Nebraska Drought Monitor

000
FGUS73 KOAX 022309
ESFOAX
NEC003-023-025-039-053-055-067-095-107-109-119-127-139-141-147-151-
155-159-167-IAC071-085-133-137-145-155-291800-

PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
507 PM CST WED MAR 2 2011

...SPRING FLOOD AND WATER RESOURCES OUTLOOK NUMBER 3...

THIS OUTLOOK IS FOR THE OMAHA HYDROLOGIC SERVICE AREA /HSA/. THIS
OUTLOOK INCLUDES THE BIG BLUE...ELKHORN...PLATTE...LOUP AND MISSOURI
RIVERS AND THEIR TRIBUTARIES.

...AWAY FROM ICE JAM PRONE RIVERS THE POTENTIAL FOR SPRING FLOODING
IS GENERALLY NORMAL TO BELOW NORMAL...

.OVERVIEW...DURING THE WEEK OF FEBRUARY 13TH WELL ABOVE NORMAL
TEMPERATURES WERE OBSERVED ACROSS EASTERN NEBRASKA AND SOUTHWEST
IOWA. THIS RESULTED IN A MELT OF THE ENTIRE SNOWPACK. THESE WARM
TEMPERATURES ALSO RESULTED IN A MAJORITY OF THE ICE ON AREA RIVERS
TO BREAKUP AND MOVE DOWNSTREAM. WHILE SOME ICE JAM FLOODING WAS
OBSERVED...FOR THE MOST PART IT WAS MINOR. THE THREAT FOR ICE JAMS
THOUGH REMAINS. ICE CAN STILL BE FOUND IN THE PLATTE/ELKHORN AND
LOUP RIVERS. IN HOWARD...POLK AND MERRICK COUNTIES THIS ICE HAS
RECENTLY CAUSED MINOR FLOODING. UNTIL ALL OF THIS ICE EITHER MELTS
OR MOVES DOWNSTREAM...THE THREAT FOR ICE JAM FLOODING CONTINUES.

THE TABLE BELOW SHOWS THE CHANCE OF FLOODING FOR SELECT RIVERS
COMPARED TO NORMAL.

                        DEPARTURE FROM
                           NORMAL
                         OF REACHING
    LOCATION             FLOOD STAGE
--------------------------------------

** = INDICATES AN ABOVE NORMAL CHANCE.

BIG BLUE R AT
    SURPRISE NO.1         -10% LESS
    SEWARD                -14% LESS
    CRETE 2S              -21% LESS
    BEATRICE              -21% LESS
    BARNESTON             -10% LESS

LITTLE BLUE NEAR
    FAIRBURY              -10% LESS

LINCOLN CR
    SEWARD 3WNW           -17% LESS

W FK BIG BLUE R
    DORCHESTER 7NW        -23% LESS

TURKEY CR
    WILBER 3W             -18% LESS

PONCA CR
    VERDEL 1E             NEAR NORMAL

N FK ELKHORN R
    PIERCE 2SE**          36% GREATER

ELKHORN R
    WEST POINT 1W**        6% GREATER
    HOOPER                NEAR NORMAL

SHELL CR
    COLUMBUS 8NE**         8% GREATER

SALT CR
    ROCA                  -6% LESS
    LINCOLN               NEAR NORMAL
    GREENWOOD 1WNW        NEAR NORMAL
    ASHLAND NO.1          -7% LESS

WAHOO CR
    ITHACA**               6% GREATER

BOYER R
    LOGAN                 NEAR NORMAL

WEEPING WATER CREEK
    UNION                 NEAR NORMAL

EAST NISHNABOTNA R
    ATLANTIC IA 5SW       NEAR NORMAL
    RED OAK IA #2**        9% GREATER

NISHNABOTNA R
    HAMBURG IA 2NE        NEAR NORMAL

LITTLE NEMAHA R
    AUBURN NE 1NE**        9% GREATER

BIG NEMAHA R
    FALLS CITY NE 2NE      -6% LESS

NODAWAY R
    CLARINDA IA 1E        NEAR NORMAL

LITTLE SIOUX R
    TURIN IA 4S**         12% GREATER

** = INDICATES AN ABOVE NORMAL CHANCE
--------------------------------------

.HYDROLOGIC CONDITIONS AS OF MARCH 2ND 2011...

.SNOW PACK...NO SIGNIFICANT SNOWPACK REMAINS IN THE AREA.

.STREAM LEVELS/SOIL MOISTURE...BOTH OF THESE REMAIN HIGH. THESE
ELEVATED LEVELS ARE THE REMNANTS OF THE ABOVE NORMAL PRECIPITATION
OBSERVED LAST YEAR.

.DROUGHT...PORTIONS OF SOUTH CENTRAL NEBRASKA CONTINUE TO BE
CLASSIFIED AS ABNORMALLY DRY. WITHOUT A SIGNIFICANT PRECIPITATION
EVENT...THESE ABNORMALLY DRY CONDITIONS WILL PROGRESS FURTHER NORTH
IN NEBRASKA AS WELL AS INTO AREAS OF SOUTHWESTERN IOWA.

.FROST DEPTH...DEPTHS RANGE FROM 5 TO 9 INCHES.

.WEATHER AND CLIMATE OUTLOOK...

LA NINA CONDITIONS CONTINUE IN THE PACIFIC OCEAN...AND ARE EXPECTED
TO CONTINUE AT LEAST THROUGH LATE SPRING.  AFTER THAT
TIME...CONFIDENCE IS LOW IN FORECASTING WHETHER THE LA NINA WILL
PERSIST THROUGH THE SUMMER OR CONDITIONS WILL RETURN TO A NEUTRAL
STATE.  IN GENERAL...LA NINAS ARE ASSOCIATED WITH A HIGHER THAN
USUAL CHANCE FOR DRIER THAN NORMAL CONDITIONS IN THE CENTRAL
PLAINS...AS WELL AS A HIGHER THAN USUAL CHANCE FOR CONDITIONS THAT
FAVOR THE POTENTIAL FOR TORNADO ACTIVITY.  THE LONGER THAT THE LA
NINA PERSISTS AND THE STRONGER IT REMAINS...THE MORE THAT IT CAN
IMPACT WEATHER ACROSS THE CENTRAL US.

COMPARED TO THE 1971-2000 CLIMATE PERIOD....THE 8 TO 14-DAY OUTLOOK
INDICATES A 40 TO 50 PERCENT CHANCE FOR TEMPERATURES IN THE COLDEST
THIRD OF THE RECORD AND A 33 TO 40 PERCENT CHANCE OF CONDITIONS IN
THE WETTEST THIRD OF THE RECORD.

THE THREE-MONTH OUTLOOK FOR MARCH THROUGH MAY INDICATES EQUAL
CHANCES FOR TEMPERATURES TO BE BELOW...NEAR...OR ABOVE NORMAL.  THE
OUTLOOK DOES INDICATE A 33 TO 40 PERCENT CHANCE OF CONDITIONS IN THE
DRIEST THIRD OF THE RECORD COMPARED TO 1971-2000 CLIMATOLOGY ACROSS
ALL OF EASTERN NEBRASKA AND WESTERN IOWA...ASSOCIATED WITH THE
PERSISTENT LA NINA.

$$

PEARSON/MAYES