Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/07/25
Area Forecast Discussion
National Weather Service Denver/Boulder CO
858 PM MST Thu Feb 6 2025
.KEY MESSAGES...
- Warmer Friday over the urban corridor and plains.
- Snow will move across the mountains Friday night, likely
producing slippery roads Saturday morning.
- Another round of mountain snow Saturday night/Sunday. Some of
this snow may spread east onto the plains.
- Another shot of cold will affect the plains early next week
along with a good chance of light snow Monday night into
Tuesday.
&&
.UPDATE...
Issued at 851 PM MST Thu Feb 6 2025
Relatively quiet conditions across the region this evening. No
significant changes were made the grids tonight as things were
largely on track. Will let the night shift decide if warmer temps
are needed for the metro tomorrow afternoon, as some early
guidance tonight has highs in the low to mid 60s.
&&
.SHORT TERM /Through Friday/...
Issued at 240 PM MST Thu Feb 6 2025
Mostly clear skies will continue into the evening hours. Mid
level moisture begins increase late tonight in advance of the next
shortwave trough. There looks to be enough moisture to bring
isolated snow showers to the northern mountain late tonight and
into Friday. Snowfall amounts will be light with any accumulation
through Friday afternoon being less than 2 inches.
A lee-side trough deepens through the day Friday at the base of
the foothills ahead of the approaching shortwave trough. East of
the surface trough across the eastern plains, south to southwest
winds are expected to prevail which should lead to the development
of a Denver Cyclone. The HRRR and most of the HiRes models show
gusty west winds mixing down and spreading east across the plains.
With the lee-side trough at the base of the foothills, neutral to
slight warm air advection, and the expected formation of the
Denver Cyclone, do not expect widespread gusty west winds across
the plains. Still could end up with scattered areas of gusty winds
mixing down. Where better mixing occurs (mountains and
foothills), wind gusts of 50 to 60 mph will be possible.
Temperatures will be mild with highs in the 50s across northeast
Colorado. Lower to mid 60s will be possible where the stronger
westerly downslope winds occur.
&&
.LONG TERM /Friday night through Thursday/...
Issued at 240 PM MST Thu Feb 6 2025
Looks like a fairly active extended period, with multiple chances
for mountain snow, and even some light snow pushing east onto the
plains as persistent westerly flow aloft remains in place through
early next week.
Things will kick off Friday night as increasing westerly flow aloft
is expected as a 250mb level 150-170kt jet max slides east and over
northern Colorado. At 500mb, a shortwave embedded in the flow will
pass over the Rockies, and a surface cold front will push across the
forecast area from north to south. QG fields show persistent upwards
ascent and fairly strong frontogenesis through early Saturday
morning. Cross sections show increasing moisture from west to east,
stretching from the surface, topping 500mb over the high country
overnight. Ingredients will be in place to support orographic
snowfall for the northern and central mountains with additional
support from the QG forcings. Snow is expected to start in the
northern mountains Friday evening before pushing south to the I-70
mountain corridor by midnight. We expect some slick travel
conditions for the evening commute in areas across the northern
mountains such as Rabbit Ears Pass, and with winds gusting to 60 mph
across our higher elevations, blowing snow may reduce visibilities
to as low as a 1/4 mile at times; therefore we have issued a Winter
Weather Advisory beginning at 5PM Friday night through 7AM Saturday
morning for western Jackson and Grand Counties where 6 to 12 inches
of snow are expected, with some locally heavier amounts possible.
With the heaviest snowfall expected between midnight and 5AM, there
may be some lingering impacts to Saturday morning`s ski traffic
along the I-70 mountain corridor and US-40 over Berthoud Pass. As of
now, it`s looking like highlights won`t be needed for these
locations, but will continue to assess as new guidance comes out.
Cross sections show drier air moves in for the day on Saturday, and
cooler temperatures will be in place behind the aforementioned cold
front. High temperatures across the eastern plains are expected to
remain in the 30s, with downslope winds keeping milder temperatures
hugging the base of the foothills and adjacent plains. Light snow
showers will be possible throughout the day in the mountains.
Another disturbance in the westerly flow aloft is expected to pass
across the Rockies Saturday night. At the surface, easterly flow
will develop that will bring a period of upslope conditions to the
eastern slopes of the Front Range Mountains, that will bring a
chance of light snow to the lower foothills and adjacent plains.
The active pattern continues into next week with the best shot at
accumulating snowfall for the lower elevations being Monday night
into Tuesday as flow aloft transitions to a more WSW regime ahead of
an approaching trough and another cold front dips down into
Colorado, bringing a return of upslope flow for the Front Range.
While details are still getting ironed out with exactly how this
system will play out, ensembles seem to agree that moisture will
make it to the lower elevations, but just how much is still unknown.
The NBM PoPs seemed reasonable at this point, so let those ride from
Monday onward. Below normal temperatures are expected through the
extended period.
&&
.AVIATION /00Z TAFS through 00Z Saturday/...
Issued at 427 PM MST Thu Feb 6 2025
VFR expected through the TAF period. A well defined Denver Cyclone
is ongoing this afternoon, with some fairly strong easterlies at
DEN with weaker N/NW at BJC/APA. That cyclone should lift
northeastward this evening, with DEN eventually transitioning to
some sort of northerly component with lighter speeds.
Drainage should establish later this evening, and will likely
continue through the morning hours Friday. A little more
uncertainty in the wind forecast Friday. Some guidance suggests
another cyclone which would keep winds more southeasterly, while
others mix stronger westerly flow to the terminals. Ended up going
with a middle ground solution with some WSWerly flow with speeds
around 10-15kt.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 5 PM Friday to 7 AM MST Saturday
for COZ031.
&&
$$
UPDATE...Hiris
SHORT TERM...Meier
LONG TERM...Bonner
AVIATION...Hiris
Area Forecast Discussion
National Weather Service Boston/Norton MA
1024 PM EST Thu Feb 6 2025
.SYNOPSIS...
Dry and windy weather Friday with higher gusts across the higher
elevations spots. Winds diminish Friday night with colder
conditions into Saturday. A snow storm appears likely later
Saturday night into Sunday morning, with perhaps some mixing for
some locations towards the end of the storm, especially near
the south coast. Dry but cold weather returns Sunday night and
Monday. This active weather pattern may continue next week
depending on the track of a couple low pressures in the Tuesday
through Thursday time frame.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
10 PM Update...
No major changes at this time. Latest forecast continues to be
on track. Low clouds expected to thin out slowly tonight as
winds from the SW have started to pick up a bit.
Key Messages...
* Low Clouds/Patchy Fog very slowly burnoff overnight
* Temps steady or slowly rising into the lower-middle 30s
Low pressure will continue to lift northeast into the Canadian
Maritimes tonight. This will result in winds shifting to the
southwest...but low clouds and fog patches will be slow to burn
off especially towards the Cape and Islands. However...we do
expect most locations to see the bulk of the low clouds depart
toward morning. As the winds shift to the SW...the shallow cold
air that has been in place will mix out a bit especially across
the interior. This will result in temps steady or slowly rising
in places...particularly where temps still were in the 20s
across the interior. Temps by daybreak should mainly be in the
lower to middle 30s. Winds will become gusty toward morning
too...so not a black ice setup.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Key Messages:
* Gusty west winds starting Friday morning, especially over the
higher elevations.
* Wind Advisory for west, central MA.
* Mainly dry conditions with a chance for a snow shower in west
MA.
Strong CAA and a LLJ will support the mixing down of gusty west
winds to the surface starting early Friday morning. This happening
in the early morning timeframe could be a limiting factor as mixing
isn`t diurnally supported. However, the appearance of well-mixed
model soundings, a strong gradient of cold air pushing into the
region, and a pressure couplet should support winds to mix down. The
higher elevations will be most vulnerable to the higher gusts
starting with the Berkshires early Friday morning and then the
Worcester Hills by late morning. Given the perpendicular flow to the
"terrain", could see some downslope enhancement off the east slopes
of the Berkshires. Most model guidance is overall trending low for
gusts with this event. The HRRR, which does quite well with complex
terrain, shows a signal for strong gusts in these areas Friday.
Won`t put all of our eggs in one basket as the HRRR does have a
tendency to over mix in some situations too... Blended in the
NBM 90th percentile to better represent this potential solution.
