Flood Potential Outlook
Issued by NWS Caribou, ME

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1
000
FGUS71 KCAR 161753
ESFCAR
MEZ001>006-010-011-015>017-029>032-181800-

WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE CARIBOU ME
153 PM EDT THU APR 16 2015

...WINTER/SPRING FLOOD POTENTIAL OUTLOOK FOR NORTHERN...
CENTRAL...AND DOWNEAST MAINE...

THIS IS THE NINTH WINTER/SPRING FLOOD POTENTIAL OUTLOOK FOR
2015...ISSUED BY THE NATIONAL WEATHER SERVICE IN CARIBOU, MAINE.
THIS OUTLOOK IS FOR NORTHERN, CENTRAL AND DOWNEAST MAINE FOR THE
TWO-WEEK PERIOD FROM APRIL 16 THROUGH APRIL 30, 2015.

THE WINTER/SPRING FLOOD POTENTIAL FOR OPEN WATER FLOODING FOR THE
CENTRAL MAINE HIGHLANDS SOUTH TO THE COAST IS ABOVE NORMAL. FOR
NORTHERN MAINE, THE OPEN WATER FLOOD POTENTIAL IS NEAR NORMAL.

THE POTENTIAL FOR FLOODING DUE TO ICE JAMS IS ABOVE NORMAL FOR
NORTHERN MAINE, ESPECIALLY THE AROOSTOOK, SAINT JOHN, AND
ALLAGASH RIVER BASINS. A LOT OF THE ICE HAS FLUSHED OUT OF THE
PISCATAQUIS AND PENOBSCOT BASINS, SO THE ICE JAM FLOOD POTENTIAL
IN THESE AREAS IS BELOW NORMAL, THOUGH NOT COMPLETELY OVER.

...CLIMATOLOGICAL GUIDANCE...

WE HAVE FINALLY SEEN A HINT OF SPRING HERE IN MAINE OVER THE PAST
COUPLE OF WEEKS. TEMPERATURES HAVE FINALLY WARMED INTO THE 50S AND
60S WITH PLENTIFUL SUNSHINE. THIS HAS ALLOWED FOR A LOT OF
SNOWMELT AND WEAKENING OF RIVER ICE.

UNFORTUNATELY, WE ARE SEEING SIGNS THAT THE WEATHER PATTERN IS
GOING TO CHANGE BACK TO A COOLER, MORE ACTIVE ONE. LONGER RANGE
MODELS SUGGEST THAT THERE WILL BE RIDGING ACROSS THE WESTERN
UNITED STATES WITH TROUGHING DEVELOPING IN THE EAST. THIS GIVES AN
INCREASED THREAT FOR A CUTOFF LOW, WHICH WOULD GIVE A PROLONGED
RAIN EVENT. THE JET STREAM PATTERN WILL BECOME MORE ACTIVE AND
COMPLEX, AND DEPENDING ON PHASING, ANY STORM SYSTEM THAT DEVELOPS
COULD INTERACT WITH SUBTROPICAL MOISTURE. THIS SETUP COULD YIELD
THE POTENTIAL FOR ONE OR TWO SIGNIFICANT PRECIPITATION EVENTS FOR
THE LATTER HALF OF APRIL. AT THIS TIME, WE DON`T SEE ANY
SIGNIFICANT PRECIPITATION IN THE NEAR FUTURE FOR OUR FORECAST
AREA; JUST SOME MINOR RAINFALL EVENTS FOR FRIDAY THROUGH THE
WEEKEND. WITH TEMPERATURES RETURNING TO COOLER READINGS, THIS RAIN
MAY EVEN MIX WITH SNOW OVER NORTHERN MAINE. HOWEVER, LONGER RANGE
MODELS ARE INDICATING THAT A MORE SIGNIFICANT PRECIPITATION EVENT
IS POSSIBLE HEADING INTO THE MIDDLE PART OF NEXT WEEK.

THE OFFICIAL NATIONAL WEATHER SERVICE 6 TO 14 DAY OUTLOOK FOR
APRIL 21 THROUGH APRIL 29 SUPPORTS THE ABOVE THINKING WELL,
CALLING FOR BELOW NORMAL TEMPERATURES AND ABOVE NORMAL
PRECIPITATION THROUGH THE LAST PART OF APRIL.

...OBSERVED SNOW DEPTH AND WATER EQUIVALENTS...

THE MILD TEMPERATURES WE`VE SEEN OVER THE PAST SEVERAL DAYS HAS
ALLOWED COPIOUS AMOUNTS OF SNOWMELT AND RESULTANT RUNOFF. WE HAVE
LOST A SIGNIFICANT PART OF OUR SNOWPACK; SOME LOCATIONS HAVE LOST
A FOOT OR MORE OF DEPTH IN THE PAST TWO WEEKS. THE DEEPEST SNOW
IS ACROSS THE HIGHER TERRAIN OF THE NORTH MAINE WOODS, WHERE THE
PACK IS STILL 1.5 TO 2 FEET DEEP. THIS DECREASES AS ONE HEADS
SOUTH AND EAST, WITH MOST LOCATIONS REPORTING 8 TO 18 INCHES OVER
THE EASTERN HALF OF THE FORECAST AREA. COASTAL HANCOCK COUNTY HAS
LESS THAN 6 INCHES OF SNOW ON THE GROUND, BUT CENTRAL AND COASTAL
WASHINGTON COUNTY LOCATIONS ARE STILL REPORTING UP TO 2 FEET.

