Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/02/25
Area Forecast Discussion
National Weather Service Bismarck ND
848 PM CST Sat Mar 1 2025
.KEY MESSAGES...
- Temperatures around 10 to 20 degrees above average statewide
Sunday and Monday, with forecast highs mainly around 40 north
to the 50s south.
- Low to medium chances (30 to 60 percent) for rain and snow
Monday night through Tuesday, with temperatures falling back
to near average (highs in the 30s).
- After cooler temperatures midweek, another warmup is possible
at the end of the week and through the weekend.
&&
.UPDATE...
Issued at 846 PM CST Sat Mar 1 2025
The low stratus continues a slow but steady erosion from the
west, having reached a line of near Westhope to Wishek as of 830
PM. Expect these trends to continue into the overnight hours. No
significant forecast changes are needed with this update.
UPDATE
Issued at 536 PM CST Sat Mar 1 2025
Pesky cloud cover has finally eroded to the Highway 83 corridor, but
still persists to the east. Recent RAP guidance suggests the lower
stratus could continue into the overnight hours, primarily along a
corridor from near Bottineau to Jamestown.
A mention of patchy fog was added to the forecast late tonight into
Sunday morning along the Canadian border in northwest North Dakota,
extending down to the Tioga/Stanley areas. This fog could be driven
by differential cooling along the retreating stratus over a
lingering snowpack, and the Tioga/Stanley areas are known to be
prolific for fog formation.
&&
.DISCUSSION...
Issued at 200 PM CST Sat Mar 1 2025
Western and central North Dakota currently sits under the
influence of northwest flow aloft. Clouds will continue to
diminish from west to east through the day, giving way to a
mostly clear sky overnight and a sunny Sunday.
A progressive ridge axis will move through on Sunday, followed
by a dry embedded shortwave. The parent axis then moves into
western North Dakota Sunday night into Monday morning as it
deamplifies and we transition to split flow aloft. This pattern
will mean more above normal temperatures on Sunday and Monday
(normal high temperatures for this time of year generally range
from the upper 20s east, to the low to mid 30s west), with highs
mainly ranging from around 40 across the north, to the 50s
south. On Sunday, we do have a shot to rise into the lower 60s
across the far southwest and we may only rise into the mid 30s
northwest on Monday behind an advancing cold front.
On Monday night into Tuesday morning, a Colorado Low will kick
out into the southern and central Plains as a northern stream
wave spreads across the northern Plains. This will mean
increasing chances (30 to 60 percent) of rain and snow Monday
evening, gradually transitioning to mostly snow on Tuesday
morning. Some snow snow showers may linger in the afternoon
under cyclonic flow aloft. Given the split flow regime (the most
likely scenario at this time), precipitation amounts are
generally expected to be fairly light. NBM probabilities of
liquid amounts of a tenth of an inch or greater max out in the
30 to 60 percent range across the south central and southeast
(highest probabilities southeast which may see a glancing
influence from the southern low). Increasing the threshold to a
half inch of liquid, and the probabilities max out around 20
percent southeast. Regarding any accumulating snow, NBM
probabilities only max out around 20 percent for an inch or
greater. A tightening pressure gradient behind these waves will
also lead to some windy conditions (winds out of the north) on
Tuesday, especially south central and southeast. After Tuesday,
the rest of the work week looks mainly dry.
Regarding temperatures through the rest of the period, we will
see highs mainly in the 30s on Tuesday and Wednesday behind the
cold front with a modest warmup to end the week. Highs on
Thursday and Friday are currently forecast to range from the
lower 30s to lower 40s and then a more significant warmup is
possible through the weekend. That being said, NBM temperature
spreads start to increase Friday.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 846 PM CST Sat Mar 1 2025
MVFR ceilings will continue across the eastern half of this
state through late tonight, including KJMS and surrounding
areas. Otherwise, VFR conditions are mostly expected through
the forecast period. Some patchy fog could develop near the
Canadian border in northwest North Dakota late tonight into
Sunday morning. Winds will remain southerly around 5-10 kts.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Hollan
DISCUSSION...ZH
AVIATION...Hollan
Area Forecast Discussion
National Weather Service Billings MT
111 PM MST Sat Mar 1 2025
.KEY MESSAGES...
