Extended Streamflow Guidance
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WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE
NORTHEAST RIVER FORECAST CENTER TAUNTON MA
600 PM EST WED FEB 14 2018

...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 ACROSS MOST OF WESTERN AND NORTHERN NEW YORK STATE
EXTENDING INTO LARGE PORTIONS OF VERMONT. THE WINTER/SPRING FLOOD
POTENTIAL IS ALSO ABOVE NORMAL ACROSS SOME COASTAL SOUTHERN NEW
ENGLAND RIVERS DUE TO CURRENT NEAR FLOOD FLOWS.

ELSEWHERE ACROSS NEW ENGLAND AND NEW YORK STATE...THE WINTER/SPRING
FLOOD POTENTIAL IS NEAR NORMAL EXCEPT BELOW NORMAL ACROSS FAR
SOUTHEAST PORTIONS OF NEW YORK STATE.

THE POTENTIAL FOR FLOODING DUE TO ICE JAMS CONTINUES ABOVE NORMAL
ACROSS ALL OF NORTHERN NEW ENGLAND AND IN NEW YORK STATE FROM THE
MOHAWK RIVER NORTHWARD. ELSEWHERE...ACROSS MOST OF SOUTHERN NEW
ENGLAND AND SOUTHERN/WESTERN NEW YORK STATE...THE POTENTIAL FOR
FLOODING DUE TO ICE JAMS IS NEAR OR BELOW NORMAL NOW.

...CLIMATE GUIDANCE...

THE SEVEN STATE REGION OF NEW ENGLAND AND NEW YORK STATE HAS BEEN
LOCATED VERY CLOSE TO THE MAIN STORM TRACK OVER THE PAST FEW WEEKS
WITH SEVERAL SYSTEMS AFFECTING THE REGION. THESE SYSTEMS HAVE ADDED
TO THE SNOWPACK ACROSS NORTHERN NEW ENGLAND AND WESTERN/NORTHERN NEW
YORK STATE BUT BROUGHT MAINLY RAINFALL TO SOUTHERN NEW ENGLAND AND
SOUTHEAST NEW YORK STATE.

OVER THE NEXT WEEK TO 10 DAYS...WE ARE SEEING STRONG SIGNALS FOR A
POSITIVE NORTH ATLANTIC OSCILLATION ( NAO ) PATTERN AND A NEUTRAL TO
NEGATIVE PACIFIC NORTH AMERICA ( PNA ) PATTERN. WITH A POSITIVE NAO
PATTERN...COLD AIR THAT ENTERS THE NORTHEASTERN UNITED STATES
TYPICALLY IS TRANSITORY AND MOVES EAST RAPIDLY. AND WITH A NEUTRAL
TO NEGATIVE PNA PATTERN...UPPER LEVEL RIDGING IS FAVORED ACROSS THE
SOUTHEASTERN UNITED STATES. IF THIS PATTERN HOLDS...THE NET RESULT
WILL BE A SHIFT WEST IN THE STORM TRACK...BRINGING MILD AIR TO MUCH
OF NEW ENGLAND AND NEW YORK STATE. THE SHIFT IN THE STORM TRACK WEST
WOULD FAVOR HEAVIER PRECIPITATION MIGRATING INLAND FROM THE COAST
TOWARDS THE GREAT LAKES. SO...APART FROM A QUICK HITTING SNOW EVENT
ACROSS NEW ENGLAND THIS UPCOMING WEEKEND...WE ARE FAIRLY CONFIDENT
IN A WARMER AND WETTER THAN NORMAL PATTERN GOING INTO LATE FEBRUARY.

THE OFFICIAL NATIONAL WEATHER SERVICE 8 TO 14 DAY OUTLOOK FOR 21-27
FEBRUARY 2018 ECHOES THE ABOVE THOUGHTS AS IT CALLS FOR TEMPERATURES
TO AVERAGE ABOVE NORMAL ACROSS ALL OF NEW ENGLAND AND NEW YORK STATE
WITH PRECIPITATION ALSO AVERAGING ABOVE NORMAL ACROSS THE ENTIRE
NERFC SERVICE AREA. WE ARE MOST CONFIDENT IN WARM AND WET CONDITIONS
ACROSS WESTERN NEW YORK STATE.

THERE ARE SOME SUBTLE SIGNS IN THE MEDIUM RANGE CLIMATE GUIDANCE
INDICATING A COLDER REGIME COULD TAKE HOLD IN EARLY MARCH AS THE NAO
ATTEMPTS TO GO NEGATIVE WHICH REALLY HAS NOT HAPPENED SINCE NOVEMBER
OF 2017.

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

OVER THE PAST TWO WEEK PERIOD...SNOW DEPTHS AND WATER EQUIVALENTS
HAVE INCREASED ACROSS NORTHERN NEW ENGLAND AND WESTERN/NORTHERN NEW
YORK STATE AND DECREASED ACROSS SOUTHERN NEW ENGLAND AND SOUTHEAST
NEW YORK STATE. SNOW DEPTHS ARE CLOSE TO OR A LITTLE ABOVE NORMAL
ACROSS NORTHERN MAINE BUT REMAIN NEAR TO IN SOME CASES MUCH BELOW
NORMAL ELSEWHERE FOR MID-FEBRUARY.

...NEW YORK STATE...

SOUTH AND WEST OF THE MOHAWK RIVER IN NEW YORK STATE...SNOW DEPTHS
CONTINUE TO AVERAGE MOSTLY BELOW 10 INCHES WITH BARE GROUND ACROSS
SOUTHEAST NEW YORK STATE INCLUDING LONG ISLAND. THERE ARE SOME 10 TO
15 INCH SNOW DEPTHS IN THE LAKE EFFECT SNOWBELT SOUTH OF BUFFALO
HOWEVER. NORTH OF THE MOHAWK RIVER...SNOW DEPTHS INCREASE ACROSS THE
ADIRONDACK MOUNTAIN CHAIN AND TUG HILL PLATEAU EAST OF LAKE ONTARIO.
IN THESE AREAS...SNOW DEPTHS BETWEEN 1 AND 2 FEET ARE THE NORM BUT
DO INCREASE TO NEAR 3 FEET IN THE HIGHER RIDGES OF THE TUG HILL
PLATEAU AND ABOVE 2500 FEET IN THE ADIRONDACKS. NEW YORK STATE
MESONET WEBCAMS SHOWED NEAR 3 FEET OF SNOW ON THE GROUND IN REDFIELD
ON THE TUG HILL PLATEAU AT AN ELEVATION OF 1250 FEET THIS MORNING.
ACROSS THE SAINT LAWRENCE RIVER VALLEY BORDERING NORTHERN NEW YORK
STATE AND CANADA...SNOW DEPTHS AVERAGE BETWEEN 6 AND 12 INCHES. SNOW
DEPTHS ACROSS NEW YORK STATE ARE NEAR TO BELOW NORMAL FOR MID-
FEBRUARY AND ARE ESPECIALLY BELOW NORMAL ACROSS THE CATSKILL
MOUNTAIN RANGE IN SOUTHEAST NEW YORK STATE.

ALONG AND SOUTH OF THE MOHAWK RIVER IN NEW YORK STATE...SNOW WATER
EQUIVALENTS RANGE FROM NOTHING IN SOUTHEAST NEW YORK STATE TO AS
HIGH AS AROUND 2 INCHES. THERE ARE SOME LOCALLY HIGHER AMOUNTS
ACROSS THE LAKE EFFECT SNOWBELT SOUTH OF BUFFALO IN WESTERN NEW YORK
STATE WHERE AMOUNTS BETWEEN 2 AND 4 INCHES ARE BEING REPORTED. 3.9
INCHES OF WATER WAS OBSERVED IN THE 13 INCH SNOWPACK IN FOOTES AS OF
13 FEBRUARY. NORTH OF THE MOHAWK RIVER IN NEW YORK STATE...SNOW
WATER EQUIVALENTS BETWEEN 2 AND 4 INCHES ARE COMMON IN THE VALLEYS
OF THE ADIRONDACK MOUNTAIN CHAIN AND TUG HILL PLATEAU...INCREASING
TO BETWEEN 4 AND 8 INCHES IN THE HIGHER TERRAIN. AN OBSERVER IN
BOONVILLE ON THE EDGE OF THE TUG HILL PLATEAU REPORTED 6.9 INCHES OF
WATER IN THE SNOWPACK AS OF YESTERDAY. FURTHER NORTH IN NEW YORK
STATE...SNOW WATER EQUIVALENTS DECREASE TO BETWEEN 1 AND 3 INCHES
ACROSS THE SAINT LAWRENCE VALLEY BORDERING CANADA. SNOW WATER
EQUIVALENTS ARE NEAR TO BELOW NORMAL ACROSS NEW YORK STATE FOR THE
DEAD OF WINTER.

...SOUTHERN NEW ENGLAND...

THE ONLY SNOW IN SOUTHERN NEW ENGLAND IS FOUND ACROSS NORTH CENTRAL
AND WESTERN MASSACHUSETTS AND FAR NORTHWEST CONNECTICUT AND EVEN
THERE...SNOW DEPTHS ARE MOSTLY UNDER 6 INCHES. ONLY IN THE HIGHEST
TERRAIN OF THE BERKSHIRE MOUNTAINS IN WESTERN MASSACHUSETTS ARE SNOW
DEPTHS NEAR A FOOT. WATER EQUIVALENTS IN THIS SPARSE SNOWPACK ARE
RUNNING LESS THAN AN INCH EXCEPT ACROSS THE HIGHEST TERRAIN IN THE
BERKSHIRE MOUNTAINS OF WESTERN MASSACHUSETTS WHERE WATER EQUIVALENTS
ARE AT MOST 1 TO 3 INCHES.

...VERMONT...

BELOW ABOUT 1000 FEET IN SOUTHERN AND WESTERN VERMONT TO INCLUDE THE
CHAMPLAIN VALLEY...SNOW DEPTHS AVERAGE BETWEEN 6 AND 12 INCHES.
ACROSS THE REMAINDER OF VERMONT...SNOW DEPTHS OF 1 TO 2 FEET ARE THE
NORM WITH SPOT HIGHER AMOUNTS ABOVE 2000 FEET AND IN THE NORTHEAST
KINGDOM. 30 INCHES OF SNOW WAS OBSERVED IN GRANBY IN THE NORTHEAST
KINGDOM OF VERMONT AS OF TUESDAY 13 FEBRUARY 2018. SNOW DEPTHS
ACROSS THE STATE OF VERMONT ARE NEAR TO BELOW NORMAL STATEWIDE.

BELOW ABOUT 1000 FEET IN SOUTHERN AND WESTERN VERMONT TO INCLUDE THE
CHAMPLAIN VALLEY...SNOW WATER EQUIVALENTS AVERAGE BETWEEN 1 AND 3
INCHES. THOSE AMOUNTS INCREASE TO BETWEEN 3 AND 6 INCHES ACROSS THE
REMAINDER OF THE STATE WITH LOCALIZED AMOUNTS TO 7 OR 8 INCHES IN
THE HIGHEST TERRAIN OF NORTHERN AND ESPECIALLY NORTHEAST VERMONT.
SNOW WATER EQUIVALENTS ARE NEAR TO BELOW NORMAL ACROSS VERMONT FOR
MID-FEBRUARY.

...NEW HAMPSHIRE...

ACROSS SOUTHERN NEW HAMPSHIRE...SNOW DEPTHS RANGE FROM A TRACE TO AS
MUCH AS 10 TO 15 INCHES AROUND 1000 FEET. ACROSS CENTRAL AND
NORTHERN NEW HAMPSHIRE...SNOW DEPTHS OF 1 TO 2 FEET ARE THE NORM
WITH LOWER AMOUNTS AROUND LAKE WINNIPESAUKEE AND HIGHER AMOUNTS
ABOVE 2000 FEET IN THE WHITE MOUNTAINS. SNOW DEPTHS ARE NEAR TO
BELOW NORMAL ACROSS NEW HAMPSHIRE FOR MID-FEBRUARY.

ACROSS SOUTHERN NEW HAMPSHIRE...SNOW WATER EQUIVALENTS RANGE FROM
JUST A TRACE NEAR THE COAST TO AS HIGH AS 3 OR 4 INCHES AROUND 1000
FEET. SNOW WATER EQUIVALENTS INCREASE ACROSS CENTRAL AND NORTHERN
NEW HAMPSHIRE WHERE...ON AVERAGE...3 TO 6 INCHES OF WATER IS
AVAILABLE IN THE SNOWPACK FOR RUNOFF. LOCALLY HIGHER AMOUNTS BETWEEN
5 AND 10 INCHES ARE FOUND ACROSS THE HIGHEST ELEVATIONS OF NORTHERN
NEW HAMPSHIRE...ESPECIALLY IN THE WHITE MOUNTAIN NATIONAL FOREST.
SNOW WATER EQUIVALENTS ACROSS THE GRANITE STATE REMAIN NEAR TO BELOW
NORMAL FOR THIS TIME OF YEAR.

...MAINE...

SNOW CONTINUES TO BLANKET THE ENTIRE STATE OF MAINE AS OF THIS
MORNING. WITHIN ABOUT 20 OR 30 MILES OF THE COAST IN MAINE...SNOW
DEPTHS AVERAGE NEAR OR LESS THAN A FOOT WITH LOCALLY HIGHER AMOUNTS.
SNOW DEPTHS ACROSS THE REST OF MAINE AVERAGE BETWEEN 1 AND 2.5 FEET
ALTHOUGH SOME AMOUNTS NEAR 3 FEET ARE BEING REPORTED IN NORTHERN
MAINE. CARIBOU REPORTED 33 INCHES OF SNOW ON THE GROUND AS OF THIS
MORNING. SNOW DEPTHS IN MAINE ARE NEAR NORMAL UP NORTH AND NEAR TO A
BIT BELOW NORMAL IN THE SOUTH FOR MID-FEBRUARY.

WITHIN 20 OR 30 MILES OF THE COAST IN MAINE...SNOW WATER EQUIVALENTS
AVERAGE BETWEEN 1 AND 4 INCHES. ACROSS THE REMAINDER OF THE STATE OF
MAINE...3 TO 6 INCHES OF MELTWATER IS COMMON IN THE PACK WITH HIGHER
AMOUNTS TO 7 OR 8 INCHES RESERVED FOR THE HIGHER ELEVATIONS IN THE
WESTERN/CENTRAL MAINE HIGHLANDS AS WELL AS ACROSS FAR NORTHERN
MAINE. RUSSELL POND...IN THE HEADWATERS OF THE PENOBSCOT RIVER
ACROSS NORTHWEST MAINE...REPORTED 6.8 INCHES OF WATER IN THE 35 INCH
SNOWPACK AS OF 9 FEBRUARY 2018 AND CARIBOU...IN NORTHEAST
MAINE...REPORTED AN EVEN 8 INCHES OF WATER HELD IN THEIR 33 INCH
SNOWPACK AS OF TODAY. SNOW WATER EQUIVALENTS ARE NEAR NORMAL ACROSS
NORTHERN MAINE AND NEAR TO BELOW NORMAL ACROSS MOST OF THE REST OF
MAINE FOR THIS TIME IN WINTER.

...SOIL MOISTURE AND GROUNDWATER CONDITIONS...

THE VERY ACTIVE WEATHER PATTERN OVER THE PAST FEW WEEKS HAS KEPT
MOISTURE STATES HIGH AS SEVERAL SYSTEMS HAVE DROPPED MODERATE TO
HEAVY AMOUNTS OF RAIN AND SNOW ACROSS NEW ENGLAND AND NEW YORK
STATE. THE LATEST PALMER DROUGHT SEVERITY INDEX FROM 10 FEBRUARY
2018 SHOWED ALL OF NEW ENGLAND AND NEW YORK STATE AT OR ABOVE NORMAL
IN TERMS OF ANTECEDENT MOISTURE STATES. THE WETTEST CONDITIONS ARE
SHOWN ACROSS WESTERN AND NORTHERN NEW YORK STATE WHERE VERY TO
EXTREMELY MOIST CONDITIONS ARE BEING OBSERVED. THE PALMER INDEX
LOOKS AT MOISTURE STATES SPANNING WEEKS TO MONTHS. NEAR SURFACE SOIL
MOISTURE ANOMALY MAPS FROM 12 FEBRUARY 2018 ALSO SHOW HIGH MOISTURE
STATES ACROSS WESTERN NEW YORK STATE AND ALL OF EASTERN NEW ENGLAND
WITH THE ONLY DRYNESS ACROSS EAST CENTRAL AND SOUTHEAST NEW YORK
STATE.

DROUGHT IS NOT REALLY A FACTOR ACROSS THE NERFC SERVICE AREA AS WE
HEAD INTO LATE WINTER. THE LATEST U.S. DROUGHT MONITOR SHOWS A FEW
PATCHES OF ABNORMALLY DRY CONDITIONS ACROSS SOUTHEAST NEW YORK STATE
AND SINCE THAT AREA HAS LITTLE TO NO SNOW...IT COULD BEAR WATCHING
IF A DRY SPELL DEVELOPS HEADING INTO SPRING.

TAKING A LOOK AT GROUNDWATER MONITORING WELLS ACROSS NEW YORK STATE
AND NEW ENGLAND COURTESY OF THE UNITED STATES GEOLOGICAL SURVEY
(USGS)...MOST ALL AREAS ARE REPORTING NEAR TO ABOVE NORMAL LEVELS.
GROUNDWATER LEVELS ARE HIGHEST ACROSS DOWNEAST MAINE DUE TO HEAVY
RAINFALL AND SNOWMELT THAT HAS CONTINUED SINCE MID-JANUARY.
MONITORING WELLS AT AMHERST...BAR HARBOR AND HADLEY LAKES WERE ALL
AT RECORD HIGH FEBRUARY GROUNDWATER LEVELS AND SOME OF THESE WELLS
HAVE RECORDS GOING BACK MORE THAN 30 YEARS. THE ONLY AREA WHERE
GROUNDWATER IS BELOW NORMAL STRETCHES FROM THE LOWER HUDSON VALLEY
IN SOUTHEAST NEW YORK STATE SOUTHEAST INTO LONG ISLAND. MOST
MONITORING WELLS IN THESE AREAS ARE REPORTING BELOW TO MUCH BELOW
NORMAL LEVELS. SOME OF THE DEEP AQUIFER WELLS ACROSS LONG ISLAND
WERE APPROACHING RECORD LOW LEVELS FOR FEBRUARY SO THIS WILL BE AN
AREA TO WATCH GOING FORWARD IF WE DON`T SEE NORMAL AMOUNTS OF
PRECIPITATION HEADING INTO SPRING.

...RESERVOIR LEVELS...

RESERVOIR LEVELS ARE FAIRLY HIGH ACROSS NORTHERN NEW YORK STATE AND
MUCH OF NORTHERN NEW ENGLAND FOR FEBRUARY. IN NORTHERN NEW YORK
STATE...INDIAN LAKE WAS RUNNING ABOUT 3 FEET HIGHER THAN ITS NORMAL
POOL LEVEL AND GREAT SACANDAGA LAKE WAS EVEN HIGHER...ABOUT 4 FEET
HIGHER THAN NORMAL. MOST OF THIS RESULTED FROM INCREASED STORAGE
DURING THE LARGE THAW IN MID-JANUARY. LAKE CHAMPLAIN IS MUCH CLOSER
TO NORMAL FEBRUARY LEVELS AFTER RECEDING SOME OVER THE PAST 2 WEEKS.
IN NORTHERN NEW ENGLAND...RESERVOIRS IN THE ANDROSCOGGIN RIVER BASIN
DRAINING PORTIONS OF NORTHERN NEW HAMPSHIRE AND WESTERN MAINE WERE
61 PERCENT FULL WHICH IS 16 PERCENT ABOVE NORMAL. RESERVOIR LEVELS
IN THE KENNEBEC RIVER BASIN IN MAINE ARE ALSO A BIT ABOVE NORMAL.

FURTHER SOUTH...MOST LARGE SCALE WATER SUPPLY RESERVOIRS WERE IN THE
NORMAL TO ABOVE NORMAL RANGE AS WELL. THE NEW YORK CITY WATER SUPPLY
SYSTEM...COMPRISED OF 7 LARGE RESERVOIRS IN SOUTHEAST NEW YORK
STATE...WAS RUNNING AT 86.5 PERCENT CAPACITY WHICH WAS ABOUT 2
PERCENT BELOW NORMAL AS OF 12 FEBRUARY 2018. IN SOUTHERN NEW
ENGLAND...QUABBIN RESERVOIR...THE MAIN WATER SUPPLY RESERVOIR FOR
GREATER BOSTON...CONTINUED TO BE IN ITS NORMAL OPERATING RANGE WHILE
IN RHODE ISLAND...SCITUATE RESERVOIR...THE MAJOR SUPPLIER OF WATER
TO NORTHERN RHODE ISLAND INCLUDING THE CITY OF PROVIDENCE...WAS AT
105 PERCENT CAPACITY AND SPILLING UNCONTROLLED WATER INTO THE
PAWTUXET RIVER. SO IN SUMMARY...NO WIDESPREAD WATER SUPPLY PROBLEMS
ARE CURRENTLY ANTICIPATED AS WE HEAD TOWARD SPRING ALTHOUGH WE ARE
BEGINNING TO BECOME A BIT MORE CONCERNED FOR DRYNESS ACROSS
SOUTHEAST NEW YORK STATE...ESPECIALLY LONG ISLAND.

...RIVER AND ICE CONDITIONS...

RIVER FLOWS ACROSS THE SEVEN STATE REGION OF NEW ENGLAND AND NEW
YORK STATE ARE RUNNING MOSTLY ABOVE NORMAL FOR MID-FEBRUARY. FLOWS
ARE HIGHEST ACROSS SOUTHERN AND EASTERN NEW ENGLAND WHERE MANY
GAUGED RIVERS AND STREAMS WERE PASSING FLOWS IN THE HIGHEST 10
PERCENT OF THE HISTORICAL RECORD FOR 14 FEBRUARY. IN RHODE
ISLAND...THE PAWCATUCK RIVER AT WESTERLY WAS WITHIN A HALF FOOT OF
ITS 7 FOOT FLOOD STAGE TODAY...SETTING A NEW RECORD HIGH FLOW FOR 14
FEBRUARY. RECORDS FOR WESTERLY GO BACK 76 YEARS. RIVER FLOWS ARE
CLOSEST TO NORMAL ACROSS INTERIOR NEW YORK STATE AND ALSO ON LONG
ISLAND.

RIVER ICE REMAINS AN EXTREME CONCERN ACROSS NORTHERN PORTIONS OF NEW
YORK STATE AND CENTRAL/NORTHERN NEW ENGLAND ALTHOUGH RIVER ICE
CONDITIONS HAVE IMPROVED DRAMATICALLY ACROSS MOST OF SOUTHERN NEW
ENGLAND AND SOUTHERN/WESTERN PORTIONS OF NEW YORK STATE SINCE MID-
JANUARY.

THE MASSIVE MELT...HEAVY RAINFALL AND WARM TEMPERATURES DURING MID
JANUARY WERE ABLE TO BREAK AND MOVE ICE ACROSS MOST ALL OF NEW YORK
STATE AND NEW ENGLAND WITH THE EXCEPTION OF NORTHERN MAINE WHERE
MOST OF THE ICE HAS REMAINED INTACT. MANY OF THE ICE JAMS THAT
DEVELOPED IN MID-JANUARY REMAIN LOCKED IN PLACE. ICE THICKNESSES
HAVE INCREASED ACROSS NORTHERN MAINE OVER THE PAST 2 WEEKS WITH
THICKNESSES OF BETWEEN 18 AND 24 INCHES NOW COMMON ACROSS THE SAINT
JOHN...FISH AND AROOSTOOK RIVERS WITH EVEN SOME 30 INCH THICKNESSES
MEASURED ALONG THE SEBOIS RIVER IN NORTHERN PENOBSCOT COUNTY.
ELSEWHERE ACROSS NORTHERN NEW ENGLAND AND NORTHERN NEW YORK
STATE...10 TO 20 INCH THICKNESSES ARE QUITE COMMON.

THE ICE JAMS REMAIN TOO NUMEROUS TO COUNT HOWEVER...THE MOST SERIOUS
SITUATIONS INCLUDE...

IN NEW YORK STATE...A 17 MILE LONG ICE JAM EXISTS ON THE MOHAWK
RIVER FROM EAST OF SCHENECTADY WEST TO ABOUT GLENVILLE. ICE JAMS
ALSO REMAIN IN PLACE ALONG THE UPPER HUDSON RIVER AS WELL.

IN VERMONT...SIGNIFICANT ICE JAMS REMAIN IN PLACE ALONG THE
MISSISQUOI...WINOOSKI AND LAMOILLE RIVERS.

IN MAINE...A PERSISTENT ICE JAM REMAINS IN PLACE ON THE MAINSTEM
KENNEBEC RIVER AT AUGUSTA. ICE JAMS ARE ALSO BEING REPORTED IN
BANGOR ON THE KENDUSKEAG STREAM AND ALONG THE MAINSTEM PENOBSCOT
RIVER BETWEEN BANGOR AND EDDINGTON.

IN NEW HAMPSHIRE...AN ICE JAM IS IN PLACE ON THE SOUTH BRANCH OF THE
PISCATAQUOG RIVER IN NEW BOSTON.

ALSO IN NEW HAMPSHIRE...AN ICE JAM REMAINS IN PLACE ON THE
PEMIGEWASSET RIVER JUST DOWNSTREAM OF THE RIVER GAUGE AT PLYMOUTH.

IN CONNECTICUT...AN ICE JAM REMAINS IN PLACE ALONG THE HOUSATONIC
RIVER NEAR THE TOWN OF KENT AND HAS CONTINUED TO CAUSE SPORADIC
FLOODING AS RECENTLY AS THIS PAST WEEKEND.

THESE ICE JAMS REMAIN A SERIOUS SITUATION GOING FORWARD TOWARD THE
BREAKUP SEASON AND WE COULD SEE SOME ICE MOVEMENT...ESPECIALLY
ACROSS NEW YORK STATE...VERMONT AND PORTIONS OF NEW HAMPSHIRE OVER
THE NEXT 2 WEEKS. IN MAINE...WE CURRENTLY BELIEVE MOST OF THE ICE
WILL REMAIN IN PLACE INTO MARCH WITHOUT RUNNING.

...IN CONCLUSION...

BASED ON THE INFORMATION AVAILABLE AT THIS TIME...THE WINTER/SPRING
FLOOD POTENTIAL IS ABOVE NORMAL ACROSS WESTERN AND NORTHERN PORTIONS
OF NEW YORK STATE EXTENDING INTO MUCH OF VERMONT. IN THESE
AREAS...RIVER FLOWS ARE AT OR ABOVE NORMAL AND ANTECEDENT MOISTURE
STATES ARE WET. AND WITH FAIRLY HIGH CONFIDENCE FOR A SIGNIFICANT
WARMUP WITH RAIN NEXT WEEK ACROSS THESE AREAS...SNOW WILL BE
MELTING...INCREASING RIVER FLOWS. THE DETERMINING FACTOR FOR
FLOODING WILL BE THE AMOUNT OF RAINFALL THAT OCCURS BUT NEEDLESS TO
SAY...THESE PARAMETERS CERTAINLY POINT TO A HIGHER THAN NORMAL FLOOD
POTENTIAL THROUGH LATE FEBRUARY. WITHIN THESE AREAS...WE FEEL THE
FLOOD POTENTIAL IS HIGHEST ACROSS THE STREAMS AND CREEKS NEAR
BUFFALO...OVER THE TUG HILL PLATEAU AND IN THE ADIRONDACK MOUNTAIN
AREAS OF NEW YORK STATE.

THE WINTER/SPRING FLOOD POTENTIAL IS ALSO ABOVE NORMAL IN THE NEAR
TERM ACROSS COASTAL SOUTHEASTERN NEW ENGLAND. IN THIS
AREA...ALTHOUGH THERE IS NO SNOW ON THE GROUND FOR MELT
RUNOFF...RIVER FLOWS ARE MUCH ABOVE NORMAL AND ANTECEDENT MOISTURE
STATES ARE WET. FOR INSTANCE...THE PAWCATUCK RIVER AT WESTERLY RHODE
ISLAND CONTINUED TO HOVER WITHIN HALF A FOOT OF FLOOD STAGE THIS
MORNING WITH OTHER RIVERS AND STREAMS ALSO RUNNING HIGH. WITH SOME
SNOW THIS WEEKEND AND RAIN/WARM TEMPERATURES IN THE FORECAST NEXT
WEEK...IT WILL NOT TAKE A TREMENDOUS AMOUNT OF RAIN TO FORCE SOME OF
THESE RIVERS INTO FLOOD. FOR THAT REASON...AN ABOVE NORMAL THREAT
FOR FLOODING IS DEEMED TO EXIST ACROSS COASTAL SOUTHEAST NEW ENGLAND.

THE WINTER/SPRING FLOOD POTENTIAL IS NEAR NORMAL ACROSS MAINE...NEW
HAMPSHIRE AND PORTIONS OF EASTERN/SOUTHERN VERMONT. IN THESE
AREAS...RIVER FLOWS ARE NEAR TO ABOVE NORMAL...SNOW DEPTHS ARE NEAR
TO BELOW NORMAL AND ANTECEDENT MOISTURE STATES CONTINUE AT OR ABOVE
NORMAL. UNLIKE AREAS FURTHER TO THE WEST IN WESTERN VERMONT AND
NORTHERN NEW YORK STATE WHERE WE ARE CONFIDENT IN A SIGNIFICANT
WARMUP WITH RAINFALL NEXT WEEK...THERE ARE MIXED SIGNALS REGARDING
JUST HOW MUCH WARM AIR AND RAINFALL ACTUALLY GETS EAST OF THE GREEN
MOUNTAINS INTO NORTHERN NEW ENGLAND. FOR THIS REASON...IT SEEMS A
NORMAL FLOOD THREAT IS A REASONABLE ASSUMPTION GOING FORWARD INTO
LATE FEBRUARY AND MARCH. FURTHER SOUTH AND WEST ACROSS WESTERN
PORTIONS OF SOUTHERN NEW ENGLAND AND EAST CENTRAL NEW YORK
STATE...ABOVE NORMAL RIVER FLOWS ARE COUNTERBALANCED BY LITTLE TO NO
SNOW...ALSO RESULTING IN A NEAR NORMAL POTENTIAL FOR FLOODING GOING
FORWARD.

THE WINTER/SPRING FLOOD POTENTIAL IS BELOW NORMAL ACROSS A SMALL
AREA OF SOUTHEAST NEW YORK STATE TO INCLUDE THE WALLKILL
RIVER...RONDOUT CREEK AND LOWER HUDSON RIVER BASIN. IN THESE
AREAS...RIVER FLOWS ARE NEAR TO A BIT ABOVE NORMAL HOWEVER THERE IS
NO SNOW ON THE GROUND...GROUNDWATER LEVELS ARE NEAR TO BELOW NORMAL
AND NEAR SURFACE SOIL MOISTURE IS LACKING. WE WOULD NEED TO SEE A
VERY HEAVY RAINFALL EVENT...POSSIBLY MORE THAN ONE...IN ORDER TO
BRING A SIGNIFICANT RISK OF FLOODING TO THESE AREAS. CURRENTLY...WE
HAVE NO INDICATIONS OF ANY SUCH RAIN EVENTS THROUGH NEXT WEEK SO A
BELOW NORMAL RISK FOR FLOODING SEEMS JUSTIFIED IN THESE AREAS.

