weather

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Fri Dec 13 2024
Valid 12Z Fri Dec 13 2024 – 12Z Sun Dec 15 2024

…Atmospheric River to bring very heavy rainfall and possible flooding as
well as high elevation mountain snow to the West Coast…

…Heavy mountain snow forecast for portions of the Great Basin and
northern Rockies Saturday…

…Potentially impactful wintry mix with freezing rain expected across the
Middle Missouri Valley and Upper Midwest Saturday…

An Atmospheric River event will bring very heavy rain, mountain snow, and
gusty winds to portions of southern Oregon and northern/central California
Friday into Saturday. A Slight Risk of Excessive Rainfall (level 2/4) has
been issued along portions of the Coastal Ranges of northern California
where locally heavy rainfall rates of 0.5″ per hour and rainfall totals of
3-5″, with isolated higher amounts upwards of 7″, may lead to some
instances of flooding during the height of the event Friday
evening/overnight into Saturday morning. Very heavy mountain snow is
expected at higher elevations (generally over 5000-6000 feet) of the
Coastal Ranges and for the Sierra Nevada. Winter Storm Warnings have been
issued for forecast snowfall totals of 1-2 feet, locally higher. In
addition to the heavy precipitation, strong, gusty winds are also
expected, particularly for coastal locations. A broader area of more
moderate rainfall stretches across the Pacific Northwest and south along
coastal California. Some Moderate to heavy snow is also forecast further
north through the Cascades where 4-8″, locally higher, can be expected.
The system will continue eastward late Friday and into the day Saturday,
spreading moisture and precipitation chances further inland over the Great
Basin and northern Rockies. A mix of rain and snow can be expected at
lower elevations with snow, heavy at times, for higher mountain
elevations. Winter storm Watches have been issued for the mountains of
central Idaho where the heaviest snow is expected with forecast totals of
6-12″.

To the east, an upper-level wave passing from the Rockies and over the
Plains will help to organize a surface frontal system and encourage moist,
southerly return flow from the Gulf of Mexico. Showers and thunderstorms
are forecast ahead of an eastward moving cold front across eastern
portions of the central/southern Plains on Friday. More widespread storms
with moderate to locally heavy rainfall are expected on Saturday as the
system continues into the Middle Mississippi/Lower Ohio Valley. Some
potentially impactful winter weather is forecast further north across the
Middle Missouri Valley and into portions of the Upper Midwest where warm,
moist air overriding colder temperatures will lead to a wintry mix Friday
afternoon through Saturday. Snow/sleet accumulations should remain light,
but some freezing rain accretions are also expected. These accretions may
be greater than 0.1″ over eastern Iowa which could lead to some tree
damage and power outages. Regardless, the wintry mix will at least likely
lead to some travel troubles across the region.

Elsewhere, most lake effect snow will be tapering off Friday morning for
the Great Lakes except downwind of Lake Ontario where an additional 6-12″
can be expected through the day Friday. Some light to moderate snow
showers will also continue through the day Friday for the central Rockies
as a cold front moves through the region. High temperatures will remain
cold and below average for much of the north-central and eastern U.S.
following a frontal passage. Forecast highs range from the teens and 20s
for the northern Plains, Great Lakes, and interior Northeast; the 30s and
40s for the Ohio Valley and Mid-Atlantic/coastal Northeast; and the 50s
across the Southeast. Conditions will moderate closer to average Saturday
with highs generally running 5-15 degrees warmer. Forecast highs are
generally at or above average across the West, with 40s and 50s in the
Pacific Northwest, Great Basin, and Rockies; the 50s and 60s in
California; and the 70s in the Desert Southwest. Conditions in the
Southern Plains/Texas will be some of the warmest and most above average
compared to the rest of the country with highs into the 60s and 70s.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Thu Dec 12 2024
Valid 12Z Thu Dec 12 2024 – 12Z Sat Dec 14 2024

…Great Lakes heavy lake-effect snow expected to continue into Friday
especially along the Snow Belt of the lower Great Lakes…

…A couple rounds of heavy coastal rain and heavy mountain snow expected
to impact northern California into Sierra Nevada heading into the
weekend…

…Sub-zero temperatures expected over parts of the northern Plains and
upper Mississippi Valley for the next couple of mornings…

As a deep low pressure system races further northward into eastern Canada
and a potent cold front exits New England this morning, an arctic high
pressure system will take over the northern Plains and expand across the
entire eastern U.S. through the next couple of days. Maine will be the
last to clear out from the heavy rain early this morning followed by much
colder temperatures under blustery westerly winds. The resurgence of
arctic air is triggering a new round of heavy lake-effect snow across the
Great Lakes through today and tonight before gradually tapering off on
Friday. The Snow Belt of the lower Great Lakes can expect a foot or more
of new snow, with locations downwind from Lake Ontario possibly getting
more than 2 feet since these locations will be the last to clear out from
the snow late on Friday.

