Weather Prediction Center

National Oceanic and Atmospheric Administration

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
356 AM EDT 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.

Snell


Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
257 AM EDT Tue Jul 2 2024

Valid 12Z Fri Jul 5 2024 - 12Z Tue Jul 9 2024

***Major heatwave expected for the lower elevations of California
and the Desert Southwest next week, and Beryl eventually headed
for the Western Gulf***

...Overview...

The main thing making weather headlines during this forecast period
will the intense and prolonged heatwave encompassing much of
California and extending into the lower elevations of the Desert
Southwest. Hot and humid conditions will also continue for much of
the southern states and extending to the East Coast. A low pressure
system is forecast to cross the Upper Midwest and bring a round of
heavy rain and storms to the Great Lakes on Friday, and additional
storms near the trailing frontal boundary across portions of the
Southern Plains and extending east to the Ohio Valley and the Mid-
Atlantic region. The track of Hurricane Beryl is expected to enter
the Bay of Campeche and the Western Gulf by Saturday with rainfall
chances increasing for portions of southern Texas by the weekend.


...Guidance/Predictability Assessment...

The 00Z model guidance suite indicates good overall synoptic scale
agreement across the Continental U.S. to close out the work week,
and better agreement on the massive upper ridge building over the
West Coast, potentially reaching 600dm. The guidance suggests this
ridge should slowly move east over the southern Intermountain West
by next Tuesday/Wednesday. Meanwhile, a general trough axis
situated over the north-central U.S. should be anchored in place by
another ridge axis over the western Atlantic Ocean. A general
deterministic model blend sufficed as a good starting point in the
forecast process for Friday/Saturday, and then increased the
ensemble means to about 40% by next Tuesday.

The latest forecast from the National Hurricane Center has
Hurricane Beryl reaching the Yucatan Peninsula around Friday
morning, and then emerging over the Bay of Campeche by Saturday,
followed by more of a northwestward turn. There has been a recent
trend in the guidance for a more northward track by the time it
enters the western Gulf, which could result in deteriorating
weather conditions for southern Texas. The trough over the Central
U.S. will be a big factor in determining the eventual track.
Beryl's
track will continue to be closely monitored over the next several
days, and the NHC has additional information pertaining to this.


...Weather/Hazards Highlights...

Heavy rain with embedded thunderstorms are likely to continue
across northern Wisconsin and into the Upper Peninsula of Michigan
going into Friday as the developing surface low tracks across the
region, and a Marginal Risk will remain there for the Day 4 period.
Farther south, a corridor of heavy showers and storms is likely
from northern Texas to the Tennessee River Valley, and a Marginal
Risk area is also valid here for Friday. This has trended more
southward compared to yesterday's forecast. Looking ahead to
Saturday, there is enough of a model signal to support a planned
Marginal Risk area for portions of the Mid-Atlantic, where some
slow moving thunderstorms are likely to develop in the vicinity of
a slow moving frontal boundary. Some of the outer rain bands of
Beryl could be approaching southern Texas by late Saturday and
into early Sunday, but generally not expected to be heavy enough by
that time to warrant any risk areas. This could change going into
Sunday, especially if the track trends farther north in later
forecast updates, so stay tuned!

It will continue to remain hot and humid across Texas and extending
eastward across the Deep South and into the Southeast for the end
of the week and into next weekend, with highs in the middle to
upper 90s and dewpoints well into the 70s. It will also be getting
very hot for the inland lower elevations of California and into the
Arizona Deserts with widespread 105-115 degree readings likely,
and locally higher for the normally warmer locations. Daily
temperatures records may be tied or broken in many cases. The heat
likely expands across inland portions of Washington, Oregon, and
much of the Intermountain West by the Sunday-Tuesday time period,
with 100+ degree highs likely for the lower valley locations.

Hamrick


Additional 3-7 Day Hazard information can be found on the WPC
medium
range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast (QPF), excessive rainfall
outlook (ERO), winter weather outlook (WWO) probabilities, heat
indices, and Key Messages can be accessed from:

https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw

Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
325 AM EDT Tue Jul 2 2024

Valid 00Z Wed Jul 3 2024 - 00Z Wed Jul 10 2024

A relatively uneventful weather pattern is expected to be in place
across the Hawaii domain through this week, with mainly zonal
surface flow with the main surface high centered well to the
north, and upper level ridging in place across the state. There
may be a weakening surface trough that approaches the state from
the east by next weekend, but it does not appear to be all that
impactful based on the latest model guidance.

