jan 27 2023
...New AVIATION...
.SHORT TERM...
(Tonight through Saturday night)
Issued at 137 PM CST Fri Jan 27 2023
Surface high pressure continues to slide eastward early this
afternoon, as mid-level cloud cover remains situated over South-
Central Texas. This mid-level cloud cover is mainly a result of
continued pacific moisture streaming in overhead from the southwest.
Some filtered sunshine is expected this afternoon, but generally
north of the I-10 corridor. Southward, mid-level clouds will remain
in place for the foreseeable future as low level moisture from sfc-
850 mb layer will rapidly increase this evening through the
overnight hours. Latest RAP guidance depicts rapid moisture return
overnight, with drizzle, reduced visibilities, and isolated rain
showers developing from the Coastal Plains and northward into the I-
35 Corridor.
Expect lingering on and off showers to be possible Saturday evening
into Sunday morning, ahead of the next cold front, which will more
than likely make it`s presence felt in the long term forecast. Ahead
of that, moisture return will continue in earnest, with a rather
mild night Saturday, as temperatures may struggle to drop below the
60 degree mark over the I-35 Corridor and points east.
&&
.LONG TERM...
(Sunday through Friday)
Issued at 137 PM CST Fri Jan 27 2023
Precipitation chances continue for the start of the period, mainly
from the Hill Country and locations east as a front to the north
slowly moves across the area during the day. Most likely will see
only scattered showers, but a few isolated thunderstorms will be
possible due to the ample moisture, shear, and lift, especially in
the Coastal Plains. Lapse rates will steepen throughout the day and
there could be a a few storms along the front that become strong
enough to develop hail. Could see a decent temperature gradient
across the area on Sunday due to the front draping across south-
central Texas, with temperatures in the 60s to around 70 north of
the front, and temperatures in the 70s south of it, with the
dividing line basically splitting the CWA from north to south at this
time. Rain chances should be out of the area by Sunday evening, but
dry weather will be short-lived with precipitation chances returning
Monday afternoon and lingering through much of the week.
The main culprit for these renewed chances is increased isentropic
lift which lingers through mid-week. Damp and cloudy conditions will
persist through Wednesday with temperatures decreasing each day. By
Wednesday, widespread 40s to 50s are expected for high temperatures.
With the continued cloud cover, lows will generally stay above
freezing for most locations, with the exception in areas of the Hill
Country and some locations in the southern Edwards Plateau early
Wednesday and Thursday mornings. Right now ensemble guidance has
about a 5 percent chance for freezing rain across these areas, with
the majority of guidance keeping any frozen precipitation north of
our area.
An upper level trough approaches the area on Wednesday which will
bring the most robust push for moderate rain across the CWA. Total
forecast amounts Wednesday into Thursday morning range from 0.25-
1.00", highest over the Hill Country and northern I-35 corridor. A
few thunderstorms may also be possible. Dry weather returns by
Thursday afternoon with clearing skies. Cold overnight lows Thursday
night into Friday with another cool day anticipated Friday.
&&
.AVIATION...
