000
FGUS71 KBUF 080117
ESFBUF
NYC003-009-011-013-029-037-045-049-051-055-063-069-073-075-117-
121-220130-

WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE BUFFALO NY
817 PM EST THU MAR 7 2013

...BELOW NORMAL FLOOD POTENTIAL THROUGH LATE MARCH...
...A RISK FOR GENERALLY MINOR FLOODING IN THE BUFFALO AND
   ROCHESTER CREEKS EARLY NEXT WEEK...

THIS IS THE FIFTH WINTER / SPRING FLOOD POTENTIAL OUTLOOK OF THE
2012 SEASON. FLOOD OUTLOOKS WILL BE ISSUED EVERY TWO WEEKS INTO
EARLY SPRING TO SUMMARIZE BASIN HYDROMETEOROLOGICAL CONDITIONS AND
TO ASSESS THE POTENTIAL FOR FLOODING. THE OUTLOOKS ARE BASED ON
CURRENT AND FORECAST HYDROMETEOROLOGICAL CONDITIONS. THIS INCLUDES
SNOW COVER AND SNOW WATER EQUIVALENT...CREEK AND RIVER LEVELS AND
THE AMOUNT OF ICE COVER ON THEM...ALONG WITH THE EXPECTED
PRECIPITATION OVER THE NEXT TWO WEEKS.

...CURRENT CONDITIONS SUMMARY...

THERE HAS BEEN ONLY LIMITED CHANGE IN THE SNOW PACK OVER THE PAST
COUPLE WEEKS. THE MOST SIGNIFICANT EVENT CAME LATE FEBRUARY...WHEN
A COLD RAIN FELL ACROSS MOST OF THE REGION. THIS HAD A MIXED
IMPACT ON SNOW PACK. THE RAIN RESULTED IN MAINLY RUN OFF IN AREAS
WITH A SHALLOW SNOW PACK. HOWEVER...IN AREAS OF DEEPER SNOW
PACK...THE RAIN WAS ABSORBED BY THE SNOW AND ADDED TO THE WATER
EQUIVALENT OF THE SNOW PACK.

OTHERWISE...THERE WAS NO SIGNIFICANT PRECIPITATION DURING THE 
PERIOD. LIGHT SNOWS IN EARLY MARCH BROUGHT ONLY A MODEST INCREASE IN 
SNOW PACK. MEANWHILE...TEMPERATURES AVERAGED NEAR NORMAL LATE 
FEBRUARY...THEN BELOW NORMAL EARLY MARCH. THIS RESULTED IN LITTLE 
SNOW MELT DURING THE PERIOD. HOWEVER...OVERNIGHT LOWS WERE 
GENERALLY NOT COLD ENOUGH TO SIGNIFICANTLY EXPAND RIVER AND CREEK 
ICE.

THE RESULT IS THAT WATER EQUIVALENTS CONTINUE TO RUN BELOW NORMAL ACROSS
THE MAJORITY OF THE REGION. THE MOST SIGNIFICANT SNOW PACK IS IN
THE BLACK RIVER BASIN...WHERE ACTIVE LAKE SNOWS IN FEBRUARY BUILT
UP A SIGNIFICANT SNOW PACK. WATER EQUIVALENTS IN THE BLACK RIVER
BASIN ARE THE CLOSEST TO NORMAL...AVERAGING ABOUT 10 PERCENT
BELOW NORMAL VALUES FOR THIS TIME OF YEAR.

RIVER AND CREEK ICE IS BELOW NORMAL ACROSS THE REGION SINCE THERE
NOT BEEN ANY SIGNIFICANTLY COLD OVERNIGHT LOWS. RIVERS WERE
LARGELY CLEARED OUT IN JANUARY DUE TO A COUPLE SIGNIFICANT THAWS.
THERE IS STILL THIN OR PATCHY ICE ON MANY OF THE CREEKS...WITH THE
THICKEST ICE IN THE BLACK RIVER BASIN WHERE TEMPERATURES TEND TO
BE THE COLDEST.

