Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/30/24
Area Forecast Discussion
National Weather Service La Crosse WI
549 PM CST Fri Nov 29 2024
.KEY MESSAGES...
- Cold & dry for much of this weekend with flurries exiting the
area today. Wind chills during the morning hours this weekend
will be between 0 and 10 degrees below zero and only
recovering into the single digits during the afternoon.
- Conditions remain cool and dry until Tuesday night with
precipitation chances (20-50%) returning to the area and a
brief return to seasonable conditions with highs in the 30s
for Wednesday.
&&
.DISCUSSION...
Issued at 132 PM CST Fri Nov 29 2024
Rest of Today - Tuesday: Cold, Dry with Lingering Flurries
Broad troughing over the eastern CONUS today continues to remain the
key feature synoptically as a fairly robust continental polar
airmass remains in place across the region for today and through the
weekend. As we continue through much of the day, an axis of dry air
noted on GOES-16 water vapor imagery and highlighted in
guidance with continued to pivot through portions of the region.
As this occurs, 29.15z RAP soundings would suggest fairly
uniform drying of the troposphere throughout the rest of the
afternoon aside from some transient saturation in the low-
levels. Ongoing flurries will not have a difficult time
maintaining due to this low-level saturation being in the
dendritic growth zone coupled with some weak near- surface
omega. However, surface observations continue to suggest the
aforementioned dry slot has continued to aid in scouring our the
low-level stratus resulting in lesser coverage of flurries
across eastern portions of the local area. Certainly an
impressively dry airmass though with recent NAEFS percentiles
having precipitable waters of 0.1" being around the lowest
percentile of reanalysis climatology across portions of our
region.
As we head into the weekend and early next week, continued cold air
reinforcement with the upper-level trough and northwesterly flow
will keep our air temperatures cold for this time of year with
highs generally in the anywhere from the upper teens to upper
20s through Tuesday. Confidence continues to remain high that
wind chills will fall to around minus 5 to 10 degrees during the
morning hours areawide this weekend with the 29.12z HREF having
medium probabilities (30-60%) for wind chills below minus 10
degrees on Saturday morning. Additionally, with somewhat breezy
conditions, still expecting wind chills to remain in the single
digits into the afternoon hours this weekend, so overall will
feel quite chilly throughout the day. Otherwise, hints of low-
level saturation in recent RAP/HRRR soundings in the dendritic
growth zone over the weekend would suggest a few stray flurries
cannot be ruled out. However, given exactly how little moisture
is present from the aforementioned dry airmass advecting into
our region, this would be very low confidence and would not pose
any impacts regardless.
Tuesday Night - Thursday: Seasonable with Precipitation Chances
As we head towards Wednesday, the overall troughing pattern flattens
slightly in deterministic guidance with some subtle ridging
being able to sneak in ahead of a shortwave and surface low
passage to our north on Wednesday. This will allow for some warm
advection to squeeze in for Wednesday with the 29.00z grand
ensemble (GEFS/EC/Canadian ensemble) having median high
temperatures across the region generally in the 30s with
relatively low inter-quartile spread of around 5 degrees. This
generally appears to be short-lived with cold air advection
working in behind this shortwave. Still some uncertainty on the
timing on when this cold advection reaches our area with vast
inter-quartile spread (roughly 15-20 degrees of spread) in the
29.00z grand ensemble median high temperatures for Thursday at
La Crosse with highs anywhere from lower 20s to middle 30s.
Precipitation chances likely would manifest as snow during this
period with the 29.13z NBM showing every solution that has
precipitation for Tuesday night with the snow precipitation type
(anywhere from 20-50% of members east of the Mississippi River)
which would be consistent with the northern trajectory of the
shortwave and cold air advection regime behind it. Still questions
remain on the track and intensity of the wave as it skirts north of
the region though. Overall confidence is currently highest across
north-central WI for measurable snow on Tuesday night/Wednesday (60-
80% chance in the 29.00z grand ensemble) with lessening confidence
further southwest. Regardless, the overall pattern over the next
week can be summarized to generally cooler than normal
temperatures with the northerly flow regime and light snow
chances with any pieces of shortwave energy that can approach
the region.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 549 PM CST Fri Nov 29 2024
Currently watching a MVFR deck of clouds moving through the
western suburbs of the Twin Cities. Many of the models are not
handling these cloud. The GFS has some MVFR clouds, but they
dissipate as they move southeast into the area. The HRRR also
shows them and it brings them southeast through KRST between
30.03z and 30.07z and KLSE between 30.05z and 30.09z. For now,
went with scattered MVFR deck between 30.03z and 30.06z and kept
KLSE clear. Might even have to add some snow flurries. We will
continue to monitor them through this evening. Otherwise, there
looks to be no concern with low ceilings for the remainder of
the TAF period.
As diurnal mixing occurs on Saturday, west northwest winds
around 290 degrees will be sustained around 15 knots with gusts
of 20 to 25 knots.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Naylor
AVIATION...Boyne
Area Forecast Discussion
National Weather Service Charleston SC
908 PM EST Fri Nov 29 2024
.SYNOPSIS...
High pressure will build across the area through the middle of
next week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
The boundary layer has decoupled across many areas this evening
with temperatures falling quickly with calm winds and clear
skies. The gradient is expected to tighten slightly over the
next few hours as a weak shortwave passes through, which may
cause a brief recoupling in some areas. However, guidance is
similar in showing winds going calm/light again after 2-3 AM as
the gradient relaxes once again and the boundary layer
decouples.
