Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/14/25
Area Forecast Discussion
National Weather Service Charleston SC
846 PM EST Thu Feb 13 2025
.SYNOPSIS...
A cold front will shift offshore tonight, then stall just south
of the region on Friday. The front will lift back north as a
warm front Friday night into early Saturday. A stronger cold
front will impact the area Sunday, followed by high pressure.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
The primary cold front is now well offshore. The last bit of
rain that moved off the Georgia coast earlier has moved into
the Atlantic. Dry weather will prevail for the remainder of the
night. A secondary cold front will push south through the area
overnight as high pressure over the Mid-Mississippi Valley
builds east and bridges the central Appalachians. It will quite
a bit cooler than last night with lows dropping into the upper
30s well inland to the mid- upper 40s along the beaches.
Lake Winds: Winds will surge on Lake Moultrie overnight as a
secondary cold front pushes south of the lake. RAP soundings
show as much as 25-30 kt wind developing throughout the mixed
layer behind the front which should support at least frequent
gusts to that level. A Lake Wind Advisory has been issued from
midnight through 7 AM to account for frequent gusts >25 kt.
Incoming data support both winds and wind speeds very close to
Lake Wind Advisory criteria, but further evaluation is needed
before deciding on the need for an advisory. This will be
reevaluated with the mid- evening update.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
Friday: The mid-levels will consist of generally zonal flow
overhead. At the surface, High pressure will be centered over OH
in the morning, while a stationary front is located to our
south and southeast. The High will pass to our north during the
day, then over roughly New England overnight. As it does this,
the stationary front will transition into a warm front
overnight, then approach our area from the south. There could
even be weak troughing forming just off our coast late at night.
Weatherwise, the High will dominate our forecast during the
day, bringing dry conditions and mostly sunny skies. Gusty NE
surface winds in the morning should ease into the afternoon. But
they`ll usher colder temperatures into our area. Expect highs
in the mid to upper 50s across our SC counties, and the lower to
maybe middle 60s across our GA counties. In the evening and
overnight, as the High moves away, moisture associated with the
approaching front will overspread our area from south to north.
Most of the synoptic models and long-range CAMS hint at isolated
to maybe scattered light showers late at night, especially
across our GA counties. We have POPs no higher than chance here,
and slight chance across most of our SC counties. QPF should be
minimal. Lows will be reached around midnight, then
temperatures should moderate a few degrees overnight. Lows
should mostly be in the 40s.
Saturday: The mid-level pattern sharpens as ridging develops
over the East Coast, while troughing develops over the Central
U.S. Both will be strongest late at night, which is when we`ll
have SW flow overhead. The surface pattern will consist of High
pressure over New England, weak troughing just off our coast,
and a warm front just to our south in the morning. The High will
quickly shift away into the afternoon. As it does this, the
warm front will quickly lift north through our area, then move
away during the evening and overnight. A cold front will then
approach from the west overnight, but it`s not expected to reach
our area during this time frame. Moisture will be ushered into
our area from the Gulf, especially overnight, which is when
PWATs exceeding 1.5" should be located just to our west. Models
have a convergence line forming over our area during the day,
which would generate scattered showers. We have chance POPs
during the morning and afternoon, with QPF generally up to 0.1".
The convergence line of showers shifts north, mainly over the
Charleston Tri-County into the evening hours, and strengthens.
We have higher POPs to account for this, with another 0.1"
possible during this time period. The line shifts north of our
area after midnight, with another line approaching from the west
late. So there could be some dry slotting coming in from the
south late while chance POPs remain across our northernmost and
inland-most counties. Since we`ll be solidly in the warm
sector, temperatures will be above normal. Highs should peak in
the 70s, except cooler at the beaches. Lows will be in the upper
50s to lower 60s.
Sunday: This should be an active day. The mid-level ridge
offshore will get pushed away as the trough over the Central
U.S. in the morning moves towards the East Coast by late in the
afternoon. The surface cold front located to our west in the
morning is expected to quickly move through our area in the
afternoon. But it`s expected to bring numerous to widespread
showers to our area during the day. Up to 1" of rain is
possible. Instability remains very low, so we kept thunderstorms
out of the forecast. Southerly winds could also be quite gusty
before the front passes.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
The cold front will move through Sunday night, with High
pressure building in behind it. Dry conditions are expected on
Monday as High pressure builds in. A Low pressure system is
forecast to develop in the northern Gulf early in the week,
impacting our area midweek.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
14/00z TAF Discussion:
KCHS/KJZI/KSAV: VFR will prevail. Gusty, northernly winds will
develop after 08z with the passage of a secondary cold front.
Extended Aviation Outlook: Brief flight restrictions are
possible with showers on Saturday. A strong cold front could
bring additional flight restrictions and gusty winds on Sunday.
&&
.MARINE...
Tonight: Winds have turned west with the passage of the cold
front earlier this afternoon. Winds will turn north and
eventually northeast overnight as a secondary cold front pushes
through. Speeds will increase to 20-25 kt with gusts to 20 kt
except 15-20 kt with gusts to 25 kt in the Charleston Harbor.
Seas will build to 4-6 ft in the South Santee-Edisto Beach and
Georgia offshore legs with 3-5 ft elsewhere, except 1-2 ft in
the Charleston Harbor. Small Craft Advisories remain in effect
for all legs.
Friday: High pressure will be centered to our north in the
morning, while a stationary front is located to our south and
southeast. The High will shift over roughly New England
overnight. As it does this, the stationary front will transition
into a warm front overnight, then approach our area from the
south. There could even be weak troughing forming just off our
coast late at night. Expect strong and gusty NE winds during the
day, easing during the evening, then becoming E after midnight.
Small Craft Advisories will remain in effect for the Atlantic
waters for through the evening. Though, it may be able to expire
within 20 nm after midnight.
Saturday: High pressure will shift off New England in the
morning, while weak troughing is just off our coast, and a warm
front is just to our south. The warm front will quickly lift
north through our area during the day, then move away during the
evening and overnight. A cold front will then approach from the
west overnight. As it does, S winds will increase and become
gusty. The Small Craft Advisory for the GA waters beyond 20 nm
will persist, and new advisories will probably be needed within
20 nm overnight.
Sunday through Tuesday: S winds will surge ahead of the cold
front on Sunday, with a brief period of gale conditions
possible. Following the frontal passage Sunday evening, NW winds
will remain gusty Sunday night. Conditions should quickly
improve Monday and Tuesday.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Lake Wind Advisory until 7 AM EST Friday for SCZ045.
MARINE...Small Craft Advisory from 1 AM to 10 AM EST Friday for AMZ330.
Small Craft Advisory until 1 AM EST Saturday for AMZ350.
Small Craft Advisory from 3 AM Friday to 1 AM EST Saturday for
AMZ352-354.
Small Craft Advisory until 1 AM EST Monday for AMZ374.
&&
$$
Area Forecast Discussion
National Weather Service State College PA
653 PM EST Thu Feb 13 2025
.SYNOPSIS...
Cold and blustery conditions will cover Central Pennsylvania
tonight and Friday. Winds will gust in excess of 45 mph in some
areas through early tonight, particularly from Interstate 81
south and east. It will remain gusty on Friday as high pressure
builds into the region. Strengthening low pressure approaching
from the Ohio Valley will lift across Pennsylvania Sunday, with
another widespread wintry mix of snow, sleet, freezing rain and
rain expected Saturday into Sunday. Some of the rain may be
locally heavy as well, causing rises on smaller creeks and
streams. A blast of much colder air follows this weekend`s
storm for Monday.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Strongest push of colder air and the tightest 3 hour isallobaric
gradient over the eastern zones this evening prompted us to
hoist a Wind Advisory for the counties containing Interstate 81
and points to the SE where peak gusts of 45-50 kts have been
noted over the past few hours.
Elsewhere, the approach of a well defined jet entrance region
and moist, westerly upslope flow was generating widespread snow
showers and slick roads across the Western Mtns of PA where a
SPS was issued for snow accums of 1-2 inches through 05Z Friday.
For the majority of the Central Ridge and Valley region, Susq
Valley and Ncent Mtns Gusty west winds of 25 to 30 kts and ocnl
3-5SM with a light coating of snow is expected.
Low temps tonight will vary from 10-15F across the NW Mtns and
Laurel Highlands to the upper teens and low 20s elsewhere.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
Blustery conditions continue Friday with temperatures struggling
to exceed freezing over the northern 2/3 of central PA, all
thanks to 1035+mb area of high pressure moving over the region.
Mixing down model 900mb temps of around -10C supports Maxtemps
ranging from the 20s over the Alleghenies, to the mid 30s in the
Lower Susq Valley. Fair weather and light wind should last into
Friday night associated with the retreating high pressure.
However, model RH profiles indicate thickening high clouds ahead
of a warm front entering the Ohio Valley, which should keep
temps from falling too far.
Eyes quickly turn to the next in the seemingly endless train of
systems, slated to arrive late Friday night and Saturday. Latest
guidance is persistent in phasing a southern stream shortwave
with the northern branch over the Midwest this weekend, with low
pressure lifting northeastward out of the Miss Valley Sat
night, then across PA on Sunday. This low track, along with
lack of a blocking high to the northeast, will make for another
messy storm system, with snow breaking out across central and
northern PA by Saturday morning, with rain or freezing rain to
start across the south. Transition to sleet and freezing rain
again is expected by Saturday afternoon and to plain rain late
Saturday night into Sunday morning. Heaviest precipitation with
this system falls as plain rain ahead of the cold front on
Sunday.
EPS prob charts still indicate most likely snow totals by Sat
night ranging from <1 inch over Southern PA, to 2-3 inches over
the N Mtns. Model soundings still indicate potential for a
period of fzra Sat and Sat night, with a tenth of an inch or
more being possible across central and northern areas on top of
a few inches of snow. Ensemble mean rainfall of near 1 inch
will likely be insufficient to cause significant flooding (even
with snowmelt) based on latest headwater guidance.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Steady pcpn with weekend system will be or should have
transitioned to lingering snow showers, mainly over the NW
mountains and Laurel Highlands.
There is a high degree of certainty in blustery and cold
conditions arriving Sunday night into Monday, with strong
gradient winds behind the surface low. Very cold, and
expectedly dry weather, extends into mid week with widespread
single digit minimum temps as Arctic high pressure builds across
the northeast/Mid Atlantic.
The next weather wrinkle is a surface low forecast to move from
the Gulf coast Wednesday to the Carolina coast Thursday
morning. This could produce snow over parts of PA starting next
Wednesday and continuing into Thursday, well to the north of
system.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
Restrictions across the western airspace (BFD/JST/AOO) with VFR
prevailing at UNV/IPT/MDT/LNS as of 00Z observations as
scattered snow showers across the western half of the airspace
will continue for throughout the next couple of hours. Model
guidance is not the most well-resolved with regards to timing
and coverage of snow showers in the near-term (through 06Z
Friday), thus have used a combination of GLAMP/RAP model
guidance with some adjustments based on current radar. The
highest confidence for a longer period of IFR conditions will be
at JST/BFD/AOO (~50-60%) confidence with lower confidence
(~40%) at UNV. Current radar trends; however, do outline light
returns near UNV as of 00Z Friday, thus have outlined MVFR
ceilings in the near-term with a TEMPO group given radar
trends/RAP RH cross-sections. Signals for a brief period of LIFR
at JST is noted in GLAMP guidance between 06-08Z Friday;
however, RAP model cross-sections are not as keen on development
of low ceilings/visibilities in this timeframe. Given this
discrepancy, have outlined a TEMPO for the best timing of
further restrictions, but trended toward low-end IFR instead of
prevailing LIFR.
Concerns further east are mainly in the form of gusty westerly
(290-320) winds that are expected to continue through 06Z Friday
with high (~80-90%) confidence. There is moderate-to-high
confidence on gusts dipping below 35kts at MDT/LNS/IPT after
06Z, with HREF probabilities < 20% at these airfields. Gusts are
expected to increase across the Allegheny Front (JST/AOO,
lesser UNV) in the 06-12Z timeframe; however, the bulk of wind
gusts will be confined to higher terrain locations. High (> 90%)
confidence in gusts dipping below 35kts ~16Z Friday with the
influence of high pressure on the region. LLWS concerns at the
airfields are minimal throughout the entire TAF package with any
impacts limited to AOO/JST; however, confidence remains too low
(~20-30%) to include in the 00Z TAF package.
All airfields outside of BFD/JST are expected to prevail VFR
prior to 12Z Friday with moderate (~70%) confidence. After
sunrise, improvement is expected at BFD/JST with high (80-90%)
confidence in both airfields reaching VFR thresholds by 16Z
given modest model agreement in this timeframe. A combination of
HREF/RAP model guidance does indicate lower ceilings hanging on
slightly longer at BFD; however, generally expected to resolve
around the same time as JST, with alternative scenarios holding
on to MVFR conditions for an additional 1-2 hours.
Outlook...
Sat...Rain/snow/low cigs possible, mainly PM.
Sun...AM rain/low cigs likely, snow possible NW Mtns. Becoming
windy toward evening with snow showers W Mtns.
Mon...Post cold front. Sub VFR cigs and SHSN BFD/JST. Gusty
northwest winds.
Tue...Generally VFR and breezy. Isold SHSn vicinity BFD.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 10 PM EST this evening for PAZ036-056>059-
063>066.
&&
$$
SYNOPSIS...DeVoir/Fitzgerald
NEAR TERM...DeVoir/Fitzgerald
SHORT TERM...DeVoir/Fitzgerald
LONG TERM...DeVoir/Gartner
AVIATION...NPB
Area Forecast Discussion
National Weather Service Des Moines IA
535 PM CST Thu Feb 13 2025
...Updated for the 00z Aviation Discussion...
.KEY MESSAGES...
- Blowing snow affecting particularly east/west road expected on
midday Friday into the afternoon.