Along the West Coast, moisture ahead of the next Pacific cyclone is poised
to overspread much of the Pacific Northwest and a good portion of
California today. The heaviest precipitation is expected to reach
northern California in form of rain near the coast and lower elevations.
A quick round of moderate to heavy snow will then reach the high
elevations farther inland and then along the Sierra Nevada for much of
today. It appears that this latest around of precipitation will taper off
temporarily tonight before the next round of precipitation associated with
the next Pacific cyclone arrives on Friday. Northern California into
southwestern Oregon can expect heavy precipitation Friday night with a
marginal risk of excessive rainfall continuing into Saturday morning by
the end of the short-range forecast period. Lesser amounts of
precipitation are expected for the Pacific Northwest.

The arctic high pressure system that is forecast to bring sub-zero
temperatures for the next couple of mornings is forecast to strengthen and
slide east into New England by Saturday morning. This will allow
southerly flow to increase across the southern Plains along with moisture
returning from the Gulf of Mexico by Friday night. Meanwhile, residual
energy associated with the first Pacific system is forecast to exit the
southern Rockies and induce the formation of a low pressure system over
the central Plains by Friday night. Some thunderstorms along with heavy
rain could quickly develop and move across the central Plains early on
Saturday ahead of the new low pressure system. Colder air could support
areas of mixed rain and snow farther north across the north-central Plains
into the upper Midwest in advance of the low pressure center. In the
short-term though, dry, breezy and relatively mild conditions will support
elevated fire danger across the southern High Plains for today.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Wed Dec 11 2024
Valid 12Z Wed Dec 11 2024 – 12Z Fri Dec 13 2024

…Widespread heavy rain and severe thunderstorm treats spreading up the
East Coast today and through New England into tonight…

…A surge of cold air into the eastern U.S. today will be followed by a
reinforcing surge of arctic air into the northern U.S. through the next
couple of days…

…Another round of significant lake effect snow expected through the next
couple of days downwind of the Lakes...

The stage is set for a rapidly intensifying low pressure system to track
up the East Coast today. A potent cold front trailing southwest from the
center of this elongated low pressure system will be the focus for heavy
rain, blustery winds, and strong to severe thunderstorms. Ahead of the
front, warm and moist air streaming in from the nearby Atlantic and Gulf
of Mexico will interact more vigorously with a jet stream aloft to develop
and expand the coverage of showers and thunderstorms, first across the
Southeast and the Carolinas this morning, followed by the Mid-Atlantic
states during the day, and into New England this evening. The highly
dynamic nature of this front will likely trigger formation of strong to
severe thunderstorms. This is especially the case across eastern North
Carolina this afternoon, and into southern New England this evening, where
the Storm Prediction Center has issued a Slight Risk (level 2 of 5) for
severe thunderstorms capable of producing damaging wind gusts. Elsewhere
along the Eastern Seaboard, the main concern will be a period of heavy
rain with embedded strong thunderstorms and intense downpours. Despite
much of the region currently experiencing moderate to extreme drought
conditions, the rain, while mostly beneficial, could lead to some
localized instances of flash flooding. The more urbanized locations and
poor drainage areas would have the greater risk of flooding issues.

Behind the potent cold front sharply colder air will surge into the East
Coast from the north and northwest. A period of accumulating wet snow can
be expected to spread up the western slope of the entire spine of the
Appalachians from south to north today through tonight. Meanwhile, a
reinforcing shot of arctic air is plunging into the northern Plains and
will overspread much of the northern tier states through the next couple
of days. High temperatures the next couple of days will be roughly 10 to
as much as 30 degrees below normal.

