Sig Silber

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Fri Jan 03 2025
Valid 12Z Fri Jan 03 2025 – 12Z Sun Jan 05 2025

…Heavy lake-effect snow downwind from Lakes Erie and Ontario; Moderate
to heavy lake-effect snow downwind from the Upper Great Lakes…

… Moderate to heavy snow or the Cascades, Sierra Nevada Mountains, and
the higher elevation of the West; 0.1 inches of freezing rain over parts
of the Central Plains/Middle Mississippi Valley on Saturday…

…Moderate to heavy rain over parts of Pacific Northwest and Northern
California on Friday…

Cold high pressure over the Plains will slowly move eastward to the
Southeast/Central Appalachians by Sunday. The cold air and upper-level
energy over the Great Lakes and Northeast will create heavy lake-effect
snow downwind from Lakes Erie and Ontario through Sunday. In addition,
moderate to heavy lake-effect snow will develop downwind from the Upper
Great Lakes through Sunday, too. Furthermore, moderate to heavy upslope
snow will develop over parts of the Central Appalachians on Friday.

Meanwhile, a front over the Eastern Pacific will move onshore over the
West Coast and move southeastward to the Southern Plains by Sunday.
Moisture associated with the system will produce moderate to heavy rain
over parts of the Pacific Northwest and Northern California on Friday.
Snow will develop over parts of the Cascades, Northern Intermountain
Region, and Northern Rockies. By early afternoon, the boundary will pass
the Northwest and California, rain will change over to snow over the
Southern Cascades into the Sierra Nevada Mountains through Saturday
morning.

A weakening front will move close to the Pacific Northwest Coast by late
Saturday morning and dissipate by Sunday. The system will bring more
coastal rain and higher�elevation snow over parts of the Pacific
Northwest and Northern California through Sunday.

Furthermore, by Saturday afternoon, the lead front will move to the
Southern High Plains and into the Southern Plains by Sunday. The storm
will produce significant wintry weather, with impacts over the Central
Plains by late Saturday and the Ohio and Tennessee Valleys on Sunday.
Additionally, the storm will create severe travel disruptions.

Moreover, areas in the Central Plains and Central Mississippi Valley,
especially along and north of Interstate 70, are likely to experience
heavy snowfall, with a high chance (60-90 percent) of at least 6 inches of
snow from late Saturday into Sunday. Significant sleet and freezing rain
are anticipated from eastern Kansas and the Ozarks extending eastward to
the Tennessee and lower Ohio Valleys, also on Saturday into Sunday.

Further, rain will develop over parts of the Southern Plains/Lower
Mississippi Valley overnight Saturday, and some areas of showers and
thunderstorms will develop by Sunday morning.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Thu Jan 02 2025
Valid 12Z Thu Jan 02 2025 – 12Z Sat Jan 04 2025

…Long duration lake-effect snow event continues downwind of the Great
Lakes…

…Periods of locally heavy coastal rains and higher elevation snow
continue for much of the northwestern U.S….

…Arctic air surges south from the Northern Plains through the Central
and Eastern U.S….

Strong northwesterly winds on the backside of a departing low pressure
system that is moving into the Canadian maritime will generate moderate to
heavy lake enhanced snow downwind of the Great Lakes over the next few
days. Anywhere between 6-12 inches of snow with isolated higher amounts
may accumulate downwind of the Lakes by Saturday morning. A low pressure
system tracking across the Central U.S. will produce a light swath of
snowfall from Iowa across the Ohio Valley today and into the Central
Appalachians on Friday. Snowfall accumulations of 6-12 inches are possible
over the Central Appalachians.

A series of low pressure systems will generate rain and high elevation
snow across much of the Northwest over the next couple of days. The
moisture plume associated with the first system will be directed at the
northern California coast and Oregon today, where an isolated threat of
Flash Flooding exists. Snow showers continue over the Northern/Central
Rockies. Rain and snow showers expand in coverage across the Northwest on
Friday. Accumulating snow is possible over the highest elevations of the
Cascades, Sierra and Northern Rockies. Heavy rainfall expands into the
upslope areas of the Sierra as the cold front pushes through.

High pressure builds over the Great Plains, sending frigid arctic air down
through the Central and Eastern U.S. through the weekend. Meanwhile, the
West and Southern Plains will experience above average temperatures. There
also continues to be an elevated fire weather threat over parts of
southern California today.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Tue Dec 31 2024
Valid 12Z Tue Dec 31 2024 – 12Z Thu Jan 02 2025

…Cooling trend spreads from West to East this week….