THE POTENTIAL FOR FLOODING DUE TO ICE JAMS REMAINS ABOVE NORMAL AND
COULD POTENTIALLY BECOME SERIOUS LATER THIS WINTER OR SPRING FROM
THE MOHAWK RIVER NORTHWARD IN NEW YORK STATE AND ACROSS CENTRAL AND
ESPECIALLY NORTHERN NEW ENGLAND. IN THESE AREAS...SERIOUS ICE JAMS
CONTINUE TO CLOG MANY RIVERS AND ALTHOUGH FLOODING HAS
SUBSIDED...THE WARMER TEMPERATURES AND RAINFALL FORECAST OVER THE
NEXT WEEK TO 10 DAYS SUGGESTS ICE COULD BEGIN TO MOVE ACROSS
ESPECIALLY NEW YORK STATE AND VERMONT. IN THE NEAR TERM ( WITHIN THE
NEXT 10 DAYS )...WE ARE CONCERNED FOR SUBSTANTIAL MOVEMENT OF ICE
ALONG THE MOHAWK...BLACK...UPPER HUDSON AND AU SABLE RIVERS IN
NORTHERN NEW YORK STATE AND THE MISSISQUOI...WINOOSKI AND LAMOILLE
RIVERS IN NORTHERN VERMONT.

ALTHOUGH THERE IS SOME RISK FOR ICE MOVEMENT ACROSS NEW HAMPSHIRE
NEXT WEEK...MOST OF THE THREAT FROM NORTHERN NEW HAMPSHIRE INTO
MAINE IS ABOVE NORMAL IN THE LONGER TERM. IN THESE AREAS...ICE
THICKNESSES OF 1 TO 2 FEET WILL LIKELY BE THICK ENOUGH TO REMAIN IN
PLACE INTO EARLY MARCH SO IT IS THEN THAT THE THREAT IN THESE AREAS
WOULD BECOME MORE SERIOUS. WE DO THINK...HOWEVER...SOME ICE MOVEMENT
COULD OCCUR ON THE CONNECTICUT...PEMIGEWASSET AND PISCATAQUOG RIVERS
IN VERMONT AND NEW HAMPSHIRE NEXT WEEK DEPENDING UPON HOW MUCH
WARMTH AND RAINFALL ULTIMATELY DEVELOPS.

IT IS WORTHY NOTING THAT THE ICE JAM SITUATION CURRENTLY OCCURRING
IS THE WORST IT HAS BEEN IN THE PAST 20 YEARS FOR MID-WINTER ACROSS
MOST OF NORTHERN NEW ENGLAND AND NORTHERN NEW YORK STATE. UNTIL THE
ICE MOVES OUT...ANY LARGE SCALE THAW OR RUNOFF EVENT COULD POSE A
SERIOUS FLOOD POTENTIAL.

THE POTENTIAL FOR FLOODING DUE TO ICE JAMS HAS GREATLY IMPROVED
ACROSS SOUTHERN NEW ENGLAND AND SOUTHERN/WESTERN NEW YORK STATE AND
IS NOW NEAR TO BELOW NORMAL. THERE IS LITTLE IN THE WAY OF ICE LEFT
ACROSS SOUTHERN NEW ENGLAND AND SOUTHEAST NEW YORK STATE. AN ICE JAM
ON THE HOUSATONIC RIVER NEAR THE TOWN OF KENT IN CONNECTICUT HAS
WEAKENED SOME OVER THE PAST FEW WEEKS AND IS NOW CONSIDERED AT JUST
A NORMAL THREAT FOR FURTHER JAM RELATED FLOODING. LIKEWISE...SOME
ICE HAS REFORMED ALONG RIVERS AND CREEKS IN CENTRAL AND WESTERN NEW
YORK STATE BUT THAT ICE IS FAIRLY THIN AND WOULD LIKELY FLUSH OUT
DURING A SIGNIFICANT RUNOFF EVENT RATHER THAN CAUSE SIGNIFICANT
JAMMING. FOR THIS REASON...THE ICE JAM THREAT ACROSS CENTRAL AND
WESTERN NEW YORK STATE IS DEEMED NO HIGHER THAN NORMAL FOR MID-
FEBRUARY.

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 1 MARCH 2018.

END/HORWOOD
$$



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