Flood Potential Outlook
Issued by NWS Caribou, ME

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5
000
FGUS71 KCAR 060003
ESFCAR
MEZ001>006-010-011-015>017-029>032-080015-

WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE CARIBOU ME
703 PM EST THU MAR 5 2015

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

THIS IS THE FIFTH WINTER/SPRING FLOOD POTENTIAL OUTLOOK FOR
2015...ISSUED BY THE NATIONAL WEATHER SERVICE IN CARIBOU, MAINE.
THE WINTER/SPRING FLOOD POTENTIAL IS FOR NORTHERN, CENTRAL AND
DOWNEAST MAINE FOR THE TWO-WEEK PERIOD FROM MARCH 5 THROUGH MARCH
19, 2015.

THE WINTER/SPRING FLOOD POTENTIAL FOR THE CENTRAL MAINE HIGHLANDS
SOUTH TO THE COAST IS ABOVE NORMAL. FOR NORTHERN MAINE, THE FLOOD
POTENTIAL IS NEAR NORMAL, WITH FAR NORTHERN PORTIONS OF THE
COUNTY LIKELY A BIT BELOW NORMAL FOR EARLY MARCH.

THE POTENTIAL FOR FLOODING DUE TO ICE JAMS IS SLIGHTLY ABOVE
NORMAL FOR ALL OF NORTHERN, CENTRAL, AND DOWNEAST MAINE.

...CLIMATOLOGICAL GUIDANCE...

FEBRUARY WAS A BRUTALLY COLD MONTH ACROSS ALL OF NWS CARIBOU`S
FORECAST AREA. MOST LOCATIONS AVERAGED SOME 10 TO 15 DEGREES
COLDER THAN NORMAL. BANGOR HAD ITS COLDEST MONTH ON RECORD, WHILE
CARIBOU HAD ITS COLDEST FEBRUARY OF ALL TIME.

THANKFULLY, WE`RE FINALLY SEEING SIGNS THAT THIS PROLONGED COLD
PATTERN IS GOING TO CHANGE. MUCH OF THE FORECAST MODEL GUIDANCE IS
SHOWING THAT UPPER LEVEL RIDGING IS GOING TO DEVELOP ACROSS THE
SOUTHEASTERN UNITED STATES, RESULTING IN A WEST-SOUTHWEST OR
WESTERLY FLOW OVER THE NORTHEASTERN UNITED STATES. THIS WILL
FORCE THE POLAR JET STREAM TO LIFT NORTH AND PUSH THE ARCTIC AIR
BACK INTO CANADA. ALTHOUGH IT WILL BE TEMPERED A BIT BY THE DEEP
SNOWPACK, THIS PATTERN CHANGE COMBINED WITH A STRENGTHENING SUN
WILL ALLOW A GRADUAL WARMING TREND IN TEMPERATURES OVER THE NEXT
COUPLE OF WEEKS.

THE OFFICIAL NATIONAL WEATHER SERVICE 8-14 DAY OUTLOOK FOR MID
MARCH SUPPORTS THE ABOVE THINKING AS IT CALLS FOR TEMPERATURES TO
BE ABOVE NORMAL OVER ALL OF MAINE. PRECIPITATION DURING THIS TIME
FRAME IS EXPECTED TO AVERAGE BELOW NORMAL.

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

CONTRARY TO WHAT WE NORMALLY SEE HEADING INTO MARCH, THE DEEPEST
SNOW CURRENTLY LIES ACROSS COASTAL AND DOWNEAST MAINE. THESE AREAS
ARE BLANKETED BY 30 TO 45 INCHES OF SNOW. THIS DECREASES AS ONE
HEADS NORTH INTO THE CENTRAL HIGHLANDS AND SOUTHERN AROOSTOOK
COUNTY. HERE THE SNOW DEPTH IS 20 TO 30 INCHES. FOR THESE AREAS,
THIS AMOUNT OF SNOW IS ABOVE NORMAL AND IS OF COURSE WELL ABOVE
NORMAL DOWNEAST. ACROSS NORTHERN MAINE, WHERE SNOW DEPTHS ARE 12
TO 20 INCHES, SNOW AMOUNTS ARE NEAR NORMAL. PORTIONS OF THE SAINT
JOHN VALLEY ARE PROBABLY EVEN A BIT BELOW NORMAL, WITH FORT KENT
ONLY REPORTING 14 INCHES OF DEPTH AS OF MARCH 4TH.

