Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
857 PM EDT Sat Jun 14 2025
Day 1
Valid 01Z Sun Jun 15 2025 - 12Z Sun Jun 15 2025
...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
OKLAHOMA AND THE MID ATLANTIC...
...Mid-Atlantic...
Convection moving southeast along a stationary front will result
in isolated to scattered flash flooding this evening across
portions of northern and eastern VA. Given the location of the
front and instability gradient it appears that the heaviest
rainfall rates will remain in VA, and thus we were able to take DC
and MD out of the Slight risk. High PWs and slow cell
motions/mergers near the front will allow for high rainfall rates
and isolated amounts exceeding 3" across portions of northern and
eastern VA.
...Oklahoma...
At least some flash flooding appears likely overnight into early
Sunday across portions of OK. In the mid levels we have a well
defined shortwave across KS, which will slowly drift southward into
OK tonight. To the south of this feature increasing low level
moisture transport/convergence will interact with a highly unstable
airmass. Convection will expand in coverage by later this evening,
and activity should initially be slow moving and exhibit
backbuilding characteristics. This will allow for areas of
excessive rainfall, with recent HRRR and RRFS runs depicting a
swath of 3-5" of rainfall, and both the 18z HREF and REFS showing
over a 40% chance of locally exceeding 5". By later tonight
convection will grow upscale and likely develop a stronger cold
pool resulting in a southward acceleration of convection. High
rainfall rates could still result in a localized flash flood threat
after this faster southward propagation occurs...but the coverage
and magnitude of the threat should be lower by then. Thus the
greater risk is this evening into tonight when convection should
be slower moving and backbuilding...and do consider this a higher
end Slight risk centered over central OK. Scattered flash flooding
is probable, some of which could be locally significant.
...Upper Midwest...
A Marginal risk was maintained across portions of far southeast SD
into IA. Seeing a recent expansion of slow moving convection near
a stationary front which could result in localized flash flooding
through the evening hours.
...Central Montana...
Convection over portions of central and eastern MT will continue
to pose an isolated flash flood risk into the overnight hours.
Recent HRRR runs are likely under doing rainfall amounts over this
area. Recent RRFS runs may be overdone, but likely do have a
better handle on the repeat nature of convection that should
continue into tonight. Impressive CAPE/Shear profiles will
continue to support convective clusters and supercells, and with
PWs over 1", heavy rainfall rates will be likely. Localized
rainfall upwards of 2-3" is possible through the overnight hours.
Chenard
Day 1 threat area:
www.wpc.ncep.noaa.gov/qpf/94epoints.txt
Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
857 PM EDT Sat Jun 14 2025
Day 2
Valid 12Z Sun Jun 15 2025 - 12Z Mon Jun 16 2025
...A SLIGHT RISK OF EXCESSIVE RAINFALL EXISTS FOR PORTIONS OF THE
MID ATLANTIC, SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY...
...Mid-Atlantic and Central Appalachians...
20Z Update: The previous SLGT risk remains favorable as the threat
for flash flooding, some locally significant are forecast across
portions of the Mid Atlantic and Central Appalachians Sunday. The
area of focus will reside around the stationary front that will
bisect the southern half of VA up through eastern WV, arcing back
into Western PA as southwesterly flow remains steadfast west of the
terrain in WV/PA through at least 18z. A corridor of elevated
theta_E will remain situated over Western PA as far north as Butler
county with a deep pool of moisture located along and south of the
front. Shortwave trough that has slowly trudged eastward through
the Central part of the CONUS will finally pick up forward speed
and shift eastward through the Central Apps and Mid Atlantic by the
afternoon hrs leading to increased large scale forcing over the
aforementioned area. General instability coupled with the ascent
pattern will lead to favorable conditions for scattered to
widespread convective activity with mean cell motions moving slowly
east and southeast through the course of the afternoon and
evening. A very robust signal within the 12z HREF neighborhood prob
fields indicate a likelihood of >3" (60-90%) of rainfall in the
strongest convective cores with a modest signal for >5" located
over the Appalachian front in WV (20-40%) and across the VA
Tidewater into the Richmond metro (40-60%). These signals are
aligned with a locally significant threat for excessive rainfall,
especially in these particular zones due to sensitivity concerns
from either complex terrain (Appalachians) or urbanization factors
(Southern VA and the Tidewater). Hourly rainfall rates between
2-3"/hr are likely in the heaviest rainfall with instantaneous
rates upwards of 5"/hr plausible across Southeast VA considering
the available instability >1500 J/kg and PWATs approaching +2
deviations within a well-positioned front that should enhance local
convergence pattern.
The SLGT risk inherited was maintained in the previous location,
but was expanded to the northwest to include more of Northern WV,
Western MD, and Western PA given the signals within the latest HREF
and the anomalous environment in place with the front nearby. There
is a potential for an upgrade across parts of Eastern WV into the
Tidewater where the highest probability of >3" is located,
overlapping with what will likely be already saturated grounds
after the activity yesterday and later this evening. We will be
monitoring the setup closely over the next 12-24 hrs.
Kleebauer
...Northern Plains into the Midwest and Mid-South...
20Z Update: The multi-MCS threat remains firm within the latest
deterministic with agreement among the ensembles for a dual QPF
maxima situated across both the Northern Plains/Upper Midwest, as
well as portions of the Southern Plains into the Lower Mississippi
Valley. The more robust signal for heavy rainfall is situated
across Southeast KS down through Eastern OK into AR thanks to MCS
propagation into the area on the back-end of D1 into the D2 period.
HREF blended mean QPF indicated an areal average between 1-2" with
the CAMs individual outputs putting down as much as 2-4" with the
morning complex across the areas above. Remnant MCV concerns will
enhance a redevelopment phase of the regional convective threat
over the Lower Mississippi Valley with some of the hi-res windows
indicating another 2-4" local maxima occurring the second half of
the forecast cycle. In this case, there would be sufficient totals
stemming from likely back to back to back occurrences of heavy
rainfall from D1 through D2 leading to likely flash flood concerns.
In this case, there was enough of a signal to warrant an expansion
of the SLGT to cover for the threat across OK and AR with the
greatest threat likely over the western Ozarks down into Central
AR.
Convective complex over the Northern Plains will likely be more on
the progressive side compared to its southern counter-part leading
to a capped higher end potential. Still, some of the heavier rain
forecast would overlap with areas that have been affected, or will
be affected by previous convective episodes leading to saturated
soils and a higher chance of localized impacts. The threat remains
within the MRGL risk threshold considering the signals and relevant
probs within the latest CAMs. A targeted upgrade is plausible if
the signal becomes stronger in later updates.
Kleebauer
..Previous Discussion..
A building upper ridge situated over the southern Rockies will tend
to result in northwest flow aloft across the northern Plains to the
ArkLaTex region. Multiple convective complexes are likely to
develop on the eastern periphery of this upper ridge, and
convective development will depend on whether a low-mid level cap
can be eroded, and this is more likely to happen across eastern
portions of Kansas/Oklahoma/Texas. The latest model guidance is
converging more on a concentrated area of enhanced rainfall across
portions of southwestern Missouri and northwestern Arkansas and
adjacent portions of Kansas and Oklahoma, where an organized MCS is
more likely to develop. Therefore, a Slight Risk area has been
introduced for this region.
Hamrick
Day 2 threat area:
www.wpc.ncep.noaa.gov/qpf/98epoints.txt
Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
857 PM EDT Sat Jun 14 2025
Day 3
Valid 12Z Mon Jun 16 2025 - 12Z Tue Jun 17 2025
...A MARGINAL RISK OF EXCESSIVE RAINFALL IS VALID FOR PORTIONS OF
THE UPPER MIDWEST, MID-SOUTH, AND THE MID-ATLANTIC...
20z Update: Consensus for locally heavy rainfall across portions of
the Northern tier of the CONUS remains favorable across a broad
area extending through the Dakotas, Nebraska, and the Upper Midwest
on Monday. The good news in the setup is the current evolution
would favor the heaviest rain across the Nebraska Sandhills, an
area much less prone to flash flooding due to the soil composition
which would necessitate extreme rainfall rates (>4"/hr) and has a
history of limited flash flooding due to the very low runoff
capabilities. So long as this consensus remains, it is unlikely an
upgrade would be necessary for the region so will be monitoring
closely as a northern or southern shift in the maxima would offer a
chance for a targeted upgrade. Heavy rain threat over the Northern
tier of ND and MN remains fairly isolated at this juncture and
will take a more robust signal to induce an upgrade. These areas
are typically harder to flood and already exhibit relatively high
FFG's for the 1/3/6 hr indices, so the threat will likely be of the
isolated variety, but will monitor the trends closely as we move
into CAMs range.
Across the Mid-Mississippi Valley, flash flood threat will likely
be tied to yet another MCS moving across the area comprised of the
Ozarks, Southeast MO into the western Ohio Valley. Some of these
areas will have fairly compromised soils given the daily occurrence
of heavy rain the periods prior, so will have to assess the
expected forward propagation of any complex closely to see if an
upgrade is warranted. Considering the trickiness of narrowing down
specifics for these convectively driven complexes, decided to
maintain general continuity for the MRGL risk, but expanded based
on ensemble QPF depiction with a slightly more robust output
compared to previous iterations.
