Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/15/24
Area Forecast Discussion
National Weather Service La Crosse WI
531 PM CST Wed Feb 14 2024
.KEY MESSAGES...
- Area wide snowfall around 1-2 inches expected tonight. There
will be two different snowbands with embedded heavier
snowfall amounts. One along and north of a line from Mankato
through Eau Claire to Wausau and another from Viroqua/Richland
Center east through the Dells to Fond Du Lac.
- Blustery conditions expected Friday into Saturday, with a return
to warmer than normal temps next week.
- After tonight, no mentionable precipitation through the middle
of next week.
&&
.DISCUSSION...
Issued at 258 PM CST Wed Feb 14 2024
Tonight: Rain Changing Over to Snow
Latest high resolution model guidance shows a similar footprint as
last night/this morning`s forecast, with higher confidence in the
southern snowband`s forecast snowfall amounts. The advertised
northern snowband, which is expected to impact those along and north
of a line from roughly Mankato through Eau Claire to Wausau, is
mostly the same snowfall amounts with just a subtle shift northward.
Meanwhile, the southern snowband snowfall amounts have increased
quite a bit and trended just slightly to the south. The northern
snowband has strong frontogenesis forcing while the southern
snowband has strong background QG dynamic forcing with embedded fgen
forcing on top of that, which has led to an increase in QPF.
Individual HREF members and their model soundings show strong
agreement in the temperature profile in the boundary layer, with
subtle differences in the timing for when rain changes fully over to
snow. So, there`s two things that bring uncertainty into the
snowfall forecast. The first being when exactly does rain change
over to snow and how much QPF to we lose to rain vs snow? The second
is for any potential shift in the snowbands themselves. As usual
with these types of weather systems, a subtle shift can be the
difference between an inch of snow and 3 to even 5+ inches of snow
in just 10 or so miles. All of this precipitation is expected to
only persist for 3-4 hours at any given location, so remaining
as rain a touch longer would really start to cut into snowfall
amounts. To throw another wrinkle in the mix, the latest 18Z
HRRR now shows less snow across the northern snowband and a
southward shift to the southern snowband. This is something we
will continue to monitor into the evening hours and may need to
adjust the Winter Weather Advisory across our area.
Thursday into Saturday: Feeling Colder, but Still Near Normal
Not much has changed in the temperature and wind forecast for
Thursday into Saturday as a cold front is forecast to sweep across
the region on Friday. Behind the front, it will feel very cold for
most of us as we have gotten used to the abnormally warm
temperatures for January and February across the region. Look for
wind chills to fall into the single digits to teens above zero
through the day on Friday. Overnight Friday into Saturday, wind
chills will drop to near zero with a few single digits below zero
expected across northern and central Wisconsin.
Sunday and Beyond: Warming Up and Remaining Dry
Winds remain elevated on Sunday, but temperatures will climb
slightly above normal in the mid 30s to near 40 across the region.
With an atmospheric river expected across the West Coast and split
flow across the CONUS, the Upper Midwest region is expected to
remain dry under W to NW flow into the middle of next week.
Clustered ensemble guidance shows considerable uncertainty for the
temperature forecast through next week, but most of the members show
above-normal temperatures to persist. There is a cluster,
predominately consisting of GEFS members, that shows below normal
temperatures under the NW flow but the chance of this solution is
generally under 10%.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 531 PM CST Wed Feb 14 2024
A quick round of rain/snow will spread east this evening, with
the bulk of the impacts expected from late this evening through
the predawn period Thursday, conditions improving west to east.
A period of IFR to perhaps LIFR conditions will accompany the
snow, but with temperatures prior to precip onset above
freezing, the changeover time will depend on the
intensity/location of heavier bands. In general, snow will fall
in a 3 to 5 hour window at any given location. Winds will also
increase from the north overnight into Thursday with some gusts
up to 25 kts. VFR conditions will return in the wake of the
precip Thursday morning.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory from 9 PM this evening to 6 AM CST
Thursday for WIZ017-029-032>034.
Winter Weather Advisory from midnight tonight to 6 AM CST
Thursday for WIZ041>044-053-055.
MN...Winter Weather Advisory from 9 PM this evening to 6 AM CST
Thursday for MNZ079-086-087.
Winter Weather Advisory from midnight tonight to 6 AM CST
Thursday for MNZ088-096.
IA...None.
&&
$$
DISCUSSION...JAW
AVIATION...JM
Area Forecast Discussion
National Weather Service Cleveland OH
952 PM EST Wed Feb 14 2024
.SYNOPSIS...
High pressure will depart to the east tonight allowing a fast
moving low pressure system and associated cold front to move
through the southern Great Lakes Thursday. High pressure will
briefly return Thursday night into Friday before another fast
moving low pressure system moves across the region late Friday
into Saturday.
&&
.NEAR TERM /UNTIL 6 PM THURSDAY EVENING/...
930 pm...Starting to see the makings of Thursday`s system on
satellite this evening, with the Air Mass RGB suggesting the
intake of high PV air into the developing low pressure across
portions of the Central Plains. May need to adjust the Wind
Advisory area and/or time, but will defer to the next shift as
more data becomes available. The recent 0Z hires guidance is
hinting at a convective-like rain band along the cold front in
the late morning/early afternoon in addition to drier low-
levels underneath a weak inversion. If these trends persist,
wouldn`t be surprised to see a few higher winds near 850 mb
translating down to the surface.
Previous Discussion...
A quiet evening is in store as an 1025 mb surface high will
bring much drier air and subsidence. Cloud cover will quickly
increase again from west to east the second half of the night as
a compact mid/upper shortwave and associated surface low move
into the western Great Lakes. Developing southerly flow and warm
air advection ahead of this system will cause low temperatures
to be reached by about 06Z tonight (mid/upper 20s with a few low
20s in NW PA) before temperatures begin to slowly rise the
second half of the night.