Attention then turns to yet another round of significant lake effect snow
downwind of the Great Lakes through the next couple of days. The
aforementioned surge of arctic air will stream across the still relatively
warm Great Lakes and ignite intense bands of lake effect snow, initially
downwind of Lakes Superior and Michigan on today and then downwind of
Lakes Erie and Ontario tonight into early Thursday. By the time the snow
starts to taper off on Friday, snowfall totals of 1 to 2 feet are likely
in the favored Snow Belt across portions of northwest and western New York
State, far northwest Pennsylvania, far northeastern Ohio, the Upper
Peninsula of Michigan and the western portions of the Lower Peninsula of
Michigan.

Along the West Coast, moisture ahead of the next cyclone from the Pacific
is poised to overspread much of the region through the next couple of
days. Northern California will see heavy coastal rain by this evening,
followed by heavy mountain snow farther inland and down the Sierra Nevada
where a foot or more of new snow is forecast through Thursday. It appears
that this round of precipitation will mostly taper off Thursday night
prior to the arrival of the next Pacific system.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Tue Dec 10 2024
Valid 12Z Tue Dec 10 2024 – 12Z Thu Dec 12 2024

…Widespread heavy rain threat emerging across the central to eastern
Gulf Coast region today will spread rapidly up the entire East Coast on
Wednesday…

…Active Lake effect snows to begin Wednesday and continue through
Thursday downwind of the Lakes…

…Record warm morning lows likely along the east coast Wednesday
morning…

…Arctic air to surge south into the Northern Plains/Upper Mississippi
Valley region late Tuesday into Wednesday…

…Santa Ana winds along with critical to extreme fire weather danger
across portions of southern California…

The upper-level flow pattern across much of North America will undergo
significant amplification over the next few days, producing various types
of impactful weather across mainland U.S. The most active weather in
terms of precipitation and winds will be the primary focus along the East
Coast through the next couple of days. Precipitation currently falling
across portions of the Southeast is in its organizing stage ahead of a
developing low pressure wave over the Mid-South along a cold front. As
the cold air behind the front interacts with a rapidly amplifying upper
trough, rain and embedded thunderstorms will rapidly expand northeastward
during the day Wednesday and up the entire East Coast, producing a period
of widespread heavy rainfall from the central to eastern Gulf coast,
across the Southeast, Mid-Atlantic, Northeast and New England. With much
of these areas currently in moderate to extreme drought conditions, this
rainfall will be beneficial. Still, given the potential for periods of
heavy rains over a short period, there will be a threat of localized flash
flooding, especially in more urbanized regions.

The cold front associated with this rapidly intensifying system will
become rather potent as it sweeps across the East Coast during the day on
Wednesday. There is potential for some very strong thunderstorms to form
ahead of the front together with heavy downpours. Meanwhile, drastically
colder air behind the front is forecast to produce accumulating snowfall
up the western slopes of the Appalachians on Wednesday together with
blustery northwesterly winds. The snow will then sweep across interior
New England through Wednesday night into Thursday morning as a potent
elongated low pressure system races northward into southeastern Canada.

With a warm southerly flow strengthening ahead of this potent front, there
is the potential for widespread record high morning low temperatures on
Wednesday across the southern Mid-Atlantic, Mid-Atlantic and portions of
the Northeast. In the wake of this front, much colder air will stream
across the Great Lakes from west to east beginning on Wednesday. This will
ignite active lake-effect snows, initially downwind of Lakes Superior and
Michigan on Wednesday and then downwind of Lakes Erie and Ontario
Wednesday night into early Thursday. Before these lake-effect snows
diminish by early Friday, snowfall totals of 1 to 2 feet are possible in
the favored Snow Belt across portions of northwest and western New York
State, far northwest Pennsylvania, far northeastern Ohio, the Upper
Peninsula of Michigan and the western portions of the Lower Peninsula of
Michigan.

The above-mentioned lake-effect snows will be driven by arctic air that
will be first surging east southeastward late Tuesday into early Wednesday
across the Northern Plains into the Upper Mississippi Valley and then
eastward trough the Great Lakes into the Ohio Valley on Wednesday. While
there are not expected to be any records with this arctic outbreak,
temperatures will be much below average on Wednesday across the Northern
Plains into the Upper Mississippi Valley. These much below average
temperatures will then push farther southeast into the Great Lakes and
Ohio Valley region on Thursday. Across these regions, high temperatures
will be 10 to 25 degrees below average during the height of the cold
temperatures during Wednesday and Thursday.