(00Z TAFS)
Issued at 541 PM CST Fri Jan 27 2023
Sharp moisture gradient will be migrating inland this evening. MFR
skies should last through mid evening at DRT and AUS, but SAT/SSF
should see a lowering to MVFR cigs in the 02Z to 04Z range as light
radar echoes signaling light drizzle builds northward up the I-37
corridor. Light rain and drizzle should become prevailing overnight
into late morning which should help lower cigs into IFR levels after
midnight and a short period of LIFR conditions possible near and just
after daybreak along I-35. IFR skies should linger into the rest of
the morning along I-35, while some improvement to MVFR might occur at
DRT before noon. DRT should get back to VFR in the early afternoon,
but IFR skies may hold in place all day at AUS. In between this range
of conditions, SAT/SSF should see mostly MVFR cigs in the afternoon
and potential to see a few hours of VFR in the late afternoon or
early evening. A slightly unstable SW flow pattern aloft could
potentially lead to more pessimistic conditions in the later periods.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 48 67 59 67 / 20 20 20 40
Austin Bergstrom Intl Airport 47 67 59 68 / 20 20 20 40
New Braunfels Muni Airport 48 68 59 71 / 30 20 10 30
Burnet Muni Airport 45 65 53 62 / 10 10 10 30
Del Rio Intl Airport 48 69 52 78 / 0 0 0 10
Georgetown Muni Airport 46 66 57 65 / 10 20 20 30
Hondo Muni Airport 48 66 55 74 / 10 10 0 20
San Marcos Muni Airport 47 68 59 70 / 30 20 20 40
La Grange - Fayette Regional 49 69 62 68 / 30 30 30 60
San Antonio Intl Airport 48 66 59 71 / 30 20 10 30
Stinson Muni Airport 51 68 61 73 / 30 20 10 30
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term...18
Long-Term...17
Aviation...18
Area Forecast Discussion
National Weather Service Goodland KS
442 PM MST Fri Jan 27 2023
.SHORT TERM...(This evening through Monday night)
Issued at 253 PM MST Fri Jan 27 2023
Across the Tri State region this afternoon, sunny skies early on
have now given way to a veil of high cloud pushing in from the west.
These clouds have put a damper on daytime highs in some locales
despite southerly winds across the area. Currently, a range from the
mid 30s to mid 40s is occurring.
The current RAP40 500 mb analysis in tandem with mid level water
vapor imagery is showing northwest flow aloft over the area, with a
shortwave pushing through the central Rockies. The veil of clouds
ahead of it is what is putting a damper of temps for the area this
afternoon.
At the surface, the latest HRRR has a lee-side trough over the
eastern slopes, which is forecasted to move east of the Front Range
into the Plains region by 12z Saturday. The cold front associated
with this continues to be the main wx focus for the region starting
this weekend into next week.
Southerly flow currently will begin to back to the west overnight
and eventually to the north-northeast by Saturday morning. The
latest 850mb temps with the expected arctic air surge for the cwa
are ranging -14c to -19c. While this will not be the core of the
coldest air expected, these numbers, combined with area snowpack,
will drop overnight lows below zero after tonight. The caveat for
these temperatures will be the expected low cloud/moisture shield.
This could either help or hinder temps in the short term, but
overall, very cold area-wide.
Expecting the airmass over the region to become very dry with this
arctic air. Guidance showing persistent low level moisture
available, but above 700-500 mb, dry. This will pose an issue for
producing snow initially over the weekend. The "seeder-feeder"
mechanism will not be present, thus opening the area to potential
flurries with a possible mix of freezing fog/drizzle. Have
introduced some mainly in Colorado, but will need to be monitored
for further expansion east. At the peak of the arctic air over the
cwa, snow ratios of 15 to 20/1 will mean any snow that falls will be
very fluffy and not amount to much.
If the low clouds remain, persistent flurries are possible. GFS/NAM
showing a second shortwave late in the weekend into next Monday that
may enhance snow potential. Overall, any snow totals will range an
inch or less over a 36-48 hr period.
Also, with these cold temps staying pat with latest guidance, feel
more confident on issuing a second Wind Chill Advisory for 00z-16z
Monday for the entire cwa. The first one 00z-16z Sunday remains
intact with only some downward revision to expected wind chill
numbers, now closer to -20F. If later guidance suggests otherwise,
these may be needed to be upgraded to warnings.
For temps, with the arctic front pushing south into the region
during the early/mid morning hours Saturday, early highs ranging
from the 20s north to around 30F south are expected. These numbers
will continue to drop through the day. By Sunday, upper single
numbers above zero into the mid teens are expected. Slightly lower
numbers expected during the day Monday with mainly single numbers
above zero. Lower teens in far east/south locales.
Biggest impacts with this arctic surge will be felt during the
overnight hours. Tonight, lows mid teens to mid 20s will give way to
mainly single numbers below zero for Saturday and Sunday nights. For
Monday night, single numbers below zero are expected as well.