The front across the Mid Atlantic will sink further south and pivot
away from the areas that will have received significant rainfall
the periods prior. The area with greatest overall potential is
along the Appalachian front in WV where the signal for another
round of at least isolated thunderstorm activity could very well
offer another flash flood concern. The threat is highest over NC
where the frontal positioning would be aligned as such that some of
the activity that develops on Monday could provide elements of
training within a well favored environment for heavy rain
prospects. Some of the deterministic is already pushing areal
averages of 2-3" across Central and Eastern NC, a signal that is
favorable to at least a MRGL threat of flash flooding over the
urban corridor. Pending trends within CAMs and the positioning of
the front, an upgrade is certainly plausible for both eastern WV
down through the NC Piedmont and points east.
Kleebauer
..Previous Discussion(s)..
...Mid-Atlantic region...
Overall, an improvement compared to what is expected over the
weekend, but there should still be enough moisture in the general
vicinity of a stalled stationary boundary over southern Virginia
and North Carolina to produce scattered storms with heavy rainfall.
Although the magnitude of rainfall expected on Monday is not
impressive, the very saturated ground by this time will be an
aggravating factor in terms of flooding potential, and therefore a
Marginal Risk area is valid from central West Virginia to the Outer
Banks of North Carolina.
...Mid-South...
The latest model guidance is honing in on a potential MCS that
could develop across portions of eastern Arkansas into western
Tennessee on Monday, and perhaps extending into portions of
southern Missouri and western Kentucky where the potential exists
for 1 to locally 2 inches of rainfall. A Marginal Risk area is
valid here since much of this rain would likely happen over a two
hour time period.
...Dakotas to the western Great Lakes...
A surface low over South Dakota with broad warm air advection ahead
of it will fuel the development of additional scattered showers and
storms on Monday. The model guidance remains varied in regards to
placement of QPF maxima, so a broad Marginal Risk is valid.
Hamrick
Day 3 threat area:
www.wpc.ncep.noaa.gov/qpf/99epoints.txt
Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
300 PM EDT Sat Jun 14 2025
Overall, it generally still remains the case that highly unsettled
weather will remain in the forecast across much of the
central/eastern U.S. through at least the middle of next week as
numerous embedded impulses in the upper- levels override frontal
boundaries with seasonable moisture in place. Uncertainty remains
with the specific day-to-day details given the short-wave energies,
frontal placement, and likely mesoscale boundaries from prior
days' storms driving new development each day. However, a more
focused corridor is apparent across the central/northern Plains
into the Upper Midwest with daily strong to severe thunderstorm
chances along a couple frontal boundaries. On day 4, Tuesday, QPF
in the guidance shows the potential for locally heavy, multi-inch
rainfall totals with widespread/potentially organized convection,
and a Slight Risk ERO is in place across portions of the Middle
Missouri Valley into the Upper-mid Mississippi Valley. This region
will have also experienced several days of rainfall prior to the
day 4 period, so antecedent conditions should remain wet. Some
additional areal adjustments may be necessary, particularly on the
southern end. Then, on day 5, Wednesday, the focus should shift a
bit eastward from the Upper Mississippi Valley into the Great Lakes
region and a Marginal Risk ERO remains. QPF in the model guidance
and a continued favorable pattern for organized convective
development suggest that a localized higher threat is possible, but
greater uncertainty in the location/areal coverage of this threat
as well as less sensitive antecedent conditions compared to the
prior day preclude higher probabilities at this time. In addition
to heavy rainfall/flash flooding, the Storm Prediction Center has
also highlighted portions of the Central Plains on Tuesday and the
Upper Mississippi Valley Wednesday for a severe weather risk as
seasonably strong instability and sufficient shear will bring the
threat for large hail and damaging winds, particularly with any
organized convective systems. Expect the focus for storms to shift
south and eastward Thursday- Saturday with eastward movement of
upper- troughing/associated surface frontal boundaries and upper-
level ridging beginning to build in over the central U.S, though
some additional shortwave energy could bring renewed precipitation
chances to the Midwest. A signal also remains for an enhanced
tropical moisture feed from the Gulf to northeast Mexico and South
Texas/West Gulf Coast next weekend to monitor for signs of system
development out from the Bay of Campeche/vicinity with the
potential for heavy rainfall. The approach of an upper-low/Pacific
system looks to bring some increasing precipitation chances to the
Pacific Northwest and over the West late next week/weekend.
