Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/26/21
AREA FORECAST DISCUSSION
National Weather Service Albany NY
1026 PM EST Thu Nov 25 2021
.SYNOPSIS...
Expect a cloudy and dry Thanksgiving with temperatures
turning a little milder. A cold front will bring a period of light
rain and rain/snow mix for the higher terrain tonight before
noticeably colder and windy conditions ensue by midday tomorrow.
Lake effect and upslope snow showers continue tomorrow afternoon
into Friday night resulting in light to moderate snow accumulations
mainly for elevations 1000ft and above. However, brief snow showers
cannot be rule out even in valley areas.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Rain tracking through eastern NY and western New England
now and will exit through the early morning hours before there
is a break in the precipitation. Clouds and light precipitation
will prevent temperatures from falling too much more through
the night. Just minor adjustments to temperatures and sky cover
through the night. Previous discussion has more details and is
below...
PREVIOUS DISCUSSION:
Cloudy and seasonably mild today as an upper level ridge slides
into New England resulting in weak warm air advection thanks to south-
southwesterly flow through the column. Due to thickening and
lowering clouds impeding insolation and a subsidence inversion
that is limiting boundary layer mixing, temperatures today will
not deviate too much from climatology with most areas near or a
few degrees above normal. Expecting highs in the low to mid 40s
for most areas with upper 40s for the mid-Hudson Valley and NW
CT areas and the southwest Adirondacks struggling to climb out
of the 30s. Otherwise, dry conditions will persist through
sunset.
Tonight, warm air advection increases resulting in a brief period
of light showers. These showers should impact areas west of the
Hudson by 21 - 03 UTC with areas from the Hudson River into
western New England observing showers from 03 - 09 UTC. Due to
weak overall forcing, QPF amounts will be low amounting to
around a tenth of an inch or less. P-type will be mainly rain or
rain/snow mix but higher terrain areas in the southwest
Adirondacks, southern Greens and Taconics could experience some
brief sleet or freezing rain at times given near freezing
surface temperatures but weak WAA maintaining slightly milder
temperatures aloft. Any wintry mix should be brief with minimal
impacts. Due to southwest flow, cloud coverage and light
showers, expecting temperature to be steady overnight, remaining
in the low to mid 30s.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/...
Winter Weather Advisory for Hamilton and northern Herkimer
County 7am Friday to 7am Saturday...
Winter Weather Advisory for Bennington County, VT and eastern
Rensselaer County, NY from 10am Friday to 7am Saturday...
The main cold front associated with our parent trough will
approach eastern NY and western New England tomorrow morning
with a period of showers ahead of the leading edge of the
incoming cold air mass overspreading the area by 09 - 15 UTC.
Mild air initially will favor rain for most areas with rain/snow
mix in the higher terrain; however, once the wind shift boundary
pushes through and winds shift quickly to the west or west-
northwest, a surge of cold air will infiltrate the region and
whatever showers are left could transition to rain/snow mix.
Total QPF amounts from the morning period of showers still
look light generally 0.10 - 0.20" but given better low level
forcing, expect a steadier period of rain compared to what falls
Thursday night.
The leading edge of the incoming cold air mass overspreads the
entire region by 15 - 18 UTC with gusty winds rapidly ensuing as
our parent trough becomes negatively tilted. Expect west to
northwest winds to become sustained between 10 to 20mph with
gusts 25 to 35mph. Gusts up to 40mph are possible in the higher
terrain. The strong winds will usher in a cold air mass
characterized by 850hPa dropping to -5C to
-8C. As a result, surface temperatures should suffer, reaching
their daily maximum values in the mid to upper 30s (low 40s in
the mid- Hudson Valley and NW CT) near or before 18 UTC and then
should decrease through the afternoon.
The strong cold air advection and favorable west-northwest fetch
across the relatively mild Lake Ontario waters will also invoke
a strong lake effect response as inversion heights rise above
5000ft. Lake effect snow showers likely impact our western and
southern Adirondack areas Friday morning through Friday
afternoon with snow ratios increasing throughout the day up to
12 - 14:1. Total snowfall amounts here expected to range 3 to 5
inches with up to 5 - 7 inches in the chimney of Herkimer
County. We issued a Winter Weather Advisory to alert residents
for this lake effect event. Strong winds combined with
increasingly fluffy snow may also reduce visibility and lead to
blowing snow.
As surface temperatures drop midday into the afternoon,
ongoing rain/snow showers that reach into the eastern
Catskills, Schoharie County, Helderbergs and Mohawk Valley could
transition to mainly snow showers leading to coatings to one
inch of snow. Best chance for accumulating snow likely in the
afternoon when cold enough air moves in aloft that even surface
temperatures near or slightly above freezing could support minor
accumulations.
In addition to lake effect snow showers, the strong west-
northwest winds plus moist cyclonic flow behind the negatively
tilted parent trough overhead will likely result in an
impressive upslope snow event for the southern Greens and
Rensselaer Plateau. Froude numbers are less than one through 00
UTC Saturday which suggests that the highest snowfall amounts
should occur just upwind of the spine of the Greens which is
where we expect 3 to 6 inches with locally higher amounts up to
8 - 10 inches. Lower elevations of Bennington County should
still experience 1 to 3 inches of snow but there will be a
significant increase in snow amounts and rapidly changing
weather conditions as elevation increases. Moderate to even
briefly heavy snow is expected with snowfall rates up to 1 inch
per hour possible at times in the higher terrain. We issued a
Winter Weather Advisory for Bennington County in VT and eastern
Rensselaer County in NY but the higher terrain areas above
1500ft could see warning level snow amounts in excess of 6 - 7
inches. Due to to localized nature and lower population areas
here, we did not issue a winter storm warning. Initially, SLRs
should be slightly below climatology (less than 10:1) as
boundary layer temperatures will be mild and the DGZ zone is
above 700hPa. This could lead to a wet snow initially. However,
as the cold air mass overspreads the region and temperatures
drop through the afternoon, SLRs should improve reaching ~12:1
by 00 UTC Saturday. Even still, high QPF amounts and strong
forcing for ascent from the terrain should result in impressive
snow amounts. As SLRs increase and winds remain gusty, reduced
visibility is possible.
As the parent trough exits into New England Friday evening,
elongated vorticity maxima extending into eastern NY in its wake
combined with ongoing cold air advection could support snow
showers continuing into the late afternoon and early evening
hours. In fact, high res guidance such as the HRRR hints at the
potential for the northwest winds and sufficient lake enhanced moisture
to allow snow showers to reach even into valley areas, possibly
even the Capital District. There remain uncertainty on exactly
where any snow showers could impact as these should be isolated
to scattered at best but sfc temperatures near and after dark
will be cold enough to support a quick coating up to a few
tenths of snow depending on the intensity of any snow showers.
