Flood Potential Outlook
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FGUS71 KPBZ 161249

Winter/Spring Flood Potential Outlook
National Weather Service Pittsburgh PA
849 AM EDT Thu Mar 16 2017


The winter spring flood outlook through March 31 the flood
potential is normal for most of the Ohio River basin.

A normal risk for flooding means occasional flooding could occur
with water levels having minor impacts.

For the long-range river outlooks and the probability of exceeding
floodstage or the chances of flooding relative to normal at
specific forecast points during the next 90 days, refer to
www.weather.gov/ohrfc and click on the 90-day river outlook on
the left hand side of the page. Click on the flood chc vs normal
to view the risk of flooding with respect to normal.

Flood outlooks are issued bi-weekly by the National Weather
Service during winter and early spring to summarize basin
hydrometeorological conditions and to assess the potential for
winter/spring flooding. The outlooks are based on current and
forecast conditions during the outlook period.

Factors considered in assessing flood potential are: (1)
antecedent conditions, (2) past precipitation, (3) recent
streamflows and reservoir levels, (4) soil moisture, (5) water
content of the snow pack, (6) ice conditions on the rivers and
(7) future precipitation.

Meteorologically, the winter of 2016/17 was very mild in the Ohio
Valley leading to much below normal snowfall and no ice
development on rivers.

Precipitation for the winter of 2016/17 has been above
normal(>133% of normal) across the Upper Ohio Valley.

Soils are moist to wet across the Upper Ohio River Basin.


Strong onshore flow along the west coast of the United States has
precluded intrusions of arctic air masses on a frequent basis this
winter. The lack of a snowpack considerably lessens the chance for
flooding in the Ohio River Basin.

Also...the predominantly fast zonal flow across the United States
has frequently produced progressive systems in the Ohio River
Basin resulting in little amplification and strengthening of low
pressure systems as well as a lack of influx of moisture from the
Gulf of Mexico. This pattern has lead to few heavy precipitation
events in the Ohio Valley this past winter.

Early spring risk for flooding is normal for flooding across most
of the Ohio River Basin.

The next update will be issued on or around March 31, 2017,
unless conditions warrant an earlier issuance.


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