Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
300 PM EDT Sun Jul 31 2022
Valid 12Z Wed Aug 03 2022 - 12Z Sun Aug 07 2022
...Heat wave to spread from the Plains to the East Coast this
week...
...Wet Monsoonal Pattern continues for the Southwest and Great
Basin...
...General Overview...
Hot upper ridging intensifies over the central U.S. and expands
over the East this week as convection rides underneath over the
South. Monsoonal flow into the Southwest/Great Basin/Rockies stays
active and re-intensifies late week. An active upper level pattern
will be in place across the northern tier states of our fine
country, with a lead trough and cold front crossing the Upper
Midwest/Great Lakes and Northeast mid-late week. Another trough is
now expected to settle over the Northwest mid-late week, with
energy ejecting downstream into the weekend.
...Guidance Evaluation/Predictability Assessment...
The WPC medium range product suite was primarily derived from a
composite blend of now well clustered mid-larger scale guidance of
the GFS/ECMWF/UKMET/Canadian and GEFS/NAEFS/ECMWF ensemble means
as well as WPC continuity and the National Blend of Models. This
bolsters forecast confidence to above average levels in these
features and the manual adjustment and blending processes tend to
mitigate lingering and mainly smaller scale system timing and
focus variances consistent with individual system predictability.
...Weather/Hazards Highlights...
Another heat wave is expected to make weather headlines this week
from the Plains to the East, with daytime highs running well into
the 90s and exceeding 100 degrees in some cases to threaten some
local records. Meanwhile, temperatures will likely be near to
slightly below normal across much of the western U.S. for most of
the forecast period. This also includes the Desert Southwest
where increased cloud cover and rainfall will keep temperatures in
check.
In terms of precipitation, there is a stronger model signal for a
corridor of heavy showers and storms ahead of the cold front
crossing the Great Lakes and Ohio Valley, and a Slight Risk area
of the experimental WPC medium range Excessive Rainfall Outlook
(ERO) is shown in the midweek Day 4 outlook from northern Illinois
to southern Michigan. There will still be plenty of monsoonal
moisture in place across the southwestern U.S., with enough
expected coverage of slow moving storms to merit another ERO
Slight Risk area on Day 5 by Thursday across much of southeastern
Arizona. Scattered to numerous showers and storms are also likely
for portions of the Gulf Coast region to close out the week.
Hamrick/Schichtel
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, experimental excessive rainfall
outlook, winter weather outlook probabilities and heat indices are
at:
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