The situation looks favorable for widespread frost/freeze away
from the immediate coast with lows poised to drop into the
upper 20s well inland to the lower 40 sat the beaches. The
earlier modifications to the going Freeze Warning and Frost
Advisory look on track with light drainage winds helping to push
lower- mid 30s well into much of the Georgia coast. Only
coastal portions of McIntosh and Bryan Counties look to escape
significant frost/freeze conditions along with far eastern areas
of Chatham County including Tybee Island and possibly Wilmington
Island. Farther up the lower South Carolina coast, areas around
Hilton Head, the Broad River and many of the small islands in
central/southern Beaufort County look safe along with the
immediate coastal communities of Colleton and Charleston
Counties, including Downtown Charleston.
The growing season for Southeast South Carolina and much of
Southeast Georgia will end tomorrow.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
Broad troughing aloft will prevail across the East Coast into
Monday, while high pressure will build into the local area from
the west. A rain-free forecast has been maintained, with the
high pressure ushering in a dry, cool airmass. Temperatures
Saturday night are forecast to dip into the upper 20s far
inland, with 30s along the coastline, the beaches should remain
near 40. Areas to widespread frost is likely to develop away
from the beaches, however the local Frost/Freeze season ends on
Saturday, November 30th. Therefore, we will no longer issue
Frost/Freeze Watches or Warnings for the season.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Little change in the overall synoptic pattern is expected
through the work week. Northwesterly flow aloft will dominate as
the east coast is under the influence of large scale troughing
in the upper levels. At the surface high pressure will build
into the region, centered over the southeastern states. The main
forecast highlight will be the below normal temperatures. Highs
on Tuesday will likely struggle to get out of the 40s across
many locations, with overnight lows in the 20s to around
freezing directly at the coastline. A slight warm up is expected
Wednesday and into Thursday, with highs Thursday in the low to
mid 60s.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
30/00z TAF Discussion:
KCHS/KJZI/KSAV: VFR.
Extended Aviation Outlook: VFR.
&&
.MARINE...
Tonight: Winds will surge overnight with the passage of a
shortwave aloft. North winds will increase to 20-25 kt for
several hours overnight per the latest trends noted in both the
RAP and H3R. The Small Craft Advisory has been expanded to
include all remaining nearshore legs with the late evening
update. Only the Charleston Harbor looks to remain out of
advisory level winds. Seas will build 2-4 ft overnight.
Saturday through Wednesday: High pressure will prevail across
the marine waters through the week, with generally tranquil
conditions forecast across the waters. Northwesterly winds are
forecast, generally around 10 to 15 knots, with some gusts
approaching 20 knots. Seas should average 2 to 4 ft through the
week.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Freeze Warning from 1 AM to 9 AM EST Saturday for GAZ087-088-
099>101-114>116-118-137-138.
Frost Advisory from 1 AM to 9 AM EST Saturday for GAZ117-119-
140.
SC...Freeze Warning from 1 AM to 9 AM EST Saturday for SCZ040-
042>045-047-050-052.
Frost Advisory from 1 AM to 9 AM EST Saturday for SCZ048-049-
051.
MARINE...Small Craft Advisory until 7 AM EST Saturday for AMZ350-352-
354-374.
&&
$$
Area Forecast Discussion
National Weather Service Cleveland OH
1044 PM EST Fri Nov 29 2024
.SYNOPSIS...
A low pressure system north of the region will keep a surface trough
across the area into the start of next week. Another low pressure
will move east across the northern Great Lakes, impacting the area
again for mid-week.
&&
.NEAR TERM /THROUGH SATURDAY NIGHT/...
Lake effect snow continues to pile up along the northeast
lakeshore leading to very hazardous conditions. Snowfall reports
this evening have surpassed a foot and a half in Ohio with
reports of over 2-2.5 feet in Erie County Pennsylvania. We have
received reports of stranded motorists and downed limbs due to
the weight of the snow. Travel in eastern Lake, northern
Ashtabula, and Erie County PA is strongly discouraged as this is
becoming a very serious situation.
Unfortunately heavy snow continues to fall with rates of 1 to 2
inches per hour. A heavy band has re-oriented across eastern
Lake and Ashtabula county while another heavy band is across
eastern Erie County PA into New York. Snow is expected to
continue through the night with strong intensity given westerly
flow through 700mb, ample moisture, a warm lake and a cold
airmass. Not until the southwest flow lifts the band out over
the lake on Saturday morning is a real break expected. The
combination of the duration and high snowfall rates means 12-18
inches are likely under the heavier band and can not rule out a
few places(most likely in Ashtabula County) exceeding another 2
feet. A sharp cut-off still remains to the south with southern
portions of Geauga, Ashtabula, and Crawford Counties likely to
receive little if any accumulation. In Cuyahoga County, Euclid
is the main concern and have chosen to leave the Advisory in
effect given the close proximity to the heavy band. Most of
Cuyahoga County will receive little or no snow.
Colder air located south of the lake will continue to favor the
surface trough holding on along the lakeshore overnight. The
RGEM has been a preferred model which continues to focus the
trough axis near the shoreline, allowing less inland extent of
snow. Unfortunately this does place the heaviest of the snow in
areas that have already been hit hard. Roads are becoming
impassible in this dangerous situation. A concerning trend on
the 00Z/30 HRRR shows the band struggling to clear Erie County
on Saturday. We will be analyzing model trends to determine if
the Warning needs to be extended on Saturday.
