weather

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Thu Jan 16 2025
Valid 12Z Thu Jan 16 2025 – 12Z Sat Jan 18 2025

…Improvement in fire weather conditions across southern California…

…A brief moderation of temperatures across the central U.S. before an
arctic front plunges into the northern U.S. on Friday…

…Lake effect snow expected on Thursday and snow also expected for the
central Appalachians…

There will be a few things making weather headlines through Friday night
across the country. Lake effect snow is expected in the wake of a
shortwave passage, and the heaviest snowfall will be downwind of Lake Erie
across western New York on Thursday, where lake effect snow warnings are
now in effect. Moderate to heavy snow is also on the way for the central
Appalachians with moist upslope flow leading to 5-10 inches of
accumulation across the higher terrain of West Virginia into south-central
Pennsylvania, where winter storm warnings are in effect.

A pattern change will evolve across the Central U.S. and the Rockies going
into Friday and especially into early Saturday. After a brief moderation
in temperatures across the north-central U.S. on Thursday, an abrupt
change to reality is coming by Friday as a pair of strong cold fronts
heralds the arrival of frigid temperatures and brutally cold wind chills.
This will continue well beyond the short range forecast period, and the
Weather Prediction Center has Key Messages regarding this arctic blast.
This could also be accompanied by some snow showers and a few snow squalls
across the northern Rockies and western High Plains going into Friday and
Friday night, resulting in mainly light accumulations but accompanied with
poor visibilities and gusty winds.

For the Eastern U.S., a gradual moderation trend in the recent very cold
conditions is on the way to conclude the work week with readings returning
to near seasonal averages for the East Coast, and above average for much
of the Southeast states. A developing low pressure system over the Deep
South Friday night will likely lead to increasing showers and perhaps a
few thunderstorms near the central Gulf Coast region by Saturday morning,
but this region should remain dry until then.

Things are starting to look better in terms of the forecast across
California and the areas that have been devastated by the ongoing
wildfires. Even though no rain is in the forecast, the winds are expected
to switch to a more onshore flow late Thursday and into Friday, bringing
higher relative humidities and less chaotic wind flow, thus helping to
mitigate the wildfire threat compared to recent days.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Tue Jan 14 2025
Valid 12Z Tue Jan 14 2025 – 12Z Thu Jan 16 2025

…Extremely critical fire weather conditions will continue across coastal
Southern California today…

…Much below average temperatures from the Midwest to the central
Appalachians through Wednesday but warming into the central U.S. on
Thursday…

…Locally heavy lake effect snow showers downwind of the Great Lakes
through Wednesday…

Overall, the weather pattern across most of the lower 48 through Thursday
will feature a lack of precipitation with a warming trend later in the
week. This will be a reflection of broad upper level troughing over the
eastern two thirds of the nation and ridging over the Pacific Northwest,
forecast to migrate eastward through Thursday.

Coastal southern California will continue to see extremely critical fire
weather conditions through at least today with localized wind gusts near
70 mph focused across Ventura and Los Angeles counties. Very dangerous
conditions will continue into Wednesday for many of these same locations
with a broader, though not as extreme, threat extending along most of the
Transverse and Peninsular Ranges. Winds are expected to oscillate in
magnitude over the next 48 hours but the environment is expected to be
remain extremely dangerous, favorable to very rapid fire growth if a fire
does start.

After the passage of a cold front on Monday night across the eastern U.S.,
another surge of modified Arctic air will move across the Midwest today.
High temperatures will be 10 to 20 degrees below average for many
locations from the Upper Midwest through the Ohio Valley today, with the
cold continuing for the Ohio Valley on Wednesday. A change in wind
direction from northerly/northwestelry to westerly will accompany a warm
front on Wednesday across the north-central U.S. which will have the
effect of significant warming for the region. In fact, high temperatures
are forecast to jump about 20 degrees higher on Wednesday compared to
Tuesday for the north-central U.S., moving high temperatures from below
average to above average. The warmer weather will expand south and east
for Thursday but the East Coast will still remain a little below average.

