199
NOUS43 KFGF 181744 CCA
PNSFGF
PUBLIC INFORMATION STATEMENT...CORRECTED
NATIONAL WEATHER SERVICE GRAND FORKS ND
200 PM CST TUE NOV 17 2009
WINTER 2009/2010 OUTLOOK AND POSSIBLE SPRING 2010 FLOOD IMPACTS
AS OUR DAMP NORTHERN PLAINS AUTUMN TURNS TO THOUGHTS OF AN EL NINO
AFFECTED WINTER...LOCAL FORECASTERS THOUGHTS ALSO TURN TO SPRING AND
THE PROSPECTS FOR FLOODING.
THE RECORD FLOODING OF SPRING 2009 IS STILL A FAIRLY FRESH MEMORY...
AND THOUGH THOSE FLOOD WATERS HAVE RECEDED...TOP SOIL CONDITIONS
ACROSS THE RED RIVER BASIN HAVE BEEN SLOW TO DRY OUT. SUMMER SEASON
PRECIPITATION GENERALLY DECREASED AFTER THE MARCH-APRIL FLOODS...BUT
UNSEASONABLY COOL WEATHER AND EXCESSIVE CLOUD COVER DURING THE
SUMMER MONTHS OF JUNE...JULY AND AUGUST HELPED KEEP THE SOILS MOIST.
RAINFALL THROUGH THE LATE FALL OF 2009 HAS HELPED MAINTAIN THIS
OVERLY-WET GROUND WATER CONDITION AND HELPED TO KEEP OUR RIVER BASE
FLOWS QUITE HIGH. THIS EXCESS WATER REMAINS A THREAT WHICH COULD
AFFECT OUR NEXT SPRING FLOOD. EXPECTED WARMER AND SOMEWHAT DRIER
CONDITIONS THIS WINTER COULD ACT TO REDUCE THAT OVERALL FLOOD
THREAT.
FALL SOIL CONDITIONS ARE QUITE WET. THE VERY BRIEF RESPITE FROM
ABOVE AVERAGE PRECIPITATION THIS SUMMER WAS NOT LONG ENOUGH TO ALLOW
THE RIVER SYSTEM TO FULLY DRAIN THE EXCESS MOISTURE...NEITHER IN
SURFACE STORAGE AREAS NOR IN THE SOIL PROFILE.
GROUND CONDITIONS IN THE SOUTHERN COUNTIES OF EASTERN NORTH DAKOTA
BARNES...CASS...RANSOM..SARGENT AND RICHLAND ARE VERY WET. THE SAME
IS TRUE FOR PORTIONS WEST CENTRAL MINNESOTA INCLUDING WILKIN...CLAY
...OTTERTAIL AND BECKER. SOILS IN MANY PARTS OF THESE COUNTIES ARE
SATURATED AND SURFACE STORAGE AREAS ARE FULL. RUNOFF RATES FROM
RAINS IN THE LAST WEEK OF OCTOBER WERE EXTREMELY HIGH...CONTRIBUTING
GREATLY TO THE LATE SEASON FLOODING THAT OCCURRED ON THE WILD RICE
AT ABERCROMBIE AND RED RIVER IN FARGO. ACCORDING TO THE USGS OFFICE
IN BISMARCK...THIS IS THE HIGHEST PEAK ON THE RED IN FARGO SO LATE
IN THE YEAR.
SEE HTTP://WWW.USGS.GOV/NEWSROOM/ARTICLE.ASP?ID=2344
SOIL CONDITIONS IN THE MIDDLE COUNTIES OF EASTERN NORTH DAKOTA
NELSON...GRAND FORKS...GRIGGS...STEELE AND TRAILL AS WELL AS THE
NORTHWEST MINNESOTA COUNTIES OF NORMAN AND POLK ARE A BIT BETTER
OFF...BUT STILL VERY WET...WITH LITTLE ROOM FOR ADDITIONAL WATER IN
THE SOILS AND SURFACE STORAGE AREAS. GROUND CONDITIONS IN THE
NORTHERN COUNTIES CAVALIER...PEMBINA AND WALSH...AND THE NORTHWEST
MINNESOTA COUNTIES OF KITTSON AND MARSHALL ARE A BIT BETTER OFF DUE
TO LESSER RAINS DURING THE LATE SUMMER AND AUTUMN.
