weather

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Wed Jul 24 2024
Valid 12Z Wed Jul 24 2024 – 12Z Fri Jul 26 2024

…Major to locally extreme Heat Risk will expand across the northern High
Plains as heat gradually becomes less intense over the Central Valley of
California and the Great Basin…

…Scattered showers and thunderstorms will extend across the southern
tier states to the East Coast with heavy rain possible along the Texas
coast today…

…A low pressure wave will bring a round of showers and thunderstorms
across the Great Lakes today and across New England on Thursday…

…Monsoonal thunderstorms continue across the Great Basin and into the
Four Corners region with threats of localized flash flooding while fire
weather danger emerges over the interior Northwest…

A slow-to-evolve summertime weather pattern will continue across much of
the U.S. mainland while a more progressive Pacific cold front sweeps
across the northwestern part of the country through the next couple of
days. Under this weather pattern, unsettled weather and relatively cool
temperatures for July will continue across the eastern half of the country
as the ongoing heat wave over the western U.S. gradually becomes less
intense with the arrival of the Pacific cold front. The stronger forcing
associated with this front will push the heat dome east of the Great
Basin, resulting in the expansion of major to locally extreme Heat Risk
across the northern High Plains through the next couple of days. High
temperatures are forecast to reach well up into the 100s to near 110 at
the hottest location over the northern High Plains through Thursday with
little to no rainfall expected. Meanwhile, the heat will gradually become
less intense over the Central Valley of California and the Great Basin
with time. Please continue to practice heat safety as the heat spreads
into the northern High Plains.

By Thursday night into Friday morning, the cold front will make its way
through the northern Rockies into the High Plains will cooler air arriving
but with very little moisture to work with. Meanwhile, lightning
associated with dry thunderstorms triggered by the passage of the cold
front will result in critical fire danger over the interior northwestern
U.S. In addition, monsoonal thunderstorms will continue across the Great
Basin today and become more numerous over the Four Corners region Thursday
into Friday with the threat of localized flash flooding over the next
couple of days.

In contrast to the heat in the West, cooler than normal temperatures will
prevail across the mid-section of the country to portions of the eastern
U.S. where a stalled front will keep plenty of clouds along with scattered
thunderstorms. These thunderstorms are not expected to be severe but they
could result in localized flooding issues from time to time across the
southern tier states as well as up and down the East Coast. A coastal
front interacting with a broad upper-level southwesterly flow could set
off heavy rain and thunderstorms near the Texas coast into southwestern
Louisiana where flash flooding is possible. Therefore, a slight risk of
flash flooding is posted from southeast Texas into portions of the lower
Mississippi Valley while another is in effect from the interior portions
of the Southeast into the Mid-Atlantic farther up along the stationary
front through the next couple of days.

Farther north, a low pressure wave developing along a cold front dipping
into the northern tier states will bring additional thunderstorms across
the Great Lakes today. By Thursday, the Great Lakes should clear out from
the rain but northern New England will see an increasing chance of showers
and thunderstorms as the low pressure wave approaches from the west.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Tue Jul 23 2024
Valid 12Z Tue Jul 23 2024 – 12Z Thu Jul 25 2024

…Major to locally extreme Heat Risk will expand across the northern High
Plains as heat gradually becomes less intense over the Central Valley of
California and the Great Basin…

…Scattered showers and thunderstorms will affect a large section of the
eastern half of the U.S. with heavy rain emerging near the Texas coast on
Wednesday...

…Monsoonal thunderstorms continue across the Great Basin and into the
Four Corners region with threat of localized flash flooding…

A slow-to-evolve summertime weather pattern will continue across much of
the U.S. mainland as a more progressive Pacific cold front sweeps across
the northwestern part of the country through the next couple of days.
Under this weather pattern, unsettled weather and relatively cool
temperatures for July will continue across the eastern half of the country
as the ongoing heat wave over the western U.S. will gradually become less
intense with the arrival of the Pacific cold front. The stronger forcing
associated with this front will push the heat dome east of the Great
Basin, resulting in the expansion of major to locally extreme Heat Risk
across the northern High Plains through the next couple of days. High
temperatures are forecast to reach well up into the 100s over the northern
High Plains through Thursday with little to no rainfall expected.
Meanwhile, the heat will gradually become less intense over the Central
Valley of California and the Great Basin with time. Please continue to
practice heat safety in the western U.S. and as the heat spreads into the
northern High Plains.

