Flood Potential Outlook
Issued by NWS Boston, MA

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CTC003-013-015-MAC001-005-007-009-011-013-015-017-019-021-023-025-
027-NHC005-011-RIC001-003-005-007-009-071930-

WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE TAUNTON MA
230 PM EST THU MAR 5 2015

...THE WINTER/SPRING FLOOD POTENTIAL IS ABOVE NORMAL ACROSS CENTRAL
AND EASTERN MASSACHUSETTS...RHODE ISLAND...AND MUCH OF NORTHERN
CONNECTICUT....

...THE WINTER/SPRING FLOOD POTENTIAL IS NEAR NORMAL ACROSS THE EAST
SLOPES OF THE BERKSHIRES AND THE CONNECTICUT RIVER IN
MASSACHUSETTS...

THE LATE WINTER/SPRING FLOOD POTENTIAL FOR RIVER AND STREAM FLOODING
IN SOUTHERN NEW ENGLAND IS ABOVE NORMAL...EXCEPT NEAR NORMAL ACROSS
THE EAST SLOPES OF THE BERKSHIRES AND THE CONNECTICUT RIVER IN
MASSACHUSETTS. THE POTENTIAL FOR FLOODING DUE TO ICE JAMS IS ABOVE
NORMAL. THE POTENTIAL FOR URBAN AND POOR DRAINAGE FLOODING IS ABOVE
NORMAL.

THIS IS THE FIFTH WINTER/SPRING FLOOD POTENTIAL OUTLOOK OF THE 2015
SEASON.  FLOOD OUTLOOKS WILL BE ISSUED EVERY TWO WEEKS INTO EARLY
SPRING TO ASSESS THE POTENTIAL FOR FLOODING.  THE OUTLOOKS ARE 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...ALONG WITH EXPECTED
TEMPERATURES AND PRECIPITATION OVER THE NEXT TWO WEEKS.

...RECENT PRECIPITATION AND TEMPERATURES...

FROM LATE JANUARY INTO EARLY MARCH...SOUTHERN NEW ENGLAND WAS
BOMBARDED WITH PERIODS OF SNOW COUPLED WITH WELL BELOW NORMAL
TEMPERATURES. RECORDS WERE BROKEN WITHIN THIS TIME FRAME. THE
FOLLOWING INFORMATION IS PRELIMINARY.

IN BOSTON...FEBRUARY 2015 WAS THE SECOND COLDEST MONTH ON RECORD
WITH TEMPERATURES AVERAGING 19.0 DEGREES F. FEBRUARY 2015 WAS THE
ALL TIME SNOWIEST MONTH ON RECORD FOR BOSTON WITH 64.8 INCHES. THE
SEASONAL SNOWFALL TOTAL THROUGH MARCH 4 WAS 105.7 INCHES...AT THIS
TIME 2014-2015 IS RANKED AS THE SECOND SNOWIEST SEASON ON RECORD.
THIS SEASONAL SNOWFALL TOTAL IS A STAGGERING 70.2 INCHES ABOVE
NORMAL TO DATE.

IN WORCESTER...FEBRUARY 2015 IS NOW THE NEW ALL TIME COLDEST MONTH
ON RECORD...WITH AN AVERAGE DAILY TEMPERATURE OF 14.2 DEGREES F.
FEBRUARY 2015 WAS THE ALL TIME SNOWIEST MONTH ON RECORD FOR
WORCESTER WITH 53.4 INCHES OF SNOW.  THE SEASONAL SNOWFALL TOTAL
THROUGH MARCH 4 WAS 115.6 INCHES...WHICH WAS ALMOST DOUBLE THE
NORMAL TO DATE...63.8 INCHES ABOVE NORMAL.

IN PROVIDENCE...FEBRUARY 2015 IS NOW THE SECOND COLDEST MONTH ON
RECORD...WITH AN AVERAGE DAILY TEMPERATURE OF 18.4 DEGREES. FEBRUARY
2015 WAS THE SECOND SNOWIEST MONTH ON RECORD...AT 31.8 INCHES. THE
SEASONAL SNOWFALL TOTAL THROUGH MARCH 4 WAS 67.2 INCHES...WHICH WAS
38.5 INCHES ABOVE NORMAL TO DATE.

IN HARTFORD...FEBRUARY 2015 IS NOW THE NEW ALL TIME COLDEST MONTH ON
RECORD...WITH AN AVERAGE DAILY TEMPERATURE OF 16.1 DEGREES F.
FEBRUARY WAS THE THIRD SNOWIEST FEBRUARY ON RECORD...WITH 31.9
INCHES OF SNOW.  THE SEASONAL SNOWFALL TOTAL THROUGH MARCH 4 WAS
59.3 INCHES...WHICH WAS 25.6 INCHES ABOVE NORMAL TO DATE.

