Extended Streamflow Guidance
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WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE
NORTHEAST RIVER FORECAST CENTER TAUNTON MA
730 PM EST WED FEB 15 2017

...FOR OFFICIAL NATIONAL WEATHER SERVICE USE ONLY...

WINTER/SPRING FLOOD POTENTIAL FOR THE NORTHEASTERN U.S. /4/

THE WINTER/SPRING FLOOD POTENTIAL FOR THE NORTHEASTERN UNITED STATES
IS ABOVE NORMAL FOR ALL OF MAINE AND ADJACENT AREAS OF NORTHERN NEW
HAMPSHIRE AND NORTHEAST VERMONT. THE WINTER/SPRING FLOOD POTENTIAL
IS SLIGHTLY ABOVE NORMAL FOR THE TUG HILL PLATEAU AND SOUTHERN
ADIRONDACK MOUNTAIN REGIONS OF NEW YORK STATE.

ACROSS THE REMAINDER OF THE NERFC SERVICE AREA...THE WINTER/SPRING
FLOOD POTENTIAL IS NEAR NORMAL EXCEPT ACROSS PORTIONS OF SOUTHEAST
NEW YORK STATE AND SOUTHERN NEW ENGLAND WHERE IT REMAINS LOCALLY
BELOW NORMAL.

THE POTENTIAL FOR FLOODING DUE TO ICE JAMS IS NEAR TO SLIGHTLY ABOVE
NORMAL IN THE NEAR TERM ACROSS THE TUG HILL PLATEAU REGION OF NEW
YORK STATE AND NEAR TO SLIGHTLY ABOVE NORMAL IN THE LONG TERM ACROSS
MAINE...NORTHERN NEW HAMPSHIRE...NORTHERN VERMONT AND NORTHERN NEW
YORK STATE. FOR MOST OF CENTRAL AND SOUTHERN NEW ENGLAND AND NEW
YORK STATE FROM THE MOHAWK RIVER SOUTH AND WEST...THE POTENTIAL FOR
FLOODING DUE TO ICE JAMS REMAINS BELOW NORMAL TO NON-EXISTENT.

...CLIMATE GUIDANCE...

DURING THE FIRST TWO WEEKS OF FEBRUARY...MARKEDLY COLDER
TEMPERATURES AND STORMY CONDITIONS BECAME ESTABLISHED ACROSS THE
SEVEN STATE REGION OF NEW ENGLAND AND NEW YORK STATE. THE PACIFIC
NORTH AMERICA ( PNA ) PATTERN BECAME INCREASINGLY POSITIVE WHICH
FAVORS A DEEP EAST COAST TROUGH AND IS FORECAST TO SPIKE OVER THE
NEXT FEW DAYS COINCIDING WITH ANOTHER SIGNIFICANT STORM SYSTEM
POISED TO HIT MAINE WITH MORE HEAVY SNOW. GOING
FORWARD...HOWEVER...MEDIUM RANGE CLIMATE ENSEMBLES ARE SIGNALING A
WEAKENING OF THIS POSITIVE PNA PATTERN AND A RELAXING OF THE EASTERN
UNITED STATES TROUGH. WITH THE NORTH ATLANTIC OSCILLATION PATTERN (
NAO ) FORECAST TO REMAIN PREDOMINANTLY POSITIVE...WE ARE FAIRLY
CONFIDENT THAT THE JET STREAM WILL RETREAT NORTH AND ALLOW MUCH
MILDER AIR TO WORK INTO THE NERFC SERVICE AREA THROUGH THE END OF
FEBRUARY.

NOAA`S CLIMATE PREDICTION CENTER`S ( CPC ) OFFICIAL 8 TO 14 DAY
TEMPERATURE OUTLOOK IS IN STRONG AGREEMENT WITH THE ABOVE ASSESSMENT
AS IT CALLS FOR TEMPERATURES TO AVERAGE ABOVE NORMAL ACROSS ALL OF
NEW YORK STATE AND NEW ENGLAND FROM 22-28 FEBRUARY 2017.
PRECIPITATION DURING THE SAME TIME PERIOD IS EXPECTED TO AVERAGE
ABOVE NORMAL AS WELL EXCEPT ACROSS PORTIONS OF EASTERN NEW ENGLAND
WHERE IT MAY REMAIN CLOSE TO NORMAL.

SO...IN SUMMARY...ONCE WE EXIT THIS UPCOMING WEEKEND...WE WILL
LIKELY SEE THE SNOWPACK BEGIN TO MELT OFF ACROSS MUCH OF NEW YORK
STATE AND AT LEAST CENTRAL/SOUTHERN NEW ENGLAND WITH PERHAPS SOME
SIGNIFICANT STORMINESS DURING THE LAST WEEK OF THE MONTH.

...OBSERVED SNOW DEPTHS AND WATER EQUIVALENTS...

OUTSIDE OF WESTERN NEW YORK STATE...THE SNOWPACK HAS BUILT OVER THE
PAST FEW WEEKS AND IS CURRENTLY AT ITS WINTER MAXIMUM ACROSS MOST
ALL OF NEW ENGLAND AND EASTERN NEW YORK STATE. SNOW DEPTHS ARE WELL
ABOVE NORMAL ACROSS MAINE AND ADJACENT NORTHERN NEW HAMPSHIRE FOR
MID-FEBRUARY.

...NEW YORK STATE...

SNOW COVERS JUST ABOUT ALL OF NEW YORK STATE AS OF 15 FEBRUARY 2017
EXCEPT ACROSS PORTIONS OF WESTERN NEW YORK STATE WHERE THE GROUND IS
MOSTLY BARE. FROM THE FINGER LAKES WEST TO THE SHORELINE OF LAKE
ERIE...JUST A FEW INCHES OF SNOW AT BEST COVER THE GROUND. FURTHER
EAST...FROM THE MOHAWK RIVER SOUTH AND EAST...SNOW DEPTHS AVERAGE
BETWEEN 8 AND 16 INCHES EXCEPT ACROSS LONG ISLAND WHERE DEPTHS ARE
MOSTLY BELOW 6 INCHES NOW. 6 TO 12 INCHES OF SNOW IS THE NORM ACROSS
THE SAINT LAWRENCE VALLEY IN EXTREME NORTHERN NEW YORK STATE. THE
DEEPEST SNOW DEPTHS IN NEW YORK STATE OCCUR FROM THE TUG HILL
PLATEAU EAST OF LAKE ONTARIO INTO THE ADIRONDACK MOUNTAIN RANGE
WHERE AMOUNTS OF 1 TO 2 FEET ARE COMMON IN THE VALLEYS...INCREASING
TO BETWEEN 2 AND 3 FEET ABOVE 1500 FEET WITH LOCALLY HIGHER AMOUNTS.
SNOW DEPTHS ARE NEAR TO A BIT ABOVE NORMAL EAST AND NORTH OF THE
FINGER LAKES IN NEW YORK STATE BUT MARKEDLY BELOW NORMAL FROM THE
FINGER LAKES WEST TO THE SHORELINE OF LAKE ERIE.

FROM THE MOHAWK RIVER SOUTH AND EAST IN NEW YORK STATE...SNOW WATER
EQUIVALENTS AVERAGE BETWEEN 1 AND 3 INCHES WITH LOCALIZED AMOUNTS
NEAR 4 INCHES IN THE HIGHER TERRAIN OF THE CATSKILL MOUNTAINS AND
HIGH TERRAIN NORTH OF BINGHAMTON. SNOW WATER EQUIVALENTS ALSO
AVERAGE BETWEEN 1 AND 3 INCHES ACROSS THE SAINT LAWRENCE VALLEY IN
FAR NORTHERN NEW YORK STATE. FROM THE FINGER LAKES WEST TO THE
SHORELINE OF LAKE ERIE...SNOW WATER EQUIVALENTS ARE BASICALLY AN
INCH OR LESS. THE HIGHEST SNOW WATER EQUIVALENTS ACROSS THE EMPIRE
STATE ARE FOUND IN THE TUG HILL PLATEAU AND ADIRONDACK MOUNTAIN
RANGE. IN THESE AREAS...VALLEY LOCATIONS REPORT BETWEEN 2 AND 4
INCHES OF WATER IN THE SNOWPACK WHILE ABOVE 1500 FEET...THOSE VALUES
INCREASE TO BETWEEN 4 AND 8 INCHES WITH LOCALIZED HIGHER AMOUNTS
ALONG THE RIDGES OF THE TUG HILL PLATEAU. SNOW WATER EQUIVALENTS ARE
NEAR TO SLIGHTLY ABOVE NORMAL FOR THE TUG HILL AND SOUTHERN
ADIRONDACK MOUNTAINS AND IN FACT NEAR NORMAL FOR MOST AREAS EAST OF
THE FINGER LAKES. FROM THE FINGER LAKES WEST IN NEW YORK
STATE...HOWEVER...SNOW WATER EQUIVALENTS ARE BELOW NORMAL FOR THE
MIDDLE OF WINTER.

...SOUTHERN NEW ENGLAND...

CLOSE TO THE COAST IN SOUTHERN NEW ENGLAND...SNOW DEPTHS ARE NEAR OR
LESS THAN 10 INCHES WITH JUST ABOUT NO SNOW LEFT ON THE GROUND
ACROSS PORTIONS OF CAPE COD AND THE ISLANDS IN SOUTHEASTERN
MASSACHUSETTS. SNOW DEPTHS ACROSS THE REMAINDER OF SOUTHERN NEW
ENGLAND AVERAGE BETWEEN 10 AND 20 INCHES WITH LOCALIZED 2 FOOT
AMOUNTS IN THE HIGHER TERRAIN OF NORTH CENTRAL AND NORTHWEST
MASSACHUSETTS. SNOW DEPTHS ACROSS SOUTHERN NEW ENGLAND ARE NOT TOO
FAR FROM NORMAL FOR MID-FEBRUARY.

NEAR THE COAST IN SOUTHERN NEW ENGLAND...SNOW WATER EQUIVALENTS
AVERAGE BETWEEN A TRACE AND 2 INCHES. SNOW WATER EQUIVALENTS
INCREASE ACROSS INTERIOR SOUTHERN NEW ENGLAND WHERE MOST PLACES
REPORT BETWEEN 2 AND 4 INCHES OF WATER LOCKED UP IN THE RELATIVELY
NEW SNOWPACK. HIGHER AMOUNTS TO NEAR 6 INCHES ARE FOUND ABOVE 1500
FEET IN THE BERKSHIRE MOUNTAINS OF NORTHWEST MASSACHUSETTS. SNOW
WATER EQUIVALENTS ARE CLOSE TO NORMAL FOR MID-WINTER ACROSS SOUTHERN
NEW ENGLAND EXCEPT FOR SOUTHWEST MASSACHUSETTS AND NORTHWEST
CONNECTICUT WHERE THEY ARE A BIT BELOW NORMAL.

...VERMONT...

WEST OF THE GREEN MOUNTAIN SPINE IN VERMONT...SNOW DEPTHS AVERAGE
BETWEEN 8 AND 16 INCHES. ACROSS THE REMAINDER OF THE GREEN MOUNTAIN
STATE...SNOW DEPTHS AVERAGE BETWEEN 1 AND 3 FEET WITH HIGHER AMOUNTS
IN THE MOUNTAINS AND NORTHEAST KINGDOM OF VERMONT. FOR INSTANCE...AT
3000 FEET ON MOUNT MANSFIELD IN NORTHERN VERMONT...SNOW DEPTHS ON 14
FEBRUARY 2017 WERE OBSERVED TO AVERAGE 72 INCHES WITH 42 INCHES A
BIT LOWER AT 1550 FEET. 43 INCHES OF SNOW WAS OBSERVED ON THE GROUND
THIS MORNING AT WALDEN IN THE NORTHEAST KINGDOM OF VERMONT. ACROSS
VERMONT...SNOW DEPTHS ARE NEAR NORMAL WEST OF THE GREEN MOUNTAINS
BUT TRANSITION TO ABOVE NORMAL ABOVE 2000 FEET AND ALSO IN THE
NORTHEAST KINGDOM.

WEST OF THE GREEN MOUNTAIN SPINE...THE SNOWPACK CONTAINS...ON
AVERAGE...1 TO 3 INCHES OF WATER. ACROSS THE REMAINDER OF THE
STATE...SNOW WATER EQUIVALENTS OF 3 TO 6 INCHES ARE THE NORMAL BELOW
1500 FEET WITH 5 TO 10 INCHES ABOVE THAT WITH EVEN HIGHER AMOUNTS
ABOVE 2500 FEET. AGAIN...ON MOUNT MANSFIELD...THE 72 INCH SNOW DEPTH
AT 3000 FEET CONTAINED 19+ INCHES OF WATER WITH ABOUT 9 INCHES AT
THE 1550 FOOT SAMPLING SITE. SNOW WATER EQUIVALENTS ARE NEAR NORMAL
WEST OF THE GREEN MOUNTAINS AND NEAR TO ABOVE NORMAL IN THE HIGH
TERRAIN AND NORTHEAST KINGDOM OF VERMONT.

...NEW HAMPSHIRE...

