SPRING FLOOD OUTLOOK FOR MT EAST OF THE DIVIDE RELEASED.

NATIONAL WEATHER SERVICE GREAT FALLS MT
1209 PM MST FRI FEB 19 2010

...SPRING FLOOD OUTLOOK FOR MONTANA EAST OF THE CONTINENTAL DIVIDE...

...BELOW AVERAGE POTENTIAL FOR FLOODING FROM SPRING RUNOFF FOR
MONTANA EAST OF THE CONTINENTAL DIVIDE...

INTRODUCTION...
BASED ON THE CURRENT SNOWPACK IN THE MOUNTAINS AND SNOW COVER ON THE
PLAINS OF MONTANA...LITTLE OR NO FLOODING IS EXPECTED. 

ABOVE NORMAL SPRING SNOW ACCUMULATIONS...HEAVY RAINS...RAPID MELT
AND/OR ICE JAMS WILL INCREASE THE CURRENT FLOOD POTENTIAL. BELOW
NORMAL SPRING PRECIPITATION AND GRADUAL OR INTERMITTENT FREEZING AND
THAWING WILL DECERASE THE FLOOD POTENTIAL. 

CURRENT SOIL MOISTURE CONDITIONS...
ACCORDING TO THE PALMER DROUGHT SEVERITY INDEX...SOIL MOISTURE
THROUGHOUT MUCH OF MONTANA IS ABOVE OR NEAR NORMAL. THE EXCEPTION
WOULD BE PARTS OF SOUTHERN MONTANA THAT HAVE NEAR NORMAL TO SLIGHTLY
BELOW NORMAL SOIL MOISTURE. MEASUREMENTS INDICATE THE GROUND IS
FROZEN TO DEPTHS RANGING FROM AROUND ONE HALF FOOT IN PORTIONS OF
CENTRAL MONTANA TO 4 FEET IN NORTHEAST MONTANA.

CURRENT RIVER CONDITIONS...
MANY RIVERS IN MONTANA REMAIN ICED OVER. GIVEN THE SHORT-TERM
TEMPERATURE FORECASTS FOR THE NEXT SEVERAL DAYS...IT IS NOT LIKELY
SIGNIFICANT THAWING OF RIVER ICE WILL OCCUR IN THE IMMEDIATE FUTURE.

CURRENT SNOW CONDITIONS...
THERE IS VERY LITTLE SNOW ON THE PLAINS WITH THE EXCEPTION OF THE FAR
EASTERN TIER OF COUNTIES. MOST OF CENTRAL MONTANA HAS LESS THAN AN
INCH OF WATER EQUIVALENT WITH SNOW DEPTHS RANGING FROM 3 TO 7
INCHES. EASTERN MONTANA HAS 10 TO 15 INCHES OF SNOW ON THE GROUND
AND TWO INCHES OF SNOW WATER EQUIVALENT.

BASIN SNOWPACK IN THE MOUNTAINOUS AREAS OF MONTANA GENERALLY RANGES
FROM ABOUT 70 PERCENT TO 85 PERCENT OF AVERAGE. LOWEST OVERALL
SNOWPACK IS IN THE SUN/TETON/MARIAS RIVER BASIN COMPLEX WHICH IS 58
PERCENT OF AVERAGE BASIN-WIDE. HIGHEST OVERALL SNOWPACK IS IN THE
SMITH/JUDITH/MUSSELSHELL RIVER BASIN COMPLEX WHICH IS 100 PERCENT OF
AVERAGE BASIN-WIDE.

BY LATE FEBRUARY...MONTANA IS APPROXIMATELY THREE-QUARTERS OF THE WAY
THROUGH THE MAIN SNOWFALL PERIOD. THERE ARE STILL FOUR TO SIX WEEKS
REMAINING UNTIL THE SEASONAL SNOWPACK PEAK IS REACHED.

LOOKING AHEAD...LITTLE CHANGE IN THE GENERAL WEATHER PATTERN IS EXPECTED WITH NO
SIGNIFICANT WARM UP INDICATED AND NO SIGNIFICANT PRECIPITATION
EVENTS FORECASTED FOR MONTANA EAST OF THE CONTINENTAL DIVIDE THROUGH
THE 8 TO 14 DAY FORECAST PERIOD. THE OUTLOOK FOR MARCH SHOWS EQUAL
CHANCES FOR ABOVE...BELOW OR NEAR NORMAL TEMPERATURES AND
PRECIPITATION. THE OUTLOOK FOR THE MARCH THROUGH MAY PERIOD SHOWS
SLIGHTLY BETTER CHANCES FOR ABOVE NORMAL TEMPERATURES WITH EQUAL
CHANCES FOR ABOVE...BELOW OR NEAR NORMAL PRECIPITATION.

THE NEXT SPRING FLOOD POTENTIAL OUTLOOK FOR MONTANA WILL BE ISSUED MARCH 5 2010.

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