Upslope and lake effect snow showers wind down overnight,
especially after 06 UTC Saturday. Gusty winds continue so
temperatures will likely not become as cold as they could given
the chilly air mass in place. Still, expect temperatures to fall
into the low to mid 20s.
Breezy conditions linger into Saturday as our mature cyclone
escapes into the Canadian Maritimes dropping to sub-980hPa with
high pressure in the mid-Atlantic building northeastward. Skies
will remain mostly cloudy as northwest flow maintains a moisture
fetch off the lakes. Temperatures will also be colder than
normal given the ongoing cold air advection regime with highs
only rising into the low to mid 30s with the higher terrain
remaining below freezing.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Our upper-level feature will depart Saturday night with high
pressure squeezing into the region. This will result in mainly dry
and cold conditions with lows in the teens and 20s. It could turn
out a bit colder if winds can go calm for enough of a period of
time.
Attention then turns to our next feature for later Sunday into
Monday. Long range guidance (GFS/ECMWF/Canadian) suggest a slightly
different upper-level and surface pattern when compared to yesterday
but all show a similar new solution. So, while run-to-run
consistency is not completely present, the agreement amongst the
guidance when things change remains similar. This suite of runs show
an approaching upper-level shortwave from the Ohio Valley followed
by a more potent upper-level trough from the upper Great Lakes
(albeit more progressive). At the surface, an area of low pressure
will track westward into western New York and Pennsylvania,
weakening over the Appalachians in the process, then transfer its
energy to a coastal low (positioned farther east than yesterday`s
runs).
These new solutions prevent much of our area from receiving impacts
from the coastal low. However, the presence of warm advection and
isentropic lift from the weakening low to our west would still
result in an area of precipitation (mostly in the form of snow).
Areas closer to the I-90 corridor may be more favored for steadier
precipitation than far northern and southern areas (area of best
lift and low-level convergence). As a result, we increased pops from
the NBM to high chance and low likely in these areas. Still too soon
to determine exact snow amounts, but a light accumulation is
possible for all areas. In the wake of this system, some wrap around
and/or lake-enhanced snow showers will be possible on Monday but
looks to be short lived as upper-level heights rise. High
temperatures both Sunday and Monday will range from the 20s to lower
30s in the higher elevations to the mid-30s to lower 40s in the
valleys.
The remainder of the period has lower confidence as models show all
different solutions, though they indicate a continued west to
northwest upper-level flow and a series of upper-level shortwaves
passing near or through the region, which could lead to periods of
rain/snow showers. It is uncertain which days have the better
chances, so generally ran with NBM pops which led to slight chance
to low chance pops at times. It will continue to be on the chilly
side with highs mainly in the mid-20s to lower 30s in the higher
elevations and mid-30s to lower 40s in the valleys with lows mainly
in the teens and 20s.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
Through 00z/Sat...VFR conditions will start the TAF period, but a
period of light rain will push across the terminals between 02z-
07z/Fri in which a gradual lowering to MVFR cigs is anticipated.
Vsbys should be mainly VFR as precipitation will be light.
Thereafter, a break in precipitation is expected but mainly MVFR
cigs are anticipated for the remainder of the overnight (however,
some rises to VFR are possible at this time, especially at KPOU).
A cold front will push across the terminals later Friday morning
which will bring another round of rainfall to all sites. Cigs and
vsbys look to be MVFR at this time. Rain showers look to continue
through the afternoon (especially at KALB/KGFL/KPSF) though the
arrival of colder air could allow for an eventual mix or changeover
to snow showers. Highest confidence for a changeover to snow is at
KPSF (where IFR vsbys are likely) with moderate confidence of at
least a rain/snow mix at KALB/KGFL (with MVFR or maybe IFR vsbys).
There is lower confidence in visibility reduction precipitation at
KPOU due to downsloping so will only include VCSH at this time.
Ceilings Friday afternoon look to range from high end MVFR to low
end VFR.
Wind will be calm or light out of the south for the majority of
tonight, then turn out of the west to southwest at 5-10 kt Friday
morning. In the wake of the cold front, wind will shift to the west
Friday afternoon and increase to 12-16 kt with gusts 25-30 kt
(highest at KALB/KPSF).
Outlook...
Friday Night: High Operational Impact. Breezy. Likely SHSN.
Saturday: Low Operational Impact. Breezy. NO SIG WX.
Saturday Night: No Operational Impact. NO SIG WX.
Sunday: Moderate Operational Impact. Chance of SN.
Sunday Night: Moderate Operational Impact. Likely SN.
Monday: Low Operational Impact. Slight Chance of SHSN.
Monday Night: Low Operational Impact. NO SIG WX.
Tuesday: Low Operational Impact. Slight Chance of SHRA...SHSN.
&&
.HYDROLOGY...
Rain showers tonight into tomorrow morning will result in about
0.10 - 0.20" of liquid precipitation. Then, lake effect and
upslope snow showers will follow for Friday afternoon into
Friday night. While 3 to 6 inches with up to 8 to 10 inches of
snow is expected in the higher terrain areas of the southern
Greens, southern and western Adirondacks, and Rensselaer
Plateau, this will not impact rivers.
For details on specific area rivers and lakes, including
observed and forecast river stages and lake elevations, please
visit the Advanced Hydrologic Prediction Service /AHPS/ graphs
on our website.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Winter Weather Advisory from 10 AM Friday to 7 AM EST Saturday
for NYZ054.
Winter Weather Advisory from 7 AM Friday to 7 AM EST Saturday
for NYZ032-033.
MA...None.
VT...Winter Weather Advisory from 10 AM Friday to 7 AM EST Saturday
for VTZ013.
&&
$$
SYNOPSIS...Speciale
NEAR TERM...NAS/Speciale
SHORT TERM...Speciale
LONG TERM...Rathbun
AVIATION...Rathbun
HYDROLOGY...Speciale
Area Forecast Discussion
National Weather Service Binghamton NY
922 PM EST Thu Nov 25 2021
.SYNOPSIS...