ACROSS SOUTHERN AND WESTERN NEW HAMPSHIRE...SNOW DEPTHS OF 1 TO 2.5
FEET ARE THE NORMAL WITH JUST A FEW LOWER READINGS. THESE VALUES
INCREASE FROM JUST SOUTH OF THE WHITE MOUNTAINS NORTH ALONG THE
BORDER WITH MAINE WHERE AVERAGE DEPTHS ARE BETWEEN 2 AND 4 FEET NOW
WITH LOCALLY HIGHER AMOUNTS ABOVE 2000 FEET. SNOW DEPTHS ACROSS NEW
HAMPSHIRE ARE NOW NEAR TO ABOVE NORMAL EVERYWHERE.

FOR MOST OF SOUTHERN AND WESTERN NEW HAMPSHIRE...SNOW WATER
EQUIVALENTS AVERAGE BETWEEN 2 AND 5 INCHES. THESE VALUES INCREASE TO
BETWEEN 4 AND 8 INCHES ALONG THE MAINE BORDER FROM CENTRAL NEW
HAMPSHIRE NORTH THROUGH THE WHITE MOUNTAINS WITH LOCALIZED 10+ INCH
AMOUNTS ABOVE 2000 FEET IN THE WHITE MOUNTAINS. MUCH LIKE SNOW
DEPTHS...SNOW WATER EQUIVALENTS ARE NOW RUNNING NEAR TO ABOVE NORMAL
ACROSS ALL AREAS OF THE GRANITE STATE.

...MAINE...

AS OF THIS WRITING...ANOTHER STORM IS POISED TO DROP APPRECIABLE
SNOW ON AREAS IN WESTERN/SOUTHERN MAINE. SNOW DEPTHS ALONG THE COAST
OF MAINE ARE RUNNING BETWEEN 1 AND 3 FEET BUT THOSE DEPTHS INCREASE
TO BETWEEN 2 AND 5 FEET OVER INTERIOR MAINE WITH AMOUNTS TO NEAR 6
FEET NOT UNCOMMON ABOVE 1500 FEET IN THE WESTERN AND CENTRAL MAINE
HIGHLANDS. FOR INSTANCE...ANDOVER...IN THE WESTERN
MOUNTAINS...REPORTED 65 INCHES OF SNOW ON THE GROUND AS OF 7 AM EST
THIS MORNING. SNOW DEPTHS ARE NOW ABOVE NORMAL ACROSS ALL OF MAINE
FOR MID-FEBRUARY.

WATER CONTAINED IN THE MAINE SNOWPACK IS BECOMING VERY IMPRESSIVE.
ALONG THE COAST 3 TO 6 INCHES OF WATER IS HELD IN THE PACK WHILE
FURTHER INLAND...SNOW WATER EQUIVALENTS AVERAGE BETWEEN 6 AND 10
INCHES. HIGHER AMOUNTS TO NEAR A FOOT OF WATER ARE INDICATED ABOVE
2000 FEET IN THE WESTERN AND CENTRAL MAINE HIGHLANDS. MUCH LIKE SNOW
DEPTHS...SNOW WATER EQUIVALENTS ARE ABOVE NORMAL FOR MID-WINTER IN
MAINE.

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

WITH MUCH MORE FREQUENT BOUTS OF RAIN AND SNOW OVER THE PAST FEW
MONTHS...THE LONG TERM DROUGHT ACROSS NEW ENGLAND AND NEW YORK STATE
CONTINUES TO BE DENTED. IN FACT...THE LATEST PALMER DROUGHT SEVERITY
INDEX FROM 11 FEBRUARY 2017 SHOWS ONLY AREAS OF NORTHEAST
VERMONT...SOUTH COASTAL CONNECTICUT AND LONG ISLAND IN MODERATE
DROUGHT CONDITIONS WITH LARGE SWATHS OF CENTRAL AND WESTERN NEW YORK
STATE NOW EXHIBITING UNUSUALLY MOIST CONDITIONS. ACROSS NORTHEAST
VERMONT...THERE IS PLENTY OF SNOW TO MELT OFF THIS SPRING SO WE ARE
REALLY ONLY CURRENTLY CONCERNED FOR AREAS IN SOUTHEAST NEW YORK
STATE...CONNECTICUT AND WESTERN MASSACHUSETTS AS FAR AS ONGOING
DROUGHT IS CONCERNED. THE PALMER DROUGHT SEVERITY INDEX TYPICALLY
LOOKS AT CONDITIONS OVER THE RANGE OF WEEKS TO MONTHS RATHER THAN
DAYS.

TAKING A LOOK AT RESERVOIR LEVELS ACROSS THE REGION...BOTH INDIAN
LAKE AND GREAT SACANDAGA LAKE IN THE ADIRONDACK MOUNTAIN REGION OF
NORTHERN NEW YORK STATE ARE RUNNING ABOUT 2 FEET ABOVE NORMAL
FEBRUARY POOL HEIGHTS WITH HINCKLEY RESERVOIR CLOSER TO 10 FEET
ABOVE NORMAL. SLIGHTLY BELOW NORMAL LAKE LEVELS WERE OBSERVED ON
LAKE CHAMPLAIN ( 0.5 FEET ) AND OWASCO LAKE ( 0.75 FEET ) AS OF 14
FEBRUARY 2017. THE NEW YORK CITY WATER SUPPLY SYSTEM...COMPRISED OF
7 LARGE RESERVOIRS ACROSS SOUTHEAST NEW YORK STATE...WAS AT 78.9
PERCENT OF CAPACITY AS OF 14 FEBRUARY WHICH WAS JUST LESS THAN 10
PERCENT BELOW NORMAL. HOWEVER...THIS IS AN IMPROVEMENT OF MORE THAN
10 PERCENT SINCE LATE DECEMBER 2016 SO THINGS ARE TRENDING IN THE
RIGHT DIRECTION.

ACROSS NEW ENGLAND...MAJOR RESERVOIRS IN BOTH THE KENNEBEC AND
ANDROSCOGGIN RIVER BASINS IN MAINE ARE AT OR ABOVE NORMAL LEVELS. IN
RHODE ISLAND...SCITUATE RESERVOIR...THE MAIN WATER SUPPLY RESERVOIR
FOR NORTHERN RHODE ISLAND INCLUDING THE CITY OF PROVIDENCE...HAS
RISEN TO WITHIN INCHES OF THE SPILLWAY NOW WHICH IS ALSO A DRAMATIC
INCREASE SINCE LATE FALL 2016. IN MASSACHUSETTS...WACHUSETT
RESERVOIR WAS OVER 90 PERCENT FULL AS OF 1 FEBRUARY 2017 BUT QUABBIN
RESERVOIR...WHICH SUPPLIES WATER TO MOST OF METROPOLITAN
BOSTON...STILL HOVERED AT SLIGHTLY BELOW NORMAL LEVELS. THE QUABBIN
RESERVOIR...HOWEVER...HAS A LONG TURN AROUND TIME SO WE WOULD NOT
EXPECT RISING LEVELS FOR ANOTHER MONTH OR TWO.

EXAMINING GROUNDWATER MONITORING WELLS ACROSS NEW ENGLAND AND NEW
YORK STATE COURTESY OF THE UNITED STATES GEOLOGICAL SURVEY ( USGS )
...WE SEE MOST AREAS AT NEAR TO BELOW NORMAL GROUNDWATER LEVELS. THE
EXCEPTIONS ARE FOUND ACROSS CENTRAL AND WESTERN NEW YORK STATE SOUTH
OF THE NEW YORK STATE THRUWAY WHERE LEVELS ARE MOSTLY ABOVE NORMAL
AND ACROSS MOST OF LONG ISLAND WHERE GROUNDWATER LEVELS REMAIN MUCH
BELOW NORMAL. ACROSS NORTHERN NEW YORK STATE AND NORTHERN NEW
ENGLAND...EVEN WHERE GROUNDWATER LEVELS ARE CURRENTLY LOW SUCH AS
WESTERN MAINE AND NORTHERN NEW HAMPSHIRE...WE EXPECT A LOT OF
RECHARGE THIS SPRING DUE TO THE DEEP SNOWPACK SO WE ARE NOT
CURRENTLY CONCERNED. THE ONLY AREAS OF HEIGHTENED AWARENESS CONTINUE
TO BE FOR SOUTHEAST NEW YORK STATE...ESPECIALLY LONG ISLAND...AND
SOUTHWEST NEW ENGLAND WHERE WE NEED ADDITIONAL PRECIPITATION TO
IMPROVE THE GROUNDWATER SYSTEM GOING INTO SPRING OR WE COULD SEE A
RE-INTENSIFICATION OF WATER SUPPLY PROBLEMS.

...RIVER AND ICE CONDITIONS...

