Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/19/25
Area Forecast Discussion
National Weather Service Cheyenne WY
621 PM MST Tue Feb 18 2025
.KEY MESSAGES...
- Bitterly cold temperatures will remain entrenched over the
High Plains through Thursday, and will briefly reach as far
southwest as Laramie and Rawlins tonight.
- Bands of moderate to locally heavy snowfall are expected this
afternoon and evening, mainly along the I-80 corridor.
- Moderate to heavy mountain snowfall will continue into early
Wednesday, with another weaker system possible Thursday into
Friday. Total accumulations from this extended stormy period
will be on the order of several feet.
- Warmer, drier, and windier weather will return for the weekend
into early next week.
&&
.UPDATE...
Issued at 615 PM MST Tue Feb 18 2025
Latest radar loop continues to show bands of frontogenesis
taking place across Albany and Laramie counties. These bands
have been producing snowfall rates around a half inch an hour
with snowfall amounts already at 4 inches at the NWS in
Cheyenne. These bands of snow will continue to affect this area
during the next several hours before diminishing overnight. As
a result, we went ahead and upgraded our Winter Weather
Advisories and Warnings for these counties. Would not be
surprised to see amounts ranging from 4 to 8 inches before
ending tomorrow morning.
&&
.SHORT TERM /THROUGH THURSDAY/...
Issued at 139 PM MST Tue Feb 18 2025
The chill continues across the eastern half of the CWA today as the
arctic front continues to be pushed against the Laramie Range.
Current temperatures east of the Laramie Range are below zero to the
single digits and are expected to stay that way throughout the day.
Areas to the west get to experience balmy temperatures in the 30s
this afternoon, as some sunshine peaks through clouds. A secondary
shortwave dropping in from the north this afternoon will bring
another round of snow to the area. Light snow is currently ongoing
for most areas under the arctic front, however, snow will push into
areas west of the Laramie this afternoon and become more widespread.
The set-up for this system lends itself to being an efficient snow
producer. With the arctic front hung up on the Laramie Range, a
strong band of frontogenesis will rapidly develop late this
afternoon and through the evening hours. This band will stretch
roughly along a line from Muddy Gap to Cheyenne, with the strongest
frontogenesis likely between Cheyenne and Laramie. Co-located with
this band are mid-level negative EPV values, suggesting the
potential for heavy banded snow within the vicinity of the strong
frontogenesis. On top of this, model soundings show a warm nose
aloft. Warm air overrunning cold air at the surface tends to also
lead to efficient snowfall generation across the forecast area.
This warm nose is also where the saturated DGZ is located,
adding to the fact that snowfall rates could be rather
impressive at times. Given all these variables, heavy banded
snow with good snowfall rates is likely somewhere along the
Interstate 80 corridor in Wyoming this evening. Hi-Res guidance
like the HRRR has potentially narrowed down this area to be
somewhere between Arlington and Pine Bluffs. Regardless of
where this band sets up, it is likely that somewhere underneath
this band will see 6+ inches of snow. Winter Weather Advisories
are in place along most of the Interstate 80 corridor to cover
the potential for moderate amounts of accumulating snow. Even if
a band does not set up over Laramie or Cheyenne, these are
still areas to watch for snow accumulation up to 6 inches as
both cities will likely experience upslope flow at some point
during this snow event. Hi-Res guidance shows snow tapering off
late tonight.
The arctic temperatures continue overnight and into the day
tomorrow. This secondary shortwave will send a reinforcing shot of
cold air into the CWA this evening. 700 mb temperatures will be in
the 10th percentile of NAEFS climatology tonight and through the day
Wednesday. Low temperatures east of the Laramie Range will be below
zero, with the coldest temperatures expected in the Nebraska
panhandle. Wind chills will range from -15F to -25F overnight.
Extreme Cold Warnings are still in place for the panhandle through
Thursday morning. With the arctic front still in place on Wednesday,
lingering snow showers, clouds, and of course cold, are expected.
High temperatures in the panhandle will still only be in the
single digits. However, evidence of the front retreating will be
seen along the Interstate 25 corridor with highs returning to
the teens. Once again, overnight lows on Wednesday will be well
below zero for western Nebraska with wind chills below -20F.
However, this should be the last of the bitter cold for the week
as arctic front retreats eastward on Thursday.
Warmer temperatures are forecast for Thursday, however, the far
eastern Nebraska panhandle will still be on the fringes of the
arctic front as it pushes eastward. Temperatures will still be below
average, but a far cry from the single digits and negatives from the
previous few days. Yet another shortwave will push into Wyoming
during the day Thursday. This system lacks some mid-level moisture,
however, orographic lift will likely lead to mountain snow
developing in the Snowy and Sierra Madre Ranges. Some snow could
creep into the lower elevations, but the lack of moisture will lead
to little to no accumulations.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Issued at 445 AM MST Tue Feb 18 2025
Medium and extended models in good agreement, at least through
next weekend, and continue to show a gradual warming trend with
the possibility of some early spring-like weather Sunday and
next Monday. Before this, however, we will have to get through
one more chilly day on Thursday with another potential for
additional snowfall.
All models show the arctic airmass gradually eroding and
retreating eastward on Thursday as 850mb temperatures increase
above -10c through the day. Expect this to be a slow process,
mainly due to weak westerly winds just off the surface west of
the Laramie Range...suggesting weak to modest WAA aloft. At the
surface, winds are forecast to remain out of the south or even
southeast across the eastern plains and for most locations along
and east of the Interstate 25 corridor. Expect some of the
arctic air to linger across the eastern plains into Thursday
afternoon, especially in areas with a decent snow pack. Decided
to trend high temperatures below guidance, especially for the
south facing ridges, such as the Cheyenne and Pine Ridge where
high temperatures may struggle to get out of the teens for much
of the day. Another slow moving upper level trough will dig
southeast into the four corners region Thursday and Thursday
night. There should be just enough forcing and WAA aloft to
justify a few bands of light snow developing and shifting
southeast through the day across mainly southeast Wyoming. The
bulk of the dynamic forcing associated with this system should
remain west and south of the forecast area, so not expecting any
impacts at time due to the short duration of the event. Low
temperatures Thursday night and Friday will remain very cold,
but should start to moderate after midnight across southeast
Wyoming as westerly winds increase slightly.