In contrast, cooler than normal temperatures will prevail across the
mid-section of the country and into portions of the eastern U.S. where a
stalled front will keep plenty of clouds along with scattered
thunderstorms. These thunderstorms are not expected to be potent but they
could result in localized flooding issues from time to time across the
southern tier states and up and down the East Coast. A slight risk of
flash flooding is anticipated for areas just inland from the western Gulf
states for today from Texas to central Mississippi. By Wednesday, a
coastal front could set off heavy rain and thunderstorms near the Texas
coast into southwestern Louisiana where flash flooding is possible.
Farther north, another cold front from eastern Canada dipping into the
northern tier states will bring additional thunderstorms across the Great
Lakes to New England through Wednesday. By Thursday morning, the Great
Lakes should clear out from the rain but northern New England will see an
increasing chance of showers and thunderstorms as a low pressure wave
approaches from the west. Meanwhile, monsoonal thunderstorms will
continue across the Great Basin and the Four Corners region with the
threat of localized flash flooding for the next couple of days.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Mon Jul 22 2024
Valid 12Z Mon Jul 22 2024 – 12Z Wed Jul 24 2024

…Major to locally extreme Heat Risk expected to expand from the Great
Basin into the northern High Plains by Wednesday as well as over portions
of the Central Valley of California…

….Scattered thunderstorms across the southern Plains to the Southeast
today near a stalled front will gradually shift toward the East Coast as
another front will spread additional thunderstorms across the Great Lakes
to New England Tuesday and Wednesday…

…Monsoonal thunderstorms continue across the Great Basin and into the
Four Corners region with threat of localized flash flooding…

A slow-to-evolve summertime weather pattern continues across the U.S.
mainland as we head into late July. This weather pattern will sustain the
ongoing heat wave across the western U.S. while maintaining cooler than
normal temperatures across the mid-section of the country and into
portions of the East Coast. The prolonged nature of the heat in the West
will keep the Heat Risk at major to locally extreme levels across portions
of the Central Valley of California, and the Great Basin today where
another afternoon of triple digit high temperatures is expected.
Meanwhile, a Pacific cold front will set things in motion a bit as the
front moves inland across the Pacific Northwest through the next couple of
days. Triple-digit high temperatures will then expand eastward into
northern High Plains by Wednesday ahead of the front while 110s will
persist across the Desert Southwest and 100s in the Central Valley of
California. Please continue to practice heat safety in this persistent
and prolonged heat wave in the western U.S.

In contrast, cooler than normal temperatures will prevail across the
mid-section of the country and into portions of the eastern U.S. where a
stalled front will keep plenty of clouds along with scattered
thunderstorms. These thunderstorms are not expected to be potent but they
could result in localized flooding issues from time to time across the
southern tier states. The upper-level pattern and instability that
support these thunderstorms from the southern Plains to the Southeast
today will gradually expand northeastward into the eastern U.S. on Tuesday
and then generally affect areas from across the Deep South into much of
the East Coast by Wednesday. Another cold front from eastern Canada will
dip into the northern tier states, bringing additional thunderstorms
across the Great Lakes to New England Tuesday and Wednesday. Meanwhile,
monsoonal thunderstorms will continue across the Great Basin and the Four
Corners region with the threat of localized flash flooding for the next
couple of days.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Sat Jul 20 2024
Valid 12Z Sat Jul 20 2024 – 12Z Mon Jul 22 2024

…A break in the heat continues for much of the eastern two-thirds of the
country but heat will intensify in the interior Pacific Northwest through
this weekend…

…Scattered thunderstorms continue across the South and Southeast as
monsoonal thunderstorms linger across the Four Corners region…

…Scattered thunderstorms over the central Plains today will gradually
shift in the southern Plains by Monday while a cold front will bring new
rounds of thunderstorms across the northern tier states…

A cool air mass settling in across the eastern two-thirds of the country
will offer an extended reprieve from the heat through the next few days.
Afternoon high temperatures will only reach into the 70s and 80s today
from the northern and central Plains eastward through the Atlantic coast
with the exception of the Sunshine State and the coastal plain of Georgia
and South Carolina where highs will remain in the 90s. Texas will have
highs into the 90s to near 100 this afternoon but will cool down into the
70s and 80s by Monday. In contrast, the heat across the western U.S. is
expected to persist, with high temperatures once again exceeding 100
degrees across much of the region. The interior Pacific Northwest will
feel the heat intensify, with afternoon readings possibly reaching 110
degrees at the hottest locations by Sunday afternoon along with little
overnight relief. Daily highs across the Southwest will generally hover
in the 110s. Please continue to practice heat safety in this persistent
and prolonged heat wave in the western U.S. through the next couple of
days. A Pacific cold front will approach the West Coast on Monday,
lowering the heat only slightly for inland sections.