Previous discussion...A potentially historic lake-effect
snowstorm will continue across far NE Ohio and NW PA tonight
through Saturday morning as a long fetch, westerly flow of cold
air interacts with near record warm lake temperatures.
In terms of the pattern, a closed mid-level low near James Bay
will gradually pivot into Quebec through the weekend as the
associated broad, deep mid/upper trough continues across the
Great Lakes. This will maintain a broad cyclonic flow of cold
air and sufficient synoptic moisture across the Great Lakes,
with a series of shortwaves oscillating the boundary layer wind
fields, causing lake-effect bands to wobble. Lake induced
instability will remain strong to extreme through the period, as
equilibrium levels reach 20 thousand feet at times with very
steep lapse rates.
Doppler radar loops this afternoon show that the main band has
become wider and more cellular from the western basin of Lake
Erie to northeastern Lake, northern Ashtabula, Erie, and extreme
northern Crawford Counties. This is due to daytime heating
slightly disrupting the boundary layer thermodynamics over the
lake and the instability snow showers developing on land.
However, the boundary layer flow has been steadily veering more
westerly, and this is causing the band to sag slowly southward.
Expect that once the sun sets, the band will quickly regain
organization and turn into a highly focused, intense plume
targeting eastern Lake, NE Geauga, northern/central Ashtabula,
Erie, and northern Crawford Counties as a mainly 270 degree flow
locks in from this evening through much of the night. The HREF
members continue to show the typical south bias, but they have
not been terrible this afternoon overall. The RGEM continues to
have the best handle on band placement, although a little too
far north. With this in mind, opted for a placement between the
RGEM and HREF. This is a serious situation because this places
the heaviest snow this evening and tonight over areas that have
already been hit very hard today. Reports from northern Erie
County have been in the 15 to 25 inch range since the snow began
late last night, with reports of over 8 inches in 2.5 hours
around midday today! Additional snowfall of 18 to 24 inches is
likely in northern Erie County through Saturday morning, with
locally up to 30 inches. Additional snowfall of 12-18 inches
with locally up to 24 inches is expected through Saturday
morning in eastern Lake and northern Ashtabula Counties. Just
south of this swath, additional amounts of 8-12 inches are
expected from about NE Geauga to central Ashtabula Counties.
This will place storm totals in the 3 to 4 foot range in the
hardest hit areas, with locally up to 50 inches in northern Erie
County!
In terms of headline decisions, opted to keep ongoing Lake-
Effect Snow Warnings through 15Z Saturday for Lake, Geauga,
Ashtabula, and Erie and Crawford Counties. Geauga is close, but
there is enough confidence that the band will clip the Thompson
area this evening and the first half of tonight to bring warning
amounts to the far NE parts of the county. Cuyahoga County has
the greatest "bust" potential. The band could affect Euclid
(extreme NE Cuyahoga) for several hours this evening and early
tonight, so kept a small area of additional snowfall near 3
inches. These amounts could be a couple of inches higher or
lower depending on how it orients after dark, so there`s a
possibility the Advisory may need to be cancelled. If the band
orients slightly farther south, then the Advisory is fine. This
will be watched this evening.
Late tonight and Saturday, the boundary layer flow is still
projected to back rather quickly ahead of a stronger shortwave
dropping into the Great Lakes. This will start to steadily lift
the band northward before sunrise Saturday and through midday.
Trends have been for this to happen a little slower, so held
onto higher PoPs along the Erie, PA lakeshore through early
afternoon, but it will end on the Ohio lakeshore 12-15Z. By mid
afternoon, all of the snow should be over the lake as the band
reorients into the Buffalo area. This will give a needed break
to dig out.
Unfortunately, the aforementioned shortwave will move into the
southern Great Lakes Saturday night and start to veer the flow
more westerly again. This will start to push the band back into
NW PA and extreme NE Ohio overnight. There will be stronger
boundary layer shear Saturday night, so that will likely make
the band more ragged and cellular, but it will start to snow at
least moderately along the lakeshores of far NE Ohio and NW PA
again. The band will likely be slower than guidance to move back
south due to lake aggregate troughing, so slowly expanded PoPs
back south and westward. This will take us into part 2 of this
lake-effect snowstorm, so see the short term and long term
sections for details on that.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
The large and cold cyclonic flow will continue Sunday into Monday
but there will be some subtle changes in the low levels which will
shift the lake effect snow bands. On Sunday, center of mid level
trough will move to just north of New York state in southern Quebec.
The low level flow will start out on Sunday from the west-southwest
which will keep ongoing lake effect snow bands hugging near the
lakeshore area of far NEOH and NWPA through the afternoon. A surface
trough will push across the area Sunday night. The low level flow
will become more west-northwest Sunday night through Monday night.
This change in the flow will shift the potential of lake effect snow
bands more into north central and northeast Ohio as well as NWPA.
