Flood Potential Outlook
Issued by NWS Portland, ME

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Winter/Spring Flood Potential Outlook
National Weather Service Gray ME
256 PM EST Thu Feb 16 2017

...WINTER/SPRING FLOOD POTENTIAL OUTLOOK...

The flood potential is above normal for the time of year across
western Maine and New Hampshire.

The potential for ice jam flooding is slightly above normal for
northern New Hampshire and most of western Maine. The potential
for ice jam flooding is below normal for southern New Hampshire.

This is the fourth in a series of regularly scheduled flood
potential outlooks that are issued during the winter and spring
seasons. These outlooks will be issued every two weeks until the
end of the snow melt season, and will assess the potential for
flooding based on a number of factors.

...CLIMATOLOGICAL GUIDANCE...

After a colder than normal December and a very warm January that
saw average temperatures 7 to 8 degrees above normal, February has
been colder than normal and very active. The last 10 days have
seen over 3 feet of snow fall in many areas of western Maine and
eastern New Hampshire. This was the result of an upper level
trough that setup across the northeast and funneled cold canadian
air into the region and brought the storm track very near to
northern New England.

Medium range models indicate that the current pattern will
breakdown with the jet stream retreating into canada resulting in
milder air moving into the northeast.

the official national Weather Service 6 to 10 day and 8 to 14 day
forecast calls for above normal temperatures and above normal
precipitation.

...OBSERVED SNOW DEPTH AND WATER EQUIVALENT...

...NEW HAMPSHIRE...

Snow depth of 1 to 2.5 feet are common across southern and western New
Hampshire with just a few locations reporting less than 1 foot.
From the foothills of the White Mountains north to the Canadian
border snow depth increases to 2 to 4 feet with locally higher
amounts above 2000 feet.

Snow water equivalent ranges from 2 to 5 inches in southern New
Hampshire, and increase to 4 to 9 inches from central New
Hampshire north to the Canadian border. Higher amounts exits above
2000 feet. Moose Falls near the Canadian border reported 44.4
inches of snow with 11.5 inches of snow water equivalent.

Snow depth and water equivalent is mostly above normal for the
time of year.

...WESTERN MAINE...

Snow depth ranges from 1 to 3 feet in southern Maine. From the
foothills to the Canadian border snow depth ranges from 3 to 5
feet with locally higher amounts. This morning Andover in central
Oxford county reported 79 inches of snow depth and Kingfield
reported 68 inches of snow depth.

Snow water equivalents range from 3 to 6 inches in southern and
coastal locations up to 6 to 10 inches from the foothills to the
Canadian border. Locally 12 inches of water equivalent exists
above 2000 feet.

Snow depth and water equivalent are above normal for the time of
year.

...SOIL MOISTURE AND WATER SUPPLY CONDITIONS...

Soil moisture anomaly maps indicate that soil moisture is normal
across western Maine and most of New Hampshire except Cheshire
county where it is slightly below normal.

The long term term Palmer Drought Severity Index shows normal
conditions across Maine and New Hampshire.

Reservoirs in the Kennebec River basin are above normal for the
time of year.

Reservoirs in the Androscoggin River basin are 54.4 percent full
which is 9.7 percent above normal.

At the end of January First Connecticut Lake in northern New
Hampshire was 124 percent of normal and 53 percent full. Lake
Francis was 121 percent of normal and 69 percent full. Lake
Winnipesaukee was 75 percent of normal and 67 percent full.

Groundwater levels courtesy of the USGS show a mix of above and
below normal groundwater. However at this time there is enough
water stored in the snowpack to see a normal recharge this
spring.

...RIVER AND ICE CONDITIONS...

RIVER FLOWS ARE NEAR NORMAL FOR THE TIME OF YEAR.

Substantial ice cover exists in central and northern areas of both
Maine and New Hampshire. Ice thickness is from 1 to 2 feet thick.
A small ice jam exists on the Kennebec River at Augusta.

...IN CONCLUSION...

Based on the above information, the winter/spring flood potential
is above normal for the time of year.

It is important to note that major flooding does not occur from
snowmelt alone. Rainfall, how much and in how short a period of
time is the most important factor in determining the severity of
flooding.

Another Winter/Spring Flood Potential Outlook will be issued by
8 AM Friday March 3.

$$

TFH



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