THE SNOW WATER EQUIVALENT, OR THE AMOUNT OF WATER CONTAINED IN
THE SNOWPACK, IS CLEARLY WELL ABOVE NORMAL OVER DOWNEAST MAINE.
THERE IS 6 TO 9 INCHES OF WATER CONTAINED IN THE SNOW IN THESE
LOCATIONS. THE SWE LESSENS AS ONE HEADS NORTH, WITH THE CENTRAL
HIGHLANDS AND SOUTHERN AROOSTOOK COUNTY REPORTING 5 TO 8 INCHES
OF WATER IN THE PACK, WHICH IS A BIT ABOVE NORMAL. MUCH OF THE
REMAINDER OF THE STATE HAS 4 TO 6 INCHES OF LIQUID EQUIVALENT.
THIS IS FAIRLY CLOSE TO NORMAL. AGAIN, THE EXCEPTION IS ACROSS THE
FAR NORTH WHERE THERE IS 3 TO 5 INCHES OF WATER IN THE SNOWPACK,
WHICH IS A BIT BELOW NORMAL FOR EARLY MARCH.

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

NEAR SURFACE SOIL MOISTURE CONDITIONS, WHICH ARE INDICATIVE OF
NEAR TERM MOISTURE TRENDS, HAVE CONTINUED TO DRY OUT AS FEBRUARY`S
BITTERLY COLD TEMPERATURES HAVE GREATLY LIMITED SNOWMELT. FOR THE
MOST PART, THE SOIL MOISTURE IS NEAR NORMAL IN OUR AREA. THE
EXCEPTION IS DOWNEAST, WHERE MOISTURE STATES ARE SLIGHTLY WETTER
THAN NORMAL DUE TO THE COPIOUS AMOUNTS OF SNOW THAT FELL THROUGH
THE PREVIOUS MONTH.

THE LATEST PALMER DROUGHT SEVERITY INDEX, WHICH TAKES A LOOK AT
MOISTURE STATES OVER THE LONGER RANGE OF WEEKS TO MONTHS, SHOWS
NEAR NORMAL ANTECEDENT MOISTURE CONDITIONS OVER MUCH OF THE PINE
TREE STATE. ONCE AGAIN, THE EXCEPTION IS DOWNEAST WHERE VERY MOIST
CONDITIONS ARE BEING MEASURED.

...RIVER AND ICE CONDITIONS...

RIVER FLOWS HAVE CONTINUED TO SUBSIDE OR HOLD FAIRLY STEADY
THROUGH THE MONTH OWING TO THE VERY COLD TEMPERATURES. THEY ARE
GENERALLY NEAR NORMAL ACROSS THE REGION AS WE TYPICALLY DON`T SEE
MUCH SNOWMELT DURING FEBRUARY ANYWAY. DOWNEAST WATERWAYS MAY AGAIN
BE THE EXCEPTION TO THIS RULE.

ICE THICKNESSES ARE GENERALLY 1 TO 2 FEET ACROSS OUR ENTIRE AREA,
WITH THE COASTAL WATERWAYS AVERAGING CLOSE TO A FOOT. THIS IS
FAIRLY CLOSE TO NORMAL. WHAT IS ABNORMAL IS THE STRENGTH OF THE
ICE, ESPECIALLY IN OUR CENTRAL AND MORE SOUTHERN RIVERS. ALL THE
ICE IS STILL EXCEPTIONALLY STRONG, RATHER THAN HAVING STARTED TO
SHOW SIGNS OF WEAKENING AND ROT. THIS IS LIKELY DUE TO THE
ANOMALOUSLY COLD TEMPERATURES THAT WE EXPERIENCED THROUGH
FEBRUARY. ALTHOUGH THE STRENGTHENING SUN AND MILDER TEMPERATURES
WILL BEGIN TO WORK ON THE RIVER ICE, THEY WILL BE HINDERED BY THE
DEEP AMOUNT OF SNOW THAT STILL LIES ATOP THE ICE.

WE CONTINUE TO MONITOR SEVERAL ICE JAMS THAT REMAIN LOCKED IN
PLACE ALONG MANY OF OUR RIVERS. THESE JAMS INCLUDE A 10-15 MILE
LONG JAM ON THE SAINT JOHN THROUGH SAINT FRANCIS, AS WELL AS ONE
IN MADAWASKA AS REPORTED BY NWS STAFF. THERE ARE ALSO SEVERAL
KNOWN JAMS ON THE AROOSTOOK RIVER, INCLUDING ONE IN WASHBURN
THROUGH CROUSEVILLE, ONE BETWEEN PRESQUE ISLE AND CARIBOU, AND
ANOTHER DOWNSTREAM OF FORT FAIRFIELD. FOR THE CENTRAL RIVERS,
WE`VE NOTED ICE JAMS ON THE PISCATAQUIS IN MAXFIELD, AND THE
PENOBSCOT RIVER NEAR ORONO. THESE JAMS ARE WELL FROZEN IN PLACE
AND HAVE NOT MOVED NOR CAUSED ANY FLOODING ISSUES THROUGH THE
LATER WINTER MONTHS. HOWEVER, THEY WILL BEAR WATCHING AS WE HEAD
THROUGH THE SPRING AS THEY WILL LIKELY SERVE AS A FOCUS FOR BREAK
UP JAMS AND/OR WILL PROVIDE AMPLE ICE DEBRIS AVAILABLE TO JAM
DOWNSTREAM.