The models suggest the typically favored windward terrain of the
larger Islands will have daily showers, with the trades out of the
ENE on most days. With the deepest moisture remaining well south
of the state, no major rainfall events are currently expected over
the next seven days.

Hamrick

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
901 PM EDT Mon Jul 1 2024
Day 1
Valid 01Z Tue Jul 02 2024 - 12Z Tue Jul 02 2024

...A MODERATE RISK OF EXCESSIVE RAINFALL IS IN EFFECT FOR PORTIONS
OF EASTERN NEBRASKA TO SOUTHWESTERN IOWA...

...Central/Northern Plains to Upper Midwest...

Convection has been growing upscale and will continue to do so
into the evening across the northern half of the Plains. The most
concerning area for flash flooding will be across parts of Nebraska
to Iowa, where the nocturnal LLJ of 50 knots will be maximized in
a moist environment fed by both Gulf moisture and Pacific moisture
rounding the mid-upper ridge, near a warm front. HRRR runs are
explicitly showing 1.5-2"/hour rates, which would exceed the FFG,
and other (albeit older) CAMs show higher total QPF. HREF
probabilities for exceeding 3 and 6 hr FFG are greater than 50
percent in some areas. Since the 18Z HREF is getting to be older
available model data at this point, focused the upgraded/embedded
Moderate Risk a bit on the southern side, where recent HRRR runs
are focusing the best potential for some training/backbuilding.
Refer to MPD 537 for more information on this area. Additional
convection farther north through the night could cause additional
flash flooding risks and the Slight Risk is maintained there in
parts of the Dakotas to Minnesota.

...Southeast...

A cold front slowly working its way south near the South
Carolina/Georgia coast is pooling moisture along it for some
ongoing convection. The risk level overall has dropped since this
afternoon, prompting removal of the Moderate Risk but maintained a
Slight for slow-moving storms. The Savannah, Georgia area is likely
the most vulnerable to additional localized flooding concerns.

...Southwest...

Monsoonal moisture with PWs over the 95th percentile/2-3 standard
deviations above normal in the Four Corners states is causing
ongoing convection that has prompted several Flash Flood Warnings.
Storms will persist further into the evening and a Marginal Risk
remains in place.

Tate

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
424 AM EDT Tue Jul 2 2024
Day 1
Valid 12Z Tue Jul 02 2024 - 12Z Wed Jul 03 2024

...THERE IS A SLIGHT RISK FROM PORTIONS OF THE UPPER MIDWEST TO THE
PLAINS...

...Upper Midwest through Central Great Plains...

Still on track for heavy rainfall over portions of Iowa and Missouri
as well as a small portion of neighboring states given plenty of
synoptic scale forcing and upper level jet support as well as
plenty of deep layered moisture. There still appears to be some
potential for training and backbuilding...so concern for flash
flooding is towards the high end within the Slight category. The
potential for cold pools helping to keep convection moving and the
fact that overlap with areas hard hit by previous heavy rainfall to
the north appears less than it was on Monday. We will continue to
watch for trends in subsequent high resolution model runs.

...Southeast...

A Marginal Risk is maintained over the Florida Panhandle and
southern GA in proximity of a slow moving cold front. Rainfall
still expected to be lower than what fell on Monday, but the
plentiful Gulf moisture allows for the potential for very high
rainfall rates and localized large rainfall amounts.

...Southwest...

Again maintained a Marginal over eastern AZ/western NM with a
suppressed Monsoonal flow day as troughing to the north shunts the
ridge axis farther east to the lower Miss Valley. Elevated moisture
is limited to the southern portions of those states and remnant
stratus from Monday night activity may further suppress Tuesday
activity.|

Bann

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
424 AM EDT Tue Jul 2 2024
Day 2
Valid 12Z Wed Jul 03 2024 - 12Z Thu Jul 04 2024

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE MIDWEST TO THE GREAT PLAINS...

...Midwest to Great Plains...

A cold front from a passing trough over the northern tier of states
stalls over KS/MO by Wednesday morning, providing renewed focus
for thunderstorm development from eastern KS through southern IL
with potential for heavy to excessive rainfall...with only minor
adjustments needed to the placement of the Slight Risk already in
place.

The frontal zone extends east over the rest of the Midwest to the
eastern Great Lakes where a Marginal Risk is maintained with some
areas of the Northeast trimmed with the 02/00Z QPF consensus being
farther west.

Over the northern Plains, the next trough axis enters the northern
High Plains Wednesday night with activity over the Dakotas
warranting a Marginal Risk.