Some of the secondary snowbelt areas will come into play with the
lake effect snow potential, including more of the Cleveland metro
area. There could also be a Lake Huron connection that develops for
NWPA and the Erie PA area late Monday into Monday night. Additional
heavy snowfall is very possible for more of the Cleveland area and
eastward towards NWPA. Additional winter headlines will likely be
needed for some portion of NEOH and NWPA. Areas outside of the
Snowbelt will have relatively quiet weather with some passing light
snow showers from time to time with little to no accumulations or
impacts. Temperatures will be cold and below average Sunday into
Monday with highs in the 30s and overnight lows in the upper teens
and 20s.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
The upper level weather pattern will start to change on Tuesday. The
upper level trough will start to pull away late on Tuesday. The low
level flow will start out westerly on Tuesday which will push the
lake effect snow bands into far NEOH and NWPA during the day. The
flow becomes more southwesterly by Tuesday evening and push the lake
effect either out into Lake Erie or hugging the lakeshore of far
NEOH and NWPA Tuesday night. The upper level pattern briefly will
be more zonal by Tuesday night. A strong shortwave trough will dive
down through the Great Lakes region on Wednesday with a deepening
surface low tracking through the Upper Great Lakes. An area of snow
will spread over much of the region by Wednesday morning with a warm
front. Snow, briefly mixing with rain at times on Wednesday is
expected with light snowfall accumulations possible areawide. As the
strong low pressure system passes by to our north, a cold front will
move through Wednesday evening. It will become windy Wednesday
through Thursday with gusts easily up to 35 mph.The areawide of snow
will transition back to organized lake effect snow bands for both
the primary and maybe the secondary snowbelt Wednesday night through
Thursday night with additional localized heavy snow possible.
&&
.AVIATION /00Z Saturday THROUGH Wednesday/...
A heavy and persistent band of lake effect snow will continue to
impact ERI airport through tonight, before southwesterly winds
push this band north over Lake Erie on Saturday morning. This
band has shown signs of re-organizing and gaining strength again this
evening and is likely to maintain LIFR conditions with
visibilities often around 1/4 mile through most of the
overnight. It is hard to tell when improvement may occur, but
looking for improvement sometime on Saturday morning. Snow will
be in the vicinity on Saturday but likely to push north over
Lake Erie. Elsewhere, scattered snow showers that we
experienced this afternoon are expected to taper off this
evening with drier low level air arriving. At CLE, snow is not
likely to impact the terminal while a heavy band remains just a
few miles north over Lake Erie. Conditions at remaining airports
are generally expected to be VFR through the TAF cycle.
Southwesterly winds of 10-12 knots will gust to 20-25 knots
through late Saturday afternoon. Gusts may become less frequent
late tonight before resuming again on Saturday morning.
Outlook...Non-VFR likely in periodic lake-effect snow through
Tuesday. The heaviest and most-persistent lake-effect snow in
our region is expected to impact the primary snowbelt in far
Northeast Ohio and Northwest Pennsylvania. CLE may see light
snow accumulations Sunday night into Monday morning.
&&
.MARINE...
A large low pressure system north of the Great Lakes will keep winds
elevated and rough conditions on Lake Erie this weekend through
early next week. Winds this weekend through early next week will
generally be from the west 15 to 25+ plus with gusts up to 35 knots
at times with organized snow squalls. There might be some slight
variation of the westerly flow at times, turning more west-northwest
or west-southwest. Waves will remain high especially for the central
and eastern basin of Lake Erie over the next several days. Small
Craft Advisory are in effect and may need to be extended further in
duration over time with no changes in the weather pattern expected
through middle of next week. By Wednesday, a strong low pressure
system may develop and track across the Upper Great Lakes which will
change our winds briefly from the south 20 to 30 knots before
returning to west-northwest winds following a cold front. Low water
advisory remains in effect into Saturday with the latest water level
at Toledo 2.7 inches below the low water datum. The critical water
level for safe navigation is 3 inches above the low water datum.
Water levels will slowly increase and improve late on Saturday over
the western basin of Lake Erie.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Winter Weather Advisory until 10 AM EST Saturday for OHZ011.
Lake Effect Snow Warning until 10 AM EST Saturday for
OHZ012>014-089.
PA...Lake Effect Snow Warning until 10 AM EST Saturday for PAZ001-
002.
MARINE...Low Water Advisory until 1 PM EST Saturday for LEZ142>144-
162>164.
Small Craft Advisory until 10 AM EST Saturday for LEZ142-143.
Small Craft Advisory until 7 AM EST Monday for LEZ144>149.
&&
$$
SYNOPSIS...Garuckas
NEAR TERM...KEC/Garuckas
SHORT TERM...Griffin
LONG TERM...Griffin
AVIATION...KEC
MARINE...Griffin
Area Forecast Discussion
National Weather Service State College PA
939 PM EST Fri Nov 29 2024
.SYNOPSIS...
* Wind chills will drop as low as the single digits this weekend
and continue through the first week of December.
* Multiple bouts of lake effect and upslope snow are in store
over the next week.
* Some minor moderation with high temperatures by the middle of
next week, along with a bit more sun and less wind.
&&
.NEAR TERM /UNTIL 7 AM SATURDAY MORNING/...
Mid evening update.
Given the time of day and abnormally warm Great Lakes water
temperatures, winds should hold to the southwest, helping aid in
keeping the main band of snow off Lake Erie mainly north of our
area overnight.
There will be still some snow showers around across the far
north, and at times across the higher terrain to the south.
Thus will keep current products up until 7 AM Saturday morning.
Depth of cold air deeper this evening than last evening, which
aided in the formation of heavier snow showers earlier today.
Temperatures on track, as colder air works into the area.
Earlier discussion below.