We should see gusts in the 40-50 mph across west and central
MA. A Wind Advisory will cover those areas from 4 AM through 4
PM. Winds may not consistently gust to that magnitude all day
with a better signal for stronger gusts in the Berkshires
starting early morning (after 4AM) and a better signal for the
Worcester Hills by mid-morning.
Areas not in the advisory will be generally gusty with gusts 20-35
mph. High temperatures range in the 30s. Can`t rule out a snow
shower western MA.
Friday Night:
Quiet night with high pressure building in. Soundings show some
moisture in the mid-levels to support scattered clouds around, but
otherwise dry. Temperatures falls into the teens and low 20s.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Key Messages:
Key Messages...
* Dry and partly to mostly sunny on Saturday.
* Snowstorm moves through Saturday night through Sunday morning.
* Another winter storm possible around Tue night/Wed
Saturday...
Quiet, dry, and mostly sunny conditions expected for the first half
of the weekend as high pressure from the Great Lakes moves directly
over New England. Subsidence will keep precip away and allow for
partly to mostly sunny skies while the light pressure gradient will
mean Friday`s winds calm down by Saturday. While conditions start
out sunny, high clouds will be on the increase through the day ahead
of the Saturday night system. Highs will be just on the cool side of
average for early February, in the low to mid 30s.
Saturday night and Sunday...
As we head into Saturday night a shortwave moving out of the Midwest
will transit east with a strengthening surface low out ahead of it.
By Saturday evening a secondary low is spawned along the frontal
boundary which becomes dominant and deepens over the waters south of
Long Island before passing in the vicinity of the 70/40 benchmark.
This placement, if it holds, would be favorable for a significant
snowfall over much of southern New England as long as everything
lines up. Given we are more than 48 hours out, the exact track isn`t
certain as we`re just starting to get into the range of the higher
resolution guidance. The latest deterministic global guidance is in
good agreement on a track over the benchmark; however, EPS ensemble
guidance indicates a decent spread on low locations (tightly
clustered south of Long Island but spreading out quite a bit more as
it passes south of Nantucket). Meanwhile, GEFS member lows are all
near or south of the benchmark, so we`ll see if the southward trend
of the last few days continues. For now, ingredients appear to be
lining up for a solid snow maker, with strong southwesterly WAA and
significant low/mid level frontogenesis coupled with a PWAT plume
from 0.5-0.75". There`s plenty of cold air locked in with a high to
the northeast; BUFKIT soundings indicate decent omega within the DGZ
which would lead to better snowfall rates. Snow-to-liquid ratios
will be above 10:1 given the deep cold through the column. Should
these ingredients continue to align with a favorable track, a solid
swath of 6+ inches of snow is possible. The biggest question is if
the southward trend in the track is done or if we`ll continue to see
it sag south which would decrease snow totals north. The latest
suite of ensemble guidance indicates a 40-80% chance of 6+inches for
most of the region. Snow exits Sunday morning and we`ll see clearing
and drying through the day.
Monday through Thursday...
A ridge of high pressure brings the return of quiet weather for the
start of next week with seasonable high temperatures topping out in
the low 30s but lows in the teens. Monitoring our next potential
system then around Tuesday evening into Wednesday as a low passes in
the vicinity of the 70/40 benchmark and may bring accumulating snow
to the region before another high pressure center moves overhead
followed by yet another shortwave disturbance around Thursday. While
details are uncertain, what is more certain is that our active
pattern continues.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
Forecast Confidence Levels:
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
00z TAF Update...
Low pressure lifts into the Canadian Maritimes tonight. The
result will be winds shifting to W/SW which will bring
improvement to cigs/vsbys...albeit slowly. IFR-LIFR should
improve to mainly MVFR toward or a bit after midnight. Then we
should see mainly VFR conditions finally arrive toward daybreak
Fri as clouds scatter out along with increasing W/NW winds,
gusting as high as 30-40 kt during the day. Winds gradually
subside Fri night.
KBOS TAF...High Confidence in trends, but lower confidence in
timing.
KBDL TAF...High Confidence in trends, but lower confidence in
timing.
Outlook /Saturday through Tuesday/...
Saturday: VFR.
Saturday Night: Mainly IFR, with local MVFR possible. SN.
Sunday: MVFR/IFR conditions possible. Breezy. SN.
Sunday Night through Monday Night: VFR.
Tuesday: VFR. Chance SN.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High- greater than 60 percent.
Overall high confidence through the weekend.
Winds increase late tonight into Fri morning as mixing layer
deepens. Strongest gusts to Gale force are expected on the
waters off E MA coast, mainly across our open waters. Elsewhere,
forecast soundings indicate gusts overall will mainly be just
short, but may still be a few 35 knot wind gusts. Felt strong
SCA headlines were the way to go in these waters. Winds and seas
subside Fri night as high pressure builds into region from
Great Lakes.
The next system to watch is a potential winter storm for the Sat
night into Sun timeframe, when low pressure is expected to track off
SNE coast, most likely near 40N/70W benchmark Sun morning. Right now
the storm is not expected to strengthen significantly, but will
likely bring SCA conditions to most of the MA/RI waters.
Outlook /Saturday through Tuesday/...
Saturday: Winds less than 25 kt. Seas locally approaching 5 ft.
Saturday Night: Winds less than 25 kt. Chance of snow, chance
of rain. Areas of visibility 1 nm or less.
Sunday: Winds less than 25 kt. Seas up to 5 ft. Chance of snow,
chance of rain. Visibility 1 to 3 nm.
Sunday Night: Winds less than 25 kt. Seas up to 5 ft. Slight
chance of snow.
Monday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Monday Night: Winds less than 25 kt.
Tuesday: Winds less than 25 kt. Chance of snow.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Winter Storm Watch from Saturday evening through Sunday
afternoon for CTZ002>004.
MA...Winter Storm Watch from Saturday evening through Sunday
afternoon for MAZ002>022-026.
Wind Advisory from 4 AM to 4 PM EST Friday for MAZ002>004-
008>012-026.
RI...Winter Storm Watch from Saturday evening through Sunday
afternoon for RIZ001>007.
MARINE...Small Craft Advisory from 4 AM to 7 PM EST Friday for ANZ230-
236.
Small Craft Advisory until 1 AM EST Saturday for ANZ231>235-
237.
Gale Warning from 4 AM to 6 PM EST Friday for ANZ250-251-
254>256.
&&
$$
SYNOPSIS...BW/Mensch
NEAR TERM...Frank/Hrencecin
SHORT TERM...Mensch
LONG TERM...BW
AVIATION...Frank/BW
MARINE...BW/JWD
Area Forecast Discussion
National Weather Service Columbia SC
853 PM EST Thu Feb 6 2025
.SYNOPSIS...
Expect well above normal temperatures through the weekend with
near record highs possible. A series of weak disturbances and
weak fronts will promote a chance of showers through much of the
extended.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Key Message(s):
- Cloud cover decreases and temperatures above normal.
Mostly clear skies across the Midlands and CSRA this evening with an
area of convection well off to the northwest associated with a cold
front. The flow aloft remains nearly zonal, but a couple of weak
short wave troughs moving east of the Mississippi may continue to
provide a weak source of lift for the convection moving out of the
Appalachians. will move across the Carolinas overnight to provide
some lift. The HREF suggests a few showers mainly in the SC Piedmont
into the north Midlands overnight, so will maintain a low chance in
those regions. Otherwise, dry conditions expected overnight with
elevated boundary layer winds due to a low level jet near 30 knots.
This will also contribute to warm overnight low temperatures,
generally only around 60 degrees.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
Key message(s):
- Low rain chances for Friday afternoon and evening
An upper level trough will lift out of the Northeast on Friday
with a nearly zonal flow behind the system. At the surface a
weak cold front sags into the region and then stalls across the
forecast area (FA). A westerly wind profile and weak moisture
advection does not favor widespread showers. PWAT values o
around just over 1 inch and some weak convergence along the
front may support some scattered showers through the day and
evening hours. South of the boundary there will be some weak
instability and a slight chance of a thunderstorm but little
risk of sever weather. The stalled boundary is forecasted to
move north during the day on Saturday. This will likely produce
quite a range of temperatures from north to south.