...Southwest...

A trough axis from the next reinforcing wave allows anomalous
moisture over AZ/NM to spread northeast to the southern High Plains
on Wednesday which warrants maintenance of the Marginal Risk with
some trimming based on the 00Z consensus.

Bann

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
424 AM EDT Tue Jul 2 2024
Day 3
Valid 12Z Thu Jul 04 2024 - 12Z Fri Jul 05 2024

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE CENTRAL US...

...Upper Midwest to Mid Mississippi Valley...

Mid and upper level height falls across the upper midwest dropping
into a region with anomalously moisture rich environment should
result in increasing chances of showers and thunderstorms on
Thursday and Thursday night...with embedded shortwave energy and
divergence aloft from a digging upper jet focusing and supporting
areas of heavy rain and chances for excessive rainfall from intense
rainfall rates during the latter part of the outlook period.

...Mid-Mississippi Valley eastward...
Moisture should start to be transported from the Mid-Mississippi
Valley eastward across the Ohio/Tennessee Valleys into the Mid
Atlantic region as flow aloft responds to the digging trough over
the nations mid-section. Some guidance generates convection that
may challenge flash flood guidance. There was already a Marginal
Risk introduced and saw little reason to make more than minor
adjustments in placement.

Bann

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
257 AM EDT Tue Jul 2 2024


Heavy rain with embedded thunderstorms are likely to continue
across northern Wisconsin and into the Upper Peninsula of Michigan
going into Friday as the developing surface low tracks across the
region, and a Marginal Risk will remain there for the Day 4 period.
Farther south, a corridor of heavy showers and storms is likely
from northern Texas to the Tennessee River Valley, and a Marginal
Risk area is also valid here for Friday. This has trended more
southward compared to yesterday's forecast. Looking ahead to
Saturday, there is enough of a model signal to support a planned
Marginal Risk area for portions of the Mid-Atlantic, where some
slow moving thunderstorms are likely to develop in the vicinity of
a slow moving frontal boundary. Some of the outer rain bands of
Beryl could be approaching southern Texas by late Saturday and
into early Sunday, but generally not expected to be heavy enough by
that time to warrant any risk areas. This could change going into
Sunday, especially if the track trends farther north in later
forecast updates, so stay tuned!

It will continue to remain hot and humid across Texas and extending
eastward across the Deep South and into the Southeast for the end
of the week and into next weekend, with highs in the middle to
upper 90s and dewpoints well into the 70s. It will also be getting
very hot for the inland lower elevations of California and into the
Arizona Deserts with widespread 105-115 degree readings likely,
and locally higher for the normally warmer locations. Daily
temperatures records may be tied or broken in many cases. The heat
likely expands across inland portions of Washington, Oregon, and
much of the Intermountain West by the Sunday-Tuesday time period,
with 100+ degree highs likely for the lower valley locations.

Hamrick

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
257 AM EDT Tue Jul 2 2024


Heavy rain with embedded thunderstorms are likely to continue
across northern Wisconsin and into the Upper Peninsula of Michigan
going into Friday as the developing surface low tracks across the
region, and a Marginal Risk will remain there for the Day 4 period.
Farther south, a corridor of heavy showers and storms is likely
from northern Texas to the Tennessee River Valley, and a Marginal
Risk area is also valid here for Friday. This has trended more
southward compared to yesterday's forecast. Looking ahead to
Saturday, there is enough of a model signal to support a planned
Marginal Risk area for portions of the Mid-Atlantic, where some
slow moving thunderstorms are likely to develop in the vicinity of
a slow moving frontal boundary. Some of the outer rain bands of
Beryl could be approaching southern Texas by late Saturday and
into early Sunday, but generally not expected to be heavy enough by
that time to warrant any risk areas. This could change going into
Sunday, especially if the track trends farther north in later
forecast updates, so stay tuned!

It will continue to remain hot and humid across Texas and extending
eastward across the Deep South and into the Southeast for the end
of the week and into next weekend, with highs in the middle to
upper 90s and dewpoints well into the 70s. It will also be getting
very hot for the inland lower elevations of California and into the
Arizona Deserts with widespread 105-115 degree readings likely,
and locally higher for the normally warmer locations. Daily
temperatures records may be tied or broken in many cases. The heat
likely expands across inland portions of Washington, Oregon, and
much of the Intermountain West by the Sunday-Tuesday time period,
with 100+ degree highs likely for the lower valley locations.

