Flood Potential Outlook
Issued by NWS Gaylord, MI

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FGUS73 KAPX 052041
ESFAPX
MIZ008-015>036-041-042-200000-

PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE GAYLORD MI
341 PM EST THU MAR 5 2015

...SPRING 2015 FLOOD OUTLOOK FOR NORTHERN MICHIGAN...

THE SPRING 2015 FLOOD OUTLOOK FOR NORTHERN MICHIGAN INDICATES A
BELOW AVERAGE PROBABILITY OF FLOODING DUE TO SNOW MELT WITHIN THE
PINE...BOARDMAN...AND AU SABLE RIVER BASINS...NEAR AVERAGE
PROBABILITY WITHIN THE RIFLE RIVER BASIN...AND ABOVE AVERAGE
PROBABILITY WITHIN THE MANISTEE RIVER BASIN.

THIS OUTLOOK COVERS CHIPPEWA AND MACKINAC COUNTIES IN EASTERN UPPER
MICHIGAN WHICH INCLUDES THE PINE RIVER BASIN...AND THE NORTHERN HALF
OF LOWER MICHIGAN ENCOMPASSING THE AU SABLE...BOARDMAN...
CHEBOYGAN... MANISTEE...RIFLE...AND THUNDER BAY RIVER BASINS.

THE FIRST TABLE BELOW LISTS THE PROBABILITIES OF REACHING FLOOD
STAGE (MINOR FLOODING)...AS WELL AS MODERATE AND MAJOR FLOOD LEVELS
FOR THE FIVE FORECAST POINTS WITHIN THE GAYLORD NATIONAL WEATHER
SERVICE OFFICE HYDROLOGIC SERVICE AREA.  THE CURRENT (CS) AND
HISTORICAL (HS) OR NORMAL PROBABILITIES OF EXCEEDING MINOR...
MODERATE...AND MAJOR FLOOD STAGES ARE LISTED FOR THE VALID TIME
PERIOD.

CS VALUES INDICATE THE PROBABILITY OF REACHING A FLOOD CATEGORY
BASED ON CURRENT CONDITIONS.  HS VALUES INDICATE THE PROBABILITY OF
REACHING A FLOOD CATEGORY BASED ON HISTORICAL OR NORMAL CONDITIONS.

WHEN THE VALUE OF CS IS MORE THAN HS...THE PROBABILITY OF EXCEEDING
THAT LEVEL IS HIGHER THAN NORMAL. WHEN THE VALUE OF CS IS LESS THAN
HS...THE PROBABILITY OF EXCEEDING THAT LEVEL IS LOWER THAN NORMAL.

...TABLE 1--PROBABILITIES FOR MINOR...MODERATE AND MAJOR FLOODING...
                    VALID PERIOD:  3/9/2015 - 6/7/2015

                                       :    CURRENT AND HISTORICAL
                                       :     CHANCES OF EXCEEDING
                                       :       FLOOD CATEGORIES
                                       :      AS A PERCENTAGE (%)
                      CATEGORICAL      :
                   FLOOD STAGES (FT)   :   MINOR    MODERATE   MAJOR
LOCATION           MINOR   MOD   MAJOR :  CS   HS   CS   HS   CS   HS
--------           -----  -----  ----- : ---  ---  ---  ---  ---  ---
:BOARDMAN RIVER
MAYFIELD--BROWN B    7.0   99.0   99.0 :  <5   <5   <5   <5   <5   <5
:AU SABLE RIVER
RED OAK              7.0   99.0   99.0 :  <5    7   <5   <5   <5   <5
:MANISTEE RIVER
SHERMAN             15.0   16.0   17.0 :  24   10    6   <5   <5   <5
:RIFLE RIVER
STERLING             6.0   11.0   13.0 :  50   55   <5   <5   <5   <5
:PINE RIVER
RUDYARD             17.0   19.0   99.0 :  <5   <5   <5   <5   <5   <5

LEGEND
CS = CONDITIONAL SIMULATION (CURRENT OUTLOOK)
HS = HISTORICAL SIMULATION
FT = FEET

NOTE THAT WHILE THE MANISTEE RIVER NEAR SHERMAN HAS AN ABOVE AVERAGE
CHANCE OF EXCEEDING FLOOD STAGE OVER THE NEXT 90 DAYS...IT IS STILL A
RELATIVELY LOW PROBABILITY EVENT (1 IN 4 CHANCE OF EXCEEDING FLOOD
STAGE).  AT THE RIFLE RIVER NEAR STERLING...WHILE THE CHANCE OF
EXCEEDING FLOOD STAGE IS NEAR THE HISTORICAL AVERAGE...IT HAS A HIGHER
PROBABILITY OF OCCURRENCE (1 IN 2 CHANCE OF EXCEEDING FLOOD STAGE).