The upper level pattern will be slow to change across the lower 48 through
the next few days. A nearly stationary front will remain draped across the
South and into the Mid-Atlantic region, keeping the cooler air north of
the boundary and the warm, moist air to the south. The front will also
help focusing and triggering scattered thunderstorms from the Gulf Coast
to the Southeast through the next few days. For the Southwest/Four
Corners region, monsoonal moisture will continue to support on-and-off
thunderstorms through the weekend. These storms will keep an elevated
threat for isolated to scattered flash flooding and severe weather, which
may result from the strongest of the storms. Meanwhile, scattered
thunderstorms over the central Plains today will gradually shift into the
southern Plains by Monday as a weak low pressure wave slowly digs
southward. Across the northern tier states, a cold front arriving from
central Canada will bring new rounds of thunderstorms from the northern
Plains through northern New England during the next couple of days.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Fri Jul 19 2024
Valid 12Z Fri Jul 19 2024 – 12Z Sun Jul 21 2024

…A break in the heat is expected for much of the eastern two-thirds of
the country but triple-digit heat will continue in the West through this
weekend…

…Scattered thunderstorms will be confined across the South and Southeast
as monsoonal thunderstorms linger across the Four Corners region…

…Strong to severe thunderstorms possible today over the north-central
Plains…

A cool air mass arriving from central Canada is bringing a welcome relief
to the heat and humidity into the northeastern quadrant of the country
today. Temperatures as high as the 100s a couple of days ago in the
Mid-Atlantic will only recover to around 90 degrees this afternoon with
lower humidity. On the other hand, the heat across the western U.S. is
expected to persist through this weekend, with high temperatures once
again exceeding 100 degrees across much of the region. In fact, the heat
is forecast to intensify over the interior Pacific Northwest, with
readings possibly reaching 110 degrees at the hottest locations by Sunday
afternoon along with little overnight relief. Meanwhile, high
temperatures well into the 110s will be common across the Desert
Southwest. Please continue to practice heat safety in this persistent and
prolonged heat wave in the western U.S. throughout this coming weekend.

The upper-level pattern that supports the heat the West and the cooler
weather across the central to eastern U.S. will be slow to evolve through
the next few days. A front that separates the cool air from the warm and
moist air along the Gulf Coast will remain stationary across the South.
Scattered thunderstorms will be confined in the warm sector across the
South and Southeast where they will linger through the weekend.
Meanwhile, monsoonal moisture will support thunderstorms across the Four
Corners region, lingering on-and-off through the weekend. Isolated to
scattered flash flooding and severe weather may result from the strongest
storms. Farther north, a weak low pressure wave will likely trigger
thunderstorms which could become strong to severe over the north-central
Plains today into tonight. Additional thunderstorms are expected to track
farther east toward Iowa and Missouri during the weekend.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Thu Jul 18 2024
Valid 12Z Thu Jul 18 2024 – 12Z Sat Jul 20 2024

…There is a Slight Risk of severe thunderstorms over parts of the
southern Mid-Atlantic on Thursday…

…There is a Slight Risk of excessive rainfall over parts of the southern
Mid-Atlantic, Southern Plains/Lower Mississippi Valley, and Southern High
Plains/Southern Rockies on Thursday and over the southern Mid-Atlantic and
Southern Rockies on Friday…

…There are Excessive Heat Warnings/Watches and Heat Advisories over
parts of the Pacific Northwest into parts of California/Southwest…

A front extending from Northern New England to the Mid-Atlantic and then
southwestward to the Central Gulf Coast and western Texas will move off
the Northeast and Mid-Atlantic Coast by Friday. Also, the southern half of
the boundary will linger near the Southeast and across the Gulf Coast
States through Friday evening. The lingering boundary will produce
showers and severe thunderstorms over parts of the southern Mid-Atlantic.
Therefore, the SPC has issued a Slight Risk (level 2/5) of severe
thunderstorms over parts of the southern Mid-Atlantic through Friday
morning. The hazards associated with these thunderstorms are frequent
lightning, severe thunderstorm wind gusts, hail, and a minimal threat of
tornadoes.