For Friday and next weekend, all models in agreement and show a
broad ridge gradually shifting eastward into the Rocky Mountain
Region, with the ridge axis flattening by late Sunday. 700mb
temperatures forecast to increase to 0c to 5c late this weekend.
Might still be dealing with some residual snowpack in spots, so
kept temperatures a few degrees lower than guidance for Friday
and Saturday and then gradually increased high temperatures
towards the NBM and GEPS/ENS 50th to 75th percentile ensemble
blend. This puts most of the high plains well into the 50s and
near 60 Sunday afternoon which seems reasonable. The only concern
in the extended, including late this weekend and early next
week, will be increasing westerly winds and the potential for
strong winds in the wind prone areas of southeast Wyoming...and
possibly strong in the sub-wind prone areas as 700mb winds
increase over 50kts with good near-surface pressure gradients.
Increased winds above High Wind criteria with good support from
in-house wind models, but will continue to monitor this week.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 440 PM MST Tue Feb 18 2025
MVFR to LIFR conditions continue through the first half of the
TAF period as bands of snowfall bringing low VIS and lowered
CIGs continue to move through the region. Once this activity
moves out later this evening, into the overnight hours, we
should see CIGs and VIS gradually lifting, though lingering BR
could continue to inhibit some visibilities, and CIGs for
CYS/LAR are expected to remain MVFR status through the period.
Strong gusts of 25-35 knots expected for LAR and RWL through the
next few hours but should begin weakening, but another push of
strong winds is then expected for RWL tomorrow afternoon.
Otherwise all other sites expecting average winds to be 10 knots
or less with occasional gusts with bands of snowfall possible.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Winter Weather Advisory until 11 PM MST this evening for
WYZ107-108.
Winter Weather Advisory until 5 AM MST Wednesday for WYZ106-
115-119.
Cold Weather Advisory until 11 AM MST Wednesday for WYZ102-108-
119.
Winter Storm Warning until 5 AM MST Wednesday for WYZ110-
116>118.
Winter Weather Advisory until 11 AM MST Wednesday for WYZ112.
Winter Storm Warning until 11 AM MST Wednesday for WYZ114.
NE...Extreme Cold Warning until 11 AM MST Thursday for NEZ002-003-
019>021-054-055-095-096.
Winter Weather Advisory until 11 PM MST this evening for
NEZ019>021.
Winter Weather Advisory until 5 AM MST Wednesday for NEZ054-
055.
&&
$$
UPDATE...REC
SHORT TERM...SF
LONG TERM...TJT
AVIATION...CG
Forecast Discussion at weather.gov/mqt.
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Cold Weather Advisory from midnight tonight to 9 AM CST
Wednesday for MNZ010-011-018-019-026-035-037.
Extreme Cold Warning from midnight tonight to 9 AM CST
Wednesday for MNZ025-033-034-036-038.
WI...Cold Weather Advisory from midnight tonight to 9 AM CST
Wednesday for WIZ002>004-008-009.
Extreme Cold Warning from midnight tonight to 9 AM CST
Wednesday for WIZ001-006-007.
MARINE...Small Craft Advisory until 10 AM CST Wednesday for LSZ140>142.
&&
$$
DISCUSSION...Huyck
AVIATION...Britt
MARINE...Huyck
Area Forecast Discussion
National Weather Service Goodland KS
722 PM MST Tue Feb 18 2025
.KEY MESSAGES...
- An Extreme Cold Warning remains in effect for the entire Tri-
State area through mid day Thursday, when a prolonged period
of dangerously cold weather will affect the region.
- Much warmer temperatures return Saturday through Monday with
the warmest day being Monday when high temperatures will be in
the 60s.
&&
.UPDATE...
Issued at 722 PM MST Tue Feb 18 2025
With radar coverage decreasing over the Tri State region, have
opted to cancel the Winter Wx Advisory early for the entire
area. Still some light echoes showing up over the CWA, and
another batch near the CO/WY border. This has been slowly
eroding away in the past couple hours, but can`t rule out an
additional isolated dusting to an inch of additional snow over
the next several hours. This does show up in the latest CAMs
(HRRR, RAP and NamNest). The Extreme Cold Warning remains in
effect.
&&
.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 235 PM MST Tue Feb 18 2025
No significant changes to the prior forecast. No significant
change to forecast expectations, in general.
Extreme Cold Warning...remains in effect tonight through mid-
day Thursday for the entire Tri-State area. Wind chill readings
ranging from -20 to -30F are expected through Wednesday morning
and again Wednesday evening into Thursday morning. Throughout
the entire warning period, wind chill readings warmer than -10F
will be far and few between (mainly a few hours Wednesday
afternoon).
Winter Weather Advisory...remains in effect through midnight
tonight. Simulated reflectivity, liquid precipitation and snow
accumulation products via current and recent runs of high-
resolution guidance (HRRR, RAP, NAM NEST) continue to suggest
that a narrow band of snow will develop in northern CO around
sunset (~00Z).. progressing ESE into portions of northwest KS
and southwest NE this evening/tonight, with the majority of
additional accumulating snow (1-2") occurring in the ~02-10Z
time frame. Locally higher amounts (up to 3") cannot be ruled
out.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
Issued at 115 PM MST Tue Feb 18 2025
One more cold morning in store on Friday with lows in the
single digits above/below zero and wind chills 10 to 15 below.
Shortwave trough will be moving through Friday afternoon with
possibly a light dusting of a half inch or less, but models are
trending drier and NBM pops have dropped to 10 percent or less.
Temperatures will begin to moderate with highs Friday afternoon
in the 20s and 30s and lows Friday night in the single digits
and teens. Northwest flow continues on Saturday with another
fast moving shortwave trough moving through. Models have little
to no precipitation with it so will keep the forecast dry.
