Flood Potential Outlook
Issued by NWS Boston, MA

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WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE TAUNTON MA
1126 AM EST Thu Feb 16 2017

...The Winter/Spring flood potential is normal for most of southern
New England, and slightly below normal across portions of northern
Connecticut, southern Rhode Island and southeast
Massachusetts...

The winter/spring flood potential for southern New England is normal
for most of Massachusetts, northern Rhode Island, and along the
Connecticut River in Connecticut. The flood potential is slightly
below normal across northern Connecticut away from the Connecticut
River, northern Rhode Island, and southeast Massachusetts. The
potential for flooding due to ice jams is much below normal.

The following web site has a map depicting the flood potential
outlook...http://www.weather.gov/nerfc/springfloodpotential

This is the fourth winter/spring flood potential outlook of the 2017
season.  This outlook is based on current and forecast
hydrometeorological conditions. This includes snow cover and snow
water equivalent, stream and river levels and the amount of ice
coverage, recent precipitation and temperatures, and expected
temperatures and precipitation over the next two weeks.

...Recent Precipitation...

January 2017 brought near normal precipitation to southern New
England. Liquid equivalent precipitation ranged from 3.5 to 5 inches
for much of the area, which was mainly within a half inch of normal.
The exception was Rhode Island and southeast Massachusetts, where
higher totals of 5 to 7 inches fell. This precipitation was 1 to
3 inches above normal.

February 2017 precipitation has been above normal month-to-date
across the region. Liquid equivalent totals range mainly from 2
to 3 inches. There were some higher totals within eastern
Massachusetts, where some locales had liquid equivalent totals
that were greater than an inch above normal month-to-date.

Temperatures during January averaged 3 to 5 degrees above normal.
Based on preliminary data, Boston, Worcester, Hartford and
Providence ranked between their 10th and 12th warmest January on
record.

February temperatures month-to-date have averaged near or
slightly below normal.

...Observed snow depths and water equivalents...

Snow depth had increased substantially during the past 2 weeks, and
as of February 17 the area`s snow pack was somewhat above normal
in depth and extent for this time of year. Snow depth ranged from
10 to 20 inches across much of the area. Deeper snow pack of 20 to
near 30 inches was found along the highest terrain of the
Worcester Hills, and in northwest Massachusetts along the east
slopes of the Berkshires.

Snow depth across much of southeast Massachusetts and southern Rhode
Island was somewhat less, predominantly 4 to 10 inches. Then along
the immediate south coasts of Massachusetts and Rhode Island, snow
depth was a trace to a few inches deep. No snow was reported on the
ground at Block Island and Nantucket.

Snow water equivalent ranged from 1.5 to 3 inches across much of
southern New England, with higher amounts of 3.5 to locally over 5
inches across the higher terrain of the east slopes of the
Berkshires, as well as highest terrain of the Worcester Hills. Snow
water equivalent across south coastal RI and south coastal MA was
mainly 2 inches or less.

...River and Ice Conditions...

As of February 17, rivers and streams were running at near normal
levels for this time of year across much of the area. There were
still a some waterways running below normal, especially across
portions of north central Connecticut.

The above normal temperatures during January substantially limited
the amount of river ice development that occurred during the middle
of winter. River ice has grown somewhat in extent and coverage
during the past 2 weeks, but is still much below normal for this
time of year. So heading forward, the flood risk due to ice jams is
much below normal.

...Soil Moisture Conditions and Water Supply...

January brought some short term relief from the drought conditions,
boosting streamflow and ground water, and increasing soil moisture.
While soil moisture as of mid February was still predominantly below
normal, improvement had occurred.

Water supply as of early February was normal to below normal in
Massachusetts, predominantly below normal in Connecticut, and normal
to above normal in Rhode Island.

In Rhode Island, Scituate Reservoir was at 98% of capacity, which
is above normal for this time of year.

In Connecticut, State overall water supply had improved
considerably, to 79.8% of capacity/usable storage as of early
February. However some reservoirs were still low as of early
February. Southington Water Department reported 47% usable
storage, New Britain 41.6 %, and Bristol 55.5%. Manchester Water
Department saw significant improvement, and was at 89% usable
storage as of early February.

In Massachusetts, reservoirs monitored by the State Department of
Conservation and Recreation were mainly at normal to below normal
levels for early February. Quabbin Reservoir was at 79.9% of
capacity as of February 1, with Wachusett Reservoir at 91.3%.

...Temperature and Precipitation Outlook...

Over the next 7 days...temperatures are expected to mainly be within
a few degrees of normal. However milder temperatures are forecast
for Saturday night through Sunday night, and high temperatures on
Sunday may reach 50 degrees in some locales. Mainly dry conditions
are forecast for the region for the next 7 days, with a chance
for precipitation towards the middle of the next workweek.

For the 8 to 14 day outlook, February 23 to March 1, the Climate
Prediction Center calls for both temperatures and precipitation
to average above normal.

...Summary...

Based on information available at this time, the late winter and
spring flood potential is normal across most of Massachusetts,
northern Rhode Island, and along the Connecticut River in
Connecticut. The flood potential is slightly below normal across
northern Connecticut away from the Connecticut River, northern
Rhode Island, and southeast Massachusetts.

Snow depths and snow water equivalents are slightly above normal for
this time of year. This is inclusive of southern New England, as
well as the headwaters of the Connecticut and Merrimack Rivers in
Vermont and New Hampshire.

Over the past 1 to 2 months there has been a steady period of short
term improvements to the longer term drought. Gradual improvements
have been noted in reservoirs, groundwater, rivers and streams,
and there has been an establishment of a snow pack. Thus the
flood potential is mainly near normal. Across areas where the
flood potential is somewhat below normal, there is still more
drought-related buffer available in rivers, streams, groundwater
and reservoirs, should a heavy rainfall or combination rainfall-
snowmelt event materialize.

Mainly dry conditions and near seasonable temperatures are
forecast for the next 7 days, although a warmup is expected for
the latter part of this weekend, and there is a chance for
precipitation towards the middle of the next workweek. The snow
pack will compact and have some melt over the next 7 days,
especially on Sunday. However a rapid melt is not anticipated over
this timeframe.

With the 8 to 14 day outlook indicating above normal temperatures
and above normal precipitation, this timeframe may allow for further
snowmelt to occur.

Keep in mind that heavy rain can cause flooding any time of the
year. Those with interests along rivers and streams should check the
Hazardous Weather Outlook, which highlights any potential flood
events over the next 7 days. Go to http://weather.gov/boston and
click on the option Hazards, then click on Local Outlook.

$$

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