A period of rain is expected into the overnight as a cold front
approaches. These rain showers will transition to snow showers
Friday morning as colder air moves into the region. Lake effect
snow and gusty winds are expected Friday afternoon through early
Saturday afternoon. We are watching a system that could bring a
period of widespread light snow late Saturday night into
Sunday.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
915 PM Update...
Just tweaked POPs to reflect on-going radar trends. Didn`t make
any changes to snowfall forecasts as colder air works across NY
and PA late tonight and Friday. Rain will turn to light snow
and the lake effect snow showers will set up Friday into Friday
night. We have winter weather advisories for a large part of
north central NY with 2"-6" of snow forecast. It looks like the
highest amounts will be in the higher terrain south of the
Thruway from Southern Cayuga Co to Cortland Co. Southern
Onondaga and southern Madison counties. These areas will see
colder temperatures and an earlier change-over hence more will
accumulate. Wind gusts likely will peak late afternoon/early
evening Friday at 30-40 mph in most areas. In areas where snow
will be falling considerable blowing and drifting snow will
occur. With a west-northwest flow the southern tier of NY east
of Owego into the Catskills likely will see 1-2" of snow in the
higher terrain, possibly 3-4" in the higher terrain of
Catskills. In northeast PA, the higher terrain in Susquehanna
and Wayne Counties and even down to southern Lackawanna Counties
likely will have a covering of snow to as much as a few inches
over Elk Mountain at the highest terrain of northeast PA. The
rest of the forecast area will see falling temperatures Friday
and gusty winds. It will feel a lot like winter.
00z Namnest, 00Z HRRR suggests a little less snow falls that
what we have advertised at present. Model soundings show that
the inversion is just below the dendretic snow growth layer. In
any event, winter weather advsiory looks on track for now. More
guidance will be needed to make any adjustments to snow
amounts.
545 PM Update... Did a quick update to account for light rain
showers that have developed across areas east of I-81 in central
NY/northeast PA. Also bumped POPs up to likely in north central
NY based on latest radar trends. Otherwise, going forecast for
lake effect snow and transition looks on track based on latest
guidance.
330 PM Update
Just some scattered light rain showers around under mostly
cloudy skies through the early evening hours.
Periods of rain then move in from the west by 6-9 PM and
continue on and off into the overnight. There will be some
breaks in the steady rain, with just patchy drizzle at times.
The rain will then begin to mix with wet snow, first over the
higher elevations by around 4-7 AM. Overnight lows will be in
the 30s. Colder air aloft begins to filter into the region just
before daybreak ,as 850 mb temperatures reach -5C at sunrise.
No major changes to the forecast late tonight through Friday
night; just minor tweaks to match the latest guidance and WPC.
Temperatures start off in the mid to upper 30s at daybreak
Friday, but fall into the low/mid-30s by midday and upper 20s to
lower 30s in the afternoon.
Confidence has grown for an advisory level lake effect/upslope
snow event starting daybreak Friday, peaking Friday afternoon
and evening before winding down Saturday morning. Therefore,
continued the Winter Weather Advisory for Oneida, Onondaga,
Madison, Cortland and Southern Cayuga counties. Expecting 2-5
inches for Oneida County, with 3-6" and locally higher amounts
for the other advisory counties. On the edge of the advisory
area, expect 1-3 with locally up to 4 inches for parts of
Seneca, Tompkins and Chenango counties. Could see eventually
needed to add Tompkins and/or Chenango into the advisory if snow
amounts and confidence increase even slightly in future updates.
Further south for the Southern Tier east into the Catskills
there will be a period of snow showers Friday into Friday night
with a dusting to 2" most probable...isolated 3 inches amounts
possible for northern Tioga, Otsego and Delaware Counties
(especially higher elevations). For the Chemung Valley region
down into NE PA there will just be some flurries or scattered
snow showers around late afternoon into the evening, with
locally up to 1 inch possible.
Northwest winds will be gusting 30-40 mph Friday afternoon and
evening, which will combine with falling temperatures and snow
to produce areas of blowing snow. Expect potentially hazardous
winter travel conditions Friday into Friday night across much of
CNY, but especially in the winter weather advisory areas.
Some drier air in the mid levels of the atmosphere gradually
works into the area from the west later Friday night. This will
decrease the coverage of snow showers after midnight, but a lake
effect band should continue on the cold northwest flow off of
Lake Ontario and perhaps the Finger Lakes. Initially there is
sufficient, deep moisture through the DGZ but late at night this
begins to decrease. The best ascent is forecast to be below the
DGZ much of the time based off the 12Z NAM soundings at
Syracuse, but there should still be enough lift into the DGZ for
dendrites to form...especially in the favored upslope locations.
Snow to liquid ratios should increase to between 12-15:1
overnight...although the strong winds and blowing snow may put a
bit of a damper on any higher ratio potential. Outside of the
main lake effect areas expect partly cloudy skies with isolated
flurries possible in NE PA. It remains breezy overnight with
northwest winds 10-20 mph. Cold with lows in the upper 10s to
mid-20s.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
350 PM Update...
Lake effect snow will taper off on Saturday morning, though
models such as the NAM12 and CMC Regional suggest it may be a
little stubborn in letting up over parts of Southern
Onondaga/Seneca and northern Cortland Counties, as is often the
case. But snowfall rates will rapidly diminish by mid morning,
and the area should be precip- free by midday. Cold northwest
winds will remain breezy, and while some clearing is likely in
the afternoon, especially south of the Thruway and into NEPA,
highs will be stuck in the upper-20s to lower 30s, with the
Wyoming Valley perhaps squeezing out mid-30s.
Meanwhile, an Alberta clipper will be moving into the western Great
Lakes, with a secondary shortwave trough right on its heels. The
initial shortwave and attendant surface low will reach Lake Erie
late Saturday night, with weak isentropic lift spreading from SW to
NE across western PA into western NY. It`ll be running into a very
dry airmass across NY and PA, but top-down moistening and modest low
level moisture advection should be enough to get some light snow to
reach the surface by early Sunday morning, especially west of I-81.
We may see a brief lull as isentropic lift weakens later in the
morning, but the aforementioned secondary shortwave trough will
quickly catch up to our clipper, allowing the weak surface low
to deepen (slightly), and leading to more widespread light snow
showers across the area through the afternoon and evening hours.
The snow showers will tend to favor areas along and north of
the surface low track, so the highest PoPs will generally be in
NY state and into the northern tier of PA. Snowfall rates will
generally be light, but an isolated heavier squall is not out of
the question, particularly as colder air aloft (H7 temps of -15
or colder) push into the area late in the afternoon, steepening
lapse rates. Early projections suggest 1-3 inches will fall
over a broad area by Monday morning, favoring the higher terrain
of the Allegheny Plateau.
On the back side of the clipper late Sunday night into much of
Monday, expect another transition to lake effect snow, again
favoring the Seneca/Onondaga/Cortland county area given NW flow
and a Lake Huron connection.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
350 PM Update
Yet another clipper system looks to sweep through the area
Monday night into Tuesday. Initially, winds will shift, cutting
off the Lake Huron connection and shifting the focus for lake
effect snow northwards. This second clipper will be a little
wanting for moisture, and significant accumulation looks
unlikely at this point.