THE NEXT TABLE SHOWS THE CHANCE THAT A PARTICULAR RIVER LOCATION
COULD RISE ABOVE THE LISTED STAGES IN THE SPECIFIED 90 DAY PERIOD
(HIGH FLOW FORECAST):

...TABLE 2--EXCEEDANCE PROBABILITIES...

                               CHANCE OF EXCEEDING STAGES
                                  AT SPECIFIC LOCATIONS
                          VALID PERIOD: 3/9/2015 - 6/7/2015
LOCATION              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:BOARDMAN RIVER
MAYFIELD--BROWN B     4.3    4.4    4.6    4.8    5.0    5.3    5.4
:AU SABLE RIVER
RED OAK               4.6    5.0    5.3    5.6    6.1    6.5    7.0
:MANISTEE RIVER
SHERMAN              13.5   13.8   14.1   14.5   15.0   15.7   16.1
:RIFLE RIVER
STERLING              4.4    4.6    5.1    6.1    6.7    8.1    8.9
:PINE RIVER
RUDYARD               7.6    8.2    9.9   11.3   12.6   13.2   13.7

THE LAST TABLE INDICATES THE CHANCE THAT A PARTICULAR RIVER LOCATION
COULD FALL BELOW THE LISTED STAGES IN THE SPECIFIED 90 DAY PERIOD
(LOW FLOW FORECAST):

...TABLE 3--NONEXCEEDANCE PROBABILITIES...

                            CHANCE OF FALLING BELOW STAGES
                                 AT SPECIFIC LOCATIONS
                          VALID PERIOD: 3/9/2015 - 6/7/2015
LOCATION              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:BOARDMAN RIVER
MAYFIELD--BROWN B     3.5    3.5    3.5    3.5    3.5    3.5    3.4
:AU SABLE RIVER
RED OAK               2.9    2.9    2.9    2.9    2.9    2.9    2.9
:MANISTEE RIVER
SHERMAN              11.8   11.8   11.7   11.7   11.7   11.7   11.5
:RIFLE RIVER
STERLING              1.6    1.5    1.5    1.5    1.5    1.5    1.5
:PINE RIVER
RUDYARD               1.2    1.2    1.2    1.2    1.1    1.1    1.1

SPRING FLOOD OUTLOOKS ARE ROUTINELY ISSUED IN FEBRUARY AND MARCH IN
ORDER TO GIVE ADVANCE NOTICE OF POSSIBLE FLOODING.  THE LONG RANGE
PROBABILISTIC OUTLOOKS GIVEN IN THE ABOVE TABLES CONTAIN FORECAST
VALUES THAT ARE CALCULATED USING MULTIPLE SEASON SCENARIOS FROM 30
OR MORE YEARS OF CLIMATOLOGICAL DATA...AND INCORPORATE CURRENT
RIVER LEVELS...SOIL MOISTURE CONDITIONS...SNOW DEPTH AND SNOW WATER
EQUIVALENT VALUES...AND BOTH 30 AND 90 DAY OUTLOOKS FOR TEMPERATURE
AND PRECIPITATION PROVIDED BY THE NOAA/NWS CLIMATE PREDICTION
CENTER. ACTUAL RIVER CRESTS WILL DIFFER FROM THIS OUTLOOK IF FUTURE
CONDITIONS DIFFER SIGNIFICANTLY FROM FORECAST CONDITIONS...OR IF ICE
JAMS DEVELOP.

