Atmospheric Rivers

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Sun Oct 27 2024
Valid 12Z Sun Oct 27 2024 – 12Z Tue Oct 29 2024

…Scattered light rain will develop over the Carolinas…

…Rain and higher elevation snow over parts of the Northeast Sunday
night…

…Rain moves into the Northwest and light snow over the higher elevations
of the Western States…

A front lingering along the Gulf Coast States will slowly dissipate by
Monday. Upper-level impulses over the Ohio and Lower Mississippi Valleys
will produce scattered rain over parts of the Lower Mississippi Valley
through late Sunday morning. In addition, upper-level dynamics will
develop light rain over parts of the Carolinas early Sunday through early
Monday morning. Furthermore, onshore flow off the Atlantic will create
scattered rain over parts of Florida from Monday afternoon through Tuesday.

Meanwhile, a front over the Pacific Northwest will move inland to the
Upper Mississippi Valley to the Central Plains and then to the Southwest
by Tuesday. The storm will produce rain over parts of the Pacific
Northwest and Northern California through Sunday afternoon. Onshore flow
off the Pacific will produce rain over the Pacific Northwest and Northern
California through Monday night. As the front passes over the Northwest
into the Great Basin, scattered light snow will develop over the highest
elevations of the Cascades, the Sierra Nevada Mountains, the Northern
Intermountain Region, and the Great Basin through Tuesday.

As the leading edge of the boundary moves into the Upper Midwest, rain
with embedded thunderstorms will develop over parts of the Great Lakes
from Monday evening into Tuesday. Furthermore, ahead of the front,
temperatures will be 10 to 25 degrees above average over the Plains.

Elsewhere, a front will move southward out of Central Canada on Sunday,
advancing into the Northeast by Sunday evening and then out over the
Atlantic. This front will produce scattered rain and snow over the higher
elevations of the Northeast through early Monday morning.

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

…Showers and thunderstorms over parts of the Middle Mississippi/ Ohio
Valleys…

…Rain over parts of the Northeast…

…Rain moves into the Pacific Northwest…

A wave of low pressure over the Middle Mississippi Valley will move
northeastward off the Northeast Coast by Saturday evening. The system will
produce showers and thunderstorms over parts of the Middle
Mississippi/Ohio Valleys through Friday evening. The system will also
create rain over parts of the Great Lakes through Saturday afternoon.
Overnight Friday, scattered rain will develop over parts of the Northeast
through early Sunday morning. Moreover, scattered rain will develop along
the front over the Southern Mid-Atlantic from Saturday evening into
Sunday. Rain will also grow over parts of the Lower Mississippi Valley
from early Saturday into Sunday.

Meanwhile, a front will move onshore over the Pacific Northwest Friday
night and inland through Sunday morning. The storm will produce rain over
parts of the Pacific Northwest late Friday night. The rain will continue
to inch farther inland on Saturday, moving into Northern California late
Saturday night and continuing into Sunday.

Elsewhere, onshore flow off the Atlantic will trigger scattered rain over
parts of Florida from Saturday afternoon into Sunday.

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

…Pleasant weather continues across most of the country through the end
of the week…

…Well above-average temperatures continue over the Central and Southern
U.S…

A quiet and relatively uneventful fall weather pattern will continue to be
in place across the continental U.S. through the end of the week, with
high pressure keeping mainly sunny skies in place across the Central and
Eastern U.S. and the warm conditions continuing across the Plains and
southern tier states. A cold front approaching the East Coast will herald
the arrival of more autumnal temperatures for Thursday with highs falling
10 to 20 degrees for many areas from the Mid-Atlantic to the Northeast
compared to Wednesday. Even warmer conditions are likely for the central
and southern Plains to close out the work week, with highs running up to
20 degrees above normal for late October, with the potential for
additional record highs.

In terms of precipitation prospects, scattered showers and thunderstorms
are likely for the Midwest states ahead of the next cold front dropping
south across the Northern Plains on Thursday and into Thursday night. A
more concentrated corridor of heavier rainfall is expected from eastern
Iowa to northern Illinois on Thursday, with the potential for a few strong
thunderstorms in the warm sector of the surface low. There may also be a
few showers in easterly flow across the Florida Peninsula. Out West, some
showers and high elevation snow are expected from eastern Idaho to Wyoming
and southern Montana with a shortwave upper trough moving through the
region. Looking ahead to Friday, onshore flow ahead of a Pacific cold
front will lead to light to moderate rain developing across western Oregon
and Washington, but not considered an atmospheric river event.