DESPITE THE WET OCTOBER...THE OVERALL CONDITIONS DURING THE SUMMER
AND EARLY FALL OF 2009 HAVE BEEN CONSIDERABLY DRIER THAN 2008. YET
DUE TO THE WET CONDITIONS...TIMING AND AMOUNTS OF THE FALL RAIN...
TOPSOIL AND SUBSOIL CONDITIONS ARE VERY SIMILAR TO THOSE FOUND IN
THE FALL OF 2008.
LAST FALL THE FREEZE-UP TOOK PLACE EARLY AND QUICKLY...FROM NOVEMBER
8TH THROUGH 10TH 2008. THIS LED TO THE SATURATED TOP SOILS BECOMING
A HARD...CONCRETE FROST. THESE CONDITIONS PREVAILED THROUGHOUT THE
WINTER AND INTO THE SPRING OF 2009. THE FREEZE-UP HAS NOT OCCURRED
YET THIS FALL...AND THE FORECASTS ARE NOT SUGGESTING THIS WILL
HAPPEN UNTIL AFTER LATE-NOVEMBER.
WINTER OUTLOOK POINTS TO WARMER AND DRIER CONDITIONS. THIS WINTER
SEASON LOOKS LIKE IT WILL BE A BIT DIFFERENT THAN LAST YEARS. DURING
THE SUMMER OF 2009...AN EL NINO DEVELOPED AND HAS CONTINUED
THROUGHOUT THE FALL. DURING TYPICAL EL NINO WINTERS...TEMPERATURES
FOR OUR REGION ARE 2 TO 4 DEGREES ABOVE NORMAL...AND SNOWFALL TENDS
TO BE 75% TO 80% OF NORMAL. WHILE THERE ARE OTHER LARGE SCALE
CLIMATE SIGNALS THAT CAN DECREASE THE AFFECT OF THE EL NO...THE
WINTER OF 2009/2010 IS EXPECTED TO BE WARMER AND DRIER THAN LAST
YEAR.
CLASSIC EL NINO WINTERS FEATURE LESS FREQUENT ARCTIC AIR INTRUSIONS
AND FEWER SNOW STORMS. EXAMPLES OF RECENT EL NINO WINTERS INCLUDE
2006/2007...2002/2003...1997/1998...1994/1995 AND 1991/1992. BELOW
IS A TABLE WITH THE AVERAGE SNOWFALL FOR FARGO AND THE UNIVERSITY OF
NORTH DAKOTA/NWS CLIMATE STATION AND EL NINO AVERAGE SNOWFALL.
STATION SEASONAL
SNOWFALL SEASON 1971-2000
1987/88 1991/92 1994/95 1997/98 2002/03 2006/07 AVERAGE NORMAL
FARGO 44.5 27.5 50.3 41.1 33.4 38.3 39.1 48.7
GRAND FORKS 31.6 33.4 37.9 45.3 34.1 47.3 38.3 44.5
OVERALL...THERE TENDS TO BE SLIGHTLY LESS SNOW DURING EL NINO WINTER.
TYPICALLY...THE SNOWS DO NOT BUILD UP AS MUCH AS THE WARMER
TEMPERATURES OFTEN MELT THE SNOW BETWEEN STORMS. THIS PREVENTS THE
SNOW FROM ACCUMULATING TO AVERAGE DEPTHS.
WINTER SEASON TEMPERATURES TEND TO BE WARMER ACROSS THE NORTHERN
PLAINS DURING AN EL NINO. BELOW IS A TABLE OF THE SAME 6 SEASONS
EXCEPT THE DECEMBER THROUGH FEBRUARY AVERAGE TEMPERATURES ARE
COMPARED TO NORMAL.
STATION
SEASON AVERAGE SEASON 1971-2000
1987/88 1991/92 1994/95 1997/98 2002/03 2006/07 AVERAGE NORMAL
FARGO 11.9 19.9 14.6 20.9 12.5 15.0 15.8 11.2
GRAND FORKS 11.9 18.1 13.2 19.5 11.3 12.4 14.4 10.5
SPRING 2010 FLOOD THREAT COULD BE SOMEWHAT REDUCED. ALTHOUGH IT IS
WAY TOO SOON TO PROVIDE A RELIABLE SPRING FLOOD OUTLOOK THE
PROSPECTS FOR AN EL NINO AFFECTED WINTER COULD HELP TO MITIGATE THE
EFFECTS OF OUR OTHERWISE WET SOIL CONDITIONS AND HIGH RIVER BASE
FLOWS.