- Brief period of moderate to possibly heavy snow passing
southwest to northeast over central into northeast Iowa Friday
afternoon.
- Additional snow (50-60%) with light to moderate accumulations
on late Friday night into Saturday.
- Very cold air sets in for Sunday through next week with cold
weather headlines likely during this time.
&&
.DISCUSSION...
Issued at 337 PM CST Thu Feb 13 2025
Active pattern remains in place through the weekend with a few
different systems impacting the state. Currently, quiet conditions
with surface ridging overhead along with ample sunshine. Despite
excellent insolation today, the fresh snow cover has hampered
temperatures with reading struggling to get out of the single digits
over much of central Iowa. With the ridge passing, winds become
southerly by tonight as warm advection begins to intensify. The
gradual strengthening of south winds overnight along with increasing
clouds should support temperatures with readings becoming steady if
not slowly rising during the early morning hours.
The strong warm advection persists into Friday with 50kts+ southwest
flow at 850mb. This is eventually reflected at the surface with an
increasing pressure gradient as steady surface winds of 15 to 25 mph
are expected by midday with gusts of 35 to possibly 40 mph. Given
the fresh snowpack, blowing snow is likely in rural areas by late
morning through the entire afternoon. Impacts are likely to be most
problematic on east/west roads with the wind generally orthogonal to
the strong flow. Crawlers and small drifts are likely to develop
and may produce slick areas on roads through the afternoon.
Meanwhile, robust theta-e advection is anticipated as moisture
streams northward on the fast low level flow. Strong isentropic lift
rapidly lowers condensation pressure deficits with precipitation
developing to the southwest of the area by late morning but
advecting quickly into the forecast area given the strong mean winds
aloft. The snow is expected to expand in coverage as it progresses
northeast through the afternoon with a brief hour or two of moderate
to potentially heavy snowfall before ending. The combination of the
snow and blowing snow are likely to produce brief significant
impacts for the afternoon/early evening commute on Friday,
particularly across the northeast third of the forecast area and
headlines may need to be considered during this time.
The bulk of forcing races northeast of the forecast area by Friday
evening along with much of the precipitation. At this point,
confidence in the forecast becomes lower as there is a separation in
guidance. GFS/HRRR and RAP intensify mid level kinematic forcing
across eastern Nebraska into western Iowa Friday night with
precipitation expanding after midnight. Cross sections indicate weak
static stability over much of central into southern Iowa during this
time with the potential for banding to set up by Saturday morning.
While snowfall amounts during this time remain somewhat limited, if
banding does occur, then a narrow but more intense band of snow is
possible over the forecast area during this time. Current guidance
would suggest something from near Atlantic to Ames and Waterloo but
this may continue to adjust with subsequent runs. Farther south,
some mixed precipitation is possible in far southern Iowa where a
warm layer exists with precipitation onset. Eventually, cooler air
wins out with all precipitation becoming snow. The other solutions
from the NAM and Euro are much less dramatic keeping the bulk of
precipitation from this round of forcing mainly south of Iowa. There
still remains plenty of time to refine the overall potential in the
next couple of forecast cycles.
Thereafter, arctic air pushes back into Iowa and remains into much
of next week. Lingering light snow/flurries are anticipated into
Saturday night with another weak wave in the northwest flow along
with a decent chunk of soundings within the dendritic layer making
flurry/light snow production rather easy. Another system arrives by
Monday afternoon with some light snow production in the southwest
third of Iowa although recent model trends have shifted the heavier
snowfall farther southwest into Kansas and Missouri. Otherwise,
temperatures will be well below normal with headlines for the cold
likely at various times through the week.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 535 PM CST Thu Feb 13 2025
VFR conditions persist through much of the upcoming TAF period.
South winds increase quickly on Friday morning with gusts of
20-25+ kts anticipated. This will result in some blowing of the
existing snowpack on the ground. A short burst of snow is
expected in the afternoon, between 18-00z, moving quickly west
to east across Iowa. This will bring MVFR to pockets of IFR
reductions as ceilings come down and visibility briefly drops in
the falling and blowing snow.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Cogil
AVIATION...Hagenhoff
Area Forecast Discussion
National Weather Service Goodland KS
345 PM MST Thu Feb 13 2025
.KEY MESSAGES...
- An Arctic airmass will surge southward into the Central Plains
Friday night into Saturday. A short period of snow is possible
Friday evening through Saturday morning. Wind chill readings
ranging from 5 to 15 degrees below zero are expected Saturday
evening through Sunday morning.
- Another Arctic airmass will surge southward into the Central
Plains early next week and persist through at least mid week.
Dangerously cold wind chill readings are possible on Tuesday
and Wednesday. Light to moderate snow will be possible Monday
night and Tuesday.
&&
.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 130 PM MST Thu Feb 13 2025
Shortwave ridging today will give way to southwest flow tomorrow
ahead of an approaching trough. Temperatures will drop rapidly
after sunset again tonight with mostly clear skies through this
evening. Increasing winds and clouds overnight will limit
radiational cooling and tend to keep temperatures steady or
slowly rising. Expecting lows mainly in the teens, with some
single digits above zero possible from McCook to Norton where
winds will be lightest. Tomorrow, skies will be mostly cloudy
with breezy to windy southwest winds south of Interstate 70.
Temperatures will try to moderate but with the clouds and snow
pack not sure they will get as warm as the models say. Highs
will range from the low 40s northeast (McCook) to around 60
southwest (Tribune), but with only medium confidence. As the
shortwave trough moves out of the Rockies Friday night,
expecting scattered rain showers early, changing to snow showers
as colder air moves in behind the accompanying surface front.
HRRR shows some low MUCAPE available ahead of the front with
decent reflectivities and some lightning, so added an isolated
thunder mention through 04z. Precipitation will be all snow
after 06z with accumulations less than 1". Low temperatures will
be mainly in the teens. Lingering snow showers into Saturday
morning will produce less than a half inch of additional
accumulation. Skies continue cloudy through the day with highs
in the 20s. Southwest areas may see a little additional light
snow Saturday evening with secondary shortwave/showers moving
off the Palmer Divide. Clearing skies and light winds will allow
temperatures to drop into the single digits Saturday night with
wind chills to around 10 below. Subtle ridging aloft on Sunday
will result in mostly sunny skies on Sunday but cold, with
highs ranging from the lower 20s in eastern areas (McCook to
Hill City) to the lower 30s in Colorado. Lows Sunday night will
be in the teens.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
Issued at 130 PM MST Thu Feb 13 2025
Temperatures will briefly moderate on Monday with the zonal flow
aloft persisting one more day. Highs will range from the mid 20s
in the northeast (McCook to Norton) to the mid 40s in the
southwest (Tribune and Leoti). Temperatures plunge again Monday
night with another Arctic blast. They will fall into the single
digits above/below zero with wind chills 15 to 20 below by
Tuesday morning. Highs on Tuesday will only manage the single
digits and teens, then falling in the single digits below zero
Tuesday night and wind chills to 20 below. Light snow will
likely accompany the Arctic air Monday night and Tuesday with a
shortwave trough rotating in from the northern plains. Snow
totals currently running in the 3-6" range with 40-50%
probabilities, with some low probabilities (20%) for greater
than 6". May see something similar to this last event with the
very cold temperatures promoting high snow-liquid ratios. Winds
do not look to be an issue. Current timing shows snow ending
Tuesday night. If skies clear soon enough temperatures could
drop well into the teens below zero with wind chills 20 to 30
below. Models diverge a bit for Wednesday and Thursday, with
some showing another shortwave trough and chance for light snow,
others showing shortwave ridging and dry conditions. Either
way, it will continue to be cold with the Arctic air mass slow
to move out.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 345 PM MST Thu Feb 13 2025
KGLD...VFR conditions are expected through the period. A
southerly wind gusting to 20kts at taf issuance will increase
with gusts to 30kts overnight. Winds continue to veer to the
southwest, gusting up to 25kts from 18z-22z then veer further to
the west at speeds up to 10kts after 23z.