Temperatures continue to climb with highs on Saturday in the 40s
and 50s and lows Saturday night in the 20s.
For the Sunday through Tuesday period, northwest flow continues
around a ridge centered over the southwest CONUS. Surface winds
will have a westerly component which will further aid in
warming. There is a cold front forecast on Tuesday which may be
accompanied by a period of breezy northwest winds but has little
impact on temperatures. High temperatures during the period
will generally be in the 60s and 70s and lows in the 20s and 30s
with no precipitation expected.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 420 PM MST Tue Feb 18 2025
For KGLD, mainly MVFR conditions through 18z Wednesday.
Ceilings will range from OVC010-025. 5-6sm in light snow
through 10z. IFR conditions may ensue from 03z-07z w/ 1-2sm
possible. From 18z onward, VFR. Winds, east around 10kts
through 07z, then becoming northerly. By 15z, light/variable.
For KMCK, VFR/MVFR/IFR mix with light snow through 19z
Wednesday dropping visibility to 2-6sm. Ceilings OVC020-035.
VFR from 19z onward. Winds, northeast around 10kts through 09z,
then light/variable.
&&
.CLIMATE...
Issued at 315 AM MST Tue Feb 18 2025
RECORD DAILY LOWS
_______________________________________________________
Feb 18 Feb 19 Feb 20 Feb 21
_______________________________________________________
Goodland -4 (2006) -4 (1908) -1 (1953) -5 (1953)
McCook -10 (1936) -9 (1929) -8 (1918) -7 (1911)
Hill City -10 (1936) -2 (1929) -4 (1918) -8 (1978)
Burlington -11 (1942) -6 (2006) -8 (2018) -8 (2018)
RECORD DAILY LOW MAXIMUMS
_______________________________________________________
Feb 18 Feb 19 Feb 20 Feb 21
_______________________________________________________
Goodland 15 (2006) 9 (1955) 16 (1918) 19 (1971)
McCook 10 (2006) 16 (1955) 9 (1918) 20 (2013)
Hill City 13 (2006) 13 (1955) 14 (1918) 18 (1968)
Burlington 8 (2006) 9 (2006) 16 (2018) 16 (1913)
____________________________________
RECORD MONTHLY LOWS FOR FEBRUARY
____________________________________
Goodland -24 (2/15/2021)
McCook -26 (2/8/1933)
Hill City -23 (2/8/1933)
Burlington -24 (2/15/2021)
____________________________________
ALL-TIME RECORD LOWS
____________________________________
Goodland -27 (12/22/1989)
McCook -30 (1/12/1912)
Hill City -26 (12/22/1989)
Burlington -25 (1/4/1959)
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Extreme Cold Warning until 11 AM MST /noon CST/ Thursday for
KSZ001>004-013>016-027>029-041-042.
CO...Extreme Cold Warning until 11 AM MST Thursday for COZ090>092.
NE...Extreme Cold Warning until 11 AM MST /noon CST/ Thursday for
NEZ079>081.
&&
$$
UPDATE...JN
SHORT TERM...Vincent
LONG TERM...024
AVIATION...JN
CLIMATE...99
Area Forecast Discussion
National Weather Service Green Bay WI
838 PM CST Tue Feb 18 2025
New Information added to update section
.UPDATE...
Issued at 837 PM CST Tue Feb 18 2025
Clouds have quickly shifted south into northern Wisconsin. Northerly
flow should push the clouds over much of north-central and far
northeast Wisconsin. Indications are the clouds will then diminish
late tonight as they shift farther south. The clouds have kept
temps warmer over far north-central and northeast WI this evening
so far, but temps are starting to drop elsewhere, with lowest
readings as of 830 pm around -5F. Though the clouds may effect
temp trends into the early overnight for parts of northeast WI,
does appear that expected min temps may still occur. Thus, no
plans to alter the going Cold Weather Advisory as the areas that
were already not in it will be impacted the most by the cloud
cover. Will have updated Cold Weather Advisory statement out by
930 pm.
&&
.KEY MESSAGES...
- Wind chill readings of 15 to 25 below zero are forecast late tonight.
A Cold Weather Advisory has been issued for central and east-
central Wisconsin. These wind chills can cause frostbite in as
little as 20 to 30 minutes.
- A warming trend will take place later this week. High
temperatures will return to the 20s by Thursday and into the 30s
by Sunday.
&&
.DISCUSSION...
Issued at 122 PM CST Tue Feb 18 2025
Short Term...Tonight and Wednesday
The latest RAP analysis and satellite/radar imagery show 1047mb
arctic high pressure stretching from Alberta to the southern Great
Lakes early this afternoon. With the exception of far northern
Wisconsin due to lake effect, most of the state has enjoyed clear
conditions so far today. Looking upstream, clouds are streaming
in from South Dakota to southern Minnesota while clouds are also
increasing across Lake Superior where warm advection is most
unusually occurring from the northeast. Forecast concerns mainly
revolve around wind chills tonight followed by light snow chances
on Wednesday.
Wind Chills Tonight: Strong arctic high pressure will very slowly
shift south into the northwest Great Plains, thereby maintaining a
modestly tight pressure gradient across the western Great Lakes.
After some gustiness this afternoon, winds will diminish tonight,
but the pressure gradient looks to be sufficient to have winds
decouple at times, particularly across the northwoods. Clouds will
also be increasing from the northeast with help from lake effect
into north-central WI where wind trajectories will remain north-
northwest. Extent of cloud cover and winds make it difficult to
determine the potential for wind chill headlines.
Low temperatures have increased across far northeast WI due to
cloud cover. However, given the airmass and deep snow pack,
trended temps colder than the NationalBlend, and not far from the
NBM 50th percentile. Combined with some moderation of the arctic
airmass, do not foresee as cold a night tonight with lows ranging
from 5 below to 15 below for most. Combined with a slight 5-10 mph
breeze, wind chills will be approaching 20-25 below over central
and east-central WI late tonight into Wednesday morning.
Decided to issue a Cold Weather Advisory for central to east-
central Wisconsin as wind chills will be right around criteria
from about midnight to 9 am.
Snow Chances Wednesday: Broad, upper level low pressure will move
into the western Great Lakes. Warm advection will continue to
occur from the north, but deepest moisture should generally reside
over the Upper Peninsula and northern Illinois. Therefore, the
highest chances for light snow will occur over northern WI where
lake effect will help augment the warm advection. It`s possible
that a few flurries could make into central and east-central WI by
late in the afternoon. Up to a half inch of accumulations is
possible across the north. Warmer high temperatures ranging
through the teens.
Long Term...Wednesday Night Through Tuesday
Low impact forecast persists for the majority of the extended, in
stark contrast to what we`ve seen over the past week. Main
concerns will be front-loaded through the end of the work week as
early morning wind chills remain in the single digits below zero.
Otherwise, snow chances remain minimal given a general lack of
organized synoptic systems.
Snow chances... Periods of light lake effect snow look to be
possible over the far north early on Thursday as winds veer to
north/northwesterly along the leading edge of surface high
pressure over the northern Plains. Lake surface to 850 mb delta Ts
range from around 15 to 18C during this time, with probabilistic
guidance showing around a 50 to 70 percent chance of exceeding one
inch of snowfall in northern Vilas. Suspect that northerly wind
component should keep any snow offshore along/east of the Fox
Valley.
Next chances for more widespread snow arrive late this weekend
as a warm front ushers in a push of WAA with reinforcement from
isentropic ascent. However, snowfall amounts look to be held down
to less than an inch as the profile struggles to saturate, with
moisture topping out at around 700 mb. Probabilities for receiving
one inch of snow range from around 10 to 30 percent area-wide.
Temperatures... Following a prolonged period of abnormal cold,
long-range guidance picks up on a signal for a pattern shift to
above average temperatures through the end of the month. Return
flow settles in across the upper Midwest this weekend as high
pressure departs to the east, resulting in temperatures rebounding
into the upper 30s. Some areas across central and east-central
Wisconsin may even see 40 degrees Monday and Tuesday. This being
said, current thinking is that temperatures may underperform
slightly due to existing snow pack, although should have a better
idea in the coming days.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 548 PM CST Tue Feb 18 2025
Expect clear skies across most of the region except near the U.P.
border. MVFR clouds will then slowly edge south overnight across
far northern WI with scattered light snow showers north of a RHI
to IMT line.
Clouds are expected to become more widespread by late morning
Wednesday, with MVFR ceilings expected in most places. Light snow
showers are possible in the afternoon north of a RRL to SUE line.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Cold Weather Advisory from midnight tonight to 9 AM CST
Wednesday for WIZ018>020-030-031-035>040-045-048>050.
&&
$$
UPDATE.........JLA
DISCUSSION.....MPC/Goodin
AVIATION.......JLA
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
957 PM EST Tue Feb 18 2025
.SYNOPSIS...
Wintry weather is likely for parts of the area on Wednesday as a
fast-moving low pressure system passes across the Southeast. Dry
high pressure returns Thursday bringing very cold weather to end the
week. A dry pattern with a warming trend is expected to begin over
the weekend, with above-normal temperatures expected to return early
next week.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
As of 955 PM Tuesday: Benign conditions will continue through much
of the overnight period as high clouds continue to stream overhead.
Precipitation will gradually push east across Tennessee and towards
the mountains by daybreak with light snow expected across much of
the mountains by 7am. The forecast is in good shape and reflects
these expectations well with only minor adjustments needed with
this update.
Otherwise, arctic airmass extends from the northern Plains across
the Ohio Valley to the Chesapeake Bay region, evidenced by dewpoints
at or below zero across the latter area. We`ve mixed down some of
that dry air, resulting in dewpoints having fallen into the upper
teens in portions of our CWA. They will rebound a bit with the loss
of diurnal mixing, but will remain low tonight. Cirrus/altostratus
cloud cover will fill in across the area overnight which will limit
radiational cooling. Meanwhile, as upper trough swings across the
southern Plains and MS Valley, Miller-A sfc cyclone will develop
and track south of the CWA over the course of Wednesday. No
general change in this thinking. Warm upglide over the dry high,
coupled with divergence in RR quad of amplifying 250mb jet, will
lead to the development of light precip across the area during the
morning. Some flavor of diabatically enhanced CAD may technically
develop, although the closed upper low approaching the area by the
end of the period (00z Thu) suggests it will erode fairly quickly.
12z guidance generally agreed pretty well with the previous forecast
in terms of timing; QPF went a little upward on some guidance and
down on others. CAMs suggest the very dry airmass/wedge will be
a bigger factor in limiting precip amounts in our east than some
models had previously suggested; a "hole" can be seen in modeled
reflectivity progs. Through the passage of the cyclone, many areas
in our east are not expected even to see 0.10" liquid QPF. With
more models depicting minimal QPF, PoPs have fallen a bit further
in many areas, but likely range values are still forecast in all
zones at some point during the day.
Although most guidance has also trended slightly warmer, evaporative
cooling still could be a big factor in precip type especially
at onset. Overnight temps look to remain above freezing in most
of our SC/GA zones except for the higher elevation areas. It
is possible some areas may see temps dip slightly colder in
late morning after the period that represents our forecast "low
temp." Where wet-bulbs are near or below freezing, precip likely
will begin as snow. A transition zone still is likely to develop
as a weak warm nose develops via the upglide, late morning to
mid-afternoon. Sleet would be likely to mix in where that develops,
but freezing rain could also result where sfc temps are below
freezing. The 12km NAM took a sharp turn colder after the onset
of precip, which combined with its somewhat stronger warm nose
leads it to generate appreciably more FZRA than other guidance,
even the 3km NAM. A sleet mention was retained in our southeast
corner (near CLT) but with temps hovering just above freezing in
that area through the bulk of precip no FZRA is mentioned. Precip
will become less likely by afternoon over the mountains (except
near the TN border). Ice nuclei may be less available as drying
occurs from the top down, from west to east in the afternoon. Areas
that are below freezing could see some freezing drizzle develop,
but confidence is low on that occurrence. Snow amounts in the
northern portions of the northern tier of GA/SC zones are expected
to be less than a half inch, and there appears no need to extend
the Winter Wx Advisory there. Amounts of snow/sleet are slightly
more in York/Chester counties, but the expectation of temperatures
remaining above freezing suggests minimal travel impacts thru 00z
Thu, so they too are being omitted. A change to FZRA is possible
in those counties Wed night, but that chance appears too low for
an Advisory on its own.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
As of 145 pm Tuesday: Cyclone will pull away from the Carolina Coast
by Thursday morning, with center of an upper low forecast to barrel
across the Ohio Valley and Mid-Atlantic Wed night/Thu. Low level
flow will briefly back across our area in response to this latter
feature...maintaining weak low-level lift and ample moisture Wed
night. This could result in some light snow showers/flurries along
with pockets of drizzle or freezing drizzle during the evening, as
temps dip into the 20s across much of the area by Thu morning.