…Fire Weather concerns for portions of southern California and Texas
through mid-week…

Systems moving by the northern Intermountain West bring the promise of
snowy periods in and near western Montana, Idaho, and Wyoming through
Wednesday. The first of those systems moves out into the Midwest, Ohio
Valley, and Northeast, bringing rain and thunderstorms near and to the
cyclone’s east, with thunderstorms most likely across portions of the
Eastern Shore and New Jersey on the afternoon and early evening of New
Year’s Eve. As the cyclone moves through the Northeast on Wednesday, both
Lake Effect and Lake Enhanced snows will spread through the Great Lakes
and into the northern and central Appalachians. Between 6-12 inches of
snow are forecast to accumulate downwind of the Lower Great Lakes by
Thursday morning. Some mixed precipitation is expected across central New
England.

A system arriving from the Great Plains will promote snow showers for the
broader Great Lakes region on Tuesday. A cooling trend started in the
West expands east through the rest of the country over the next couple of
days. Building high pressure across the Great Basin is expected to
increase winds across southern California over the next couple of days,
promoting an increased fire weather risk which could become critical
through mid-week. Wind advisories, a red flag warning, and a fire weather
watch have all been posted for the area as well for parts of south-central
Texas through Tuesday.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Mon Dec 30 2024
Valid 12Z Mon Dec 30 2024 – 12Z Wed Jan 01 2025

…Snow showers likely across parts of the Northern Rockies and
Northern/Central Plains today…

…Much above average temperatures continue for the Central and Eastern
U.S today; cooling trend spreads from West to East this week….

…Critical Fire Weather expected for portions of the Southern High Plains
today...

A surface low pressure system ejecting out of the Rockies into the Plains
will likely produce a swath of snow and strong winds from northern Idaho
down through western Iowa today. Moderate impacts mainly due to blowing
snow are expected across much of Wyoming, the Colorado Rockies, South
Dakota and northwestern Nebraska. Snow over the Northern Rockies could
accumulate between 6-12 inches with isolated higher amounts possible. Snow
and wind should subside across the Northwest tonight as the low pressure
system tracks into the Ohio Valley.

Downstream, another, deeper mid-latitude cyclone will spread showers and
scattered thunderstorms into the Northeast with some light snow showers
possible downwind of the Lower Great Lakes today. The arrival of the
Plains system will promote even more snow showers for the broader Great
Lakes region on Tuesday.

Much above average temperatures are expected to continue across the
Central and Eastern U.S. today ahead of their respective low pressure
systems. Temperatures over south Texas will be especially anomalous with
highs likely between 20-30 degrees above average. Numerous high
temperature records may be tied or broken as a result. Unusually mild
conditions in the Northeast may also tie or break high temperature records
today. A cooling trend ensues across the West today before expanding east
through the rest of the country over the next couple of days. A Critical
Fire Weather area was issued by the Storm Prediction Center for much of
the Southern High Plains for today due to the especially warm temperatures
paired with dry and gusty westerly downslope flow beneath the storm to the
north.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Sun Dec 29 2024
Valid 12Z Sun Dec 29 2024 – 12Z Tue Dec 31 2024

…Atmospheric river to produce heavy rain/snow across much of the
Northwest today…

…Severe Thunderstorms and Excessive Rainfall concerns shift into parts
of the Central/Southern Appalachians and Mid-Atlantic/Southeast today…

…Much above average temperatures continue across the Central and Eastern
U.S.; cooler air moves into the Northwest on Monday…

…Critical Fire Weather expected for portions of the Southern High Plains
on Monday…

An active weather pattern will continue in the northwestern and
southeastern quadrants of the country today. Heavy rain associated with an
atmospheric river event will produce 1-2 inches over coastal areas of
Oregon and northern California, including upslope areas of the northern
Sierra Nevada. Slight Risks of Excessive Rainfall (at least 15%) leading
to Flash Flooding are in effect for portions of southwest Oregon/northwest
California and the northern Sierra today. This wet pattern in the West
could produce rock, mud and land slides over vulnerable soils. Additional
heavy snow is likely over much of the Cascades, Northern/Central Rockies
and Sierra Nevada. Between 1-2 feet of snow (isolated higher) are expected
for parts of the Cascades and Rockies.

Storms associated with a severe weather outbreak that occurred across the
Southern Plains and Lower Mississippi Valley yesterday will spread into
the southeastern U.S. today. Heavy rain and scattered to severe
thunderstorms, capable of producing tornadoes, damaging wind gusts and
hail are possible from the eastern Gulf Coast northward into the
Carolinas, where a Slight Risk of Severe Thunderstorms (level 2/5) is in
effect. Rain showers will also spread into the Northeast today as well,
while some light wintry precipitation develops over parts of the Lower
Peninsula of Michigan tonight.

