Flood Potential Outlook
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FGUS71 KPBZ 171330

Winter/Spring Flood Potential Outlook
National Weather Service Pittsburgh PA
830 AM EST Fri Feb 17 2017


Little to no rain is forecast during the next week. As a result,
there is no risk for flooding into the middle of next week.

For the remainder of February and into early March, 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.

In addition, a 90-day water resources outlook is issued monthly.

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, very mild temperatures have occurred since mid-
December 2016 leading to below normal snowfall and no ice
development on rivers in the Ohio River Basin.

Precipitation for 2017 has been above normal (~150%) across the
Upper Ohio Valley. The remainder of the Ohio River Basin has been
below normal in precipitation (50 to 75%).

Soils are wet across the Upper Ohio River Basin. Across the
remainder of the Ohio River Basin, soil are moist.


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, this pattern has resulted in predominantly fast zonal flow
across the United States, producing weaker progressive systems in
the Ohio River Basin (little amplification and strengthening of
low pressure systems as well as lack of influx of moisture from
the Gulf of Mexico). This setup has lead to below normal rainfall.
Furthermore, this pattern will likely persist for the remainder of
this winter leading to, at best, a normal risk of flooding.

Middle to late February; no flooding
Later February to early March; normal to below risk for flooding.

The next update will be issued on March 4, 2017 unless conditions
warrant an earlier issuance. |


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