Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Wed May 20 2026
Day 2
Valid 12Z Thu May 21 2026 - 12Z Fri May 22 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
SOUTHERN PLAINS AND PINEY WOODS REGIONS...

...Southern Plains into the Piney Woods...

The dry line across western Texas and Oklahoma will make a big push
to the east through the Day 2/Thursday period. The former cold
front over eastern Texas will retreat as a warm front towards the
north and as renewed push of deep Gulf moisture advects northward
with the low level jet. Further, a deep positively tilted longwave
trough will eject into the Plains from the Rockies during this
period. The combination off all of these factors will result in a
large and widespread area of convection stretching from the Gulf
Coast of Texas north across eastern Oklahoma and Kansas, as far
north as Kansas City.

Starting from the south, the convection along the Texas Gulf coast
will be associated with the dry line pushing quickly east and
running into plentiful Gulf moisture ahead of it. Expect most of
the storms from Houston south and west to be fast movers with the
dry line. Most of these storms will impact coastal communities
Thursday morning. Further north, there will likely be convection
ongoing at the start of the period across north Texas (near the
Wichita Falls area) and into southwestern Oklahoma. These storms
will increase in coverage through the morning as they progress over
central Oklahoma. Meanwhile by afternoon, the storms will blossom
over northeast Texas and down into northern Louisiana. With
moisture continuing to advect north, expect numerous clusters of
storms over much of eastern Oklahoma, eventually moving into
western Arkansas in the early evening. These areas got pockets of
1-3 inches of rain yesterday, so the newly saturated soils across
western Arkansas should support widely scattered instances of flash
flooding as multiple rounds of storms move through, and they
backbuild south and west. Due to the southerly flow of Gulf
moisture, some convection should also progress northward into
eastern Kansas and western Missouri through the evening. By this
far north instability will be lacking, so not expecting
particularly heavy rain, but all of the stronger storms to the
south will have merged into a larger area of moderate rain into
Kansas and Missouri, which have also seen heavy rains lately,
supporting Slight Risk levels of flash flooding. The steady rain
there could continue well into Thursday night.

...Southern Appalachians...

The clash of a cool air mass behind a back door cold front over
Virginia and tropical Atlantic moisture across the Southeast
characterized by PWATs over 1.5 inches will support areas of
showers and storms across portions of southwest Virginia, western
North Carolina, and perhaps into far eastern Tennessee Thursday
afternoon into Thursday night. Training convection along the front
will be likely, especially along the Virginia/North Carolina border
area, where the topography of the southern Appalachians could
locally further enhance rainfall rates. Instability will be
marginal however due to extensive cloud cover over this area.
While the meteorology may support a bit more widespread flooding,
the hydrology will be strongly working against that. A long-term
drought over the area and extremely dry soils compared to
climatology will make much of the rain expected in this area
beneficial. However, due to training, plentiful moisture that will
support areas of heavy rainfall, and the topography, isolated
instances of flash flooding are probable. For now the area remains
in a Marginal Risk, but a Slight may need to be considered if
forecast rainfall amounts in this area increase appreciably over
the next day or so.

Wegman

Day 2 threat area: www.wpc.ncep.noaa.gov/qpf/98epoints.txt