Atmospheric Rivers

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Sun Mar 17 2024
Valid 12Z Sun Mar 17 2024 – 12Z Tue Mar 19 2024

…Locally heavy snow continues across the Southern Rockies today, while
lake effect snow impacts the Great Lakes region through early this week…

…Strong cold front ushers in frost/freeze potential throughout the
Southeast by Tuesday…

…Scattered showers and thunderstorms forecast across the Gulf Coast
States this St. Patrick’s Day…

Even as the Spring Equinox approaches this Tuesday, winter weather
continues to impact parts of the Nation with localized heavy snow. The
same closed upper low that has lingered over the Southwest over the last
few days is expected to continue producing areas of heavy mountain snow
throughout the Southern Rockies and Four Corners region today before the
system weakens and precipitation becomes widely scattered. The heaviest
remaining snow is expected over the mountainous terrain of New Mexico,
which could lead to treacherous travel at times. Meanwhile, a potent low
pressure system crossing from southern Ontario to southern Quebec, Canada
today will aid in lake effect snow downwind of the Great Lakes through
early this week. The cold airmass advecting from the northwest across the
relatively warm lakes will allow for numerous snow showers and localized
areas of moderate to heavy snow. Specifically, the U.P. of Michigan and
Tug Hill Plateau of western New York could see several inches of
accumulation snow. Snowfall chances also extend to upslope portions of the
central Appalachians on Monday and Tuesday.

As a cold front pushes south and clears the Southeast by Monday, much
colder temperatures and high pressure will build in its wake. Low
temperatures are forecast to dip into the 20s and 30s from the Midwest to
the Tennessee Valley on Monday, prior to this cold sinking into the
Mid-South and Southeast on Tuesday. Vegetation in these regions are
susceptible to frost/freeze damage given the relatively mild late winter
temperatures, thus any unprotected sensitive plants could be damaged or
killed. Meanwhile, warm temperatures will remain locked in place over the
Pacific Northwest, where highs into the low 70s are forecast and
anticipated to spread into the northern High Plains by Monday.

One more day of shower and thunderstorm activity is expected today along
the Gulf Coast as a lingering frontal boundary focuses rainfall chances.
Heavy rain could lead to flooding concerns from southeast Texas to
southern Louisiana due to saturated soils from recent rainfall. A Slight
Risk (level 2 of 4) of Excessive Rainfall is in effect. A few isolated
severe thunderstorms could also impact the immediate Gulf Coast region as
well this St. Patrick’s Day.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Sat Mar 16 2024
Valid 12Z Sat Mar 16 2024 – 12Z Mon Mar 18 2024

…Heavy mountain snow impacts the Four Corners and Southern Rockies this
weekend…

…Severe thunderstorms and heavy rain possible across southern Texas and
along the Gulf Coast…

…Mild weather continues across the Pacific Northwest and East Coast…

The lingering closed upper low located over the Desert Southwest is
forecast to remain mostly stationary this weekend and produce the
continued threat of heavy mountain snow from the Four Corners region to
the Southern Rockies. In particular, the high terrain of central/southern
Utah as well as the San Juan and Sangre de Cristo Mountains of Colorado
and New Mexico can expect treacherous conditions due to heavy snow.
Additional snowfall accumulations over a foot are expected for parts of
the Southern Rockies through Monday, with Winter Storm Warnings and Winter
Weather Advisories remaining in effect.

Meanwhile, a stalling cold front extending from the Southeast to southern
Texas will lead to at least a few more days of storminess for the Lone
Star State and remaining Gulf Coast region. The greatest severe weather
threat exists today across south-central Texas and the Middle Texas Coast,
where the Storm Prediction Center has highlighted a Slight Risk (level 2
of 5) for severe thunderstorms. Large hail, damaging winds, and isolated
tornadoes are possible within the strongest storms. Intense rainfall rates
falling over saturated ground may also lead to flash flooding and standing
water in urban areas throughout similar portions of Texas and stretching
into far southwest Louisiana. By Sunday, shower and thunderstorm activity
is expected to stretch along most of the Gulf Coast, with isolated to
scattered chances for severe weather and flash flooding. Given recent
rainfall, parts of southwest Louisiana and southeast Texas have been
designated as having a Slight Risk (level 2 of 4) for Excessive Rainfall.

