Flood Potential Outlook
Issued by NWS Albany, NY
FGUS71 KALY 051657
WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE ALBANY NY
1157 AM EST THU MAR 5 2015
...Winter Spring Flood Potential Outlook 5 for Eastern New York
and Western New England...
This is the fifth of a series of Hydrologic Outlooks issued by
the National Weather Service every two weeks...which refers to
the potential for flooding across eastern New York State...southern
Vermont...Berkshire County Massachusetts...and Litchfield County
Connecticut. The major river basins in this area are the
Hudson...the Mohawk...and the Housatonic.
This outlook is valid for the two-week period March 5 to March 19.
The potential for snowmelt flooding for the winter and spring of
2015 is generally near normal...since snowpack is now near to above
normal. The potential for ice jam flooding is near normal for the
next two weeks.
...Observed Snow Depths and Water Equivalents...
Snow depths between one and a half and two feet were the norm across
elevated terrain in the southern two thirds of the outlook
area...including the Catskills...the Berkshires...and the Litchfield
Hills. These locations are carrying between three and seven...locally
eight...inches of liquid equivalent.
Elsewhere...snow totals in the Adirondacks and southern Green
Mountains measured between a foot and a half and three
feet...containing 2 to 8 inches of snow water equivalent.
These totals bring us into normal to slightly above normal ranges
for this time of year.
...River Flows and Ice Conditions...
Flows in area rivers are below normal with minimal runoff due to
below normal temperatures. Most rivers and streams are ice affected.
River ice cover and thickness is above normal and with cold
temperatures remaining in place for at least the first week of the
outlook period...river ice will remain in place for at least the
next week or so.
...Soil Moisture Conditions and Water Supply...
Soil moisture continues to decline in the outlook area with the
ground frozen and no runoff ongoing. Precipitation totals for the
last 30 days are near normal up to an inch and a half below normal.
New York City water supply reservoirs are at about 74 percent of
capacity as of March 4th. This is about 13 percent below normal
for this time of year. Hudson River-Black River Regulating District
reservoirs range from about 2 feet above target at Great Sacandaga
Lake to over 5 feet below target at Stillwater Reservoir.
...Temperature and Precipitation Outlook...
The forecast for the next week calls for below normal temperatures
and precipitation. However..the official National Weather Service
8-14 day outlook for March 12th through the 18th calls for near
normal temperatures and near to slightly below normal precipitation.
This indicates a warmup from previous outlooks which featured below
to well below normal temperatures.
While the potential for snowmelt flooding is near normal for this
time of year...the overall weather pattern favors colder than normal
temperatures for about the first week of the outlook period. Thus
it is unlikely that we will have enough runoff to cause any
significant rises on area rivers and streams within the first week
or so of the outlook period. However...a return to near normal
temperatures appears likely by midweek next week...with highs in the
upper 30s to upper 40s.
Ice coverage is near 100 percent but with cold temperatures in the
forecast for the next week...no immediate threat for ice jams
exists. However...river ice remains in place and is setting the
stage for potential ice jam issues when temperatures begin to rise.
Any rapid runoff events and dramatic increases in flow would have
the potential to produce ice jam problems...but most likely not in
the first half of the two week outlook period. Again...the second
week of the outlook period could see warmer temperatures but not
necessarily enough to cause rapid ice breakup so monitor forecasts
at weather.gov/albany for the most up to date information.
The sixth Winter Spring Flood Outlook is scheduled for Thursday...
March 19. Extended hydrologic information will be included
in the Hazardous Weather Outlook when necessary.
It is important to remember that heavy rainfall can produce flooding
at any time of year even in areas that have a below normal potential
Observed and forecast river information can be found on our web
page at www.weather.gov/albany.