National Weather Service Text Product Display

Flood Potential Outlook
Issued by NWS Portland, ME
Versions: 1 2 3
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FGUS71 KGYX 182320
ESFGYX
MEC001-005-007-011-013-015-017-023-025-027-031-NHC001-003-007-009-
013-015-017-019-201915-

WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE GRAY ME
700 PM EDT THU APR 19 2013

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

THE FLOOD POTENTIAL IS SLIGHTLY ABOVE NORMAL IN THE MOUNTAINS OF
MAINE AND NORTHERN NEW HAMPSHIRE AND NEAR NORMAL ELSEWHERE.
THE POTENTIAL FOR FLOODING DUE TO ICE JAMS IN WESTERN MAINE AND NEW
HAMPSHIRE HAS PASSED FOR THE SEASON.

THIS IS THE SEVENTH IN A SERIES OF REGULARLY SCHEDULED HYDROLOGIC
OUTLOOKS ISSUED DURING THE WINTER AND SPRING SEASON. 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...

OVER THE PAST 2 WEEKS THE BLOCKING PATTERN THAT HAD BEEN AFFECTING
THE NORTHEAST HAS SLOWLY BROKEN DOWN. THIS HAS ALLOWED MILDER
TEMPERATURES TO MOVE INTO NORTHERN NEW ENGLAND. THE SNOWPACK HAS
BEEN SLOWLY MELTING AND PRECIPITATION HAS BEEN BELOW NORMAL. IN
THE SHORT TERM MILDER WEATHER IS ANTICIPATED ACROSS THE REGION BUT
THE PATTERN IS EXPECTED TO BE ACTIVE OVER THE NEXT 2 WEEKS. RIVER
LEVELS ARE EXPECTED TO SLOWLY RISE AS THE REMAINING SNOWPACK MELTS
AWAY AND MORE FREQUENT RAIN EVENTS MOVE THROUGH THE REGION.
THE OFFICIAL NATIONAL WEATHER SERVICE 6 TO 10 DAY FORECAST CALLS FOR
ABOVE NORMAL TEMPERATURES AND ABOVE NORMAL PRECIPITATION. THE 8 TO
14 DAY FORECAST CALLS FOR NORMAL TEMPERATURES AND NORMAL
PRECIPITATION.

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

...NEW HAMPSHIRE...

SNOW IS NOW CONFINED TO THE HIGHER ELEVATIONS OF NORTHERN NEW
HAMPSHIRE. SNOW DEPTH OF UP TO 18 INCHES WITH LOCALLY HIGHER AMOUNTS
ARE ON THE GROUND ABOVE 1500 FEET IN THE UPPER PEMIGEWASSET AND SACO
RIVER BASINS AND FROM MOUNT WASHINGTON NORTH TO THE CANADIAN BORDER.
SNOW WATER EQUIVALENT IN THESE AREAS RANGES FROM 2 TO 8 INCHES. A
SNOW SURVEY REPORT FROM TRANSCANADA NEAR MOOSE FALLS IN FAR NORTHERN
NEW HAMPSHIRE ON APRIL 16 SHOWED 30 INCHES OF SNOW WITH 9.4 INCHES
OF WATER EQUIVALENT AT AN ELEVATION OF 1950 FEET. A REPORT FROM THE
CORPS OF ENGINEERS AT BREEZY POINT SHOWED A SNOW DEPTH OF 17 INCHES
AND A WATER EQUIVALENT OF 7.6 INCHES AT AN ELEVATION OF 2500 FEET.

...MAINE...

SNOW IS NOW CONFINED TO THE MOUNTAINS OF MAINE WITH SNOW DEPTHS
RANGING FROM 2 TO 15 INCHES WITH LOCALLY HIGHER AMOUNTS. SNOW WATER
EQUIVALENT RANGES FROM 2 TO 8 INCHES WITH LOCALLY HIGHER AMOUNTS.
SNOW SURVEYS DONE BY BROOKFIELD POWER ON APRIL 15 SHOWED 31 INCHES
OF SNOW WITH 14.6 INCHES OF WATER EQUIVALENT AT PARLIN POND AT AN
ELEVATION OF 1700 FEET. AT SMILEY HILL 21 INCHES OF SNOW WAS
REPORTED WITH 11.4 INCHES OF WATER EQUIVALENT AT AN ELEVATION OF
1600 FEET. SOUTH OF THE MOUNTAINS THE GROUND IS NOW BARE.

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

SOIL MOISTURE INDICATORS ARE SHOWING NEAR TO ABOVE NORMAL IN AREAS
WHERE ACTIVE SNOW IS STILL OCCURRING. THE LONG TERM PALMER DROUGHT
SEVERITY INDEX SHOWS NORMAL MOISTURE CONDITIONS ACROSS MAINE AND NEW
HAMPSHIRE. AS REPORTED BY THE USGS GROUNDWATER LEVELS ARE MOSTLY
NEAR NORMAL IN WESTERN MAINE AND NEW HAMPSHIRE.

RESERVOIR LEVELS IN THE KENNEBEC RIVER BASIN WERE 43.4 PERCENT FULL
WHICH IS 7.4 PERCENT BELOW NORMAL. RESERVOIRS IN THE ANDROSCOGGIN
BASIN ARE 45.9 PERCENT FULL WHICH IS 0.9 PERCENT ABOVE NORMAL.

WATER SUPPLY SHORTAGES ARE NOT ANTICIPATED THIS SPRING.

...RIVER AND ICE CONDITIONS...

RIVER FLOWS ARE GENERALLY NEAR TO SOMEWHAT ABOVE NORMAL IN NORTHERN
NEW HAMPSHIRE BUT BELOW NORMAL IN SOUTHERN AREAS. IN MAINE RIVER
FLOWS ARE NEAR NORMAL IN SOUTHERN AREAS AND ABOVE NORMAL IN AREAS
CLOSER TO ACTIVE SNOWMELT.

THE THREAT OF ICE JAM FLOODING HAS PASSED FOR THE SEASON.

...IN CONCLUSION...

BASED ON THE ABOVE INFORMATION...THE WINTER/SPRING FLOOD POTENTIAL
THE FLOOD POTENTIAL IS SLIGHTLY ABOVE NORMAL IN THE MOUNTAINS OF
MAINE AND NORTHERN NEW HAMPSHIRE AND NEAR NORMAL ELSEWHERE. THE
POTENTIAL FOR FLOODING DUE TO ICE JAMS IN WESTERN MAINE AND NEW
HAMPSHIRE HAS PASSED FOR THE SEASON.

WITH ABOVE NORMAL TEMPERATURES EXPECTED AND A MORE ACTIVE WEATHER
PATTERN RIVERS WILL BE RISING SLOWLY AS THE REMAINING SNOWPACK MELTS
AWAY.

IT IS IMPORTANT TO NOTE HOWEVER THAT MAJOR FLOODING DOES NOT OCCUR
FROM SNOW MELT 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 MAY 3.

$$

TFH
National Weather Service Weather Forecast Office