- Sunny and warm through the weekend.
- Still some minor snowmelt and ice jam potential leading to
localized low land flooding.
- Rain transitioning to snow is forecast Monday evening into
Tuesday. Snow amounts remain light around a trace to 3 inches
over the lower elevations, greatest in the foothills.
&&
.DISCUSSION...
Through Sunday night...
Upper level ridge will bring us dry & mild weather through the
remainder of the weekend. High temps tomorrow should reach the
upper 50s to lower 60s most places and nighttime lows will be
seasonably mild. No chance of precip through Sunday night. As
heights begin to fall as Pacific low moves into the great basin, a
shift to light northerly winds will occur late Sunday night. This
will signal the start of a cooling trend early next week.
The only real forecast issue is fog potential. There was not any
fog of note in our cwa this morning, but current observations in
southeast MT show dew points a few degrees higher than at this
time yesterday (low 30s at Miles City and Baker), likely due to
ongoing snow melt into a stagnant air mass with light winds.
Tonight`s low temps should fall a bit cooler than these values.
The HRRR insists that the fog will remain in northeast MT, but
feel there is enough of a risk to add patchy valley fog along the
Yellowstone near Miles City from 09-15z. Something to watch.
JKL
Monday through Saturday...
Precipitation is forecast to return to the region early this
week. At this time, the best chance of precipitation is Monday
evening through Tuesday morning when there is a 40 to 85 percent
chance over the lower elevations, highest in south- central
Montana, and a 70 to 90 percent chance over the mountains, highest
in the Beartooth- Absarokas. While precipitation will fall as all
snow in the mountains, precipitation looks to start out as rain
over the lower elevations before transitioning to snow Monday
night. By the Tuesday morning commute, the precipitation type is
expected to be all snow. With that said, with weather system is
not expected to bring a whole lot of precipitation to the region.
At this time, the liquid precipitation (melted snow) forecast
ranges from a trace to 0.30 inches, highest along the foothills of
south-central Montana and lowest north of Billings and in far
eastern Montana around Miles City, Baker, Broadus, and Alzada. Due
to a lack of cold air with this system, snow ratios and
subsequent snow amounts will be lower as well. At this time,
anywhere from a trace to 2 inches of snow is forecast over the
lower elevations. Along the immediate foothills of the Beartooth-
Absarokas, 1 to 3 inches are forecast. Over the mountains, 2 to 6
inches are forecast. Periods of light snow may continue over the
mountains of south-central Montana Wednesday (20 to 40 percent
chance) before another chance of rain/snow, mostly wet snow,
returns to the lower elevations of south-central Montana Thursday
(10 to 45 percent chance). Again, any precipitation that falls
mid-week looks to generally be light. By the end of the week into
the weekend, drier conditions will return.
With the unsettled weather, cooler and more seasonal temperatures
will remain over the region this week. As we get into next
weekend, temperatures look to gradually warm again, but
uncertainty remains on just how warm we get. With the warmer
temperatures next weekend, windy conditions will also return,
especially to the foothills west of Billings. Arends
&&
.AVIATION...
VFR will prevail regionwide over the next 24 hours, under strong
high pressure aloft. Occasional gusts to 25 knots will be felt
along the western foothills (including KLVM) until 00z late this
afternoon. Winds will be lighter tonight & Sunday. Cannot rule out
fog late tonight along the Yellowstone near KMLS, but chances are
low (20%) at this time. Will monitor through the evening. JKL
&&
.PRELIMINARY POINT TEMP/POPS...