In contrast to the wet and cold conditions across portions of the
north-central to eastern U.S., dry condition and milder temperatures are
in store across the West coast, Great Basin and Rockies region. The dry
air, low relative humidities together with the latest episode of Santa Ana
winds across southern California will produce critical to locally extreme
fire weather danger. These fire weather conditions will be most prominent
in the higher terrain areas to the north and east of the Los Angeles to
San Diego region. Winds of 35 to 45 mph in the valleys and gusts of 50 to
65 mph in the mountains will help fan any fires that do develop quickly
and may reduce visibility with blowing smoke and dust adding to travel
concerns in the region. Across these areas, red flag warnings are
currently in effect, affecting nearly 13 million people.

By early on Thursday, the next round of coastal rain and mountain snow is
forecast to reach northern California as the next Pacific cyclone arrives.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Mon Dec 09 2024
Valid 12Z Mon Dec 09 2024 – 12Z Wed Dec 11 2024

…Heavy rain threat across the central to eastern Gulf Coast region today
will expand and move up the East Coast late Tuesday into Wednesday
morning…

…Periods of mixed rain and snow linger across interior New England
through tonight…

…Snow/blizzard conditions across the northern High Plains will gradually
taper off later today…

…Strong Santa Ana winds prompting critical fire danger across Southern
California…

…Well above average temperatures will overspread the central and eastern
U.S. as cold air surges into the western and then central U.S….

Increasingly active weather will progress toward the eastern U.S. through
the next couple of days as a weather pattern reversal continues to unfold
across the mainland U.S. One of the ingredients of this pattern change is
manifested by an expanding area of moderate to heavy rain moving through
the Ohio and Tennessee Valleys this morning with embedded thunderstorms
across the Deep South. The associated jet stream aloft will send the rain
rapidly northeastward across the Mid-Atlantic states today, reaching into
southern New England tonight. Temperatures will be cold enough to support
snow across northern New England Monday night into Tuesday morning before
tapering off for the time-being Tuesday afternoon. Meanwhile, an
extensive surge of cold air into the mid-section of the country will
reinvigorate the jet stream across the Deep South on Tuesday, leading to
an expanding area of moderate to locally heavy rain from the Gulf Coast
into the Deep South and interior Southeast. Tuesday night into Wednesday
morning will likely see the rain quickly expanding up the Appalachians and
into the interior section of the Mid-Atlantic, and then up into New
England with some ice possible at the onset. Meanwhile, organized lines
of thunderstorms could form ahead of a potent cold front across the
interior Southeast early on Wednesday along with sharply colder
temperatures and blustery northwesterly winds behind the front.

Across the northern High Plains, colder air and gale force winds behind a
low pressure system have prompted winter weather advisories/warnings,
Blizzard Warnings, as well as wind advisories/high wind warnings this
morning. 4-7″ of snow is expected across the northern High Plains.
Meanwhile, strong onshore flow off Lake Superior will further enhance
local snow totals across the Arrowhead of MN range where 9-12″+ totals are
expected.

On Tuesday, a more intense surge of cold air will be funneled southward
from Alaska and western Canada into the Plains associated with an
intensifying arctic high pressure system. A ‘Blue Norther’ cold front
will be driving well through the Southern Plains into northern Mexico by
Tuesday night, dropping temperatures into the 30s into southern Texas by
Wednesday morning. Meanwhile, a reinforcing cold front will drop
temperatures below zero degrees over the northern Plains by then. High
temperatures will be about 5-10 degrees below normal across much of the
Rockies, Southwest and eventually into the Plains.

Across the western U.S., a cold surge directed through the Great Basin
into the lower Colorado River Valley today will bring very strong Santa
Ana winds into southern California by later today. Given dry/low humidity
conditions already in place, Red Flag Warnings have been issued for the
eastern Transverse and all of the Peninsular Ranges; as well as a Critical
Fire (level 2 of 3) from the Storm Prediction Center. Winds of 35 to 45
mph in the valleys and gusts of 50 to 65 mph in the mountains will help
fan any fires that do develop quickly and may reduce visibility with
blowing smoke and dust adding to travel concerns in the region.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Sun Dec 08 2024
Valid 12Z Sun Dec 08 2024 – 12Z Tue Dec 10 2024

…Heavy rain threat emerges across the Deep South late Sunday into
Monday…

…Periods of mixed rain and snow linger from the Great Lakes to northern
New England through Monday night…

…Unsettled and windy weather spreading across the Pacific Northwest this
weekend will reach into the northern Plains as snow/wintry mix by Monday…

…Well above average temperatures will overspread the central and eastern
U.S. as cold air surges into the western U.S….

