Flood Potential Outlook
Issued by NWS Atlanta, GA

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Hydrologic Outlook
National Weather Service Peachtree City GA
535 AM EDT Tue Sep 15 2020


As Hurricane Sally moves inland and weakens somewhere across
southern Alabama, multiple rounds of heavy rain are expected
across north and central Georgia, starting Wednesday night and
continuing through Thursday. With some model uncertainty continuing
with respect to the track and intensity of Sally, changes to the
forecast rainfall totals can be expected with future forecast packages.

At this time, 2 to 8 inches of rain is expected across a wide
area of north and central Georgia, with locally higher amounts
possible. With the forecast track and movement somewhat uncertain
as the tropical system moves inland, it is difficult to pinpoint
where the highest totals will end up. However, based on the latest
forecast information, it appears the heaviest rain is likely to occur
along the I-85 and I-20 corridors.

Aside from a few localized showers and thunderstorms mainly
during the afternoon and evening, the first half of September has
been relatively dry across much of the area. As a result, soils
have dried out enough to hopefully allow for some initial water
absorption as the heavier rains develop from this next system.
Persistent heavy rainfall over an area will create runoff issues
quickly, especially across urban areas and complex terrain over
north Georgia.

Given the tropical nature of this rain event, there is an
increased risk for flash flooding. In addition, flooding of
larger creeks and streams is likely with the current
expected rainfall amounts, especially where any heavier rain bands
set up as the system approaches the area from the southwest.
Quickly accumulating rainfall can also produce widespread flooding
of smaller, fast-responding creeks. Over urban areas, periods of
heavy rain can overwhelm or clog storm drains and ditches with
debris. Take time ahead of the rain to clear leaves and debris
from these drainage systems.

Stay alert to changing forecasts. The predicted axis of heaviest
rainfall could change over the next 12 to 36 hours. A Flash Flood
or Flood Watch will likely be issued for portions of north and central
Georgia in the next 12 hours or so. Know what county you are in
and the names of rivers and creeks in your area. Don`t be caught
off guard. Take action immediately if a Flash Flood Warning is
issued by going to higher ground, especially if you live near or
in a flood prone area or near a creek or small stream.

For additional hydrologic information, visit our website at
weather.gov/atlanta. Click on the Rivers and Lakes tab under current
weather to access the latest river and precipitation information.


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