Posts by Sig Silber

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Wed Jul 10 2024
Valid 12Z Wed Jul 10 2024 – 12Z Fri Jul 12 2024

…Post-Tropical Cyclone Beryl to bring Severe Thunderstorms, heavy rain
and flooding to parts of the Midwest, eastern Great Lakes, and Northeast
today…

…Dangerous heat and record high temperatures to continue for much of the
West through the end of the work week…

…Major to Extreme HeatRisk over portions of the East Coast today…

Post-Tropical Cyclone Beryl will continue northeastward through Ohio and
into Ontario and rainfall will increase over northern areas of New York
into New England. Thunderstorms could be severe in some parts of the Lower
Great Lakes/interior Northeast, with some tornado potential. The Storm
Prediction Center issued an Enhanced Risk (level 3/5) for these areas as a
result. The flash flooding threat will be greater over parts of
northeastern New York into northern Vermont/New Hampshire, where a
Moderate Risk (at least 40%) of Excessive Rainfall is in effect.
Elsewhere, showers and some thunderstorms are possible over parts of New
Mexico, along the Gulf Coast, and into the Southeast/Mid-Atlantic. A
Slight Risk (at least 15%) of Excessive Rainfall is in effect over
portions of south-central New Mexico where heavy rainfall over the
Sacramento Mountains and adjacent burn scars could trigger Flash Flooding.
Things settle down considerably over the Northeast by Thursday.

In the West, the intense heat will continue for at least a few more days,
with temperatures well above normal and reaching or exceeding daily record
highs over many locations from Mexico to Canada west of the Rockies.
Excessive heat warnings or heat advisories are in effect for much of the
area outside the high mountains, even including the foothills.
Temperatures well into the 100s/110s will be commonplace, resulting in a
widespread Major to Extreme HeatRisk. In addition to the record high daily
temperatures, the early morning lows are also expected to set records
across large portions of the West over the coming few mornings. The
multi-day length and record warm overnight temperatures will continue to
cause heat stress to anyone without adequate cooling and hydration.

Temperatures will be cooler than average along the path of Post-Tropical
Cyclone Beryl thanks to overcast skies and rain. Ahead of its path, the
East Coast will see another day of warm/hot temperatures well into the 90s
from the Mid-Atlantic southward through the Carolinas. The high humidity
values will result in heat index values over 100F for many of these areas.
This will also promote many record high minimum temperatures that only dip
into the mid/upper 70s at night (and near 80 in some urban centers such as
Baltimore and Washington, D.C.). Heat advisories are in effect for much of
the I-95 corridor between the Appalachians and the coast, while Excessive
Heat Warnings are in effect for Philadelphia and the surrounding counties.
By Thursday, temperatures may cool by a couple degrees as the cold front
associated with Beryl reaches the East Coast but may stall across the
region. This could finally bring some much needed rain to the
Mid-Atlantic, with isolated flash flooding possible over parts of the
Virginia/Carolina Tidewater.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Tue Jul 09 2024
Valid 12Z Tue Jul 09 2024 – 12Z Thu Jul 11 2024

…Beryl to bring heavy rain and flooding from the Lower Arkansas River
Valley, northeast into the Middle Mississippi Valley, Lower Ohio Valley
and Lower Great Lakes…

…Record high temperatures to continue into mid week across large
portions of the west coast, while record high minimum temperatures stretch
from the Gulf coast, northeast along the East coast…

Beryl is expected to move steadily northeastward from central Arkansas
today into the Lower Ohio Valley tonight and into the Lower Great Lakes on
Wednesday. While the wind speeds associated with Beryl will continue to
weaken as it moves farther from the Gulf of Mexico, the storm will
continue to be a prolific heavy rain producer as it pushes northeastward.
Widespread heavy rains and thunderstorms are likely along and to the
northeast of the path of Beryl over the next two days with rainfall totals
of 2-5″ from central Arkansas, across southeast Missouri, central to
southern Illinois, Indiana into the southern portions of the L.P. of
Michigan and then over portions of upstate New York and Vermont/New
Hampshire. These amounts are following the 5 to 10+ inches of rain that
fell along the path of Beryl as it pushed inland earlier Monday along the
central Texas Gulf Coast. Severe thunderstorms capable of producing
tornadoes will be possible over portions of the lower Ohio Valley today
followed by the interior Northeast on Wednesday. A higher end Slight Risk
(at least 25%) of Excessive Rainfall leading to Flash Flooding is in
effect for portions of upstate New York into Vermont on Wednesday. Flood
watches are currently in effect along the path of Beryl from northern
Arkansas, northeastward into the southeastern L.P. Michigan, affecting
over 21 million people.

No let up expected to the string of record high temperatures being set
across large portions of the West. The mid to upper-level high that has
been anchoring the record record heat in the West is not expected to
change much over the next several days, as it remains locked in place,
stretching from Southern California/Desert Southwest, northward through
the Great Basin and across the Pacific Northwest and Northern Rockies.
Excessive Heat Warnings, Watches, and Heat Advisories are currently in
effect for nearly all of Washington State, Oregon, California, Idaho,
Nevada and western Arizona. Numerous record high temperatures are
expected across these areas over the next few days where high temperatures
will be anywhere from 10 to as high as 30 degrees above average. In
addition to the record high daily temperatures, the early morning lows are
also expected to set records across large portions of the West over the
coming two mornings. The multi-day length and record warm overnight
temperatures will continue to cause heat stress to anyone without adequate
cooling and hydration.

Elsewhere, much above average temperatures also likely to remain in place
along much of the east over the next few days. While there is not
forecast to be many record high temperatures across the East over the next
few days, numerous record high minimum temperatures are likely from the
eastern Gulf coast, through the Southeast, Mid-Atlantic and into southern
New England. Heat advisories are currently in effect across large portions
of the South, Southeast, Mid-Atlantic and southern New England with this
likely to continue over the next few days. An Excessive Heat Warning is in
effect across portions of southwestern West Virginia for this afternoon
due to the combination of hot temperatures and high humidity create a
dangerous situation in which heat related illnesses are likely.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Mon Jul 08 2024
Valid 12Z Mon Jul 08 2024 – 12Z Wed Jul 10 2024

…Hurricane Beryl to bring very heavy rain, damaging hurricane-force
winds and life-threatening storm surge to the Texas coast today…

…Extreme heat re-focuses over the Desert Southwest and interior Pacific
Northwest; more heat and humidity for the Mid-Atlantic as well…

Hurricane Beryl is expected to track up into the ArkLaTex today.
Life-threatening storm surge and rip currents are likely along much of the
Texas Coast, but especially from Mesquite Bay to Sabine Pass. Residents in
those areas should follow any advice given by local officials and follow
evacuation orders. Damaging hurricane-force winds are also expected for
portions of the Texas Coast around the time of Beryl’s landfall this
morning. A Hurricane Warning is in effect from Mesquite Bay to San Luis
Pass. Severe thunderstorms are likely to occur from the eastern
Texas/western Louisiana coast up through the ArkLaTex today, where a
Slight Risk (level 2/5) and embedded Enhanced Risk (level 3/5) are in
effect. Considerable flash and urban flooding are expected through tonight
across portions of the middle and upper Texas Gulf Coast and eastern
Texas. Minor to isolated major river flooding is also expected. A Moderate
Risk (at least 40%) of Excessive Rainfall leading to Flash Flooding is in
effect for eastern Texas up into the ArkLaTex for today. Please refer to
the National Hurricane Center for more information on Beryl.

A deep and well entrenched upper-level ridge stationed over the West will
support the continuation of an extreme heat wave across the region early
this week. High temperatures in the upper 90s to low 110s will represent
15-30 degree anomalies. Widespread high and low temperature records will
likely be tied or broken over the next couple of days as a result of this
unusual heat. The multi-day length and record warm overnight temperatures
will continue to cause heat stress in people without adequate cooling and
hydration. The heat wave is forecast to shift from California and Oregon
north to Washington and east over the Great Basin and Arizona through
mid-week.

Heavy rainfall and thunderstorms spread into the Mississippi Valley on
Tuesday as Beryl transitions into a Post-Tropical Cyclone. There’s a
Slight Risk (at least 15%) of Excessive Rainfall over portions of northern
Arkansas through southeastern Missouri, far western Kentucky,
southern/central Illinois and far western Indiana. The cold front attached
to Beryl will become quasi-stationary over portions of the central Gulf
Coast and support training rainfall on Tuesday. Thus, a Slight Risk of
Excessive Rainfall is in effect for parts of Louisiana’s central
coastline. Heat and humidity begin to build over the Mid-Atlantic today as
the upper trough that will eventually pick up Beryl directs moisture and
warm air northward across the East Coast. Strong southerly flow and clouds
will contribute to warm overnight temperatures in the 70s. These
temperatures will likely tie or break existing records across much of the
Appalachians and East Coast through midweek.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Sun Jul 07 2024
Valid 12Z Sun Jul 07 2024 – 12Z Tue Jul 09 2024

…Beryl to bring significant impacts to the Texas coast beginning today
before making landfall as a Hurricane tonight…

…Extremely dangerous heat wave continues in the West….

…Focus of severe thunderstorms and heavy rainfall expected to shift
south into Oklahoma today…

…Critical Fire Weather over portions of southern Utah…

The upper pattern across the CONUS will consist of a dome of high pressure
in the West, a digging trough in the Central U.S. and more ridging in the
Southeast heading into the beginning of the work week.

Beryl, which is currently a Tropical Storm, is forecast to strengthen to a
Hurricane before making landfall early Monday morning. Tropical Storm
force winds could develop as early as this evening for the upper Texas
coast. Heavy rainfall, severe thunderstorms, as well as strong rip
currents and coastal inundation from storm surge are the most likely
impacts from Beryl. There’s a Moderate Risk (at least 40%) of Excessive
Rainfall leading to Flash Flooding for portions of the central Texas Coast
from Aransas up to Galveston County today. There’s a Slight Risk of Severe
Thunderstorms along the middle to upper Texas coast with severe wind
gusts, isolated to large hail and a few tornadoes possible. Excessive
Rainfall and Severe Thunderstorm threats spread farther inland through the
ArkLaTex on Monday. Another Moderate Risk of Excessive Rainfall is in
effect from the central/northern Texas coast up into northeast Texas near
the ArkLaTex. Hurricane, Tropical Storm and Storm Surge Warnings are in
effect for portions of the Texas Coast from South Padre Island up through
the Houston metro area. For more information please refer to the National
Hurricane Center.

The extremely dangerous heat wave in the West is forecast to continue and
expand across the Northwest and into the Northern High Plains over the
next few days. Dozens of daily record temperatures are forecast to be tied
or broken into the work week. Highs in the 100s to 110s and lows in the
70s will represent 15-30 degree positive temperature anomalies. The
multi-day nature of the heat and record warm overnight temperatures will
cause heat stress to build in people without adequate cooling and
hydration. In addition to the heat, dry and windy conditions over parts of
southern Utah will contribute to a Critical Fire Weather Risk today.

The digging upper trough over the Central U.S. will push a surface cold
front south through the Central Plains today. An MCS is expected to
develop between the cold front and a warm front lifting up from the
Southern High Plains. This area of convergence will be ripe for severe
thunderstorms and heavy rainfall this afternoon. There are Slight Risks of
Severe Thunderstorms and Excessive Rainfall over portions of northern
Texas, central Oklahoma and southern Kansas, where the MCS is forecast to
produce severe wind gusts and isolated flash flooding. A quasi-stationary
surface front draped across the Southeast will focus scattered to isolated
thunderstorm activity across the region over the next couple days. An
isolated instance of flash flooding cannot be ruled out as a result.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
401 AM EDT Sat Jul 06 2024

Valid 12Z Sat Jul 06 2024 – 12Z Mon Jul 08 2024

…Extremely dangerous heat continues in the West, with heat persisting in
the Eastern U.S….

…Severe thunderstorms and Excessive rainfall possible for portions of
the Central Plains and Lower Mississippi Valley today, then the
Central/Southern Plains on Sunday…

…Beryl is forecast to re-intensify over the southwestern Gulf of Mexico
today and threaten the western Gulf Coast of the U.S. beginning on
Sunday…

…Critical Fire Weather possible over portions of the Upper Great Basin
and Four Corners Regions this weekend…

An amplified upper-level pattern over the CONUS will support record
breaking heat in the West, severe weather and heavy to excessive rainfall
over the Central U.S., and some more heat risk in the
Mid-Atlantic/Southeast this weekend. A staunch upper ridge continues to
promote an intense, widespread and long duration heat wave across the
West. Widespread temperature records are expected to be tied or broken
this weekend with highs in the upper 90s to 110s likely up and down the
West Coast and portions of the Great Basin. These conditions will be
extremely dangerous and potentially deadly if not taken seriously. The
multi-day nature of the heat and record warm overnight temperatures will
cause heat stress to build in people without adequate cooling and
hydration. Excessive Heat Watches, Warnings and Heat Advisories are in
effect for much of the West. Hazardous heat will continue in the
Mid-Atlantic and Southeast today. Heat index values will approach or
exceed 110 degrees at times. Heat Advisories stretch from upstate New York
down the East Coast to the Alabama coast. The intense heat paired with dry
windy conditions will support a Critical Risk of Fires over portions of
southern Idaho today and southern Utah on Sunday.

Elsewhere, an upper-level trough stationed over the Central U.S. will
amplify and dig into the Southern Plains this weekend. At the surface, a
pair of slow moving low pressure systems will focus areas of showers and
thunderstorms across the Great Plains and Mississippi Valley. The Storm
Prediction Center issued a Slight Risk (level 2/5) of Severe Thunderstorms
across parts of the Central Plains this afternoon/evening. Isolated large
hail and severe wind gusts are expected from the Southern High Plains into
the Upper Midwest. Mid-level energy propagating atop a moist, unstable
environment and quasi-stationary front at the surface will support
convection and locally heavy rainfall from central Texas through the
Central Gulf Coast today. There’s a Slight Risk of Excessive Rainfall (at
least 15%) over much of Louisiana. Another round of heavy rainfall could
produce heavy to excessive rainfall for parts of central Oklahoma northern
Texas and southern Kansas on Sunday. A Slight Risk of Excessive Rainfall
is in effect for the aforementioned areas. Some more scattered to isolated
storms will occur over portions of the Northeast today with potential for
isolated Flash Flooding.

Tropical Storm Beryl is forecast to intensify as it moves through the
western Gulf of Mexico today. Beryl is forecast to strengthen into a
Hurricane on Sunday night before making landfall somewhere along the Texas
Coast. The exact location of Beryl’s landfall is uncertain at this point
but what’s most important is that heavy rainfall, strong winds and storm
surge are expected for much of the state’s coastline and portions of the
central Gulf Coast beginning tonight into Sunday. Please refer to the
National Hurricane Center for the latest Beryl forecast track and
intensity.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Fri Jul 05 2024

Valid 12Z Fri Jul 05 2024 – 12Z Sun Jul 07 2024

…Heat is expected to intensify and spread farther up the West Coast this
weekend…

…Oppressive heat and humidity will shift east into the Mid-Atlantic and
Southeast today and Saturday…

…Excessive Rainfall possible over portions of the coastal Mid-Atlantic
down through the Carolinas on Saturday…

…Beryl is forecast to re-intensify over the southwestern Gulf of Mexico
on Saturday and threaten southern Texas…

Dangerous heat is likely to become more widespread in the West today and
Saturday. Today, temperatures will soar into the 100s and 110s over much
of California and southern Oregon. Temperatures will be 15-30 degrees
above average for much of the West Coast today. Widespread temperature
records are expected to be tied or broken. Saturday will likely shape up
to be the hottest day in this heatwave when high temperatures into the
110s will be common across California outside of the cooling effects of
the Pacific Ocean near the coast and the naturally cooler higher
elevations. Numerous record-breaking temperatures can be expected through
the next few days. Locally higher temperatures into the 120s are possible
in the typical hot spots of the Desert Southwest. The triple-digit heat
will expand northward into the Pacific Northwest and parts of the central
Great Basin, with widespread highs rising into the 90s and low 100s. The
duration of this heat is also concerning as scorching above average
temperatures are forecast to linger into next week. Heat impacts can
compound over time, therefore it is important to remain weather aware and
follow the advice of local officials. Heat Watches and Warnings are in
effect for much of the West. This level of heat throughout parts of the
Mojave Desert and Sacramento/San Joaquin valleys of California could pose
a risk to anyone if proper heat safety is not followed. It is imperative
to stay hydrated, out of direct sunlight, and in buildings with sufficient
air-conditioning when possible. It is also equally as important to check
on the safety of vulnerable friends, family, and neighbors.

Meanwhile, oppressive heat and humidity will begin to shift eastward to
the Mid-Atlantic and Southeast for the end of the week. High temperatures
rising into the upper 90s and low 100s are expected, with heat indices
soaring into the 110s across the lower Mississippi Valley. Warm overnight
conditions in the upper 70s and low 80s will offer little relief, leading
to a dangerous situation for those without access to adequate cooling. A
cold front entering the southern Plains is anticipated to offer cooler and
below average temperatures to Oklahoma, much of northern/western Texas,
and the Mid-South today. Above average temperatures are then anticipated
to remain confined to the Southeast and Mid-Atlantic for the start of the
weekend, with afternoon highs into the mid-to-upper 90s.

An active and stormy weather pattern over the central U.S. is expected to
bring heightened chances for severe thunderstorms and heavy rainfall,
which could impact holiday gatherings through early this weekend. A
developing area of low pressure over the Northern Plains is forecast to
team up with a lingering frontal boundary stretching from the lower Great
Lakes to the southern Plains to trigger some meteorological fireworks.
Thunderstorm chances span from the Southern Plains/Rockies to the
Middle/Upper Mississippi Valley and also eastward to the Ohio Valley and
Mid-Atlantic. Flash flooding will remain a concern throughout the upper
Midwest as well due to yet another round of thunderstorms overlapping
areas dealing with ongoing river flooding and saturated soils, with
scattered flash flooding also possible between the Ohio Valley and
southern Plains. Today, thunderstorms will continue to progress eastward
with the frontal boundary into much of the eastern third of the country.
Isolated strong to severe storms and flash flooding are possible. The
greatest threat for damaging wind gusts associated with these storms will
be across the upper Ohio Valley. Elsewhere, daily thunderstorm chances
associated with daytime heating are possible along the Gulf Coast and
Florida. Scattered showers and thunderstorms are also possible throughout
the north-central U.S. this weekend as upper troughing remains over the
region. There’s a Slight Risk for Excessive Rainfall leading to Flash
Flooding along a stalled out frontal boundary over portions of
southeastern Virginia down through coastal Carolina on Saturday. Residents
and visitors located within areas expecting severe weather and/or heavy
rainfall are advised to remain weather aware, have multiple ways to
receive warnings, and never drive across flooded roadways.

As we head into the weekend, interests along the western Gulf of Mexico
should pay attention to the future progress of Hurricane Beryl, currently
located in the western Caribbean Sea. Beryl is forecast to weaken into a
tropical storm as it traverses the Yucatan Peninsula on Friday before
emerging into the southwestern Gulf of Mexico on Saturday. Beryl has an
opportunity to re-intensify over the Gulf and turn more northwest toward
the southern tip of Texas by the end of this forecast period Saturday
evening.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Thu Jul 04 2024
Valid 12Z Thu Jul 04 2024 – 12Z Sat Jul 06 2024

…Extremely dangerous and record-breaking heatwave to impact much of the
West through this weekend…

…One more day of oppressive heat and humidity across the Southern Plains
and Lower Mississippi Valley today before steamy temperatures focus over
the Mid-Atlantic and Southeast…

…Flash flooding and severe thunderstorms possible throughout parts of
the Midwest, Ohio Valley, and Southern Plains this Independence Day…

A significant and extremely dangerous heatwave is set to build throughout
the West to end this week and into the extended holiday weekend, with
several days of record-breaking heat forecast. An upper-level high
situated just off the West Coast today is forecast to strengthen and
reorient directly over the western U.S. by Friday. This pattern will
support well above average temperatures over California and into southwest
Oregon today before heat spreads further throughout the western U.S. this
weekend. High temperatures are forecast to reach into the 105-115F range
for interior California away from the immediate coastline, as well as
across much of the Desert Southwest. Locally higher temperatures into the
120s are possible in the typical hot spots of the Desert Southwest.
Searing afternoon temperatures will also spread into the Northwest and
parts of the central Great Basin, with widespread highs rising into the
90s and low 100s. Dozens of daily record high temperatures are possible,
expressing the rarity of this early-July heatwave. The duration of this
heat is also concerning as scorching above average temperatures are
forecast to linger into next week. Heat impacts can compound over time,
therefore it is important to remain weather aware and follow the advice of
local officials. This level of heat throughout parts of the Mojave Desert
and Sacramento/San Joaquin valleys of California could pose a risk to
anyone if proper heat safety is not followed. It is imperative to stay
hydrated, out of direct sunlight, and in buildings with sufficient
air-conditioning when possible. It is also equally as important to check
on the safety of vulnerable friends, family, and neighbors.

Oppressive heat and humidity will also be found throughout the southern
Plains and lower Mississippi Valley today, while expanding eastward to the
Mid-Atlantic and Southeast for the end of the week. High temperatures
rising into the upper 90s and low 100s are expected, with heat indices
soaring into the 110s across the lower Mississippi Valley. Warm overnight
conditions in the upper 70s and low 80s will offer little relief, leading
to a dangerous situation for those without access to adequate cooling. A
cold front entering the southern Plains is anticipated to offer cooler and
below average temperatures to Oklahoma, much of northern/western Texas,
and the Mid-South by Friday. Above average temperatures are then
anticipated to confine to the Southeast and Mid-Atlantic for the start of
the weekend, with afternoon highs into the mid-to-upper 90s. If planning
to spend an extended amount of time outdoors this Fourth of July, be sure
to use caution and act quickly if you see signs of heat-related illnesses.

An active and stormy weather pattern over the central U.S. is expected to
create chances for severe thunderstorms and heavy rainfall, which could
impact holiday gatherings through early this weekend. A developing area of
low pressure over the northern Plains is forecast to progress into the
upper Midwest by tonight and team up with a lingering frontal boundary
stretching from the lower Great Lakes to the southern Plains to trigger
some meteorological fireworks. Thunderstorm chances span from the southern
Plains/Rockies to the middle/upper Mississippi Valley and also eastward to
the Ohio Valley and Mid-Atlantic. However, the greatest threat for strong
to severe thunderstorms will be near/along the frontal boundary through
parts of the middle/upper Mississippi Valley and southern Plains. Damaging
wind gusts and frequent lightning are the most likely weather hazard
associated with these Fourth of July storms. Flash flooding will remain a
concern throughout the upper Midwest as well due to yet another round of
thunderstorms overlapping areas dealing with ongoing river flooding and
saturated soils, with scattered flash flooding also possible between the
Ohio Valley and southern Plains. On Friday, thunderstorms will continue to
progress eastward with the frontal boundary into much of the eastern third
of the country. Isolated strong to severe storms and flash flooding are
possible. The greatest threat for damaging wind gusts associated with
these storms will be across the upper Ohio Valley. Elsewhere, daily
thunderstorm chances associated with daytime heating are possible along
the Gulf Coast and Florida. Scattered showers and thunderstorms are also
possible throughout the north-central U.S. this weekend as upper troughing
remains over the region. Residents and visitors located within areas
expecting severe weather and/or heavy rainfall are advised to remain
weather aware, have multiple ways to receive warnings, and never drive
across flooded roadways.

Have a safe Independence Day!

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Wed Jul 03 2024
Valid 12Z Wed Jul 03 2024 – 12Z Fri Jul 05 2024

…Dangerous heatwave to impact much of the West, while oppressive heat
and humidity also swelter areas from the Southern Plains to the
Mid-Atlantic…

…Flash flooding and severe thunderstorms possible over the next few days
across portions of the Plains, Midwest, and Ohio Valley…

Record-breaking and dangerous heat is forecast to make this Fourth of July
week a scorcher across much of the West and from the southern Plains to
the Mid-Atlantic. Over 110 million residents are currently under
heat-related watches, warnings, and advisories throughout 21 states as of
early this morning. An upper-level high situated just off the West Coast
today is forecast to strengthen and reorient directly over the western
U.S. by the end of the week. This pattern will support well above average
temperatures over California today before heat spreads further along the
West Coast by the end of the week. High temperatures are forecast to reach
into the 105-115F range throughout interior California away from the
immediate coastline, as well as into much of the Desert Southwest.
Afternoon temperatures will also begin to increase across much of Oregon
and Washington by Thursday and Friday, with widespread highs soaring into
the 90s. Dozens of record highs are possible, expressing the rarity of
this early-July heatwave. The duration of this heat is also concerning as
scorching above average temperatures are forecast to linger into next
week. Heat impacts can compound over time, therefore it is important to
remain weather aware and follow the advice of local officials. This level
of heat throughout the Sacramento and San Joaquin valleys of California
could pose a risk to anyone if proper heat safety is not followed. This
includes staying hydrated, out of direct sunlight, and in buildings with
sufficient air-conditioning. It is also very important to check on the
safety of vulnerable friends, family, and neighbors.

Oppressive heat and humidity will also be found throughout the southern
Plains and lower Mississippi Valley into the Independence Day holiday
while also expanding eastward to the Mid-Atlantic for the end of the week.
High temperatures rising into the upper 90s and low 100s are expected,
with heat indices soaring into the 110s across the lower Mississippi
Valley. Warm overnight conditions in the upper 70s and low 80s will offer
little relief, leading to a dangerous situation for those without access
to adequate cooling. A cold front entering the southern Plains is
anticipated to offer cooler and below average temperatures to Oklahoma and
much of northern/western Texas by Friday.

An active and stormy weather pattern over the central U.S. is expected to
create chances for severe thunderstorms and heavy rainfall, which could
impact holiday gatherings this week. A developing area of low pressure
over the central High Plains today forecast to progress into the upper
Midwest by Thursday along with a lingering frontal boundary stretching
from the lower Great Lakes to the central Plains are anticipated to be the
triggers for some meteorological fireworks. For today, the best chances
for scattered flash flooding due to thunderstorms capable of producing
intense rainfall rates is forecast between eastern Kansas and the Ohio
Valley along the aforementioned frontal boundary. Instances of severe
weather (mainly associated with damaging wind gusts) are also possible,
with chances for severe storms also located in parts of the
northern/central High Plains closer to the developing low pressure system.
By Independence Day, thunderstorm chances span from the southern
Plains/Rockies to the middle/upper Mississippi Valley and also eastward to
the Ohio Valley and Mid-Atlantic. However, the greatest threat for strong
thunderstorms turning severe resides over parts of eastern Kansas,
northeast Oklahoma, and southern/central Missouri. Damaging wind gusts and
frequent lightning are the most likely weather hazard associated with
these Fourth of July storms, with isolated strong storms also possible
into the Midwest, Ohio Valley, and Mid-Atlantic. Flash flooding will
remain a concern throughout the upper Midwest as well due to yet another
round of thunderstorms overlapping areas dealing with ongoing river
flooding and saturated soils. Portions of southern Minnesota, eastern
South Dakota, western Wisconsin, and northern Iowa currently have the
highest probabilities (70-90%) for at least 1 inch of rain on Thursday.
Residents and visitors located within areas expecting severe weather
and/or heavy rainfall this week are advised to remain weather aware, have
multiple ways to receive warnings, and never drive across flooded
roadways.

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Tue Jul 02 2024
Valid 12Z Tue Jul 02 2024 – 12Z Thu Jul 04 2024

…Dangerously hot conditions to impact much of the southern Plains, lower
Mississippi Valley, and western U.S. this week…

…Severe thunderstorms and flash flooding possible over portions of the
Midwest through midweek…

…Unsettled weather with localized flash flooding chances continue across
the Southeast and southern Rockies…

Over 60 million residents are currently under heat-related watches,
warnings, and advisories this morning as early-July heat swelters much of
the south-central and western United States. The weather pattern
responsible for the potentially record-breaking heat includes upper-level
ridging just off the West Coast and and a separate upper ridge over the
south-central U.S. today before sliding to the east by midweek. For the
southern Plains, high temperatures are forecast to soar into the upper 90s
and low 100s. When combined with elevated humidity levels, heat indices
are forecast to rise into the 110s across the lower Mississippi Valley and
Gulf Coast. Excessive Heat Warnings and Heat Advisories currently span
from Kansas/Missouri to the Gulf Coast States. After enjoying a refreshing
start to the workweek, the Midwest and East Coast can expect a gradual
return to muggy summer warmth by Wednesday as surface high pressure
reorients itself off the East Coast and ushers in southerly flow. Extreme
heat building throughout the West Coast and more specifically interior
California this week will be particularly dangerous for those without
effective cooling. High temperatures away from the immediate coastline are
forecast to reach into the 105-115F range, which could break numerous
daily records in the San Joaquin and Sacramento Valleys. Heat begins to
build northward on Independence Day as highs into the 90s reach Oregon and
interior Washington. Excessive Heat Warnings, Watches, and Heat Advisories
go into effect today for some and stretch from southwest Washington to the
Desert Southwest. The duration of this heat wave is concerning as the
current forecast keeps scorching conditions in place through at least the
end of the week. This magnitude and duration of heat could pose a danger
to the public if proper heat safety is not followed. This includes staying
hydrated, out of direct sunlight, and in properly air-conditioned
buildings. Additionally, it is very important to check on vulnerable
friends, family, and neighbors to confirm their safety.

Active and stormy weather associated with a few storm systems progressing
from the northern Rockies to the Midwest this week will create fireworks
of their own this holiday week. Initially, a cold front swinging from the
upper Midwest to the Great Lakes by early Wednesday is forecast to spark
numerous thunderstorms from northeast Kansas to central Wisconsin. Some
storms could turn severe and produce damaging wind gusts, a few tornadoes,
and large hail from northeast Kansas to southern Iowa. This area is
highlighted by the Storm Prediction Center as having an Enhanced Risk
(level 3/5) of severe weather. Thunderstorms are also expected to contain
intense rainfall rates as elevated levels of atmospheric moisture content
remain in place. Flood Watches have been issued for much of Iowa, with the
threat of scattered flash floods also encompassing much of the Midwest
today. For areas experiencing swollen rivers from prior rainfall, any
additional heavy rain could exacerbate flooding concerns. By Wednesday, a
cold front is forecast to stretch from the lower Great Lakes to the
central/southern Plains and provide a focus for additional potent
thunderstorms across the mid-Mississippi Valley. Once again thunderstorms
are expected to produce the potential for damaging wind gusts and flash
flooding. A separate area of potentially organized convection may impact
the central High Plains, where a greater threat for large hail and
tornadoes exists. The Fourth of July will feature the aforementioned
frontal boundary lingering over the Ohio Valley and lifting as a warm
front over the central Plains as an area of low pressure ejects off the
High Plains. This will lead to shower and thunderstorm chances from the
northern Plains and Midwest to the Ohio Valley and Mid-Atlantic, with the
highest chances for severe weather extending from eastern Kansas to
central/southern Missouri.

Continued sufficient moisture content over the Southwest and southern
Rockies will also aid in the development of daily showers and
thunderstorms capable of producing localized instances of flash flooding
through midweek. Regions most likely to be affected by scattered downpours
include southeast Arizona and New Mexico, with burn scars and sensitive
terrain the most at risk for flash flooding. Meanwhile, a dying stationary
front entering the Southeast from the western Atlantic will also aid in
daily widely scattered thunderstorms across the Gulf Coast, Florida, and
the Southeast coastline/southern Georgia.