Expect above average temperatures across the Intermountain West
and adjacent portions of the Plains and Southwest to generally
persist through next week as an amplifying pattern will support
broadening upper-ridging following the passage of an upper-wave
earlier in the week. Some more locally intense heat will continue
across portions of the Southwest into the southern High Plains/west
Texas through at least Tuesday as highs rise into the low to
mid-100s. Summer- like temperatures/muggy conditions will expand
from the Plains east through the Mississippi/Ohio Valleys and into
the Southeast/Mid- Atlantic ahead of an upper-wave/cold front. The
most intense heat will likely focus along the Gulf Coast, the Lower
Mississippi Valley, and along the Eastern Seaboard north through
the Carolinas and into the southern Mid- Atlantic, with heat
indices greater than 105 expected. The cold front passage may bring
some relatively more comfortable conditions from the Ohio Valley
east into Carolinas/Mid-Atlantic late next week/weekend. Highs will
begin to trend relatively cooler and below average across portions
of the Northwest and possibly further south along the West Coast
by late next week/weekend as an upper-low from the northeast
Pacific begins to overspread the region.
Putnam
Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
300 PM EDT Sat Jun 14 2025
Overall, it generally still remains the case that highly unsettled
weather will remain in the forecast across much of the
central/eastern U.S. through at least the middle of next week as
numerous embedded impulses in the upper- levels override frontal
boundaries with seasonable moisture in place. Uncertainty remains
with the specific day-to-day details given the short-wave energies,
frontal placement, and likely mesoscale boundaries from prior
days' storms driving new development each day. However, a more
focused corridor is apparent across the central/northern Plains
into the Upper Midwest with daily strong to severe thunderstorm
chances along a couple frontal boundaries. On day 4, Tuesday, QPF
in the guidance shows the potential for locally heavy, multi-inch
rainfall totals with widespread/potentially organized convection,
and a Slight Risk ERO is in place across portions of the Middle
Missouri Valley into the Upper-mid Mississippi Valley. This region
will have also experienced several days of rainfall prior to the
day 4 period, so antecedent conditions should remain wet. Some
additional areal adjustments may be necessary, particularly on the
southern end. Then, on day 5, Wednesday, the focus should shift a
bit eastward from the Upper Mississippi Valley into the Great Lakes
region and a Marginal Risk ERO remains. QPF in the model guidance
and a continued favorable pattern for organized convective
development suggest that a localized higher threat is possible, but
greater uncertainty in the location/areal coverage of this threat
as well as less sensitive antecedent conditions compared to the
prior day preclude higher probabilities at this time. In addition
to heavy rainfall/flash flooding, the Storm Prediction Center has
also highlighted portions of the Central Plains on Tuesday and the
Upper Mississippi Valley Wednesday for a severe weather risk as
seasonably strong instability and sufficient shear will bring the
threat for large hail and damaging winds, particularly with any
organized convective systems. Expect the focus for storms to shift
south and eastward Thursday- Saturday with eastward movement of
upper- troughing/associated surface frontal boundaries and upper-
level ridging beginning to build in over the central U.S, though
some additional shortwave energy could bring renewed precipitation
chances to the Midwest. A signal also remains for an enhanced
tropical moisture feed from the Gulf to northeast Mexico and South
Texas/West Gulf Coast next weekend to monitor for signs of system
development out from the Bay of Campeche/vicinity with the
potential for heavy rainfall. The approach of an upper-low/Pacific
system looks to bring some increasing precipitation chances to the
Pacific Northwest and over the West late next week/weekend.
Expect above average temperatures across the Intermountain West
and adjacent portions of the Plains and Southwest to generally
persist through next week as an amplifying pattern will support
broadening upper-ridging following the passage of an upper-wave
earlier in the week. Some more locally intense heat will continue
across portions of the Southwest into the southern High Plains/west
Texas through at least Tuesday as highs rise into the low to
mid-100s. Summer- like temperatures/muggy conditions will expand
from the Plains east through the Mississippi/Ohio Valleys and into
the Southeast/Mid- Atlantic ahead of an upper-wave/cold front. The
most intense heat will likely focus along the Gulf Coast, the Lower
Mississippi Valley, and along the Eastern Seaboard north through
the Carolinas and into the southern Mid- Atlantic, with heat
indices greater than 105 expected. The cold front passage may bring
some relatively more comfortable conditions from the Ohio Valley
east into Carolinas/Mid-Atlantic late next week/weekend. Highs will
begin to trend relatively cooler and below average across portions
of the Northwest and possibly further south along the West Coast
by late next week/weekend as an upper-low from the northeast
Pacific begins to overspread the region.
Putnam