ACROSS THE SEVEN STATE REGION OF NEW ENGLAND AND NEW YORK
STATE...RIVER FLOWS REMAIN NEAR TO ABOVE NORMAL EXCEPT ACROSS
PORTIONS OF SOUTHEAST NEW YORK STATE ( ESPECIALLY LONG ISLAND ) AND
SOUTHWEST/SOUTH COASTAL NEW ENGLAND WHERE RIVER FLOWS ARE MOSTLY
BELOW NORMAL. FLOWS ARE HIGHEST ACROSS SOUTHWEST NEW YORK STATE DUE
TO RECENT RAIN AND MELTING SNOW. ACROSS SOUTHWEST NEW YORK
STATE...MANY GAUGED RIVERS AND STREAMS ARE PASSING FLOW WITHIN THE
HIGHEST 10 PERCENT OF THE HISTORICAL RECORD FOR MID-FEBRUARY. IN
CONTRAST...SOME RIVERS AND STREAMS ACROSS LONG ISLAND AND WESTERN
CONNECTICUT ARE PASSING FLOW WITHIN THE LOWEST 10 PERCENT OF THE
HISTORICAL RECORD FOR THE MIDDLE OF FEBRUARY. FOR INSTANCE...THE
FARMINGTON RIVER AT TARIFFVILLE CONNECTICUT HAD A FLOW IN THE LOWEST
7 PERCENT OF THE HISTORICAL RECORD FOR 15 FEBRUARY. THE PERIOD OF
RECORD STRETCHES BACK 43 YEARS.

ACROSS CENTRAL AND SOUTHERN NEW ENGLAND AND FROM THE MOHAWK RIVER
SOUTH AND WEST IN NEW YORK STATE...WHAT RIVER ICE IS IN PLACE IS
THINNER AND WEAKER THAN NORMAL. ACROSS NORTHERN NEW YORK STATE AND
NORTHERN NEW ENGLAND...RIVER ICE IS GENERALLY ESTABLISHED. ICE
THICKNESSES OF 6 TO 12 INCHES ARE COMMON ACROSS NORTHERN NEW YORK
STATE AND NORTHERN VERMONT. FURTHER EAST AND NORTH...RIVER ICE IS
THICKER FROM NORTHERN NEW HAMPSHIRE INTO MOST OF INTERIOR MAINE. IN
THESE AREAS...ICE THICKNESSES OF 1 TO 2 FEET ARE COMMON. FOR
INSTANCE...MEASUREMENTS TAKEN BY THE USGS ON 30 JANUARY 2017 SHOWED
THE ICE TO BE 20 INCHES THICK ALONG THE PISCATAQUIS RIVER AT
BLANCHARD MAINE AND 22 INCHES THICK ON THE BIG BLACK RIVER NEAR
DEPOT MOUNTAIN IN THE NORTHWEST LOGGING WOODS OF MAINE. NOTABLE ICE
JAMS REMAIN IN PLACE ALONG THE KENNEBEC RIVER NEAR AUGUSTA
MAINE...THE MISSISQUOI RIVER AT EAST BERKSHIRE VERMONT AND THE EAST
BRANCH OF THE AU SABLE RIVER NEAR AU SABLE FORKS IN NORTHERN NEW
YORK STATE.

...IN CONCLUSION...

BASED ON THE INFORMATION AVAILABLE AT THIS TIME...THE WINTER/SPRING
FLOOD POTENTIAL IS ABOVE NORMAL ACROSS ALL OF MAINE AND ADJACENT
AREAS OF NORTHERN NEW HAMPSHIRE AND NORTHEAST VERMONT. IN THESE
AREAS...RIVER FLOWS ARE GENERALLY NEAR NORMAL...RESERVOIR LEVELS ARE
NEAR TO ABOVE NORMAL AND LONG TERM ANTECEDENT MOISTURE STATES ARE
CLOSE TO NORMAL. HOWEVER...THE SNOWPACK IS VERY DEEP AND CONTAINS
ABOVE NORMAL AMOUNTS OF WATER WITH SOME MOUNTAINOUS AREAS SEEING
CLOSE TO 12 INCHES OF WATER LOCKED UP IN THE SNOWPACK. THE CONCERN
GOING FORWARD IS THAT THIS SNOWPACK WILL TAKE A LONG TIME TO MELT
OFF...LEAVING THE AREA VULNERABLE TO ANY HEAVY RAINFALL EVENTS AS WE
HEAD INTO SPRING. IT IS IMPORTANT TO NOTE THAT THERE IS NO IMMEDIATE
THREAT FOR FLOODING IN THESE AREAS BUT THE LONGER TERM THREAT IS
ELEVATED.

