Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Sat Jul 08 2023

Valid 12Z Sat Jul 08 2023 - 12Z Mon Jul 10 2023

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

...Locally heavy rainfall and flash flooding possible likely for the
Northeast on Sunday...

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

A slow-moving frontal boundary under energetic northwest flow aloft will
lead to additional rounds of severe weather and flash flooding over
portions of the Central/Southern Plains and Lower Mississippi Valley this
weekend. Rich moisture pooling along and to the south of the boundary will
lead to efficient downpours, and the continued tendency for storms to
cluster/grow upscale will lead to broad areal coverage of heavy rainfall
totals. Slight Risks of Excessive Rainfall (level 2/4) are in effect both
Saturday and Sunday, with wet soils from repeated rounds of organized
storms/rainfall the last few days increasing the risk for some scattered
flash flooding. Additionally, the moderately strong northwest flow aloft
over southerly winds at the surface will lead to sufficient deep-layer
shear to aid storm organization. A Slight Risk of severe weather (level
2/5) has been issued by the Storm Prediction Center for portions of the
Central/Southern Plains into the Lower Mississippi Valley Saturday, and
continued for the Lower Mississippi Valley Sunday, as the well-organized
convection may produce damaging winds, and perhaps some large hail.
Shortwave energy ejecting from a stalled upper-level low over
south-central Canada will help to drive additional frontal systems
southward through the Midwest/Plains, helping to keep temperatures
generally below average and bring additional precipitation chances to the
Upper Midwest on Sunday. Storms and general cloudiness will also
contribute to unseasonably cool summer temperatures, particularly for
portions of the Central/Southern High Plains where highs will be running
10-15 degrees below average. In general, highs will be running in the
mid-70s to low 80s. Temperatures will warm up for portions of the Northern
Plains Sunday in between fronts, with highs into the upper 80s and low
90s.

To the east, showers and storms are expected to develop again Saturday
along and to the east of a stalled frontal boundary draped along the
Appalachians. Some locally heavy rainfall will be possible from interior
New England south through the Mid-Atlantic and into the Carolinas. Lift
ahead of a developing upper-level shortwave in the mean flow as another
cold front from the west pushes eastward towards the coast will trigger
more numerous showers and thunderstorms on Sunday. Additional moisture
flowing northward ahead of the incoming system will once again promote
heavy downpours, and the tendency for storms to move northward parallel to
the incoming front will lead to the potential for repeated rounds of heavy
rainfall. A Slight Risk of Excessive Rainfall (level 2/4) is in effect for
portions of interior New England/the Northeast south into the Mid-Atlantic
where the highest potential for these conditions overlaps wet antecedent
conditions from rainfall this past week. Increasing winds ahead of the
advancing shortwave will provide enough deep-layer shear for a few
organized, severe storms stretching from the Mid-Atlantic south and
westward through the Carolinas and Southeast. The Storm Prediction center
has highlighted the region with a Slight Risk of severe weather for the
chance of damaging winds and perhaps some large hail.

To the east and south of the front, forecast highs Saturday will be in the
low to mid-80s for New England, upper 80s to low 90s for the Mid-Atlantic,
low to mid-90s for the Southeast into the Lower Mississippi Valley, and
mid- to upper 90s for eastern Texas. Highs will drop into the mid- to
upper 80s from the Mid-Atlantic southwest into the Tennessee Valley
influenced by rain/storms and frontal passage Sunday, with high only in
the 70s for portions of the interior Northeast west into the Upper Ohio
Valley and Lower Great Lakes. Highs will once again be in the mid-90s for
Florida. Of particular note is while these highs don't stand out as
significantly above average, they continue to be at or near
record-tying/breaking levels, with near record-tying/breaking overnight
warm lows as well.High temperatures will remain hot this weekend for
portions of west Texas and the Southwest situated under a stagnant
upper-level ridge aloft. Heat-related warnings and advisories remain in
effect for the region for high temperatures in the 100s, with low 110s for
portions of southern Arizona. The ridge will begin to shift/expand
westward late in the period, signaling increasing temperatures for
portions deeper into the desert Southwest and southern California.
Temperatures will also be running above average for the interior Pacific
Northwest, with some heat-related advisories in effect as highs climb into
the upper 90s. Temperatures will increase across the Great Basin Sunday as
the upper-level ridging expands northwestward, with highs ranging from the
mid-90s to low 100s.

Putnam


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