KMCK...VFR conditions are expected through the period. A
southerly wind around 10kts at taf issuance will continue
through the night, slightly backing to the southeast at similar
speeds from 12z-17z. After 18z, winds then veer to the south at
speeds around 10kts.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.
&&
$$
SHORT TERM...024
LONG TERM...024
AVIATION...99
Area Forecast Discussion
National Weather Service Green Bay WI
510 PM CST Thu Feb 13 2025
Updated aviation portion for 00Z TAF issuance
.KEY MESSAGES...
- Very cold temperatures are expected tonight, with lows in the
single digits to teens below zero. Wind chills may briefly drop
between 15 and 30 degrees below zero early Friday morning.
- There is a 50-80% chance for greater than 4 inches of snow late
Friday afternoon through Friday night. Hazardous travel is
expected across the area. Very difficult travel is possible on
Friday evening due to heavy snow and low visibilities.
- Bitterly cold wind chills are expected to return for the early
to mid part of next week. Coldest readings are expected to occur
Monday morning, with wind chills dropping between 20 and 35
degrees below zero.
&&
.DISCUSSION...
Issued at 234 PM CST Thu Feb 13 2025
Short Term...Tonight and Friday
The latest RAP analysis and satellite/radar imagery show high
pressure centered across the central Great Plains with a ridge
axis extending northward across Minnesota. While scattered lake
clouds and flurries continue along the Upper Peninsula border,
the rest of the region observed clearing skies this morning,
leading to widespread sunshine early this afternoon. As good
radiational cooling conditions develop tonight, forecast concerns
start out with low temperatures tonight, followed by potential
snowfall amounts for Friday night.
Temperatures Tonight: The surface ridge axis will move across the
region. Gusty winds this afternoon will diminish this evening
before becoming light and variable overnight. While there are
scattered mid-clouds over North Dakota, they appear relatively
thin and not widespread enough to have much influence on temps.
Therefore expect temps to be on the cold side of guidance as deep,
fresh snowpack should augment the good radiational cooling
conditions. Wind chills may approach Cold Weather Criteria over
the northwoods at times, but with winds decoupling, don`t think
wind chills will remain below criteria for a significant length
of time. Lows to range from near 0 close to Lake Michigan to 20
below over north-central WI.
Snowfall Friday Afternoon through Friday Night: After a sunny
start to the day, clouds will be on the increase through the day.
Moderately strong warm advection within a coupled jet structure
should then lead to a swath of snow blossoming from late morning
through the afternoon over the northern Mississippi Valley. Timing
based on latest guidance shows snow arriving over north-central WI
in the 4-6 pm hour, though there are indications of a narrow fgen
band developing earlier in the afternoon. The snow should then
quickly advance into the Fox Valley during the 5-7 pm hour. The
heaviest snow rates of 1" per hour should start within 1-2 hours
after the onset of the snow and last for 2-3 hours at most
locations.
Two of the more challenging aspects to this storm revolve around
snow to liquid ratios and potential for lake banding. Signals
continue to appear for a 200-300mb deep DGZ during the strong
lift period in the evening. Because the snow event last weekend
featured snow ratios 20-40 to 1 at times, think we could see these
sort of high end snow ratios when the peak lift occurs in the
evening. This will be more widespread over central and east-
central WI than over the far north where the max lift is above the
dendritic growth zone.
Some CAMS also indicate the potential for a lake band to develop
late Friday night over the Door Peninsula. This band could easily
push Door County above 6" should it develop. But considering the
low level shear, think banding should be more diffuse that those
CAMS indicate and will stay the course.
The prevailing thought across northern Mississippi/western Great
Lakes offices was to issue a high end Winter Weather Advisory for
this event. Uncertainty with the factors above could lead to
Winter Storm Warnings issued in later shifts if confidence
increases. Instead, will issue a Winter Weather Advisory for late
Friday afternoon through Friday night. This Advisory may need to
get extended through Saturday if confidence increases for several
more inches of snow over northeast WI.
Long Term...Friday Night Through Thursday
Focus for the extended remains front-loaded on snowfall potential
late Friday night into early Saturday morning as low pressure
departs to the northeast. Attention then quickly shifts to the
return of dangerous cold later this weekend, lasting through at
least the middle of next week.
Saturday morning snowfall potential... As the surface low tracks
into the Ohio Valley Friday night, biggest question will be
whether or not potential exists for a secondary round of
synoptically-driven snow Saturday morning. As 700 mb PV anomaly
and coupled jet max traverse the Great Lakes Saturday morning,
medium-range models pick up on a deformation zone developing on
the northwest quadrant of the surface low over southern Wisconsin.
Though not as strong as Friday evening, pockets of FGEN paired
with sufficient lift within the DGZ (~8 to 10k ft deep at this
time) would support additional bursts of moderate to heavy snow
across our southern two tiers of counties early Saturday
morning. Additionally, CAMs suggest the possibility for lake
enhancement over the Door peninsula early Saturday morning as a
35 to 40 knot LLJ noses a swath of higher QPF into east-central
Wisconsin and surface winds back to south/southeasterly. Where the
convergence band sets up remains uncertain, although this would be
a scenario in which the lakeshore counties could pick up another
few inches of snow into Saturday afternoon, nudging snowfall
totals into warning territory for some.
Dangerous cold late this week/early next week... Arctic high
slides across the US/Canada border late this weekend, bringing
first percentile 850 mb temperatures to the upper Mississippi
Valley early Monday morning. Result will be highs dipping into
the single digits area-wide Monday and Tuesday, with wind chills
taking between 20 and 35 degrees below zero. Confidence continues
to increase regarding the necessity for cold weather headlines
early Monday and Tuesday mornings, possibly into Wednesday morning.
Will continue to monitor given the tight margin currently in the
forecast between advisory and warning thresholds.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 510 PM CST Thu Feb 13 2025
Good flying weather is expected through early Friday afternoon with
VFR conditions. Widely scattered mid and high clouds will pass
over the region tonight before overcast conditions above 10000 ft
arrive on Friday morning. Conditions are expected to deteriorate
rapidly as moderate to heavy snow arrives late Friday afternoon
into early Friday evening.