The combination of very warm conditions, dry grounds, and increased winds
across the Central Plains will raise the potential for wildfires, based on
the SPC fire weather outlook on Thursday. There may also be some fire
weather concerns across portions of the Mid-Atlantic and the Northeast on
Thursday in the wake of a dry cold front, with dry conditions and gusty
winds developing.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Wed Oct 23 2024
Valid 12Z Wed Oct 23 2024 – 12Z Fri Oct 25 2024

…Very pleasant weather continues across most of the country through the
end of the week…

…Well above-average temperatures continue over the Central and Eastern
U.S…

A quiet and relatively uneventful fall weather pattern will be in place
across the continental U.S. through early Friday, with high pressure
keeping mainly sunny skies in place across the Central and Eastern U.S.
and the very pleasant conditions continuing. Temperatures will once again
be quite mild and feel more like September across much of the East Coast
region on Wednesday ahead of a cold front, which will herald the arrival
of more autumnal temperatures for Thursday with highs falling 10 to 20
degrees for many areas from the Mid-Atlantic to the Northeast. Even
warmer conditions are likely for the central and southern Plains to close
out the work week, with highs running up to 20 degrees above normal for
late October, with the potential for a few record highs.

In terms of precipitation prospects, some light showers are possible
across portions of the Great Lakes region and into New England ahead of
the cold front where forcing for ascent will be greatest, and remaining
dry farther to the south given a paucity of moisture and lack of dynamics.
A second area of scattered showers and thunderstorms is likely for the
Midwest states ahead of the next cold front dropping south across the
Northern Plains on Thursday and into Thursday night. There may also be a
few showers in easterly flow across the Florida Peninsula. Out West, some
showers and high elevation snow are expected from eastern Oregon to the
Northern Rockies with a shortwave upper trough moving through the region.

The combination of very warm conditions, dry grounds, and increased winds
across the Central Plains will raise the potential for wildfires, based on
the SPC fire weather outlook on Thursday. The same holds true for
portions of southern New England on Wednesday.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Mon Oct 21 2024
Valid 12Z Mon Oct 21 2024 – 12Z Wed Oct 23 2024

…Lingering scattered thunderstorm activity for the Central/Southern
Plains today…

…Cool and rainy across the Northwest today…

…Well above average temperatures in the northern tier spreads south…

A previously quasi-stationary front draped along the Central/Southern High
Plains will kick out into the Great Plains today beneath a weakening
upper-level low. Scattered showers and thunderstorms will occur over
portions of eastern Nebraska and Kansas as a result with a Marginal Risk
of Severe Thunderstorms present. A somewhat slow moving upper trough over
the eastern Pacific will produce cool temperatures and light rain showers
for much of the Northwest today.

An upper ridge and approaching northern stream trough will generate well
above average temperatures across much of the northern tier states today.
Temperatures in the 70s and 80s will represent 20-30 degree positive
anomalies for portions of the Upper Midwest. High temperature records
along the Northeast Coast may be tied or broken today.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Mon Oct 21 2024
Valid 12Z Mon Oct 21 2024 – 12Z Wed Oct 23 2024

…Lingering scattered thunderstorm activity for the Central/Southern
Plains today…

…Cool and rainy across the Northwest today…

…Well above average temperatures in the northern tier spreads south…

A previously quasi-stationary front draped along the Central/Southern High
Plains will kick out into the Great Plains today beneath a weakening
upper-level low. Scattered showers and thunderstorms will occur over
portions of eastern Nebraska and Kansas as a result with a Marginal Risk
of Severe Thunderstorms present. A somewhat slow moving upper trough over
the eastern Pacific will produce cool temperatures and light rain showers
for much of the Northwest today.

An upper ridge and approaching northern stream trough will generate well
above average temperatures across much of the northern tier states today.
Temperatures in the 70s and 80s will represent 20-30 degree positive
anomalies for portions of the Upper Midwest. High temperature records
along the Northeast Coast may be tied or broken today.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Sun Oct 20 2024
Valid 12Z Sun Oct 20 2024 – 12Z Tue Oct 22 2024

…Heavy Rain and light to moderate Snow across portions of the Central
Rockies, and Southern High Plains today before diminishing tonight…

…Rainfall for the Pacific Northwest through Monday…

…Expansive area of above average temperatures settle over the northern
tier…

An anomalous closed upper-level low pressure system will continue to
produce heavy rainfall and scattered thunderstorms across portions of the
Southern High Plains through this morning before quickly tapering off this
afternoon and evening. A Slight Risk of Excessive Rainfall leading to
Flash Flooding is in effect for parts of far southeastern Colorado, the
Texas/Oklahoma panhandles and northeastern New Mexico where 1 inch/hr rain
rates could cause runoff concerns, particularly over recent burn scars.
Heavy snow is also a concern over parts of the Central Rockies,
specifically the San Juans above 10,000 feet where over 8 inches of snow
are possible. Snow tapers off tonight as the upper low moves away into the
Great Plains.

