Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Sun Jul 09 2023

Valid 12Z Sun Jul 09 2023 - 12Z Tue Jul 11 2023

...Heavy rain and instances of flash flooding likely across parts of the
Northeast on Sunday, with the threat lingering across New England on
Monday...

...Additional rounds of severe weather and flash flooding persist across
the Central/Southern Plains and Lower Mississippi Valley through this
weekend...

...Anomalously hot weather continues for portions of the Southwest, West
Texas, interior Pacific Northwest, and Florida Peninsula...

A consolidating frontal boundary currently stretching from the Northeast
southwest through the Ohio/Tennessee Valleys and into the Southern Plains
that has led to days of active weather will continue to be the focus for
storm development for the next couple of days. A couple days of
widespread, very heavy rainfall and the risk for flash flooding is in
store for portions of the Northeast. Upper-level energy rotating around
the base of a deep upper-level low over south-central Canada as well as a
slow moving frontal boundary approaching from the west will help to
trigger numerous showers and storms. A steady stream of anomalously high
moisture continues to flow into the region and will help to fuel very
heavy downpours with efficient, high rain rates. The mean southerly flow
east of the front will also lead to the tendency for storms to repeatedly
move over the same locations, leading to the potential for several inches
of rain each day. A Moderate Risk of Excessive Rainfall (level 3/4) is in
effect Sunday from interior New England south-southwest into the
Mid-Atlantic where the highest probabilities for significant heavy
rainfall overlap wet antecedent conditions, leading to the risk for
scattered to widespread instances of flash flooding. A Moderate Risk is
also in effect Monday for interior New England as conditions remained
primed for heavy rainfall ahead of the slowly eastward moving front. A bit
more unstable atmosphere residing over the Mid-Atlantic and Carolinas may
also lead to some more organized storms capable producing gusty winds,
with a Slight Risk of severe weather (level 2/5) in place from the Storm
Prediction Center. The presence of widespread storms as well as the
frontal boundary moving through will lead to cooler temperatures broadly
across the Northeast, with 70s for the Upper Ohio Valley, Lower Great
Lakes, and portions of New England and 80s elsewhere.

Storm chances will be much lower Sunday for the Central/Southern Plains
after remaining storms overnight Saturday clear out Sunday morning, with
storm chances remaining ahead of the front in the Lower Mississippi Valley
and Southeast. A Slight Risk of Excessive Rainfall (level 2/4) stretches
from the Southern Plains southeast into the Lower Mississippi Valley
following the likely track of organized convection/redevelopment
persisting through the day with locally heavy rainfall possible. A few of
the more robust, organized storms redeveloping along the frontal boundary
may also produce some gusty winds, with a Slight Risk of severe weather in
effect. Following the departure of storms early Sunday, atmospheric
conditions will rebound a bit more Monday ahead of another cold front
pushing southward into the Plains/Midwest, with increasing precipiation
chances for portions of the Upper Midwest and Central Plains as well as
the Northern High Plains and Rockies Monday. A Slight Risk of severe
weather is in place over portions of the Central Plains where storms may
produce gusty winds and large hail. High temperatures overall will remain
well below average Sunday across portions of the Central/Southern Plains
under the influence of the southern frontal boundary and
clouds/precipitation, hovering in the upper 70s to low 80s. Conditions
will return closer to average Monday with mid- to upper 80s expected.
Locations from the Northern Plains east into the Upper Midwest and Great
Lakes region will see a warm up ahead of the incoming cold front, with
highs in the mid-80s to low 90s. Temperatures will drop into the 70s for
locations behind the front in the Northern Plains/Upper Midwest Tuesday.

Meanwhile, to the south and west of the frontal boundary, conditions will
remain hot from Florida to Texas and the Southwest as well as the interior
Pacific Northwest. Highs in the mid-90s continue to be close to
record-tying/breaking high temperatures for the Florida Peninsula, and a
Heat Advisory is in effect for South Florida where these hot temperatures
combined with high humidity will lead to heat indices in the 105-109
degree range. Hot temperatures over portions of west Texas and the
Southwest have begun to broaden in coverage as an upper-level high builds
in aloft with heat related advisories stretching from east Texas west
through the Desert Southwest. High temperatures in the upper 90s to 100
for east Texas combined with high humidity will lead to heat indices in
the 105-110 degree range over the next couple of days. To the west,
humidity wont be as high, but temperatures will be in the 100s, with some
110s in the Desert Southwest. Mean upper-level ridging northward through
the Great Basin and into the interior Pacific Northwest will lead to one
more day of much above average temperatures for the interior Pacific
Northwest. Highs will be in the upper 90s for many locations before an
upper-level wave approaching Monday helps to drop temperatures down into
the 80s and much closer to average. Temperatures will generally be above
average across portions of the Rockies and Great Basin, with highs into
the 90s. The noted upper-level wave over the Pacific Northwest as well as
a second upper-wave off the coast of California will keep temperatures
much cooler along the West Coast, with highs in the 60s for the immediate
coast and 70s to low 80s for inland locations. 

Putnam


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