FOUS30 KWBC 281509
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1009 AM EST Tue Jan 28 2025

Day 1
Valid 12Z Tue Jan 28 2025 - 12Z Wed Jan 29 2025

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Gallina


Day 2
Valid 12Z Wed Jan 29 2025 - 12Z Thu Jan 30 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
NORTH TEXAS AND SOUTHERN OKLAHOMA...

An upper level cutoff low ejecting out of the Southwest into the
Plains will provide forcing for ascent for a developing low over
the Texas and Oklahoma Panhandles Wednesday and Wednesday night.
Return flow of Gulf moisture, warmth, and instability ahead of the
low will advect north across Texas and into Oklahoma and Arkansas
Wednesday and especially Wednesday night. The typical diurnal
strengthening of the LLJ Wednesday night will greatly increase the
coverage and intensity of storms along the developing low's cold
front across Texas, while the warm front locally increases lift
into Oklahoma. The surface low will track north into Colorado,
contributing to a winter storm there. Meanwhile much of the
convection will be associated with the cold/occluded front as it
pushes east towards the Mississippi Valley. Since the upper level
low will be slow-moving (though increasing in forward speed with
time), this will allow the storms that form to train over the same
areas. Training convection will be of greatest concern as the
storms are first forming over Texas. Soils in the area have been
drier than normal, meaning most of the rain will be beneficial,
however where storms train over more flood-sensitive and urban
areas, localized flash flooding remains possible.

Wegman


Day 3
Valid 12Z Thu Jan 30 2025 - 12Z Fri Jan 31 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
MID-SOUTH AND ARKLATEX REGION...

Thunderstorms will likely be ongoing on the northern and western
sides of the Slight and Marginal Risks at the start of the period
Thursday morning. A vigorous upper level cutoff low will begin to
rejoin the jet stream by Friday morning. Before it does so however,
it will provide the forcing for numerous showers and thunderstorms
across much of the Mid-South and Arklatex region. A 50-60 kt LLJ
will pump plentiful Gulf moisture across the Arklatex region
Thursday morning. The trailing cold front will push east across
Oklahoma and Texas, providing ample forcing for the showers and
storms. The primary limiting factor for the storms will be
instability. The greatest instability (around 500 J/kg) will be
across southern and central Texas, while the greatest forcing will
be further north from the Arklatex north and east into the
Mississippi Valley. This disconnect may help to diminish the flash
flooding potential a bit. However, this will be partially offset
by upsloping into the Ozarks across Oklahoma and Arkansas.

It appears that many of the storms will be associated with a line
that moves east across the area. However, storms embedded within
the line may move somewhat parallel to the line towards the
northeast, this will allow for the potential for training. Since
there will be plenty of Gulf moisture (PWATs above 1.5 inches),
the showers and storms will have the potential to cause localized
flash flooding issues, especially in the terrain of the Ozarks
where upsloping may contribute to locally higher rainfall totals.
By Thursday night, the storms will push across the Mississippi
River. By then the eastward forward speed of the storms should
increase, thus diminishing the flooding potential with time.

Wegman

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