Friday, March 14, 2014

Winter and Spring Flood Potential Outlook issued on March 13th

000
FGUS71 KCAR 131818
ESFCAR

WINTER/SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE CARIBOU ME
218 PM EDT THU MAR 13 2014

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

THIS IS THE SIXTH WINTER/SPRING FLOOD POTENTIAL OUTLOOK FOR
2014...ISSUED BY THE NATIONAL WEATHER SERVICE IN CARIBOU, MAINE.
THE WINTER/SPRING FLOOD POTENTIAL IS FOR NORTHERN, CENTRAL AND
DOWNEAST MAINE FOR THE ONE WEEK PERIOD FROM MARCH 13 TO MARCH 20,
2014.

THE WINTER/SPRING FLOOD POTENTIAL FOR NORTHERN AND CENTRAL AND
MAINE IS NEAR NORMAL THROUGH THE NEAR TERM, THOUGH IT IS ABOVE
NORMAL THROUGH THE LONG TERM. LIKEWISE, THE POTENTIAL FOR FLOODING
DUE TO ICE JAMS IS ALSO NEAR NORMAL IN THE SHORT TERM BUT ABOVE
NORMAL GOING FORWARD THROUGH SPRING.

FOR DOWNEAST MAINE, THE WINTER/SPRING FLOOD POTENTIAL IS NEAR NORMAL
THROUGH BOTH THE SHORT AND LONG TERMS, AS IS THE POTENTIAL FOR
FLOODING DUE TO ICE JAMS.

...CLIMATOLOGICAL GUIDANCE...

UP UNTIL THE CURRENT STORM, THE REGION HAD BEEN CONTINUING TO SEE
COLD AND DRY CONDITIONS THROUGH THE FIRST PART OF MARCH. THE SECOND
WEEK HASN'T BEEN QUITE AS DRASTICALLY COLD AS THE FIRST WEEK;
AVERAGE DAILY TEMPERATURES HAVE BEEN WITHIN 10 DEGREES OF NORMAL
INSTEAD OF 10 TO 20 DEGREES BELOW NORMAL AS WE HAD SEEN EARLIER.
UNFORTUNATELY, THE BITTER COLD HAS RESUMED ACROSS THE REGION TODAY.
HOWEVER, ANOTHER WARM UP IS EXPECTED THIS WEEKEND, ALONG WITH THE
CHANCE FOR RAIN AND SNOW. THIS MILD AIR WILL BE VERY BRIEF WITH COLD
AIR SETTLING BACK IN BY MONDAY. ALSO, THE DEEP SNOWPACK WILL READILY
SOAK UP ANY LIQUID PRECIPITATING. CURRENT INDICATIONS ARE THAT
COLDER THAN NORMAL CONDITIONS WILL PREVAIL THROUGH AT LEAST THE
MIDDLE OF NEXT WEEK. IN ADDITION, THE PATTERN LOOKS TO REMAIN ACTIVE
OVER THE NEXT SEVERAL DAYS WITH STORM SYSTEMS TO AFFECT THE REGION
EVERY FEW DAYS. THE OFFICIAL NATIONAL WEATHER SERVICE 6 TO 10 DAY
FORECAST MATCHES THIS THINKING WELL, CALLING FOR COLDER THAN NORMAL
TEMPERATURES AND ABOVE NORMAL PRECIPITATION FOR ALL OF NORTHERN AND
EASTERN MAINE.

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

SNOW DEPTH AND THE SNOW WATER EQUIVALENT INCREASED SUBSTANTIALLY
FROM THIS STORM, AND AS SUCH THEY ARE NOW ABOVE NORMAL FOR MID MARCH
ACROSS MUCH OF THE STATE. UNFORTUNATELY, THE STATEWIDE MEASUREMENTS
WERE TAKEN PRIOR TO THE STORM, AND GIVEN THAT THE SNOW IS STILL
ONGOING, THE EXACT DEPTHS ARE CURRENTLY UNKNOWN IN MOST LOCATIONS.

THAT BEING SAID, IT IS LIKELY THAT MUCH OF NORTHERN AND CENTRAL
MAINE IS NOW COVERED BY 30 TO 45 INCHES OF SNOW. THESE AMOUNTS ARE
ABOVE NORMAL FOR MID MARCH. THE SNOWPACK DECREASES SUBSTANTIALLY AS
YOU HEAD SOUTHWARD INTO DOWNEAST MAINE AND ALONG THE COAST, WHERE
NOT ONLY WAS THE ANTECEDENT SNOWPACK LESS, THEY ALSO RECEIVED LESS
SNOWFALL FROM THIS STORM DUE TO A WINTRY MIX OF PRECIPITATION. SNOW
DEPTHS IN THESE AREAS ARE LIKELY 8 TO 20 INCHES, WHICH IS NEAR 
NORMAL.