The main snow band over far NW PA and wrn NY is thus far
keeping mainly out of Warren/McKean Cos. This has caused
thoughts of dropping/downgrading the warning and advy there, but
confidence is very low (30pct) that the LES will stay away or
continue to be rather lame all night. The latest HRRR actually
breaks the one larger band into at least two with one pointed
directly into Warren Co. As the air is getting drier, the
fluffiness of the snow increases. This will make it easier for
the snow to build up. So, we`ll hold the line on those hazards.
The LES should lift all north of the CWA in the morning,
allowing the warning and advisory to die on time or even be
cancelled early/overnight.
The wind stays gusty all night, generating wind chills near zero
in the highest terrain of Somerset Co, and lower teens in the
lowest elevations/cities of the Lower Susq. MinT is a slight
challenge with the sky trying to clear over much of the area,
but the wind staying up. Will keep them right with guidance for
now, which plays the middle ground in the envelope of possible
temps.
&&
.SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY/...
Mid evening update.
While it will be cold this weekend, temperatures far away from
record low values one can see this time of year. Hard to
believe it is the end of November, November will still average
several degrees warmer than normal, even with this shift in the
weather pattern.
Earlier discussion below.
A brief break in SHSN will be accompanied by some really
blustery conditions with maxes another 3-5F colder than Fri. The
gusty west wind will keep wind chills between 10-15F during the
daylight hrs over the wrn mtns, and teens and L20s elsewhere.
A potent shortwave trough dives E out of the Rockies and across
the OH Valley into the central Appalachian Mountains late Sat
night and Sunday. That will generate SHSN for the Laurel
Highlands, but mainly Somerset Co. At this point, the moisture
looks very limited, and accums will probably be under advy level
(widespread 3"), but the tallest elevations and west-facing
slopes in Somerset Co could see more. The rest of the area
should stay dry and partly cloudy Sat night.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Mid evening update.
Potential for snow showers to get further inland across central
PA will increase later Sunday into Tuesday, as winds become more
northwest.
Conditions may moderate a bit by mid to late week, but will
still be colder than we have had this fall so far.
Week 2 in December will be interesting to see how much mild
air can work in from the northwest.
Earlier discussion below.
Boundary layer flow becomes more west-northwesterly on Monday
and into Tuesday behind a departing shortwave which will allow
for lake effect snow bands to move into northwestern
Pennsylvania. Most guidance suggests that the heaviest snowfall
will be confined to Warren and McKean counties. By the middle of
the week, flow once again becomes more southwesterly ahead of
an approaching low pressure system. Ensembles seem to be coming
into agreement that this low will track over the Great Lakes and
will bring light snowfall to most of Central PA Wednesday into
Thursday. Cyclonic flow remains overhead through the end of the
week and will support continued upslope snow showers over the
western mountains and lake effect snow over the northwest.
Temperatures will remain well below normal through the extended
period with highs generally in the 20s and 30s and lows in the
teens and 20s.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Snow showers have become more isolated in nature across west-
central PA this evening as most large scale lift has moved east
of the area. Heavier snow is confined to a wide band of lake
effect downwind of Lake Erie, generally staying west and north
of BFD. Winds will remain up through the night, with occasional
gusts to 25-30 kts.
Most of Central PA will be VFR tonight into Saturday, but MVFR
clouds are possible at BFD and JST as early as 05z Sat and
lasting as late as 21z Sat. However, given the marginally dry
airmass, MVFR cigs are not expected during this entire window.
An upper level shortwave trough will swing across the OH valley
and into the central Appalachian Mountains Saturday night. This
feature will likely drop conditions to MVFR and possibly IFR
during the daylight hours Sunday at JST, with lower chances of
MVFR at the other TAF sites.
Outlook...
Sun Night-Tue...Continued breezy west winds. Prolonged chances
for MVFR/IFR conditions with snow showers across the north and
west.
Wed...Higher chances for widespread restrictions with snow in a
Clipper system.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 7 AM EST Saturday for PAZ004.
Winter Weather Advisory until 7 AM EST Saturday for PAZ005.
&&
$$
SYNOPSIS...Dangelo/Banghoff/Martin
NEAR TERM...Martin
SHORT TERM...Dangelo/Martin
LONG TERM...Martin/Bauco
AVIATION...Dangelo/Colbert
Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
556 PM CST Fri Nov 29 2024
.KEY MESSAGES...
- Light snow likely tomorrow morning, especially toward central
Missouri.
- Most areas should receive only a dusting to 1" of snow.
- 1" to 4" of snow is possible across central Missouri,
primarily along and north of Interstate 70.
- Colder than normal temperatures continue into early next week.
&&
.DISCUSSION...
Issued at 146 PM CST Fri Nov 29 2024
Current water vapor imagery overlaid with 500 mb heights and
winds shows longwave troughing across much of the CONUS with
strong northwest flow aloft over the region. The clipper system
that will impact us tomorrow morning is currently over southern
British Columbia and into northern Washington State. By midnight
tonight, it should be over the Front Range, with the vort max
and a 65+ knot 500 mb jet streak entering into central Kansas
by around 6 am tomorrow, yielding forcing to ascent across the
region. Modest theta e advection will yield slightly increased
dew points and PWATs, helping to provide enough moisture to
develop snow.
Light snow will likely begin sometime around 4 to 6 am tomorrow
morning, with the prime time still looking like 6 am to noon
with the potential for a FGEN enhanced snowband, especially
toward central Missouri along and just north of Interstate 70.
Even though we are less than 24 hours out, CAM guidance is still
relatively varied. The NAM NEST continues to be the most
bullish on snow amounts while the HRRR is much less excited.
