Flood Potential Outlook
Issued by NWS Blacksburg, VA

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WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE BLACKSBURG VA
300 PM EDT THU MAR 17 2016

...WINTER/SPRING FLOOD OUTLOOK...NUMBER 6...FINAL

...RIVER FLOOD POTENTIAL SLIGHTLY BELOW NORMAL...

THIS IS THE SIXTH AND FINAL IN A SERIES OF ANNUAL WINTER/SPRING
FLOOD POTENTIAL STATEMENTS INTENDED TO PROVIDE INSIGHT INTO THE
LIKELIHOOD OF RIVER FLOODING (NOT FLASH FLOODING) ACROSS THE
BLACKSBURG HYDROLOGIC SERVICE AREA (HSA). THE HSA INCLUDES ALL OR
PARTS OF THE JAMES...ROANOKE...UPPER
YADKIN...GREENBRIER...NEW...CLINCH AND HOLSTON RIVER BASINS IN
WESTERN VIRGINIA...SOUTHEAST WEST VIRGINIA AND NORTHWEST NORTH
CAROLINA.

THESE STATEMENTS PROVIDE INFORMATION ON FLOOD THREAT CONDITIONS
SUCH AS RECENT PRECIPITATION...SOIL MOISTURE...SNOW COVER AND ITS
WATER EQUIVALENT...RIVER ICE CONDITIONS...STREAMFLOW...FUTURE
PRECIPITATION AND OTHERS FACTORS.

IN THIS PART OF THE MID-ATLANTIC REGION...IT IS HEAVY RAINFALL THAT
IS THE PRIMARY FACTOR LEADING TO RIVER FLOODING. HEAVY RAINFALL CAN
RAPIDLY CAUSE RIVER FLOODING AT ANY TIME OF THE YEAR...EVEN WHEN
OVERALL RIVER FLOOD POTENTIAL IS CONSIDERED LOW.

THIS OUTLOOK IS VALID FOR THE TWO-WEEK PERIOD THROUGH MARCH 31 2016.

THE FLOOD POTENTIAL FOR THE NEXT TWO WEEKS IS SLIGHTLY BELOW
NORMAL...BASED ON THE CURRENT HYDROLOGIC CONDITIONS AND BELOW
NORMAL PRECIPITATION FORECASTS.

CURRENT FLOODING...

THERE IS NO FLOODING AT THIS TIME.

RECENT PRECIPITATION...

MARCH TO DATE HAS SEEN PRECIPITATION NEAR NORMAL IN MOST OF THE HSA
WITH GENERALLY 1 TO 2.5 INCHES SO FAR THIS MONTH. THE EXCEPTION
IS IN PARTS OF THE NORTH CAROLINA PIEDMONT WHICH HAVE SEEN LESS
RAINFALL...AS LITTLE AS 0.50 INCHES.

FEBRUARY WAS GENERALLY WETTER THAN NORMAL ACROSS HSA WITH ROUGHLY
3 TO 6 INCHES OF PRECIPITATION OR 100 TO 200 PERCENT OF NORMAL.
THE WINTER AS A WHOLE WAS WET...WITH 13.78 INCHES VERSUS THE
30-YEAR NORMAL OF 9.72 INCHES OR 142 PERCENT OF NORMAL. FALL 2015
(SEP-NOV) WAS ALSO CONSIDERABLY WETTER THAN NORMAL WITH 17.25
INCHES VERSUS THE NORMAL OF 10.38 INCHES.

DROUGHT...

NONE.

SNOW COVER...

EXTREME WARMTH IN MARCH HAS ELIMINATED ALL SNOW.

PLEASE SEE WWW.NOHRSC.NOAA.GOV FOR DETAILED INFORMATION ON SNOW
COVER AND SNOW WATER EQUIVALENT.

RIVER ICE...

THERE IS NO RIVER ICE.

STREAMFLOW...

STREAMFLOWS AT BOTH SHORT DURATION (REAL-TIME AND 7-DAY AVERAGES)
AND LONGER DURATIONS (14-DAY AND 28-DAY AVERAGES) ARE RUNNING CLOSE
TO OR ABOVE NORMAL ACROSS THE ENTIRE HSA.

FOR MORE DETAILED INFORMATION ON STREAMFLOW CONDITIONS SEE THE USGS
WATERWATCH SITE BELOW.

HTTP://WATERDATA.USGS.GOV/?ID=WW_CURRENT

SOIL MOISTURE...

THE CPC SOIL MOISTURE RANKINGS STILL INDICATE ABOVE NORMAL SOIL
MOISTURE ACROSS NEARLY ALL OF THE BLACKSBURG HSA.

FOR ADDITIONAL INFORMATION FROM CPC: HTTP://WWW.CPC.NCEP.NOAA.GOV

THE UNIVERSITY OF WASHINGTON EXPERIMENTAL SOIL MOISTURE ANALYSIS
SHOWS SHRINKING AREA OF WETTER THAN NORMAL SOIL MOISTURE
CONDITIONS ACROSS THE CENTRAL PORTIONS OF THE BLACKSBURG
HSA...WITH MUCH OF THE AREA NOW IN THE NORMAL RANGE.

THIS DATA CAN BE ACCESSED AT:
HTTP://WWW.HYDRO.WASHINGTON.EDU/FORECAST/MONITOR/

RESERVOIRS...

ALL MAJOR RESERVOIRS SERVING THE HSA REMAIN NEAR OR ABOVE GUIDE
CURVES AND/OR CONSERVATION POOL LEVELS.

FUTURE WEATHER CONDITIONS...

PRECIPITATION FORECASTS FROM THE WEATHER PREDICTION CENTER (WPC)
OVER THE NEXT 7 DAYS SHOW GENERALLY 0.25 TO 0.75 INCHES DURING
THE PERIOD WHICH IS BELOW NORMAL AND NOT LIKELY TO CAUSE ANY
FLOODING.

LONGER TERM OUTLOOKS (6-10 AND 8-14 DAY) FROM THE CLIMATE PREDICTION
CENTER VALID THROUGH MARCH 26 AND MARCH 30 INDICATE A STRONG
PROBABILITY FOR ABOVE NORMAL TEMPERATURES. FOR PRECIPITATION THERE
ARE EQUAL CHANCES FOR ABOVE OR BELOW NORMAL IN THE 6-10 DAY RANGE
AND ELEVATED CHANCES FOR ABOVE NORMAL IN THE 8-14 DAY PERIOD.

PROBABILISTIC/ENSEMBLE RIVER FORECASTS...

PROBABILISTIC OUTLOOKS FROM THE METEOROLOGICAL MODEL ENSEMBLE
RIVER FORECAST (MMEFS) SYSTEM SHOW A LOW PROBABILITY (LESS THAN
30 PERCENT) OF ANY RIVER FORECAST POINT REACHING ACTION STAGE
OR HIGHER IN THE NEXT SEVEN DAYS.

ENSEMBLE RIVER FORECASTS (MMEFS) ARE AVAILABLE ON THE WEB AT:
WWW.WEATHER.GOV/ERH/MMEFS.

REPEATING THE CURRENT FLOOD POTENTIAL OUTLOOK: SLIGHTLY BELOW
NORMAL THROUGH THE TWO-WEEK PERIOD.

THIS IS THE FINAL SCHEDULED UPDATE OF THE WINTER/SPRING FLOOD
OUTLOOK IN 2016.

FOR ADDITIONAL WEATHER OR HYDROLOGIC INFORMATION...VISIT OUR
WEBSITE AT WWW.WEATHER.GOV/BLACKSBURG

$$

PC



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