THE SNOW WATER EQUIVALENT, OR THE AMOUNT OF WATER CONTAINED IN
THE SNOWPACK, IS STILL ABOVE NORMAL ALONG AND SOUTH OF A DANFORTH
TO DOVER-FOXCROFT LINE. THESE LOCATIONS ARE REPORTING 4 TO 7
INCHES OF WATER IN THEIR SNOW, WITH CLOSER TO 3 INCHES IN THE
BANGOR REGION. THE HIGHEST AMOUNT OF WATER IS IN THE NORTH MAINE
WOODS, WHERE 5 TO 8 INCHES IS BEING REPORTED. FOR FAR NORTHERN AND
EASTERN AROOSTOOK COUNTY, THERE IS STILL 3 TO 6 INCHES OF WATER IN
THE PACK. THE SNOW IS NOW VERY RIPE, WITH NEARLY THE ENTIRE AREA
REPORTING DENSITIES OF AT LEAST 30 PERCENT. THIS MEANS THAT ANY
SNOW ON THAT STILL COVERS THE GROUND WILL BE ABLE TO ABSORB LITTLE
TO NO ADDITIONAL WATER.

...SOIL MOISTURE AND WATER SUPPLY CONDITIONS...

NOW THAT WE`VE SEEN SOME SNOWMELT AND RUNOFF, NEAR-SURFACE SOIL
MOISTURE STATES HAVE IMPROVED TO NEAR NORMAL. THE LATEST PALMER
DROUGHT SEVERITY INDEX, WHICH TAKES A LOOK AT MOISTURE STATES OVER
THE LONGER RANGE OF WEEKS TO MONTHS, ALSO SHOWS NEAR NORMAL
MOISTURE STATES.

...RIVER AND ICE CONDITIONS...

THERE HAS BEEN DRASTIC CHANGES IN RIVER AND RIVER ICE CONDITIONS
OVER THE PAST TWO WEEKS. THE ICE WEAKENED QUICKLY IN CENTRAL AND
SOUTHERN PORTIONS OF OUR FORECAST AREA. THE RISES FROM THE
AFOREMENTIONED SNOWMELT ALLOWED MUCH OF THIS ICE TO FLUSH OUT,
ESPECIALLY ALONG THE PENOBSCOT RIVER. SOME THIN ICE, MAINLY 10
INCHES THICK OR LESS, STILL REMAINED ON THE EAST BRANCH OF THE
PENOBSCOT FROM BELOW GRINDSTONE TO MEDWAY. IN FACT, A SMALL ICE
JAM HAD FORMED ON THE LEADING EDGE OF THIS EXISTING ICE COVER NEAR
GRINDSTONE. IT WAS NOT CREATING ANY KNOWN FLOODING CONCERNS AT
THE TIME OF THIS REPORT. THERE WAS ALSO EXISTING THIN ICE COVER ON
THE PISCATAQUIS RIVER, ESPECIALLY THE LOWER REACHES FROM MAXFIELD
DOWN TO HOWLAND. ANOTHER ICE JAM HAD FORMED ON THE PLEASANT RIVER
NEAR MILO THAT WAS CREATING SOME MINOR FIELD FLOODING. THERE WAS
ALSO STILL SOME ICE ON THE PISCATAQUIS IN THE VICINITY OF ABBOT.
FOR THE MOST PART, THESE WATERWAYS AND THEIR TRIBUTARIES WERE
RUNNING HIGH WITH NO SIGNIFICANT FLOODING.

FURTHER NORTH, ALONG THE SAINT JOHN, ALLAGASH, AND AROOSTOOK RIVER
BASINS, THE ICE ALSO WEAKENED SIGNIFICANTLY AS RIVERS ROSE IN
RESPONSE TO SNOWMELT. THERE WAS FINALLY SOME ICE MOVEMENT ON THE
AROOSTOOK BELOW THE CARIBOU DAM, RESULTING IN A JAM AT THE
CARIBOU/FORT FAIRFIELD TOWN LINE. THIS JAM WAS APPROXIMATELY 1.5
MILES LONG AND CREATED FLOODING THAT NECESSITATED THE CLOSURE OF
GRIMES ROAD. UPSTREAM OF THE JAM, FROM PRESQUE ISLE THROUGH
WASHBURN AND WADE, THE ICE COVER WAS VERY WEAK AND LIABLE TO MOVE
AT ANY TIME. DOWNSTREAM OF THE ICE JAM, THE AROOSTOOK WAS COVERED
WITH GRAY ICE THAT LAY IN A SOLID SHEET ALL THE WAY TOWARD THE
INTERNATIONAL BORDER.

