BOF 000 FGUS71 KGYX 181601 ESFGYX MEZ007>009-012>014-018>028-NHZ001>010-013-014-191600- HYDROLOGIC OUTLOOK NATIONAL WEATHER SERVICE GRAY ME 1200 PM EST FRI APR 18 2008 ...WINTER/SPRING FLOOD POTENTIAL OUTLOOK... THE FLOOD POTENTIAL IS ABOVE NORMAL FOR WESTERN MAINE AND NORTHERN...CENTRAL AND SOUTHEAST NEW HAMPSHIRE. THE THREAT OF ICE JAM FLOODING HAS PASSED. ...CLIMATOLOGICAL GUIDANCE... SINCE EARLY DECEMBER THE NORTHEAST HAD BEEN IN A VERY ACTIVE WEATHER PATTERN WITH AN ABUNDANCE OF PRECIPITATION AND SNOW. APRIL HAS SEEN A CHANGE IN THE PATTERN WITH MUCH DRIER CONDITIONS AND WARMING TEMPERATURES. THE OVERALL WARM WEATHER PATTERN IS EXPECTED TO PERSIST OVER THE NEXT 6-10 DAYS AS MOST OF THE NORTHEASTERN UNITED STATES REMAINS UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE. THE ONE EXCEPTION COULD BE A CUTOFF LOW PRESSURE SYSTEM FORECAST TO DEVELOP ACROSS THE MIDDLE MISSISSIPPI RIVER VALLEY THIS WEEKEND. THIS LOW MAY END UP MOVING NORTHEAST OVER THE WEEKEND...POSSIBLY BRINGING SOME RAIN AND COOLER TEMPERATURES TO NEW ENGLAND EARLY NEXT WEEK. AS WE HEAD INTO THE LATTER PART OF APRIL...THE OFFICIAL NATIONAL WEATHER SERVICE OUTLOOK CALLS FOR PRECIPITATION TO INCREASE AND AVERAGE ABOVE NORMAL ACROSS ALL OF NEW ENGLAND FROM APRIL 23RD THROUGH MAY 1ST. ...OBSERVED SNOW DEPTH AND WATER EQUIVALENT... ...NEW HAMPSHIRE... ...SNOW DEPTH... ACROSS THE SOUTHERN THIRD OF NEW HAMPSHIRE MOST OF THE SNOWPACK HAS MELTED AWAY EXCEPT FOR THE WOODED AREAS IN THE HIGHER TERRAIN OF WESTERN MERRIMACK COUNTY AND EASTERN SULLIVAN COUNTY. IN THOSE AREAS SNOW DEPTHS WERE GENERALLY LESS THAN 8 INCHES. IN CENTRAL NEW HAMPSHIRE GENERALLY FROM LAKE WINNIPESAUKEE NORTH TO THE WHITE MOUNTAINS AND EAST OF THE CONNECTICUT RIVER VALLEY SNOW DEPTHS RANGED FROM 6 TO 20 INCHES. AT ELEVATIONS ABOVE 1500 FEET SNOW DEPTHS WERE IN THE 24 TO 36 INCH RANGE. A SNOW SURVEY REPORT FROM THE CORP OF ENGINEERS REPORTED A SNOW DEPTH OF 36 INCHES AT AN ELEVATION OF 2500 FEET NEAR WARREN NEW HAMPSHIRE. IN NORTHERN NEW HAMPSHIRE SNOW DEPTHS RANGED FROM 6 TO 10 INCHES IN THE VALLEYS TO OVER 40 INCHES IN THE HIGHER TERRAIN OVER PORTIONS OF FAR NORTHERN AND EASTERN COOS COUNTY. A SNOW SURVEY REPORT FROM MOOSE FALLS EARLIER THIS WEEK INDICATED A SNOW DEPTH OF 39 INCHES. SNOW DEPTH WAS ABOVE NORMAL IN CENTRAL AND NORTHERN NEW HAMPSHIRE FOR THE TIME OF YEAR AND NEAR NORMAL IN THE SOUTH. ...SNOW WATER EQUIVALENT... IN THE HIGHER TERRAIN OF WESTERN MERRIMACK COUNTY AND EASTERN SULLIVAN COUNTY SNOW WATER EQUIVALENTS RANGED FROM 2 TO 4 INCHES. IN CENTRAL NEW HAMPSHIRE FROM LAKE WINNIPESAUKEE NORTH TO THE WHITE MOUNTAINS AND EAST OF THE CONNECTICUT RIVER VALLEY SNOW WATER EQUIVALENTS RANGED FROM 3 TO 7 INCHES AT ELEVATIONS BELOW 1500 FEET...WHILE ELEVATIONS ABOVE 1500 FEET RANGED FROM 6 TO 12 INCHES. IN NORTHERN NEW HAMPSHIRE SNOW WATER EQUIVALENTS RANGED FROM 3 TO 6 INCHES IN THE VALLEYS AND INCREASED TO 6 TO 12 INCHES IN THE HIGHER TERRAIN. MOOSE FALLS REPORTED 12.8 INCHES OF WATER IN THE SNOWPACK EARLIER THIS WEEK. SNOW WATER EQUIVALENTS WERE ABOVE NORMAL IN CENTRAL AND NORTHERN NEW HAMPSHIRE FOR THE TIME OF YEAR AND NEAR NORMAL IN THE SOUTH. ...MAINE... ...SNOW DEPTH... THE SNOWPACK HAS PRETTY MUCH MELTED AWAY IN COASTAL AREAS SOUTH AND EAST OF A LINE FROM BANGOR TO PITTSFIELD