000 FGUS71 KBGM 212012 ESFBGM NYC007-015-017-023-025-053-065-067-077-097-099-101-105-107-109- 123-PAC015-069-079-103-115-127-131-042015- WINTER/SPRING FLOOD POTENTIAL OUTLOOK NATIONAL WEATHER SERVICE BINGHAMTON NY 412 PM EDT THU MAR 21 2013 ...SPRING FLOOD POTENTIAL OUTLOOK NUMBER 13-06... ...SUMMARY... THIS IS THE SIXTH IN A SERIES OF OUTLOOKS FOR THE SPRING SNOW MELT SEASON. THIS OUTLOOK IS DESIGNED TO PROVIDE A GENERALIZED ASSESSMENT OF THE FLOOD POTENTIAL ACROSS CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA FOR THE TWO WEEK PERIOD FROM MARCH 21ST TO APRIL 4TH 2013. THIS ASSESSMENT IS FOR THE NATIONAL WEATHER SERVICE (NWS) BINGHAMTON HYDROLOGIC SERVICE AREA, WHICH INCLUDES THE FINGER LAKES/ONEIDA LAKE/OSWEGO RIVER BASIN, CHEMUNG RIVER BASIN, NORTH BRANCH SUSQUEHANNA RIVER BASIN AND THE UPPER DELAWARE RIVER BASIN. THE OVERALL FLOOD POTENTIAL DURING THE NEXT TWO WEEKS IS BELOW NORMAL. ...DETAILS... CURRENT FLOODING - NONE. RECENT PRECIPITATION - DURING THE PAST TWO WEEKS, PRECIPITATION WAS ABOVE AVERAGE. PRECIPITATION DURING THE PAST 30 TO 90 DAYS HAS BEEN SLIGHTLY BELOW NORMAL. SNOW PACK CONDITIONS - SLIGHTLY ABOVE AVERAGE WITH SNOW DEPTHS RANGING FROM 2 TO 6 INCHES ACROSS MOST OF CENTRAL NEW YORK AND 1 TO 4 INCHES ACROSS NORTHEAST PENNSYLVANIA. THESE AMOUNTS WERE HIGHLY DEPENDENT ON ELEVATION...AND SOME OF THE LOWEST VALLEYS ACTUALLY HAVE LIMITED OR NO SNOW. SNOW WATER EQUIVALENT (SWE) VALUES - THE LIQUID EQUIVALENT OF THE SNOW PACK WAS UNDER ONE INCH ACROSS THE REGION. MELTING THIS EXISTING SNOW PACK WOULD BE HYDROLOGICALLY INSIGNIFICANT UNLESS ACCOMPANIED BY A SUBSTANTIAL RAINFALL EVENT. RIVER ICE CONDITIONS - ICE COVER WAS NON-EXISTENT ACROSS THE REGION. THIS IS NORMAL FOR LATE MARCH. STREAM AND RIVER CONDITIONS - FLOWS AVERAGED OVER THE PAST MONTH AT THE USGS INDEX MONITORING GAUGES WERE RUNNING NEAR TO BELOW NORMAL. SOIL MOISTURE CONDITIONS - THE LONG TERM PALMER DROUGHT INDEX AND THE U.S. CROP INDEX OBSERVED THROUGH MID MARCH WERE INDICATING NEAR NORMAL SOIL WETNESS ACROSS MUCH OF THE REGION...WITH A TENDENCY FOR ABOVE NORMAL WETNESS AROUND THE FINGER LAKES BASINS. GROUND WATER - WELL LEVELS ARE GENERALLY RUNNING NEAR TO BELOW NORMAL. RESERVOIR AND LAKE CONDITIONS - THE NEW YORK CITY WATER SUPPLY RESERVOIR STORAGE IN THE CATSKILLS OF NEW YORK / UPPER DELAWARE RIVER BASIN WAS 2.0 PERCENT ABOVE NORMAL AT A STORAGE CAPACITY OF 92.5 PERCENT. ARMY CORPS LAKE RESERVOIR PROJECTS ARE INDICATING SLIGHTLY ABOVE AVERAGE POOL HEIGHTS AS