The other notable system to impact the CONUS through early next week is
forecast to clip the Great Lakes and northern New England, producing
mostly light rain and snow showers as well as gusty winds and cooler
temperatures. Locally heavy snow is possible downwind of the Great Lakes
on Sunday and Monday. Before the chilly and below average airmass
progresses into the eastern third of the Nation on Monday, mild afternoon
temperatures into the 60s and 70s can be expected this weekend in the
East. More importantly, the cold airmass on the way will contain a morning
frost/freeze threat on Monday throughout the Midwest and Ohio Valley as
lows dip into the 20s and 30s.

Upper riding anchored over the Northwest will continue the warm and dry
pattern throughout the Pacific Northwest and northern Great Basin,
expanding into the northern High Plains on Monday. Highs into the 60s and
70s are forecast, which could break a few daily high temperature records.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Fri Mar 15 2024
Valid 12Z Fri Mar 15 2024 – 12Z Sun Mar 17 2024

…Heavy mountain snow continues throughout the Four Corners region into
this weekend…

…Severe thunderstorm and excessive rainfall chances shift south into the
Southeast and Gulf Coast States…

…Mild weather continues across the Pacific Northwest and East Coast…

A meandering closed upper low spinning over the Desert Southwest will
continue to funnel moisture northward into the Four Corners region and
create additional chances for heavy mountain snow through the weekend.
Snow chances will diminish today across the central/southern High Plains
as upslope flow weakens, but mountainous terrain of the central and
southern Rockies can expect an additional 1 to 2 feet of snow through
Sunday. The higher elevations of southern Utah and Arizona can also expect
snowfall accumulations over a foot, which will create hazardous driving
conditions. Winter Storm Warnings and Winter Weather Advisories remain in
effect for these regions.

Farther east, waves of low pressure and an associated cold front are
forecast to slide south and east today while stretching from the
Mid-Atlantic to the Southern Plains. Heavy rain and scattered
thunderstorms will accompany this system, with the greatest chances for
severe weather and/or flash flooding located across parts of the Mid-South
and south-central Texas. For these areas, thunderstorms could be strong
enough to contain damaging wind gusts and isolated tornadoes. Meanwhile,
the primary risk across south-central Texas is expected to be associated
with large hail and scattered flash flooding. By this weekend, the
aforementioned frontal boundary is forecast to stall along the Gulf Coast
and southern Texas, resulting in additional chances for heavy rain that
could lead to scattered flooding concerns from south-central Texas to
southern Mississippi.

The other notable weather system to impact the Lower 48 will be a potent
low pressure system passing to the north of the Great Lakes on Saturday
and nearing Maine on Sunday. The greatest impacts are anticipated to be
associated with gusty winds across the Great Lakes and decreasing
temperatures throughout the Upper Midwest by Sunday. Additionally, periods
of lake effect snow could be locally heavy across the U.P. of Michigan
downwind of Lake Superior. Otherwise, strong southerly flow on the eastern
side of this system will keep much of the East Coast mild with high
temperatures mainly in the 60s and 70s. The other warm spots over the next
few days include the Pacific Northwest and Southeast, where a few daily
record highs are possible. Parts of western Washington and Oregon may see
highs into the mid-70s, while mid-to-upper 80s are found throughout the
Sunshine State.

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

…Heavy snow develops over central Colorado Wednesday night into Thursday
followed by rain/mountain snow across the Four Corners to the southern
High Plains Thursday into Friday…

…Strong to severe thunderstorms possible from the Midwest to the
southern Plains from this evening into Thursday…

…Strong to severe thunderstorms with a slight risk of excessive rainfall
expected Thursday evening into early Friday from the southern Plains to
the Mid-South...

An amplifying upper-level trough digging into the western U.S. is
gradually pushing the unsettled weather out of the Pacific Northwest into
the Intermountain region. The interaction of the upper trough with colder
air filtering southward is setting the stage for a long-duration snow
event from the central Rockies and down into the Four Corners over the
course of the next few days. The precipitation will first be focused over
the central Rockies from this evening into Thursday when wet snow is
forecast to be the heaviest across the Front Range of Colorado where a few
feet of new snow could fall. Lesser amounts are expected in adjacent
areas but one to two feet of wet snow is possible down into the High
Plains at locations such as Boulder and Denver, Colorado. Hazardous to
very difficult travel is expected as heavy snow and intense snow rates at
times (1-2 inches plus per hour) will lead to deteriorating travel
conditions beginning Wednesday and Wednesday night across the
central/southern Rockies and beginning across the Four Corners region
Thursday night.

