Flood Potential Outlook
Issued by NWS Upton, NY

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FGUS71 KOKX 181949

250 PM EST Thu Jan 18 2018

...Winter/Spring Flood Potential Outlook...

This is the second winter/spring flood potential outlook in a
series of routine winter/spring flood potential statements
intended to provide insight into the likelihood of river flooding
(not flash flooding) over the Lower Hudson River Valley, Northeast
New Jersey, Southern Connecticut, New York City and Long Island
over the next two weeks.

This outlook is based on current assessment of Hydro-
Meteorological factors which contribute to river flooding. These
factors include recent precipitation, soil moisture, snow cover
and snow water equivalent, river ice, stream flow and future
weather conditions. This outlook does not address the severity of
any future river flooding.

The latest climate prediction center 6 to 10 day outlook valid
from January 23rd  through January 27th  suggests above normal
temperatures and above normal precipitation across the Hydrologic
Service Area. The 8 to 14 day outlook valid from January 25th
January 31st suggests a continuation of above normal
temperatures and precipitation across the Hydrologic Service

Heavy rainfall is the primary factor which leads to river
flooding. It is important to note that heavy rainfall can rapidly
cause river flooding any time of the year, even when overall river
flooding potential is considered low or below normal.

Current flooding - None.

Precipitation - Precipitation departures across the Hydrologic
Service Area during the last 30 days ending on January 17th were
normal to 2 inches below normal.

Snow depth and Water equivalent - There is currently 1 to 4 inches
of snow on the ground across Northern Lower Hudson River Valley with
0.50 inches of water equivalent. Across northeast New Jersey,
Southern Lower Hudson River Valley and Southern Connecticut corridor
there is currently a trace to 2 inches of snow on the ground with
less than 0.25 inch of water equivalent. Across New York City and
Long Island there is up to a trace of snow on the ground with less
than a tenth of an inch of water equivalent.

River flows - Across the local Hydrologic Service Area, rivers
and streams are running below normal. Real-Time Water data can be
found by visiting the USGS at www.usgs.gov/water.

Soil moisture - Normal to Below normal. Soil moisture and drought
related data and charts can be seen at: www.cpc.ncep.noaa.gov and

Reservoir conditions - Reservoir levels across the New York City
water supply system are 6 percent below normal. Reservoir levels
across the combined 13 Northeast New Jersey reservoirs are 16
percent below normal.

Summary - Long term models show a system that may impact the area
during the first week of the outlook period producing moderate to
heavy rainfall. The combination of snowmelt and heavy rainfall will
result in possible flooding across the Hydrologic Service. River
movement is also likely during this period. Otherwise, expect above
normal precipitation and temperatures across the Hydrologic Service
Area during this two week outlook period.

For complete weather information, visit our web site at:

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The next Winter/Spring Flood Outlook will be issued by this
office in two weeks, on February 1st, 2018.


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