Atmospheric Rivers

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Sun Oct 06 2024
Valid 12Z Sun Oct 06 2024 – 12Z Tue Oct 08 2024

…Tropical Storm Milton continues to intensify over the southwest Gulf of
Mexico and is expected to move northeastward towards the Florida Gulf
Coast…

…Very heavy rainfall well ahead of Tropical Storm Milton will arrive
across the Florida Peninsula and Keys bringing the threat of flash
flooding…

…Showers and thunderstorms expected for portions of the interior
Northeast Sunday with the threat for some large hail and damaging winds…

…Record-breaking heat will continue across California and the Southwest
through the remainder of the weekend and into early next week…

Tropical Storm Milton continues to intensify in the southwestern Gulf of
Mexico and is currently forecast by the National Hurricane Center (NHC) to
move northeastward towards the Gulf Coast of Florida, with a possible
landfall on Wednesday. However, potentially significant flooding impacts
are expected well ahead of the storm as anomalously moist tropical air and
instability increase south of a wavy frontal boundary draped across the
Florida Peninsula. There is now a Moderate Risk of Excessive Rainfall
(level 3/4) Sunday over South Florida for a more concentrated corridor of
thunderstorms producing intense downpours with totals that could exceed
5″. This will bring a more significant risk of scattered to numerous
instances of flash flooding in urban areas. A Slight Risk (level 2/4)
extends north along the Atlantic Coast and also west along the Gulf Coast
through the central Peninsula for additional scattered instances of flash
flooding. Another Slight Risk on Monday covers the Atlantic Coast of the
central Peninsula as well as the southwestern Gulf Coast and South Florida
as the threat for thunderstorms with very heavy rainfall and flash
flooding continues. Follow the latest forecast from the NHC for updated
information on the expected track and potential impacts mid-week.

An upper-level wave/surface frontal system will pass through areas of the
interior Northeast including the Appalachians, Lower Great Lakes, and the
Upper Ohio Valley Sunday bringing scattered showers and thunderstorms.
Sufficient instability ahead of the front as well as strong flow at the
low and mid-levels may lead to some more robust, severe thunderstorms. The
Storm Prediction Center (SPC) has highlighted western New York and
Pennsylvania as well as eastern Ohio and the northern Panhandle of West
Virginia with a Slight Risk (level 2/5) of severe weather mainly for the
threat of large hail and damaging winds. The SPC has also noted that gusty
winds and dry conditions behind a trailing cold front extending to the
southwest through the Midwest and into the central Plains will lead to an
Elevated Risk of fire weather. As the system continues eastward, showers
and thunderstorms will spread into the northern Mid-Atlantic late
Sunday/early Monday and into New England during the day Monday. Most of
the rest of the country will be without precipitation chances the next
couple of days expect the Pacific Northwest where rain chances will pick
up by later Monday ahead of a Pacific system.

A record-breaking late-season heat wave continues this weekend and into
early next week across central and southern California and the Desert
Southwest as a ridge of high pressure aloft persists over the region.
Forecast highs continue to soar into the upper 90s to low 100s outside of
the immediate coastal areas of central and southern California, with high
temperatures reaching as high as the low 110s for the interior portions of
the Desert Southwest. Numerous daily record-tying or record-breaking high
temperatures are expected to occur across the region going through Monday.
Heat-related advisories and warnings are in place as this persistent level
of major to extreme heat remains a danger to anyone without adequate
air-conditioning or hydration, and for those spending greater time
outdoors. While not quite as hot, highs will trend above average again for
most of the rest of the Intermountain West as well, with highs in the 70s
and low 80s for the northern Great Basin/Rockies and into the mid-80s for
the central Great Basin. These very warm temperatures will also spread
east out into the northern/central Plains early next week. In fact, by
Monday and Tuesday, some areas of the northern Plains are expected to see
high temperatures upwards of 20 degrees above average, reaching as high as
the upper 70s and low 80s. Much of the Ohio/Tennessee Valleys and
Mid-South/Lower Mississippi Valley will see unseasonably warm temperatures
well into the 80s on Sunday. A cold front passage will bring much cooler,
more seasonable temperatures to the Great Lakes/Ohio Valley Monday as
highs only top out in the 60s, with 70s into the Tennessee Valley and
Mid-South. Further south, hot temperatures will also continue for portions
of the southern Plains and Texas, with daily highs remaining in the upper
80s to mid-90s.