Somewhat quieter and milder weather is expected in the wake of
this system, though a weak system may try to pass well to our
north on Wednesday night, with high pressure building in for
Thursday.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
Cold front approaching from the west will usher in MVFR
ceilings after 03Z this evening with light rain on the front
end, changing to a mix of rain/snow between 06-10Z overnight
and then eventually to all snow after 12Z. Fuel alternate
required to MVFR ceilings are expected as this front moves
through overnight.
IFR restrictions are likely at SYR and RME, along with BLSN
after 15Z. The snow showers at ITH and BGM will subside slightly
after 14Z and then ramp up again after 18Z with some IFR
vsbys/cigs possible. For ELM and AVP, once the rain showers
(possibly mixed with some wet snow showers) move out by 12-15Z,
expect a return to low-end VFR or high-end MVFR CIGS and
unrestricted vsbys with periods of light snow showers.
Southwest winds 5 to 10 kt this evening will become west then
west- northwest after the cold frontal passage early Friday
morning and increase to 10-20 kts with gusts to 25 to 30 kts
late Friday morning and through the afternoon.
Outlook...
Friday night through Saturday morning...Potential lake effect
snow showers with restrictions, especially SYR, ITH, BGM
terminals otherwise VFR.
Saturday afternoon into evening...Conditions improve to VFR all
areas as lake effect snow ends.
Late Saturday night through Monday...Another system developing
to our southwest will bring a period of light to moderate snow
with associated restrictions to much of the forecast area.
Tuesday...Continued chances for snow showers and associated
restrictions as a weak wave combines with lake effect.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...Winter Weather Advisory from 5 AM Friday to 9 AM EST Saturday
for NYZ009-017-018-036-037-044.
&&
$$
SYNOPSIS...DJN/MJM
NEAR TERM...DJN/MJM
SHORT TERM...MPH
LONG TERM...MPH
AVIATION...BJT/MJM
Area Forecast Discussion
National Weather Service Cleveland OH
1011 PM EST Thu Nov 25 2021
.SYNOPSIS...
A cold front located from near Erie to Canton late this evening
will continue to move east across Pennsylvania overnight A
trough will linger over the area through Saturday morning. High
pressure then briefly builds over the area Saturday afternoon
and evening before another area of low pressure moves over the
area Sunday.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
Latest forecast appears to be on track. No changes to the
headlines. However still slight concern we will need to nudge
snow amounts up slightly across Geauga County. Until we start
seeing the bands of lake effect snow starting to develop it is
difficult to jump on this.
Colder air continues to move across the CWA with all locations
seeing temperatures under 0 C at 850 MB. Have been watching the
850mb temperatures from the HRRR closely with a change to snow
occurring across Michigan as they drop into the -6 C to -8 C
range. The -6 C isotherm at 850 mb is just entering the western
CWA. So expect to see a gradual change to snow with it reaching
the central CWA about 0530Z and NW PA around 07Z. It still
appears that the heaviest lake effect snow will occur from 10Z
to 20Z, mostly over NW PA.
Previous Discussion...
Currently a low pressure system is situated over the central Great
Lakes, extending a cold front southwest across western Ohio. This
cold front will continue to push east across the area this afternoon
into the evening, allowing for rain showers to continue to diminish
over the area. Simultaneously, the low pressure is also expected to
move east and intensify over the eastern Great Lakes tonight, which
is when the forecast becomes much more tricky with a shift from the
synoptic rain, to a rain/snow mix, and then ultimately lake effect
snow.
As the cold front departs the area between 00Z and 06Z Friday, a
surge of cold air is expected to be ushered in by northwesterly
winds across the area, transitioning all precipitation to snow near
06Z. Temperatures at 850-mb will become much colder at -10 to -12C,
which coupled with Lake Erie water temperatures in the central and
eastern basins still in the mid to upper 40s, will allow for
moderate lake induced instability of 350-400 J/kg to develop.
Equilibrium levels are expected to steadily increase to near 10kft
by Friday morning, before gradually decreasing into Friday evening.
With conditions over the lake primed for LES development, models are
also suggesting an area of enhanced convergence along the lakeshore,
spanning from eastern Cuyahoga County through Erie County, PA,
through Friday morning. All of these factors, coupled with the moist
airmass in place, will definitely result in LES for much of the OH
and PA snowbelts, with the highest amounts expected in Erie County,
PA. As a result, a Lake Effect Snow Warning has been issued for
southern Erie County and a Winter Weather Advisory has been issued
for northern Erie County and Crawford County. These go into effect
at 1AM Friday and will continue through 7AM Saturday. This upgrade
was a resulting of increasing confidence of over 8 inches of snow
falling across Erie and LES persisting longer than previously
forecast. Inland areas of the OH snowbelt can expect to see 1-3
inches of snowfall.
There are however, many variables in play that could result in
higher/lower snowfall totals. One of the biggest factors that will
impact snowfall totals is how quickly the dry airmass moves across
the area. Current models continue to trend towards keeping the moist
airmass in place longer, which would keep an ideal LES environment
in play longer than previous models had suggested, resulting in
the forecasted snow totals. If dry air moves in faster, then
totals will likely be less. The timing of the drier airmass will
also be key in any Lake Huron connection that models now
suggest may occur Friday afternoon. If the dry air is slower to
move in, these bands may be able to reach NW PA before fizzling
out, which may result in slightly higher snowfall totals
locally. Aside from the moisture content of the airmass, the
strong winds will also play an important role in where the snow
will fall. With this forecast, wind gusts from the northwest of
30 to 35 mph are possible Friday morning into the afternoon,
locally higher along the lakeshore. These winds may result in
the highest snowfall accumulations shifting a bit south.
Confidence in when or where this may occur is low so opted to
keep highest totals in eastern Erie County, but something that
will need to be monitored in the upcoming forecast updates.
Finally, it is uncertain how quickly snow will begin to
accumulate overnight. With temperatures this afternoon remaining
in the 40s and a wet surface from all the rain, initial
snowfall will likely melt on contact. However, if heavy
snowbands with 1 in/hr rates develop quickly, snow will likely
accumulate much quicker.
The forecast through Friday night is very complex and dependent
on an number of factors aligning at the right times. The key
take away is that heavy lake effect snow showers are expected
across Erie County which will result in hazardous travel.
Motorists should use caution as roads will become snow covered
and slick, with the possibility of quickly changing
visibilities.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Several pieces of energy will move through the northwest flow across
the Great Lakes Region over the weekend, carving out a trough across
New England by Monday. At the surface, a ridge will build east
across the Great Lakes region on Saturday with any lingering snow
tapering off fairly quickly as we continue to dry from the
west. Most of the area will be dry until precipitation develops
from west to east Saturday night as isentropic ascent increases
ahead of the leading shortwave. Precipitation may begin
initially as rain if it begins prior to 00Z Sunday, but should
mostly transition over to a period of light snow. There is some
question as to where the axis of precipitation develops along
the 850-700mb front so that may need some minor adjustments.
Temperatures at 925mb do warm aloft overnight reaching around 0C
up to the Route 30 corridor and a mix back to rain is possible
across the south.
Surface low pressure will meander east across Lake Erie on Sunday. A
second piece of energy will dig into the upper trough across the
Great Lakes on Sunday with energy shifting to the East Coast by
Monday morning. The track of the low will be a factor to watch over
the weekend and will effect how much snow/precipitation falls during
the daytime hours on Sunday. The NAM brings drier air a little
farther north on Sunday morning while the other models maintain
precipitation across NE Ohio/NW Pennsylvania a little longer.
Later in the day, all models show lake enhanced precipitation
filling back in as NW flow accompanied by deeper moisture
develops behind the upper trough. Not expecting much of a
temperatures rise during the day on Sunday as cold advection
kicks back in and lowered high temperatures by a degree or two
across the east. Additional light to moderate snow will resume
across the snowbelt Sunday afternoon into Sunday night before we
lose deeper moisture on Monday. Lowered Snow accumulations over
the weekend will likely range from around an inch across
portions of NW and Central Ohio to 2-6" across the snowbelt with
highest amounts in NW Pennsylvania.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
Another ridge of high pressure will slide east across the area on
Monday bringing an end to the lake effect. During the extended we
will see a series of waves move through the NW flow aloft and will
hold onto low chance pops across the snowbelt region. Temperatures
will tend to remain below normal with highs in the mid 30s to low
40s.
&&
.AVIATION /00Z Friday THROUGH Tuesday/...
Cold front was located from Sandusky to Findlay at 00Z. Rain
and drizzle have filled in ahead of the front with IFR/LIFR
conditions. These conditions will persist as the cold front
moves to the east through the evening. Winds increase quickly in
the wake of the cold front as winds shift to the west and
northwest. Southwest winds of 6-10 knots are expected ahead of
the cold front. As the front passes west to northwest winds
increase to 12-16 knots with gusts 25-30 knots possible.
Strongest gusts should occur near the lakeshore, especially from
10Z-17Z.
There may be a lull in the precipitation across NW OH in the
wake of the cold front but believe some scattered snow showers
arrive after 03Z along with ceilings lowering to MVFR levels.
Further east where the winds flow off of Lake Erie ceilings
should not improve above MVFR levels in the wake of the front.
As snow showers and a few heavier bands of lake effect snow
develop expect ceilings and visibilities to drop to IFR levels.
The most significant impacts will likely be at KERI and maybe
KYNG late tonight into Friday morning. Will need to watch KCLE
and KCAK closely as northwest winds could direct scattered
heavier lake effect snow showers over the terminals.
All locations should see ceilings gradually lift Friday
afternoon with VFR across NW OH. Locations downwind of the lake
will see variable MVFR/IFR conditions in snow showers but there
could be breaks of VFR conditions for KMFD, KCLE, KCAK for late
afternoon into the evening.
Outlook...Non-VFR possible in snow Friday through Sunday in
Northeast Ohio and northwest Pennsylvania.
&&
.MARINE...
Low pressure will move from southern Ontario into Quebec tonight,
pulling a cold front across Lake Erie. Winds will abruptly shift to
the northwest behind the front and increase to 30 knots overnight
and continuing into Friday morning on the central and eastern basin
of the lake. There is a short window where we may be close to gale
force winds, mainly from 9 AM-1 PM and can not rule out the need to
issue a brief Gale Warning for the mid-section of Lake Erie west of
Long Point towards Erie Pennsylvania. The strong winds will lead to
waves of 6-10 feet on Friday. Small Craft Advisories remain in
effect for all nearshore waters through at least Friday afternoon,
continuing for areas east of the Lake Erie Islands through Friday
night/Saturday. Improving conditions are expected on Saturday as a
ridge builds east across the lake.
Another area of low pressure will deepen as it tracks east across
Lake Erie on Sunday. Winds will increase out of the west/northwest
in the wake of the low and another round of Small Craft Advisories
will be needed Sunday through Monday.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...Winter Weather Advisory from 1 AM Friday to 7 AM EST Saturday
for PAZ001-003.
Lake Effect Snow Warning from 1 AM Friday to 7 AM EST Saturday
for PAZ002.
MARINE...Small Craft Advisory until 10 AM EST Saturday for LEZ146>149.
Small Craft Advisory until 4 PM EST Friday for LEZ142-143.
Small Craft Advisory until 4 AM EST Saturday for LEZ144-145.
&&
$$
SYNOPSIS...Campbell
NEAR TERM...Campbell/MM
SHORT TERM...KEC
LONG TERM...KEC
AVIATION...MM
MARINE...KEC
Area Forecast Discussion
National Weather Service Wilmington NC
1043 PM EST Thu Nov 25 2021
.SYNOPSIS...
Showers are likely late tonight into early Friday as a cold
front moves across the area. The front will move farther
offshore Friday morning bringing cooler weather to the area by
Saturday. A mainly dry cold front will bring a reinforcing shot
of cold air into the area the first half of the upcoming week.
&&
.UPDATE...
Some tweaks to the clouds and pcpn, basically delaying it by a
1-2 hrs based on latest and trends of both Satellite and Mosaic
88D imagery as well as HRRR model imagery. Have tweaked hrly
late evening thru overnight temps up by a degree or 2 based
on latest Obs trends and the active boundary layer SW winds.
But overall theme of the fcst remains, ie. the sfc high
retreating offshore and the approach and passage of a cold front
overnight into daylight Fri morning. No change to the SCA or the
NC Counties Fire Danger Statements. Will need to look into SC
Forestry with CAE and see if a SPS is required for our SC
Counties.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
High pressure will sink south and then shift eastward as a cold
front approaches from the west tonight. Winds will shift a bit
more SW this evening and should increase enough to keep the
boundary layer from decoupling. Overall, we will remain in weak
WAA ahead of front with a non-diurnal temp curve leading to
overnight lows close to 50 most places. Moisture ahead of the
front will move through rather rapidly and remain rather narrow,
confined to a few hour window reaching the I-95 corridor after
midnight and clearing the coast by mid morning. Expect a quick
window of pcp with most places picking up less than a tenth of
an inch of rainfall. Skies should clear rapidly. Gusty NW winds
and CAA behind the front will make for a cooler day on Friday
with increasing sunshine only pushing temps about 5 to 10
degrees higher from morning lows, with highs in the 50s most
places with gusty NW winds making it feel cooler.
Deep N to NW flow will continue into Fri night with continued
CAA as dry high pressure builds into the area. The 850 temps
will drop about 10 degrees from this evening to Sat morning
with overnight lows down below freezing most places.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
The mid level pattern will more or less be from the
west, northwest though the period as the forecast remains
dry. At the surface high pressure will meander across the area
from west to east with a dry front moving across late. Cool
highs Saturday in the lower to middle 50s will warm into the 60s
Sunday ahead of the next front with a bit of warm air
advection. Morning lows will generally be in the middle 30s.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
The mid level west to northwest flow will continue
into early next week relaxing toward the end of the period
with some mixed signals on the extent of the warm up.
Operational guidance is more bullish on highs approaching 70 by
midweek with a more reserved trend with other guidance.
Maintained the more muted approach for now with the forecast
remaining dry as well.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
VFR through the evening hours with SCT/BKN thin to opaque
cirrus. A cold front will move fairly swiftly from west to
east across the Carolinas during the pre-dawn Fri hrs and
exiting the Carolina Coasts early to mid daytime Fri morning.
Potential for brief period of MVFR associated with scattered
showers and ceilings. VFR to dominate by by midday with gusty
NW winds thru the aftn.
Extended Outlook...VFR and high pressure dominates Fri night
into Sun. Brief MVFR possible Sun night from a CFP. VFR
and high pressure Mon thru Tue.
&&
.MARINE...
Through Friday Night...
High pressure will drop south and east tonight as a cold front
moves in from the west. Winds will increase as gradient tightens
with the approach of a cold front through tonight. The winds
will shift to the west and then NW as front moves through early
Fri. Winds should reach up to 20 to 25 kts tonight with gusts up
to 30 kts into Fri morning pushing seas up to 3 to 5 ft peaking
just near or under 6 ft Fri morning before shifting to the NW.
The offshore flow will keep greatest seas farther offshore.
Gusty NW flow will diminish slowly through Fri falling below SCA
thresholds by Fri aftn. Winds will remain NW to N through Fri
night with seas down to 2 to 4 ft most waters.
Saturday through Tuesday...
Light wind fields Saturday will become better defined from
the southwest into early Sunday as high pressure drifts
offshore and a cold front approaches from the northwest. This
flow will increase to a maximum of 15-20 knots late Sunday
before a wind shift associated with the front occurs. This flow
will peak at 15-20 knots as well and diminish through Tuesday
while becoming more northeast. Very modest seas of around two
feet will increase with the winds to a range of 2-4 feet.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...Small Craft Advisory until 1 PM EST Friday for AMZ250-252-254-
256.
&&
$$
SYNOPSIS...ILM
UPDATE...DCH
NEAR TERM...RGZ
SHORT TERM...SHK
LONG TERM...SHK/SRP
AVIATION...DCH
MARINE...RGZ/SHK
Area Forecast Discussion
National Weather Service Lincoln IL
737 PM CST Thu Nov 25 2021
.SYNOPSIS...
Issued at 329 PM CST Thu Nov 25 2021
A cold night is in store across central Illinois...as clearing
skies and diminishing winds allow low temperatures to bottom out
in the teens.
&&
.UPDATE...
Issued at 737 PM CST Thu Nov 25 2021
A back edge to extensive low cloud cover has been rapidly pushing
eastward this evening, having reached I-57 by 730 pm. Clear skies
and diminishing winds overnight associated with an approaching
surface high pressure ridge will allow for cold temperatures by
morning. Expected lows ranging from 14 in Galesburg to 21 in
Lawrenceville look good. Updates this evening have been mainly to
speed up clearing around the I-57 corridor.
&&
.SHORT TERM...(This evening through Friday)
ISSUED AT 329 PM CST Thu Nov 25 2021
21z/3pm satellite imagery shows clearing line along/west of the
Illinois River. Based on timing tools and latest HRRR forecast, it
appears skies will clear along the I-55 corridor within the next
2-3 hours, then further east to the Indiana border by mid-evening.
Northwesterly winds are currently gusting 25-30mph: however, as
high pressure builds eastward, winds will slowly decrease to less
than 10mph overnight. Due to clearing skies and diminishing winds,
low temperatures will drop into the teens.
.LONG TERM...(Friday night through Thursday)
ISSUED AT 329 PM CST Thu Nov 25 2021
Quiet weather will be on tap throughout the extended, with a
couple of weak disturbances embedded within the prevailing
northwesterly flow pattern potentially bringing light precip.
After a partly to mostly sunny day with highs in the 30s on
Friday, the first wave will track through the Midwest on Saturday.
12z Nov 25 models have come into fairly good agreement with the
track/timing of this feature...with consensus showing surface low
pressure skirting just north of central Illinois. As a result, the
bulk of the precip associated with the low will fall further north
across Wisconsin/Michigan, with just a few light rain showers
expected further south toward the I-74 corridor. Will include
slight chance PoPs across the northern half of the KILX CWA
accordingly.
After the Saturday wave passes, temps will cool into the lower to
middle 40s for Sunday...before quickly rebounding back into the
upper 40s and lower 50s by Monday and Tuesday. A second short-wave
trough will traverse the Midwest by mid-week: however, model
solutions vary significantly. Have therefore opted to maintain a
dry forecast until better model consistency is achieved.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 521 PM CST Thu Nov 25 2021
MVFR cigs remain east of a KDEC-KBMI line, with SKC west of this
line. This clearing will move steadily eastward this evening,
resulting in VFR conditions across the central IL terminals by
01Z-02Z. Although scattered mid and high clouds will return toward
sunrise, VFR conditions will continue through the 24-h TAF
forecast period. Winds NW 10-15 kts with gusts around 20 kts at
00Z, with gusts dropping off rapidly this evening and winds
steadily decreasing overnight. A shift to S winds is expected by
18Z-20Z, with speeds remaining under 10 kts.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...37
SYNOPSIS...Barnes
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...37
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
931 PM EST Thu Nov 25 2021
.UPDATE...
Issued at 931 PM EST THU NOV 25 2021
A few minor adjustments to the forecast in the T/Td grids and the
PoPs overnight. Have updated the T/Td grids with the latest
observations and trends for the next few hours. Have lowered the
PoPs in the northern and western counties based on radar returns
being quite weak as the cold front approaches. Updates have been
sent.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 505 PM EST THU NOV 25 2021
21Z sfc analysis shows a cold front steadily pushing toward
central Kentucky with a band of cold rain showers preceding it.
This rain has dropped temperatures into the mid to upper 40s here
in the east while bringing the dewpoints up to the lower 40s.
Winds are still mainly from the southwest through the JKL CWA at
around 10 mph with some gusts to near 20 mph.
The models are in terrific agreement aloft through the short term
portion of the forecast. They all depict a digging trough
sharpening over the Ohio Valley tonight dragging a band of energy
through the state coincident with some larger height falls. While
the heights will start to rebound on Friday a final energy stream
will pass through the JKL CWA that afternoon in fast northwest
flow. Given the small model spread have used the NBM grids as the
starting point for the forecast, with significant inclusions of
the HRRR and RAP low level moisture and instability parameters.
Sensible weather will feature a classic post frontal rain to snow
situation for eastern Kentucky tonight as colder air undercuts the
departing pcpn. As such, we look for a light dusting possible most
places, but up to an inch conceivable for locations above 2000
feet where a few roads may be impacted with slick patches later
tonight into Friday morning. While the northwest flow will be the
main culprit activating the lingering low level moisture for snow
showers there is a decent shot for some enhancement from Lake
Michigan per the high-res near term models. For this reason, kept
slightly higher PoPs and the possibility of thicker dustings in
the northeast portion of the CWA, along with some moderate cold
regime instability noted mainly in our northeast counties. This
could lead to more cellular snow showers for a time Friday morning
and perhaps even some reports of graupel. On account of the
potential for some accumulating snow on the higher elevations
roads an SPS was issued for our three easternmost counties. Friday
night will likely feature a very cold night with a decent ridge
to valley temperature split showing up given the beginning of
return flow.
Only made minor adjustments to the temperatures from the NBM
mainly for terrain distinctions on Friday night. As for PoPs,
beefed them up for our typical post frontal upslope flow regime
along with the higher CAMs guidance.
.LONG TERM...(Saturday through Thursday)
Issued at 428 PM EST THU NOV 25 2021
The period begins with our area under northwesterly flow aloft
roughly between a large low centered over New England and a short
wave over the Northern Plains. This short wave moves southeastward
across the Mississippi Valley Saturday, ending up over the Ohio
Valley by late Saturday night/early Sunday, all while supporting a
similarly placed low at the surface. An attached warm front
initially lifts through the area by Saturday evening, before the
cold front is eventually dragged through during the
afternoon/early evening on Sunday. Expect impacts to be restricted
mainly to just increasing cloud cover through the evening for
most areas. The best moisture will be confined to areas further
north within the Ohio Valley and will limit the precip chances for
most on Sunday, outside of possibly a few areas in our far north.
However, some models suggest enough lingering moisture in the low
levels behind the front that would keep some sprinkles from being
entirely ruled out, particularly for portions of our far east,
especially as low level lapse rates steepen later in the afternoon
heading into the evening and flow becomes more
westerly/northwesterly. Better return flow Saturday will help
temperatures reach higher than Friday, but highs still remain
slightly below normal in the upper 40s to low 50s. Temperatures
dip only marginally Saturday night ahead of the front, bottoming
out only in the mid 30s.
Moving into the workweek, our area remains under northwest flow
aloft as stagnant troughing remains across much of the eastern
CONUS. A few passing waves move through the flow throughout the
remainder of the period, though models show some slight
disagreements over finer details, leading to a bit of uncertainty
around precip chances, particularly late Monday into early
Tuesday. However, these disturbances are generally lacking in
deeper moisture over our area and don`t appear to have much impact
other than periods of increased cloud cover. The broad troughing
will help to keep temperatures late in the weekend through the
first part of the week averaging below normal. Temperatures then
moderate for the middle of the week, ending up slightly above
normal by then end of the period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
ISSUED AT 703 PM EST THU NOV 25 2021
The cold front continues to move toward eastern KY, bringing very
low ceilings and reduced visibilities ahead of its passage.
Ceilings start off below 1K at most sites with a couple even
below 500 feet. Visibilities are generally MVFR/IFR but should
improve over the next few hours with the passage of the front. The
back edge of the main line of rain showers has entered the
western counties and will continue to drift southeast. Winds ahead
of the front are west/southwest at around 5 knots. Behind the
front winds will veer to the northwest. Some scattered rain
showers stick around with some snow flakes possible Friday morning
as northwest upslope flow continues and residual moisture lingers
over the area before tapering off by early afternoon. Ceilings
should rapidly improve Friday afternoon with some wind gusts of
around 15 knots are possible.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BATZ
SHORT TERM...GREIF
LONG TERM...HAS
AVIATION...BATZ
Area Forecast Discussion...UPDATED
National Weather Service Chicago/Romeoville, IL
858 PM CST Thu Nov 25 2021
.UPDATE...
Issued at 850 PM CST Thu Nov 25 2021
The going forecast for a chilly Thanksgiving night remains on
track. Just nudged down the forecast lows a couple degrees,
mainly in north central Illinois.
Stratocumulus continues to gradually be dragged southeastward in
the exiting cyclonic flow and be pulled gradually out of the
area. As of 900 PM, this back edge is along roughly the Fox River
Valley and should be out of Illinois by midnight. Much drier air
is helping to chew away at this as shown by the 0.08 inch PWAT on
the 00Z DVN sounding. While some high clouds do look to arrive
into northern Illinois near daybreak, much of the night ahead
looks clear after the stratocumulus departure. With dew points
dropping into the single digits over north central Illinois, lows
may overperform a bit. Going MET/MAV MOS guidance has lows of 7/8
in Rockford, respectively, and the HRRR has trended slightly
colder too. Do think some upper single digits are probable in at
least the cold spots of north central Illinois.
Otherwise, the lake effect snow or snizzle (snow/drizzle) into
Porter County, Indiana has continued to be very light.
Temperatures in this area are just now dropping to 32 and it is
likely the precipitation will end completely by 11 PM, so not
seeing any impacts materializing.
MTF
&&
.SHORT TERM...
Issued at 104 PM CST Thu Nov 25 2021
Through Friday night...
A potent upper wave is currently pushing overhead, and the combo
of mid-level frontogenesis and attendant upper jet divergence is
helping to squeeze out precipitation where this forcing has
intercepted deeper moisture. Rapidly-cooling mid-levels are
supporting a swift changeover to snow, but the spatiotemporal
overlap of better forcing for ascent and moisture will be brief.
In fact, drying within and above the dendritic growth zone is
already noted in visible satellite across northwest Illinois where
IR cloud top temperatures have warmed above -10 C with the loss
of the mid-level saturated layer. Thankfully, drying appears to be
occurring quickly enough to preclude the development of drizzle
in the sub-freezing airmass with saturated depths trending swiftly
to less than 2-3 kft.
Any precipitation of consequence peels east of the region through
the rest of the afternoon, but lake effect will linger in the
vicinity of Porter county in northwest Indiana into this evening.
Given the aforementioned rapid mid-level drying, lake effect
parameters remain pretty muted as ELs remain under about 7-8 kft
through this evening. Thermal profiles will maintain a rain/snow
mix through the rest of the afternoon, perhaps ending as all snow
early-mid evening before dry air shuts off precip production
entirely. While surface winds ease with time tonight, a lingering
breeze overnight will result in single digit wind chills across
most of the forecast area.
Surface ridge crests overhead tomorrow resulting in light surface
winds that will eventually become southwesterly through the
afternoon. Look for increasing mid-level cloud cover through the
day as our next disturbance--currently in Saskatchewan--drives an
enhanced wing of warm advection overhead. Some guidance suggests
top-down saturation may bring cloud bases down as low as 4-5 kft
late Friday evening/overnight and this would be low enough to
support some light (frozen) precipitation, but this is more of the
exception to the rule at this point among the multi-model suite at
this time and have left things dry through Friday night at this
time.
Carlaw
&&
.LONG TERM...
Issued at 107 PM CST Thu Nov 25 2021
Saturday through Thursday...
The pattern from the weekend onward will be dominated by upper-level
northwesterly flow atop a low-level baroclinic zone draped across
the Great Lakes. Usually, these patterns act like a highway for
clipper-like low pressure systems emanating from southern Canada
with bands of precipitation along and north of the path of each low.
Pinpointing the track of each clipper is often tricky at this range,
but an early glimpse seems to favor predominant track just north of
(but still pretty close to) our area. The best chance of
precipitation next week appears to be with a clipper poised to swing
through the Great Lakes Saturday afternoon with at least some signal
for a narrow band of showers in the vicinity of I-88 or I-80.
Forecast thermal profiles look pretty warm, favoring an all-rain
precipitation type with perhaps some window for snowflakes to mix in
just as precipitation is ending Saturday evening. In all, the system
does not currently appear to be a big trouble maker for our area.
Temperatures next week are expected to be fairly steady with highs
in the upper 30s to lower 40s, and lows in the upper 20s to lower
30s. With the upper-level jet stream directly overhead, broken to
overcast skies will prevail through next week. (In other words,
completely clear or sunny skies appear unlikely).
Borchardt
&&
.AVIATION...
For the 00Z TAFs...
533 PM...Forecast concerns include...
Gusty northwest winds this evening.
Mvfr cigs this evening.
The back edge of mvfr cigs currently extends from fep to vys and
is slowly moving east and is expected to shift east of ord/mdw by
03z this evening. A few flurries will be possible for the next
few hours as well. A period of skc is expected overnight with
increasing mid clouds Friday afternoon into Friday evening.
Northwest winds will remain gusty this evening, into the lower/mid
20kt range. The gusts are expected to slowly diminish through the
late evening with gusts ending after midnight, but only medium
confidence on these trends with gusts possibly ending earlier then
expected. Winds should remain northwest or west/northwest into
mid/late Friday morning, then turn west, southwest and eventually
southerly by Friday evening, with speeds under 10kts. cms
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory...IL nearshore waters until 3 AM Friday.
Small Craft Advisory...LMZ743-LMZ744 until 9 AM Friday.
Small Craft Advisory...Burns Harbor to Michigan City IN until 3
PM Friday.
&&
$$
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Area Forecast Discussion
National Weather Service Norman OK
501 PM CST Thu Nov 25 2021
...New AVIATION...
.SHORT TERM...
(This evening through Friday)
Issued at 118 PM CST Thu Nov 25 2021
Latest RAP model continues to weaken the pressure gradient at the
surface, as well as winds up through the boundary layer. Surface
observations are also confirming the RAP model trends. As a result,
will expect our windspeeds and gusts out of the north to continue
decreasing through the afternoon. After sundown, high surface
pressure will start building as our cold upper trough axis makes its
way through. As winds go light and variable after sundown under
clear night skies and within a cooler air mass, will expect strong
radiational cooling to begin. Expecting most of our areas
temperatures to eventually drop below freezing, although not
expecting much of a wind chill as winds should stay near calm. Did
go slightly cooler with the MinT using the NBM 25th percentile. As
southwest winds begin to increase after sunrise Friday, will expect
a warming trend to begin as temperatures rebound back to more
seasonably by the afternoon across much of our area. Our western
CWA could even become a little bit warmer being more downwind of the
Texas Panhandle. As a result, went slighlty warmer than NBM using
the CONSMOS for Fridays MaxT.
&&
.LONG TERM...
(Friday night through next Wednesday)
Issued at 200 PM CST Thu Nov 25 2021
Models show generally NW flow aloft through the middle of next
week with a generally dry forecast through that time. There is one
exception this weekend. Models continue to show a closed low that
eventually opens up into a wave moving across Mexico into the
southern Plains this weekend. Meanwhile, a shortwave also moves
across the northern Plains into the Midwest which will drag a cold
front across the fa. This front along with the closed low could
bring a chance for precipitation to southern parts of the fa
Saturday.
Overall, above normal temperatures are expected this weekend into
late next week with a general warming trend continuing through
Monday, except for a hiccup in the trend Sunday due to some cooler
air behind the previously mentioned cold front. However, the
temperatures on Sunday will still be near/above average just a bit
cooler than Saturday.
&&
.AVIATION...
(00Z TAFS)
Issued at 441 PM CST Thu Nov 25 2021
Winds are starting to wind down for the night. Wind direction will
shift from northerly to southerly overnight. Skies will remain
clear.
Day
&&
.UPPER AIR...
Issued at 118 PM CST Thu Nov 25 2021
No Upper Air Flights are planned.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 28 62 40 65 / 0 0 0 10
Hobart OK 26 63 40 66 / 0 0 0 10
Wichita Falls TX 28 65 41 64 / 0 0 0 30
Gage OK 27 70 35 65 / 0 0 0 0
Ponca City OK 25 64 35 65 / 0 0 0 0
Durant OK 27 61 37 63 / 0 0 0 30
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
SHORT TERM...68
LONG TERM....25
AVIATION...14