450
FOUS30 KWBC 070813
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
413 AM EDT Sat Jun 7 2025

Day 1
Valid 12Z Sat Jun 07 2025 - 12Z Sun Jun 08 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS THE LOWER
ARKANSAS VALLEY, LOWER MISSISSIPPI VALLEY INTO THE LOWER TENNESSEE
VALLEY AND OVER CENTRAL NEW ENGLAND...

The next round of shortwave energy pushing into the Central to
Southern Plains early Saturday morning will progress into the Lower
MO Valley/Mid MS Valley/OH Valley region during the day Saturday.
This upper trof will become more negatively tilted with a well
defined area of upper difluence pushing eastward. Convection
likely to enhance in this broad upper difluence region where PW
values will remain 1.5 to 2+ standard deviations above the mean
across a large region from the OH Valley, south into the Mid to
Lower MS Valley and TN Valley. Across the northern portions of the
precipitation area from the Lower OH/Mid MS Valley region,
consensus is for the next round of precip to fall just to the north
of where the heavy amounts fell over the past 24 hours. This
should reduce the risk of runoff issues. Given that there is not
expected to be a significant overlap of day 1 precip with the
previous 24 hours observed precip, the risk level was kept as
marginal here.

Farther to the south, not a lot of changes made to the broad slight
risk area from the Lower AR, Lower MS Valley, east into northern MS
and northern AL. The slight risk area continues to fit well with
the axis of high HREF neighborhood probabilities for 1 and 2"+
amounts this period. There may be more than 1 round of convection
to move across this region. The initial, early day 1 from the
convection currently enhancing over the Southern Plains, followed
by a second round late Saturday afternoon along the surface frontal
boundary. With each round of convection, hourly rainfall totals of
.50-1"+ possible.

...Southeast NY State into New England...
Another round of convection likely day 1 along the frontal
boundary pushing through the northeast as a sharpening northern
stream trof pushes across the Northeast. A slight risk area was
introduced from the previous issuance to correspond to where there
is an overlap between heavy precip from Friday afternoon and
expected additional heavy precip between 1500 UTC Sat and 0000 UTC
Sun. This corresponds to an area from north central MA, across
southern NH into southwest ME. In this region the latest HREF
probabilities for .50 and 1"+ hourly amounts are fairly high and
where soils have become increasingly saturated.

Oravec


Day 2
Valid 12Z Sun Jun 08 2025 - 12Z Mon Jun 09 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS NORTHERN
TEXAS AND SOUTHERN OKLAHOMA...

...Southern Plains to the Southeast...
The latest guidance remains consistent in showing additional
shortwave energy pushing east southeastward late Sunday
afternoon/evening from the lee of the Central to Southern Rockies
into the Southern Plains in the northwest flow on the south side
of a stronger upper level low centered over the north-central
United States. This will again re-strengthen the low level flow
into the west to east oriented front forecast to remain across the
Southern Plains, supporting another round of organized convection
along the front. There continues to be fairly good agreement on
the potential for an axes of heavy precip day 2, resulting in good
continuity with the slight risk area with only some small changes
to reflect the latest forecasts. This next round of organized
convection will likely be fairly progressive, similar to what
occurred farther to the north Thursday night into early Friday and
Friday night into early Saturday. Still, there is likelihood of
widespread rainfall amounts of 1-2" with localized amounts up to
4". Soils are not as saturated as areas farther north, but
localized runoff issues are still likely.

...Central Appalachians into the Mid-Atlantic...
The negatively tilted shortwave coming out of the OH Valley late
day 1 will push across the Central Appalachians into the Mid-
Atlantic day 2. There is a fair amount of spread with model qpfs,
but a signal for the potential for locally heavy rains in the
continued well defined area of upper difluence ahead of these
height falls in an axis of above average PW values...1.5 to 2+
standard deviations above the mean. There were only some minor
changes made to the previous marginal risk across the Central
Appalachians into the Mid- Atlantic, continuing to center it across
areas that have lower ffg values.


Oravec


Day 3
Valid 12Z Mon Jun 09 2025 - 12Z Tue Jun 10 2025

...THERE IS A MARGINAL OF EXCESSIVE RAINFALL ACROSS THE SOUTHERN
PLAINS, LOWER MISSISSIPPI VALLEY, NORTHEAST THROUGH THE TENNESSEE
VALLEY, UPPER OHIO VALLEY AND INTO THE EASTERN GREAT LAKES...

There is good agreement in the latest guidance with the slow
eastward push of the closed low through the Upper Lakes day 3 and
the broad upper troffing extending south of this center through the
MS and OH Valleys. A broad region of above average PW values will
continue to stretch across the southern tier from the Southern
Plains, east across the Lower MS Valley and into the Southeast
along and ahead of the lead west to east oriented front. Another
axis of above average PW values will push northeastward across the
TN and OH Valleys into the Lower Lakes ahead of a secondary front
rotating through the cyclonic flow on the southeast side of the
strong closed low over the Upper Lakes. Along each frontal
boundary, widespread moderate to locally heavy precip totals are
likely. Model agreement, however, is not great with placement of
maximum amounts, leading to overall low confidence in where
anything but a marginal risk could be drawn. Overall, the previous
broad marginal risk area fits well with the latest model qpf
spread, with no significant changes made to previous outlook for
the new day 3 outlook.


Oravec

Day 1 threat area: https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt
Day 2 threat area: https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt
Day 3 threat area: https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt