FOUS30 KWBC 220826
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
426 AM EDT Wed Jul 22 2026

Day 1  Valid 12Z Wed Jul 22 2026 - 12Z Thu Jul 23 2026

...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR SOUTHEASTERN
VIRGINIA AND EXTREME NORTHEASTERN NORTH CAROLINA...

...Southeast...

A strong but painfully slow moving cold front draped across
Virginia today will continue to act as a train track along which
numerous showers and thunderstorms will move throughout the day and
into tonight. It's probable that many areas from western North
Carolina through Raleigh and into the Hampton Roads area of
southeast Virginia will see more time over the next 24 hours seeing
moderate to heavy rainfall than dry time. The heaviest and most
persistent rainfall will be into extreme northeastern North
Carolina and much of southeastern Virginia southeast of Richmond
today. The Hampton Roads metro appears to be the most at risk of
the metro areas expected to be impacted by heavy rains today. It's
likely areal averages in the Hampton Roads area will exceed 3
inches today through tonight. Given both the persistence of the
heavy rain and urban concerns, the inherited Moderate Risk area
will remain unchanged with this update, generally following the
state line east from I-95 to the mouth of the Chesapeake.

Elsewhere the Slight Risk area extending from northern Georgia to
the Delmarva was shrunk both on the north and south sides with this
update. The CAMs guidance are in good agreement on the corridor
where heavy rain and flash flooding will be, increasing the
confidence that a smaller latitudinal range will be covered by the
heavy rain. As such, the southeastern corner of NC and all but
northern SC were removed from the risk categories as the heaviest
rains will stay north of those areas for today. They'll get their
turn in the coming days. The length of the front will promote heavy
rain development towards the west, and as such the Slight was
expanded west into northeastern Alabama with this update, where the
combination of the front and topography will both support areas of
heavy rain and widely scattered instances of flash flooding.

...Intermountain West...

The Slight Risk area covering an expansive area of the
Intermountain West from southwestern Montana south through
northwestern New Mexico was largely unchanged with this update.
However, in coordination with ABQ/Albuquerque, NM forecast office,
the Slight Risk area was expanded south along the AZ/NM state line
with this update. Plentiful burn scars, relatively little amounts
of rain it's taken in some areas to cause flash flooding, and many
areas not seeing recent flooding at all are all contributing
factors to the Slight Risk upgrade. Meanwhile further north, the
heaviest rainfall totals will be tied to the topography in many
areas from the Bitterroots through Yellowstone, much of Utah and
western Colorado. With sufficient upper level forcing helping the
storms to form and cause flash flooding, it's probable in many
instances that any storms that start along the topography will move
off the mountains towards the northeast, so lower elevation valleys
in between also remain in the Slight Risk for flooding.

...Gulf Coast/Tropical Storm Bertha...

T.S. Bertha will continue to struggle from strong northeasterly
shear pulling nearly all of the significant associated rainfall
south over the open waters of the Gulf. With little rain expected
along the Gulf Coast, the inherited Marginal remains little
changed. The Marginal mostly covers the fact that any significant
tropical cyclone carries inordinate amounts of atmospheric
moisture, even when being sheared. That moisture can easily support
heavy rainfall, even if isolated, so the Marginal threat remains.

Wegman
 

Day 2  Valid 12Z Thu Jul 23 2026 - 12Z Fri Jul 24 2026

...THERE'S A MODERATE RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
EASTERN NORTH CAROLINA...

...Southeast...

A strong and very slow moving cold front draped across portions of
the Mid-Atlantic on Wednesday makes only very slow progress through
the day Thursday across far southern Virginia and northwestern
North Carolina. A second day of intense rainfall in the form of
seemingly endless trains of storms will impact much of the
Carolinas on Thursday. The good news is the southward progress of
the front on the order of about 50 miles or so will spare most of
Virginia much heavy rainfall for yet another day. However, this
means the heavy rain simply impacts areas further south across much
of North Carolina and northern South Carolina. Unfortunately there
looks to be some overlap in the heavy rainfall footprints from
Wednesday into Thursday, particularly in northeastern North
Carolina, likely extending from Norfolk south and east. Once again
the heaviest rainfall amounts will likely concentrate along the
coast. As such the Moderate Risk for this period was also
unchanged, focused from I-95 east and from I-40 north and east.

Further west, a similar situation remains as on Wednesday.
Painfully slow southward movement means many of the same areas get
hit with heavy rains again on Thursday as on Wednesday. The Slight
Risk was expanded west along the front due to the large amounts of
atmospheric moisture in place immediately ahead of the front. Many
areas have PWATs above 2 inches. The Slight Risk area includes
metros Birmingham, AL, Atlanta, and into Charlotte, NC. All 3 of
these metros have some risk of training storms, with Charlotte the
highest of those 3.

...Central Plains...

A pair of nocturnal MCSs, one Wednesday night into Thursday
morning, and a second much stronger one Thursday night into Friday,
will impact portions of southeastern Nebraska, northeastern Kansas,
and into small portions of Iowa and Missouri through the period.
These back-to-back MCSs will sufficiently soak the soils such that
the heavy rain with Thursday Night's MCS will cause widely
scattered instances of flash flooding, especially where urban areas
such as Lincoln, Topeka, St. Joseph, and possibly Omaha and Kansas
City are impacted. The area of the Slight was adjusted, but remains
little changed with this update. The isolated flash flooding threat
represented by the Marginal extends well west of there through
nearly all of Wyoming and Colorado. While the flooding threat
diminishes considerably in these states compared with Wednesday,
the leftover saturated soils and still likely formation of showers
and storms will keep an isolated flash flooding threat going.

...Bertha/South Texas...

Latest CAMs guidance are starting to come into agreement on a
solution that keeps the circulation of Bertha intact over the
northwestern Gulf before the westward moving storm moves inland in
Texas near or south of Houston. As such, the persistent convection
that continues to focus south/southwest of the center eventually
impacts land areas, in this case in south Texas. A Marginal Risk
covering much of South Texas was introduced with this update. It's
likely that a Slight Risk upgrade will be needed with future
updates, short of a northward jog in the guidance that kills off
the rain much earlier, as the guidance had been showing in recent
days. The area most likely to see that upgrade is around Corpus
Christi through Victoria.

Wegman
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