A stormy weather pattern throughout much of the south-central United States and Southeast is expected to continue through midweek as a frontal boundary lingers across the region.
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Plentiful atmospheric moisture content and instability will allow for developing thunderstorms near the quasi-stationary front each day between today and Wednesday, with the severe weather and heavy rainfall threats gradually shifting eastward with time.
For today, thunderstorms capable of containing intense downpours, damaging wind gusts, large hail, and a few tornadoes are most likely to impact a region extending from the southern Plains to the central Gulf Coast.
Very large hail is possible across central Texas, where the Storm Prediction Center has issued an Enhanced Risk (level 3/5) for severe weather.
By Tuesday and Wednesday upper-level forcing supports greater thunderstorm chances strung eastward along the frontal boundary towards the Southeast.
Here, scattered severe thunderstorms and daily rainfall amounts over 2" are forecast.
Where clusters of storms overlap, flash flooding will be a concern across low-lying and urban regions.
Farther west along this same frontal boundary, flash flooding and scattered thunderstorms are once again a possibility throughout the central High Plains today.
Since this region has experienced a very wet past few months, terrain will be more susceptible to flooding concerns where heavy rainfall occurs.
A Slight Risk (level 2/4) for Excessive Rainfall has been issued for an area extending from southeast Wyoming to western Oklahoma.
Some storms between southeast Colorado and the Oklahoma Panhandle could also be strong enough to contain large hail.
Elsewhere, a low pressure system deepening over the Great Lakes and attached cold front pushing through the Mid-Atlantic today will allow for isolated-to-scattered severe weather chances from eastern North Carolina to southern New Jersey.
Locally heavy rain is also possible from eastern Pennsylvania to central New York State, but should be mostly beneficial given the very dry month so far.
However, an isolated instance of flash flooding can't be ruled out should overlapping thunderstorms occur over urbanized areas.
This low pressure system will also produce scattered showers into New England and the Great Lakes through Wednesday.
Another round of unsettled weather is anticipated to enter the Ohio Valley and central Appalachians on Tuesday as the system finally makes its exit eastward.
The Intermountain West will also remain active with widely scattered showers and thunderstorms to the north of a disintegrating upper-level low.
Isolated flash flooding could impact sensitive terrain between the Sierra Nevada and northern Rockies.
A strong cold front pushing into the northern Great Basin Tuesday night will provide focus for potentially more organized convection over the northern High Plains on Wednesday.
Summer heat will continue to plague central and southern Texas through this week as widespread high temperatures reach into the upper 90s and low 100s.
When combined with humidity, heat indices are forecast to reach into the 110s across South Texas.
Above average temperatures are also anticipated over northern New England today, as well as the Northwest and north-central U.S. through midweek.
For these locations, highs are forecast to reach into the mid-to-upper 80s and low 90s.
Meanwhile, sustained below average temperatures are expected over the Southwest, central High Plains and Great Lakes. ■