Meanwhile, ongoing moderate to heavy rainfall along a narrow axis of low
level convergence may persist into this afternoon over south Florida.
There’s potential for this Marginal Risk (at least 5%) of Excessive
Rainfall to over perform given current conditions.

Much above average temperatures from the Central to Eastern thirds of the
country should persist until Tuesday, while an increasingly trough-y
pattern in the West will promote cooling temperatures beginning on Monday.
Widespread high minimum temperatures may be tied or broken across the
Northeast tonight ahead of a deepening upstream trough and southerly flow
along a strong surface warm front. Dry, windy and mild conditions in the
Southern High Plains will support a Critical Risk of Fire Weather on
Monday.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Thu Dec 26 2024
Valid 12Z Thu Dec 26 2024 – 12Z Sat Dec 28 2024

…Continued rounds of heavy rain and mountain snow for the Pacific
Northwest…

…Heavy rain and strong thunderstorms return for eastern Texas into
Louisiana on Thursday…

…Relatively mild conditions across the majority of the country through
Friday…

The very active storm track across the eastern Pacific and into the
Pacific Northwest will continue to make weather headlines through the end
of the week. The next in a series of atmospheric river events is now
ongoing across the Pacific Northwest, with moderate to heavy rainfall and
a few thunderstorms continuing into Thursday morning. This round will
likely result in widespread 1 to 3 inch rainfall totals, and there may be
some instances of flooding where rainfall rates are highest. Once this
first system moves inland, there will be a short-lived break Thursday
afternoon before the next round arrives Thursday night for many of the
same areas, bringing an additional 1-2 inches of rain by Friday morning.
Strong and potentially damaging winds are also expected near the coast and
the coastal waters given a strong low level jet with these storm systems.
The Cascades and the Olympic Mountains will get hammered with heavy snow
on the order of 1-3 feet, where winter storm warnings are in effect, and
lighter snows heading south into northern California with winter weather
advisories. The higher terrain of the northern Intermountain West and the
Northern Rockies will also get noteworthy snowfall as moisture from this
storm system moves inland.

Unsettled weather conditions are also expected for portions of the
south-central U.S. going into Thursday, with an amplifying upper trough
developing a new surface low and moisture plume from the western Gulf,
heralding the development of scattered to widespread showers and
thunderstorms. Both wind shear and instability parameters appear to
become increasingly favorable for some severe weather on Thursday, and
therefore the Storm Prediction Center has portions of the ArkLaTex region
in a Slight Risk for severe storms. Heavy rainfall could also be an issue
where these storms train over the same areas, and there is a Slight Risk
of flash flooding from eastern Texas to central Arkansas. An axis of
heavy rain is likely across portions of the Mid-South going into Friday as
the storm system slowly moves eastward.

Elsewhere across the country, mainly dry conditions are forecast across
the Desert Southwest, Northern Plains, and the Northeast U.S. to close out
the week. Foggy conditions are once again likely across portions of the
Midwest and the Central Plains Thursday and Fridays mornings with
warm/moist air advection over cold ground. In terms of temperatures,
forecast highs Thursday and Friday generally range from the 30s and 40s
for the northern Rockies/Plains eastward to the Great Lakes and New
England/Mid-Atlantic; the 40s and 50s for the Pacific Northwest and
northern California eastward across much of the Intermountain West,
central Rockies/Plains, and extending eastward to the Ohio Valley; the 50s
and 60s for the Mid-South and the Southeast U.S. states; and the middle
60s to near 80 degrees for southern California, the Desert Southwest, much
of Texas, and Florida.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Wed Dec 25 2024
Valid 12Z Wed Dec 25 2024 – 12Z Fri Dec 27 2024

…Continued rounds of heavy rain and mountain snow for the Pacific
Northwest…

…Heavy rain and strong thunderstorms return for eastern Texas into
Louisiana on Thursday…

…Relatively mild conditions across the majority of the country through
Thursday…

The very active storm track across the eastern Pacific and into the
Pacific Northwest will continue to make weather headlines through
Thursday. After a brief break in the action, steady rainfall reaches the
Washington and Oregon coasts by midday Christmas, and then reaches
northern California by evening. Periods of heavy rainfall are likely
Wednesday night as the atmospheric river intersects the coastal terrain,
with perhaps a few thunderstorms. This round will likely result in
widespread 1 to 2 inch rainfall totals, and potentially more on the west
facing slopes, and there may be some instances of flooding where rainfall
rates are highest. Once this first system moves inland, there will be a
short-lived break Thursday afternoon before the next round arrives
Thursday night for many of the same areas, bringing an additional 1-2
inches of rain by Friday morning. Strong winds are also expected near the
coast and the coastal waters given a strong low level jet with these storm
systems. Snow levels are likely to be lower with the second round, with
the Cascades getting hammered with heavy snow on the order of 1-3 feet,
and lighter snows heading south into northern California. The higher
terrain of the northern Intermountain West and the Northern Rockies will
also get noteworthy snowfall, particularly across eastern Oregon and into
Idaho.

Unsettled weather conditions are also expected for portions of the
south-central U.S. with a loitering surface low over Texas and a
meandering stationary front over eastern Texas and into Louisiana. There
will likely be a decrease in the shower and thunderstorm coverage on
Christmas Day, but an amplifying upper trough will develop a new surface
low and moisture plume from the western Gulf, heralding the development of
scattered to widespread showers and thunderstorms. Both wind shear and
instability parameters appear to become increasingly favorable for some
severe weather on Thursday, and therefore the Storm Prediction Center has
portions of the ArkLaTex region in a Slight Risk for severe storms. Heavy
rainfall could also be an issue where these storms train over the same
areas, and there is a Slight Risk of flash flooding from eastern Texas to
central Arkansas.

Elsewhere across the country, mainly dry conditions are forecast across
the Desert Southwest, Northern Plains, and most of the East Coast states
with the exception of some showers near the Florida East Coast. Foggy
conditions are likely across portions of the Midwest and the Central
Plains both Christmas morning and Thursday morning with warm air advection
over cold ground. In terms of temperatures, forecast highs on Christmas
Day and Thursday generally range from the 30s and 40s for the northern
Rockies/Plains eastward to the Great Lakes and New England/Mid-Atlantic;
the 40s and 50s for the Pacific Northwest and northern California eastward
across much of the Intermountain West, central Rockies/Plains, and
extending eastward to the Ohio Valley; the 50s and 60s for the Mid-South
and the Southeast U.S. states; and the 60s and 70s for southern
California, the Desert Southwest, Texas, and Florida.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Tue Dec 24 2024
Valid 12Z Tue Dec 24 2024 – 12Z Thu Dec 26 2024

…Heavy rain and mountain snow returns to the West Coast region Wednesday
night…

…Showers and thunderstorms developing over portions of the south-central
states…

…Relatively mild conditions across the majority of the country leading
up to Christmas…

An active weather pattern is expected to continue across the West Coast
region as an energetic storm track across the eastern Pacific brings in
multiple rounds of precipitation. The next in a series of atmospheric
river events is arriving across northern California and western Oregon
late tonight and continuing into Tuesday afternoon. Although the storm
system will be progressive overall, there will be a deep surge of moisture
ahead of the cold front that will intersect the coastal terrain and the
western slopes of the northern Sierra Nevada. Rainfall totals on the
order of 2-4 inches, and locally higher, are likely across this region
through Tuesday evening. Snow levels will be initially high, but should
fall some once the front passes. The heaviest snow from this event should
affect the highest terrain of the central Sierra Nevada, with up to a foot
of accumulation possible, affecting travel through the mountain passes.
Winter weather advisories and winter storm warnings are currently in
effect for this event. After a brief break on Christmas Day, the next
round of moisture moves in towards the West Coast and brings another
substantial round of rain and mountain snow, along with windy conditions
as the pressure gradient tightens in response to a very intense surface
low off the coast of British Columbia.

A relatively weak low pressure system crossing the Northeast U.S. region
on Tuesday will produce light to occasionally moderate snow from the
central Appalachians to New England, increasing the odds of a White
Christmas across this region, especially when combined with existing snow
cover from recent snowfall. This system quickly exits offshore by Tuesday
evening. Farther to the south across Texas, a separate surface low
develops, and increasing southerly flow from the western Gulf of Mexico
ahead of that system will fuel the development of scattered to numerous
showers and some thunderstorms, mainly from eastern Texas northward across
much of Arkansas and into southern Missouri through Christmas morning.
Some locations may get over an inch of rainfall with this event, and thus
a Marginal Risk of excessive rainfall is valid for these areas.

Much of the East Coast region will have a moderation trend in the cold
temperatures going into Christmas Eve, as the arctic surface high moves
offshore and milder air from the Ohio Valley advects eastward across the
region. The remainder of the country should enjoy generally above average
temperatures by late December standards, particularly across the central
and southern Plains where daytime highs could be 15-20 degrees above
average. This would equate to highs well into the 60s and 70s for much of
Texas.