A broad positively tilted upper trough will continue generating a
prolonged weak atmospheric river event over the Northwest over the next
couple of days. Some additional 1-2 inches of rainfall are possible for
parts of the Pacific Northwest today followed by portions of the Northern
Rockies on Monday. Any snow that falls will be confined to the highest
elevations of the Cascades.

An upper ridge will promote warm southerly flow into the Plains and
eventually East over the next several days. High temperatures in the 70s
and 80s today and Monday will represent 20-30 degree positive anomalies
for this time of year over parts of the Upper Midwest. Overnight
temperatures will be warm enough to rival low records as well. Troughing
over southern Canada and the cut-off low propagating across the Plains
will eventually push the warm air into the eastern half of the country
this week.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Fri Oct 18 2024
Valid 12Z Fri Oct 18 2024 – 12Z Sun Oct 20 2024

…Heavy snow expected for the central and southern Rockies through
Saturday…

…Heavy rain expected for the western High Plains on Saturday ahead of an
upper low over the Four Corners region…

…Sunny and pleasant conditions for much of the Eastern U.S. through the
upcoming weekend…

A weather pattern change is in progress across the Western U.S. as an
amplified upper trough supports the passage of a strong cold front across
the Intermountain West. This will result in widespread mountain snow
across the higher elevations of the Rockies on Friday, and persisting into
Saturday across the mountainous terrain of the Four Corners region as an
upper level low develops. The potential exists for 10-20 inches of snow
across portions of Utah and Colorado, mainly above 9000 feet elevation.
It will also be turning considerably colder compared to the recent warm
weather that most of the Western U.S. has experienced so far this month.
Highs will only be in the 40s and 50s for most valley locations to close
out the work week and going into Saturday, and below freezing at night.

With the upper level low developing over Arizona, there will be a plume of
increased moisture advection across eastern New Mexico and portions of
adjacent states that will likely result in enhanced rainfall going into
Saturday, where a Slight Risk of excessive rainfall is currently depicted
in WPC’s outlook. The potential exists for 2-4 inches of rainfall here,
and this could result in some instances of flooding. Some strong to
severe thunderstorms will also be possible. Another area of enhanced
rainfall will be across western Washington, where an atmospheric river
event will likely affect Vancouver Island and the Olympic Peninsula,
producing a few inches of rainfall across the windward terrain.

Elsewhere across the continental U.S., a sprawling surface high will be
anchored in place across the Eastern U.S. and will govern the overall
weather pattern through the upcoming weekend. The result will be sunny
skies across a wide expanse of this region, and pleasantly mild conditions
during the day and cool at night. There will be a moderating trend with
temperatures compared to the recent cold spell earlier this week, and
highs are expected to be above normal for many areas with readings well
into the 70s from the Midwest to the Northeast states. The downside is
the developing short term drought conditions for much of this region, with
no rainfall expected through early next week.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Fri Oct 18 2024
Valid 12Z Fri Oct 18 2024 – 12Z Sun Oct 20 2024

…Heavy snow expected for the central and southern Rockies through
Saturday…

…Heavy rain expected for the western High Plains on Saturday ahead of an
upper low over the Four Corners region…

…Sunny and pleasant conditions for much of the Eastern U.S. through the
upcoming weekend…

A weather pattern change is in progress across the Western U.S. as an
amplified upper trough supports the passage of a strong cold front across
the Intermountain West. This will result in widespread mountain snow
across the higher elevations of the Rockies on Friday, and persisting into
Saturday across the mountainous terrain of the Four Corners region as an
upper level low develops. The potential exists for 10-20 inches of snow
across portions of Utah and Colorado, mainly above 9000 feet elevation.
It will also be turning considerably colder compared to the recent warm
weather that most of the Western U.S. has experienced so far this month.
Highs will only be in the 40s and 50s for most valley locations to close
out the work week and going into Saturday, and below freezing at night.

With the upper level low developing over Arizona, there will be a plume of
increased moisture advection across eastern New Mexico and portions of
adjacent states that will likely result in enhanced rainfall going into
Saturday, where a Slight Risk of excessive rainfall is currently depicted
in WPC’s outlook. The potential exists for 2-4 inches of rainfall here,
and this could result in some instances of flooding. Some strong to
severe thunderstorms will also be possible. Another area of enhanced
rainfall will be across western Washington, where an atmospheric river
event will likely affect Vancouver Island and the Olympic Peninsula,
producing a few inches of rainfall across the windward terrain.

Elsewhere across the continental U.S., a sprawling surface high will be
anchored in place across the Eastern U.S. and will govern the overall
weather pattern through the upcoming weekend. The result will be sunny
skies across a wide expanse of this region, and pleasantly mild conditions
during the day and cool at night. There will be a moderating trend with
temperatures compared to the recent cold spell earlier this week, and
highs are expected to be above normal for many areas with readings well
into the 70s from the Midwest to the Northeast states. The downside is
the developing short term drought conditions for much of this region, with
no rainfall expected through early next week.