The other consequence of the cold weather will be heavy lake effect snow
showers on the southeast and eastern shores of the Great Lakes. While
local wind direction will vary over the next couple of days, moving narrow
bands of heavy snow north or south, the heaviest accumulations of 1 to 2
feet (locally higher) are expected east of Lake Erie and Lake Ontario,
especially into the Tug Hill Plateau.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Mon Jan 13 2025
Valid 12Z Mon Jan 13 2025 – 12Z Wed Jan 15 2025

…Extremely dangerous fire weather conditions to develop across coastal
southern California early this week…

…Locally heavy lake effect snow showers downwind of Lakes Erie and
Ontario as renewed surge of arctic air moves through into the upper
Midwest and Ohio Valley…

The weather pattern across the lower 48 will feature upper level ridging
from the northeastern Pacific into the northwestern U.S., while upper
level troughing dominates much of the remaining area of the country. Below
average moisture across much of the lower 48 will result in a lack of
rain/snow for many areas of the lower 48 through Tuesday with the
exception of lake effect snow showers and scattered snow showers in and
around the northern/central Rockies into the High Plains.

The passage of a weak surface low and cold front through Florida today
will bring a gradual end to rainfall across portions of the southeastern
U.S. Meanwhile, another cold front, moving through the Ohio Valley this
morning, will be followed by another surge of Arctic air which will reach
the Midwest today and into the Mid-Atlantic and Northeast for Tuesday. The
cold front will be accompanied by snow showers today across the Northeast
with potential for isolated snow squalls which could result in hazardous
travel from sudden reduced visibilities, gusty winds and quick minor
accumulations of snow. High temperatures will be 10 to 20 degrees below
average today from the Upper Midwest to lower portions of the Ohio Valley.
The airmass will be modifying/losing vigor as it reaches the East Coast,
but will still be responsible for below average temperatures by Tuesday
for the Eastern Seaboard. Heavy lake effect snow showers are expected to
develop later today as the colder air moves across the Great Lakes, with
localized snowfall accumulations of 1-2 feet for isolated locations which
experience persistent banding through Tuesday night, mainly east of Lake
Erie and Lake Ontario.

The lack of precipitation across the CONUS will also include southern
California which has experienced a number of high profile wildfires over
the past week. Upper troughing aloft and increasing surface pressures over
the Great Basin will again lead to strong gusts across the typically
favored areas across coastal southern California today with winds peaking
between 40-50 mph. Conditions are expected to worsen for these locations
by Tuesday morning as wind gusts near 70 mph will be possible. When
combined with low relative humidities and a lack of recent rainfall (dry
fuels), a Particularly Dangerous Situation Red Flag Warning has been
issued for Santa Barbara, Ventura and Los Angeles Counties from Monday
night through Wednesday morning. These locations will be under a high risk
for large fires with potential for very rapid spreading of any fires that
may develop.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Sun Jan 12 2025
Valid 12Z Sun Jan 12 2025 – 12Z Tue Jan 14 2025

…Critical fire weather conditions will continue for southern California
into early this week…

…Clipper system to bring snow showers to the Great Lakes along with
renewed surge of Arctic air to the Upper Midwest and Ohio Valley…

…Rain for the central Gulf Coast today and Georgia/Florida on Monday…

Snow showers that were ongoing early Sunday morning from the northern
Great Basin into the northern and central Rocky Mountains will begin to
taper off today as a surface low tracks toward the Great Lakes region.
Snow showers will linger through Monday from parts of Montana into the
High Plains near a strong frontal boundary but snowfall intensity will be
decreased compared to what occurred Saturday/Saturday night.

The surface low moving into the Great Lakes will have a trailing cold
front that will sweep across the Ohio Valley by Monday morning, bringing a
renewed surge of Arctic air in its wake. High temperatures that are only
in the single digits and teens will affect the northern Plains today with
the cold, clipper-like system continuing eastward through Tuesday morning
with high temperature departures of 10 to 20 degrees from normal following
in its wake, reaching the Midwest on Monday and East Coast for Tuesday.
Snow showers will likely track with the front as it moves east across the
Upper Ohio Valley into the Northeast on Monday, briefly reducing
visibilities.