Light winds are expected through Friday morning, with gusty
southerly winds to around 15 knots expected Friday afternoon.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 4 PM Friday to 6 AM CST Saturday
for WIZ005-010-018-030-035-036-045.
Winter Weather Advisory from 6 PM Friday to 6 AM CST Saturday
for WIZ011>013-019>021-031-037>040-048>050-073-074.
Winter Weather Advisory from 8 PM Friday to 9 AM CST Saturday
for WIZ022.
&&
$$
DISCUSSION.....MPC/Goodin
AVIATION.......Kurimski
Area Forecast Discussion
National Weather Service Gray ME
1015 PM EST Thu Feb 13 2025
.SYNOPSIS...
Slippery roadways remain possible over portions of the region
through this evening. Winds pick up late this evening and
Friday behind the exiting low and then diminish Friday night as
high pressure moves into the region, allowing for dry weather
through the first part of Saturday. A more potent winter storm
is becoming more likely over the upcoming weekend.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
03Z Update...
Have held onto the raised pops for a few more hours as snow
showers transition across portions of the region. Some of the
echoes were not reaching the ground late this evening however.
Made minor adjustments to the near term portion of the forecast
for temperatures, dew points and winds. Highest wind gusts this
evening will continue over southern New Hampshire and the
mountains and foothills of Maine/northern New Hampshire where
wind advisories remain in place.
01Z Update...
Update this evening is to raise pops across much of the region.
The latest HRRR has some of the snow showers exiting the
mountains surviving the trip to the coastline late this evening.
Light accumulations of snow are possible with this batch of
precip.
Update...
Have allowed the remainder of the Winter Weather Advisories to
expire this evening. Otherwise, any additional snowfall shifts
to upslope regions of the northern mountains. May need to up
pops across the higher terrain with webcams showing steady snow
in the north. Otherwise, only minor tweaks to the near term
portion of the forecast. Will remove any mention of mixed
precipitation as ptypes at this point will switch to all snow if
it hasn`t already. Gears now shift towards the very windy
conditions tonight into Friday with the potential for heavy snow
and mixed precipitation over the weekend.
Prev Disc...
Precipitation will continue tapering off from southwest to
northeast through this afternoon and evening. Expecting mostly
light snow across northern areas with more of a mix possible to
the south. Then drying aloft and moist low- levels will allow
for the potential of drizzle or freezing drizzle thereafter, and
latest radar imagery is showing evidence of this drying quickly
moving in from the west and southwest. Even with the downward
trend in precip, portions of the Winter Weather Advisory that
had been scheduled to drop at 3PM have been extended through the
evening commute from the Maine Midcoast and interior, where the
cold air dam has kept temps below freezing or even well below
in some places as it doesn`t take much in the way of freezing
precip to create slick roads. Even in areas where air temps are
above freezing and not in Winter Weather Advisories, pavement
could still stay cold enough in some places to be slick during
the evening commute. Not expecting much in the way of additional
precip south of the mountains beyond 6 to 7PM or so, but the
mountains will switch to upslope snow showers through tonight.
Going into this evening, winds quickly ramp up as the low pressure
departs with rapid pressure rises trailing behind. Wind gusts of 30
to 40 mph are possible across most of the area and to around 45 mph
across southern NH, where the Wind Advisory is in effect this
evening. Even stronger gusts are expected in the mountains. Cold air
advection will steadily drop temperatures into the single to digits
to teens, and it`s possible wet roadways could refreeze. The gusty
winds will make it feel much colder with wind chills a few degrees
below zero possible south of the mountains and closer to -10 degrees
in the mountains.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Strong cold air advection will continue on Friday with low
pressure lifting into the Canadian Maritimes and high pressure
starting to build in from the west. It will feel quite blustery
out due to very windy conditions and temperatures staying in the
20s south of the mountains and teens in the mountains. Forecast
soundings support gusts of as high as 45 to 50 mph with good
mixing bring those higher winds down from aloft, so the
inherited Wind Advisory over much of the area looks good.
Southern NH may end up needing one, but since there`s already
one in effect there this evening, have left that alone for now.
These gusty winds winds will make it feel about 10-15 degrees
colder than the air temps.
In the mountains, upslope snow showers will likely continue, and
with high Froude numbers, have increased PoPs downwind to at least
include a slight chance, except a little higher in the mountains,
but the limiting factor downwind of the mountains may be the amount
of low-level moisture.
The gradient relaxes Friday evening into Friday night as high
pressure further builds into New England, allowing winds to
gradually ease. However, there will still be a still factor,
especially in the mountains where winds won`t slacken as much. Wind
chills in the positive to negative single digits are possible across
southern areas while the mountains hold on to wind chills in the
negative double digits.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Late Evening Update...
After our strong gusty winds on Friday, the focus shifts
towards a winter storm expected over the weekend. Latest
operational models and ensemble solutions suggest a wintry mix
will be in play after steady snowfall Saturday night as the
system tracks along a coastal front. Atmospheric profiles
suggest warm air arrives aloft to allow for snow to changes to
sleet and freezing rain over southern and central areas during
the day Sunday. The combination of heavy wet snow and ice
buildup on the trees may lead to downed limbs and powerlines
Sunday and particularly into Monday as strong gusty winds
develop with the intensifying and departing area of low
pressure.
Thereafter, mainly dry conditions and windy weather through
midweek. Upslope snow showers can be expected once again. The
next system will approach late on Thursday, potentially from off
the Eastern Seaboard.
Prev Disc...
Overview: High pressure pushes north Saturday as large low
pressure moves into the Ohio Valley. This low continues north,
reorganizing off the New England coast into Sunday. Significant
amounts of wintry precipitation are forecast beginning Saturday
evening and lasting into early Sunday night. The low departs
Monday, with strong west winds in its wake.
Details: Main focus is on the continued trend for an impactful
significant winter storm this weekend. Maine headlines remain:
-Significant amounts of wintry precipitation with liquid
equivalent of around 1 inch for much of the forecast area.
-Accumulating snow to begin the event Sat night into Sun morning,
with a transition to sleet/freezing rain along a belt from the
higher terrain to the coast Sunday. There is uncertainty in
positioning of this wintry mix, as well as duration/amounts of sleet
of freezing rain. Details below.
-Strong west winds wrap around the departing low into early next
week.
