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FOUS30 KWBC 140738
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
338 AM EDT Sat Jun 14 2025

Day 1
Valid 12Z Sat Jun 14 2025 - 12Z Sun Jun 15 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE MID ATLANTIC AND ALSO THE SOUTHERN PLAINS...


...Mid-Atlantic...

An unsettled weather pattern continues across much of Virginia and
extending into adjacent portions of eastern West Virginia and
northeast North Carolina going into Saturday and Saturday night.
Multiple rounds of slow moving showers and thunderstorms will
develop generally along and ahead of a cold front that is gradually
settling to the south across Virginia. This boundary is
intercepting an anomalously moist airmass with PWs on the order of
1.75 to 2 inches and mixed layer CAPE on the order of 1000 J/kg on
average. The band of highest QPF is expected to be from the
northern Shenandoah Valley to the Hampton Roads area of Virginia,
with 2 to locally 4 inches of rainfall possible. Slow cell motions
and efficient rainfall could result in some hourly rainfall rates
approaching 2 inches per hour, especially where cell mergers occur.
This could result in some instances of flooding, especially across
urban locations and also areas that had heavy rainfall through the
early morning hours Saturday.

...Southern Plains, Southeast, and Tennessee/Ohio Valleys...

A lower tropospheric trough tracks southeastward across the Ohio
Valley over the weekend. This will be traversing a moist
environment with sufficient effective bulk shear along and near
its associated fronts with greater instability. Slow moving
convection and brief organized training is possible. A more
cellular convective mode is likely near the low over the Ohio
Valley, where isolated flash flooding could occur. Along the
southern flanking inflow band, mean wind becomes more westerly and
parallel to developing convection across central and northern
Alabama and Mississippi.

Farther west, cell training due to storms moving south or
southeast down the stationary instability gradient across Kansas
and Oklahoma could be problematic if it occurs for an extended time
period, and some of the recent CAM guidance depicts this scenario,
although there are still considerable mesoscale differences on
placement and magnitude. However, there is high confidence that a
mesoscale convective complex will develop with locally high
rainfall rates. The inherited Slight Risk was maintained although
it is a little larger than the previous issuance.

...Upper Midwest...

A warm advection pattern returns to the region, bringing
a return to more widespread organized convection, mainly during
the 00Z-12Z time period Sunday. Heavy rainfall over this same
region in recent days has resulted in saturated soils in many
cases, and this will increase the vulnerability to flooding, even
though the expected rainfall is not expected to be overly
impressive with mainly 1 to locally 2 inch totals expected, and
therefore a Marginal Risk area remains valid for this time period.

...Central Montana...

A wave of low pressure developing along a frontal boundary should
provide enough forcing to produce some scattered 1 inch rainfall
totals across this region, mainly late Saturday afternoon into the
evening as CAPE increases and dewpoints getting well into the 50s.
Some of the storms that develop may produce high enough rainfall
rates to result in a few instances of flooding.


Hamrick


Day 2
Valid 12Z Sun Jun 15 2025 - 12Z Mon Jun 16 2025

...A SLIGHT RISK OF EXCESSIVE RAINFALL EXISTS FOR THE MID-ATLANTIC
AND ALSO NEAR THE OZARKS...

...Southern Mid-Atlantic States and Central Appalachians...

It remains the case that a corridor of enhanced moisture
convergence will exist across the Mid-Atlantic region going into
Sunday, and thus widespread rain for Father`s Day. The frontal
boundary makes a little more southward progress with the axis of
highest instability expected to generally be south of the
Interstate 64 corridor. Therefore, the main QPF axis is progged
from eastern WV/SW Virginia to near the VA/NC border with
widespread 1-3 inch totals within this band, and locally higher.
The latest HREF probs of flash flood guidance exceedance are
greatest Sunday afternoon/evening across portions of eastern WV and
western VA where antecedent conditions will be quite saturated, and
another area of exceedance across southeast VA. Depending on what
evolves through Saturday night, if the axis of heaviest rainfall on
Sunday is close to or over the previous day`s event, a future
Moderate Risk could be needed, but for now a Slight Risk remains
the best approach.


...Northern Plains into the Midwest and Mid-South...

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 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...

...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.


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