Have trended toward the 12z SPC HREF for snow totals, with a
small area of 2-4" possible in the Marshall/Boonville/Moberly
areas of central Missouri, and as such a winter weather advisory
has been issued for these locations. Elsewhere, a dusting to 1"
is likely for most areas (including the KC metro). That being
said, just a slight shift in where the FGEN band sets up could
have a big impact on where we see enhanced snow totals.
Accumulating snow should completely exit our CWA to the east by
early afternoon, although some flurries could continue across
northern, northeastern, and central Missouri through the
afternoon and evening hours. Temperatures tomorrow night are
expected to be quite chilly, with lows in the mid teens to lower
20s.
Cooler than normal temperatures will persist into Sunday and
Monday as we remain beneath strong northwesterly flow aloft on
the backside of longwave troughing. Highs for Sunday and Monday
are forecast to be in the 30s with overnight lows in the teens.
A warming trend is likely to begin Tuesday and continue into the
middle of next week, with high temps returning to the upper 40s
to mid 50s by Wednesday of next week with dry conditions
prevailing. Another shortwave trough is projected to descend out
of Canada and into the Midwest on Thursday, sending a cold front
through the area and ushering in cooler temperatures for
Thursday and especially Friday.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 543 PM CST Fri Nov 29 2024
VFR conditions persist through the evening. Lowered CIGs move in
ahead of a passing system which looks to bring -SN Saturday
morning. Periods of low end MVFR to IFR are expected. -SN moves
out of the area by midday; however, MVFR CIGs linger through the
remainder of the period.
Winds remain light and variable becoming easterly by midnight
and northeasterly Saturday afternoon.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...Winter Weather Advisory from 4 AM to 2 PM CST Saturday for
MOZ031>033-039-040-046.
KS...None.
&&
$$
DISCUSSION...Williams
AVIATION...Pesel
Area Forecast Discussion
National Weather Service Goodland KS
506 PM MST Fri Nov 29 2024
.KEY MESSAGES...
- An extended period of dense fog may develop over portions of
northwest Kansas and southwest Nebraska Saturday morning,
mainly along and east of a line from Benkelman to Colby to
Gove City between 3-10 AM CST.
- Dry weather continues through next Friday.
&&
.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 1239 PM MST Fri Nov 29 2024
Across the Tri State region this afternoon, skies are mainly
sunny except for some scattered high cloud west and north. With
a surface trough over eastern Colorado, there is a south-
southwest gradient over the area around 10 mph, with some
isolated gusts around 20 mph. Temperatures are mainly in the 40s
with some 30s in the far east.
The main weather concern for the short term period will be the
potential for patchy freezing fog in eastern portions of the
area late tonight into Saturday morning.
For the remainder of the afternoon hours, mainly sunny
conditions with near to above normal temperatures. Southerly
flow will diminish as sunset approaches. Going into tonight,
short term guidance brings a backdoor cold front into the CWA by
06z Saturday. This will be followed by a ridge axis nosing into
eastern portions of the CWA through Saturday morning before it
shifts east. Expecting fog to develop for areas along/east of
Highway 25. With the overall track of the ridge axis rolling
through mainly areas along/east of Highway 83, have mentioned
the best potential for fog formation there. This is close to
previous forecast. Overall guidance is mixed as to the
strength/extent of the fog, with some down to a mile or less for
a good portion east of Highway 25, and some just focusing
along/east of Highway 83. With the inconsistency, have focused a
3-6sm swath from Red willow county south and east-southeast
into Norton/Graham counties through about 12z-15z Saturday. With
temperatures expected to range below freezing during this time,
the fog could freeze on elevated surfaces/roadways and pose
potential travel issues. This will have to be monitored in later
shifts as newer guidance becomes available.
For the remainder of the weekend, NW flow aloft with amplified
ridging over the west. High pressure building off the Rockies
will keep the CWA precip-free. The only thing to monitor will be
the potential for more overnight/early morning fog as the ridge
transitions over the Plains. Downslope, warming flow overnight
saturday should keep fog down, but Sunday night winds will be
light/variable as RH increases towards the 12z Monday timeframe.
For temps, highs this weekend will range mainly in the 40s
area- wide, but Sunday could have some western locales
approaching the lower 50s, especially along the Hwy 25/27
corridors. Overnight lows will range in the upper teens to lower
20s tonight and Saturday night, with 20s expected Sunday night.
With these expected temperatures, clear skies and some wind,
wind chill readings will range mainly in the lower to mid teens.
Some locales along/west of Highway 27 may only see readings in
the upper single digits above zero towards sunrise.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 1144 AM MST Fri Nov 29 2024
The latest runs of the GFS and ECMWF continue to show
persistent NW flow aloft at 500 mb during the period, with a
weak shortwave passing north of the area late Thursday into
Friday. At the surface, there will be several areas of high
pressure passing to the east of the CWA. This will be in between
lee-side troughing coming east off the Front Range and through
the central Plains. The overall result of these passing through
the region will be several shifts from a southerly warm flow to
northerly flow. While no precipitation is expected, there
continues to be the chance for patchy fog to develop in the east
as each surface ridge passes by the area during the overnight
and early morning hours, especially next Wed-Thu nights but will
be highly dependent on the strength of the wind gradient each
night. Also the passage of the aforementioned shortwave looks to
only bring some increased cloud cover, for northern/eastern
zones. This may hamper fog formation to a degree.