With these cold overnight and early morning lows, wind chill
readings are expected to range from -15F to -24F, prompting the
current Wind Chill Advisories this weekend.
.LONG TERM...(Tuesday through Friday)
Issued at 201 PM MST Fri Jan 27 2023
For the long term period, main focus remains on the cold weather to
start the period. The remainder of the period is forecasted to
slowly moderate.
For Tuesday & Wednesday, the morning hours are still forecasted to
have advisory level wind chills with temperatures near zero and
winds around 10 mph. The days are forecasted to warm slightly higher
compared to the previous days with highs generally in the teens and
twenties as the main part of the upper trough and surface high
pressure move off to the east. The main thing that would keep
temperatures cooler would be if the cut-off upper low and surface
low to the south west moves far enough north to bring cloud cover to
the area in which single digits and teens would be more likely. With
drier air forecasted to be over the area, snow would be unlikely
short of an isolated flurry.
Thursday and beyond has some uncertainty tied to the track and
evolution off the upper cut-off low, but generally should be warmer.
Guidance suggests an upper level ridge will move in from the west
which should help temperatures warm, especially with dry conditions
in the forecast.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 432 PM MST Fri Jan 27 2023
KGLD expects to start the 00Z TAF period under VFR conditions with
southerly winds around 11 kts that veer through the night until
becoming westerly at 08Z. By 16Z, KGLD winds turn northerly around
12G18 kts before MVFR conditions come to the terminal at 21Z as a
broken cloud ceiling develops at 1500 ft with north-
northeasterly winds around 14 kts.
KMCK starts with VFR conditions as well with southerly winds
around 6 kts that increase to around 10 kts at 05Z when southerly LLWS
begins at 2 kft. By 07Z, KMCK sees LLWS end as the winds become
variable around 6 kts. At 17Z, KMCK winds become northerly at
13G20 kts as IFR conditions begin with an overcast cloud ceiling
moves in at 700 ft. By 19Z, wind at KMCK become north-
northeasterly with snow chances in the vicinity beginning at 21Z.
Exact timing of the northerly wind shift at the terminals is
still uncertain with the cold frontal passage associated with a
surface low passing the CWA, but it does look to be between
somewhere between 12-18Z. Will continue to monitor and update
forecast when details become clearer. There`s also chances for
precipitation at both terminals towards the end of the 00Z TAF
period and beyond, so will watch for any changes there as well.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Wind Chill Advisory from 5 PM MST /6 PM CST/ Saturday to 9 AM
MST /10 AM CST/ Sunday for KSZ001>004-013>016-027>029-041-
042.
Wind Chill Advisory from 5 PM MST /6 PM CST/ Sunday to 9 AM MST
/10 AM CST/ Monday for KSZ001>004-013>016-027>029-041-042.
CO...Wind Chill Advisory from 5 PM Saturday to 9 AM MST Sunday for
COZ090>092.
Wind Chill Advisory from 5 PM Sunday to 9 AM MST Monday for
COZ090>092.
NE...Wind Chill Advisory from 5 PM MST /6 PM CST/ Saturday to 9 AM
MST /10 AM CST/ Sunday for NEZ079>081.
Wind Chill Advisory from 5 PM MST /6 PM CST/ Sunday to 9 AM MST
/10 AM CST/ Monday for NEZ079>081.
&&
$$
SHORT TERM...JN
LONG TERM...KAK
AVIATION...076
...Updated Forecast Discussion...
.DISCUSSION...
Issued at 553 PM CST Fri Jan 27 2023
Key Messages:
- Band of snow to lead to hazardous travel conditions in
northeast NE into west-central IA late tonight and Saturday.
- Significantly colder next week with dangerous wind chills of
-15 to -30 degrees likely (greater than 80% chance).