The aforementioned shortwave will progress rapidly through the
southern Great Lakes Thursday with a 140-150 knot H3 jet streak
rounding its base. The left exit region of this jet will allow the
surface low to modestly deepen as it tracks from near Chicago
Thursday morning to New England by Thursday night where it will
reach at least 995 mb. The surface low will pass over or just north
of Lake Erie during the afternoon along its path, and its parent
mid/upper shortwave is quite compact. This pattern recognition and
climatology supports a period of gusty SW winds veering to westerly,
especially in NW Ohio, the central highlands, and along the
lakeshore. A 50-58 knot low-level jet will punch into northern Ohio
late Thursday morning into the afternoon in response to the
aforementioned H3 jet streak, with this jet veering from SW to W
with the cold frontal passage. This builds confidence in the pattern
recognition for gusty winds, so issued a Wind Advisory for most
areas along and west of I-71, as well as along the lakeshore east of
Cleveland through the lakeshore of Erie County, PA. The fly in the
ointment is the window of strong winds. NAM and RAP BUFKIT soundings
show a low-level inversion during the morning, likely due to light
precip in the warm air advection and isentropic ascent ahead of the
warm front. This will keep winds in check during the morning,
although some gusts over 30 knots are possible. As the cold front
moves through from west to east late Thursday morning through mid
afternoon, the forecast soundings suggest a period of much better
mixing into the 850 mb layer. This will tap into that aforementioned
low-level jet, so a relatively short period of Advisory level winds
is likely as this front moves through. The strongest gusts of 40-45
knots will likely occur between 16 and 20Z before diminishing rather
quickly as the dynamics shift east. Ended the advisory west of I-71
at 21Z, but ran it through 00Z along the lakeshore from Lake County
to Erie County, PA where westerly winds off the lake behind the
front will be slower to subside, and pattern recognition also
supports this.
Regarding other impacts with the system, the precip will be far less
impactful than the winds. As mentioned above, warm air advection and
isentropic ascent will push a band of light precip across the region
ahead of the warm front Thursday morning into early afternoon.
Thermal profiles suggest that this will start as a brief rain/snow
mix, especially in northern and eastern areas, before switching to
all rain. Drier air in the mid-levels will quickly filter in with
the trailing cold front Thursday afternoon, so expect precip to cut
off rather quickly. In fact, some areas may not see more than
sprinkles from the entire system, with maximum QPF only reaching a
couple of tenths in far NE Ohio and NW PA. This drier air advection
will help with the mixing and get the gusty winds going with the
cold frontal passage, so all in all, this will be a windy but fairly
dry system. Cold air advection and NW flow Thursday night with 850
mb temps dropping to -11 to -13 C will support multiple bands of
weak lake-effect snow showers in NE Ohio and NW PA, so kept slight
chance to chance PoPs through the night in these primary snowbelt
areas. Weak overall instability and dry air, combined with
increasing boundary layer shear ahead of shortwave ridging quickly
building eastward, will keep accumulations at a trace to up to 0.2
inches at most over the higher elevations of NE Ohio and NW PA.
Highs Thursday will warm into the mid/upper 40s, with lows Thursday
night dropping back into the mid/upper 20s.
&&
.SHORT TERM /6 PM THURSDAY EVENING THROUGH SATURDAY NIGHT/...
A wintry period for the start of the weekend is expected as a deep
upper trough develops over eastern Canada and the northeast states.
A weak short wave will cross the Ohio valley on Friday and spread
light snow mainly across the southern counties near US Route 30.
Accumulations will be minimal. After the short wave departs to the
east, a rather cold westerly flow will develop as 850 mb
temperatures drop to the -12 to -16C range with the surface based
inversion height rising to 6000` to perhaps 10K feet height briefly
near ERI. So we can expect lake effect snow showers to develop and
move into the snowbelt from Cleveland east into NY state.
A plowable LES snowfall is possible.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
Deep trough over the eastern Canada will relax during the period and
the upper flow will become more zonal. A rather strong clipper
system will move into the northern lakes on Sunday as it passes to
the north and east of the region. A trailing cold front will cross
the area Sunday night with a push of polar air behind along with a
few lake induced snow showers. High pressure will build into the
region on Monday and shift east of the area on Tuesday. A weak
system/short wave will move across the area on Tuesday but mild
temperatures will keep precipitation as liquid. The region will
remain in a broad warm sector for Wednesday with generally dry
conditions expected and above normal temperatures.
&&
.AVIATION /00Z Thursday THROUGH Monday/...
VFR across the area this evening and overnight with
deterioration to widespread MVFR and perhaps brief IFR expected by
Thursday afternoon. A strong low pressure system will move
northeast across the Central Great Lakes on Thursday, extending
a cold front east through the area. An area of moderate to
perhaps heavy rain will coincide with the front and could drop
vsbys briefly to IFR. Otherwise, primarily MVFR ceilings will
exist with perhaps even improvement to VFR towards the end of
the TAF period across NW OH.
Winds will be light and variable overnight and into Thursday
morning. Winds will increase out of the south, 10 to 15 knots
with gusts of 20 to 25 knots possible by mid-Thursday morning.
As a cold front moves east across the area, winds will abruptly
shift towards the southwest and could initially gust 35 to 40
knots at all TAF sites with the rain/front. Behind the front,
winds will gradually shift more towards the west, remaining
elevated in the 20 to 25 knot range with gusts of 30 to 35 knots
and perhaps brief periods of 40 knots at times through the
afternoon.
Since winds should be elevated for the most part through the TAF
period, did not include any mention of LLWS at this time.
However, cannot rule out some southwesterly LLWS across NW OH
early Thursday morning before the more elevated surface winds
arrive.
Outlook...Non-VFR possible in light rain/snow showers Thursday
night across NE OH and NW PA. Additional non- VFR may be
possible with scattered light lake effect snow showers Friday
into Saturday, mainly for the snowbelt areas downwind of Lake
Erie.
&&
.MARINE...