A major reversal of the weather pattern is forecast to occur across
mainland U.S. during the next couple of days. The remaining cold air
across the eastern U.S. originated from the recent arctic outbreak will be
dispelled by an eastward expanding mild air mass from the central U.S.
Meanwhile, the mild air across the western U.S. in recent days will be
dispelled by a surge of cold air currently advancing through the
northwestern U.S. The upper-level trough responsible for this cold surge
into the western U.S. will first spread mixed rain and snow through the
northern Rockies today behind a cold front along with windy conditions.
Daytime heating will keep the precipitation mainly in the form of rain as
it moves quickly across the northern Plains today. By tonight, colder air
from Canada is forecast to filter south from Canada behind a low pressure
system. This will bring periods of snow into the northern Plains and
areas farther west to the foothills of the northern Rockies through
tonight and into Monday, along with windy conditions. The higher elevations
will receive higher amounts of snow, with the highest snowfall likely near
the northern slopes of the Black Hills where more than a foot of new snow
is possible. Portions of the central Rockies into the Front Range of
Colorado and down into northeastern New Mexico can expect to receive a
period of snow from this system through Monday night into Tuesday morning.

Ahead of the cold front trailing south from the aforementioned low
pressure system, a jet stream sliding across northern Mexico will interact
with a coastal front and a low pressure wave near the western Gulf Coast
to bring an increasing threat of heavy rain farther inland across the
lower Mississippi Valley and then into the Deep South through the next
couple of days. Warmer and more unstable air arriving from the Gulf will
help trigger heavier showers and thunderstorms for the eastern portion of
these areas. The overlapping elements coupled with some recent rainfall
will result in the possibility of scattered instances of flash flooding.
The Weather Prediction Center maintains a Marginal Risk of Excessive
Rainfall across the central Gulf Coast region for Monday into early
Tuesday, with a Sight Risk area from southeastern Louisiana to southern
Mississippi.

Across New England, widespread snowfall is in progress today ahead of a
clipper system moving quickly eastward along a warm front lifting north
across the region. Widespread snowfall of up to 6 inches can be expected
from the Adirondacks eastward through Maine before the snow tapers off
tonight. More snow will then skirt the upper Great Lakes ahead of the
warm front associated with the northern Plains low pressure system, with
6-8 inches expected over the Upper Peninsula of Michigan and the Arrowhead
of Minnesota. A period of rain will sweep across the Ohio Valley Sunday
night, then the Appalachians and the northern Mid-Atlantic on Monday ahead
of the trailing front, followed by the next round of snow across northern
New England Monday night. Mild Atlantic air will keep the precipitation
as rain for southern New England into Tuesday morning.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Sat Dec 07 2024
Valid 12Z Sat Dec 07 2024 – 12Z Mon Dec 09 2024

…Periods of mixed rain and snow linger from the Great Lakes to northern
New England through the weekend…

…Heavy rain threat emerges across the Deep South late Sunday into
Monday…

…Unsettled and windy weather spreading across the Pacific Northwest this
weekend will reach into the northern Plains as snow by Monday…

…Arctic air across the eastern U.S. will give way to above normal
temperatures by Monday…

As an arctic high pressure system moderates and retreats across the
eastern portion of the country, unsettled weather will emerge and expand
across the Deep South as well as the Pacific Northwest. Moisture
returning behind the high pressure system today will begin to interact
with an upper-level trough and a coastal front just off the Texas coast.
This will result in expanding areas of light to moderate rain with
embedded thunderstorms across the eastern two-thirds of Texas today. The
entire system will shift northeastward on Sunday before evolving into a
heavy rain threat across the lower Mississippi Valley toward the Tennessee
Valley by late Sunday into early Monday. A couple of inches of rain is
expected in this general vicinity with locally higher amounts through
Monday morning.

Meanwhile, periods of mixed rain and snow are expected to linger across
the Great Lakes and into northern New England where a clipper low pressure
system is forecast to track along a nearly stationary arctic front. Up to
a foot of new snow is possible near the Canadian border in these areas.