Tonight through Saturday:
Afternoon radar imagery showed the beginnings of our band of snow
across western SD and western NE with a shortwave and surface low
passing just east of the Rockies. A surface cold front was draped
northwest to southeast across Nebraska and will continue to push
south as we go through the night and into Saturday. To the north
of the surface boundary, low to mid-level frontogenesis will
strengthen and lead to development of the aforementioned band of
snow, generally centered on the NE/SD border and extending
eastward into northwest IA. In addition, RAP guidance reveals a
frontogenesis/frontolysis "couplet" for several hours Saturday
morning. This lends credence to the 50%+ probabilities of 1 inch
per hour snowfall rates from the HREF near the NE/SD border.
The main questions that remain are 1) how long does the heaviest
snow last and 2) where exactly does the band set up . Latest short
term guidance suggests the strongest frontogenesis starts to
taper off/push east of the forecast area as early as 9 to 10 AM
Saturday, though model soundings indicate at least some light snow
could linger in these areas much of the day. In addition, snow
onset has trended a bit later, so overall duration may be a touch
shorter, but with the aforementioned forcing and snowfall rates,
amounts within the band have not changed much. As far as
placement, guidance today has trended a little farther north,
placing the center of the heaviest band more into SD, but still
looking like 6 to 9 inches in Knox and Cedar counties with amounts
tapering off fairly quickly as you go south (e.g. currently
expecting less than 1 inch near and south of a Columbus to Omaha
line). One final concern is that with a lighter, fluffier snow
expected, strong northeasterly winds will lead to blowing and
drifting snow through the day on Saturday, even after the falling
snow comes to an end (sometime Saturday afternoon). Hazardous
travel conditions are expected in these areas that receive the
heaviest snow.
Sunday through Thursday:
With Saturday`s snow squarely in the rear-view mirror, the main
forecast concern will turn to well-below normal temperatures to
start next week. Minimum wind chill values Sunday through
Wednesday mornings will need or at least threaten Wind Chill
Advisory headlines. With the main axis of the upper-level jet
stream being south of the forecast area, a bitterly cold airmass
and high pressure will dominate most of the area with the low
point temperature-wise being Sunday with gradual improvement
through the mid-to-late week. Highs Sunday are expected to muster
single- digit to low-teen values while morning wind chills tank to
-27 to
-15 degrees for much of the area.
On the bright side of things, due to the vicinity surface highs
and relatively weak pressure gradient expected during this time
period, wind speeds are not expected to be overly high, and should
stay below 20 mph aside from gusts to 25 mph early Tuesday. After
Sunday`s area-wide cold, morning wind chill values of below -20
degrees will be relegated to areas north of a line from Columbus
to Harlan through Wednesday. By Thursday, mid-level heights begin
increasing from the west thanks to a building ridge over the
western CONUS to go along with incrementally increasing
temperatures to let Falls City reach above freezing Thursday
afternoon. The rest of the forecast area will have to wait for
Friday/next weekend to climb out of the freezer.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 524 PM CST Fri Jan 27 2023
VFR conditions to prevail early in the TAF before a band of snow
moves in from the north. Heaviest snow looks to remain north of
the TAF sites, but still expect heavy enough snow for IFR
conditions shortly after onset at KOFK. KOMA is on the southern
edge of snow, so kept only 6SM -SN mention there through 12Z for
now, though can`t rule out some flurries through much of Saturday.
Model consensus keeps KLNK dry through the period, though a few
pieces of guidance hint at a wintry mix from around 7Z to 10Z.
Otherwise, expect IFR ceilings to set in at KOMA and KLNK Saturday
morning with some improvement to MVFR possible toward the very end
of the period. Winds will go from easterly to northeasterly,
gusting 20 to 30 kts and possibly lead to some lingering blowing
snow at KOFK through the period.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Winter Weather Advisory from 9 PM this evening to 6 PM CST
Saturday for NEZ015-033-034.
Winter Storm Warning until 6 PM CST Saturday for NEZ011-012.
Winter Weather Advisory until 6 PM CST Saturday for NEZ016>018-
031-032.
IA...Winter Weather Advisory from 9 PM this evening to 6 PM CST
Saturday for IAZ043.
&&
$$
DISCUSSION...CA/Petersen
AVIATION...CA