A second phase of the winter storm will then impact the Four Corners
Region beginning Thursday night, as the upper trough closes off into a
slow-moving upper low. Waves of heavy snow will impact the terrain areas
north of the Mogollon Rim and northeast toward the San Juans and southern
Colorado Rockies. Snow probabilities for 8 inches are moderate to high
(greater than 50%). Localized totals above a foot are possible for the
higher terrain.

On the warm side of the system, low relative humidity and gusty winds will
continue to raise the danger of wildfires to locally extreme levels from
the Texas Panhandle to western Texas today. The dry environment in the
Plains states will initially limit the formation of showers and some
thunderstorms across the mid-Mississippi Valley into the Midwest.
However, as a low pressure system develops and tracks across the central
Plains towards the Midwest, influx of moisture from the Gulf of Mexico is
forecast to organize an area of enhanced rainfall across Arkansas and
neighboring areas Thursday evening into early Friday when severe weather
is possible. The heavy rain and severe weather threat will then shift
northeast toward Tennessee by Friday morning as the trailing cold front
associated with the low pressure system approaches from the west. The low
pressure system itself will bring widespread moderate to locally heavy
rain with a slight threat of severe weather across the Midwest tonight,
followed by the southern half of the Great Lakes on Thursday, and into New
England Friday morning. The rain may mix with wet snow over the upper
Midwest tonight and over interior New England Friday morning.

As the winter storm develops over the western U.S., much of the eastern
U.S. will enter an extended period of very warm and pleasant weather.
High temperatures in the 60s and 70s from the Ohio Valley to the
Mid-Atlantic states will be 20-25 degrees above normal for this time of
year.

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

…One more day of unsettled weather across the Pacific Northwest and
northern California before the precipitation gradually tapers off on
Wednesday…

…Mountain snows spreading into the northern and central Rockies on
Wednesday before heavy snow develops over central Colorado Wednesday
night…

…Fire danger across the southern High Plains will be followed by chance
of severe thunderstorms across the north-central Plains later on Wednesday
as rain may change over to wet snow in the nearby High Plains…

…Anomalously warm temperatures to expand eastward from the Upper Midwest
into the Ohio Valley, Mid-Atlantic and Northeast through Wednesday…

A gradual shift in the large-scale upper-level pattern across the U.S.
will bring unsettled weather that has been impacting the Pacific Northwest
in recent days progressively eastward into the central U.S. by Wednesday
night. The final in a series of Pacific fronts and low pressure systems
will push onshore into the West Coast today, bringing additional mountain
snow and lower-elevation rain with one to possibly two feet of new snow
along the Cascades. As the main upper trough presses eastward through the
western U.S. the next couple of days, areas along the West Coast will have
a chance to gradually dry out on Wednesday. Meanwhile, the main batch of
moisture will penetrate farther inland in the form of mountain snow
pushing into the northern to central Rockies on Wednesday. The upper
trough will also help develop a low pressure system over the central High
Plains on Wednesday. The interaction of the upper trough with the
intensifying low pressure system will begin to organize and focus an area
of moderate to heavy snow over central Colorado by early on Thursday. By
Thursday morning, snow could be falling in earnest over the mountainous
terrain into the Front Range and nearby High Plains of central Colorado.

On the warm side of the low pressure system, low relative humidity and
gusty winds will continue to raise the danger of wildfires across central
to southern High Plains today, followed by a more southward focus from the
Texas Panhandle to western Texas on Wednesday. The dry environment in the
Plains states will initially limit the formation of showers and some
thunderstorms across the mid-Mississippi Valley into the Midwest today
into early on Wednesday. However, as the low intensifies, influx of
moisture from the Gulf of Mexico is forecast to organize an area of
enhanced rainfall over the vicinity of Nebraska Wednesday night as the
storm center passes just to the southeast. Some of the enhanced rainfall
could be accompanied with severe weather. In addition, there is a
possibility that the western portion of the enhanced rainfall would change
over to wet snow early on Thursday if additional cold air wraps around the
storm center.