Sun Mon Tue Wed Thu Fri Sat
-----------------------------------------------------------
BIL 032/059 033/050 031/039 024/046 029/042 025/047 031/055
00/U 02/R 85/S 21/B 23/S 11/U 01/N
LVM 031/059 030/042 029/035 022/043 025/036 020/041 027/047
00/U 03/O 63/S 12/S 33/S 10/N 01/N
HDN 026/059 029/049 028/038 021/046 025/043 022/048 028/057
00/U 01/E 96/S 11/B 12/S 11/U 01/B
MLS 027/060 031/052 029/035 021/041 024/041 021/045 028/054
00/U 00/E 42/S 00/B 01/B 00/U 00/N
4BQ 030/061 030/052 029/034 021/042 027/041 023/044 029/054
00/U 00/B 54/S 00/B 11/E 10/U 00/U
BHK 026/059 028/051 024/032 016/038 019/040 017/041 023/049
00/U 00/B 34/S 10/B 01/B 00/U 00/N
SHR 028/060 028/048 024/033 016/043 022/038 018/041 021/052
00/U 01/N 76/S 11/B 14/S 31/B 00/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Grand Forks ND
1000 PM CST Sat Mar 1 2025
.KEY MESSAGES...
- Large system to impact the central CONUS early week with a
range of potential impacts to our region.
- Temperatures remaining above average through the week.
&&
.UPDATE...
Issued at 1000 PM CST Sat Mar 1 2025
The area of stratus has held together and is progressing
eastward over eastern ND as surface high retreats and surface
gradient increases from the west. This has not been well handled
by previous guidance but short range guidance such as the HRRR
finally match up a bit better and reflect this transitioning
across our entire CWA through the overnight period. Clearing to
the east has allow temperatures to drop a bit faster than
previous forecast reflected while temperatures in the west have
leveled off due to insulation from the low clouds. Adjustments
were made to reflect these trends through the overnight/Sunday
morning period.
UPDATE
Issued at 707 PM CST Sat Mar 1 2025
Low clouds have lingering in the Devils Lake Basin with higher
clouds showing more clearing trends in the east. Temperatures
have been snow to drop in our west and would be expected where
low clouds are persisting, but so far trends are reflected.
Adjustments were made to reflect sky trends, otherwise forecast
remains on track.
&&
.DISCUSSION...
Issued at 1258 PM CST Sat Mar 1 2025
...Synopsis...
The amplified pattern will become more progressive with meridional
upper flow transitioning to split flow with the weakening of the
northern stream jet and developing deep layer troughing in the west
becoming the main driver of the pattern into early next week. A
coupling of the northern stream entrance region over the Great Lakes
and southern stream exit region in the central plains will lead to
rapid cyclogenesis in the plains with a Colorado low type track into
the Midwest/Great Lakes Monday into Wednesday. Broad deformation in
the mid levels (850-500mb) combined with strong WAA provided by the
northward advancing low Tuesday will lead to broad precipitation in
the northern plains/midwest Tuesday/Wednesday. EFI paints the signal
for increased winds from the tightening pressure gradient during
this period with CIPS analogs showing a 60% chance for gusts over
30kts Tuesday/Wednesday. NBM QMD also agrees well with the prospect
of increased winds.
CIPS analogs is tool that generally shows the most forecast skill in
large synoptic events. What its showing for the first half of next
week shows varying historical analogs of blizzards and late spring
wind events to a general swath of 3-8" of snow. With that said there
is clearly a wide range of possible solutions at this point with the
main sticking points so far being precip (could be rain or snow)
will occur within the forecast area though is most probable in the
south and east. Next there is the high certainty in wind being a
factor but with the track of the low well to the south likley not
being quite as strong as yesterday and with late arrival of cold air
could be a non factor in potential to combine with snow.
- Scenario 1
Overall a more southern low track would result in less interaction
between the colder Canadian airmass from the north and the pipeline
of gulf moisture from the south leading to a mostly rain event for
the area. NBM currently shows around a 50% chance for > 0.25" of QPF
for areas south of Valley city to Bemidji (very subject to change in
location still) with only a 20% chance for 2" or more of snow. The
majority of guidance keeps the main swath of snow in MN/IA/WI where
cold air and QPF overlap for a longer duration on Wednesday.
- Scenario 2
In a different outcome say cold air arrives sooner and QPF reaches
slightly farther north in conjunction. In this case more robust
dynamics would lead to more snow for the area though still favoring
the south and east. With the overlap of falling snow, strong winds,
and accumulating wet snow this would hold a much higher impact
ceiling for the region though only a few individual ensemble members
show this and thus it appears to be a low chance outcome at this
time.