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

…Record-breaking heat remains across California and the Southwest
through this weekend, while briefly overspreading portions of the Plains
and Midwest on Saturday…

…Strong winds and dangerous fire weather conditions are forecast from
the northern/central Rockies into the Plains on Saturday…

…Locally heavy rainfall will be possible across the immediate Gulf Coast
through Saturday, with more of a focus toward the Florida Peninsula by
late Sunday…

A record-breaking late-season heat wave continues over portions of
central/southern California and the Desert Southwest this weekend as
upper-level ridging persists over the region. Forecast highs will once
again soar into the upper 90s to low 100s outside of immediate coastal
areas in central/southern California and into the 100s to low 110s into
the Desert Southwest. Numerous daily record-tying/breaking highs will
likely be reached again following days of new record daily temperatures.
Heat-related advisories and warnings are in place as this persistent level
of major to extreme heat remains a danger to anyone without adequate
air-conditioning/hydration and those spending greater time outdoors. After
a brief period of more seasonable temperatures to the north following a
cold frontal passage, highs will trend above average again for most of the
rest of the Interior West by Sunday, with 70s into the northern Great
Basin/Rockies and 80s for the central Great Basin. Further to the east
over the central U.S., a brief period of upper-level ridging and strong
southerly flow ahead of an approaching system will bring some hotter high
temperatures to portions of the Midwest and Central Plains on Saturday.
Forecast highs into the low to mid-90s are upwards of 20 degrees above
average, and some record-tying/breaking temperatures possible here as
well. An approaching cold front will bring cooler, more seasonable air on
Sunday with highs back down into the 70s. The Southern Plains will remain
hot and above average south of the front through the weekend with upper
80s and low 90s forecast.

As noted, an upper-level wave will move quickly along the northern-tier of
the country this weekend with an accompanying surface frontal system. Lee
cyclogenesis east of the Rockies has led to a rapidly deepening area of
low pressure just north of the U.S./Canadian border, with a tightening
pressure gradient leading to widespread very strong, gusty winds across
the northern/central Rockies and into the northern/central Plains.
Wind-related advisories and warnings are in place for gusts upwards of
60-70 mph through Saturday. In addition, very dry conditions combined with
the gusty winds with cold frontal passage will also bring a significant
risk of wildfires. The Storm Prediction Center has highlighted areas from
northern Colorado/southern Wyoming into central Nebraska and southern
South Dakota with a Critical Risk of fire weather (level 2/3). Widespread
Red Flag Warnings and Fire Weather Watches cover much of the rest of the
region due to wildfire risk. Greater moisture further east will lead to
some showers and storms ahead of the frontal system over the Upper Great
Lakes by Saturday afternoon. Some moderate rainfall will be possible, and
strong dynamic forcing with the system could lead to some more potent
thunderstorms. A Slight Risk of severe weather (level 2/5) has been
introduced from the Storm Prediction Center in northeastern Wisconsin
mainly for the threat of some large hail. The system will continue into
the Northeast Sunday afternoon/evening with more showers and thunderstorms
expected.

An area of low pressure over the southwestern Gulf of Mexico and
increasing Gulf moisture will lead to periods of thunderstorms producing
locally heavy rainfall along the immediate Gulf Coast and eastward along a
surface trough/weak frontal boundary across the Florida Peninsula this
weekend. While storms may be generally ill-focused for any potential
flooding threat, a couple areas will see a low but non-zero risk. More
concentrated storms along a coastal trough nearby the far south Texas Gulf
Coast could lead to some isolated flash flooding on Saturday. Another
focus will be along and ahead of the weak frontal boundary through the
central Florida Peninsula on Sunday, with some isolated flash flooding
possible along the Florida Gulf Coast and South Florida. The National
Hurricane Center (NHC) continues to monitor this area of low pressure for
potential tropical development, though if something were to develop this
remains more likely after the current forecast period into next week.