Across the eastern U.S., the departure of a strong surface low near Nova
Scotia into the western Atlantic will allow the gusty winds to moderate
further across the northern Mid-Atlantic and Northeast today. Breezy
conditions are likely to remain for northern New England into Tuesday
night, but overall improvement is expected. High pressure over the
southern U.S. will slide eastward over the next couple of days, allowing
winds to return from the south, bringing warmer temperatures northward.
The greatest departures from normal highs will remain over the Upper
Midwest and Great Lakes region on Tuesday which may cause a few record
daily maximum temperatures to be broken, but the magnitude of the
anomalous warmth is likely to be lower on today compared to Monday. High
temperatures in the 60s to lower 70s will expand eastward through
Wednesday across the Ohio Valley and portions of the northern Mid-Atlantic
into the Northeast, roughly 15 to 25 degrees above mid-March averages.
With the warmer weather will come the threat for thunderstorms across
portions of the central U.S. Some severe thunderstorms will be possible
ahead of a dryline from eastern Oklahoma/Kansas into western Missouri on
Tuesday with a broader risk across some of these same areas on Wednesday.
Again, the prevailing dry environment will initially limit the intensity
of the storms.

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

…Heavy wet snow will continue into the morning hours on Monday across
the higher elevations of the northern New England and portions of the
lower Great Lakes…

…Unsettled weather is expected to persist across the Pacific Northwest
and into the northern Rockies with multiple rounds of lower-elevation rain
and higher elevation snow…

…Fire danger to increase across the central and southern High Plains
from very dry conditions, gusty winds, and warm temperatures…

A deep low pressure system centered over Downeast Maine early this morning
will be slow to move away into the Canadian Maritimes. The ongoing heavy
wet snow associated with this system is expected to linger across the
higher terrain from the Adirondacks of New York, up across the Green and
White Mountains of Vermont and New Hampshire respectively. Meanwhile, the
cold air pouring southeast over the lower Great Lakes will sustain heavy
lake-effect snow shower activity with squalls locally across upstate New
York into the morning of today before they gradually taper off during the
afternoon. The snow will likely taper off to snow showers and flurries by
tonight across northern Maine. Nevertheless, the strong and gusty winds
are expected to persist into Tuesday as the large circulation of the low
pressure system will take time to depart.

In the wake of the low pressure system, a large dome of high pressure will
build across the South and into the Southeast while taking its time to
slide off into the Atlantic. Temperatures over the next couple of days
will be well above normal especially across the central and northern
Plains and the Midwest before gradually advancing into the Great Lakes and
Ohio Valley. The return of dry weather coupled with increasingly gusty
winds and low relative humidity will promote an increased risk of
wildfires. In fact, the Storm Prediction Center has highlighted large
areas of the central and southern High Plains in an elevated to critical
fire danger area. This will include the panhandles of Texas and Oklahoma
where devastating fires occurred a couple weeks ago.

Meanwhile across the Pacific Northwest, multiple low pressure systems
arriving from the Pacific will bring frequent rounds of precipitation
onshore and then farther inland into the northern Rockies through the next
couple of days. Moderate to locally heavy rain is expected for the coastal
ranges with heavy snow over the higher elevations of the Cascades,
northern Sierra Nevada, and the Sawtooth, Bitterroot, and Teton ranges of
the northern Rockies. The Cascades will likely receive the heaviest
snowfall totals where as much as 1 to 2 feet of new snow can be expected.

Temperatures are expected to begin rebounding rather quickly for much of
the East and the South by later Tuesday as milder air from the Plains and
Midwest advances east together with warm air beginning to return north
from the Gulf of Mexico. High temperatures across portions of eastern
South Dakota, Minnesota, Iowa, and Wisconsin are forecast to be as much as
30 to 40 degrees above normal on today and Tuesday with temperatures
approaching or locally exceeding 70 degrees. Some cities will likely be
warm enough to see their daily high temperature records either tied or
broken today.

Meanwhile, a cooling trend is expected across the western U.S. as colder
air associated with an upper trough pushes inland to bring moderate to
locally heavy mountain snow into the central Rockies by early Wednesday
while the West Coast begins to dry out. Farther east, a low pressure
system is forecast to develop over the central to southern High Plains
Tuesday night. The dry environment in the vicinity will initially limit
the formation of showers and some thunderstorms across the mid-Mississippi
Valley into the Midwest early on Wednesday. Some light snow could brush
the northern Plains near Canadian border early Wednesday ahead of a
clipper system.