The Pacific Northwest is entering a period of increasingly unsettled
weather as a rather dynamic upper trough arrives from the Pacific.
Low-elevation rain and high-elevation heavy snow can be expected for the
Cascades and northern Idaho as the weekend progresses with windy
conditions. The mountain snow and low-elevation rain will progress
farther inland into the northern Rockies early Sunday as a low pressure
system begins to develop across the northern High Plains into Alberta
Province of Canada. Winter Storm Warnings and Advisories are active
across the northern Rockies through Saturday where several inches of
snowfall and some icing potential will create hazardous travel conditions.
Meanwhile, much of the remainder of the western U.S. will remain dry and
milder than normal as high pressure dominates. By Sunday night into
Monday morning, a low pressure system is forecast to track across the
northern Plains with snow and wind. Mainly light snowfall amounts are
expected for North Dakota into Montana, with high amounts enhanced by
local terrains.

Low temperatures in the 20s as far south as the Florida Panhandle this
morning have prompted Freeze Warnings for portions of northern Florida
into Georgia. High temperatures will begin to moderate across the East by
Sunday as anomalously mild temperatures across the central U.S. shift
eastward into the region. Highs should be in the 60s and 70s Sunday across
the Southeast and 50s and 40s across the Mid-Atlantic and Northeast, while
50s and 60s will expand across the northern and central Plains Sunday
afternoon ahead of the developing low pressure system.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Fri Dec 06 2024
Valid 12Z Fri Dec 06 2024 – 12Z Sun Dec 08 2024

…More lake-effect/lake-enhanced snow downwind from Lakes Erie and
Ontario…

…Arctic air currently engulfing much of the eastern U.S. will gradually
moderate over the next couple of days…

…Dry and milder than average temperatures in the western U.S. will
spread into the northern and central U.S. through the next couple of
days…

Under an intense surge of arctic air, Friday morning will begin with the
coldest temperatures so far this season across much of the central and
eastern U.S. with blustery conditions and a piercing wind chill. The
persistent flow of arctic over the relatively warm waters of the Great
Lakes has continued to bring lake-effect snows downwind into the Snow
Belt. By later today into tonight, another clipper currently forming
along the arctic front will spread more snow across the Great Lakes from
northwest to southeast. By Saturday, still another clipper will bring
more widespread snowfall across the upper Great Lakes, reaching into the
lower lakes Saturday night. Milder air could change some of the snow to
rain Saturday afternoon near the western fringe of these areas. As much
as two additional feet of new snow is possible near the eastern shore of
Lake Ontario through the next couple of days. Lighter snowfall amounts
can be expected elsewhere along the Snow Belt.

After a morning with wind chills possibly falling below zero across the
mountains of the Applachains, conditions are expected to improve through
the next couple of days as southwesterly winds begin to bring milder air
from the western U.S. into the northern and central Plains. The most
drastic recovery will be found over the northern High Plains where high
temperatures could top 60 degrees by Saturday afternoon.

The retreating arctic high pressure system that brings the milder air into
the northern U.S. will also bring increasing moisture into Texas. It
appears that rain will expand in coverage across southern to eastern Texas
through Saturday ahead of an upper trough. Additional influx of moisture
from the Gulf of Mexico could begin to raise the threat of heavy rain from
eastern Texas into Louisiana by early on Sunday.

After a tranquil Friday, increasingly unsettled weather is expected for
the Pacific Northwest by the weekend. Rain showers and some high elevation
snow will return to Washington State and Oregon by Saturaday as the next
front moves through. The mountain snow and low-elevation rain will
progress farther inland, reaching into the northern Rockies by early
Sunday as a low pressure system begins to develop across the northern High
Plains into Alberta Province of Canada. Much of the remainder of the
western U.S. will remain dry and milder than normal as high pressure
dominates the region. High temperatures will be in the 80s across the
Southwest while 70s and 60s will prevail from southern California to the
Pacific Northwest.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Thu Dec 05 2024
Valid 12Z Thu Dec 05 2024 – 12Z Sat Dec 07 2024

…Heavy lake-enhanced/lake-effect snow downwind from Lakes Erie and
Ontario on Thursday and Friday; Moderate to heavy snow over parts of New
England on Thursday; light to moderate snow over parts of the Central
Appalachians on Thursday and Friday…

…Light to moderate lake-effect snow for the Upper Peninsula of Michigan
and the west coast of the Lower Peninsula on Thursday and Friday…

…Temperatures will be 10 to 20 degrees below average over parts of the
Ohio Valley and the Mid-Atlantic…

A storm over southeastern Canada will move eastward to far eastern Canada
by Friday morning. The system will produce heavy lake-enhanced then heavy
lake-effect snow downwind from Lakes Erie and Ontario on Thursday and
Friday. Additionally, in the wake of the storm, light to moderate
lake-effect snow will develop over parts of the Upper Peninsula of
Michigan and the west coast of the Lower Peninsula of Michigan on Thursday
and Friday. Further, moderate to heavy snow will be created on Thursday
over parts of New England. By Friday, scattered light snow will be over
New England and then the snow will end by Friday evening. Furthermore,
light to moderate snow will develop over parts of the Central Appalachians
on Thursday and Friday.