For temps, looking for highs on Monday to range mainly in the
40s. Areas along/east of Highway 83 may only see the upper 30s.
50s for Tuesday and Wednesday will give way to a mix of 40s and
50s for next Thursday and Friday. Overnight lows, mainly in the
20s for most nights. Monday night in northeast portions of the
Tri State area may see mid and upper teens.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 500 PM MST Fri Nov 29 2024
GLD: VFR conditions are anticipated to prevail through the TAF
period. An extended period of dense fog may develop over
portions of northwest Kansas Saturday morning.. mainly
along/east of a line from Benkelman to Colby to Gove City
between 07-16Z. While fog is expected to remain east of GLD..
current and recent runs of the HRRR suggest that fog may be in
relative close proximity (within 30 miles). Light/variable winds
will shift to the NW and increase to 10-15 knots late Saturday
morning (~16Z). Winds will weaken and become light/variable
around or shortly before sunset Saturday evening (~23Z).
MCK: An extended period of dense fog may develop over portions
of southwest Nebraska Saturday morning.. mainly along/east of a
line from Benkelman to Colby to Gove City. Sub-VFR conditions
assoc/w fog are expected at the MCK terminal between ~07-16Z.
LIFR-VLIFR conditions are possible in the ~08-12Z time frame.
Fog will dissipate by late morning and VFR conditions will
prevail through the remainder of the TAF period. Light and
variable winds will prevail through most, or all, of the TAF
period.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...None.
CO...None.
NE...None.
&&
$$
SHORT TERM...JN
LONG TERM...JN
AVIATION...Vincent
Area Forecast Discussion
National Weather Service Wilmington OH
919 PM EST Fri Nov 29 2024
.SYNOPSIS...
Snow showers and flurries are expected tonight in a brisk
westerly flow. A disturbance is forecast to bring light snow
accumulations Saturday night into Sunday. Drier weather arrives
later on Sunday after the disturbance moves east.
&&
.NEAR TERM /THROUGH SATURDAY/...
Flurries/ moderate snow showers have continued to push through
the region this evening, allowing for a light dusting on
roadways/sidewalks/elevated surfaces. Given that this is weakly
forced precip in cyclonic flow, there isn`t much guidance to
help with end time, however, looking at the HRRR/RAP and NAM
850mb RH... the highest moisture content looks to move east out
of the ILN CWA by midnight tonight or shortly after, so have
tapered off snow showers around that time.
Winds remain elevated overnight, around 10-15 MPH with some 20
MPH gusts. Currently, temps across the region are in the low 20s
and feels like temps are in the single digits. Clouds clear out
as that moisture moves east and we should end up with mostly
clear skies after midnight. Therefore, have tweaked overnight
lows a tad lower and dropped them comfortably into the teens
area wide as radiational cooling processes will take over.
Previous discussion--> Weak boundaries and disturbances
embedded in a cyclonic westerly flow are triggering snow showers
and flurries from a relatively shallow layer of moisture and
instability. Main area of concern is roughly from I-70 south to
the Ohio River. This loosely organized band of snow showers is
best represented on the HRRR which shows minor accumulations
late this afternoon through this evening. Went well above NBM
pops for this short duration event. Main impact appears to be
brief reductions to visibility with winds gusting over 20 knots
in some of the heavier snow showers. Road temperatures suggest
that slippery spots will not be common, but conditions could
worsen somewhat after sunset. Expect drier weather after
midnight when the cyclonic flow may weaken as winds back about
20 degrees.
Temperatures will be cold, with lows in the mid and upper teens,
and wind chills in the single digits above zero.
&&
.SHORT TERM /SATURDAY NIGHT/...
Saturday begins dry with high pressure building to the south.
That will change late Saturday afternoon and Saturday evening
thanks to a short wave disturbance in the mid level flow. Models
have been relatively consistent regarding this system, showing
light snow accumulations mainly along and south of the Ohio
River. 1 to 1.5 inches of accumulation are indicated by the
latest model estimates in those southern locations such as
Owenton and Maysville KY, with lesser amounts forecast as we go
farther north to Dayton and Columbus. There may be some travel
impacts to the southern areas by Sunday morning.
Temperatures staying below normal are forecast to rise to the
upper 20s to mid 30s Saturday, falling to the upper teens to mid
20s Saturday night.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
On Sunday morning, broad troughing will remain in place across
the eastern half of the CONUS, with a shortwave moving through
the Ohio Valley and into the mid-Atlantic region. The broad
trough will dominate the weather pattern through the extended
forecast period, with temperatures below normal being the main
issue. There may be a brief warm-up heading into Thursday,
before cold conditions settle in again for Friday and likely
beyond.
The Sunday morning snow will be exiting the area by early afternoon,
with only light additional accumulations in the southeastern ILN CWA
before ending.
The next chance for precipitation will be late Tuesday night into
Wednesday. After the broad trough finally moves to the east, a brief
but notable period of height rises will occur, with theta-e
advection -- primarily at 850mb and above. This mid-level forcing
will be focused to the north of the ILN area, but it is expected
that some precipitation will spread into the region from northwest
to southeast. The main issue with this precipitation will be
determining the precipitation type. Initially, the boundary layer
will be cold enough to support all snow (through Wednesday morning)
before some switch to rain occurs where temperatures are able to
warm on Wednesday, as the thermal profile switches from an inversion
to one with steeper lapse rates. It is not totally out of the
question that some chance for light freezing rain could occur with
this kind of pattern developing over cold antecedent conditions, but
probabilities for this to occur -- on a Day 5 forecast -- remain
small. The main story for Wednesday morning at this point is that
some wintry precipitation will be possible, but with little
confidence in any notable impacts. After this precipitation ends
late Wednesday, some additional precipitation chances may come into
the picture for the end of the week.
