Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Fri Jun 30 2023

Valid 12Z Fri Jun 30 2023 - 12Z Sun Jul 02 2023

...More severe thunderstorms and areas of heavy rain to track eastward
from the central Plains to the Ohio Valley for the next couple of days...

...Excessive Heat Warnings and Advisories across much of California into
the Desert Southwest as well as through the lower and mid-Mississippi
Valley...

...Air Quality alerts over parts of the Midwest, Great Lakes, central
Appalachians, Northeast, and Mid-Atlantic...

A wavy front will continue to be the focus for severe thunderstorms and
areas of heavy rain to track eastward from the central Plains to the Ohio
Valley for the next couple of days.  The heaviest and strongest storms are
expected to gradually shift farther east each day as a better-defined low
pressure wave reaches into the lower Great Lakes by Sunday morning. 
Thunderstorm complexes that develop along the front will likely contain
heavy downpours, hail, along with damaging wind gusts, with the best
chance of these to occur over the mid-Mississippi and Ohio Valleys later
on Saturday per the Storm Prediction Center.  The gradual eastward shift
of the severe weather is in response to upper-level impluses ejecting from
the western U.S. upper trough.  The impluses will begin to erode the upper
ridge responsible for the ongoing heat wave across the South and help
bringing in cooler air ever so slowly east across the central Plains.  The
hottest temperatures into the triple-digits are forecast to reach the
northern-most locations in Missouri today while more oppressive humidity
will continue farther south closer to the Gulf Coast. 

As the cooler air reaches into the central Plains through the next couple
of days, heat will begin to build further up the West Coast and then reach
into the northern Plains by Sunday.  Meanwhile, after a day of drier
weather across the Northeast, showers and thunderstorms from the Midwest
are forecast to reach into the central Appalachians today before slowly
edging into interior New England Saturday, and especially by Sunday
morning ahead of a cold front.

In addition to the current weather activity, Canadian wildfire smoke is
expected to continue impacting portions of the eastern U.S. over the next
few days. However, air quality is expected to improve in the short term as
a combination of thunderstorm activity and dispersion of smoke will
ultimately result in improving air quality conditions for much of the
country heading into the weekend.

Kong/Genz


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