Forcing will deepen after midnight, as the upper low begins to pass
north of the area...with the exit region of associated strong upper
jet max expected to move over the area between 06-12Z Thu. This is
forecast to enhance the potential for accumulating northwest flow
snow showers across the mountains...while perhaps supporting a
quick-moving batch of snow showers (20-30 PoPs) developing over
portions of the Piedmont between daybreak and late morning. This
latter area could bring additional snowfall of up to an inch to
portions of the Piedmont. However, confidence in this scenario is
low at this point. Otherwise, the main impact is expected to be
additional accumulations of 1-3 inches across portions of the
counties bordering TN/NC during the first half of the short term.
Northwest flow snow showers will taper off to flurries by Thu
evening, with dry conditions expected through the remainder of the
period. Temperatures Thu/Thu night will be quite cold...around 20
degrees below normal. Gusty winds developing in the cold advection
flow...with gusts in the 30-40 mph range expected across much of the
mountains...will yield wind chill values in the single digits or
lower across much of the mountains. However, it appears for now that
values reaching Cold Wx Advisory criteria will primarily be confined
to elevations above ~4000 feet. Low wind chill values will continue
into Fri morning, but a decent warm-up is anticipated (maxes 10-12
degrees below normal) during the afternoon, as heights rise with
upper trough pulling away from the East Coast.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 200 pm Tuesday: A dry pattern will be established across the
region during the extended...with a fast W/NW flow aloft expected to
encompass much of the country. Multiple dampening short wave troughs
are expected to sweep across the region at various times throughout
the period. These could bring very brief periods of northwest flow
light snow or rain showers to the mountains...especially later in
the period, but any impacts should be minimal. Otherwise, the
airmass is expected to remain too dry to support precip development.
A warming trend that will begin Friday is expected to continue
through much of the period, with temperatures forecast to warm to
near-normal levels by Sunday...and perhaps to as much as 10 degrees
above climo by the end of the period.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: The TAF period starts off VFR this evening as
mainly high clouds stream across the area. Conditions head downhill
overnight into Wednesday morning as wintry precipitation moves into
the area along with lowering ceilings and reduced visibility.
Temperatures will be cold enough north of I-85 (KAVL, KHKY, KCLT) to
support all snow as the precipitation type with the potential for
some sleet to mix in as well. Farther south, at KGSP and KGMU, a mix
of rain and snow is expected with just cold rain at KAND. Snow will
be light, but moderate snow rates and further reductions in
visibility cannot be ruled out depending on where any snow bands
materialize. A lull in wintry precipitation may occur during the
evening hours before a second round of light snow blossoms overnight
Wednesday into early Thursday morning. IFR visibility will be common
with any snow. Otherwise, ceilings will lower through the morning
with widespread IFR common by the mid morning hours. LIFR ceilings
may eventually develop towards the end of the period as well. Winds
will shift to out of the northeast this evening and will remain
through the period.
Outlook: Wet surfaces may freeze as temperatures fall below
freezing Wed night and deicing could be necessary Thu morning. Dry
high pressure returns late Thursday and lingers into the weekend.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...Winter Weather Advisory from 6 AM Wednesday to noon EST
Thursday for GAZ010.
NC...Winter Weather Advisory from 6 AM Wednesday to noon EST
Thursday for NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510.
SC...None.
&&
$$
SYNOPSIS...JDL
NEAR TERM...TW/Wimberley
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...TW
Area Forecast Discussion
National Weather Service Gray ME
1048 PM EST Tue Feb 18 2025
.SYNOPSIS...
Cold high pressure builds in early this week with gusty winds
diminishing this evening and tonight. Low pressure likely
passes well south of New England on Thursday. High pressure
then continues to gradually build in during the weekend with a
moderating trend.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
1045 PM Update... Gusty westerly winds are continuing at this
hour with some gusts still at around 35 mph. This combined with
the cold air temperatures into the single digits and teens is
sending wind chills to near or below zero in most locations.
Made some adjustments to overnight temperatures and winds but
the overall forecast remains on track.
Went ahead and converted the remaining gale
warning to a small craft advisory based on latest trends in wind
gusts. A few gusts up to around 35 kt will remain possible for
the next hour or two but most will be weaker.
Previously...
Updated temperatures, winds and surface dew points for the near
term portion of the forecast. Dry conditions will continue
outside of a few upslope snow showers in the mountains
Temperatures will be falling below zero in the north this
evening.
Prev Disc...
Breezy but otherwise quiet weather continues into
early this evening. Forecast soundings support gusts of 30 to 40
mph for a few more hours, but then winds will then steadily
ease through tonight (although still 20-25 mph at times). Latest
RAP analysis indicates a 500mb shortwave draped across the
International Border, and this will gradually work its way
southward through this evening into the early part of tonight.
It will be running into quite a bit of dry air, so for areas
south of the mountains, mainly just an increase in cloud cover
with perhaps some flurries here and there. In the mountains,
there will be a continued chance of snow showers tonight with
upslope flow remaining.
It will be another cold night with enough of a breezy to bring wind
chills as low as -10F south of the mountains and -15F to -20F in the
mountains (except much lower going up in elevation).
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Model guidance is depicting a weak upper low forming across southern
Quebec on Wednesday, resulting in a few snow showers for far
northern areas (with upslope flow still in place too).
Otherwise dry conditions are expected across the remainder of
the area as low pressure currently over the Canadian Maritimes
pulls farther away. This will allow the pressure gradient to
relax and result in less breezy conditions across the area, but
we still may see gusts 25-30 mph in the morning before a
downward trend going into the afternoon. Comparatively, it will
probably feel pretty nice out compared to today and Monday with
the lighter winds and temperatures mostly in the 20s, except
some teens in the mountains.
Low pressure emerges off the coast of the Carolinas Wednesday night
while shortwave ridging overhead maintains dry conditions over New
England. Winds will be light enough for good radiational cooling,
but there may be some mid/high clouds from the low pressure well to
the south that end up leveling off cooling at some point overnight.
I have blended in some cooler guidance to bring temps down a bit but
haven`t gone too low due to the potential increasing clouds.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
04Z Long Term Forecast Update... Little change in the latest NBM
guidance for the extended portion of the forecast. Low pressure
passing well southeast of the area may result in a few flurries
over the southern coast on Thursday. After this mainly dry
weather and moderating temperatures look likely with our next
chance for precipitation possibly arriving early next week.
Previously...
Key Messages:
* Coastal low brushes the area to the south and east Thursday
evening with some potential flurries/snow showers along the coast.
Gusty northwest winds are expected in the wake of this system
Friday.
* Quiet period of weather beyond this through early next week with
temperatures moving to around...or just above normal.
--Pattern and Summary--
There is a pattern shift occurring over the northern hemisphere this
week as downstream blocking over Greenland relents and the NAO
pushes into positive territory by week`s end. In the Pacific...a
similar...though less dramatic shift in the EPO from negative to
positive will allow for an increasing Pacific influence across North
America. Ensembles are in good agreement on an extended stretch of
quiet weather through the long the forecast period with the
increasing Pacific influence bringing slowly moderating
temperatures.
--Details--
Thursday: EC-EPS/GEFS in strong agreement that trough digging into
the northeastern US will spawn low pressure which will remain well
south and east of the benchmark late Thursday and Thursday night.
Despite this track...some of the guidance suite has some light snow
brushing coastal areas. Otherwise...mostly cloudy and seasonably
cool conditions with northerly winds strengthening Thursday night.
Friday through Sunday: High pressure ridge axis builds into the
region for Friday and Saturday before a northwesterly flow regime
becomes entrenched aloft. Well-placed DGZ and NNW upslope supports
mountain SHSN Thursday night into Friday with otherwise dry
conditions with quiet weather to the south and east. T9s around -10C
Friday and Saturday begin to moderate to around -7C Sunday as the
flow begins to back ahead of next approaching northern stream wave.
This will yield highs in the 20s on Friday moderating to the upper
20s-mid 30s from north to south by Sunday.
Monday and Tuesday: Fast-moving, shortwave-laden northwesterly flow
opens the new work week with mountain snow showers...some of which
may push into the foothills and coastal plain. Temperatures should
end the period close to seasonal norms...with most spots in the 30s.
&&
.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
Short Term...Mainly VFR through Wednesday night, except for the
possibility of MVFR ceilings/snow showers at HIE. Even though
west to northwest winds will remain somewhat breezy into this
evening, a steady downward trend is expected through tonight.
Winds will be less breezy Wednesday but could reach 20-25 kt at
times, mostly in the morning.
Long Term...VFR conditions are expected to dominate the long
term forecast period. Low pressure passing well south and east
of the region Thursday night may spread a few flurries/light
SHSN to the coastal terminals. Gusty northwest winds /15G25kts/
are expected Friday before quieter conditions through the
weekend.
&&
.MARINE...
Short Term...Gales persist through this evening but will switch
to SCA conditions overnight through early Wednesday morning as
winds gradually subside. Conditions then likely remain below
SCA levels through Wednesday night.
Long Term...Low pressure will pass south and east of the waters
Thursday night with gusty northwest winds developing as it
departs Friday. SCAs will be necessary and depending on the
proximity of the low...gale force wind gusts will be possible
over the outer waters. Northwest winds will subside as a high
pressure ridge axis builds into the region this weekend.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 10 AM EST Wednesday for ANZ150-152-
154.
Freezing Spray Advisory until 9 AM EST Wednesday for
ANZ150>152-154.
Small Craft Advisory until 4 AM EST Wednesday for ANZ151.
&&
$$
NEAR TERM...Tubbs
SHORT TERM...Combs
LONG TERM...Arnott
Area Forecast Discussion
National Weather Service Morristown TN
822 PM EST Tue Feb 18 2025
...New UPDATE...
.UPDATE...
Issued at 806 PM EST Tue Feb 18 2025
No changes were made to the forecast for tonight during the
evening update. Timing for snow arrival looks to be on track. Snow
is being reported in Clarksville and Hopkinsville. Nashville area
is not reporting snow yet but reflectivity shows that snow is on
their doorstep. Snow will begin after midnight for the Cumberland
Plateau counties, in the early morning hours for the Tennessee
Valley and closer to sunrise farther east. Light accumulation will
be possible before sunrise especially in the Upper Cumberland
Plateau.
&&
.SHORT TERM...
(This evening through Thursday)
Issued at 300 PM EST Tue Feb 18 2025
1. Snow expected to begin late tonight/early Wednesday morning for
most of the area, transitioning into scattered snow showers
Wednesday night.
2. Cold temperatures may cause travel impacts through Thursday
night.
Currently the low pressure system to our south is continuing to
develop and track along the Gulf Coast today, and will continue
along it`s trajectory heading into tomorrow. This will combine with
an upper level jet further to our north across parts of the
Tennessee and Ohio Valleys to bring another winter system to the
southern Appalachians. High pressure across the Plains states will
help to funnel in cold, sub-freezing air into our region which will
help set the stage in throughout the atmosphere to support snowfall
starting tonight. Overnight there will be a dry layer of air in the
lower levels that needs to be overcome by the incoming precipitation
moving through Tennessee and Kentucky towards the southern
Appalachians. The first uncertainty factor (in this very uncertain
forecast) comes from how fast this drier layer will need to be
precipitated into before saturating allowing snow to reach the
surface.
Once the lower levels saturate, likely sometime early in the morning
across the Cumberland Plateau and southwest Virginia we`ll see
probably the best window for the fastest accumulating snow before
the sun rises and begins to warm up the lower layers of the
atmosphere and to a lesser degree the surface. Models have remained
fairly consistent about tomorrows temperatures rising back above
freezing pretty much everywhere south of Interstate 40 and even
possibly up into the Tri-cities region. Now it absolutely can still
snow with temperatures several degrees above freezing, but the SLR
are much lower and the snow has a higher chance of melting on
contact with some surfaces. This line of above freezing
temperatures/temperatures warm enough to melt the snow remains the
most uncertain aspect of this forecast and we will likely see
reports out of the same county of snow accumulations while other
parts of the county gets all rain... And this is before even
factoring in how the elevation will affect everything. Adding to the
uncertainty is the fact that some very weak downsloping could occur
in the foothills of the western side of the Appalachian mountains.
Downsloping has a history of having a dramatic affect on the amount
and type of precipitation in the foothills, with a swath of light
rain occur just a few miles away from accumulating moderate
snowfall... So during the day on Wednesday have continued with the
trend of lower snowfall totals along the foothills of the
Appalachians. Have stayed close to NBM, WPC, and HRRR snow amounts
as they all seem to be handling the possible melting and downsloping
better than some of the deterministic models.
Ensemble and probabilistic guidance has remained fairly steady with
this being an advisory level event for almost all of the southern
Appalachians with parts of southwest VA and possibly the tops of the
Appalachian mountains having the best chance to see 4+ inches of
snow Wednesday morning through Thursday morning. Forecast confidence
remains highest in the areas that are expected to stay below
freezing along the northern Cumberland Plateau and over into
southwest Virginia. And the lowest confidence in snowfall totals is
for areas along and south of Interstate 40.
OVernight Wednesday night into Thursday morning very cold air will
funnel into the region as we`re under the base of the upper low. And
on the south edge and back side of the low very light lift and QPF
will remain over the region, especially across northeast TN and
southwest VA, as this transitions into a more northwest flow
snowfall event on the back end. An additional 1-2" of snow are
possible in the typically favored orographically enhanced areas of
northeast TN and southwest VA, and we could see closer to 3 inches
in the tops of the Appalachians overnight. The cold air Thursday
morning will be a shock to the system for many as low temperatures
drop into the teens for much of the area, and while winds won`t be
particularly strong, the wind chill values will still drop into the
single digits or sub-freezing along the Cumberland Plateau, enhanced
by the snow pack that will likely be lingering over these areas.
Temperatures will struggle to climb back above freezing anywhere
during the day on Thursday.
&&
.LONG TERM...
(Wednesday night through next Tuesday)
Issued at 300 PM EST Tue Feb 18 2025
Key Messages:
1. Very cold to start the period, but moderating temperatures
thereafter.
2. Outside chance of some flurries/light snow in the north on
Saturday, then some light rain possible on Tuesday. Otherwise,
mostly dry in the long term.
Discussion:
The long term forecast is fairly tranquil and mostly dry.
Thursday night we`ll have to contend with very cold temperatures.
After a day with readings at/below freezing across the board, strong
high pressure will build in from the northwest and allow temps to
drop into the single digits Thursday night into Friday morning.
Friday into Saturday will be dry.
Saturday a shortwave will eject east from the Texas panhandle region
towards the Tennessee valley, moving through our neck of the woods
Saturday evening. Most guidance keeps precip limited to areas north
of us, closer to the parent shortwave and vort max. Will keep PoPs
below the mentionable slight chance levels for now, but wouldn`t be
surprised to see some flurries or light snow across our Virginia
counties and perhaps into the northern Tennessee valley areas Sat
evening.
Late Sat night into the first of next week look dry, with moderating
temperatures beneath WNW upper flow. Should see highs getting back
into the 50s by Monday.
Monday night through Wednesday another system moves through and
should bring additional light precipitation to at least the northern
parts of the CWA. Still a ways out obviously, but this looks like it
would be simply a rain event.
&&
.AVIATION...
(00Z TAFS)
Issued at 632 PM EST Tue Feb 18 2025
Light snow will begin shortly before sunrise, bringing deteriorating
CIGs and Vis. The best chance for IFR conditions and moderate snow
will be in the morning hours. By afternoon, snow will become much
lighter especially at TYS, likely ending at CHA. Light snow will
continue through the afternoon at TRI. A rain/snow mix is possible
in the warmer hours.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 31 40 20 31 / 50 70 10 0
Knoxville McGhee Tyson Airport, TN 29 36 19 28 / 50 80 30 0
Oak Ridge, TN 27 36 18 28 / 70 60 30 0
Tri Cities Airport, TN 27 35 18 25 / 50 90 60 20
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...Winter Weather Advisory from 2 AM Wednesday to midnight EST
Wednesday night for Anderson-Campbell-Claiborne-Grainger-
Hamblen-Hancock-Hawkins-Jefferson-Knox-Loudon-Morgan-North
Sevier-Northwest Blount-Northwest Carter-Northwest Cocke-
Northwest Greene-Roane-Scott TN-Sullivan-Union-Washington
TN.
Winter Weather Advisory from 2 AM Wednesday to 7 AM EST Thursday
for Blount Smoky Mountains-Cocke Smoky Mountains-Johnson-
Sevier Smoky Mountains-Southeast Carter-Southeast Greene-
Southeast Monroe-Unicoi.
Winter Weather Advisory from 11 PM this evening to noon CST
Wednesday for Bledsoe-Marion-Sequatchie.
VA...Winter Weather Advisory from 2 AM Wednesday to midnight EST
Wednesday night for Lee-Scott VA-Washington VA.
