Spring Flood Potential Outlook For Northern & Eastern Maine - 04/01/2021
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FGUS71 KCAR 012005
ESFCAR
MEC003-009-019-021-025-029-082015-
WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE CARIBOU ME
405 PM EDT THU APR 1 2021
..SPRING FLOOD POTENTIAL OUTLOOK FOR NORTHERN... CENTRAL...AND
DOWNEAST MAINE...
THIS IS THE SEVENTH WINTER/SPRING FLOOD POTENTIAL OUTLOOK FOR
2021, ISSUED BY THE NATIONAL WEATHER SERVICE IN CARIBOU, MAINE.
THIS OUTLOOK IS FOR NORTHERN, CENTRAL, AND DOWNEAST MAINE FOR THE
TWO-WEEK PERIOD OF APRIL 1ST TO APRIL 15TH 2021.
THE FLOOD POTENTIAL FOR OPEN WATER FLOODING IS NEAR NORMAL
ACROSS THE ENTIRE REGION. THE FLOOD POTENTIAL DUE TO ICE JAMS
REMAINS NEAR NORMAL ACROSS THE NORTHERN MAINE RIVERS, WHILE THE
THREAT FOR ICE JAM FLOODING ACROSS THE CENTRAL AND DOWNEAST AREAS.
NO THREAT OF ICE JAM FLOODING, WHILE THE DOWNEAST REGION REMAINS
BELOW NORMAL.
...CLIMATOLOGICAL GUIDANCE...
PRECIPITATION WAS BELOW NORMAL ACROSS THE SOUTHERN HALF OF THE
REGION WITH NO SNOWFALL REPORTED DURING THE LAST HALF OF THE
MONTH OF MARCH. NORTHERN AREAS REPORTED ABOVE NORMAL
PRECIPITATION DURING THE PERIOD WITH SNOWFALL BETWEEN 1 TO 3
INCHES FALLING ON THE 27TH AND 28TH.
TEMPERATURES AVERAGED ABOVE NORMAL DURING THE LAST HALF OF THE
MONTH OF MARCH. THIS HAS HELPED ACCELERATE THE SNOWMELT ACROSS THE
REGION AND IS RUNNING ABOUT 1 TO 2 WEEKS AHEAD OF SCHEDULE.
AN UPPER LEVEL BLOCKING RIDGE IS EXPECTED TO DEVELOP DOWNSTREAM
OF NEW ENGLAND LEADING TO A NEGATIVE NORTH ATLANTIC
OSCILLATION(NAO) PATTERN. THIS WILL ALLOW COLD AIR FROM CANADA TO
BE DIRECTED SOUTHWARD AROUND THE BLOCKING UPPER LEVEL RIDGE SOUTH
OF GREENLAND. THIS PATTERN IS EXPECTED TO HOLD RIGHT INTO THE
SECOND WEEK OF APRIL WITH TEMPERATURES NEAR TO SLIGHTLY BELOW
NORMAL FOR APRIL.
THE OFFICIAL NATIONAL WEATHER SERVICE 6 TO 14 DAY OUTLOOK IS
CALLING FOR NEAR TO SLIGHTLY BELOW NORMAL TEMPERATURES AND NEAR
TO SLIGHTLY BELOW NORMAL PRECIPITATION. SOME OF THE NUMERICAL
MODEL GUIDANCE IS SHOWING THAT THERE COULD BE A SHIFT IN THE
PATTERN TOWARD THE END OF THIS TERM, WHICH COULD ALLOW FOR A MORE
ACTIVE WEATHER PATTERN.
...OBSERVED SNOW DEPTH AND WATER EQUIVALENTS...
SNOW DEPTHS SAW A DRAMATIC DROP OVER THE LAST TWO WEEKS THANKS
TO THE WARMER TEMPERATURES AND RAINFALL. AS OF 8 AM THIS MORNING,
SNOW DEPTHS RANGED FROM 4 TO 10 INCHES ACROSS NORTHWEST MAINE,
WHICH INCLUDES THE ALLAGASH AND NORTH WOODS REGION. FURTHER EAST
ACROSS THE REST OF NORTHERN MAINE, SNOW DEPTHS RANGED FROM A TRACE
TO 4 INCHES WITH THE HIGHEST AMOUNTS IN THE WOODS AND ACROSS THE
HIGHER TERRAIN. ELSEWHERE, LITTLE IF ANY SNOW WAS LEFT ON THE
GROUND, WITH THE EXCEPTION OF SOME SNOW BANKS.