Light winds will prevail over Lake Erie tonight as High pressure
over the lake moves to the east and allows a southeasterly flow to
develop. Meanwhile low pressure over the Central Plains will develop
and move to near Chicago by morning. The low will track just north
of Lake Erie on Thursday and off the New England coast on Friday.
Strong west winds will develop Thursday afternoon and persist into
Thursday night which will require a Gale warning from Willowick
(LEZ147 and LEZ167) and points east from Thursday afternoon until
after midnight near 06Z. Winds will diminish and veer to the
northwest by Friday morning. High pressure will gradually build into
the region on Saturday which will be followed by a clipper system on
Sunday. Southwest winds will increase Sunday ahead of a cold front
to 20-30 knots. A cold front will cross the lake Sunday night as
high pressure builds into the region on Monday.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Wind Advisory from 11 AM to 4 PM EST Thursday for OHZ003-
006>011-017>020-027>030.
Wind Advisory from 11 AM to 7 PM EST Thursday for OHZ012-089.
PA...Wind Advisory from 11 AM to 7 PM EST Thursday for PAZ001.
MARINE...Gale Warning from 3 PM Thursday to 1 AM EST Friday for
LEZ147>149-167>169.
&&
$$
SYNOPSIS...Garuckas
NEAR TERM...Garuckas/Kahn
SHORT TERM...LaPlante
LONG TERM...LaPlante
AVIATION...Kahn
MARINE...LaPlante
Area Forecast Discussion
National Weather Service Des Moines IA
544 PM CST Wed Feb 14 2024
...Updated for the 00z Aviation Discussion...
.KEY MESSAGES...
* Rain and snow return to the area tonight - Best accumulating snow
chances remain far north. Mainly rain elsewhere.
* Second quick shot of precipitation (all snow) Thursday
evening/night into early Friday - Potential for an area/band of 2+
inches.
* Short stint of colder (seasonable) temperatures Thursday
through Saturday, then warming back well above normal rest of
forecast.
&&
.DISCUSSION...
Issued at 237 PM CST Wed Feb 14 2024
Conditions remained quiet through the day today as the system
continues to slowly build into the area. Sensible weather wise, it
has primarily been mid to high level cloud cover streaming overhead
in conjunction with southerly to southeasterly winds boosting
temperatures into the 50s in many location. The quiet and warmth
will come to an end this evening and overnight.
Broadly, hi-res guidance remains in fair to good agreement on the
placement of accumulating snowfall being along and north of the Iowa-
Minnesota border. Where there have been some recent changes,
including the strength and placement of anticipated banded
precipitation. Such as recent HRRR runs have suggested less
strength/prominent banding in the 850-700mb layer and more
strength/prominent banding in the 925-850mb layer. As it pertains to
the CWA, it is primarily a shift northward of the southern QPF band
and a bit of an uptick in QPF, now across the northern couple of
tiers of Iowa. Fortunately, near-surface temperatures remain such
that rain remains the primary result within this area. A semi-
widespread area of about a quarter inch or greater may be
experienced as a result. Localized amounts of a half inch would not
be out of the question either. On the accumulating snow side of
things, as hinted above, hi-res guidance remains largely right along
and north of the Iowa-Minnesota border for around an inch or two of
accumulating snow, and higher banded snowfall amounts about a tier
of counties into Minnesota. Northern neighbors have understandably
issued Advisory headlines. While none are out or expected for the
CWA, it is not out of the question a short one may be need in/along
the northern most tier of Iowa should there be a subtle southward
shift.
As additional surge of moisture/theta-e advection comes in on the
LLJ, a few convective elements remain likely in central to southern
areas along/ahead of the surface front. Pick your CAM, they all
predominantly show this opportunity. Nothing substantial here, than
a possible rumble of thunder or two and a quick tenth to quarter
inch of rain or so.
Maybe more notable for many will be the breezy north winds on the
heels of this system ushering in colder temperatures more in line
with mid-February. More on this in a minute though.
A second quick shot at precipitation will slide thorugh large scale
pattern Thursday evening and overnight. Given the aforementioned
colder temperatures, this will be all snow. The most notable change
over the last 24 hours or so with this round have been the
appearance of some mid-level banding. While not as
strong/significant as the first system, this does degrade some
confidence in locations of highest snowfall with most recent trends
pushing it form roughly a line from Spencer-Fort Dodge-Marshalltown
southward a row of counties or two. Within the banded area, the
potential for 2 to 4 inches of snow remains, with a broader area of
lesser amounts. This activity will largely be overnight Thursday
into Friday, and out of the area by mid-late morning. No headlines
have been hoisted locally due to continued shifts within guidance of
the banded area, but do anticipate one will be hoisted overnight
tonight or during the daytime Thursday.
Back on temperatures, expect more seasonable conditions Thursday
through Saturday as large scale troughing/NW flow settles in. This
will be fairly brief though, as height rises and more zonal flow
returns by Sunday and well into next week, resulting in highs rising
back into the 50s. Quiet conditions will largely prevail through the
weekend and into next week.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 544 PM CST Wed Feb 14 2024
Conditions will deteriorate quickly this evening with
precipitation developing and overspread much of the northern
half of Iowa. Initially much of it will be rain with transition
to snow on the northwest backside of the precipitation. VFR
conditions are expected to become MVFR to IFR by 06Z and remain
there overnight. However, clearing is expected on Thursday
morning with VFR conditions returning for much of the daytime.
Surface winds become northwest across all of Iowa tonight and
increase rapidly behind the system. The northwest winds continue
into Thursday and gradually decrease.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
DISCUSSION...Curtis
AVIATION...Cogil
Area Forecast Discussion
National Weather Service Grand Rapids MI
943 PM EST Wed Feb 14 2024
.KEY MESSAGES...
- Impactful Snow for the Thursday Morning Commute
- Colder with lake effect snow showers this weekend
- Moderating temperatures early next week with rain and snow
chances
&&
.UPDATE...