In addition, the showers and thunderstorms will create heavy rain over
parts of the southern Mid-Atlantic. Therefore, the WPC has issued a Slight
Risk (level 2/4) of excessive rainfall over parts of the southern
Mid-Atlantic through Friday 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.

A Second area of heavy rain will develop along the front over parts of the
Southern Plains/Lower Mississippi Valley. Therefore, the WPC has issued a
Slight Risk (level 2/4) of excessive rainfall over parts of the Southern
Plains/Lower Mississippi Valley through Friday 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. Moreover, tropical moisture and upper-level impulses will
produce showers and thunderstorms over parts of the Gulf Coast to the
Southeast.

Further, a third area of heavy rain will develop over parts of the
Southern High Plains/Southern Rockies. Therefore, the WPC has issued a
Slight Risk (level 2/4) of excessive rainfall over parts of the Southern
High Plains/Southern Rockies through Friday morning. The associated heavy
rain will create mainly localized areas of flash flooding, with urban
areas, roads, small streams, low-lying areas, and burn scars the most
vulnerable.

In addition, moisture over the Southwest and daytime heating will produce
showers and thunderstorms over parts of the Great Basin and Southwest from
the late afternoon into late evening. Additionally, on Thursday,
upper-level impulses going over an upper-level ridge over the Northern
Rockies/Northern High Plains and moisture will produce scattered showers
and thunderstorms over parts of the Northern/Central Rockies.

On Friday, the tropical moisture and nearby boundary will produce showers
and thunderstorms over the Central Gulf Coast to the Southeast and
southern Mid-Atlantic. Some showers and thunderstorms will create heavy
rain over parts of the southern Mid-Atlantic. Therefore, the WPC has
issued a Slight Risk (level 2/4) of excessive rainfall over parts of the
southern Mid-Atlantic from Friday through Saturday 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.

Furthermore, monsoonal moisture and daytime heating will aid in producing
showers and thunderstorms over parts of the Southwest, Great Basin, and
Central/Southern Rockies from the late afternoon into late evening. An
area of showers and thunderstorms will create heavy rain over parts of the
Southern Rockies/High Plains. Therefore, the WPC has issued a Slight Risk
(level 2/4) of excessive rainfall over parts of the Southern
Rockies/Southern High Plains from Friday through Saturday morning. The
associated heavy rain will create mainly localized areas of flash
flooding, with urban areas, roads, small streams, low-lying areas, and
burn scars the most vulnerable.

Moreover, the upper-level energy moving out of the Northern Rockies into
the Northern/Central Plains will produce showers and strong to severe
thunderstorms with areas of heavy rain. Therefore, the SPC has issued a
Marginal Risk (level 1/5) of severe thunderstorms over parts of the
Northern/Central High Plains from Friday through Saturday morning. The
hazards associated with these thunderstorms are frequent lightning, severe
thunderstorm wind gusts, hail, and a minimal threat of tornadoes.
Additionally, the WPC has issued a Marginal Risk (level 1/4) of excessive
rainfall over parts of the Northern/Central Plains from Friday through
Saturday morning. The associated heavy rain will create localized areas
of flash flooding, affecting areas that experience rapid runoff with heavy
rain.

Meanwhile, upper-level ridging will build over the Northern Rockies to the
Southwest, spawning Excessive Heat Warnings/Watches and Heat Advisories
over parts of the Pacific Northwest from Thursday into Saturday. Moreover,
the upper-level ridge has prompted Excessive Heat Watches and Heat
Advisories over parts of California and the Southwest. The ridging will
create widespread high temperatures in the 90s to 100s followed by little
overnight relief, with lows in the upper 60s to 70s representing a 20-35
degree departure from average for many areas. The multi-day nature of this
event will create dangerous conditions, particularly for people who are
especially vulnerable to the effects of heat, such as young children,
older adults, people with chronic medical conditions, and pregnant women.