ALONG THE SAINT JOHN RIVER, ICE COVER WAS STILL SOLID FROM SAINT
FRANCIS DOWN THROUGH FORT KENT. THE MAINE FOREST SERVICE REPORTED
OPEN WATER FROM MADAWASKA TO GRAND ISLE. FURTHER UPSTREAM, THE ICE
HAD MOVED IN THE DICKEY AREA, RESULTING IN A JAM FROM BIG RAPIDS
DOWN TO DICKEY BRIDGE. THIS WAS CREATING SOME FIELD FLOODING AND
HAD FLOODED A LOCAL ROAD UPSTREAM OF DICKEY.

WITH WARM TEMPERATURES AND SNOWMELT EXPECTED TO LAST THROUGH
FRIDAY, ICE MOVEMENT AND FURTHER JAMS WILL CONTINUE TO BE
POSSIBLE ALONG THE NORTHERN RIVERS.

...IN CONCLUSION...

BASED ON THE AFOREMENTIONED INFORMATION, THE WINTER/SPRING FLOOD
POTENTIAL IS ABOVE NORMAL FOR ALL OF CENTRAL AND DOWNEAST MAINE.
THIS IS MAINLY DUE TO THE THREAT OF OPEN WATER FLOODING. WATERWAYS
IN THESE AREAS, INCLUDING THE PISCATAQUIS, PENOBSCOT, SAINT
CROIX, AND THEIR TRIBUTARIES ARE ALL RUNNING HIGH FROM PLENTIFUL
SNOWMELT RUNOFF. ALTHOUGH A RETURN TO COLDER TEMPERATURES WILL
SLOW SNOWMELT SOMEWHAT, THE TURN TOWARDS A MORE ACTIVE WEATHER
PATTERN KEEPS THE THREAT OF HEAVY AND/OR PROLONGED RAIN AROUND FOR
THE NEXT SEVERAL DAYS. AS SUCH, THE POTENTIAL FOR FLOODING IS
ABOVE NORMAL IN THESE BASINS.

FURTHER NORTH, THE THREAT FOR OPEN WATER FLOODING IS NEAR NORMAL.
ALTHOUGH RIVER FLOWS ARE RUNNING HIGH, AS MENTIONED ABOVE, THE
AMOUNT OF SNOWMELT WILL LESSEN AS WE HEAD THROUGH THE WEEKEND INTO
NEXT WEEK DUE TO COLDER TEMPERATURES. IN FACT, IT WILL EVEN BE
COLD ENOUGH THAT SOME OF PRECIPITATION WILL LIKELY FALL AS SNOW,
CUTTING BACK ON LIQUID PRECIPITATION AMOUNTS. THEREFORE, A NEAR
NORMAL THREAT FOR OPEN WATER FLOODING SEEMS REASONABLE.

THE POTENTIAL FOR FLOODING DUE TO ICE JAMS IS ABOVE NORMAL FOR
NORTHERN MAINE. THIS IS ESPECIALLY TRUE IN THE NEAR TERM AS
TEMPERATURES WILL REMAIN MILD TONIGHT AND FRIDAY. THEREFORE,
SNOWMELT AND RUNOFF WILL CONTINUE TO ALLOW RIVERS TO RISE. WITH
ICE JAMS ALREADY IN PLACE AND THE REMAINING ICE COVER WEAKENING,
THE THREAT FOR FLOODING IS DEFINITELY ABOVE NORMAL THROUGH THE END
OF THE WEEK. THEREAFTER, COLDER TEMPERATURES AND LESSER AMOUNTS OF
SNOWMELT WILL ABATE THE THREAT SOMEWHAT. BUT ANY ICE THAT REMAINS
WILL BE PRONE TO MOVING AND/OR JAMMING SHOULD WARMER TEMPERATURES
AND/OR HEAVY RAIN OCCUR.

IN CENTRAL AND SOUTHERN MAINE, THE THREAT OF ICE JAM FLOODING IS
BELOW NORMAL. MUCH OF THE ICE HAS FLUSHED OUT, ESPECIALLY ON THE
MAINSTEM PENOBSCOT RIVER. WHAT ICE DOES REMAIN, SUCH AS ON THE
EAST BRANCH, THE PISCATAQUIS, AND THE PLEASANT RIVERS IS WEAK AND
NOT PRONE TO SIGNIFICANT ICE JAMMING OR FLOODING. AGAIN, THE
THREAT FOR ICE JAMS WILL EXIST UNTIL THE ICE IS COMPLETELY GONE,
BUT IS BELOW NORMAL FOR MID APRIL.

IT IS IMPORTANT TO REMEMBER THAT VERY HEAVY RAINFALL CAN BRING
FLOODING AT ANY TIME OF THE YEAR, EVEN IN AREAS THAT DON`T HAVE A
SIGNIFICANT SNOWPACK.

THE NEXT WINTER/SPRING FLOOD POTENTIAL OUTLOOK WILL BE ISSUED BY
NWS CARIBOU ON THURSDAY APRIL 30, 2015.

$$

HASTINGS



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.