FOUS30 KWBC 060800
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Sat Jun 6 2026

Day 1
Valid 12Z Sat Jun 06 2026 - 12Z Sun Jun 07 2026

...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
SOUTHERN PLAINS, OHIO VALLEY, UPPER TEXAS COAST, AND CENTRAL GULF COAST...

...Southern Plains...

A plume of deep tropical moisture will surge northward across the
Southern Plains on Saturday. The low level jet advecting this
moisture north will run into an area of enhanced lift due to a
nearby upper level shortwave, which will be lifting northeast to
rejoin the jet. The result will be a series of rounds of storms
moving north-northeast across portions of north Texas, eastern 
Oklahoma and western Arkansas. Highly efficient warm rain processes
will dominate due to the present of such abundant amounts of
moisture, with PWATs close to 2 inches. For eastern
Oklahoma/western Arkansas, the rain will persist for much of the
day in the form of training lines of storms. Back into Texas, the
threat will be mostly overnight tonight due to persistent storms
associated with an MCS that will drift east across far north Texas
and southern Oklahoma. An internal higher-end Slight was introduced
from southwest of the Metroplex through it, and continuing into
much of eastern Oklahoma and western Arkansas for the combination
of two areas of persistent heavy rain. Overall changes from
inherited were minimal.

...Ohio Valley...

A very-slow moving cold front drifting south across the
Midwest/Ohio Valley on Saturday will be the animus for multiple
rounds of storms which will track east-southeast from Indiana east
to the central Appalachians. A new Slight Risk area was introduced
with this update. In the upper levels, a shortwave may help the 
storms become stronger for the first part of the period before 
shifting off to the east. The front will form the leading nose of a
plume of deep Gulf moisture tracking northward up the Mississippi 
Valley. The front will "shear" the moisture eastward in a narrow 
corridor, along which the storms will form and move. Stronger and 
more persistent storms from Indiana to western Ohio will become 
somewhat less strong and less organized into the Mountains of 
western Pennsylvania and West Virginia, but those areas will have 
lower FFG thresholds, allowing the two areas to combine into one 
Slight Risk area for somewhat different reasons. Uplift along the
western face of the Appalachians may also locally enhance rainfall rates.

...Upper Texas Coast...

In coordination with HGX/Houston, TX forecast office, a Slight Risk
upgrade was introduced with this update. Extreme amounts of
moisture will be in place throughout the atmosphere of southeast
Texas Saturday afternoon. PWATs between 2 and 2.25 inches are 3
sigma above normal for this time of year, an impressive threshold
to meet for June. With peak heating this afternoon, scattered
showers and thunderstorms are expected to form, likely 20-50 miles
inland from the coast. Cold pools from Friday's storms and new ones
from the storms that form Saturday afternoon will likely drive new
storm development along the I-10 corridor from southwest of Houston
to the TX/LA border near Beaumont. With plenty of new moisture
streaming north off the Gulf, the storms will have no trouble
reforming and training over the same areas for the duration of the
long afternoon. Nightfall should end the storms in the area due to
lack of other forcing and the loss of instability. Friday's storms
have knocked down FFGs in this region significantly, and with good
capability of efficient warm rain processes, urban concerns in
Houston, and slow storm movement were all reasons contributing to  
the Slight Risk upgrade.

...Central Gulf Coast...

Few changes were needed to the Slight Risk area from New Orleans 
east to Pensacola. A strong front is in place across the eastern
Gulf, characterized by very dry air to its east, rather than any
significant temperature gradient. The dry air is 2 sigma below
normal over portions of central Florida...under 1 inch PWATs. 
Meanwhile to the west from Louisiana through Texas, an abnormally 
moist air mass will be streaming north to the west of the high 
pressure area characterized by the dry air. Over much of Louisiana,
PWATs will be over 2.25 inches or 3 sigma above normal. The front
makes up the gradient between these extremely contrasting air
masses. Through the day, the front will push east as the moist air
mass gradually gains ground. However, the front will be the forcing
along which numerous showers and thunderstorms pushing north out of
the Gulf will form along. The front will be slow to move, allowing
repeating rounds of storms to impact the central Gulf Coast. FFGs
are high, about 4 inches/hour, but the repeating rounds of storms
should rather quickly bring those numbers down, allowing for widely
scattered instances of flash flooding to develop where the rains
are most persistent by late afternoon. Nightfall should see a
decrease in shower and storm activity, ending the flooding threat.