Highs across the southern half of the FA will be near 80
degrees but further north may remain in the low 70s due to
higher cloud cover and possible showers nearer the front. Any
shower activity could continue into Friday night as the front
continues to slowly sag southward. Any rainfall amounts will be
light. Lows will be above normal, from the low to mid 50s. Highs
on Saturday will likely have an even larger spread from north
to south depending on retreating boundary.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Key Message(s):
- Record high temperatures possible Sunday
Well above normal temperatures expected across most of the FA on
Sunday with the front lifted well north of the FA. Highs in the
mid 70s to low 80s may again approach record values (81 at CAE
and AGS). Rain chances through the day appear on the lower side,
but we can not rule out some isolated shower development ahead
of the next front which may backdoor into the region late
Sunday.
Lots of uncertainty remains for the long term period of the
forecast. As a large spread in model guidance remains in the
projections for next week. A series of reinforcing cold fronts
will push into the Carolinas and stall as troughs move through
the upper levels well to our north. Whether these fronts make it
through the FA remains to be seen. In general IQR ranges from
the NBM for the end of the long term remain around 20 indicating
a lack of confidence in the positioning of any frontal
boundaries. With the potential for a front near or over the FA
through much of the long term and mean PWAT values from the GEFS
and ECMWF steady from 1 to 1.25 there will be at least a chance
of rain most days in the extended. Temperatures will likely
remain near or above normal for the period for highs and likely
above normal for lows giving the clouds and chances for
rainfall.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
Generally VFR expected. MVFR ceilings expected toward morning.
Mid-level clouds, generally between 4000 and 5000 feet, have
developed across central GA and are moving into our forecast
area. They should overspread the TAF sites over the coming hours
but generally remain VFR for most of the night. An active
pattern focused to our north should push another front towards
the area by tomorrow morning with an increase in low-level
moisture expected ahead of it. Guidance continues to indicate
the likelihood of at least MVFR ceilings developing after
09z-10z at the CAE/CUB sites and then expanding southward. LAMP
guidance is the least aggressive with this but even it is still
showing widespread MVFR at AGS/DNL/OGB. IFR is possible, as
shown by guidance like the HRRR & CONSShort, but confidence is
not high enough to include it as anything but a TEMPO group. It
is expected that clouds will begin to clear by late morning or
early afternoon as that front slowly sags through the area.
Clouds may also just lift, which would leave us with ceilings in
lower end of VFR or upper end of MVFR. Winds are expected to
remain up as strong low-level flow develops overnight. So look
for westerly winds with speeds in the 5-10 knot range throughout
the period.
EXTENDED AVIATION OUTLOOK...Periodic showers over the weekend
could cause restrictions at times. Low ceilings possible Monday
into Tuesday.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.
&&
$$
Area Forecast Discussion
National Weather Service Goodland KS
408 PM MST Thu Feb 6 2025
.KEY MESSAGES...
- Freezing fog still forecast (70% chance of fog), dense
possible (25%). Fog overall is favored mainly along and south
of Interstate 70.
- Breezy to gusty winds of 35-45 mph Saturday behind a cold
front.
- Increasing chances for colder temperatures and light snow
potential to start next week.
&&
.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 1250 PM MST Thu Feb 6 2025
Backdoor cold front has moved through the area resulting in
subsidence across the region leading to the clear skies across the
area. High temperatures remain forecast in the 40s for the entire
forecast area for the day. A surface high draped across the eastern
2/3 of the area will lead to light and variable winds. As the high
slowly moves away from the area winds will begin to shift to the
ESE.
As winds turn to the ESE weak moisture advection will begin to work
its way back into the region resulting in increasing fog and stratus
potential across the area. Ongoing stratus and fog in southern
Kansas and across Oklahoma will be the source region for this
moisture advection. A few key variables still need to be worked out
to see if this is stratus vs fog or a combination of both. RAP and
the HRRR continue to remain the most aggressive with the moisture
return tonight leading to dense fog potential from roughly a
Stratton, Colorado to Cheyenne Wells, Colorado line and on east.
There area also some hints that it may extend further north into
Nebraska as well. Then there is the NAM which
uncharacteristically like has the moisture advection delayed
and weaker leading to stratus and lesser fog coverage favoring
Highway 40 on south from Weskan to eastern Logan county. The
part that makes me not able to completely discard the NAM and
does bring some concern about the current fog forecast is that
the NAM is currently handling the dry dew points in the single
digits better than the RAP and HRRR which again is interesting
as the RAP and the HRRR favor a drier bias. So with all of this
said confidence in fog has decreased some but will continue with
the mention in the forecast. The current forecast is directed
towards the RAP/HRRR just given the favored southeasterly
upslope pattern.
A segue into the next variable for fog vs stratus formation is
that a surface trough will move west to east across western
portions of the forecast area which will have winds shift to the
southwest (unfavorable for fog) and increase winds to around
20-30 mph briefly which may disrupt the fog formation or
decrease the coverage. At this time based on recent HREF and
HRRR wind solutions the favored area for this potential is
roughly along the I-70 corridor which is the main reason for
keeping to fog wording as patchy up in that area. Also am seeing
a consistent signal for some patchy drizzle or freezing drizzle
around the Graham/Sheridan counties area around the 8-10am CT
time frame as RAP has been slowly increase the 0-1KM moisture
but right along the western periphery of some lift. Confidence
is less than 5% in this occurring so will be leaving out of the
forecast for now due to the weak signal and limited spatial
extent of the threat.
Friday, overall pattern trends look to be similar to yesterday with
clear skies pushing in from the west and pushing any fog and stratus
out of the area and warming fairly quickly. Where the stratus and
fog does end up at will be slower to warm and depending how quickly
it fades will be dependent on how warm temperatures get in that
area. As a result have trended high temperatures down across
portions of Thomas, Logan, Gove and Wichita counties due to
this potential. Elsewhere highs in the upper 40s to low 50s
across east Colorado remain forecast. Friday night a continued
resurgence of fog and stratus may return to eastern portions of
the area again. Will be watching a stronger cold front to move
across the area again Friday night and into Saturday morning
that will usher out the moisture for any additional fog
issues.
Saturday, have started the process of bringing temperatures
down as GEFS members are all in fairly good agreement with
bringing the front through quicker. There does appear to be a
slight recovering in 850mb temperatures during the afternoon
which may help in containing how far temperatures do fall. High
temperatures are currently forecast in the mid to upper 30s
across the area. During the afternoon a quick moving shortwave
off of the Rockies may bring some light snow potential to the
northwest portion of the forecast area. However, I do have some
concern about the air at the surface being to dry so have nudged
back pops towards slight chance (24%) to account for this
potential. At this time little if any snow accumulation is
currently forecast and expected.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Issued at 245 PM MST Thu Feb 6 2025
A broad upper trough will be carved out across the central CONUS
this period. This will result in below normal temperatures as
well as occasional chances for snow.
Temperatures will be slightly below normal Sunday and Monday,
falling to much below normal on Tuesday and Wednesday with
Arctic air settling into the area and plenty of clouds, and
possibly remaining below normal into Thursday as the Arctic air
will be slow to move out. There are low probabilities, around
20%, of meeting cold weather advisory criteria Wednesday and
Thursday mornings with wind chills in the 10 to 15 below range
currently forecast.
Snow chances increase Monday afternoon and especially Monday
night as the Arctic front moves through. Snow will continue
through Tuesday with possibly a break Tuesday night, but then
pick up again Wednesday with another shortwave moving through.
Thursday currently looks dry. Several inches of snow will be
possible in the Monday through Wednesday time frame. Impacts
will be mitigated somewhat by being spread out over several
days. Winds do not appear to be a concern at this time. Low to
moderate impacts associated with bitterly cold temperatures and
light snow will be the main concerns.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 400 PM MST Thu Feb 6 2025
For KGLD... VFR conditions are forecast for most of the period,
but IFR visibilities and ceilings are possible between 06-18Z.
Similar to a couple of nights ago, fog and low stratus clouds
are forecast to develop and move slowly to the east during the
late night and morning hours. The signal is a little weaker this
time, so am currently thinking that fog would only get to around
a mile visibility and linger for only an hour or two. That being
said, the earlier the fog and clouds form, the more persistent
and denser they will be. Best timeframe looks to be between
13-16Z, but be cautious after 06Z. Winds near the surface will
remain from the southeast through the period, with speeds
picking up to around 10-20 kts during the day tomorrow. Clear
skies are expected once the fog/low clouds pass.