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

…Heavy rain and some severe weather expected to move across the
Southeast today followed by heavy rain and strong winds across the
Mid-Atlantic and southern New England tonight into Sunday morning…

…Wet snow and strong winds across northern New England from tonight
through much of Sunday followed by lake-effect snows across the lower
Great Lakes into Monday morning…

…Frequent rounds of lower-elevation rain and mountain snow expected to
reach the Pacific Northwest through the next couple of days…

A complex interaction among a cold air mass dipping into the mid-section
of the country, an amplifying upper-level trough, moist air from the Gulf
of Mexico ingesting into the South, and a subtropical jet stream will
bring widespread increment weather through the eastern U.S. into Sunday.
The heaviest rainfall is expected to be found across the Southeast where
some of the thunderstorms could become severe. The Weather Prediction
Center has a Slight Risk of excessive rainfall forecast for the eastern
Carolinas for today. The low pressure center that forms and intensifies
along the southern front is forecast to track up the East Coast and reach
southern New England by early on Sunday. Areas from central Appalachians
into southern New England are expected to see a period of moderate to
occasionally heavy rain later today into early Sunday as the low pressure
center passes just to the southeast. Farther inland, colder air wrapping
around the intensifying storm will support wet snow across northern New
England during the same time period. This will be followed by lake-effect
snows across the lower Great Lakes into Monday morning when colder air
pours in behind the big low. Strong and gusty winds will expand and then
engulf the entire northeastern U.S. as the big low intensifies further and
begins to exit into the Canadian Maritimes by Monday morning.

In the wake of the storminess in the East, high pressure will take over
the entire central and southern U.S. with dry conditions persisting into
the new work week. The dry weather will extend into much of the western
U.S. as well. However, moisture associated with the next Pacific system
is forecast to reach the Pacific Northwest in a hurry today in the form of
lower-elevation rain and mountain snow for rather high elevations. More
systems arriving from the Pacific will result in frequent rounds of
precipitation persisting across the western portions of Washington,
Oregon, and down into northern California. The Cascades and higher
terrain of northern California will likely receive a couple more feet of
new snow through Monday.

Temperatures will generally be cooler than normal across the South but
above normal across the North. The East will be milder than normal today
ahead of the intensifying low pressure system before colder air surges
into the region on Sunday. Temperatures across the West will average near
normal.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
300 AM EST Fri Mar 08 2024

Valid 12Z Fri Mar 08 2024 – 12Z Sun Mar 10 2024

…Snow gradually tapering off over the central High Plains as well as
central/southern Rockies…

…Threat of flash flooding and severe weather expected to sweep across
the Deep South to the Southeast through the next couple of days…

…An intensifying low pressure system will bring locally heavy rain and
strong winds from the Ohio Valley to New England late Saturday into
Sunday…

…Wet snow expected across the Great Lakes to northern New England late
Saturday to Sunday as next round of rain and mountain snow reaches the
Pacific Northwest…

Upper-level moisture arriving from the eastern Pacific in association with
a subtropical jet stream will interact with a cold air mass dipping into
the mid-section of the country through the next couple of days. This
interaction will result in active to locally severe weather to move from
west to east across many areas of the eastern half of the country through
Sunday morning. In addition, lower-level moisture from the Gulf of Mexico
will be ingested into the system. These complex interactions will result
in an axis of heavy rain and possibly severe weather to blossom later
today across the lower Mississippi Valley, spreading through the Deep
South Friday night, and then through the Southeast on Saturday.
Meanwhile, a low-level disturbance that has been sustaining locally heavy
snow over the central High Plains is forecast to weaken and allow the snow
there, as well as the snow over the central to southern Rockies, to
gradually taper off today into this evening. By Saturday, a low pressure
center is forecast to consolidate over the Ohio Valley when the system
intensifies more rapidly and tracks northeastward into the lower Great
Lakes Saturday night. Locally heavy rain and increasingly strong and
gusty winds are expected to develop from the Ohio Valley to New England
late Saturday into Sunday. Colder air wrapping around the low pressure
center is expected to change the rain to wet snow from across the Great
Lakes to portions of northern New England especially for the higher
elevations.

Much of the Great Plains will dry out on Saturday behind the low pressure
system as a high pressure system takes over. The dry weather will extend
into much of the western U.S. However, moisture associated with the next
Pacific system is scheduled to reach the Olympic Peninsula later today
with rain for the lower elevations and snow for rather high elevations.
The rain and mountain snow will expand southward across Oregon and into
northern California on Saturday into Saturday night. The Cascades will
see snow picking up intensity on Saturday as the next batch of moisture
getting ready to reach the coastline of the Pacific Northwest by early on
Sunday.