- Extended forecast
Beyond the potentially messy system early in the week highs look to
remain above average into next weekend. Averages to begin March for
the region are in the mid to upper 20s for highs and around 10 by
the next of this week for lows. Highs as ridging re-establishes past
mid week climb into the 30s and even 40s by next weekend. Lows in
the teens and 20s wont put quite as much of a dent into the
remaining snow as the past few days but are a far cry from the lows
of mid February so no complaining here. Overall looking a a drier
trend past the early week system.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 536 PM CST Sat Mar 1 2025
MVFR ceilings are lingering at KDVL along the western edge of
surface high pressure and is likely to prevail early in the TAF
period, with gradual improvement shown late evening/overnight
by guidance as winds begin to increase and advect drier air into
the region from the west. There is a chance it could linger
longer into the night, but eventually VFR should return as the
pattern shifts and low pressure builds east. VFR is expected to
prevail at other TAF sites in eastern ND and northwest MN though
the TAF period. Southerly winds gradually increase at all sites
from the south as gradient increases, with winds 12-15kt
(occasional gusts to 20kt) Sunday afternoon.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...DJR
DISCUSSION...TT
AVIATION...DJR
Area Forecast Discussion
National Weather Service Goodland KS
845 PM MST Sat Mar 1 2025
.KEY MESSAGES...
- 20% chance of fog tonight into Sunday morning for SW Nebraska;
with better chances and coverage Monday morning.
- Start of active pattern Sunday with near critical fire
weather, gusty winds up to 50 mph and the possibility for
strong to severe storms.
- Strong winds in excess of 55 mph likely across the area on
Tuesday. Strongest winds currently favoring along and west of
Highway 25.
- Rain changing to snow early Tuesday morning will lead to
blowing snow concerns throughout the day with the most likely
impacts favoring along and west of Highway 27. Accumulating
snow is forecast but low confidence in amounts at this time.
&&
.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 154 PM MST Sat Mar 1 2025
Mid level ridging is ongoing across the Intermountain west with a
developing system across SW California. Ongoing subsidence due
to the ridge is leading to clear skies across the area as high
temperatures rise into the upper 50s to mid 60s across the
area. For tonight am watching the potential for some patchy fog
development across Hitchcock and Red Willow county as winds
remain from the ESE which is climatologically favored. Other
than the typical NAM and other moist bias models visibility
forecasts are not quite picking up on it yet. A consistent
signal from the RAP and increasing boundary layer moisture from
11Z-14Z does give me enough confidence from a set up perspective
to include the patchy fog wording into the forecast for now
confidence is around 20-30% in fog development at this time with
around 5% chance of dense fog concerns.
Sunday, the above mentioned low currently across SW Colorado will
begin moving towards the southern Plains. Current guidance does
suggest that this low will remain south of the area so have opted to
cut down rain chances across the area. Did keep "chance" wording in
for Greeley, Wichita, southern Logan and Gove counties as NAM mid
level moisture does keep some moisture present across those counties
but anything other than a window for light rain looks to remain to
the south of the area. After that low moves through during the
evening, moisture advection will begin to move into the area. Am
currently seeing a fairly strong signal for fog so have added that
wording into the forecast; also wouldn`t be surprised if we have
some dense fog potential as dew points rise into the 40s across the
area. Highs for the day Sunday are forecast to be similar to today
in the upper 50s to upper 60s.
Monday, fog perhaps dense is forecast to be present through the
morning hours. Another developing low from the west will end any fog
potential as a dry line pushes into western Kansas. Winds will also
begin to increase through the day as the low moves in and deepens.
Wind gusts up to 50 mph will be possible leading to some fire
weather concerns behind the dry line. There is some concern for
critical conditions to occur but the question will be for how long
will there occur. Will also need to continue to watch for even drier
air behind the front as is typically what does occur in reality, for
now to get the lower RH values into the forecast went with a blend
of the NAM and NBM.
Will also be watching for a threat for strong to even potentially
severe storms across western portions of the area Monday afternoon.