For KMCK... VFR conditions are currently forecast for the
period, but there is a chance for fog to briefly move over the
terminal between 09-20Z. The best chance should be between
14-18Z if the fog or low stratus clouds formed. Visibilities
could drop to around a mile with ceilings around 200-400ft.
Overall chance looks to be around 30% as there is a question of
how far north the moisture will push. Otherwise, winds near the
surface will remain from the southeast with speeds around 5 kts
overnight, and then 10-15 kts during the day.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.
&&
$$
SHORT TERM...Trigg
LONG TERM...024
AVIATION...KAK
Area Forecast Discussion
National Weather Service Grand Rapids MI
955 PM EST Thu Feb 6 2025
.KEY MESSAGES...
- Impactful winds through this evening
- Storm system with potential impacts Saturday into Saturday night
&&
.UPDATE...
Issued at 955 PM EST Thu Feb 6 2025
Added low chance POPs along and north of I-96 as lake effect snow
showers can be expected in west flow with some saturation of the
DGZ and inversion heights around 5 to 6 kft. Drying and
subsidence should end the snow showers after midnight.
&&
.DISCUSSION...
Issued at 228 PM EST Thu Feb 6 2025
- Impactful winds through this evening
Models continue to show impressive 925/850 mb winds for the
remainder of the afternoon and into the evening. Upstream VWP`s
in WI confirm the 50 to 55 knot winds at 850 mb that the models
have been predicting would occur. The winds at 925 are not as
strong with 25 to 45 knots based off of VWP`s but the HRRR and
other models strengthen them up closer to the 45 to 50 knot range
as the core of stronger winds pull through around 00z. It appears
we will mix up to around 925 mb, and perhaps higher but not quite
to 850 mb. This increasing mixing height is the result of
strengthening cold air advection. Also, model cross sections show
a trop fold potential with this wave moving in from the west which
commonly leads to very winds conditions at the surface. Mid to
upper level WV imagery shows this wave well. Based on all this,
advisory strength winds are forecast to prevail for much of the
region into this evening. DESI suggests the potential for 60 mph
winds is too low to change the headlines. The far southeast parts
of the CWA are not in a wind advisory. The 18z HRRR suggest the
best potential for winds over 40 knots is where we currently have
the headline out. Thus no changes at this time. We will need to
monitor the upstream winds in WI as those values may indicate how
strong the winds will be in MI.
- Storm system with potential impacts Saturday into Saturday night
There`s still uncertainty how this weekend storm system will
impact the region. The upper level support has weakened somewhat
with this system. The associated moisture advection is shown to
be not as strong as well. However we still end up with deeper
moisture during the day along with some lift that will support an
area of accumulating snow. Most indications are that our northern
zones will be favored for the longest duration of steady snow as
moisture profiles there feature a longer period of deeper
saturation. Southern zones are likely to see the DGZ dry out,
which will act to cut back the qpf. DESI probs for greater than 4
inches are quite low for much of the CWA, under 30 percent, with
the highest potential over the northern parts of the CWA. Thus we
will feature the highest amounts up towards Ludington, Evart and
Harrison.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 646 PM EST Thu Feb 6 2025
We have seen the clearing of the lower clouds progress from North
to South over the last few hours. This has brought VFR conditions
to all of the terminals. We can expect this clearing to hold for a
few hours. The arrival of the colder air will be accompanied by
lower MVFR clouds returning, and very gusty winds. Wind gusts
exceeding 40 knots are likely at almost all of the sites, with
less of a chance further SE toward KJXN. Winds will peak through
about 03-06z before gradually tapering off.
The lower clouds will then hold once they move back in through the
night and through much of Friday. They are expected to lift to VFR
toward afternoon. Some of the SE sites could even see clearing
mid-late afternoon as the winds become from the SW.
&&
.MARINE...
Issued at 228 PM EST Thu Feb 6 2025
Given the forecast mixing heights and winds at those levels,
gusts in the 40 knot range are looking likely for the nearshore
waters through the evening. A few gusts may reach into the storm
force category but they are expected to be brief. The winds
diminish steadily later tonight into Friday as the pressure
gradient weakens.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Wind Advisory until 1 AM EST Friday for MIZ037>040-043>046-
050>052-056>058-064-065-071.
MARINE...Gale Warning until 4 AM EST Friday for LMZ844>849.
&&
$$
UPDATE...Ostuno
DISCUSSION...MJS
AVIATION...NJJ
MARINE...MJS
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
534 PM CST Thu Feb 6 2025
.KEY MESSAGES...
- Drizzle and/or light rain is likely late Friday through
Saturday. There will be a wide range in temperatures from north
to south with a slight (20% or less) chance for precipitation
to very briefly fall as freezing drizzle in northeastern
Missouri Saturday morning.
- A cold, active pattern is looking plausible heading into next
week, which includes the potential for accumulating snowfall
Monday into Tuesday with additional snowfall into midweek.
&&
.SHORT TERM... (Through Late Friday Night)
Issued at 238 PM CST Thu Feb 6 2025
There two features to watch over the next few hours: The surface
front/trough extending east to west from southern Kentucky to the
Missouri/Arkansas border and the surface high over the central
Plains.
Visible satellite imagery provided a nice spectacle of the
boundary early this morning with a fine line of cumuliform clouds
embedded within the stratus deck. The feature was sinking very
slowly to the south, if not already stationary. Another weak
shortwave is riding along this boundary from west to east, which is
providing a slight northward push in the mid to high cloud cover
over southern sections of Missouri. Drizzle and a few spotty showers
are possible through late this afternoon in these areas.
Surface high pressure over the central Plains will continue to build
eastward later today through the day Friday. The surface high is
effectively scouring out low level moisture with clearing from
northwest to southeast. The most noticeable change will be the loss
of cloud cover this afternoon in most areas with exception to far
southern locations in the CWA. There is a secondary cold front that
extends southward from low pressure over Canada, but airmass loses
southward momentum with a west/east orientation in the isotherms.
Light/calm winds and clearing skies will give way to overnight
temperatures that run approximately 5-7 degrees cooler than last
night. Considering light winds, the lack of cloud cover and the
waffling boundary, it is possible that patchy fog will develop
somewhere along the boundary. The HRRR/RAP show some semblance of
visibility reductions with the RAP being a little more aggressive in
spots around central Missouri. Mostly light, patchy fog is possible
south of I-70 with localized, relatively dense(r) in close
proximity to the boundary. Lows Friday morning ranging from the mid-
20s in northern Missouri and west-central Illinois to the north to
the low-30s over southwestern Missouri.
High pressure remains in control as it traverses west to east
across the mid-Mississippi Valley Friday. By late afternoon/evening,
the high shifts to the east resulting in veering surface flow out of
the southeast by Friday evening. Chances for precipitation will rise
slowly Friday evening into Friday night. This system looks very
similar to the recent system that brought drizzle and light rain. A
upper level shortwave embedded within the west/east flow pushes into
the central Plains with cyclogenesis east of the central Rockies. As
the system approaches, warm air advection will begin to lift the
boundary northward with a slow advancement in moisture from
southwest to northeast, albeit limited to the surface and mid
levels. Moisture depth decreases from south to north with a dry
surface layer below the shallow saturation aloft. This suggests
precipitation will initially have difficulty making it into the
colder regions of northern Missouri and west-central Illinois to
result in any precipitation type issue Friday night. Expected clouds
to increase with drizzle/rain chances rising along and south of I-44
in Missouri and along and south of I-64 in Illinois.
Highs Friday will largely be in the 40s with lows Friday night
falling into the 30s.
Maples
&&
.LONG TERM... (Saturday through Next Thursday)
Issued at 238 PM CST Thu Feb 6 2025
Saturday starts out the long range in soggy fashion with drizzle and
spotty patches of light rain about the area. As noted in the short
term section, the system looks quite similar to the system earlier
in the week with a slight shift to the north. Moisture is relatively
higher over the southern sections of the CWA with model soundings
showing saturation at or below 850 MB and dry air aloft. Working
north of I-70, moisture depth is far more shallow and suspended
between 850-800 MB. The initial gap between dewpoints/temperatures
close between 12z-18z, when the column eventually saturates.