High pressure will drift NE Saturday with precipitation slowly
pushing into southern NH during the late afternoon. This continues
to overspread the area as the evening progresses, with increasing
intensity. Snow ratios are fluffy to begin with, but isothermal
profile warms just above good snow growth zone to tamp down ratios
as precip continues to invade. Continued warming aloft has been
evident, and continues to be a factor into Sunday morning. This
comes as the inland low begins to consolidate to a coastal low off
the southern New England coast through Sunday. How quickly this
transition occurs will play a role in how entrenched cold air gets
at the surface. Current forecast supports NE to N winds for much of
the event, resulting in plenty of cold air at the surface...but
still some warming around 800mb. This is why confidence continues to
be higher for wintry precip through the event, but uncertain at
precip types. Warming aloft is shallow enough to support a broader
swath of sleet or ice pellets at this time, with snow to the north
Sunday. Do think there will be a corridor of freezing rain mixing
with this, or pure freezing rain, coast-side of the inland sleet
corridor. Regardless, NBM probability of > 1" of QPF is high for
much of the CWA. This much liquid equivalent in wintry precipitation
will lead to travel impacts on both ends of Sunday.
The strong low will finally pull north overnight into Monday
morning. Strong pressure gradient then drapes over the CWA through
Tuesday, resulting in strong west surface winds. These may match
similar readings to Friday, but will see how long the gradient
holds. Otherwise, the extended looks drier, a welcome break from the
busy weather late this week and the weekend. Temps also remain cool,
with highs in the 20s with teens to the north. Overnight lows fall
into the single digits.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Short Term...Scattered snow showers are expected through late
this evening before conditions improve overnight as ceilings
lift and precipitation ends from south to north, but AUG and RKD
will probably be the last to reach VFR. Mainly VFR Friday through
Friday night, except HIE could see snow showers and MVFR
ceilings from time to time tonight through Friday. Can`t rule
out a couple of snow showers and brief restrictions elsewhere,
but coverage/chances look low enough to leave out of the TAFs.
Winds then become a concern this evening through Friday with
gusts of 30-35 kt, possibly 40-45 kt on occasion.
Long Term...VFR Saturday will see clouds thicken and lower as
the afternoon progresses. MVFR to IFR ceilings spread in by
Sunday morning with SN increasing in coverage overnight. A
corridor of PL and FZRN is also expected, but uncertain on
timing and location for now. These conditions continue through
Sunday, with improvement overnight into Monday. N winds become W
Monday, again becoming gusty with winds up to 30 or 35 kt
possible into Tuesday.
&&
.MARINE...
Short Term...W/WNW winds rapidly increase over the waters tonight
with gales continuing through Friday. A few gusts to storms may
also occur over the outer waters on Friday. Winds gradually
subside Friday night, but an SCA will likely be needed once the
gales come to an end.
Long Term...High pressure Saturday will give way to incoming low
pressure overnight through Sunday. This low will initially be
inland as it tracks north, but consolidate near Cape Cod before
tracking into the Gulf of Maine Sunday. This will bring a period
of SCA to Gale conditions Sunday. As the low exits, winds shift
W into Monday, with a longer period of at least Gale conditions
through Tuesday.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Wind Advisory until 7 PM EST Friday for MEZ007>009-012>014.
Wind Advisory from 10 AM to 7 PM EST Friday for MEZ018>028-033.
NH...Wind Advisory until 7 PM EST Friday for NHZ001>006.
Wind Advisory until midnight EST tonight for NHZ007>015.
MARINE...Gale Warning until midnight EST Friday night for ANZ150>152.
Gale Warning until 9 PM EST Friday for ANZ153-154.
&&
$$
Cannon
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
614 PM CST Thu Feb 13 2025
.KEY MESSAGES...
- We are still in line for a snowy end to Valentine`s Day,
though uncertainty remains higher than normal with snow totals
this close to the onset of an event.
- Brief break from the dangerous cold Friday and Saturday, but
additional Extreme Cold headlines likely Saturday night
through Thursday morning.
&&
.DISCUSSION...
Issued at 324 PM CST Thu Feb 13 2025
It`s a classic deceiving winter day across the area. The skies are
bright and sunny and the winds are light, so your eyes are telling
you it`s time to break out the shorts, but reality ends up being a
cold pill to swallow with temperatures not far above zero. Winds are
already out of some form of a southerly direction as WAA is
beginning ahead of an expansive trough coming onshore the west coast
of the CONUS.
Friday through Saturday. That trough out west now will work across
the central CONUS and will be the source for our potential
Valentine`s Day Dust-up. Model spread with forecast snowfall amounts
remains higher than what we would normally expect as we get to 24
hours out from the snow falling. We`ll jump first into the sources
of uncertainty. The biggest issue we`ll be dealing with is the
antecedent airmass. It`s arctic, it`s cold, and it`s dry. So there`s
quite a bit of spread in the models with just how quickly the
atmosphere saturates to allow snow to fall. So far the models have
tended to be too aggressive with overcoming the dry this winter, so
the forecast we have today continues to favor the drier models, such
as the Canadian and Euro, and away from the more aggressive models
such as the NAM and especially the 13.12 GFS. The other bit of
uncertainty comes with the sources of forcing. There are two of
those. The strongest forcing will be a zone of strong isentropic
ascent being driven by h85 winds in excess of 50 kts coming out of
the Plains and into southern MN and western WI Friday afternoon. To
the northwest of this along a cold front will be a broad zone of
fgen induced lift that will likely produce a broad area of lighter
snow than what we see with the WAA band. That WAA will be getting
going on top of the MPX area Friday afternoon and move across
western WI during the evening, while that FGEN band will going going
late Friday morning/early Friday afternoon over central MN, then
slowly sag southeast across the MPX area through the course of
Friday night and linger down in south central and southeast MN
through Saturday morning. For the WAA, the main question is when
does the snow get going (if it were the summer, we would be asking
when will the cap break!), while for the fgen band it`s a question
of how much moisture will be available for it.
Possible scenarios. We`ll start with the boom. That comes down to
that WAA band going gangbusters by the early afternoon. This is the
forcing that will have the potential to produce 1+ inch per hour
snow rates and could easily lay down 3-5" of snow in the course of 4-
6 hours. This would then be followed up by the prolonged light fgen
snow Friday night that would likely bring an additional 1-2" of
snow. This is what the 13.12 GFS went with. The most likely
locations to cash in like this on both forcing sources are out there
by Ladysmith and Eau Claire, but it could happen as far west as the
Twin Cities. Now for the bust scenario and that is that the WAA
forcing doesn`t have enough residence time to saturate the
atmosphere and is already east of the MPX area before it gets going.
If that happens, then all we are left with is the prolonged light
fgen forced snow Friday night, with snow totals generally in the 1-
3" range. The 13.18 HRRR is probably the best example of this bust
scenario.
Headline decision. Given the spread, this wasn`t an easy task, but
we went with a Winter Weather Advisory for all of our WI counties
with the exception of Polk county. This coincides with areas where
we currently have 3-6" of snow in the forecast. In addition, this is
where our probabilistic snowfall guidance has probabilities of
exceeding 4" of snow at or above 50%. Given the timing of the
snowfall with respect to the Friday evening rush, we strongly
considered taking the advisory back across the Twin Cities, but with
the potential for the Twin Cities to get missed by the WAA forcing,
which would result in little snow and impact to the evening commute,
we kept the Twin Cities headline free for now. Depending on how much
moisture lingers on the cold front going into Saturday morning, we
may also need to issue a Winter Weather Advisory across the south
central MN as well, though we have time to make that decision.