BELOW IS A TABLE OF CRESTS ON THE RED RIVER AT FARGO AND GRAND FORKS
.THE FOLLOWING SPRING...FOR THE EL NINO YEARS
AS LISTED ABOVE.
STATIONSPRING CREST
198819921995199820032007
FARGO 15.1 15.8 28.4 28.9 22.6 21.9
GRAND FORKS 21.2 23.3 39.7 39.8 18.1 36.6
CAVEATS...THE LARGER UNKNOWNS AT THIS TIME INCLUDE THE POTENTIAL FOR
SIGNIFICANT RAINS NEAR THE TIME OF THE SPRING SNOW-MELT...OR ANY
LATE-SEASON...WET AND HEAVY SNOWFALLS THAT COULD COMPLICATE THE
SPRING 2010 SNOW-MELT SCENARIO. ANOTHER SIGNIFICANT VARIABLE IS THE
EVENTUAL STRENGTH AND DURATION OF THE EL NINO. SHOULD THIS EL NINO
WEAKEN RAPIDLY AS IT DID IN 2006/2007...THE THREAT FOR SIGNIFICANT
SPRING PRECIPITATION WOULD INCREASE. SHOULD THE EL NINO CONTINUE
INTO THE SPRING OF 2010...TEMPERATURES WOULD LIKELY REMAIN ABOVE
NORMAL AND PRECIPITATION BELOW NORMAL. YOUR NWS WILL MONITOR THE EL
NINO AND UPDATE THE IMPACT ASSESSMENT MID-WINTER.
IN SUMMARY...GIVEN THE PERSISTENT WET CONDITIONS ACROSS THE BASIN
THIS FALL...THERE IS CERTAINLY A POTENTIAL FOR A SIGNIFICANT FLOOD
IN THE SPRING OF 2010. HOWEVER...WE ARE NOW IN AN EL NINO PATTERN
WHICH DOES TEND TO FAVOR WARMER AND SLIGHTLY DRIER WINTERS IN OUR
REGION...AND WHICH SHOULD HELP TO REDUCE THE THREAT FOR SIGNIFICANT
SNOWMELT FLOODING NEXT SPRING. THE NWS WILL BE CLOSELY MONITORING
THE WINTER WEATHER CONDITIONS AS WE PREPARE OUR SPRING FLOOD
OUTLOOKS LATER THIS YEAR. KEEP IN MIND THAT A WET FALL IS ONLY ONE
FACTOR CONSIDERED FOR THE EVENTUAL SNOWMELT RUNOFF AND SPRING RIVER
CONDITIONS.
SEE THE FOLLOWING LINK FOR A DISCUSSION OF THE OTHER FACTORS WHICH
AFFECT FLOODING ON THE RED RIVER OF THE NORTH AND ITS TRIBUTARIES:
WWW.DMR.ND.GOV/NDGS/NEWSLETTER/NL01S/PDF/MORES01.PDF
STREAMFLOW DURATION GRAPHS FOR THE RED RIVER ARE ANOTHER WAY TO VIEW
THE CURRENT AND RECENT RIVER FLOWS COMPARED TO HISTORICAL AVERAGES.
THESE STREAMFLOW DURATION HYDROGRAPHS ARE AVAILABLE AT
FARGO ND
HTTP://WATERDATA.USGS.GOV/NWIS/UV?SITE_NO=05054000
GRAND FORKS ND
HTTP://WATERDATA.USGS.GOV/NWIS/UV?SITE_NO=05082500
DRAYTON ND
HTTP://WATERDATA.USGS.GOV/NWIS/UV?SITE_NO=05092000
FOR MORE INFORMATION PLEASE CONTACT THE GRAND FORKS NATIONAL WEATHER
SERVICE AT 701.772.0720 X627 OR CONTACT
MIKE LUKES, SERVICE HYDROLOGIST AT MIKE.LUKES@NOAA.GOV
MARK EWENS, DATA ACQUISITION PROGRAM MANAGER AT MARK.EWENS@NOAA.GOV
..CORRECTED FOR TYPOGRAPHICAL ERRORS
ME/MML/GG
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