The previous information is important because temperatures initially
start out near freezing in a line from Shelby and Marion Counties
(MO) to Adams County (IL) before rising above freezing Saturday
morning. If drizzle materializes early enough, 1-2 hours of light
freezing drizzle is possible. Latest LREF probabilities show 40-50%
of the ensemble members with a light glaze running from La Plata, MO
eastward through Quincy, IL. However, I`m cautious in broad-brushing
this entire area with this potential considering the borderline
temperatures. This does not look like a huge concern with a tight
window in time and the northward advancement of milder air -
maintained the 20% or less wording given the uncertainty. That
being said, the frontal boundary will meander across the region as
the system tracks west to east, resulting in a wide range in high
temperatures. Ensembles have begun to get a better grip on things
with low to mid-60s over far southeastern Missouri and mid-30s
over northern Missouri and west- central Illinois.
Cold air is reinforced to the south behind a cold front that trails
the departing system. This time, the airmass become well-established
with a strong surface ridge that build southeast out of the northern
Plains. This could end up spelling trouble, though, with the pattern
remaining active into next week. Yesterday, I`d mentioned the zonal
upper flow pattern that is conducive for embedded, weak upper
vorticity that moves progressively through the mean flow. The
surface to mid-level ridge remains locked in over the southeast
CONUS, extending westward into the western Gulf, becoming the focus
for surface/mid-level vorticity and moisture to be steered northeast
out of the southern Plains and into the Midwest around the ridge`s
northern periphery and over top the surface boundary.
The first of such upper waves approaches late Sunday into Monday,
but lacks organization and overruns dry air at the surface and mid-
levels. Low precipitation chances (15-20%) are introduced to
central/southeast Missouri by early Monday morning, it is with the
caveat that this is an artifact of NBM model spread and will be one
of the details that will have to be worked out in time. If
precipitation does fall anytime Monday, it`s almost certain to be
snow with sub-freezing air aloft, saturation, and modest lift within
the dendritic growth zone.
The best best potential arrives late Monday into Tuesday, when
troughing develops to the west and a cutoff upper low kicks out of
the southwestern CONUS. This sends waves of vorticity ahead of the
parent wave and provides ample, broader upper lift over a mid-level
trough axis that extends west to east across Missouri/Illinois. The
surface boundary remains well to the south with cold air in place,
as moisture is hurled northward around the western periphery of
the southeastern ridge. All of this shows at least some potential
for winter weather late Monday through much of Tuesday. While
there is not nearly enough confidence to make any determination on
specifics, it does show the possibility for an impactful winter
event. It also looks similar to the early January system in the
sense that it`s an I-70 system and while not an impressive, deep
system, the west-east orientation and track of the system would
result in an extended residence time for waves of precipitation to
pan out somewhere over the region. GFS/ECMWF ensembles all show
some level of accumulation with a wide spread from just a couple
of inches to above warning criteria (5+ inches). Again, these
specifics cannot be nailed down this early, but merely an early
heads-up to keep an eye on the forecast as we head through the
weekend. This will certainly be one to watch in the coming days.
The remainder of the week continues to look wintry. Despite an
increasing spread in temperatures, the upper quartile of the NBM
guidance shows highs ranging from the upper 20s to mid-30s beyond
Monday. There are additional chances for snow through midweek with
multiple waves moving across the region. While specifics are
uncertain, the cold, wintry theme is looking plausible.
Maples
&&
.AVIATION... (For the 00z TAFs through 00z Friday Evening)
Issued at 533 PM CST Thu Feb 6 2025
Dry and VFR flight conditions are expected to persist through Friday
evening at all terminals with winds becoming northeasterly and then
easterly during the day. A few sprinkles are possible as early as
Friday afternoon, but confidence is high that impacts from
precipitation and low ceilings will not occur until Friday
night, beyond the TAF period.
Pfahler
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Marquette MI
608 PM EST Thu Feb 6 2025
.KEY MESSAGES...
- Very strong winds and snow showers will create blizzard
conditions in Ontonagon, Baraga, Houghton, and Keweenaw
counties this afternoon and evening. 50+ mph winds, blowing
snow, and whiteouts will be possible, especially in snow
showers. These will create dangerous travel conditions.
- Gusty winds of 30-40 mph will be possible elsewhere this afternoon
and evening. This will result in patchy blowing snow.
- Lake effect snow showers this evening and tonight will support 3-5
inches of snow in the snowbelts of Alger, Luce, and northern
Schoolcraft counties.
- Only one system snowfall is expected over the next 7 days,
occurring Saturday into Saturday night. This is not expected
to be a significant snowfall and will primarily impact the
south central U.P. with a few inches of snow and some
slippery travel conditions.
- Temperatures around normal to a little below normal through
this weekend will settle to solidly below normal next week
with periods of light W-NW flow lake effect snow.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 125 PM EST Thu Feb 6 2025
GOES Water Vapor imagery and RAP analysis show a trough pushing
through Minnesota and Ontario, with a couple shortwaves noted within
the flow. At the surface, the cold front which supported synoptic
snow earlier today has shifted through Upper Michigan, which has
left behind a mix of dry air and lake induced cloud clover and snow
showers over the forecast area. At the time of this writing, showers
were mainly present over the Keweenaw, north-central eastward toward
the front, which is supporting the tail end of synoptic snow over
Luce County. The dry air has supported clear skies in parts of the
south-central and interior west. Temperatures so far have fallen
some, but overall have been in the 20s, save for a few locations in
the west and Keweenaw which have fallen into the teens. Strong and
very strong winds have also been noted, particularly in the
Keweenaw. Highest wind report so far observed at KCMX has been
60mph. These strong winds are supporting dangerous blizzard
conditions.
For the remainder of the afternoon, cold air will continue pouring
into the region from the west, supporting more widespread lake
effect snow and continued strong to very strong winds. Highest winds
are still expected in Keweenaw, Houghton, Ontonagon, and Baraga
counties. Gusts above 50 mph will be possible to near midnight. This
will create dangerous conditions due to blowing snow, white outs,
and snow drifting. Folks should avoid travel in these locations
until conditions improve overnight. Snow accumulations in these
spots will be tough to gauge because of the wind, but another 2-4
inches should be expected. No changes are expected to the inherited
Blizzard Warnings for the Copper Country. Elsewhere, westerly winds
are expected to increase and blow 30-40 mph into the evening hours,
which will also pose a blowing snow, low visibility, and drifting
risk. Conditions should improve some overnight as the pressure
gradient decreases and cold air aloft stabilizes or warms slightly.
Expecting snow showers to ramp up in the east across Alger, Luce,
and northern Schoolcraft counties. Expecting 3-5 inches to be
possible with some isolated higher amounts.
&&
.LONG TERM /FRIDAY THROUGH THURSDAY/...
Issued at 440 PM EST Thu Feb 6 2025
Medium range models are in good agreement on the pattern evolution
across N America into the middle/end of next week. A Pacific
shortwave originating off the CA Coast will eject eastward Friday
into Saturday through the Plains states, reaching the Midwest and
Lower Great Lakes late Saturday into Saturday night, bringing some
system snow to mainly southern portions of the cwa. As this occurs,
a building ridge over the ne Pacific across AK into the Arctic will
set the stage for a deepening mid-upper level trough across much of
central and eastern Canada into the U.S. for next week. Guidance is
in excellent agreement in showing the axis of that trough extending
sw into the western U.S. For Upper MI, this amplifying pattern will
lead to colder air spilling across the northern CONUS and Upper
Great Lakes region through much of next week which will also sustain
periods of mostly light W-NW flow LES. As for temps, around normal
to blo normal temps into the weekend will be followed by prevailing
blo normal temps during much of next week. For now, extended model
guidance suggests no significant system snows are on the horizon for
Upper MI thru next week.
Beginning Friday, W to WNW winds will back toward the WSW shifting
LES northward through the day. This will LES generally being
confined to the Keweenaw and the far eastern shoreline areas of the
U.P. The LES will be diminishing through the day as well under a
moderating/drying air mass as a sfc high pres ridge gradually builds
into the area. Fri night, increased low-level convergence combined
with a subtle sfc trough will bring slight veering of winds over the
lake, shifting light LES southward again across the Keweenaw into
Keweenaw Bay and perhaps near Ontonagon. Light LES will clip areas
from around Grand Marais eastward as well.