For the rest of the forecast, it will be cold as the lobe of arctic
air currently over western Hudson Bay sags south into the northern
CONUS for the first half of next week. For Sunday through Wednesday,
highs will struggle to get above zero, with lows in the teens and
20s below zero. The one saving grace in all of this is that with
high pressure over the northern CONUS, the winds will remain
relatively light next week so that apparent temperatures don`t look
to spend much time colder than 40 below zero, but they will be cold
enough so that we will likely need at least Cold Weather Advisories
during the overnight and morning hours from Saturday night through
Thursday morning. Beyond this forecast, milder airmasses still loom
for next weekend into the week of the 24th.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 529 PM CST Thu Feb 13 2025
Mostly clear skies and light winds prevail until a layer of high
level clouds begin to move in from west to east tomorrow
morning. Winds will turn light and variable overnight, but
generally out of the S/SE. Wind speeds will increase to 10-15
knots by Friday afternoon. A few gusts in the 20 to 25 knot
range will be possible late Friday afternoon.
Snow is expected to develop across central MN as early Friday
afternoon. There is a good amount of uncertainty when we
saturate and see snow occur and where this occurs will be key.
If we saturate earlier, higher snow amounts are likely and lower
visibilities too. Prob30s with lower vsbys were added to to
address the uncertainty. Light snow should continue through the
end of the TAF period with cigs reaching MVFR to possibly IFR
levels.
KMSP... Winds will gradually turn more SSE by sunrise Friday. A
mid to high level cloud deck will move in Friday morning before
snow and lower cigs Friday afternoon. Snow will develop overhead
adding to the uncertainty. A burst of heavier snow is possible
between 22z-01z and a Prob30 was included to address the
uncertainty. Light snow should linger through much of Friday
night and the Taf period.
/OUTLOOK FOR KMSP/
SAT...MVFR cigs, bcmg VFR. Wind N 10-15G20 kts.
SUN...VFR. Wind NW 10-15G20 kts.
MON...VFR. Wind NW 5-10 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...Winter Weather Advisory from 2 PM Friday to 6 AM CST Saturday
for Barron-Chippewa-Dunn-Eau Claire-Pepin-Pierce-Rusk-St.
Croix.
&&
$$
DISCUSSION...MPG
AVIATION...BPH
Area Forecast Discussion
National Weather Service Marquette MI
729 PM EST Thu Feb 13 2025
.KEY MESSAGES...
- Scattered to numerous lake effect snow showers off of Lake
Superior will shift increasingly offshore as the night
progresses. Snow accumulations of 1 to 3 inches.
- Temperatures will fall to near -20F in interior western Upper
MI, but with winds near calm in those areas, wind chill
readings will be similar.
- Widespread light to moderate snow expected Friday night into
Saturday. This will result in snow covered and some hazardous
road conditions.
- Lake effect snow downwind of Lake Superior returns Saturday
and continues into next week.
- Cold airmass returns Sunday into early next week.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 351 PM EST Thu Feb 13 2025
Water vapor imagery and RAP analysis show a broad mid-level low over
central Canada, centered along the western shore of Hudson Bay. From
that low, mid-level troffing extends into the Great Lakes region. At
lower levels, 850mb temps per latest RAP analysis range from
-18C over far eastern Lake Superior to -23C over western Lake
Superior. Earlier today, sfc troffing was over eastern Lake Superior
with a couple of mesolows along it. One moved into Alger County late
morning, accompanied by a burst of hvy snow. Another was located n
of Caribou Island. That mesolow is now passing over Whitefish Bay. A
couple of bands of hvy snow on the backside of the low have clipped
ne Luce County. To the w, LES bands streaming into Alger County have
collapsed, and for the moment, there`s not much in the way of -shsn.
Farther w, under the cold air mass, wnw-ese oriented LES bands are
streaming off of western Lake Superior, extending well inland. We`re
starting to get into the time of year where the increasing aftn sun
angle/solar insolation working on the lower albedo forested terrain
may be providing a diurnal component to the inland -shsn, so there
maybe a little of that at play this aftn with -shsn/flurries well
inland.
With sfc high pres ridge passing across the area tonight, winds will
back from wnw to sw by around 12z on Fri, shifting the LES bands
thru the night. With inversions generally around 5kft w and 6kft e,
LES will mostly be on the lighter side. However, the backing winds
will lead to areas of convergence, especially as the land breeze
wind component works in concert with the backing wind. These areas
of enhanced convergence will support bands of mdt snowfall that will
shift northward over western Upper MI and eastward over eastern
Upper MI. Overall, expect accumulations of an inch or two, but
locally around 3 across the w side of the Keweenaw and also to the e
of Grand Marais. In the interior, a generally clear night is shaping
up after late aftn stratocu fades. There are some mid-level clouds
out across the Dakotas, and some of those may stream over the area
overnight. However, overall, tonight will be a good radiational
cooling night in the interior as winds diminish to under 5 mph.
Favored mins around or blo the lowest guidance. This puts min temps
approaching -20F in the interior w. Traditional cold spots may slip
to near -25F. With very little or no wind, temps or apparent temps
in that area will fall short of cold weather advy criteria. Even
where it`s not quite as cold and there`s a bit more wind stirring,
readings don`t reach criteria. Min temps tonight will range up to
around 0F e near Lake Superior.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 202 PM EST Thu Feb 13 2025
Upper air pattern will have a trough in the western U.S. and a
trough in New England 12z Fri. There is also a closed 500 mb low
over western Hudson Bay 12z Fri. Troughing moves into the ROckies
and northern upper Mississippi Valley 12z Sat. Closed low moves to
Lake Winnipeg 12z Sun with troughing in the central U.S. and upper
Great Lakes which changes little by 00z Mon. 850-500 mb q-vector
convergence moves into the western half of the U.P. along with
deeper moisture 00z Sat and remains over the area through 12z Sat
before moving out. Will be dry into early Fri afternoon before snow
moves into the west half by evening. This next system looks to have
about 3-6 inches of snow with it for Fri night through Saturday and
looks like advisories might be needed in parts of the area. Lake
effect snow starts up again by late Saturday afternoon.
In the extended, the GFS and ECMWF show a broad 500 mb trough across
most of the U.S. 12z Mon with a closed low between Lake Winnipeg and
Lake Superior. Upper troughing remains over the area through Thu, so
lake effect snow will continue this forecast period with below
normal temperatures.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 725 PM EST Thu Feb 13 2025
Cold air flowing across Lake Superior will continue to generate lake
effect snow showers, but winds will be veering from wnw to sw
during this fcst period, shifting where the snow showers stream
onshore. IWD and SAW have already scattered or cleared out and
should remain that way through much of the forecast period. At
CMX, expect MVFR cigs and fluctuations btwn IFR and MVFR vis in
-shsn through tonight. Not out of the question that brief LIFR
vis could occur at times. Late tonight/early Fri morning, winds
will back sufficiently to shift lake effect -shsn to the n of
CMX, allowing for improvement to VFR.