A triple point is currently forecast to set up across NW portions of
the forecast area. NAM forecast soundings show MUCAPE of 500-1000
j/kg which yes is a little meager, but is made up for with unstable
mid and low level lapse rates of 8.5-9C. A noticeable curvature
in the low levels and very strong 0-6km shear thanks in part to
the proximity of the low may also support the potential for
some large hail up to 1.25 inches. Will also be watching for the
potential for a tornado as well along the corridor of the
triple point due to strong surface convergence and 0-3km CAPE of
75-200 j/kg. With the dryness and warmth of the past couple
days will also need to keep an eye on blowing dust with any
convective outflows as well. Its not the most slam dunk severe
weather set up from instability purposes but does need to be
watched due to how dynamical this system is.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
Issued at 154 PM MST Sat Mar 1 2025
Monday night and into Tuesday precipitation is forecast to
continue from the NW as the low continues to deepen and dry
slotting occurs across the eastern portions of the area. A
transition from all rain to snow is expected to occur. How
quickly this occurs will depend on how early this occurs. A
slower transition to snow will lead to lower amounts and a
quicker transition will lead to higher amounts. To further
complicate the snow forecast is the presence of some MUCAPE
across eastern Colorado as well leading to banding potential. I
did increase amounts by having the transition from rain to snow
occur sooner leading to 1-2.5 inch forecast amounts for snowfall
but as just mentioned confidence in exact amounts is low at
this time due to the banding potential.
The main story with this system does appear to be the winds.
Confidence is increasing with the potential for 55+ mph winds across
most of the area. The main question will be just how strong will the
winds be? Forecast soundings are fairly consistent in 50+ knot winds
starting around 830mb with 60 knot winds just above that. With the
stratus and ongoing precipitation general mixing will not be
achieved but will be dependent on overall baroclinicity and
associated pressure rises with the system as it slowly moves
off. Current forecast has around 55-60mph winds out towards the
Highway 25 corridor and 60-65 mph winds across eastern Colorado.
However if what is seen in soundings is correct would not be
surprised if a rogue 70 mph wind gust occurs. With the wind and
snow potential in place blowing snow will also become a concern
as well. This snow doesn`t look to be as dry as we have seen the
past few months will help but with how strong the winds are
forecast to be near blizzard to locally blizzard conditions can
not be ruled out. Remember, you don`t need to have high snowfall
amounts for impactful conditions to occur due to the reduction
in visibility. Snowfall and any lingering rainfall across the
east will slowly come to an end throughout the afternoon hours.
Wednesday, mid level ridging returns to the region bringing a
quick reprieve to the active pattern. This will be short lived
however as more troughing returns to end the week with
additional rain and snow chances through next weekend. Snow
chances may be a bit better as guidance suggests that the air
mass will be a little colder but with this still 5-7 days many
changes will occur with the favored locations for snowfall and
the evolution of this next system.
&&
.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 844 PM MST Sat Mar 1 2025
A low level jet in combination with an inversion are creating
better chances for low level wind shear at both terminals.
For KGLD, VFR conditions through the forecast period. Winds,
south-southeast 10-15kts w/ gusts to 25kts possible from 15z
Sun-02z Mon. LLWS 06z-15z Sunday flight level 020 190@40kts.
For KMCK, mainly VFR conditions expected through the forecast
period. Low chance for MVFR fog to occur from 12z-17z. Winds,
south-southeast 10-15kts w/ gusts to 20kts from 12z Sun-00z
Mon. Much of the forecast period will see LLWS at flight level
020 180-200@35-40kts. At this time, only 17z Sun-00z Mon not
expected to see any.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.
&&
$$
SHORT TERM...Trigg
LONG TERM...Trigg
AVIATION...JN
Area Forecast Discussion
National Weather Service Marquette MI
643 PM EST Sat Mar 1 2025
.KEY MESSAGES...
- Snow showers and wind continue to diminish into tonight,
followed by mostly dry conditions and a warming trend.
Widespread above freezing temperatures are expected for Monday
and Tuesday.