Over the weekend, attention turns to the remnant of the mid-level
low that was off of the Pacific NW coast. That wave reaches the
Great Lakes Sat night. Models continue to show a sfc low track that
runs from OK to the Upper Ohio River Valley. With that track, the
main, heavier waa/isentropic ascent forced pcpn is focused well to
the s, but weakly coupled upper jet forcing is displaced farther n
than typical. That results in what is initially a separate area snow
moving from the Dakotas into the Great Lakes, where it eventually
merges with the pcpn associated with the low. Snow will spread into
Upper MI from w to e during the day Sat then end Sat night, but it
will be followed by light nw flow LES off of Lake Superior. Current
ensemble guidance now suggests 2 to maybe 3 inches of snowfall for
southern Menominee County with amounts trending down to an inch or
less across northern Upper MI.
During next week, conditions will be cold enough to support LES
whenever winds are onshore. Overall, the low-level winds will be
predominantly w to nw. Any passing shortwaves will give the LES a
boost, and it still looks like Mon night/Tue will be one notable
period where this will occur as a models show a vigorous Clipper
shortwave moving across the area. That wave will be followed by a
push of arctic air, but nothing out of the ordinary for this time of
year with 850 mb temps fcst around -25F. So, Tue/Wed will be the
coldest days with highs in the upper single digits to teens F. Tue
night should be the coldest night with min temps down to at least
the mid -teens F in the interior w. If high pres ends settling over
the area Tue night, traditional cold spots will slip into the -20s F.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 608 PM EST Thu Feb 6 2025
Strong pressure gradient and snow showers will create blizzard
conditions at KCMX this evening. Expect westerly winds of 40-45kts
and visibilities at or below 1/4 mile for a majority of the evening
hours with lake effect snow. Winds should decrease overnight, which
should help visibilities improve, but MVFR conditions are expected
to continue. Strong winds with snow showers also expected at
KIWD/KSAW in this period. This is expected to support primarily MVFR
conditions through the overnight period with winds of 25-30kts.
Conditions are expected to gradually improve overnight and return to
VFR by morning at SAW and stay MVFR at IWD.
&&
.MARINE...
Issued at 440 PM EST Thu Feb 6 2025
Low pres over northern Ontario just to the n of Lake Superior today
will continue the widespread west storm force winds to 50kt with the
strongest winds occurring in a corridor from w of Houghton/Ontonagon
eastward to Stannard Rock and Grand Marais into the early evening.
Winds will gradually diminish from w to e tonight with gales ending
by sunrise on Fri. Heavy freezing spray will also continue tonight
into Friday. Expect wnw winds of 20-30kt on Fri. Wind will then fall
to under 20kt for Fri night and Sat and will be under 25kt on Sun. W-
NW winds are then expected to spike up again to 25-30 kt late Monday
into Tuesday as a Clipper wave moves across the area. There is a 20-
40 pct chance for a period of gales to 35 knots late Mon night into
early Tuesday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Blizzard Warning until 1 AM EST Friday for MIZ001>004-084.
Winter Weather Advisory until 7 AM EST Friday for MIZ006-007-
085.
Lake Superior...
Gale Warning until 1 AM EST /midnight CST/ Friday for LSZ162.
Heavy Freezing Spray Warning until 7 AM EST /6 AM CST/ Friday
for LSZ162.
Storm Warning until 4 AM EST /3 AM CST/ Friday for LSZ240>242-
263.
Heavy Freezing Spray Warning until 1 PM EST /noon CST/ Friday
for LSZ240>242-263.
Storm Warning until 7 AM EST Friday for LSZ243>251-264>267.
Heavy Freezing Spray Warning until 7 PM EST Friday for
LSZ243>251-264>267.
Lake Michigan...
Gale Warning until 10 PM EST this evening for LMZ221.
Gale Warning until 4 AM EST Friday for LMZ248-250.
&&
$$
SHORT TERM...JTP
LONG TERM...Voss
AVIATION...07
MARINE...Voss
Area Forecast Discussion
National Weather Service Raleigh NC
920 PM EST Thu Feb 6 2025
.SYNOPSIS...
A cold front will push southeast through the region early Friday
morning. This front will stall to our south Friday through Saturday,
as high pressure noses in from the north. As the high pressure moves
offshore, another cold front will approach from the west Sunday.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 920 PM Thursday...
As of the 01Z surface analysis, the cool air lingers across the far
NW, north and northeast portions of cntl NC, with the surface
boundary still sagging south into the far NE Piedmont and nrn
Coastal Plain. The temperature range remains quite large, with upper
40s/around 50 degrees NE to low 60s SW.
Forecast soundings off the HRRR and RAP show a brief period of some
weak, elevated instability between 03Z and 09Z tonight, with a
stable near surface layer. The simulated reflectivity varies between
the hi-res guidance resulting in uncertainty wrt if and subsequently
how robust and how far south convection will occur. The HRRR shows
an area of showers/isolated storms (currently west of the mtns)
moving ewd across the area, generally north of US-1, between 03Z and
09Z. The 00Z HRRR shows an uptick in the convective activity from
the 18Z run. Conversely, the RAP continues to show hardly any
convection making it east of the mtns tonight. Will continue to
carry chance showers with some slight chance of thunder across the
northern half of the area through about 09Z, with highest chances
along and north of I-85. However, it is entirely possible there may
be hardly any showers at all. If the showers/storms develop, there
could be some brief, locally heavy rainfall, but they should be
moving quick enough to preclude any significant rainfall totals.
Once the main area of convection moves ewd and out of the area, some
more isolated to widely scattered showers may develop, sliding more
sewd through the area late tonight/early Fri morning as the cold
front moves in from the NW. Lows will depend on 1. the lingering sfc
boundary in the NE and its expected continued nwd drift, and 2. the
timing of the cold front form the NW late tonight. Generally expect
lows in the mid/upper 40s north to upper 50s south.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
As of 300 PM Thursday...
By Friday morning, tonight`s cold front should be aligned across the
southern tier of the forecast area. A slight chance of showers
should linger across southern counties through much of the morning,
with a brief period of dry weather as the front sags south before
another wave of low pressure moves along the front, bringing a
renewed chance of rain. The NAM/SREF are wet outliers Friday night,
and with a bit of uncertainty, have decided to increase pops from
primarily slight chance (20%) across the area to low chance (30%).
Do not think there will be any chance of thunderstorms with the
rainfall.
Temperatures will be tricky once again for Friday. While the range
of forecast temperatures for tomorrow is not as wide as the range
was yesterday for today`s temperatures, there is still a bit of
variation in the models. Noticeably, the bulk of warmer guidance in
the NBM seems to come from bias-corrected guidance, while the bulk
of cooler guidance seems to come from raw model output. With the
change in pattern as the front moves through, feel that bias-
corrected guidance is not the way to go, and will lean towards the
raw guidance. Will undercut the NBM mean, blending in the 10th and
25th percentiles, resulting in a forecast ranging from the upper 50s
near the VA/NC border to the lower 70s in the south. Considering the
cooler guidance seems to have won out for today`s forecast, think
that tomorrow`s forecast could still end up being too warm. There
will also be a wide range in Friday night`s lows, ranging from the
mid 30s to the lower 50s.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
As of 400 PM THURSDAY...
Surface high pressure centered over NJ/PA/NY on Saturday morning
will ooze down into the southern Mid-Atlantic before pushing east
and offshore in the afternoon and evening. The surface boundary will
initially be just south of central NC, before slowly lifting north
through our area in the afternoon and evening. Isentropic lift and a
weak wave of low pressure along the front will bring widespread
cloud cover and patchy light rain, with the best chance in the NE.
As the front lifts up into VA and the wave moves off the Mid-
Atlantic coast, rain chances and cloud cover should largely come to
an end from south to north on Saturday evening and Saturday night.
Total amounts are expected to be less than a tenth of an inch given
the stable conditions and absence of forcing aloft. Leaned toward
cooler guidance on Saturday with the CAD, and there will likely be a
strong temperature gradient across the area. Forecast highs range
from mid-40s in the far NE to lower-60s in the far south. Saturday
night will be very mild with lows in the 40s and 50s.
A shortwave will move across New England and the Canadian Maritimes
on Sunday as a surface low deepens off the New England. This will
drag a cold front through central NC on Sunday morning and
afternoon. A few showers can`t be ruled out with the front, but
precipitation amounts will again be light with the shortwave passing
so far to our north. POPs are only slight and confined to the south.
Thunder is not expected given such weak forcing and a lack of
instability. Skies will be partly to mostly sunny and as the cooler
air initially gets hung up west of the mountains, it will still be a
mild day with highs in the mid-60s to upper-70s.