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

DUE TO THE COMBINATION OF WELL BELOW NORMAL TEMPERATURES...A
MULTITUDE OF SNOWFALL EVENTS...AND A LACK OF A WINTER
THAW...SOUTHERN NEW ENGLAND DEVELOPED A ROBUST LATE SEASON SNOW PACK.

IN WESTERN MASSACHUSETTS...THE SNOW PACK IS NORMAL TO SOMEWHAT ABOVE
NORMAL FOR THIS TIME OF YEAR.  HOWEVER ACROSS THE REMAINDER OF
SOUTHERN NEW ENGLAND...THE SNOW PACK RANGED FROM ABOVE TO WELL ABOVE
NORMAL. THE SNOW PACK WAS THE MOST ANOMALOUS ACROSS EASTERN
MASSACHUSETTS INTO RHODE ISLAND.

ACROSS THE CONNECTICUT RIVER VALLEY AREA OF MASSACHUSETTS...EAST
SLOPES OF THE BERKSHIRES...AND NORTH CENTRAL CONNECTICUT...SNOW
DEPTHS RANGED FROM 1 TO 2 FEET WITH LOCALLY HIGHER DEPTHS.  SNOW
WATER EQUIVALENT IN THIS AREA RANGED FROM 3.5 TO 6 INCHES WITH
LOCALIZED HIGHER AMOUNTS ACROSS THE HIGHER TERRAIN OF NORTHWEST
MASSACHUSETTS.

ACROSS CENTRAL MASSACHUSETTS...MOST OF EASTERN
MASSACHUSETTS...NORTHEAST CONNECTICUT AND NORTHERN RHODE
ISLAND...SNOW DEPTHS RANGED FROM 18 TO 30 INCHES.  LOCALIZED HIGHER
TOTALS WERE NOTED...INCLUDING 31 INCHES IN BEVERLY...AND 35 INCHES
AT BLUE HILL.  SNOW WATER EQUIVALENTS RANGED FROM 5 TO 8 INCHES.
SOME OF THE HIGHEST MEASURED SNOW WATER EQUIVALENTS WERE IN EASTERN
MASSACHUSETTS.

ACROSS SOUTHERN RHODE ISLAND...SOUTH COASTAL MASSACHUSETTS AND THE
CAPE AND ISLANDS...SNOW DEPTHS RANGED FROM 6 INCHES TO 2 FEET.  SNOW
WATER EQUIVALENT RANGED FROM 2.5 TO 6 INCHES.

...RIVER AND ICE CONDITIONS...

RIVER FLOWS ACROSS MUCH OF SOUTHERN NEW ENGLAND ARE RUNNING BELOW TO
MUCH BELOW NORMAL.  THIS IS MAINLY DUE TO THE COLD WEATHER AND LACK
OF RUNOFF SINCE MID JANUARY...RATHER THAN DUE TO A LACK OF
PRECIPITATION.

THE ANOMALOUS COLD EXPERIENCED FROM LATE JANUARY THROUGH FEBRUARY
ENABLED THE DEVELOPMENT OF AN UNUSUAL AMOUNT OF ICE ON AREA
WATERWAYS.  WHILE MANY RIVERS AND STREAMS ARE NOT COMPLETELY ICED
OVER...AS A GENERAL RULE WE HAVE MUCH MORE ICE THAN IS TYPICAL FOR
EARLY MARCH.

ACROSS NORTHERN CONNECTICUT...STATE OFFICIALS REPORTED THAT WELL
EXPOSED RIVERS GENERALLY HAD ICE THICKNESS OF LESS THAN 6 INCHES
WITH 50 PERCENT ICE COVERAGE.  SOME SHADED STRETCHES OF RIVER HAD
ICE COVERAGE CLOSER TO 100 PERCENT...WITH THICKNESS UP TO A FOOT OR
MORE. THIS IS ABOVE NORMAL FOR THIS TIME OF YEAR.

IN SOUTHERN NEW ENGLAND...THE MOST SUBSTANTIAL ICE COVERAGE AND
THICKNESS IS LIKELY OVER NORTH CENTRAL AND WESTERN MASSACHUSETTS.
IN THIS AREA...RIVER ICE MAY BE UP TO A FOOT THICK IN SOME
AREAS...BUT COVERAGE AND THICKNESS ARE LIKELY TO VARY. THE NORTH
NASHUA RIVER IN FITCHBURG WAS REPORTED TO HAVE SUBSTANTIAL ICE
COVERAGE.  MEASUREMENTS IN THE ICE NEAR THE RIVER GAGE INDICATED
THICKNESS AT THAT SITE WAS 6 TO 12 INCHES.

GIVEN THE CURRENT EXTENT OF RIVER ICE ON AREA WATERWAYS...THE RIVER
ICE JAM FLOOD THREAT IS ABOVE NORMAL FOR THIS TIME OF YEAR ACROSS
SOUTHERN NEW ENGLAND. ANY RAIN OR RAINFALL/SNOW MELT EVENT THAT
PRODUCES A RISE OF 2 TO 3 FEET ON RIVERS AND STREAMS COULD CAUSE
BREAKUP AND MOVEMENT OF RIVER ICE...AND BRING THE POTENTIAL FOR
BREAK UP ICE JAMS.

HOWEVER...THE FORECAST FOR FRIDAY MARCH 6 THROUGH NEXT THURSDAY
MARCH 12 CALLS FOR MAINLY DRY CONDITIONS...WITH TEMPERATURES WARMING
TO NEAR NORMAL FOR NEXT WEEK. THE HIGHER SUN ANGLE AND INCREASED
SOLAR RADIATION WILL BRING OPPORTUNITY FOR SUBSTANTIAL RIVER ICE
DECAY. THE WEEK 2 OUTLOOK FROM THE CLIMATE PREDICTION CENTER CALLS
FOR NEAR NORMAL TEMPERATURES AND NORMAL TO BELOW NORMAL
PRECIPITATION...WHICH MAY AFFORD ANOTHER OPPORTUNITY FOR THE ICE TO
ROT. OVER THE NEXT 2 WEEKS THIS IS A SITUATION THAT WARRANTS
CONTINUED MONITORING.

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

AS OF MARCH 5 THE SOIL MOISTURE LEVELS ACROSS SOUTHERN NEW ENGLAND
WAS NORMAL TO ABOVE NORMAL FOR THIS TIME OF YEAR.  THE GROUND WAS
FROZEN TO AN UNKNOWN DEPTH.

EXAMINING GROUND WATER MONITORING WELLS ACROSS THE REGION COURTESY
OF THE UNITED STATES GEOLOGICAL SURVEY (USGS) MOST GROUND WATER
LEVELS WERE REPORTED TO BE NORMAL TO BELOW NORMAL LEVELS ACROSS
SOUTHERN NEW ENGLAND. SOME WELLS WERE AT ABOVE NORMAL LEVELS...THESE
WERE MAINLY IN WESTERN MASSACHUSETTS...CAPE COD...AND NANTUCKET.

WATER SUPPLY WAS NEAR NORMAL FOR THIS TIME OF YEAR.  QUABBIN
RESERVOIR WAS AT 95.4 PERCENT CAPACITY...WACHUSETT RESERVOIR AT 84.5
PERCENT CAPACITY...AND SCITUATE RESERVOIR IN RHODE ISLAND AT 86.4
PERCENT CAPACITY.

...TEMPERATURE AND PRECIPITATION OUTLOOK...

A BREAK IN THE COLD AND SNOWY CONDITIONS LOOKS TO BE IN SIGHT.
LOOKING AHEAD FROM FRIDAY MARCH 6 THROUGH NEXT THURSDAY...WHILE SOME
PRECIPITATION CAN NOT BE COMPLETELY RULED OUT...MAINLY DRY
CONDITIONS ARE EXPECTED FOR MUCH OF THE PERIOD. TEMPERATURES FOR
FRIDAY THROUGH THIS WEEKEND ARE EXPECTED TO BE BELOW NORMAL...BUT
THERE WILL BE A GRADUAL WARMING TREND. TEMPERATURES FOR MUCH OF THE
NEXT WORKWEEK ARE EXPECTED TO BE NEAR NORMAL.

BASED ON THIS FORECAST...A GRADUAL SNOWMELT IS EXPECTED TO BEGIN
THIS SUNDAY...WITH ADDITIONAL GRADUAL SNOWMELT DURING EACH DAY OF
THE NEXT WEEK. IN ADDITION...THE HIGHER SUN ANGLE WILL START TO ROT
SOME OF THE RIVER ICE THAT DEVELOPED IN FEBRUARY.

THE WEEK 2 OUTLOOK FROM THE CLIMATE PREDICTION CENTER FOR MARCH 12
TO 18...CALLS FOR NEAR NORMAL TEMPERATURES AND NORMAL
TO BELOW NORMAL PRECIPITATION.