THE WINTER/SPRING FLOOD POTENTIAL IS SLIGHTLY ABOVE NORMAL ACROSS
THE TUG HILL PLATEAU EAST OF LAKE ONTARIO AND OVER PORTIONS OF THE
SOUTHERN ADIRONDACK MOUNTAINS IN NORTHERN NEW YORK STATE. IN THESE
AREAS...RIVER FLOWS ARE NEAR TO ABOVE NORMAL...RESERVOIRS ARE HIGHER
THAN NORMAL AND ANTECEDENT MOISTURE STATES ARE RISING TO NEAR OR
ABOVE NORMAL. THE SNOWPACK ALSO CONTAINS NEAR TO SOMEWHAT ABOVE
NORMAL WATER EQUIVALENTS DUE TO LAKE EFFECT AND SYNOPTIC SNOW EVENTS
SO FAR THIS WINTER. WITH THE NEAR TERM WEATHER PATTERN FAVORING
WARMER THAN NORMAL TEMPERATURES AND ABOVE NORMAL AMOUNTS OF
PRECIPITATION DURING THE LAST WEEK OF FEBRUARY...THE CONCERN IS THAT
SNOWMELT WILL BEGIN IN EARNEST AND RUNOFF COULD BE ENHANCED BY ANY
LARGE SCALE RAIN EVENT. MEDIUM RANGE NUMERICAL WEATHER MODEL
GUIDANCE IS HINTING AT ONE SUCH POSSIBLE EVENT LATE IN FEBRUARY SO
IT SEEMS FEASIBLE TO HIGHLIGHT THESE AREAS AT A SOMEWHAT HEIGHTENED
RISK FOR FLOODING GOING FORWARD.

THE WINTER/SPRING FLOOD POTENTIAL IS BELOW NORMAL ACROSS PORTIONS OF
SOUTHERN NEW ENGLAND AND SOUTHEAST NEW YORK STATE. IN THESE
AREAS...RIVER FLOWS ARE NEAR TO BELOW NORMAL...GROUNDWATER LEVELS
ARE MOSTLY BELOW NORMAL AND AVAILABLE RESERVOIR STORAGE IS HIGHER
THAN NORMAL...ESPECIALLY ACROSS WESTERN CONNECTICUT AND SOUTHEAST
NEW YORK STATE. AND ALTHOUGH THERE IS SOME SNOW ON THE GROUND...THE
AMOUNT OF WATER IN THE PACK AVAILABLE FOR MELT RUNOFF IS NOT TOO
SIGNIFICANT...GENERALLY BETWEEN 1 AND 2 INCHES. MOST OF THIS WILL
MELT OFF OVER THE NEXT 10 DAYS...LEAVING MAINLY BARE GROUND AS WE
HEAD INTO LATE FEBRUARY. THE THINKING IS THAT THE LOW RESERVOIR
LEVELS AND LOW GROUNDWATER LEVELS WILL GIVE THESE AREAS SOME WIGGLE
ROOM TO HANDLE AN ORDINARY HEAVY RAINFALL EVENT WITHOUT MUCH FANFARE
HENCE JUSTIFYING A SOMEWHAT BELOW NORMAL THREAT FOR FLOODING AS WE
HEAD TOWARDS SPRING.

ACROSS THE REMAINDER OF THE NERFC SERVICE AREA...THE WINTER/SPRING
FLOOD POTENTIAL IS GENERALLY NEAR NORMAL. FOR MOST OF CENTRAL AND
WESTERN NEW ENGLAND AND CENTRAL/NORTHERN NEW YORK STATE...THE AMOUNT
OF SNOW ON THE GROUND LEAVES THE REGION AT A NEAR NORMAL RISK FOR
RAIN/SNOWMELT FLOODING HEADING TOWARDS SPRING. IN WESTERN NEW YORK
STATE...THE NEAR NORMAL THREAT COMES FROM THE VERY WET ANTECEDENT
MOISTURE CONDITIONS AND HIGH RIVER FLOWS WHICH OFFSETS THE LACK OF
SNOW WATER AVAILABLE FOR MELT RUNOFF.