Temperatures will drop into the mid-30s to lower-40s on Sunday night
as the cooler air finally spills south with surface high pressure
beginning to wedge down from the north. This CAD pattern will linger
from Monday all the way through Wednesday with high pressure
extending down from the north and cool NE flow resulting in overcast
skies and below-normal high temperatures. The coolest day looks to
be Monday with highs in the lower-to-mid-40s in many places, and
temperatures may even be stuck in the upper-30s near the VA border.
Tuesday`s forecast highs are also mainly in the 40s, with upper-40s
to upper-50s on Wednesday. Meanwhile precipitation chances will
increase from a combination of isentropic lift and multiple waves of
low pressure riding along the front stalled to our south. The best
chance at this time appears to be on Tuesday as a more potent
shortwave passes to our west. It doesn`t look like a washout through
the entire period from Sunday night through Tuesday, but it will be
overcast with periods of precipitation. While most ensemble members
only indicate rain during this period, a minority still indicates
potential for a rain/snow mix at times at places near the VA border,
and the deterministic 12z GFS came in a bit colder. Impacts if any
look like they would be minimal, but will still need to watch this
in the coming days. The cloudy and wet pattern will continue on
Wednesday and Thursday with yet another wave of low pressure, but
the track of this one looks to be farther west, resulting in a
warming trend and only liquid precipitation by this point. Forecast
highs by Thursday are in the mid-50s to upper-60s.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
As of 632 PM Thursday...
There is high confidence in VFR conditions to start the TAF period.
The main challenge with the 00z TAFs is the potential for SHRA/TSRA
at GSO/INT and the onset, duration, and extent of MVFR/IFR ceilings
along and ahead of a southward moving cold front. The latest
HRRR/ARW models suggest that storms upstream presently over KY and
TN may briefly impact GSO/INT between about 04 and 07z. While other
guidance is not as robust, given the kinematics and perhaps weak
instability, decided to introduce a TEMPO for TSRA. Confidence was
not high enough to include IFR with these conditions, but cannot be
ruled out, as well as some brief gusty winds. Any SHRA or TSRA
should weaken prior to reaching RDU/RWI and FAY, although a heavier
shower is possible at RDU. As the cold front approaches, areas of
IFR/MVFR ceilings will overspread the terminals, earliest at GSO/INT
and latest at FAY. Confidence is highest in IFR or lower ceilings
reaching FAY and RWI, as moisture pools along the frontal zone. Fog
may be possible but confidence is too low. If it were to occur, the
most likely terminals would be FAY/RWI. Ceilings should lift to VFR
between 10z in the northwest and 16z in the far south. Some brief
gusts to 18 kt are possible behind the front, but did not include
these in the TAF given less confidence. While LLWS was not included,
some guidance suggested a brief period of LLWS is possible.
Confidence was too low to mention, however.
Outlook: After VFR Fri aftn, sub-VFR conditions in light rain are
expected Fri night through Sat as weak high pressure noses in behind
a stalled frontal zone. VFR conditions are expected to return late
Sat night as the front weakens and dissipates, though sub-VFR
conditions are still possible into early Sun. LLWS is also possible
early Sun. Another system could bring unsettled weather Mon into Tue.
&&
.CLIMATE...
Record High Temperatures:
February 9:
KGSO: 69/1994
KRDU: 75/2023
KFAY: 75/2023
Record High Minimum Temperatures:
February 7:
KFAY: 60/1927
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Badgett
NEAR TERM...KC
SHORT TERM...Green
LONG TERM..Danco
AVIATION...Kren
CLIMATE...RAH
Area Forecast Discussion
National Weather Service Reno NV
232 PM PST Thu Feb 6 2025
.SYNOPSIS...
* Winter Storm Continues through Tomorrow: Heavy Sierra snow, strong
winds, and falling snow levels into western NV by Friday morning.
Expect difficult travel in the Sierra.
* Quieter Pattern this Weekend: Colder, drier weather with lighter
winds forecast over the weekend with chilly overnight lows.
* Storms Return Next Week: More snow may return by Tuesday, but
timing and details currently remain uncertain.
&&
.DISCUSSION...
Winter Storm Continues through Friday:
* The latest radar returns along with surface observations report
that the expected winter storm is impacting the area
particularly in the Sierra portion of the CWA. Across the area,
snow levels look to be rising as precipitation has turned from
snow in the late morning to mostly rain (with the exception of
the higher elevations) going into the afternoon. The 18Z HRRR
model run shows the wintry precipitation chances continuing
within the region (especially in the Sierra Mountains) through
the remainder today and into the beginning of tomorrow. These
chances look to taper off during the Friday afternoon hours and
be completely done for the area by Friday evening. When looking
at the latest NBM snowfall rates, the peak snowfall time frame
looks to have moved up a bit for some of the Sierra Pass areas
as both Carson Pass and Ebbetts Pass now see the potential for
up to 3 inches of snow per hour this afternoon and going into
the evening. Snow levels for the area look to rise to between
6500-7500 feet by this evening, but start to come down once
again to where they are close to the valley floor level by
Friday morning. As the bulk of the snow is still on the way,
please visit weather.gov/rev/winter for latest information on
the current winter weather products that continue along with the
latest snowfall forecast. As there have already been road
closures announced within the region, it is advised to check
CalTrans and NDOT for current road conditions if you need to
venture out especially through the Sierra passes.
* Another concern with this active weather system passing through
include enhanced winds particularly this evening going into the
morning with an associated cold front passing through the
region. The current Wind Advisory has been expanded to include
Pershing and Churchill counties and will last into Friday.
(Please see this products for more detailed information). Wind
gusts up to 55 mph are possible within the region with Sierra
Ridge wind gusts reaching up to or even exceeding the triple
digit mark. These winds look to come out of the southwest to
start and then turn more westerly by late Friday morning. It
does not look that the winds will decrease until the late
afternoon and evening hours. Will continue to monitor this, but
please prepare for these winds as they can cause with falling
snow reduced visibility and impact traveling conditions.
Quieter Pattern this Weekend:
* After the storm departs the region by Friday night, the weekend
will bring drier and calmer weather. Temperatures are still
forecast to stay on the colder side, with overnight lows dipping
into the teens in Nevada valleys and colder single-digit
temperatures in the Sierra. Winds will ease up, providing a break
from the active conditions, but the cold will be noticeable.
Please remember to prepare now as well as bundle up if you
plan to venture out this weekend.
Storms Return Next Week:
* Active winter weather could return as soon as Tuesday, bringing
more snow to the Sierra and possibly some to western Nevada. Snow
levels could vary from the valley floors to higher elevations
depending on how the storm develops. There currently looks to be
an impactful winter weather event especially for the Sierra
portion of the area again starting late Wednesday and continuing
into Thursday. However, forecasts are still uncertain, and
confidence in the exact timing and details remains low. Please
stay tuned for future forecast updates as they become available
when the system gets closer.
-Johnston/078
&&
.AVIATION...
Strong Winds Thursday night into Friday morning:
* Strong south to southwest winds at FL100 (50 to 70 kts) continue
in the area bringing turbulence and LLWS going through Friday
morning. Expect gusts over 30 to 40 kts at terminals, with periods
of gusts up to 50 kts. Rotors and wind shear near the Sierra will
create challenging flying conditions.
Heavy Sierra Snowfall/western Nevada rainfall:
* With snow levels rising going into this evening, the precipitation
type of most area terminals looks to be mostly rain with the
exception of KMMH through this evening. Periods of IFR and LIFR
conditions are expected particularly in the Sierra due to
precipitation as well as lower ceilings.
Calmer this weekend:
* VFR conditions expect to return with lighter winds and cold
mornings. Watch for FZFG at KTRK and widespread frost during the
overnight and early morning hours. Morning inversions may produce
some haze across the region as well.
-Johnston/078
&&
.AVALANCHE...
Strong winds and high elevation snow continue for the Sierra through
Friday morning.
* Snow levels: Rise up to around 7500 ft (8000 ft for the Eastern
Sierra Avalanche Center Area) this afternoon before steadily
falling overnight tonight in a north to south fashion to 5000 ft
and below.
* Snowfall totals: Expecting 2-3 feet of snow along the highest
peaks (up to 4 feet in Mono Co.) from this storm system. The
heaviest snowfall rates will take place this afternoon, with up to
3"/hr in areas covered by the Bridgeport and Eastern Sierra
Avalanche Centers. Rates will taper off this evening and then pick
back up briefly after midnight. Areas around Lake Tahoe can expect
snowfall rate of up to 1"/hr.
