Flood Potential Outlook
Issued by NWS Binghamton, NY

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FGUS71 KBGM 151714

Winter/Spring Flood Potential Outlook
National Weather Service Binghamton NY
1214 PM EST Thu Feb 15 2018


This is the fourth in a series of regularly scheduled hydrologic
outlooks issued during the Winter and Spring season. This outlook
is designed to provide a generalized assessment of river flood
potential (not flash flooding) across Central New York and
Northeast Pennsylvania for the next two weeks...February 15th
through March 1st.


.The risk of river flooding for the next two weeks is above
average, mainly result from streamflow conditions currently above
normal, and forecast projections of a series of wet weather
systems moving through the region.


.PRECIPITATION: Variable. Precipitation during the first two weeks
of February has been 150-200 percent of normal across the
Susquehanna and Upper Delaware basins, but averaged only about 70
percent of normal from the Chemung basin and Finger Lakes region.
The Upper Mohawk and Oswego basins were about average.

.SNOW COVER AND WATER EQUIVALENT: Below average. The current snow
depth, as of February 15th ranges from about 3 to 10 inches from
the North Branch Susquehanna across the headwaters of the Upper
Delaware basin. Snow depths ranged from 10 to 30 inches along the
southern face of the Tug Hill plateau which drains into the Upper
Mohawk and Oneida basins. Elsewhere, snow depths were generally
under 2-3 inches from the Chemung into the Susquehanna upper main
stem in Pennsylvania. Snow water equivalent ranged from 1-2
inches in the Susquehanna and Delaware headwaters, to a half inch,
or less, across the west central New York basins and northeast
Pennsylvania. This snow water equivalent is considered normal in
the headwaters, but below normal elsewhere.

.RIVER ICE COVER: Below average. While river ice is being observed
along some of the main stem rivers and tributaries in central New
York and northeast Pennsylvania, the ice is not extensive, nor
very thick for what would be expected this time of year. Little
to no new river ice is expected to develop during this outlook
period as forecasts call for above average temperatures.

.STREAMFLOW: Normal to above normal. Streamflow, averaged over
the past 28 days, was generally normal to above normal at a
majority of the stream gauge locations when compared to the long
term history of each gauge.

.SOILS AND GROUNDWATER: Per the Palmer Drought Severity Index,
the deep soil conditions around the area were generally wet from
the Finger Lakes and Chemung basins into a portion of northeast
Pennsylvania, while wetness in the eastern basins was about
average. NY State Mesonet locations indicated the 2cm to 10cm soil
temperatures ranged from about 33-36 degrees. Groundwater levels
were generally normal throughout the area.

.RESERVOIR AND LAKE LEVELS...Normal. NYC Reservoirs were slightly
below the long term median pool height, but still considered in
the normal range for the time of year. The Finger Lakes levels
were about average. Lake Wallenpaupack in NEPA was the only major
lake reporting an above average level.


.FUTURE WEATHER CONDITIONS: The 6 to 14 day outlook calls for
much warmer than average temperatures, and above normal
precipitation. Medium range forecast models suggest a series of
low pressure systems will move through the region during the next
two weeks. After this weekend, the majority of the precipitation
looks as though it will be mainly rain. Given moist soil
conditions in the region, a good portion of any rainfall will
likely run off into the rivers rather easily. This, coupled with
melting of the remaining snow cover, supports the idea of much
above average streamflows, and an increased flood potential
through the end of the month.

ensemble of river forecast systems indicates a low to moderate
risk of river flooding during the next two weeks. A
climatological analysis of flooding, using current hydrologic
conditions compared to historical flows, also suggests an above
average chance for river flooding through the end of February.


This outlook estimates the potential for river and lake flooding
based on a current overview of hydro-meteorological factors which
contribute to flooding.

It is important to note that significant flooding does not occur
from snow melt alone. Rainfall, how much and in how short a
period of time, is the most important factor in determining the
severity of flooding. Specific forecasts of heavy rainfall and
flash flooding are not included in this outlook.

The next Winter/Spring Flood Outlook will be issued by this
office in two weeks, on March 1st 2018. If conditions change in
the interim: Flood Watches, Warnings or Advisories will be issued
as necessary.



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