Issued at 943 PM EST Wed Feb 14 2024
Forecast remains largely on track with a quick burst of snow
expected to impact the Thursday morning commute.
There will be an ample amount of low to mid level frontogenesis
along with convergence from the low level jet mainly between
4 AM to 10 AM Thursday morning. This will bring the potential
for 1 inch per hour or greater snowfall rates with the better
rates north of the I-96 corridor. The track of the overall low
and how much warm air is advected into the region will determine
where the rain/snow line sets up. At this time the transition
looks to be just south of I-96, but there are hints it could
push farther south and therefore bring slightly higher
accumulations along I-96. This can be seen more so in the spread
of the 10th to 90th percentile where the 10th is little to no
accumulation and the 90th has mainly 1.5 to 4 inches of snow
from the Lansing area to Muskegon. We`ll continue to monitor
trends overnight as the system moves into Wisconsin, those in
the transition zone and a little farther south keep an eye for
slight changes in the forecast as we head into Thursday morning.
&&
.DISCUSSION...
Issued at 321 PM EST Wed Feb 14 2024
- Impactful Snow for the Thursday Morning Commute
This next wave of low pressure has multiple features that support a
burst of heavier snow for parts of the the area. Stronger FGEN,
negative tilted mid level wave, steep mid level lapse rates and even
some instability. It`s interesting to see such high probabilities
for 1 and even 2 inch per hour snow rates on the SPC HREF`s page.
The 15z RAP just came in with 700-500 mb lapse rates of 8 deg C.
This will be a quick hitting system, likely lasting 6 hours or less
with the steadiest snow. The main window for the deeper moisture
and lift is shown to be 11z to 17z. Thus, the morning commute will
likely be impacted where the higher snow rates occur. Complicating
the forecast will be an elevated warm layer that lifts up from
the south and surface temperatures will be rising above the
freezing mark. Most indications are that the northward movement
of the warm layer will stall out just north of I-96 Thursday
morning. The location of this warm layer could change, so we
will need to monitor the trends as the system nears. This
scenario would support snow changing to mixed precipitation or
just plain rain for the cities of Muskegon, Grand Rapids and
Lansing. Considering the system will be occurring during the
morning commute and will likely feature a period of heavier snow
rates at that time, we will go with a headline, even for those
areas expected to see less than 3 inches. As a result, we are
looking at a winter weather advisory for roughly the northern
half of the CWA. We will have two segments. The southern group
including Grand Rapids, Muskegon and Lansing and this group will
feature less snow than areas further north because of the
potential for the snow to mixed with other precipitation types.
Looking upstream there are plenty of stations reporting quarter
mile vsby`s in SD and parts of NE which adds confidence that we
will see impacts for parts of our area when the system arrives.
- Colder with lake effect snow showers this weekend
In the wake of the system coming through on Thursday, we will see
colder air filter into the area from the North. The core of this
blast of colder air will be over the area from Friday night into
Saturday. 850 mb temps are expected to fall to almost -20C,
something we have not seen around here recently. This colder air,
combined with the upper jet core sinking south of the area will
allow for a short period of some lake effect snow showers that
could accumulate.
The jet core will only be in a favorable position over the area
until Saturday afternoon, before the upper flow becomes anti-
cyclonic once again. Lake effect will continue into Sunday, but it
should not be very impactful with a shallow cloud layer at that
time. The lake effect snow showers will taper off on Sunday as
ridging builds in.
- Moderating temperatures early next week with rain and snow chances
The cold air will be on the moderating trend then for early next
week. The upper trough will have moved out, and high pressure at the
sfc will slip east of the area. This will allow for return flow to
dislodge the cold air mass, and bring in some warmer temperatures.
The SW flow will continue at the lower levels, and will continue to
bring warmer temperatures up and over the area. The ensemble means
are showing max temps in the 40s as early as Sunday, and more likely
by Monday. Then, it looks like we could see some 50s once again with
strong ensemble support with the conveyor belt of warm air coming
in. Eventually, around the Tuesday/Wednesday time frame, we will see
the front driving this warm air up into the area approach. This will
bring increased precipitation chances, mostly in the form of rain.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 625 PM EST Wed Feb 14 2024
VFR conditions are expected until a quick burst of snow and rain
moves through the area mainly between 9Z-16Z Thursday morning.
Areas along and north of a MKG to GRR to LAN line have the best
potential for accumulating snow with snowfall rates up to an
inch per hour. South of this line there is the better chance for
rain, surface temperatures will initially be marginal and could
result in a brief period of light icing before temperatures warm
more. There is still some uncertainty in the transition zone
from snow to rain and a slight shift will impact precipitation
types mainly for the MKG to GRR to LAN line. IFR to MVFR
ceilings and visibilities are expected with the potential for
LIFR visibilities in any heavier snow. Precipitation shifts east
of the area by Thursday afternoon with lingering MVFR ceilings.
Gusty winds are also expected with the snow with gusts 20 to 30
knots initially from the south and then shifting to the
northwest as precipitation exits. Low level wind shear will also
be present mainly along the AZO to JXN line during the morning
hours.
&&
.MARINE...
Issued at 943 PM EST Wed Feb 14 2024
Southerly winds and waves build Thursday morning bringing a
brief period of Small Craft Advisory conditions before northwest
gales develop on the backside of the low mainly south of
Pentwater. Gusty northwest winds and high waves continue before
subsiding Thursday night into Friday.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Winter Weather Advisory from 4 AM to 11 AM EST Thursday for
MIZ037>040-043>046-050>052-056>059-066-067.
MARINE...Gale Warning from 9 AM to 5 PM EST Thursday for LMZ844>848.
Small Craft Advisory from 9 AM to 5 PM EST Thursday for LMZ849.
&&
$$
UPDATE...
DISCUSSION...MJS/NJJ
AVIATION...RAH
MARINE...RAH
Area Forecast Discussion
National Weather Service Gray ME
1046 PM EST Wed Feb 14 2024
.SYNOPSIS...