Moreover, the strong arctic cold front will sweep across the Mid-Atlantic
and the Northeast on Thursday. The boundary will create snow squalls
accompanied by intense bursts of heavy snowfall and gusty winds, producing
dangerous travel conditions due to whiteouts and icy roads.

In addition, wind gusts up to 50 mph will spread into the Central
Appalachians, Mid-Atlantic, and Northeast on Thursday. These winds may
cause power outages, down tree branches, and result in hazardous commutes.

Moreover, after the storm, high pressure over the Northern Plains will
move southeastward to the Tennessee Valley by Saturday. The high pressure
will usher in cold temperatures over parts of the Ohio Valley and the
Mid-Atlantic, bringing temperatures of 10 to 20 degrees below average.

Meanwhile, return flow off the Gulf of Mexico will create scattered
showers and thunderstorms over parts of the Central Gulf Coast on
Thursday. On Friday, scattered showers and thunderstorms will develop over
parts of the Southern High Plains.

Elsewhere, lingering stagnant air conditions will be over parts of the
Pacific Northwest, leading to areas of dense fog and poor air quality.
However, an approaching front over the Eastern Pacific will usher moisture
into the Pacific Northwest, creating light rain over parts of the
Northwest Coast late Friday night into Saturday.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Wed Dec 04 2024
Valid 12Z Wed Dec 04 2024 – 12Z Fri Dec 06 2024

…Heavy snow for the Upper Peninsula of Michigan and the northern Lower
Peninsula on Wednesday…

…Heavy lake-enhanced snow downwind from Lakes Erie and Ontario on
Wednesday and Thursday; Heavy snow over parts of Northern New England;
light to moderate snow over parts of the Central Appalachians on
Wednesday…

…Temperatures will be 10 to 15 degrees below average over parts of the
Mid-Atlantic and the Southeast…

On Wednesday, high pressure over the Southeast will move southeastward off
the Southeast Coast by Wednesday night. The high pressure will create cold
temperatures over parts of the Mid-Atlantic and the Southeast, bringing
temperatures of 10 to 15 degrees below average.

Meanwhile, low pressure just north of Lake Superior will move eastward to
Southeast Canada by Friday. The storm will produce heavy snow over the
Upper Peninsula of Michigan and the northern Lower Peninsula of Michigan
through Thursday morning. Moreover, heavy lake-enhanced snow will develop
downwind of Lakes Erie and Ontario through Friday. Additionally, heavy
snow will develop over New England through Friday too.

Furthermore, light snow will develop over parts of the Northern
Plains/Upper Mississippi Valley and the Ohio Valley from Wednesday through
Friday. Moderate to heavy snow will develop over parts of the Central
Appalachians through Friday. Rain will also develop over the coastal parts
of New England through Thursday afternoon and then change over to snow.

Moreover, weak return flow off the Gulf of Mexico will create scattered
showers and thunderstorms over parts of the West/Central Gulf Coast
through Wednesday and Thursday. Some of the rain will be moderate to heavy
over parts of the Western Gulf Coast. Therefore, the WPC has issued a
Marginal Risk (level 1/4) of excessive rainfall over parts of the Western
Gulf Coast through Thursday morning. The associated heavy rain will
create localized areas of flash flooding, affecting areas that experience
rapid runoff with heavy rain.

Rain will also expand along the Eastern Gulf Coast into the Southeast on
Thursday and into parts of the Southern High Plains Thursday night into
Friday.

Elsewhere, upper-level ridging will create stagnant air conditions over
parts of the Pacific Northwest, leading to areas of dense fog and poor air
quality. However, an approaching front over the Eastern Pacific will usher
moisture into the Pacific Northwest, creating light rain over parts of the
Northwest Coast late Wednesday night into Friday.