THE SNOW WATER EQUIVALENT, OR THE AMOUNT OF WATER CONTAINED IN THE
SNOWPACK, IS ALSO ABOVE NORMAL OVER NORTHERN AND CENTRAL MAINE.
ROUGHLY 6 TO 8 INCHES OF WATER IS LIKELY CONTAINED IN THE PACK, WITH
ISOLATED AMOUNTS AROUND 9 INCHES ACROSS THE HIGHER ELEVATIONS.
DOWNEAST MAINE GENERALLY HAS 4 TO 7 INCHES OF WATER IN THE SNOW THAT
COVERS THE GROUND. THIS IS NEAR NORMAL.

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

WITH THE COLD WEATHER WE'VE EXPERIENCED OVER THE PAST SEVERAL
WEEKS, THERE HAS BEEN VERY LITTLE RUNOFF FROM EITHER RAIN OR
SNOWMELT. ANY LIQUID RUNOFF ACROSS DOWNEAST MAINE FROM THE CURRENT
STORM SYSTEM WAS LIKELY ABSORBED BY THE SNOWPACK. THEREFORE, SOIL
MOISTURE STATES ARE MAINLY NEAR NORMAL, THOUGH NORTHERN MAINE IS
STILL SHOWING SLIGHTLY WETTER THAN NORMAL SOIL MOISTURE. THE LONGER
TERM PALMER DROUGHT INDEX RELEASED MARCH 8TH SHOWS ALL OF NORTHERN
AND EASTERN MAINE NEAR NORMAL.

...RIVER AND ICE CONDITIONS...

AS MENTIONED PREVIOUSLY, ANY LIQUID FROM THE ONGOING STORM
SHOULD BE ABSORBED BY THE SNOWPACK, LIMITING ANY RUNOFF OVER THE
PAST 24 HOURS. PRIOR TO THE PAST COUPLE OF DAYS, TEMPERATURES HAD 
REMAINED COLD ENOUGH OVER THE PAST SEVERAL WEEKS TO LIMIT ANY
SIGNIFICANT SNOWMELT AND KEEP ANY PRECIPITATION IN THE FORM OF SNOW.
WHILE A WARM UP IS EXPECTED THROUGH THE WEEKEND, THE MILD SPELL WILL
BE BRIEF. ANY RAIN OR SNOWMELT WILL EASILY BE CONTAINED WITHIN THE
SNOWPACK, SO LITTLE TO NO RUNOFF IS EXPECTED OVER THE NEXT SEVERAL
DAYS. THEREFORE, RIVER FLOWS ARE EXPECTED TO CONTINUE TO HOLD STEADY
OR EVEN FALL SLIGHTLY OVER THE NEXT SEVERAL DAYS.

THE ICE ALONG THE NORTHERN WATERWAYS, INCLUDING THE ALLAGASH,
SAINT JOHN, AND AROOSTOOK RIVERS, CONTINUES TO STRENGTHEN.
THICKNESSES IN THESE RIVERS IS GENERALLY 1.5 TO AROUND 2 FEET
THICK, WITH THE UPPER REACHES PERHAPS APPROACHING 30 INCHES IN SPOTS.
THIS IS GENERALLY NORMAL FOR THIS TIME OF YEAR. WITH GENERALLY COLD
WEATHER TO CONTINUE, THE ICE WILL LIKELY CONTINUE TO HOLD STEADY OR
EVEN SLOWLY BUILD OVER THE NEXT COUPLE OF WEEKS.

FURTHER SOUTH, THE CENTRAL RIVERS SUCH AS THE PISCATAQUIS AND
PENOBSCOT GENERALLY HAVE 1 TO 1.5 FEET OF ICE. THE LOWER REACHES
OF THESE RIVERS WHICH EXPERIENCED BREAKUP DURING THE JANUARY THAW
HAVE 6 TO 10 INCHES OF ICE. HOWEVER, SOME STRETCHES, EVEN THOSE IN
THE UPPER REACHES, ARE PARTIALLY OPEN WITH FAIRLY THIN AND/OR WEAK
ICE. FAR DOWNEAST RIVERS HAVE 1 FOOT OF ICE OR LESS. THESE CENTRAL
AND SOUTHERN WATERWAYS HAVE LESS ICE THAN NORMAL FOR MID MARCH.
LIKE THE NORTHERN RIVERS, THE CONTINUED COLD WILL ALLOW THE ICE IN
THESE AREAS TO AT LEAST HOLD STEADY OVER THE NEXT COUPLE OF WEEKS,
IF NOT BUILD SOMEWHAT.

SEVERAL JAMS REMAIN LOCKED IN PLACE ACROSS CARIBOU'S FORECAST
AREA. THESE INCLUDE BUT ARE NOT LIMITED TO ICE JAMS ALONG THE
SAINT JOHN RIVER UPSTREAM OF FORT KENT, THE EAST BRANCH OF THE
PENOBSCOT RIVER DOWNSTREAM OF GRINDSTONE, THE PENOBSCOT RIVER NEAR
WINN, THE PISCATAQUIS RIVER UPSTREAM OF HOWLAND, AND THE
KENDUSKEAG STREAM IN DOWNTOWN BANGOR. THESE JAMS ARE NOW WELL
FROZEN IN PLACE AND ARE NOT EXPECTED TO MOVE OVER THE NEXT COUPLE
OF WEEKS. HOWEVER, SHOULD A PROLONGED WARM UP OCCUR, ESPECIALLY
ACCOMPANIED BY SIGNIFICANT RAINFALL, THESE EXISTING JAMS WILL
LIKELY SERVE AS A FOCUS FOR ADDITIONAL JAMMING AND POTENTIAL
FLOODING. IN ADDITION, THE ICE ALONG THE UNBROKEN STRETCHES IS
VERY WELL ESTABLISHED AND WHILE IT WILL TAKE MAJOR RIVER RISES TO
BREAK IT UP, IT WILL BE MORE SUSCEPTIBLE TO CAUSING JAMMING ONCE
IT DOES RELEASE.