Windy conditions persist into this evening before slowly
diminishing tonight into Thursday. A weak low pressure will then
bring light snow to the region Thursday night into Friday. Once
this system exits Friday morning, breezy conditions will
continue through the day on Friday. A couple of weak
disturbances will allow for more scattered snow showers over
the weekend, but mostly dry conditions are expected for early
next week as high pressure starts to build in.
&&
.NEAR TERM /OVERNIGHT/...
1045 PM Update...Little change to the going forecast with just
another round of tweaks with 00Z data coming in. Still a bit
gusty out there, however by this time gusts are generally below
30 mph.
645 PM Update...Performed a general refresh of the forecast
through the overnight hours using latest hires guidance...
focusing mainly on wind trends, as well as PoP trends across the
north. Overall no drastic changes, although stronger wind gusts
may take a touch longer to diminish through late evening. Hires
guidance hints that a lowering of the top of the mixed layer
may tend to concentrate gusts around terrain until high pressure
builds in tomorrow.
Previously...
A very blustery day continues into the evening. While mixing is
set to slowly decline through the evening, trough on the
backside of the passing mid-level low will keep winds around.
850 mb winds look to increase to around 50 kts as mixing begins
to subside. Can’t rule out a few gusts continuing in the 35 to
45 mph range through 6 or 7pm before trending below 25 mph after
midnight. Mostly clear skies are expected tonight, but wind
will keep the area from decoupling substantially. Lows fall into
the teens across the interior and coast, with single digits
above zero through out the mountains/valleys. Moisture lingers
over the mountain until after midnight, and believe the chance
of snow showers tapers thereafter.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
Thursday will feature dry conditions, rebounding temperatures,
and lighter winds. This is amid good sun and west winds where
temps push into the mid 30s across the interior and mid 20s for
mountains. Clouds increase through the day, beginning with high
cirrus, and becoming lower stratus by late afternoon. Low
pressure will be advancing, with snow, from the Great Lakes into
the evening and overnight hours.
For snow on Thursday night, not a whole lot of difference in
timing. Some discrepancy on onset, as dry air will be last to
leave the very low levels. Can’t rule out some flakes beginning
around 6 or 7pm in western NH, but main accumulating snow begins
later in the evening. QPF wise, the HRRR is the standout that
produces about a tenth to two tenths more liquid than other
hires models. Will keep sided with remainder of HREF members for
now. But will still need to pay attention to any convergence
bands that linger and train over an area. These formations will
be favorable considering the tilt and direction of the exiting
low. A concentrated band could provide an addition 2 or 3 inches
early Fri morning compared to surrounding locales, but at the
moment there is a wide range of where this could form: from
southern NH towards the Midcoast of ME. Ratios still look high,
resulting in fluffy snow amid a healthy DGZ. Isentropic analysis
hints at dry air sweeping into southern NH between midnight and
daybreak Friday, resulting in poorer snow growth here, but may
still result in slick travel in the AM due to warm front snow on
the front side. End result here would be reduced rates in
southern NH to York Co. A widespread 2 to 4 inch snow event
seems likely. A corridor from the Whites towards the ME Midcoast
and perhaps as far south as Casco Bay and the northern York
coast is the general area where additional accums may result due
to aforementioned convergence. This is where inverted trough
tries to hang on as the low/occlusion becomes more elongated
east-west. Unchanged is snow character, which is expected to
remain lighter and on the fluffy side.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Models are in good agreement showing the center of the low
pressure over the Gulf of Maine around daybreak Friday. This low
will continue moving off to the east, resulting in any
lingering light snowfall to taper off through the morning hours.
For the rest of the day, it should be a mix of sun and clouds
(outside of the mountains) and chilly as cold advection and
breezy northwest winds kick in. Forecast soundings support wind
gusts of 25 to 35 mph through the afternoon keeping wind chills
in the teens. With the recently fallen dry/fluffy snow Thursday
night, this could result in some blowing snow. Upslope snow
showers will persist in the mountains with upslope flow, and
high Froude numbers suggest some of these could spill over the
mountains along with more cloud cover.
Longwave troughing more or less remains near the Hudson/James
Bay this weekend with multiple weak shortwaves crossing New
England. So we`ll have a couple more opportunities for light
snow showers with the first being on Saturday and the other
being late in the day Sunday or into Sunday night. Ensembles
from the GFS/ECMWF are in good agreement with little in the way
of accumulation at this time.
Outside of upslope snow showers in the mountains on Monday, the
start of next week looks mainly dry as the upper air pattern
becomes briefly becomes more zonal. Temperatures may climb back
into the 40s over parts of the area Monday and Tuesday before
another weak shortwave trough approaches around next Wednesday.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
Short Term...NW gusts to 35 kts continue this evening, tapering
to around 25 kt after midnight. Some gusts to 45 kt will be
possible early this evening, but these are expected to be
isolated. Some LLWS may result as surface mixing diminishes, but
elevated jet lingers before exiting to SE. Otherwise, VFR
conditions with MVFR vis at times in the mountains with light
snow. VFR Thursday with increasing cirrus. MVFR ceilings are
likely overnight into Friday morning, with areas of IFR. Vis is
expected to be impacted due to moderate snow rates overnight.
Improvement is expected Friday afternoon first across southern
NH terminals, and then coastal/interior sites of ME.
Long Term...Light snow could continue to reduce visibilities at
RKD and AUG through late Friday morning along with MVFR
ceilings. HIE and LEB could see MVFR ceilings along with snow
showers in the vicinity through the day. VFR elsewhere.
Northwest winds will be gusty on Friday on the order of 25-30
kt, possible 30 kt on occasion, but these will die off Friday
evening and into Friday night. Mainly VFR (except HIE) through
the weekend, but a couple of weak systems could bring brief
restrictions on Saturday and again Sunday night.
&&
.MARINE...