- Strong low pressure system will bring strong winds, rain and
wet, heavy snow to the Great Lakes Tuesday night into
Wednesday. Exactly how much and who will see rain vs snow will
depend on the track of the storm, which is uncertain at this
time.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 107 PM EST Sat Mar 1 2025
Broad troughing extending south from Hudson Bay while upstream
surface ridging originating from a 1028mb high over western
Minnesota ahead of stout mid-upper level ridging are apparent on
GOES Water Vapor imagery and RAP analysis. This positions Upper
Michigan under the effects of lingering cyclonic flow and increasing
subsidence and dry air to our west. The results have been slowly
diminishing lake effect snow showers and relaxing winds from west to
east. Scattered clouds and sunshine has been noted outside of the
north to northwest wind snow belts. So far, daytime temperatures
have topped out in the mid-teens in the warmer, sunny spots of
Menominee County while the rest, as of this writing, have climbed to
10F or remained in the single digits.
As we progress through the remainder of the afternoon, ridging will
continue to press eastward into our forecast area, resulting in
continued diminishing lake effect and lightening winds.
Additionally, skies are expected to begin clearing this afternoon
across the west. Daytime temps are expected to climb a little more,
resulting the south-central warming potentially near 20F while the
rest of the region breaks into the teens. With the clear skies
expected to spread across the west half tonight and winds going
light, effective radiational cooling is expected. Trended the
forecast toward the NBM10th and MOS guidance, which pulls overnight
temps to near or below zero for the interior west half and far east.
Could easily be an overachieving night in these spots given PWATS
below 0.10 inches, fresh snow, and mesoscale/ drainage
from the higher terrain. Lake effect snow should continue east of
Marquette this afternoon and overnight; however, current inversion
heights estimated near 5-6k feet will fall as subsidence increases
and dry air builds in, resulting in lighter snow showers. Snow
accumulations should largely amount to 1-4 inches in these spots,
highest likely across eastern Alger/northern Schoolcraft and
potentially near the Marquette-Alger County line where land breeze
convergence tonight could result in stronger low level convergent
banding.
&&
.LONG TERM /SUNDAY THROUGH SATURDAY/...
Issued at 432 PM EST Sat Mar 1 2025
With LES ending on Sun, the main focus of the extended fcst becomes
a strong CO low impacting the region Tue-Wed. This system is
followed up by a shortwave and clipper low from the NW on Fri. With
WAA from SW flow, warmer than normal temps are expected early next
week with highs Mon/Tue in the upper 30s to mid 40s and lows in the
20s to low 30s. Temps return to near normal by the end of the work
week with highs in the upper 20s to 30s and lows in the teens to low
20s.
High pressure centered just S of Lake MI Sun morning shifts E toward
the Atlantic Coast by Mon morning. Meanwhile, mid level ridging
builds over the N Plains and a vigorous shortwave over the S Plains
tracks ESE toward the Lower MS Valley. An additional shortwave drops
SE on Sun over E Lake Superior and Upper MI. Winds back W to SW
through the day as a result of the shifting high pressure, but
some lingering isolated LES showers continue over the east
through the day. QPF will be limited so despite ideal SLRs near
20:1, accumulations will also be low (1" or less). Impacts are
not expected with most remaining dry under partly cloudy to
mostly sunny skies. Sun highs are expected in the mid 20s to low
30s. Sun night lows could bottom out early into the single
digits interior W with teens elsewhere, but this will depend on
the strength of the increasing WAA and how clear the skies are
during this period. Leaned colder than the NBM toward the MOS
guidance. Weak isentropic ascent and WAA on Mon increases cloud
cover mainly to the N during the day. This seems to be enough
lift for CAMs to yield model reflectivity up to 10 dBZ, but dry
weather should persist as model soundings indicate fairly dry
low levels.
Attention then turns to the main event of the extended fcst. On Mon,
a deep trough over the Rockies digs into the Plains. As a result, a
CO low develops and tracks E off over the Central Plains on Tue. The
trough and sfc low then lift NE across the Great Lakes on Wed. PWATs
show gulf moisture surging N toward the region and the 3/1 0Z ECMWF
EFI highlights more impactful snow amounts over Upper MI during this
event with shading up to 0.9 over the N central and a SoT>0 over
much of the UP. WAA and isentropic ascent well ahead of the system
sends a light round of rain NE over the UP late Mon night into Tue.