This brief warm-up on Wednesday and Thursday will only bring
temperatures back to values near normal -- or even maybe just short
of normal. By the end of the week, another southward moving cold
front will bring a return to temperatures well below normal.
Winds are worth noting through the extended period as well. As the
mid-week system moves through the area, this will be the period with
the tightest pressure gradient, as a surface low moves across
Michigan. Current models suggest this will be on Wednesday, with
some potential for gusts in the 20-30 knot range.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Light to moderate snow showers continue to move through the
region, primarily affecting the northern TAF sites. These
showers continue through midnight, then taper off. Winds remain
elevated as we head into the first half of the night, with gusts
to 25 knots possible through 02z ish. Then, gusts decrease and
we`re left with WNW winds around 10 knots.
After snow moves east, conditions improve to VFR for all sites.
Clouds clear out and we`ll be left with some scattered cu for
the early morning on Saturday, persisting into the afternoon.
Winds increase yet again, shifting to westerly around 12 knots,
gusting to 25 knots through Saturday afternoon.
Clouds begin to thicken and lower as we head into the late
afternoon hours Saturday ahead of our next weather maker that
arrives Saturday night. For now, have trended this into all TAF
sites and included arrival of snow showers, MVFR and IFR
CIGs/VSBYs into the extended CVG TAF.
OUTLOOK...MVFR/IFR conditions possible Saturday night into
Sunday, particularly for sites along/near the Ohio River.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...Coniglio
NEAR TERM...CA/Coniglio
SHORT TERM...Coniglio
LONG TERM...Hatzos
AVIATION...CA
Area Forecast Discussion
National Weather Service North Platte NE
546 PM CST Fri Nov 29 2024
.KEY MESSAGES...
- Flurries and light snow are possible tonight into Saturday
morning across portions of northern Nebraska. Travel impacts
are not expected.
- Temperatures will be near normal through the weekend across
the southwest and about 10 degrees below normal across the
northeast. A warming trend Tuesday and Wednesday as highs
return to the mid 40s to mid 50s. Dry conditions are expected.
&&
.SHORT TERM /THROUGH SUNDAY/...
Issued at 157 PM CST Fri Nov 29 2024
Northwest low aloft will persist across the Northern and Central
Plains tonight through Sunday. Surface high pressure will persist
across the Dakotas. A weak disturbance currently embedded in the
upper flow in eastern Montana will drop southeast through western
South Dakota this evening and northeast Nebraska late tonight.
Weak isentropic upglide shown on the 285K surface across southwest
South Dakota into north central Nebraska this evening. Some
saturation shown up through the 305K surface across southwestern
South Dakota through northeast Nebraska overnight, then diminishing
quickly Saturday morning. The NAM bufkit sounding shows saturation
up through 400mb and periods of weak lift in the minus 10C to minus
20C dendritic layer tonight. This will be across the northeastern
counties mainly east of a line from Valentine through Bartlett. Very
little QPFs below 0.05" are shown by deterministic NAM and Canadian
models, while the GFS and ECMWF are mainly dry. Continuing a
slight chance for light snow and mention of flurries across the
above mentioned area. Little if any accumulation is forecast, so
impacts to travel are not expected.
Fog development is likely across portions of southwest Nebraska
beginning midnight tonight and lasting through late Saturday
morning. The HRRR and RAP are in close agreement on location,
including much of southwest Nebraska. Surface low pressure in
eastern Colorado this evening will move into south central Kansas
overnight, bringing in a weak backdoor cold front and favorable fog
formation.
Saturday, highs again reach the low to mid 40s across the southwest,
while the northeast remains colder in the upper 20s to low 30s.
Flurries may linger through mid morning, with winds becoming light
west to northwest in the afternoon.
Saturday night into Sunday, not changes in the weather pattern as
northwest flow aloft continues. Highs will range from the low to mid
40s southwest and the mid 20s to low 30s northeast.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Issued at 157 PM CST Fri Nov 29 2024
A backdoor cold front Sunday night will bring slightly colder
temperatures on Monday. Highs from the NBM were lowered to the mid
to upper 20s northeast to the mid 30s to low 40s west and southwest.
Looking ahead to Tuesday through Wednesday, upper ridging across the
western U.S. will bring height rises to the Central Plains with
westerly downsloping winds as highs return to the 50s west and
central. There will be colder air dropping south from the Northern
Plains and Great Lakes region Wednesday night into Thursday. Highs
cooler Thursday and Friday from the mid 30s northeast to the mid to
upper 40s southwest. Current forecast is dry in this extended period
as well.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 546 PM CST Fri Nov 29 2024
Active weather is expected through tonight with light fog across the
south and light snow in the north. At this time, current guidance
suggests snow will remain just to the east of KVTN and therefore, it
is not in the going TAF forecast. For the patchy fog, development is
expected after 06Z mainly across southern Nebraska, impacting KLBF
by Saturday morning. Fog is anticipated to remain thin with
visibility restrictions only down to 5 miles. Conditions improve by
mid-morning giving way to VFR conditions once again.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...Roberg
LONG TERM...Roberg
AVIATION...Kulik