THE FOLLOWING IS A SUMMARY OF CONDITIONS AND OUTLOOK BY BASIN AS
OF THURSDAY MORNING ON MARCH 7TH:

...BUFFALO AREA CREEKS / LAKE ERIE BASIN...
.SNOW COVER..........UP TO 3 INCHES LAKESHORE...5 TO 10 INCHES HEADWATERS.
.WATER EQUIVALENT....UP TO A HALF INCH LAKESHORE...1 TO 2 INCHES HEADWATERS.
.CREEK FLOWS.........NEAR NORMAL.
.CREEK ICE...........THIN.
.GROUND FROST........6 TO 12 INCHES.
.GROUND STATE........FROZEN.

...GENESEE RIVER BASIN / FINGER LAKES / ROCHESTER AREA...
.SNOW COVER..........UP TO 3 INCHES...4 TO 8 INCHES UPPER GENESEE.
.WATER EQUIVALENT....UP TO A HALF INCH...1 TO 2 INCHES UPPER GENESEE.
.RIVER/CREEK FLOWS...NEAR NORMAL.
.RIVER/CREEK ICE.....THIN.
.GROUND FROST........AROUND 6 INCHES.
.GROUND STATE........FROZEN.

...ALLEGHENY RIVER BASIN...
.SNOW COVER..........5 TO 10 INCHES.
.WATER EQUIVALENT....1 TO 2 INCHES.
.RIVER/CREEK FLOWS...BELOW NORMAL.
.RIVER CREEK ICE.....SOME.
.GROUND FROST........AROUND 12 INCHES.
.GROUND STATE........FROZEN.

...BLACK RIVER BASINS / TUG HILL...
.SNOW COVER..........8 TO 16 INCHES...16 TO 30 INCHES ON TUG HILL.
.WATER EQUIVALENT....AROUND 2 INCHES...4 TO 8 INCHES ON TUG HILL.
.RIVER/CREEK FLOWS...NEAR NORMAL.
.RIVER/CREEK ICE.....MODERATE.
.GROUND FROST........12 TO 18 INCHES.
.GROUND STATE........FROZEN.

...TEMPERATURE AND PRECIPITATION OUTLOOK...
THERE WILL BE A SIGNIFICANT WARM UP THIS UPCOMING WEEKEND...WITH
TEMPERATURES LIKELY TO RISE INTO THE 50S ACROSS MUCH OF WESTERN
NEW YORK...JUST A TAD COOLER IN THE BLACK RIVER BASIN. THIS IS
LIKELY TO RESULT IN SIGNIFICANT SNOW MELT IN THE BUFFALO CREEKS
AND GENESEE AND ALLEGHENY BASINS. GIVEN THE BELOW NORMAL SNOW
COVER...IT IS LIKELY THAT ALL BUT THE DEEPEST OF SNOWS WILL
PROBABLY BE MELTED IN THESE BASINS DURING THE WARM UP. IN THE
BLACK RIVER BASIN...THIS WARM UP WILL PROBABLY RIPEN THE
SNOWPACK...BUT SHOULD NOT RESULT IN TOO MUCH RUN OFF GIVEN THE
DEEP SNOW PACK AND SLIGHTLY COOLER TEMPERATURES.

EARLY NEXT WEEK A FRONT IS FORECAST TO CROSS IN THE MONDAY AND
TUESDAY TIMEFRAME. THIS BOUNDARY IS EXPECTED TO BE SLOW
MOVING...BUT NOT TO STALL. RAINFALL ASSOCIATED WITH THIS FRONT
WILL VARY...BUT GENERALLY A HALF INCH TO AN INCH OF RAIN APPEARS LIKELY.

BEHIND THIS FRONT...THE REGION WILL LIKELY BE IN A COOL AND FAIRLY
DRY REGIME FROM THE MIDDLE PART OF NEXT WEEK THROUGH MARCH 21ST. A
PERSISTENT UPPER TROF IS EXPECTED TO DEVELOP TO OUR EAST...WHICH
WILL LIKELY KEEP TEMPERATURES BELOW NORMAL. WHILE PERIODS OF
PRECIPITATION ARE EXPECTED...THE CONTINENTAL FLOW GENERALLY LACKS
A SIGNIFICANT MOISTURE SOURCE. THIS FORECAST PATTERN FOR MID TO
LATE MARCH IS NOT FAVORABLE FOR HEAVY RAINFALL IN OUR REGION.