Model soundings do indicate low potential for some freezing rain
(~30% chance over central and E Upper MI), however ice accumulations
likely would be limited to a glaze Mon night. Will continue to
monitor this as even a little ice could create hazardous conditions
for the Tue morning commute. With temps warming up for most outside
the Keweenaw into the 40s, mainly rain is expected the remainder of
the day Tue. Where the fcst becomes less certain is Tue night
through Wed when the low tracks NE from N MO to Lake Huron as there
remains some spread in sfc low track among the available guidance;
this is also the period when a W to E transition of rain/snow over
to snow is anticipated. How far N the low tracks and how quick it`s
able to arrive impacts the timing of cooling over the UP and how
quick rain changes over to rain/snow and eventually all snow.
Currently the greatest uncertainty remains over the central and E
UP. The ECMWF track is a bit further S and slightly slower than the
GFS, cooling off the airmass quicker than the GFS and resulting in a
faster transition over to snow. This lines up well with the greatest
lift and QPF, yielding higher snow amounts than the GFS. Also aiding
in snow amounts is the steadily falling 850 mb temps over Lake
Superior on Wed, eventually yielding marginal delta-ts for lake
enhancement as well as NE upslope flow. System QPF is fcst around
0.75" to 1.25", highest in areas supported by upslope and lake
enhancement. With wetter SLRs near 10:1, several inches of wet snow
are likely over the W and N central, but totals across the rest of
the UP will depend on how p-type transitions occur. The 3/1 0Z LREF
probs of 6"/24hr are around 50-75% over the N central and W, but
only 25-50% elsewhere, lowest near Lake MI.
A tight pressure gradient and ~45kt LLJ overhead with this system
also bring strong wind potential to the CWA on Wed. ENS probs of
gusts up to at least ~40 mph are between 40-70% across much of the
UP with prob up to 90% near Lake Superior. GFS model soundings
indicate potential for gusts as high as 50 mph! Gusty winds and
heavy wet snow could lead to power outages and difficult travel.
Some Winter Weather headlines will likely be needed when fcst
confidence increases.
In the wake of this system, cooler NW flow with the assistance of a
passing clipper system and shortwave keep 15-30% chance PoPs in the
fcst the remainder of the extended.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 643 PM EST Sat Mar 1 2025
VFR conditions will generally prevail across all of the TAF sites
through the TAF period. There is a 30% chance of brief reductions in
visiblity at CMX due to snow and blowing snow this evening. WNW
winds of 10 to 15kts will become light late tonight.
&&
.MARINE...
Issued at 453 PM EST Sat Mar 1 2025
NW winds of 20-30 kts over the east with mainly 20 kts or less over
the west this afternoon gradually fall below 20 kts across the lake
by around midnight tonight as high pressure moves to the south.
Winds are expected to remain 20 kts or less through Monday night as
the high pressure moves toward the Atlantic. Attention then turns to
a Colorado low ejecting off the Rockies on Tuesday, increasing NE
winds to 20-30 kts into Tuesday night (strongest winds over the west
half). As the low transits south of the lake, winds continue to
increase across the lake as they back north for Wednesday. Gales to
at least 34 kts are expected with high end gales to 40-45 kts
increasingly likely on Wednesday. Chances for storm-force winds
to 48+ kts are around 10-30%, highest over the east half of the
lake Wednesday afternoon and evening. Winds back NW Wednesday
night, settling below 34 kts in the west by midnight and the
east by around sunrise on Thursday.
Moderate freezing spray returns on Wednesday with heavy freezing
spray possible Wednesday night (~30% chance). Peak wave heights are
expected up to 10-12 ft over the west Wednesday afternoon and
between 12-15 ft over the east Wednesday night.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Heavy Freezing Spray Warning until 1 AM EST Sunday for LSZ243-
244-249>251-264-266-267.
Heavy Freezing Spray Warning until 7 PM EST this evening for
LSZ245>248-265.
Lake Michigan...
None.
&&
$$
SHORT TERM...JTP
LONG TERM...Jablonski
AVIATION...RM
MARINE...Jablonski