Fire weather concerns will remain across coastal locations of southern
California today with winds gusting between 30-50 mph early this morning.
Weakening winds are expected into this afternoon/evening as the pressure
gradient weakens across the region. However, a resurgence of gusty winds
is forecast Sunday night into Monday across southern California as
mid-level impulses sink south across the western U.S., allowing for a
re-tightening of the surface pressure gradient and gusty
downslope/offshore winds.

For the Gulf Coast, an area of low pressure will form along a remnant
frontal boundary over the open Gulf waters Sunday night and track toward
the central Gulf Coast. Rain will increase in coverage late this morning
across the upper Texas coast into southern Louisiana and steadily move
east through Sunday night. By Monday morning, rain will be affecting the
Florida Panhandle into portions of southern Alabama/Georgia but rainfall
intensity will diminish throughout the day on Monday. While some light
rain may continue over Florida near a frontal boundary Tuesday morning,
much of the U.S. will see relatively quiet weather.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Sat Jan 11 2025
Valid 12Z Sat Jan 11 2025 – 12Z Mon Jan 13 2025

…A return to dangerous fire weather concerns for southern California
beginning later today…

…Moderate to locally heavy snow for the parts of the northern to central
Rockies…

…Below average high temperatures for much of the lower 48 this weekend
after departure of southern Mid-Atlantic winter storm…

A significant winter storm that brought widespread impacts to much of the
South over the past couple of days will quickly move away from the East
Coast this morning, leaving light snow showers in its wake for the central
Appalachians and New England. High pressure and quieter weather will
settle into locations east of the Mississippi River through Sunday morning
but more rain is expected for the central Gulf Coast Sunday into Monday as
low pressure organizes in the Gulf of Mexico, sending anomalous moisture
northward. Temperatures will be cold today for the southern/southeastern
U.S. with high temperature departures running 10 to 20 degrees below
average. Below average temperatures will also extend into the Midwest,
Ohio Valley and Northeast but Maine will be close to average for
mid-January. Some moderation of the cold temperatures will occur for
Sunday for the South and East, except for New England which will be near
to above average.

Out West, an upper level trough will continue to advance eastward from the
central Rockies today with moderate to locally heavy snow showers
continuing through Saturday night for northern sections of the Great Basin
and northern/central Rockies in its wake via northwesterly to northerly
flow behind the upper trough axis. Snow will continue near a strong
frontal boundary in central Montana on Sunday but subside elsewhere across
much of the West. By Monday morning, localized snowfall accumulations of 1
to 2 feet are expected for portions of central and southern Montana into
the Big Horn Mountains of Wyoming.

High Temperatures across the West will generally be below average this
weekend while temperatures along the West Coast remain near average
through the weekend. The exception to colder than average high
temperatures for the lower 48 will be in and around the Upper Great Lakes
which will lie on the warm side of low pressure tracking across the
north-central U.S. with colder air filtering into the region behind the
low on Monday.

In southern California, a return to heightened fire weather conditions
will return later today after a brief lull from Friday night. High
pressure will increase across the Great Basin today as a surge of colder
air moves into the region behind a cold front which is forecast to move
into Mexico Sunday morning. Gusty offshore winds along the coast of
southern California support a Critical Risk area for Saturday as
highlighted by the Storm Prediction Center, with these dangerous
conditions continuing into Monday.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Fri Jan 10 2025
Valid 12Z Fri Jan 10 2025 – 12Z Sun Jan 12 2025

…Critical fire weather conditions will continue across Southern
California through at least this morning…

…A significant winter storm will continue to bring heavy snow and
disruptive ice across much of the South through Saturday morning…

…Pacific Storm to bring lower elevation rain/mountain snow to the
Pacific Northwest…Great Basin and Rockies through Saturday…

Modified arctic air combined with a moisture-laden area of low pressure
along the Gulf Coast will continue to allow for a broad area of winter
weather impacts from the Lower Mississippi Valley to the Southeast today
into early Saturday morning. Areas of light to moderate snow will
translate east from eastern Oklahoma, southern Missouri and Arkansas this
morning into and across the Tennessee Valley, eventually reaching the
Mid-Atlantic region tonight. Snowfall accumulations of 4 to 8 inches are
expected from near Memphis into the central Appalachians. Sleet and
freezing rain will affect locations just south of the snowfall, with ice
accumulations locally in excess of 0.25 inches from far northeastern
Alabama into northern Georgia and upstate South Carolina. Light snowfall
accumulations (1 to 3 inches) are anticipated farther north from the Ohio
Valley into northern portions of the Mid-Atlantic region. Below average
temperatures from the south-central to southeastern U.S. will moderate
into the weekend but remain roughly 5 to 15 degrees below average on
Saturday into Sunday.