...SUMMARY...

BASED ON THE INFORMATION AVAILABLE AT THIS TIME...THE LATE WINTER
AND SPRING FLOOD POTENTIAL IS ABOVE NORMAL ACROSS CENTRAL AND
EASTERN MASSACHUSETTS...RHODE ISLAND...AND MUCH OF NORTHERN
CONNECTICUT. THE LATE WINTER AND SPRING FLOOD POTENTIAL IS NEAR
NORMAL ACROSS WESTERN MASSACHUSETTS...INCLUDING THE CONNECTICUT
RIVER IN MASSACHUSETTS.

THE POTENTIAL FOR FLOODING DUE TO ICE JAMS IS ABOVE NORMAL. THE POOR
DRAINAGE FLOOD THREAT IS ABOVE NORMAL.

BECAUSE OF THE EXTENT OF SNOWPACK AND THE POTENTIAL FOR LINGERING
SNOW CLOGGED DRAINS...THE THREAT FOR URBAN AND POOR DRAINAGE
FLOODING IS ABOVE NORMAL. A LIGHT TO MODERATE RAIN WITH MODEST
SNOWMELT MAY BE SUFFICIENT TO CAUSE POOR DRAINAGE FLOODING IN SOME
LOCATIONS. THIS IS DEPENDENT ON THE EXTENT OF SNOW CLOGGED DRAINS
FROM ONE LOCATION TO THE NEXT.

OVER THE NEXT FEW WEEKS MULTIPLE ITEMS WILL NEED TO BE MONITORED
CLOSELY...INCLUDING THE EVOLUTION OF OUR LATE WINTER SNOWPACK...AND
THE RIVER ICE. WHILE THE SNOWPACK IN WESTERN MASSACHUSETTS IS NEAR
NORMAL...THE SNOWPACK IN NORTH CENTRAL CONNECTICUT AND CENTRAL
MASSACHUSETTS IS ABOVE NORMAL...AND THE SNOWPACK IN EASTERN
MASSACHUSETTS AND RHODE ISLAND RANGES FROM ABOVE NORMAL TO
ANOMALOUSLY ABOVE NORMAL. THE LATER WE GET INTO THE SEASON HOLDING
ON TO THE SNOW PACK...THE GREATER THE CHANCE THERE IS FOR WARM
WEATHER EVENTS WITH RAIN AND SNOWMELT...AND THE GREATER OVERALL LONG
TERM CHANCE THERE IS FOR FLOODING.

AT THIS TIME...THE POTENTIAL FOR FLOODING DUE TO ICE JAMS IS ABOVE
NORMAL ACROSS SOUTHERN NEW ENGLAND. OVER THE NEXT 2 WEEKS RIVER ICE
IS EXPECTED TO ROT AND DECAY. HOWEVER...UNTIL THE ICE IS
SUBSTANTIALLY THINNED...ITS THICKNESS AND COVERAGE LEAVE THE
OPPORTUNITY FOR ICE JAMS IF IT STARTS TO MOVE DUE TO ANY SUBSTANTIAL
RUNOFF. TWO WEEKS FROM NOW...HOWEVER...THE ICE JAM FLOOD THREAT
SHOULD SUBSIDE ACROSS MUCH OF THE AREA...WITH THE PROBABLE EXCEPTION
OF THE FAR INTERIOR.

IN THE FORECAST IT APPEARS WE ARE TURNING A CORNER...GOING FROM
BUILDING UP THE SNOW PACK...TO FINALLY STARTING TO MELT.  MAINLY DRY
CONDITIONS ARE IN THE FORECAST STARTING FRIDAY AND GOING INTO THE
NEXT WORKWEEK. WITH TEMPERATURES CLOSER TO NORMAL NEXT WEEK...AN
ONSET OF GRADUAL SNOWMELT IS EXPECTED. BASED ON THE WEEK 2 OUTLOOK
FROM THE CLIMATE PREDICTION CENTER...IT IS POSSIBLE THAT THIS TREND
MAY CONTINUE THROUGH MID MARCH.

KEEP IN MIND THAT HEAVY RAIN CAN CAUSE FLOODING ANY TIME OF THE
YEAR...EVEN WITHOUT A SNOWPACK. 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
WEATHER.GOV/BOSTON AND CLICK ON THE OPTION CURRENT HAZARDS...THEN
CLICK ON LOCAL OUTLOOK.

THE NEXT WINTER/SPRING FLOOD POTENTIAL OUTLOOK WILL BE ISSUED ON
THURSDAY MARCH 12.

$$

NMB

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