Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Fri Aug 30 2024
Valid 12Z Fri Aug 30 2024 – 12Z Sun Sep 01 2024
…Widespread shower and thunderstorm chances from the Plains to East
Coast to start the holiday weekend, producing heavy rain and severe
weather...
…Heavy rain and scattered flash flooding possible along the Louisiana
and upper Texas Gulf Coasts…
…Record heat continues across the Ohio/Tennessee Valleys into the
Southern Appalachians today with relief on tap for the weekend…
…Much above average temperatures build across the Pacific Northwest,
northern Great Basin and into the northern Rockies…
A broad area of showers and thunderstorms is expected over central and
eastern portions of the country heading into the first half of the holiday
weekend ahead of an approaching cold front. Today (Friday), storm chances
will stretch from the Lower Great Lakes southwest through the Middle
Mississippi Valley and into the Southern Plains/Rockies. Plentiful
moisture and instability ahead of the front will lead to some more robust
thunderstorms and locally heavy rainfall, with some isolated flash
flooding possible. In addition, an accompanying upper-level trough
overhead will bring some higher winds over the Great Lakes, leading to
stronger shear and the potential for some severe weather. There is a
targeted Slight Risk (level 2/5) from the Storm Prediction Center over
portions of eastern Michigan mainly for the risk of damaging winds. On
Saturday, the front will progress further south and eastward into the Ohio
Valley and Northeast while slowing in progress and becoming nearly
stationary with southwestward extent into the Southern Plains. A broader
area of severe weather is expected over portions of the northern/central
Appalachians and Mid-Atlantic as the upper-level trough digs southward
over the region. Damaging winds will once again be the primary threat. In
addition, isolated flash flooding will remain possible, with the potential
that a higher threat may materialize given the slowing frontal
progression.
Further south, another more concentrated area of heavier rainfall is
expected to continue along portions of the western Louisiana and upper
Texas Gulf Coasts as an area of low pressure lingers in the vicinity.
Higher rain rates and repeated rounds of storms may lead to locally higher
rain totals of 2-4″+ over Friday and Saturday. A Slight Risk of Excessive
Rainfall (level 2/4) has been included for both days for the potential of
some scattered flash flooding. Daily thunderstorms are also forecast over
the central/southern Florida Peninsula.
One more day of excessive heat is forecast over the Ohio/Tennessee Valleys
and southern Appalachians today as temperatures soar once again into the
mid- to upper 90s. High humidity may bring head indices into the low 100s.
A few record-tying/breaking highs will also be possible. The approaching
cold front and increasing storm chances/cloud cover will finally bring
some relief on Saturday as highs drop into the 80s across the Middle
Mississippi and Lower Ohio Valleys, with upper 80s to low 90s for the
Upper Ohio and Tennessee Valleys. Elsewhere, highs will be particularly
mild north of the frontal boundary across the northern Mid-Atlantic and
New England, with 70s and even some upper 60s expected today. Temperatures
will warm up a few degrees as the boundary lifts northward as a warm front
on Saturday. Conditions will also be well below average over portions of
the Southern Plains to the northwest of the frontal boundary, with low to
mid-80s forecast. Areas ahead of the front from Texas into the Southeast
and the southern Mid-Atlantic will generally be in the upper 80s to low
90s.
In the wake of the departing trough to the east, an upper-level ridge over
the Pacific Coast will shift inland, helping to focus hot, much above
average temperatures over the northern tier of the West. Forecast highs on
Friday for the northern Great Basin and Pacific Northwest will range
between the low to mid-90s for most locations. Then, on Saturday, the heat
will intensify as well as expand into the northern Rockies, with many
highs in the mid- to upper 90s, 10-20 degrees above average. Heat
Advisories have been issued for much of the northern Great Basin given the
heightened risk of heat-related illnesses, and extra care should be taken
to seek shaded areas and remain hydrated this holiday weekend. Elsewhere
in the West, temperatures will generally be near or just above average,
with 60s and 70s along the coast, 80s to low 90s for the Great Basin,
mid-90s for the central California Valleys, and 100s in the Desert
Southwest. A few showers and thunderstorms will be possible along a
lingering frontal boundary through the central/southern Rockies and into
the Southwest.