TO BELGRADE TO AUBURN TO SPRINGVALE. NORTH AND WEST OF THIS LINE TO THE FOOTHILLS SNOW DEPTHS RANGED FROM 3 TO 18 INCHES. IN THE WESTERN MAINE MOUNTAINS THERE REMAINED A TREMENDOUS AMOUNT OF SNOW ON THE GROUND FOR THE TIME OF YEAR. THERE...SNOW DEPTHS RANGED FROM 18 TO 36 INCHES WITH LOCALLY HIGHER AMOUNTS. SNOW DEPTHS WERE ABOVE NORMAL ACROSS THE WESTERN MOUNTAINS AND FOOTHILLS. SNOW DEPTHS WERE NEAR NORMAL ALONG THE COAST. ...SNOW WATER EQUIVALENT... OVER THE FOOTHILLS AND WESTERN INTERIOR SECTIONS SNOW WATER EQUIVALENTS RANGED FROM 1 TO 6 INCHES. IN THE WESTERN MAINE MOUNTAINS SNOW WATER EQUIVALENTS RANGED FROM 6 TO AS MUCH AS 12 INCHES. A SNOW SURVEY DONE EARLIER THIS WEEK IN GRAFTON NOTCH STATE PARK INDICATED 12.8 INCHES OF WATER IN THE SNOWPACK. ...SOIL MOISTURE AND WATER SUPPLY CONDITIONS... RESERVOIR LEVELS WERE WELL ABOVE NORMAL AT FIRST CONNECTICUT LAKE AND LAKE FRANCIS IN THE UPPER CONNECTICUT RIVER BASIN. RESERVOIR LEVELS HAVE DROPPED BELOW NORMAL FOR THE TIME OF YEAR FROM CENTRAL NEW HAMPSHIRE INTO WESTERN MAINE. THIS IS DUE TO THE FACT THAT RIVER BASIN MANAGERS HAVE BEEN ACTIVELY LOWERING LEVELS TO PREPARE FOR THE SPRING FRESHET. OVER THE LAST WEEK OR SO RESERVOIR LEVELS WERE STARTING TO RISE...BUT REMAINED BELOW NORMAL. RESERVOIRS IN THE KENNEBEC RIVER BASIN WERE 31 PERCENT FULL WHICH IS 39 PERCENT BELOW NORMAL. RESERVOIRS SHOULD HAVE NO PROBLEM FILLING THIS SPRING WITH THE TREMENDOUS AMOUNT OF SNOW ON THE GROUND IN THE UPPER REACHES OF THE RIVER BASINS. SOIL MOISTURE REMAINED WELL ABOVE NORMAL FOR THE TIME OF YEAR. THE PALMER DROUGHT SEVERITY INDEX WAS IN THE VERY MOIST TO EXTREMELY MOIST CATEGORY. GROUNDWATER LEVELS WERE NEAR TO SOMEWHAT BELOW NORMAL IN THE NORTH AND NEAR TO SOMEWHAT ABOVE NORMAL IN THE SOUTH. GROUNDWATER LEVELS ARE NOW RISING AS THE SPRING RUNOFF HAS STARTED. WATER SUPPLY SHORTAGES ARE NOT ANTICIPATED THIS SPRING. ...RIVER AND ICE CONDITIONS... RIVER LEVELS ARE ABOVE NORMAL FOR THE TIME OF YEAR. THE THREAT FOR ICE JAM FLOODING HAS PASSED AS ICE HAS MOVED OUT OF MOST RIVERS AND STREAMS. IN FAR NORTHERN NEW HAMPSHIRE AND THE WESTERN MAINE MOUNTAINS WHERE SOME ICE REMAINS...IT WAS ROTTING QUICKLY IN PLACE AS THE MID APRIL SUN WORKS AT MELTING IT OUT. ...IN CONCLUSION... WHILE WEATHER CONDITIONS OVER THE PAST 2 WEEKS HAVE BEEN FAIRLY IDEAL FOR SLOWLY MELTING THE SNOWPACK...THERE REMAINS A SIGNIFICANT AMOUNT OF SNOW ON THE GROUND IN THE HEADWATERS OF ALL THE MAJOR RIVERS FROM THE KENNEBEC RIVER WEST TO THE UPPER CONNECTICUT RIVER. A HEAVY RAIN EVENT COMBINED WITH RUNOFF FROM SNOWMELT COULD RESULT IN SIGNIFICANT FLOODING. FOR THIS REASON THE FLOOD POTENTIAL REMAINS ABOVE NORMAL. A DEEP AND MOISTURE FILLED SNOWPACK AS WELL AS HIGHER THAN NORMAL RIVER FLOWS AND HIGH SOIL MOISTURE SUPPORT THE ABOVE NORMAL FLOOD POTENTIAL. WEATHER CONDITIONS WILL HAVE TO BE MONITORED CLOSELY IN THE WEEKS AHEAD AS A HEAVY RAIN ON A RIPE AND WATER FILLED SNOWPACK COULD CAUSE SERIOUS FLOODING. IN ADDITION...MINOR FLOODING COULD RESULT FROM THE ONGOING SNOWMELT EVEN IF THE RECENT PATTERN OF WARM DAYS...COLD NIGHTS AND DRY WEATHER PERSISTS. THE THREAT FOR ICE JAM FLOODING IS OVER FOR THIS SEASON. 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 SPRING FLOOD POTENTIAL OUTLOOK WILL BE ISSUED ON MAY 2. $$ WHEELER EOF