SNOW DEPTHS ARE WELL BELOW NORMAL FOR EARLY APRIL. AS STATED
ABOVE, THE WARMER TEMPERATURES OVER THE LAST TWO WEEKS
ACCELERATED THE SNOWMELT, WHICH IS RUNNING ABOUT TWO WEEKS AHEAD
OF SCHEDULE.
THE SNOW WATER EQUIVALENT, OR THE AMOUNT OF WATER CONTAINED IN
THE SNOWPACK, DECREASED OVER THE PAST TWO WEEKS ACROSS THE REGION.
AS OF 8 AM THIS MORNING, NORTHWEST MAINE HAD 2 TO 4 INCHES, WHILE
THE REST OF NORTHERN MAINE HAD UP TO 2 INCHES IN THE WOODS AND
HIGHER TERRAIN.
SNOW WATER EQUIVALENTS ARE WELL BELOW NORMAL ACROSS THE REGION.
THE FROST DEPTH AT NWS CARIBOU WAS AT 5 INCHES.
...SOIL MOISTURE AND WATER SUPPLY CONDITIONS...
THE LATEST PALMER DROUGHT SEVERITY INDEX, WHICH MEASURES SOIL
MOISTURE IN THE LONGER TERM, SHOWS NEAR NORMAL CONDITIONS FOR ALL
AREAS.
A LOOK AT THE GROUNDWATER LEVELS, COURTESY OF THE USGS, SHOWED
ABOVE NORMAL ACROSS NORTHERN AND NORTHWEST MAINE. THE CENTRAL
AREAS WERE SEEING NEAR TO SLIGHTLY ABOVE NORMAL, WHILE THE
DOWNEAST REGION SAW GROUNDWATER LEVELS IMPROVE TO ABOVE NORMAL.
CALAIS IN CENTRAL WASHINGTON REPORTED GROUNDWATER LEVELS WELL
ABOVE NORMAL.
...RIVER AND ICE CONDITIONS...
RIVER FLOWS WERE ABOVE NORMAL ACROSS NORTHERN AND CENTRAL AREAS,
WHILE THE DOWNEAST REGION WAS SEEING RIVER FLOWS NEAR NORMAL.
ICE COVER HAD BROKEN UP ACROSS THE RIVERS AND STREAMS THROUGHOUT
THE REGION, THANKS TO THE WARMER TEMPERATURES AND RAINFALL THAT
TOOK PLACE DURING THE LAST WEEK OF MARCH. THERE IS STILL SOME ICE
COVER ALONG THE ST. JOHN RIVER FROM LILLE TO HAMLIN WITH AN ICE
JAM IN PLACE JUST SOUTH OF LILLE. THE AROOSTOOK RIVER STILL HAS
ICE COVER IN THE VICINITY OF THE CARIBOU DAM, AND FROM THE
CARIBOU-FORT FAIRFIELD TOWN LINE ALL THE WAY TO THE INTERNATIONAL
BORDER AT TINKER DAM. THERE IS AN ICE JAM THAT IS STILL IN PLACE
IN FORT FAIRFIELD, FROM THE STRICKLAND ROAD TO THE FORT FAIRFIELD
BRIDGE.
...IN CONCLUSION...
THE FLOOD POTENTIAL FOR OPEN WATER FLOODING IS NEAR NORMAL ACROSS
THE ENTIRE REGION. THE FLOOD POTENTIAL DUE TO ICE JAMS REMAINS
NEAR NORMAL FOR THE NORTHERN MAINE RIVER BASINS. THE FLOOD
POTENTIAL FOR ICE JAM FLOODING FOR THE CENTRAL AND SOUTHERN AREAS
HAS ENDED FOR THE SEASON.
IT IS IMPORTANT TO REMEMBER THAT A HEAVY RAINFALL EVENT ALONG WITH
MILD TEMPERATURES, OR A PROLONGED WARMUP IN TEMPERATURES, CAN LEAD
TO AN INCREASED POTENTIAL FOR FLOODING WITH SNOWMELT AND RUNOFF.
ICE BREAKING UP AND JAMMING CAN ELEVATE THE THREAT FOR FLOODING IN
A SHORT PERIOD OF TIME.
THIS WILL BE THE LAST WINTER/SPRING FLOOD OUTLOOK ISSUED FOR THE
SEASON, UNLESS CONDITIONS WARRANT OTHERWISE.
$$
HEWITT
posted by Advackia at 11:59 AM
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