HYDROLOGIC OUTLOOK... NATIONAL WEATHER SERVICE LITTLE ROCK AR 200 PM CST FRI MAR 10 2006
...ANNUAL SPRING FLOOD OUTLOOK FOR NWS LITTLE ROCK HYDROLOGIC SERVICE AREA...
...CHANCES FOR SPRING FLOODING IN ARKANSAS ARE BELOW AVERAGE...
INTRODUCTION... THIS IS THE INITIAL 2006 SPRING FLOOD OUTLOOK ISSUED BY THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN LITTLE ROCK ARKANSAS. THE GOAL OF THIS PRODUCT IS TO OUTLINE CURRENT RIVER...LAKE...AND SOIL MOISTURE CONDITIONS AND POINT OUT ANY EXTRAORDINARY SITUATIONS OR FORECAST THAT COULD MORE READILY INDUCE FLOODING OR EXACERBATE DROUGHT.
ANTECEDENT CONDITIONS... MARCH 8TH AND 9TH...A NARROW BAND OF 2 TO 4 INCHES OF RAIN FELL BETWEEN DANVILLE IN YELL COUNTY UP TOWARD THE BOOTHEEL OF MISSOURI. OVERALL...RAINFALL IN ARKANSAS FOR THE YEAR TO DATE IS GENERALLY AT 60 TO 90 PERCENT OF NORMAL. HOWEVER...LONG TERM RAINFALL AMOUNTS REMAIN WELL BELOW NORMAL. THE YEAR 2005 ENDED AS ONE OF THE DRIER YEARS OF RECORD FOR THE STATE. RAINFALL DEFICITS WERE GENERALLY 10 AND 25 INCHES BELOW NORMAL. NORMAL RAINFALL RANGES BETWEEN 48 AND 52 INCHES PER YEAR. WILDFIRES WERE A PROBLEM EARLY THIS YEAR...WITH MORE ACRES BURNING IN JANUARY 2006 THAN HAVE BURNED IN THE LAST 10 YEARS COMBINED. STATE FORESTRY OFFICIALS STATED THAT THE JANUARY BURN AREA WAS OVER 10000 ACRES. RECENT RAINFALL HAS LESSENED THE FIRE DANGER...BUT SOIL MOISTURE REMAINS WELL BELOW NORMAL. SOUTHWESTERN ARKANSAS COUNTIES RANKED IN THE 1ST PERCENTILE OF SOIL MOISTURE AT THE END OF FEBRUARY. EASTERN AND SOUTHEASTERN COUNTIES RANKED BETWEEN THE 20TH TO 30TH PERCENTILE. ARKANSAS NEEDS A LONG TERM PERIOD OF ABOVE NORMAL RAINFALL TO RECOVER FROM THE DROUGHT.
HYDROLOGIC CONDITIONS... CURRENTLY...THERE IS MINOR FLOODING IN THE NORTHEASTERN BASINS OF THE STATE. SPECIFICALLY...THE SPRING...BLACK...AND CACHE RIVERS ARE FLOWING AT LEVELS NEAR OR ABOVE FLOOD LEVEL. OTHERWISE...MOST WATERWAYS OF THE STATE ARE WELL BELOW NORMAL FOR THE LATE WINTER AND EARLY SPRING PERIOD. CURRENT STREAMFLOW CONDITIONS WOULD TEND TO INDICATE A LESS THAN NORMAL THREAT FOR FLOODING. THE ARKANSAS RIVER HAS BEEN FLOWING AT A RATE OF LESS THAN 5000 CUBIC FEET PER SECOND FOR MOST OF THE WINTER AND POSSIBLY AS LOW AS 1000 CUBIC FEET PER SECOND FOR SEVERAL DAYS. THE LARGE MULTIPURPOSE CORPS OF ENGINEERS RESERVOIRS IN BOTH THE WHITE AND OUACHITA RIVER BASINS ARE WELL BELOW TOP OF CONSERVATION STORAGE. LAKES SUCH AS BULL SHOALS...BEAVER...NORFORK...AND OUACHITA ARE 10 TO 15 FEET LOW. FLOOD CONTROL STORAGE CAN BE CONSIDERED TO BE WELL ABOVE 100 PERCENT SINCE FULL FLOOD CONTROL STORAGE PLUS THE CONSERVATION DEFICITS ARE AVAILABLE FOR HOLDING BACK HEAVY RAINFALL. AT LEAST 2 OF THE LARGER MUNICIPAL WATER SUPPLIERS IN THE STATE ARE SEEKING ALTERNATIVE WATER SUPPLIES DUE TO LOW RESERVOIR LEVELS.
CLIMATIC OUTLOOK... NEAR TERM OUTLOOK CALLS FOR RAIN CHANCES OVER THE WEEKEND. LONG RANGE OUTLOOK FOR THE NEXT 30 TO 90 DAYS IS FOR EQUAL CHANCES FOR NORMAL RAINFALL. LA NINA CONDITIONS HAVE DEVELOPED WHICH CLIMATICALLY TREND TOWARDS LESS THAN NORMAL RAINFALL DURING THE SPRING AND NEAR...TO ABOVE NORMAL RAINFALL IN THE SUMMER MONTHS.
CONCLUSION... THE FLOOD THREAT IN ARKANSAS THIS SPRING APPEARS TO BE BELOW AVERAGE. HEAVY RAINFALL DURING A DROUGHT CAN CAUSE FLASH FLOODING AND EVEN SHORT TERM MINOR RIVER FLOODING IN THE SMALLER RIVER BASINS. HOWEVER...CURRENT CONDITIONS DO NOT APPEAR FAVORABLE FOR RIVER FLOODING THAT IS EITHER OF A LONG DURATION OR THAT WOULD BE UNUSUALLY HIGH.
ANNUALLY...THERE IS ALWAYS THE POTENTIAL FOR DELAYED SPRING PLANTING IN SOME OF THE MORE FLOOD PRONE LOWLANDS. INTENSE THUNDERSTORM RAINFALL COULD INDUCE FLASH FLOODING ALONG SMALL WATERSHEDS AND POORLY DRAINED AREAS. THIS IS ESPECIALLY TRUE FOR HIGHLY URBANIZED AREAS.
CONDITIONS CAN CHANGE RAPIDLY. IF FLOODING APPEARS MORE LIKELY...THIS PRODUCT WILL BE UPDATED WITH SPECIFIC THREATS OUTLINED.
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