* SWE and SLR: The highest SWE will be along the crests (1-3", max
4"), however this system is a bit drier. SLRs start out around 8:1
but quickly rise to over 10:1 through the evening hours.
-Giralte
&&
.HYDROLOGY...
The Pit River:
* Flood Advisory remains in effect for the Pit River and tributaries
in Northwest Lassen County. The Pit River near Canby gage has
decreased about a foot from the peak on Tuesday night, but is
still near major flood stage. Downstream about 30 miles near
Bieber, flood levels are very slowly receding, but prolonged
flooding impacts to many rural roads and low lying structures will
continue. Cold temperatures and ice in slow moving and ponded
areas may exacerbate impacts and damage structures and/or block
drainage areas.
The Susan River:
* High flows continue to recede along the Susan River. Additional
rises of the river are possible with a warmer portion of the storm
this afternoon and evening. Renewed flooding is not forecast, but
can not be completely ruled out if rain/snow elevations later this
afternoon and evening are higher than expected and rainfall is
heavier than anticipated.
* Flood risk in other areas is extremely low.
-Bardsley/078
&&
.REV Watches/Warnings/Advisories...
NV...Winter Weather Advisory until noon PST Friday NVZ005.
Winter Storm Warning until noon PST Friday NVZ002.
Wind Advisory until 4 PM PST Friday NVZ001-003.
Wind Advisory from 10 PM this evening to 7 PM PST Friday NVZ004.
CA...Winter Weather Advisory until noon PST Friday CAZ070.
Winter Storm Warning until noon PST Friday CAZ071>073.
&&
$$
Area Forecast Discussion
National Weather Service Blacksburg VA
923 PM EST Thu Feb 6 2025
.SYNOPSIS...
Friday will offer a brief relief in the cloudy and rainy weather
before a series of storm systems start their way to the Mid-
Atlantic. Next week there is high confidence of multiple
opportunities for precipitation for the region but a lot of
uncertainty on the type of precipitation and their specific
impacts.
&&
.NEAR TERM /THROUGH FRIDAY/...
As of 900 PM EST Thursday...
Key Messages:
1) Flood Watch for the western CWA until 3AM.
2) Showers. Chance of thunderstorms tonight.
2) Breezy and dry Friday.
Thunderstorm complex extends from southern WV through far
western VA and into eastern TN. Rain rates of 1-2 inches an hour
are occurring with this MCS. Expect it to weaken as it crosses
the Appalachian Divide, but potential exists for flash flooding
in the meantime. Going with a short fused watch to alert folks
since ground will not hold much water due to time of year. Much
of what falls will runoff quickly.
Surface front over the forecast area remains the focus for
scattered showers and a few thunderstorms. Primary threat for
storms is across the far western CWA, along and west of I-77.
Airmass to our southwest remains unstable with CAPES of 500-1000
j/kg over the upper TN and lower OH Valley. This is promoting
formation of thunderstorms along TN/KY border...the mean wind
transporting this activity into far western VA and southern WV.
HRRR forecasts suggest activity will cross the Appalachian
divide overnight, weakening with time per loss of daytime
heating and encountering stable air east of the mountains.
Storms entering the forecast area may contain some hail and
gusty winds, but not expecting widespread hazardous weather for
our County Warning Area.
A pressure gradient over the area will tighten to provide a
chance of gusty winds of 15-30 kts, especially in elevated
areas, for the next 24 hours. Passage of the front will bring
dry air to the region Friday...afternoon highs ranging from
the 40s/50s in the mountains to the lower 60s east of the Blue
Ridge. High pressure will permit for mostly sunny skies for the
region Friday afternoon.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 130 PM EST Thursday...
Key Messages:
1) Confidence is high for unsettled weather this weekend.
2) Most of the precipitation should be rain, but wintry
precipitation is possible along the Interstate 64 corridor.
High pressure will head offshore on Friday night as clouds increase.
A low pressure system should cross the central Plains on Saturday
with the warm front extending towards the Mid Atlantic. Rain should
increase in coverage during late Friday night into Saturday morning,
but temperatures near or below freezing across the Interstate 64
corridor will promote a wintry mix of snow, sleet, and freezing
rain. As temperatures increase above freezing in this corridor, the
precipitation should change to rain. Moisture will gradually
decrease east of the Blue Ridge by Saturday night, while upslope
rain showers persist to the west as a cold front approaches.
A cold front will cross the Mid Atlantic early Sunday morning.
Northwest winds could gust up to 40 mph along the higher elevations
after the frontal passage. Upslope rain showers may linger in the
mountains through Sunday morning, and there may be a few snow
flurries in western Greenbrier County as colder air arrives. The
moisture should diminish overall on Sunday afternoon as weak high
pressure passes to the north, but this high should wedge against the
eastern slopes of the Blue Ridge during Sunday night. Another low
pressure system will develop across the southern Plains, and the
warm front should stretch towards the Mid Atlantic to bring
increasing chances of precipitation.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 130 PM EST Thursday...
Key Messages:
1) Confidence is high for more unsettled weather through the week.
2) Wintry precipitation is possible each day, but considerable
uncertainty remains on the exact details.
Zonal flow aloft will remain in place over the eastern United States
on Monday, but this flow should shift towards the southwest as an
upper level trough develops over the Rocky Mountains. Moisture will
increase again to continue an unsettled weather pattern for the
remainder of the week. The models continue to struggle with timing
and placement of a baroclinic zone setting up somewhere across the
Mid Atlantic. Complicating the picture further will be temperatures
falling towards freezing at night and rising above freezing during
the day. Wintry precipitation may be possible each day, but there
remains a considerable amount of uncertainty.
The consensus for Monday is a morning wintry mix along and north of
Route 460 that transitions to an afternoon rain, while most
locations south of Route 460 should stay liquid. The frozen
precipitation types could advance further southward on Monday night
as a stronger area of high pressure tries to wedge against the
eastern slopes of the Blue Ridge. However, the frozen precipitation
types should retreat northward later on Tuesday before diving
southward again by Tuesday night. Eventually, temperatures could
trend milder on Wednesday and Thursday as the wedge gradually erodes
to push most of the precipitation types to liquid. With such a
prolonged period featuring chances of wet weather, the threat for
flooding will also increase during the week.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
As of 745 PM EST Thursday...
Variable cloudiness is expected overnight as a cold front passes
across the region. Expecting scattered to numerous showers
during the overnight with potential for scattered thunderstorms
west of the Blue Ridge. High confidence for storms vcnty of BLF
with lower confidence for the remaining terminals. A period of
low level cloudiness is expected overnight, then clearing for
Friday, winds shifting to Northwest and increasing. All
terminals can expect wind gusts of 15 to 20 kts Friday, with
potential for LLWS vcnty of KLWB Friday morning.
.EXTENDED AVIATION OUTLOOK...
VFR conditions will be short lived. Front is expected to stall
just south of the area and remain nearly stationary through next
week. This feature will become the focus for waves of low
pressure to develop and move east along the front with several
opportunities for precipitation at all terminals. There is still
much uncertainty on the potential impacts and timing of these
storm systems in addition to precipitation types, but there is
high confidence that extended periods of sub-VFR will occur.
&&
.HYDROLOGY...
As of 900 PM EST Thursday...
Thunderstorm complex extends from southern WV through far
western VA and into eastern TN. Rain rates of 1-2 inches an hour
are occurring with this MCS. Expect it to weaken as it crosses
the Appalachian Divide, but potential exists for flash flooding
in the meantime. A flood watch is in effect for all counties
along and just west of the Appalachian Divide until 3AM Friday...
including the Greenbrier Valley of WV, far western VA, and the
NC High Country from Boone north to the VA border. The ground
this time of year promotes a high percentage of runoff.
Thunderstorm rainfall will runoff quickly!
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...Flood Watch until 3 AM EST Friday for VAZ007-009>012-015.
NC...Flood Watch until 3 AM EST Friday for NCZ001-018.
WV...Flood Watch until 3 AM EST Friday for WVZ042>044-507-508.
&&
$$
SYNOPSIS...CG
NEAR TERM...CG/PM
SHORT TERM...PW
LONG TERM...PW
AVIATION...PM
HYDROLOGY...PM