Across the western U.S., strong high pressure over the Great Basin will
begin to weaken during the day today, but Critical fire weather conditions
will continue over coastal locations of Southern California through the
remainder of this morning with localized gusts to near 60 mph. While wind
gusts are likely to weaken into this afternoon and evening, remnant gusty
winds and low relative humidities will continue dangerous conditions into
the afternoon and evening.

Elsewhere across the western U.S., a quick moving cold front will sweep
across the Northwest and Great Basin today, bringing coastal rain to the
Pacific Northwest and mountain snow to the Cascades, northern Great Basin
into the northern and central Rockies. Low pressure associated with the
western U.S. storm system will reach the northern Plains and Upper Midwest
on Saturday/Saturday night, resulting in light (1 to 3 inch) accumulations
for eastern Montana, North Dakota into the Upper Mississippi Valley.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Thu Jan 09 2025
Valid 12Z Thu Jan 09 2025 – 12Z Sat Jan 11 2025

…Decreasing light lake-effect snow downwind from the Lower Great Lakes
on Thursday…

…A developing Winter Storm will produce snow and rain/freezing rain,
icing, over parts of the Southern Plains and Lower Mississippi Valley on
Thursday and over the Lower Mississippi Valley to the southern
Mid-Atlantic on Friday…

…Light snow over parts of the Upper Midwest on Thursday; Light to
moderate snow over the Great Lakes/Ohio Valley and light snow over parts
of the Northeast on Friday…

…There is a Critical Risk of fire weather over parts of Southern
California on Thursday…

A developing winter storm will move out of Northern Mexico, advancing
eastward to the Western Gulf Coast by Thursday evening and to the Central
Gulf Coast by Friday morning. The storm will move northeastward to western
Florida by Friday evening and to the southern Mid-Atlantic Coast by
Saturday.

The system will produce a swath of heavy snow along with ice, freezing
rain, from the Southern Plains to the southern Mid-Atlantic by Saturday.
Snowfall totals from 6-8 inches will develop from southeast Oklahoma
through western North Carolina. A quarter inch of ice, freezing rain, will
occur from the Southern Plains to the Lower Mississippi Valley. On Friday,
icing, freezing rain, will move over parts of the Southeast, Southern
Appalachians, and southern Mid-Atlantic, with amounts around a tenth of an
inch.

A large area of moderate winter weather impacts will be associated with
the storm. Some impacts are widespread closures, treacherous travel,
scattered power outages, and downed branches expected from the Red River
Valley and southern Ozarks through the Lower Mississippi Valley, Tennessee
Valley, and Southern Appalachians. Some of the heaviest snowfall will be
over the Tennessee Valley, which will be 6 inches on Friday.

Meanwhile, on Thursday, strong high pressure over parts of the Northern
Intermountain Region and Great Basin will set up Santa Ana winds over
Southern California. Therefore, the SPC has issued a Critical Risk of fire
weather over parts of Southern California. Winds of 20 to 40 mph, with
stronger winds in the terrain, low relative humidity, and dry fuels have
contributed to the dangerous conditions.

Moreover, on Thursday, exiting upper-level energy and developing weak
upper-level ridging over the Great Lakes will create waning light
lake-effect snow and upslope snow over parts of the Lower Great Lakes and
the Northeast that will end by Friday morning.

Furthermore, upper-level energy over the Northern Intermountain Region
southward to the Southwest will develop a front extending from the
Northern/Central Plains to the Southern Rockies that will move eastward to
the Upper Great Lakes to the Southern Plains by Friday morning. The
boundary will begin to dissipate by Friday evening. However, the
associated upper-level trough will extend from the Great Lakes
southwestward to Northeastern Mexico by Saturday.