Short Term...Gale conditions continue through today, becoming
SCA Thursday morning. Winds to 45 kts can be expected early
this evening and overnight, steadily decreasing after midnight.
Light freezing spray is expected tonight through Thurs morning
with the cool air, gusty winds, and wave action. Waves become 2
to 4 ft Thursday afternoon as brief ridging crosses the waters
and winds fall below SCA. Next low pressure will quickly advance
and pass over Thursday night. Winds here should generally
remain below Gale force, but winds to 30 kts will be possible
for the southern waters off NH and far southern ME. Winds become
WNW Friday morning as the low passes into the Gulf of Maine.
These gusts remain through the day.
Long Term...Low pressure will be traveling across the Gulf of
Maine Friday morning, and it`s possible there could be a brief
period of gales, but for the most part northwest winds are
expected to gust to 25 to 30 kt through the day on Friday,
maintaining SCA conditions into at least Friday evening. Winds
further diminish through Saturday before increasing again on
Sunday as another weak low pressure quickly moves across
northern New England from west to east Sunday night. This is
probably bring more SCA conditions that could last into Sunday
night or Monday before high pressure brings improvement by
around Tuesday or so.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Gale Warning until 7 AM EST Thursday for ANZ150>154.
&&
$$
UPDATE...Casey
NEAR/SHORT TERM...Cornwell
LONG TERM...Combs
Area Forecast Discussion
National Weather Service Marquette MI
1012 PM EST Wed Feb 14 2024
.KEY MESSAGES...
-After a brief dry period with partially clearing skies for the
early evening, another round of widespread snow moves in from
the south.
-Heavier embedded banding may lead to snowfall rates up to an
inch per hour across the southeast UP late tonight into
Thursday morning.
-A Winter Weather Advisory is in effect for much of the eastern
UP.
-Nearly continuous lake effect snow chances from Thursday
through Sunday, mainly for NW wind snow belts. LES will be
periodically enhanced by passing disturbances that also shift
wind direction.
&&
.UPDATE...
Issued at 1011 PM EST Wed Feb 14 2024
Watching the band of moderate to heavy snow upstream over
central/eastern MN tied to a good 700 mb Fgen signal. Most guidance
was too far south with this band, with the 00Z RAP/HRRR appearing to
have the best handle on it. However, this guidance also has this
forcing washing out a bit with eastward extent. Incorporated some of
this guidance with an update which raises snowfall totals slightly
over parts of Gogebic/Iron/Dickinson more solidly in the 2-4" range.
Another area of Fgen a bit lower in the column is expected to evolve
for the Lake Michigan shoreline counties in the 06-12Z frame, with
00Z HREF guidance showing potential for 0.5-0.75"/hr rates (perhaps
briefly up to 1"/hr at times). Ahead of this band, light snow has
begun in the Wisconsin border counties.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 242 PM EST Wed Feb 14 2024
This afternoon, RAP analyses show low pressure moving into western
Ontario with another over the southern Plains. Flurries and snow
showers associated with an earlier warm frontal passage are moving
out of the eastern UP, and breaks in the clouds are developing
across the western half of the UP with more clearing across NW WI.
However, with another surge of WAA ahead of the Plains system, mid
and upper level clouds are already spreading into eastern MN. Thus,
clearing should be fairly short-lived this evening.
Our brief dry period comes to an end heading into the late evening.
Snow is already spreading into southern MN courtesy of strengthening
isentropic ascent ahead of the Plains low. IR and water vapor
imagery show a narrower band of cooler cloud tops draped over south-
central MN, in an area of more robust frontogenetical forcing.
Tonight, as the Plains low continues to track northeast towards the
Great Lakes, widespread light snow spreads into the UP. Amid
tightening 850-700mb frontogenesis, embedded heavier snowfall
banding is looking likely to at least graze the southern UP.
Simulated reflectivity courtesy of the CAMS, show widespread light
snow with heavier banding extending from Menominee to southern Luce
counties. HREF ensemble guidance indicates snowfall rates generally
around a quarter to half inch per hour across most of the UP, and
heavier rates potentially up to an inch per hour in those heavier
bands (40% chance). Southerly flow off of Lake Michigan could also
contribute to locally higher snowfall rates from southern
Schoolcraft to southern Luce counties. That said, though guidance is
favoring the southeast UP, one thing to watch out for will be any
potential for heavier banding to expand more northward - which could
put Dickinson and southern Marquette counties in the line of fire as
well.
The period of heaviest snowfall rates looks to be from around 06-
12Z, but some ensemble members still favor heavy banding through the
late morning; as this encompasses basically the entire morning
commute, a Winter Weather Advisory is in effect, and will be
extended to include Menominee and Delta counties. Meanwhile, the
western UP, and especially the Keweenaw, could miss out almost
entirely on any snowfall until lake effect snow kicks off behind the
exiting system. This should leave us with a widespread 1-3in of snow
across the central UP by tomorrow morning, with lighter amounts
below an inch to the west. Higher totals generally around 3-5in are
expected across the eastern UP.
Otherwise, with a warmer airmass moving in and clouds filling back
in, expect temperatures to stay much warmer tonight than last night;
lows range in the 20s area-wide.
&&
.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
Issued at 310 PM EST Wed Feb 14 2024
By Thursday morning, both the cold front and surface low pressure to
the south will have phased into a single system around 1005mb over
Lake Huron and will be rapidly exiting the region. Aloft, anomalous
ridging will be over Alaska and NW Canada with mainly flat zonal
flow across the CONUS, though the ridge will help force some
shortwaves through the Upper Great Lakes Thursday and Friday. Into
the weekend and beyond, the pattern over the CONUS amplifies as
anomalous troughing builds over the Upper Great Lakes, with the
ridging to the west weakening slightly over the Rockies, and a deep
trough approaching the West Coast.
