Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1058 AM EST Wed Nov 4 2026
Day 1
Valid 16Z Wed Nov 04 2026 - 12Z Thu Nov 05 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR A PORTION OF
SOUTHEAST FLORIDA AS WELL AS FOR PORTIONS OF THE OHIO AND TENNESSEE
VALLEYS AND SOUTHERN APPALACHIANS...

16Z Excessive Rainfall Discussion...
Composite radar clearly depicted a slow-moving cold front extending
north to south across the Ohio and the Tennessee Valleys with
showers and some embedded thunderstorms in the warm air ahead of
the front. 12Z soundings showed the pre-frontal airmass
characterized by precipitable water values of 1.75+ inches feeding
into the Tennessee Valley from the south with sufficient
instability to support local downpours but the dry antecedent
conditions should mitigate the overall flash flood threat to the
point where a Marginal risk remains appropriate.

In southeast Florida...the on-shore flow regime will continue to
support localized downpours in and near the urban corridor into the
late afternoon or early evening.

Bann

Previous Excessive Rainfall Discussion...

...Tennessee and Ohio Valleys and Southern Appalachians...

A slow-moving cold front moving across the lower Ohio and
Tennessee Valleys this morning will continue to push east into the
upper valleys and southern Appalachians today. Training showers
with a few embedded thunderstorms are expected to persist through
the day. Those thunderstorms could produce rainfall rates of 1-1.5
inches at times, which could cause an isolated flash flooding
threat. This is mostly due to the influx of abundant Gulf moisture
with PWATs to 1.75 inches. Working against significant flooding are
the very dry antecedent soil conditions from an entire second half
of October with very little to no rain. Instability will also limit
rainfall rates, as values in most of the Marginal Risk area
struggle to get even to 1,000 J/kg. The Southern Appalachians could
have a bit higher flash flooding risk due to the terrain influences
and added upslope wringing out additional rainfall on those local
areas.

...Southeast Florida...

A final day of continued onshore light easterly flow with an
abundance of tropical moisture will once again promote any storms
having a heavy rainfall and consequent flash flooding risk today.
As has been the case the past few days, the storms will form over
the straits between the northwest Bahamas and Florida, then drift
east towards the urban corridor between West Palm Beach and Miami.
This area has been in this pattern for over a week, so the soils in
this normally flood-resistant area are fully saturated. Thus, any
new rainfall will immediately convert to runoff. While storm
coverage is expected to be much more isolated than previous days,
the potential for flash flooding development remains high enough to
keep the inherited Marginal Risk ongoing with few changes.
Fortunately by tomorrow, developing northerly flow will advect
significantly drier air into south Florida, allowing the area to
begin a much drier period.

Wegman


Day 1 threat area: www.wpc.ncep.noaa.gov/qpf/94epoints.txt