Wegman


Day 2
Valid 12Z Sun Jun 07 2026 - 12Z Mon Jun 08 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR MUCH OF THE
MID-MISSISSIPPI VALLEY, OZARKS, AND THE WESTERN TENNESSEE VALLEY...

A pair of forcings will work cause renewed rounds of showers and
storms across much of the Mississippi Valley on Sunday into Sunday
night. A slow moving but still potent upper level low will track
northeastward up the Plains and into the Midwest by late Sunday
night. Meanwhile a strong front oriented north-south will allow for
shower and thunderstorm development further east across portions of
the South. For the Mid-Mississippi Valley and Ozarks, the shortwave
will be the primary forcing. Deep tropical moisture characterized
by PWATs on either side of 2 inches will advect northward up the
Mississippi Valley. The shortwave will provide the forcing for
storms to form, along with the topography of the Ozarks. Many of
these areas, especially from far eastern Oklahoma, northwestern
Arkansas, and southwest Missouri have seen repeated rounds of heavy
rain in recent days, so FFGs are lower in this area. Thus, a
higher-end Slight was introduced for this area depicting an even
greater threat for flash flooding, as the topography of the Ozarks
works to increase the severity of any flooding. FFGs are also lower
from northern Missouri into Iowa. Storms forming in these areas
will be closer to the nose of the low level jet, though the upper
level shortwave should still be the primary forcing.

The Slight Risk area was expanded north up the Mississippi Valley
into southern and eastern Iowa and western Illinois with this update.

For portions of the western Tennessee Valley, including western
Tennessee far northeastern Mississippi, and especially northern
Alabama, the aforementioned north-south oriented front will be the
primary forcing for the first half of the day. The front will more
rapidly retreat east across Georgia by Sunday night, leaving any
forcing to weak upper level shortwaves. Thus, most of the storms
will be during the afternoon and evening during peak heating and
when the front is closer. FFGs are lower across northern Alabama
from recent heavy rainfall, around 2.5 in/hour, which due to PWATs
occasionally over 2 inches, should be easily attainable by the
strongest storms expected Sunday afternoon. Thus, the Slight Risk
was expanded southeast for these reasons.

Wegman


Day 3
Valid 12Z Mon Jun 08 2026 - 12Z Tue Jun 09 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
MID-MISSISSIPPI, LOWER OHIO, AND WESTERN TENNESSEE VALLEYS...

On Monday, the excessive rainfall risk translates a bit further
north and east into the Mid-Mississippi, lower Ohio, and western
Tennessee Valleys. A strong front over the Great Lakes will retreat
northeastward as the plume of anomalously deep moisture from the
Gulf surges northeastward to replace the drier air mass in place
over the Northeast. A slow-moving negatively tilted trough will
also promote upper divergence and lift throughout the atmosphere
over the Slight Risk area throughout the period. PWATs around 2
inches will be 3 sigma above normal for this time of year across
the region, so many of the storms that form will consist of highly
efficient warm rain processes, which will promote heavy rainfall.
FFGs across the region will average around 2-2.5 inches, which will
be easily overcome by many of the strongest cells, so long as their
forward speed is kept in check. The Slight Risk area was nudged
west over more of southeastern Missouri with this update, adjusted
for expected heavy rainfall and likely lower FFGs in this region 
from the Day 2/Sunday period.

Wegman
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