Winter Storm Warning from 2 AM Wednesday to 7 AM EST Thursday
for Russell-Wise.
&&
$$
SHORT TERM...
LONG TERM....CD
AVIATION...McD
Area Forecast Discussion
National Weather Service Riverton WY
640 PM MST Tue Feb 18 2025
.KEY MESSAGES...
- Banded convective snow showers will persist across much of western
and central WY through the afternoon. Locally higher amounts are
possible in snowbands, but exact location of these remains uncertain.
- Cold temperatures across northern WY tonight. There is a 70%
chance that low temperatures will reach -15 or lower for much of the
Bighorn Basin and northern Johnson County.
- Another, weaker system brings a chance of light to moderate snow
to western Wyoming Wednesday night into Thursday.
- Drier and warmer from Friday into the weekend.
&&
.UPDATE...
Issued at 629 PM MST Tue Feb 18 2025
Snow bands have increased in coverage this evening, with
moderate snow noted across the southern half of the Bighorn
Basin, Togwotee Pass, and the Wind River Basin eastward into
Natrona County. Radar returns show widespread snow continuing to
push through central Wyoming, which is woefully underdone by
current model guidance. If traveling in central Wyoming this
evening be aware of moderate snow, with reduced visibility and
slick roads. The snow should shift south and taper off over the
next few hours, but it appears to be lingering a little longer
than expected from Cody to Greybull. If clouds hang on a little
longer tonight the result will be slightly warmer low
temperatures across northern Wyoming where the current forecast
is for lows in the 10 to 20 below zero range. Could see that
being more in the 5 to 15 below zero range if clouds hang on for
most of the night.
&&
.DISCUSSION...
Issued at 158 PM MST Tue Feb 18 2025
Snow bands is the word of the day today as a cold front pushes
through the region. The parent trough will slide through the region
today, dragging a cold front with it. The cold front will continue
to bring convective snow bands across the region. These bands
generally have been NW-SE oriented, with limited impacts. The
convective nature of these bands means that it is incredibly
difficult to pin point exactly where they will set up. NAMNest and
HRRR solutions have, however, been fairly consistent with keying in
on a more prominent area of banding from Dubois through Shoshoni and
towards Casper. This would be the most likely area for snowfall
accumulations over 1 inch with a 10% chance of accumulations over 3
inches. Southern portions of the Bighorn Basin along a line generally
from Meeteetse to Thermopolis and perhaps as far east as Tensleep is
the other line where hi-res models have been fairly consistently
keying in on a prolonged period of snowbanding through the
afternoon, and could see amounts of 2-3 inches under those bands
(20% chance).
The concern with any of these bands will be localized higher
snowfall amounts (up to 5 or 6 inches if things set up right (<5%
chance), and brief whiteout conditions. Notably, the snow squall
parameter has been consistently modeled by SPC around 4-5 or "High
threat", and thus, we continue to monitor for localized snow squall
conditions. Greatest concern will be along South Pass and eastern
Sweetwater County later this afternoon and early evening.
Snow will taper off and end overnight as the parent trough slides
eastward into the Plains by Wednesday morning. With clearing skies
behind the front and with fresh snow cover, temperatures will
plummet overnight. There was consideration for Cold Weather
Advisories, however, temperatures will generally remain just warmer
than criteria and it will be a short-lived event, with temperatures
expected to warm up quickly during the day Wednesday. However,
across northern portions of the Bighorn Basin and across northern
Johnson County, temperatures are expected to drop into the double
digits below zero, with a 60% of temperatures below -15F. Winds will
be light, and other than localized colder locations such as Powell,
apparent temperatures will generally stay around -20F through the
night.
Wednesday afternoon, the next shortwave pushes through. The low will
track across northern CO, which would typically be a prime track for
significant snowfall across central WY basins. However, the low is
fairly weak and is not tracking much moisture with it. Much of the
moisture it does have with it will be focused near the low center,
and thus will have limited impact for WY. Though there is a 10%
chance of snow across areas east of the Divide, the main focus for
snowfall in WY looks to be across western and southern WY. Western
mountains could see 4 to 6 inches with locally higher amounts in the
Tetons through Thursday with this event. Though it is hardly
anything compared to the 3 to 4 feet they received over the weekend,
it is worth noting, nonetheless. Across southwest WY along the I-80
corridor, snowfall amounts will generally be light, less than an
inch Wednesday night into Thursday.
After Thursday, the pattern quiets as a ridge builds. This will mean
a break from the active snowy weather and also a significant warm-
up. Temperatures by the later half of the weekend will be well above
normal, with high confidence (80%) in temperatures exceeding 50F by
Monday afternoon for most east of the Divide basins. The exception
would be the Bighorn Basin, where significant snowpack will likely
enhance the cold pool, and thus, could prevent the same degree of
warming there compared to the rest of the region. Still,
temperatures over 40F are still looking likely (70% chance). West of
the Divide basins and valleys also have a 60% chance of seeing
temperatures exceeding 40F by Monday.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 326 PM MST Tue Feb 18 2025
West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals:
Bands of snow continue to spread across KJAC this afternoon.
Radar notes showers remain lined up upstream of KJAC, so
extended TEMPO grouping into the evening. A couple of these snow
showers may clip KBPI/KPNA, but only into early this evening as
all showers begin to weaken. Midlevel BKN cloud decks remain in
place at KRKS, and thicken back up at KBPI/KPNA/KJAC overnight
after snow chances have ended. Skies remain partly to mostly
cloudy overnight, but will be mainly mid to high level cloud
decks through the day Wednesday.
East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals:
Snow bands continue to sweep southeast today at or near all
sites. Snow will vary at all sites through around 06Z, when the
system progresses to the southeast. Skies will gradually clear
between 06Z and 12Z, with most sites only seeing SCT high level
layers after 12Z. Winds remain light from the north during the
day, generally under 10kts.
&&
.RIW WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 11 PM MST this evening for WYZ001-
002-012-024.
&&
$$
UPDATE...Rowe
DISCUSSION...Hensley
AVIATION...Straub