...IN CONCLUSION...

BASED ON THE AFOREMENTIONED INFORMATION, THE WINTER/SPRING FLOOD
POTENTIAL IS ABOVE NORMAL FOR ALL OF CENTRAL AND DOWNEAST MAINE,
INCLUDING THE PENOBSCOT, PISCATAQUIS, AND SAINT CROIX RIVER
BASINS. ALTHOUGH RIVER FLOWS ARE NEAR TO A BIT BELOW NORMAL IN
THESE AREAS, ANTECEDENT MOISTURE STATES ARE NEAR TO ABOVE NORMAL,
ESPECIALLY DOWNEAST. THE SNOWPACK AND THE LIQUID WATER EQUIVALENT
CONTAINED THEREIN ARE WELL ABOVE NORMAL. NOW THAT WE ARE IN MARCH
AND EXPECT A WARMING TREND, MELTING SNOW WILL BEGIN TO RAISE WATER
LEVELS. THIS MAY BE SLOW AT FIRST AS THE SNOWPACK WILL BE ABLE TO
ABSORB MELT UNTIL THE PACK RIPENS. HOWEVER, WITH SO MUCH WATER
CONTAINED IN THE SNOW, EVEN WITH NO SIGNIFICANT RAIN EVENTS
EXPECTED IN THE NEAR FUTURE, IT IS STILL MORE LIKELY THAN NORMAL
THAT WE WILL SEE FLOODING IN THESE AREAS THIS SPRING.

ACROSS THE REMAINDER OF THE STATE, THE WINTER/SPRING FLOOD
POTENTIAL IS NEAR NORMAL TO A BIT BELOW NORMAL OVER FAR NORTHERN
MAINE. IN THESE AREAS, THE PRIMARY IMPETUS IN THE NEAR NORMAL
DESIGNATION IS THE NEAR NORMAL SNOW DEPTHS AND AMOUNTS OF WATER
IN THAT PACK. GIVEN THIS IN ADDITION TO THE NEAR NORMAL RIVER
FLOWS, NEAR NORMAL GROUNDWATER LEVELS, AND SOMEWHAT DRY ANTECEDENT
CONDITIONS, A NEAR NORMAL FLOOD THREAT SEEMS REASONABLE. FAR
NORTHERN MAINE HAS A BIT LESS SNOW AND LIQUID EQUIVALENT THAN
WHAT WE`D NORMALLY SEE IN EARLY MARCH, SO THIS AREA`S FLOOD
POTENTIAL IS A BIT BELOW NORMAL.

THE POTENTIAL FOR FLOODING DUE TO ICE JAMS IS SLIGHTLY ABOVE
NORMAL ACROSS THE ENTIRE AREA. THE RIVER ICE IS QUITE THICK, AND
ALTHOUGH IT IS NOT ABNORMALLY SO, IT IS STILL VERY STRONG AND
SOLID. THE WARMING SUN AND MILDER TEMPERATURES WILL HAVE A VERY
HARD TIME WORKING ON THE RIVER ICE, ESPECIALLY SINCE THE ICE IS
STILL COVERED BY AS MUCH AS 30 INCHES OF SNOW IN SOME PLACES.
THEREFORE, THE ICE WILL LIKELY STAY STRONG OVER THE NEXT FEW WEEKS,
MEANING THE ICE JAM THREAT WILL ALSO REMAIN THROUGH MARCH AND INTO
APRIL. THIS MEANS THAT ANY LARGE SCALE RUNOFF EVENTS OVER THE NEXT
MONTH TO 6 WEEKS WILL HAVE THE POTENTIAL TO CAUSE ICE JAM
FLOODING. THIS EASILY JUSTIFIES AN ABOVE NORMAL THREAT.

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 AN
INTERMEDIATE STATEMENT ISSUED BY NWS CARIBOU ON THURSDAY, MARCH
12, 2015, FOLLOWED BY THE REGULAR ISSUANCE ON MARCH 19, 2015.

$$

HASTINGS



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