...FLOOD POTENTIAL OUTLOOK...

FOR THE MOST PART...THERE IS BELOW NORMAL FLOOD POTENTIAL FOR THE
REGION THROUGH LATE MARCH. SNOWPACK AND RIVER ICE ARE GENERALLY
BELOW NORMAL...AND THE OVERALL WEATHER PATTERN IS NOT FAVORABLE
FOR A SIGNIFICANT HEAVY RAIN EVENT.

HOWEVER...A WARM UP FORECAST FOR THIS WEEKEND WILL LIKELY MELT
MOST OF THE THIN SNOW PACK SOUTH OF LAKE ONTARIO. IN ADDITION TO
THIS SNOW MELT...A LIGHT TO MODERATE RAINFALL IS EXPECTED ON
MONDAY AND TUESDAY OF NEXT WEEK. THIS COMBINATION WILL CAUSE
CREEKS AND RIVERS TO RISE...AND COULD RESULT IN FLOODING. FORECAST ENSEMBLES
SUGGEST THE POTENTIAL FOR FLOODING IS MAINLY CONFINED TO SMALLER
BASINS SUCH AS THE BUFFALO AND ROCHESTER CREEKS. IN EACH
CASE...PROBABILITIES FOR FLOODING ARE STILL LOW...AND ANY FLOODING
WOULD PROBABLY BE OF THE MINOR VARIETY. LARGER RIVERS ARE LESS
SUSCEPTIBLE TO FLOODING GIVEN THE LIMITED RAINFALL EXPECTED. THERE
IS ALSO A FAIRLY LOW RISK FOR FLOODING IN THE BLACK RIVER BASIN
WHERE SNOW PACK WILL PROBABLY NOT BE RIPE ENOUGH FOR SIGNIFICANT
RUN OFF. IT IS ALSO WORTH NOTING THAT LIMITED ICE ON THE CREEKS
WILL HELP MITIGATE ICE JAM POTENTIAL...HOWEVER SOME ICE IN THE
HEADWATERS MAY RESULT IN A FEW ICE JAMS.

BEYOND THIS...MOST OF THE SNOW WILL LIKELY BE GONE SOUTH OF LAKE
ONTARIO BY LATE NEXT WEEK. MEANWHILE...A COOLER THAN NORMAL
PATTERN...WITH FREQUENT BUT GENERALLY LIGHT PRECIPITATION WILL
RESULT IN AN OVERALL LOW FLOOD POTENTIAL FOR THE LATTER PART OF
NEXT WEEK ALL THE WAY THROUGH MARCH 21ST. SNOW PACK WILL LIKELY
REMAIN IN PLACE IN THE BLACK RIVER BASIN...BUT WITHOUT A
SIGNIFICANT RAINFALL EXPECTED DURING THIS PERIOD...THE POTENTIAL
FOR FLOODING IS BELOW NORMAL THERE AS WELL.

...ADDITIONAL INFORMATION...

REAL TIME RIVER INFORMATION AND PROBABILISTIC FORECASTS FOR
SPECIFIC LOCATIONS ALONG RIVERS ACROSS WESTERN NEW YORK CAN BE
FOUND ON THE INTERNET AT WWW.WEATHER.GOV/BUF BY CLICKING ON THE
RIVERS AND LAKES AHPS LINK ON THE LEFT SIDE OF THE PAGE. SINCE
CONDITIONS CAN CHANGE PLEASE REFER TO THE LATEST FLOOD
WARNINGS...WATCHES...AND STATEMENTS FOR ADDITIONAL INFORMATION.

THE NEXT REGULARLY SCHEDULED OUTLOOK WILL BE ISSUED BY THURSDAY
MARCH 21ST. THANKS TO ALL THE OBSERVERS AND AGENCIES WHICH HAVE
HELPED GATHER DATA IN SUPPORT OF THIS OUTLOOK.

$$

APFFEL