Hamrick

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
1251 PM EDT Mon May 20 2024

Valid 00Z Tue May 21 2024 - 00Z Fri May 24 2024

...WPC Winter Weather Desk no longer routinely staffed this
summer...

Pending any significant winter weather, the WPC Winter Weather Desk
will not be staffed this summer. The desk will resume continuous
staffing starting in late September 2024.

Most of the winter products from WPC will continue to be produced,
including the Winter Storm Severity Index (WSSI), Probabilistic
Winter Storm Severity Index (WSSI-P), and the Probabilistic Winter
Precipitation Forecasts (PWPF).

WPC

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
257 AM EDT Tue Jul 2 2024

Valid 12Z Fri Jul 5 2024 - 12Z Tue Jul 9 2024

***Major heatwave expected for the lower elevations of California
and the Desert Southwest next week, and Beryl eventually headed
for the Western Gulf***

...Overview...

The main thing making weather headlines during this forecast period
will the intense and prolonged heatwave encompassing much of
California and extending into the lower elevations of the Desert
Southwest. Hot and humid conditions will also continue for much of
the southern states and extending to the East Coast. A low pressure
system is forecast to cross the Upper Midwest and bring a round of
heavy rain and storms to the Great Lakes on Friday, and additional
storms near the trailing frontal boundary across portions of the
Southern Plains and extending east to the Ohio Valley and the Mid-
Atlantic region. The track of Hurricane Beryl is expected to enter
the Bay of Campeche and the Western Gulf by Saturday with rainfall
chances increasing for portions of southern Texas by the weekend.


...Guidance/Predictability Assessment...

The 00Z model guidance suite indicates good overall synoptic scale
agreement across the Continental U.S. to close out the work week,
and better agreement on the massive upper ridge building over the
West Coast, potentially reaching 600dm. The guidance suggests this
ridge should slowly move east over the southern Intermountain West
by next Tuesday/Wednesday. Meanwhile, a general trough axis
situated over the north-central U.S. should be anchored in place by
another ridge axis over the western Atlantic Ocean. A general
deterministic model blend sufficed as a good starting point in the
forecast process for Friday/Saturday, and then increased the
ensemble means to about 40% by next Tuesday.

The latest forecast from the National Hurricane Center has
Hurricane Beryl reaching the Yucatan Peninsula around Friday
morning, and then emerging over the Bay of Campeche by Saturday,
followed by more of a northwestward turn. There has been a recent
trend in the guidance for a more northward track by the time it
enters the western Gulf, which could result in deteriorating
weather conditions for southern Texas. The trough over the Central
U.S. will be a big factor in determining the eventual track.
Beryl's
track will continue to be closely monitored over the next several
days, and the NHC has additional information pertaining to this.


...Weather/Hazards Highlights...

Heavy rain with embedded thunderstorms are likely to continue
across northern Wisconsin and into the Upper Peninsula of Michigan
going into Friday as the developing surface low tracks across the
region, and a Marginal Risk will remain there for the Day 4 period.
Farther south, a corridor of heavy showers and storms is likely
from northern Texas to the Tennessee River Valley, and a Marginal
Risk area is also valid here for Friday. This has trended more
southward compared to yesterday's forecast. Looking ahead to
Saturday, there is enough of a model signal to support a planned
Marginal Risk area for portions of the Mid-Atlantic, where some
slow moving thunderstorms are likely to develop in the vicinity of
a slow moving frontal boundary. Some of the outer rain bands of
Beryl could be approaching southern Texas by late Saturday and
into early Sunday, but generally not expected to be heavy enough by
that time to warrant any risk areas. This could change going into
Sunday, especially if the track trends farther north in later
forecast updates, so stay tuned!

It will continue to remain hot and humid across Texas and extending
eastward across the Deep South and into the Southeast for the end
of the week and into next weekend, with highs in the middle to
upper 90s and dewpoints well into the 70s. It will also be getting
very hot for the inland lower elevations of California and into the
Arizona Deserts with widespread 105-115 degree readings likely,
and locally higher for the normally warmer locations. Daily
temperatures records may be tied or broken in many cases. The heat
likely expands across inland portions of Washington, Oregon, and
much of the Intermountain West by the Sunday-Tuesday time period,
with 100+ degree highs likely for the lower valley locations.

Hamrick


Additional 3-7 Day Hazard information can be found on the WPC
medium
range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast (QPF), excessive rainfall
outlook (ERO), winter weather outlook (WWO) probabilities, heat
indices, and Key Messages can be accessed from:

https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw