Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
355 AM EDT Fri Jun 09 2023

Valid 12Z Fri Jun 09 2023 - 12Z Sun Jun 11 2023

...Heavy rain likely to produce additional instances of flash flooding
across Montana and the northern High Plains today...

...Severe weather threat increases across the Southern Plains and Lower
Mississippi Valley on Saturday...

...Air Quality Alerts due to Canadian wildfire smoke remain in effect over
parts of the Great Lakes/Ohio Valley to the Northeast and Mid-Atlantic...

Additional chances for heavy rain are likely to continue along an axis of
anomalous atmospheric moisture content extending from the northern Great
Basin to the northern Plains today, which is likely to lead to areas of
flash flooding. Saturated soils within the area combined with the
potential for a few additional inches of rainfall have prompted a Moderate
Risk (level 3/4) of Excessive Rainfall for parts of north-central Montana,
where several impacts associated with flooding are possible. Meanwhile,
developing thunderstorms are also likely along a quasi-stationary front
extending from the northern Plains to the Gulf Coast (draping around a
high pressure system stretched from the Midwest to the Tennessee Valley).
Locally heavy rain and isolated severe thunderstorms are possible along
the aforementioned front and to the south throughout the southern Plains.

By Saturday, a dry line located across western Texas combined with an
upper-level shortwave ejecting out of northwestern Mexico is expected to
spark clusters of thunderstorms that could contain large hail, damaging
wind gusts, and a few tornadoes as they progress from the southern Plains
to the Lower Mississippi Valley. The Storm Prediction Center has issued an
Enhanced Risk (level 3/5) of severe weather across northeast Texas and
adjacent sections of southeast Oklahoma, southwest Arkansas, and northeast
Louisiana. Locally heavy rain is also possible across the same region.
Additionally, isolated flash flooding is possible along the lingering
frontal boundary on Saturday as it extends from the Mid-Mississippi Valley
to the northern High Plains. As a consolidating area of low pressure
develops and progresses across the Ohio Valley on Sunday, areas of heavy
rain are possible along a lifting warm front between the Ohio and
Tennessee valleys. While the southerly flow increases atmospheric moisture
content allowing for the heavy rainfall potential, it will also allow for
much of the lingering wildfire smoke in the eastern U.S. to finally
subside.

However, leading up to the beginning of the weekend near-surface wildfire
smoke associated with Canadian fires is expected to continue plaguing
regions from the Great Lakes to the Mid-Atlantic with reduced air quality.
Northwesterly flow around a low pressure system over the Northeast will
continue the flow of smoke over the region, but should relax and
eventually shift to more of a westerly direction on Saturday. Pockets of
denser smoke could significantly reduce air quality and lead to lowering
visibility, with a wider region of light to moderate smoke leading to an
opaque sky and orange sunsets/sunrises. Air Quality Alerts remain in
effect from Michigan and Indiana to the northern Mid-Atlantic.

Temperatures throughout Lower 48 into this weekend are expected to feature
only a few regions with elevated summertime heat. Above average
temperatures are forecast throughout the Great Plains today before the
warm weather shifts to the southern Plains, Mid-Atlantic, and Northwest by
Sunday. Highs into the 80s and 90s are anticipated, with upper-90s and low
100s found throughout central and southern Texas.

Snell


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