895
FXUS02 KWBC 020657
PMDEPD

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










$$