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

…Record-breaking heat remains across California and the Southwest
through this weekend, while also building into the central United States
on Saturday…

…Strong winds and dangerous fire weather concerns forecast throughout
the northern Great Basin, northern Rockies, and into the northern/central
Plains…

…Locally heavy rain possible across the immediate Gulf Coast as
unsettled weather develops in the Gulf of Mexico…

A Fall heatwave will continue into the weekend over portions of the Desert
Southwest and central/southern California as a persistent trend of
upper-ridging over the region remains in place. Numerous
record-tying/breaking highs are forecast as temperatures soar once again
into the upper 90s to 100s. Heat-related advisories/warnings are in place
as the heat remains at levels dangerous to anyone without adequate cooling
or hydration. While not quite as hot, temperatures will still be
well-above average Friday elsewhere across the Interior West, with highs
well into the 80s for many locations across the northern/central Rockies
and Great Basin. A cold front will bring cooler, more Fall-like
temperatures to the northern Great Basin/Rockies on Saturday. Higher
heights will also expand eastward over the central United States on
Saturday helping to spread much above average temperatures into portions
of the central/southern Plains and Upper Midwest. Forecast highs in the
80s to low 90s in the Upper Midwest and as high as the mid-90s in the
central Plains are upwards of 20 degrees above average, with
record-tying/breaking highs possible here as well.

A fast-moving upper-level wave/accompanying surface frontal system will
pass along the northern tier of the West and into the central U.S. over
the next couple of days. Some moderate to locally heavy rainfall will be
possible over the Pacific Northwest on Friday, with some lighter showers
into the northern Rockies. Additional showers/storms will accompany the
system as it reaches the Upper Great Lakes later Saturday and into the
early morning hours Sunday. However, the bigger story will be widespread
gusty winds and high fire danger with the fast moving system as it passes
through the northern Great Basin/Rockies Friday and into the northern High
Plains Saturday. Wind-related watches and warnings have been issued as
gusts higher than 60 mph can be expected, leading to risk of blowing
debris, potential property damage, and isolated power outages, as well as
difficult travel conditions especially for high-profile vehicles. In
addition, the gusty winds and very dry conditions ahead of the approaching
cold front with the system will bring an increased threat for wildfires.
The Storm Prediction Center has highlighted a Critical Risk (level 2/3) of
Fire Weather over portions of the northern Great Basin and central/eastern
Wyoming Friday, and the central Rockies into the central Plains on
Saturday. Much of the rest of the region is under Red Flag Warnings and
Fire Weather Watches.

Enhanced tropical moisture along the Gulf Coast will lead to periods of
moderate to locally heavy showers for the next few days. The lack of a
focusing system/boundary and scattered nature of the storms currently
suggests a low risk for flash flooding, but an isolated instance or two of
flash flooding cannot be ruled out. Elsewhere, some light to moderate
showers can be expected with a cold frontal passage through the Northeast
late Friday/early Saturday. High temperatures will generally be at to a
bit above average for the eastern U.S., with widespread 70s to the north
and 80s in the South.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Thu Oct 03 2024
Valid 12Z Thu Oct 03 2024 – 12Z Sat Oct 05 2024

…Showers and thunderstorms return to the Gulf Coast from Thursday
evening into Saturday…

…Rain develops over the Pacific Northwest and scattered showers over
parts of the Midwest, Central/Southern Appalachians, and Northeast…

…There are Excessive Heat Warnings and Heat Advisories over parts of
Southern California and the Southwest…

On Thursday, tropical moisture will start to build over the
Central/Eastern Gulf Coast and Florida. Upper-level energy over the
Western Gulf Coast and Northern Gulf of Mexico will move into parts of the
Southeast and Central Gulf Coast, producing showers and thunderstorms over
parts of the Gulf Coast from Thursday evening into Saturday. In addition,
showers and thunderstorms will develop over parts of Florida through
Saturday. Furthermore, the moisture will also build over the
Central/Southern Appalachians, as upper-level energy moves over the area,
showers and thunderstorms will develop from Thursday afternoon into Friday
evening.

Meanwhile, a front extending from the Upper Great Lakes to parts of the
Central Plains will move eastward to just off the Northeast and
Mid-Atlantic Coast by Saturday. The boundary will produce rain with
embedded thunderstorms over parts of the Middle Mississippi Valley on
Friday morning into the early afternoon. As the front moves into the
Northeast and Mid-Atlantic, showers and thunderstorms will develop over
parts of the region late Friday evening into Saturday.

In addition, on Friday morning, a second front will move onshore over the
Pacific Northwest, moving to the Northern Plains by Saturday. The system
will produce rain over parts of the Pacific Northwest from Friday into
late Friday evening. Overnight Friday, wet snow will develop over the
highest elevations of the Cascades. The rain will expand into the Northern
Intermountain Region Friday evening into Saturday.

Moreover, the upper-level ridge over the Four Corners Region will create
high temperatures over Southern California and the Southwest, ranging from
the upper 90s to 110s. Low temperatures will be in the upper 80s to low
90s, providing little relief from the heat overnight. The temperatures
have prompted Excessive Heat Warnings and Heat Advisories over parts of
Southern California and the Southwest.

Record-breaking heat is expected across portions of the Southwest this
week. Moderate to major heat impacts are possible in areas near San
Francisco, Las Vegas, and Los Angeles. Extreme Heat Risk impacts are
forecast for parts of the Southwest. Remember, Heat is the Deadliest
Weather Phenomenon in the U.S.! People spending more time outdoors or in a
building without cooling are at an increased risk of heat-related illness.
Visit www.weather.gov/safety/heat and check local media and government
websites for information on cooling centers.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Wed Oct 02 2024
Valid 12Z Wed Oct 02 2024 – 12Z Fri Oct 04 2024

….There is a Marginal Risk of excessive rainfall over parts of the
Central Gulf Coast on Thursday…

…There is a Critical Risk of fire weather over parts of the Central High
Plains/Central Rockies on Wednesday…

…There are Excessive Heat Warnings and Heat Advisories over parts of
Southern California and the Southwest…

A front extending from the Lower Great Lakes to the Central Appalachians
to the Central Gulf Coast moves eastward to the Northeast and dissipates.
On Wednesday, the front will produce light rain over parts of the Lower
Great Lakes, Central Appalachians, and Mid-Atlantic. The light rain will
end overnight Wednesday. In addition, showers and thunderstorms will
develop over parts of Florida through Friday.

On Thursday, tropical moisture will start to build over the
Central/Eastern Gulf Coast and Florida. Upper-level energy over the
Western Gulf Coast and Northern Gulf of Mexico will move into parts of the
Southeast and Central Gulf Coast, producing moderate to heavy rain over
parts of the Central Gulf Coast. Therefore, the WPC has issued a Marginal
Risk (level 1/4) of excessive rainfall over parts of the Central Gulf
Coast from Thursday into Friday morning. The associated heavy rain will
create localized areas of flash flooding, affecting areas that experience
rapid runoff with heavy rain. Light rain and showers will also develop
over parts of the Southeast/southern Mid-Atlantic on Thursday into Friday.

Meanwhile, a front extending from the Northern Plains to parts of the
Pacific Northwest will move eastward to the Great Lakes and southward to
the Central Plains by Thursday evening. As the boundary continues to move
eastward, light rain will develop over parts of the Middle Mississippi
Valley and expand into the Upper Great Lakes by Friday.

Furthermore, down-slope flow over parts of the Northern/Central Rockies
will create warm air over parts of the Central Rockies, combined with
strong gust wind and dry fuels, which have prompted a Critical Risk of
fire weather over parts of the Central Rockies on Wednesday.

Moreover, the upper-level ridge over the Four Corners Region will create
high temperatures over Southern California and the Southwest, ranging from
the upper 90s to 110s. Low temperatures will be in the upper 80s to low
90s, providing little relief from the heat overnight. The temperatures
have prompted Excessive Heat Warnings and Heat Advisories over parts of
Southern California and the Southwest.

Record-breaking heat is expected across portions of the Southwest this
week. Moderate to major heat impacts are possible in areas near San
Francisco, Las Vegas, and Los Angeles. Extreme Heat Risk impacts are
forecast in Phoenix. Remember, Heat is the Deadliest Weather Phenomenon in
the U.S.! People spending more time outdoors or in a building without
cooling are at an increased risk of heat-related illness. Visit
www.weather.gov/safety/heat and check local media and government websites
for information on cooling centers.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Tue Oct 01 2024
Valid 12Z Tue Oct 01 2024 – 12Z Thu Oct 03 2024

…There is a Marginal Risk of excessive rainfall over parts of the
Mid-Atlantic and Florida on Tuesday…

…There is a Critical Risk of fire weather over parts of the Northern
High Plains on Tuesday…

…There are Excessive Heat Warnings and Heat Advisories over parts of
Southern California and the Southwest…

Upper-level energy over the Mid-Atlantic will slowly advance off the
Eastern Seaboard by late Tuesday night. Lingering moisture and upper-level
energy will produce moderate to heavy rain over parts of the Mid-Atlantic.
Therefore, the WPC has issued a Marginal Risk (level 1/4) of excessive
rainfall over parts of the Mid-Atlantic through Wednesday morning. The
associated heavy rain will create localized areas of flash flooding,
affecting areas that experience rapid runoff with heavy rain.

In addition, showers and thunderstorms will develop over parts of Florida
producing areas of moderate to heavy rain. Therefore, the WPC has issued a
Marginal Risk (level 1/4) of excessive rainfall over parts of Florida
through Wednesday morning. The associated heavy rain will create
localized areas of flash flooding, affecting areas that experience rapid
runoff with heavy rain.

Meanwhile, a front extending from the Upper Great Lakes to the Southern
Plains moves eastward to the Northeast and weakens. On Tuesday, the front
will produce light rain over parts of the Upper Great Lakes and by Tuesday
afternoon, rain will expand along the boundary from the Ohio Valley to the
Tennessee Valley. Light rain moves into the Lower Great Lakes/Central
Appalachians by Wednesday and into the Northeast/Mid-Atlantic by Wednesday
evening. In addition, showers and thunderstorms will develop over parts of
Florida from Tuesday into Thursday.

Further, upper-level ridging over the Northern Intermountain Region into
the Northern Rockies will create warm air associated with down-sloping
air, strong gust wind, and dry fuels, prompting a Critical Risk of fire
weather over parts of the North High Plains on Tuesday.

Elsewhere, a front moving onshore over the Pacific Northwest will move
inland to the Great Lakes by Thursday. The system will produce scattered
showers over parts of the Pacific Northwest on Tuesday.

Moreover, the upper-level ridge over the Four Corners Region will create
high temperatures over Southern California and the Southwest, ranging from
the upper 90s to 110s. Low temperatures will be in the upper 80s to low
90s, providing little relief from the heat overnight. The temperatures
have prompted Excessive Heat Warnings and Heat Advisories over parts of
Southern California and the Southwest.

Record-breaking heat is expected across portions of the Southwest.
Remember, Heat is the Deadliest Weather Phenomenon in the U.S.! People
spending more time outdoors or in a building without cooling are at an
increased risk of heat-related illness. Visit www.weather.gov/safety/heat
and check local media and government websites for cooling center
information.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Mon Sep 30 2024
Valid 12Z Mon Sep 30 2024 – 12Z Wed Oct 02 2024

..There is a Slight Risk of excessive rainfall over parts of the Central
Appalachians/Mid-Atlantic on Monday…

…There is a Critical Risk of fire weather over parts of the
Northern/Central Plains on Monday…

…There are Excessive Heat Warnings and Heat Advisories over parts of
Southern California and the Southwest…

An upper-level low over the Ohio Valley/Central Appalachians will slowly
weaken and move eastward to the Mid-Atlantic by Tuesday, with the energy
moving off the Mid-Atlantic Coast by Tuesday evening. A rich pool of
moisture extends from the Tennessee Valley to the Ohio Valley, and then
the Mid-Atlantic will be impacted by upper-level dynamics to produce heavy
rain over parts of the Central Appalachians/Mid-Atlantic. Therefore, the
WPC has issued a Slight Risk (level 2/4) of excessive rainfall over parts
of the Central Appalachians/Mid-Atlantic through Tuesday morning. The
associated heavy rain will create mainly localized areas of flash
flooding, with urban areas, roads, small streams, and low-lying areas the
most vulnerable. On Tuesday, the threat of excessive rainfall ends. Rain
and showers will continue over parts of the Mid-Atlantic through Tuesday
night.

Meanwhile, a dry front extending from the Northern Plains to the Central
High Plains/Central Rockies will move to the Lower Upper Great Lakes
southwestward to the Southern Plains by Wednesday. On Tuesday, the front
will intersect moisture over the Upper Midwest, producing light rain over
parts of the Upper Great Lakes. By Tuesday afternoon, rain will expand
along the boundary from the Ohio Valley to the Tennessee Valley. Light
rain will move into the Lower Great Lakes/Central Appalachians by
Wednesday. In addition, showers and thunderstorms will develop over parts
of Florida from Monday into Wednesday.

Ahead of the front, an upper-level ridge will extend from the Southwest to
the Northern/Central Plains. The warm air associated with the upper-level
ridge, strong gust wind, and dry fuels have prompted a Critical Risk of
fire weather over the North/Central Plains on Monday.

Moreover, the upper-level ridge over the Four Corners Region will create
high temperatures over Southern California and the Southwest ranging from
the upper 90s to 110s. Low temperatures will be in the upper 80s to low
90s, providing little relief from the heat overnight. The temperatures
have prompted Excessive Heat Warnings and Heat Advisories over parts of
Southern California and the Southwest.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Sun Sep 29 2024
Valid 12Z Sun Sep 29 2024 – 12Z Tue Oct 01 2024

…There is a Slight Risk of excessive rainfall over parts of the Central
Appalachians/Mid-Atlantic on Sunday and Monday…

…There is a Critical Risk of fire weather over parts of the
Northern/Central Plains on Sunday and Monday…

…There are Excessive Heat Warnings over parts of Southeastern California
and the Southwest…

An upper-level low over the Ohio Valley will slowly weaken and move
eastward to the Mid-Atlantic by Tuesday. A rich pool of moisture extends
from the Tennessee Valley to the Ohio Valley, and then the Mid-Atlantic
will be impacted by upper-level dynamics to produce heavy rain over parts
of the Central Appalachians/Mid-Atlantic. Therefore, the WPC has issued a
Slight Risk (level 2/4) of excessive rainfall over parts of the Central
Appalachians/Mid-Atlantic through Monday morning. The associated heavy
rain will create mainly localized areas of flash flooding, with urban
areas, roads, small streams, and low-lying areas the most vulnerable.

On Monday, the threat of excessive rainfall continues, however, over a
slightly smaller area. Once again, the moisture and upper-level energy
will aid in producing heavy rain over parts of the Central
Appalachians/Mid-Atlantic. Therefore, the WPC has issued a Slight Risk
(level 2/4) of excessive rainfall over parts of the Central
Appalachians/Mid-Atlantic from Monday through Tuesday morning. The
associated heavy rain will create mainly localized areas of flash
flooding, with urban areas, roads, small streams, and low-lying areas the
most vulnerable.

Meanwhile, a dry front will move from the Northern Rockies to the Upper
Great Lakes southwestward to the Southern Plains by Tuesday. Ahead of the
front, an upper-level ridge will extend from the Southwest to the
Northern/Central Plains. The warm air associated with the upper-level
ridge, strong gust wind, and dry fuels have prompted a Critical Risk of
fire weather over the North/Central Plains from Sunday through Monday.
The front will produce showers and thunderstorms over parts of the Upper
Great Lakes overnight Monday into Tuesday.

Moreover, the upper-level ridge over the Four Corners Region will create
high temperatures over Southeastern California and the Southwest that will
range from the upper 90s to 110s, and low temperatures will be in the
upper 80s to low 90s, providing little relief from the heat overnight. The
temperatures have prompted Excessive Heat Warnings over parts of
Southeastern California and the Southwest.