Synoptic snowfall shifts east midday Thursday with northwesterly
lake effect snow showers breaking out. By 850mb temperatures, the
HREF mainly agrees that sufficiently cold temperatures aloft will
already be in place by 12Z Thursday in the west with the east
following by noon local time. RAP soundings show a fairly impressive
LES environment developing as synoptic snow ends with inversions to
near if not above 10kft Thursday afternoon and evening with
saturated DGZ depths of over 3 kft. The only hi-res model that
delays NWerly LES bands is the Canadian hi-res, which only delays
formation by a couple of hours after the cessation of synoptic
precipitation. Cold air advection continues through Saturday morning
when delta-T values approach 25C implying high-end LES PoPs are
needed well into the weekend. An upper level trough moves across the
area on Friday, bringing some NNWerly and Nerly flair to the LES
bands for a time Friday afternoon/night. A surface ridge axis
crosses the lake late Friday night into Saturday with winds shifting
Werly and SWerly on Saturday. Lake effect snow showers will continue
despite the ridging due to the strong thermodynamic profile for LES,
though much of the impacts may lift offshore in SW wind regimes.
Winds veer northwesterly again late Saturday night or Sunday as one
or two energetic clipper systems track across the region. The 12Z
GEFS shows a small cluster of 1000s mb lows passing through Lake
Superior as soon as Saturday morning, but more likely is a passage
of an approximately 1000mb low overnight Saturday into Sunday. The
12Z GEFS has some considerable spread however, with low tracks as
far south as the Straits of Mackinaw and as far north as the shores
of the Hudson Bay. Substantial lake enhancement is possible
depending on their tracks, especially across the east where a longer
fetch and higher probabilities of supportive 850 mb temps exist.
Beyond the weekend, the pattern becomes somewhat ill-defined in the
early-week, but ensembles are starting to hone in on a weak low
lifting out of the Plains late Monday into Tuesday and then a
stronger Colorado Low-type system in the Thursday to Friday time
frame, though spread is quite high, so forecaster confidence is low.
The temperature pattern is a bit tricky, as disturbances within the
zonal flow could have the UP flipping quickly between a polar air
mass and a Pacific air mass. In general, near normal temperatures
should prevail but the eastern UP has a better chance at below
normal temperatures whereas the western UP has a better chance for
above normal temperatures.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 642 PM EST Wed Feb 14 2024
Quick-hitting low pressure system will bring snow to IWD/SAW
tonight, mainly 03-08Z for IWD and 06-13Z for SAW. Relatively high
confidence (80%) in IFR vsby at SAW, and moderate (50%) at IWD
during this timeframe. Moderate confidence (40%) in LIFR vsby at SAW
depending on how far north heavier snow bands move. Cigs are also
likely to fall to IFR eventually at SAW. The snow is expected to
remain south of CMX with MVFR cigs developing and likely no impact
to vsby. Conditions improve to MVFR behind the system late tonight
into Thursday morning, potentially with lingering lake effect snow
showers at IWD/CMX.
&&
.MARINE...
Issued at 310 PM EST Wed Feb 14 2024
Southwesterly to westerly gusts up to 20-25kts are ongoing this
evening, veering northwest as a low pressure tracks across northern
Ontario and sends a cold front across the lake tonight. Winds
increase to around 30 kts behind the front Thursday morning before
increasing to 35-40 kt gales across the eastern lake Thursday
afternoon and evening. In addition to gales, we will see moderate to
locally heavy freezing spray return across the lake from Thursday
afternoon through Friday morning. Northwest winds decrease to around
20-25 kts for Friday with another cold front increasing NW winds to
around 30 kts Friday night, mainly in the nearshore waters. A low
pressure tracking near Lake Superior brings renewed gale potential
this weekend with southwest winds ahead of the low and northwest
behind. Gale probabilities are about 30% in the west half of the
lake Saturday and around 45% in the east half on Sunday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Winter Weather Advisory from 3 AM to 1 PM EST Thursday for
MIZ007-014-085.
Winter Weather Advisory until 10 AM EST /9 AM CST/ Thursday
for MIZ012-013.
Lake Superior...
Small Craft Advisory from 7 AM EST /6 AM CST/ Thursday to 7 AM
EST /6 AM CST/ Friday for LSZ240>242.
Small Craft Advisory until 1 AM EST Thursday for LSZ242.
Small Craft Advisory until 7 AM EST Friday for LSZ243-244.
Small Craft Advisory from 10 AM Thursday to 7 AM EST Friday
for LSZ245.
Small Craft Advisory from 10 AM to 7 PM EST Thursday for
LSZ246-247.
Small Craft Advisory from 7 AM Thursday to 10 AM EST Friday
for LSZ248.
Small Craft Advisory from 7 AM to 1 PM EST Thursday for
LSZ249>251.
Gale Warning from 1 PM Thursday to 1 AM EST Friday for
LSZ249>251-266-267.
Lake Michigan...
Small Craft Advisory from 1 PM Thursday to 1 AM EST Friday for
LMZ221.
Small Craft Advisory until 1 AM EST Friday for LMZ248-250.
&&
$$
UPDATE...Thompson
SHORT TERM...LC
LONG TERM...EK/GS
AVIATION...Thompson
MARINE...EK/GS
Area Forecast Discussion
National Weather Service Pueblo CO
843 PM MST Wed Feb 14 2024
.KEY MESSAGES...
- Mostly quiet weather expected for the rest of tonight and
tomorrow, with light mountain snow showers continuing across
portions of the Continental Divide
- Better chances for snow move in for Friday and Saturday, to
include light accumulations possible over portions of our
mountain adjacent plains.
- A trend towards warmer and drier weather kicks off Sunday and
persists through at least the middle of next week.
&&
.UPDATE...
Issued at 841 PM MST Wed Feb 14 2024
Quick update to the forecast grids for a slight increase in
cloud cover over the far eastern plains tonight into Thursday.
Latest satellite imagery shows the stratus shield moving in at a
quicker pace. Also brought in latest obs data, as well as HRRR
and RAP13 model data.
&&
.SHORT TERM /THROUGH THURSDAY/...
Issued at 247 PM MST Wed Feb 14 2024
Currently..
Satellite imagery shows weak shortwave energy traversing the region,
with increasing cloud cover over the high country. MRMS shows light
snow showers over the Continental Divide, mainly over the
central mountains. Northwest winds have increased over the
region as well, with westerlies gusting to around 30mph across
much of our mountain adjacent plains. Temperatures have risen
into the 40s and 50s for most locations.
Tonight and Tomorrow..
Overnight lows are looking to stay just a couple of degrees above
normal for most locations tonight, with the help of increasing
westerly flow and mid and upper-level cloud cover. Lower
elevations look to cool into mid 20s, with teens over mountain
valleys and higher terrain locations. Zonal flow returns
tomorrow, which will help to keep most areas dry and mostly
sunny for tomorrow afternoon. Breezy westerly and southwesterly
winds look to return, with gusts up to 50 mph over the highest
peaks of the central mountains, up 40 mph over the rest of the
high country, and gusts up 30 mph across portions of our
mountain adjacent plains and the San Luis Valley. Daytime highs
are looking to be above normal again, with lee troughing
developing over our plains, allowing them to warm well into the
mid 50s. Mid 40s are expected for mountain valleys, with 20s and
30s for higher terrain locations. Models depict another bout of
weak shortwave energy traversing the area Thursday night into
Friday, which will allow for another round of light show showers
over portions of the Continental Divide. Accumulations look to
be minimal, with highest amounts over our central mountains,
where generally 4 inches or less of new snowfall is expected by
early Friday afternoon.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Issued at 247 PM MST Wed Feb 14 2024
Friday and Saturday..
Models bring a cold front south across our plains Friday morning,
with shallow upslope flow developing behind it throughout the day
and into the overnight hours of Friday. This will keep daytime highs
on Friday about 10 to 15 degrees cooler than what we`re expecting
for Thursday. Snow showers should hold off through much of the day
on Friday, as upslope slowly increases over the area. Model guidance
suggests that we could see snow showers over the Palmer as
early as the evening commute, though any daytime accumulations
will likely be minimal, as temperatures look to stay fairly warm
throughout the event. Overnight Friday and into early Saturday
looks to be the most likely window for any accumulating
snowfall, with the Pikes Peak region seeing at least an inch or
two of new snow overnight. Other areas that could see light
accumulations include the Wet Mountains, the Sangres, and
possibly portions of the southern I-25 corridor.
Sunday Onwards..
Messy ridging tries to build in for Sunday onwards, though embedded
shortwave energy may keep snow chances over the high country for
both Sunday and Monday. There`s not a lot of model agreement in
regards to these features quite yet, but it does seem likely that
lower elevation locations should begin to see warmer and drier
conditions from Sunday onwards. High temperatures through at least
the middle of next week look to remain above normal for most
locations.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 247 PM MST Wed Feb 14 2024
VFR conditions are expected at all three TAF sites, KCOS, KPUB, and
KALS for the next 24 hours. Scattered mid and upper-level cloud
cover is expected off and over over all three stations throughout
the period. Northwesterly winds gusting up to 25kt look to continue
though the rest of this afternoon, especially at KPUB and KALS.
Winds become more southwesterly tomorrow. Precipitation is not
expected on or near any of our stations.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...MOORE
SHORT TERM...EHR
LONG TERM...EHR
AVIATION...EHR
Area Forecast Discussion
National Weather Service Topeka KS
546 PM CST Wed Feb 14 2024
.KEY MESSAGES...
-Cold front moves through tonight, with some sprinkles possible.
-Light snow could then occur early Friday as another quick
moving system moves over the area.
-Temperatures remain cool to start the weekend before the next
warm early next week.
&&
.DISCUSSION...
Issued at 206 PM CST Wed Feb 14 2024
It`s a warm and breezy Valentine`s Day this year! By 19Z today,
temperatures had warmed into the 60s with strong southerly flow
ahead of surface low pressure centered in southwestern KS. Mid and
high level cloud cover will increase late this afternoon and this
evening as a shortwave trough approaches the area from the west.
Models shows a small amount of elevated instability developing
ahead of the surface low as it moves northeast across the state this
evening. A lack of deep moisture will likely inhibit much in
the way of rain development, but have included sprinkles across
eastern KS as an associated cold front moves through the CWA.
Winds will shift to the northwest behind the front tonight.
Tomorrow will be cooler as high pressure builds in from the north.
High temps are forecast to range from the mid 40s in northern
KS to near 50 degrees near and south of Interstate 70. Our next
quick moving shortwave within zonal flow aloft will approach the
area Thursday night and early Friday. Models still don`t show
great agreement on where precipitation will occur across the
region, but there is enough of a signal to continue with 30-40%
chance POPs in the forecast area Friday morning. The
temperature profile will mainly be below freezing, supporting a
chance for snow, or perhaps some drizzle depending on how
deeply saturated the column can remain. A few slick spots may
result until temperatures warm above freezing by midday. A
dusting of snow could also accumulate, mainly on grassy and
elevated surfaces.
Northwest flow behind a more amplified troughing pattern will keep
conditions chilly to start the weekend before our next warming
trends commences on Sunday with the return of low level southerly
flow. Dry conditions are also expected through the weekend.
Long range deterministic models hint at another mid level wave
impacting the central US early next week, which could bring
some light QPF back to the forecast at that time.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 546 PM CST Wed Feb 14 2024
Cold front associated with upper level trough brings varied
concerns. Winds will shift to the northwest around 06Z, looking
a bit earlier than previous expectations. High-based showers
are possible through around 06Z but if they do pass over the
terminals they would have very limited impacts. Concern is
rising for MVFR ceilings to form behind the front. The RAP is
the most pessimistic with the ceilings` timing and longevity but
it was the best at handling shallow stratus so have included a
TEMPO group shortly behind the front at this point.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Teefey
AVIATION...65