&&
.MARINE...
Issued at 202 PM EST Thu Feb 13 2025
20 to 30 knot westerly winds will continue tonight across Lake
Superior. Winds relax below 20 knots Friday into Friday night. On
Saturday, northerly winds look to increase to 20 to 30 knots into
early Sunday into Tuesday. Cold air over the lake will also support
periods of heavy freezing spray Sunday into Tuesday central and east.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Heavy Freezing Spray Warning until 7 AM EST /6 AM CST/ Friday
for LSZ241-242-244-245-248>250-263>266.
Heavy Freezing Spray Warning until 1 PM EST Friday for LSZ251-
267.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...07
AVIATION...Voss
MARINE...07
Area Forecast Discussion
National Weather Service Las Vegas NV
736 PM PST Thu Feb 13 2025
.SYNOPSIS...Valley rain and mountain snow will continue across
large swaths of the forecast area into tonight with a cold front
passage. Gusty southwest winds ahead of the front can also be
expected. Additional showers and thunderstorms may occur
tomorrow. Warm and dry conditions are forecast over the weekend.
&&
.UPDATE...The current forecast remains on track with no major
changes necessary at this time. SNOTELs across the Eastern Sierra
have reported storm total snow amounts of 25 to 35+ inches. Based on
the latest radar and satellite trends, the Eastern Sierra may be
able to squeeze out another inch or two before snow wraps up for
this atmospheric river. Infrared and water vapor satellite imagery
clearly show the upper-level trough driving the AR moisture and
associated showers through our area. The front can be seen currently
sweeping through our forecast area, extending in a curved line from
Barstow-Daggett, CA up into the panhandle of Lincoln County, NV. As
this front continues to work its way eastward, it will drive
moderate-to-heavy showers out ahead of it. Locally, Harry Reid
International Airport has picked up 0.12 inches of precipitation in
the past 30 minutes as these moderate-to-heavy showers move through
the Las Vegas Valley. Once this front pushes off to our east we will
see precipitation chances linger across portions of Lincoln, Nye,
Mohave, and Clark counties tomorrow as we find ourselves on the back
end of this system. Showers tomorrow will have the potential to be
more convective in nature with small hail and thunder possible with
the stronger showers that develop.
&&
.SHORT TERM...Through Friday.
An atmospheric river continues to bring widespread precipitation to
southern Nevada, southeastern California, and northwestern Arizona
through the evening. Snow levels rise throughout the day today due
to warm air advection and should be between 5500 to 6500 feet
tonight. The forecast appears to be on track for the most part,
aside from some over performance of precipitation amounts in Owens
Valley and under performance of snowfall in the Spring Mountains
earlier today. However, a heavier band of precipitation should move
across the area with a cold front passage later this afternoon and
evening. The heaviest snowfall over high terrain outside of the
Sierra should occur with the frontal passage due to increased
moisture and favorable upslope flow. Snowfall rates of several
inches per hour can occur above 9000 feet on Charleston Peak. Most
likely rainfall totals in Las Vegas after this band passes tonight
should be between .25 and .6 inch according to the HREF. The highest
observed precipitation totals at this point have been in the Owens
Valley with totals between .5 and 1.5 inch and localized amounts up
to 2 inches. Rainfall should slow down there one the front passes
and spillover moisture from the Sierra tapers off. The Flood Watch
for Owens Valley remains in effect through this evening. The Winter
Weather Advisory for Lincoln County ends at 10 PM tonight as
snowfall should largely end after the frontal passage, but the
Winter Storm Warnings for the Sierra, White Mountains, Spring
Mountains, and Sheep Range remain until 4 PM tomorrow to cover
additional snowfall and gusty winds.
The strongest winds seen so far have been in Esmeralda, Inyo, and
Nye counties with southerly gusts peaked around 45 mph. These winds
should decrease tonight and the Wind Advisory for these areas along
with Lincoln County expire at 10 PM PST tonight. Gusty southwesterly
winds are still forecast for parts of San Bernardino, Clark, and
Mohave counties through tonight ahead of the cold front, but have
underperformed so far. Wind gusts between 40 and 50 mph may hang on
in western San Bernardino County through most of Friday and Wind
Advisories have been issued to reflect these trends.
The main stream of moisture advection from the Pacific Ocean will be
pushed east tonight as the upper level trough starts to exit the
area. However, a combination of residual moisture and surface
heating may lead to isolated shower and thunderstorm development in
southern Nevada and northwestern Arizona on Friday. Cool
temperatures aloft may allow for small hail with some cells. Any
rain or snow accumulations should be light.
.LONG TERM...Saturday through Wednesday.
Dry northwesterly flow will be in place across the southern Great
Basin and Mojave Desert on Saturday as a ridge of high pressure
builds into the area. The dry weather will persist on Sunday with
temperatures at or slightly below their seasonal normals which is in
the low 60s in the Las Vegas Valley.
The next system approaches from the northwest on Monday, and should
generally be dry but a showers couldn`t be ruled out across then
northern portions of Lincoln County. However, behind the system will
be some gusty north winds, particularly down the Colorado River
Valley with probabilities of reach 40+ mph in the 35-45% range.
We`ll need to monitor to see if there is the need for a Lake Wind
and Wind advisory. Weak systems moving down the front side of a West
Coast ridge will generally keep temperatures from moving very much
through mid week.
&&
.AVIATION...For Harry Reid...For the 00Z Forecast Package... Periods
of rain will continue through the evening, and the latest HRRR
guidance shows a band of heavier precipitation moving across the
valley between 02Z and 05Z. CIGs have improved slightly over the
past hour, but this is expected to be short-lived and fall back to
the 3kft to 4kft AGL range as the precipitation band moves through.
Visibilities may fall to 3SM with that band as well. With the
precipitation in the area today, winds have remained light. However,
once the precipitation band passes, south-to-southwest winds are
expected to increase and remain elevated through Friday afternoon.
Conditions will gradually improve tomorrow, although a few isolated
convective showers will be possible during the late afternoon and
evening as the trough axis passes across the area.
For the rest of southern Nevada, northwest Arizona and southeast
California...For the 00Z Forecast Package...MVFR to IFR ceilings and
visibilities will continue through the evening as a band of
precipitation moves across the area. CIGs falling to around 2kft
to 3kft AGL, along with visibilities lowering to less than 4SM are
possible this evening and tonight as the band passes. Increasing
south-to-southwest winds will be seen across much of the region this
evening and overnight once the precipitation passes. Once the
winds do increase, valley locations will see 15 to 25 knots gusts,
while the higher elevations could gust to 35 to 45 kts. Conditions
will improve from northwest to southeast late this evening and
overnight. However, a few scattered showers and possibly a
thunderstorm or two are possible late Friday, primarily over the
higher terrain north and east of the Las Vegas area.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
UPDATE...Stessman
SHORT TERM...Meltzer
LONG TERM...Czyzyk
AVIATION...Planz
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