On Thursday, the system will produce light snow over parts of the Upper
Midwest to the Central Plains/Middle Mississippi Valley. In addition, on
Friday, the boundary will deliver light to moderate snow over parts of the
Great Lakes/Ohio Valley and Central Appalachians. Additionally, light snow
will develop over parts of the Northeast.

In the meantime, overnight Thursday, a new front will move onshore over
the Pacific Northwest and race eastward to the Northern Plains to the
Great Basin by Saturday. The system will trigger coastal rain and
higher-elevation snow over parts of the Pacific Northwest on Friday and
overnight Friday moderate to heavy snow over parts of the Northern
Intermountain Region. By Saturday, the light to moderate snow will expand
into parts of the Northern/Central Rockies and Great Basin.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Wed Jan 08 2025
Valid 12Z Wed Jan 08 2025 – 12Z Fri Jan 10 2025

…Moderate to heavy lake-effect snow downwind from the Great Lakes on
Wednesday…

…A developing Winter Storm will produce snow and rain/freezing rain,
icing, over parts of the Southern Plains and Lower Mississippi Valley late
Wednesday night into Thursday…

…Light to moderate snow over parts of the Northern Rockies/Northern
Plains and Southern Rockies/Southern High Plains on Wednesday: Light snow
over parts of the Upper Midwest on Thursday…

…There is an Extremely Critical Fire Weather Area for portions of the
Southern California Coast…

Cold high pressure extending from the Central Plains to western Ontario,
Canada, moves to the Mid-Atlantic by Friday. The cold air and upper-level
energy will aid in producing moderate to heavy lake-effect snow downwind
from the Great Lakes on Wednesday and will begin to taper off on Thursday.
In addition, moderate to heavy upslope snow will develop over parts of
the Northeast, and light to moderate upslope snow over the Central
Appalachians will develop on Wednesday.

Meanwhile, strong high pressure over parts of the Great Basin and low
pressure dropping into the Gulf of California will continue to support
Santa Ana winds and a dangerous fire weather event over portions of
Southern California on Wednesday. The SPC has issued a Extremely Critical
Fire Weather Area along portions of the Southern California Coast.
Sustained winds reaching 30 to 40 mph, with stronger winds in the terrain,
along with low relative humidity, and dry fuels will contribute to the
dangerous conditions. Critical fire weather conditions are expected to
continue on Thursday for portions of Southern California.

Moreover, on Wednesday, a deep upper low over Northwestern Mexico will
open and move to the Southern Rockies to the Southern Plains by Friday.
The system will create impactful winter weather on Thursday for portions
of the Southern Plains before intensifying as it expands across the Lower
Mississippi Valley overnight Thursday into Friday. Snowfall totals will be
the greatest, 4 to 8 inches, from portions of North Texas across Arkansas
into the Tennessee Valley. Hazardous driving conditions can be expected
through the swath of winter weather. Additionally, rain/freezing rain will
develop over parts of Central Texas into southern Arkansas and northern
Louisiana. Over this region, scattered ice amounts of 0.10 inches will
fall on Thursday.

Furthermore, additional upper-level energy will move over the Pacific
Northwest/Northern Intermountain Region Wednesday morning and reach the
Southern Rockies and the Upper Great Lakes by Friday. The energy will aid
in the development of a new front over the Northern/Central Plains into
the Central Rockies that will move eastward to the Upper Great Lakes to
the Southern Plains by Friday.

The new energy will create a short-lived light coastal rain and
higher-elevation snow over parts of the Pacific Northwest on early
Wednesday morning. By Wednesday evening, light snow will develop over
parts of the Northern Rockies, expanding into parts of the Northern Plains
and Central Rockies by Thursday morning. By Thursday night, light snow
will extend from the Northern Plains/Upper Mississippi Valley to the
Central/Southern Rockies and Central/Southern Plains. By Friday morning,
the light snow will move into the Upper Great Lakes and Middle Mississippi
Valley, while continuing over the Southern Plains.

Moreover, by Friday, a new front moving onshore over the Pacific Northwest
will trigger coastal rain and higher-elevation snow over parts of the
Pacific Northwest.