THE POTENTIAL FOR FLOODING DUE TO ICE JAMS IS NEAR TO SLIGHTLY ABOVE
NORMAL ACROSS NORTHERN NEW YORK STATE...NORTHERN VERMONT...NORTHERN
NEW HAMPSHIRE AND ALL OF INTERIOR MAINE. ACROSS THE TUG HILL PLATEAU
AND SOUTHERN ADIRONDACK MOUNTAIN REGIONS IN NEW YORK STATE...THIS
THREAT IS IN THE NEAR TERM AS SNOWMELT AND POSSIBLE RAINFALL
INCREASES FLOW OVER THE NEXT FEW WEEKS. THERE COULD BE ENOUGH FLOW
INCREASE IF A RAIN EVENT DEVELOPS TO CAUSE ICE TO BREAK AND MOVE
LEADING TO ICE JAM ISSUES DURING THE LAST WEEK OF FEBRUARY.
THEREFORE...THE RISK FOR ICE JAM FLOODING IS SOMEWHAT HEIGHTENED IN
THE NEAR TERM FOR THESE AREAS.

FURTHER NORTH...THE ICE IS THICKER ACROSS THE NORTHERN
ADIRONDACKS...NORTHERN VERMONT...NORTHERN NEW HAMPSHIRE AND INTERIOR
MAINE. IN FACT...MOST RIVERS FROM NORTHERN NEW HAMPSHIRE INTO
WESTERN/NORTHERN MAINE ARE CLOGGED WITH ICE 1-2 FEET THICK. IT IS
UNLIKELY THIS ICE WILL MOVE BEFORE THE BEGINNING OF MARCH BUT GOING
FORWARD INTO MARCH...THERE IS STILL PLENTY OF POTENTIAL FOR ICE JAM
FLOODING IF SNOWMELT AND RAINFALL BOOST RIVER FLOWS QUICKLY.
THEREFORE...THE THREAT IS DEEMED TO BE NEAR TO SLIGHTLY ABOVE NORMAL
IN THESE AREAS. POTENTIAL PROBLEM SPOTS FOR JAMS ARE THE KENNEBEC
RIVER NEAR AUGUSTA MAINE...THE MISSISQUOI RIVER NEAR EAST BERKSHIRE
VERMONT AND THE EAST BRANCH OF THE AU SABLE RIVER NEAR AU SABLE
FORKS IN NORTHERN NEW YORK STATE.

THE POTENTIAL FOR FLOODING DUE TO ICE JAMS IS BELOW NORMAL TO NON-
EXISTENT FROM THE MOHAWK RIVER SOUTH AND WEST IN NEW YORK STATE AND
ACROSS MOST OF CENTRAL AND ALL OF SOUTHERN NEW ENGLAND. IN THESE
AREAS...THE ICE IN AREA RIVERS AND STREAMS IS THINNER THAN NORMAL.
IN ADDITION...WITH WARM TEMPERATURES FORECAST OVER THE NEXT FEW
WEEKS...THE THOUGHT IS THAT MOST OF THIS ICE WILL ROT AND GRADUALLY
DISSIPATE. IF RIVER FLOWS INCREASE RAPIDLY...MOST OF THIS ICE IS
THOUGHT TO BE TOO WEAK TO HOLD BACK SIGNIFICANT AMOUNTS OF WATER AND
WOULD MORE LIKELY BUCKLE AND FLUSH OUT QUITE RAPIDLY. ALL THIS
POINTS TO A SOMEWHAT BELOW NORMAL RISK FOR ICE JAM FLOODING OVER THE
NEXT FEW WEEKS. IN FACT...ACROSS COASTAL SOUTHERN NEW ENGLAND AND
FAR SOUTHEAST NEW YORK STATE...IT IS HIGHLY UNLIKELY RIVER ICE WILL
REFORM TO ANY APPRECIABLE EXTENT FOR THE REMAINDER OF THIS SEASON
MAKING THE THREAT FOR ICE JAM FLOODING PRETTY MUCH NON-EXISTENT.

IT IS IMPORTANT TO REMEMBER THAT VERY HEAVY RAINFALL CAN RESULT IN
FLOODING AT ANY TIME OF YEAR...EVEN IN AREAS THAT HAVE LITTLE OR NO
SNOW ON THE GROUND.

A GRAPHIC DEPICTING THE FLOOD POTENTIAL ON A BASIN BY BASIN BASIS IS
AVAILABLE ON THE NERFC WEB SITE AT


        ***WWW.WEATHER.GOV/IMAGES/NERFC/OPS/FP1_TODAY.JPG***

ALL IN LOWER CASE.

THE NEXT WINTER/SPRING FLOOD POTENTIAL OUTLOOK WILL BE ISSUED BY
THE NERFC ON THURSDAY 2 MARCH 2017.

END/HORWOOD
$$



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