A RESULT OF RAIN AND SNOW MELT LAST WEEK, BUT WERE RAPIDLY TRENDING DOWN TOWARD NORMAL SPRING POOLS. THE FINGER LAKES ARE WITHIN THEIR MANAGED TARGET LEVELS FOR THIS TIME OF YEAR. FUTURE WEATHER CONDITIONS - OVERALL...THE NEXT TWO WEEKS ARE EXPECTED TO BE COLDER AND DRIER THAN NORMAL WITH MAINLY LIGHT TO MODERATE PRECIPITATION EVENTS EXPECTED. ADVANCED HYDROLOGIC PREDICTION SERVICES (AHPS) HISTORICAL PROBABILISTIC OUTLOOK - ACCORDING TO THIS GUIDANCE TOOL, THE PROBABILITY OF RIVER FLOODING IS EXPECTED TO BE BELOW AVERAGE WHEN COMPARED TO EXPECTED HISTORICAL FLOODING POTENTIAL THIS TIME OF YEAR. EXPERIMENTAL ENSEMBLE RIVER FORECAST MODEL PREDICTION - THE PROBABILITY OF RIVER FLOODING INDICATED BY THIS MODEL GROUP INDICATES ESSENTIALLY LITTLE TO NO CHANCE OF FLOODING OVER THE NEXT 10 DAYS. ANALYSIS SUMMARY... FLOOD POTENTIAL NEXT TWO WEEKS - BELOW NORMAL. RECENT PRECIPITATION - BELOW NORMAL. SNOW PACK CONDITIONS - SLIGHTLY ABOVE NORMAL. SNOW WATER EQUIVALENT (SWE) HYDROLOGICALLY INSIGNIFICANT. RIVER ICE CONDITIONS - NORMAL (NONE). STREAM AND RIVER CONDITIONS - AVERAGE TO BELOW AVERAGE FLOWS. SOIL MOISTURE CONDITIONS - NORMAL TO ABOVE NORMAL WETNESS. GROUND WATER - NORMAL TO BELOW NORMAL. RESERVOIR AND LAKE CONDITIONS - NORMAL TO ABOVE, TRENDING DOWN. FUTURE WEATHER CONDITIONS - COLDER AND DRIER THAN NORMAL. AHPS PROBABILITY FORECAST - CHANCES ARE BELOW THE HISTORICAL AVERAGE. ENSEMBLE RIVER FORECAST MODEL PREDICTION - LITTLE TO NO CHANCE FLOODING. ...CAVEATS... THE OUTLOOK ESTIMATES THE POTENTIAL FOR RIVER AND LAKE FLOODING BASED ON A CURRENT ASSESSMENT OF BROAD BASED HYDRO-METEOROLOGICAL FACTORS WHICH CONTRIBUTE TO RIVER AND LAKE FLOODING AS SHOWN ABOVE. HEAVY RAINFALL IS THE PRIMARY FACTOR WHICH LEADS TO RIVER AND LAKE FLOODING. INDIVIDUAL HEAVY RAIN STORMS CAN NOT BE PRECISELY PREDICTED WITHIN THIS OUTLOOK. HEAVY RAIN CAN DEVELOP ON SHORT NOTICE...AND RAPIDLY CAUSE FLOODING ANY TIME OF THE YEAR, EVEN WHEN THE OVERALL FLOOD POTENTIAL IS CONSIDERED BELOW AVERAGE. THIS OUTLOOK DOES NOT ATTEMPT TO ADDRESS FLASH FLOODING, OR THE SEVERITY OF ANY POSSIBLE FUTURE FLOODING. ...REFERENCES... MUCH MORE HYDROMETEOROLOGICAL INFORMATION CAN BE FOUND BY VISITING THESE NATIONAL WEATHER SERVICE INTERNET WEB SITES. HTTP://WEATHER.GOV/BGM (CLICK HYDROLOGY LINK) HTTP://WEATHER.GOV/NERFC HTTP://WEATHER.GOV/MARFC HTTP://WWW.NOHRSC.NOAA.GOV (FOR SNOW INFORMATION) THE NEXT WINTER/SPRING FLOOD OUTLOOK WILL BE ISSUED BY THIS OFFICE IN TWO WEEKS, ON APRIL 4, 2013. $$ JAB