...IN CONCLUSION...

BASED ON THE AFOREMENTIONED INFORMATION, THE SHORT-TERM
WINTER/SPRING FLOOD POTENTIAL IS NEAR NORMAL FOR ALL OF NORTHERN AND
CENTRAL MAINE.  RIVER FLOWS, GROUNDWATER LEVELS, AND ANTECEDENT
MOISTURE ARE ALL NEAR NORMAL. SNOW DEPTHS AND SNOW WATER EQUIVALENTS
ARE ABOVE NORMAL IN THESE AREAS. HOWEVER, THE CURRENT WARM UP AND
RAIN FORECASTED FOR THE UPCOMING WEEKEND IS NOT EXPECTED TO PRODUCE
ENOUGH RUNOFF TO BRING A FLOODING THREAT. WITH COLD TEMPERATURES TO
RESUME NEXT WEEK AND HOLD INTO LATE MARCH, IT LOOKS LIKE THE FLOOD
POTENTIAL WILL REMAIN NEAR NORMAL. IT SHOULD BE NOTED, THOUGH, THAT
THE INCREASED SNOWPACK AND SNOW WATER EQUIVALENT WILL LIKELY HOLD
INTO APRIL AS CONDITIONS REMAIN COLD. THEREFORE, IN THE LONGER TERM,
THE FLOOD POTENTIAL IS ABOVE NORMAL FOR NORTHERN AND CENTRAL MAINE
AS THE SNOWPACK WILL BE EXTENSIVE HEADING INTO THE SPRING MELT.

FOR DOWNEAST MAINE, SNOW DEPTHS AND THE AMOUNT OF WATER CONTAINED IN
THE PACK ARE NEAR NORMAL. WITH GENERALLY COLD WEATHER INTERSPERSED
WITH BRIEF MILD CONDITIONS EXPECTED, BOTH THE SHORT AND LONG TERM
FLOODING POTENTIAL IS NEAR NORMAL.

THE POTENTIAL FOR ICE JAM FLOODING IS ALSO NEAR NORMAL FOR NORTHERN
AND CENTRAL THROUGH THE NEAR TERM. ALTHOUGH ICE JAMS EXIST ALONG
SEVERAL RIVERS IN CARIBOU'S FORECAST AREA, THESE JAMS ARE LOCKED IN
PLACE. THE ICE IS WELL ESTABLISHED ON THE SAINT JOHN, AROOSTOOK, AND
ALLAGASH WATERWAYS. ICE THICKNESSES ACROSS THE REGION ARE GENERALLY
1 TO AS MUCH AS 3 FEET. AS MENTIONED EARLIER, THE NEAR-TERM WARM UP
WILL NOT BE SUBSTANTIAL ENOUGH TO MOVE ANY OF THIS ICE. WITH ARCTIC
AIR TO RETURN BY EARLY NEXT WEEK AND LINGER INTO LATE MARCH, NO ICE
BREAKUP OR JAMMING IS EXPECTED THROUGH THE NEXT COUPLE OF WEEKS. IN
FACT, THE COLD AIR WILL ALLOW RIVER ICE TO AT LEAST HOLD FAIRLY
STEADY IF NOT CONTINUE TO SLOWLY BUILD. THIS MEANS WE WILL LIKELY
ENTER LATE MARCH WITH A SUBSTANTIAL AMOUNT OF RIVER ICE,
ESPECIALLY ACROSS THE NORTH. AS SUCH, THERE IS AN ABOVE NORMAL THREAT
FOR ICE JAM FLOODING THROUGH THE LONGER TERM. THE RIVERS WILL NEED
TO BE MONITORED CLOSELY AS WE HEAD THROUGH SPRING.

DOWNEAST RIVERS, MEANWHILE, ARE GENERALLY COVERED WITH LESS THAN
NORMAL ICE. WITH NEAR NORMAL SNOWPACK AND SNOW WATER EQUIVALENT, THE
THREAT FOR ICE JAM FLOODING IS NEAR NORMAL FOR MID MARCH.

IT IS IMPORTANT TO REMEMBER THAT VERY HEAVY RAINFALL CAN BRING
FLOODING AT ANY TIME OF THE YEAR, EVEN IN AREAS THAT HAVE LITTLE
OR NO SNOW ON THE GROUND.

THE NEXT WINTER/SPRING FLOOD POTENTIAL OUTLOOK WILL BE ISSUED BY
NWS CARIBOU ON THURSDAY, MARCH 20, 2014.

$$

HASTINGS

0 Comments:

Post a Comment

<< Home