...CURRENT CONDITIONS...
ANTECEDENT CONDITIONS IMPACTING FLOOD POTENTIAL ARE SOMEWHAT SIMILAR
TO THOSE OF THE FALL/WINTER MONTHS OF 2013-2014.  ONCE AGAIN WET
CONDITIONS WERE EXPERIENCED ACROSS NORTHERN MICHIGAN DURING THE
SEPTEMBER THROUGH NOVEMBER FALL PERIOD...WITH SAULT STE. MARIE
SETTING A NEW RECORD FOR FALL PRECIPITATION...A RECORD THAT WAS SET
JUST LAST FALL (SEPTEMBER-NOVEMBER 2013).  TRAVERSE CITY ALSO
RECORDED ITS` WETTEST FALL ON RECORD...WITH TOP TEN WETTEST FALLS
FOR GAYLORD AND ALPENA.  THE WET WEATHER ALSO BROUGHT SOIL MOISTURE
TO WELL ABOVE NORMAL LEVELS (MUCH OF EASTERN UPPER/NORTHERN LOWER
WITH SOIL MOISTURE VALUES IN THE UPPER 3 FEET OF THE SOIL PROFILE
ABOVE THE 90TH PERCENTILE).

PRECIPITATION DURING DECEMBER WAS BELOW NORMAL IN MOST AREAS...
GENERALLY BETWEEN 50 AND 100 PERCENT OF NORMAL.  AFTER SETTING A NEW
SNOWFALL RECORD FOR NOVEMBER (65.1 INCHES)...GAYLORD NEARLY SET A
NEW RECORD FOR LEAST SNOWIEST DECEMBER ON RECORD (11.1 INCHES).
ONLY A 3 INCH SNOWFALL ON THE LAST DAY OF THE MONTH PREVENTED THE
RECORD FROM BEING BROKEN.  PRECIPITATION FOR THE WINTER AS A WHOLE
(DECEMBER THROUGH FEBRUARY) WAS DRIER THAN NORMAL ACROSS NORTHERN
LOWER MICHIGAN...AND NEAR NORMAL ACROSS EASTERN UPPER MICHIGAN.
GAYLORD RECORDED ITS` 8TH DRIEST WINTER ON RECORD WITH PRECIPITATION
AROUND 55 PERCENT OF NORMAL.

ONE MAJOR DIFFERENCE BETWEEN THIS WINTER AND LAST WINTER AT THIS
TIME IS THE AMOUNT OF WATER IN THE SNOWPACK.  SNOW DEPTHS CURRENTLY
RANGE FROM 6 TO 12 INCHES ACROSS NORTHEAST LOWER MICHIGAN...10 TO 20
INCHES ACROSS NORTHWEST LOWER MICHIGAN (LOCALLY HIGHER)...AND 15 TO
35 INCHES ACROSS EASTERN UPPER MICHIGAN.  SNOW WATER EQUIVALENT AS
OF THE FIRST WEEK OF MARCH IS NEAR NORMAL ACROSS MOST AREAS EASTERN
UPPER AND NORTHWEST LOWER MICHIGAN...AND BELOW NORMAL OVER THE
CHEBOYGAN AND AU SABLE RIVER BASINS IN NORTHEAST LOWER MICHIGAN.
LAST YEAR...SNOW WATER EQUIVALENT VALUES WERE WELL ABOVE NORMAL
(NEAR THE PEAK OF THE HISTORICAL RECORD).  AS AN EXAMPLE...IN
GAYLORD THE GREATEST SNOW DEPTH THIS SEASON ACTUALLY OCCURRED IN
NOVEMBER (20 INCHES)...WITH THE SNOW DEPTH NOT HAVING EXCEEDED THE
CURRENT VALUE OF 18 INCHES AT ANY POINT DURING THE WINTER MONTHS
(DECEMBER THROUGH FEBRUARY).  LAST YEAR AT THIS TIME THE SNOW DEPTH
IN GAYLORD WAS AT 26 INCHES.

STREAMFLOWS ARE CURRENTLY RUNNING NEAR TO ABOVE NORMAL...WITH
SIGNIFICANT ICE COVER ON AREA RIVERS DUE TO THE RECENT COLD WEATHER
INCREASING THE THREAT FOR ICE JAM DEVELOPMENT.

...WEATHER OUTLOOK...
THE LATEST 30 DAY OUTLOOK FOR MARCH ISSUED BY THE CLIMATE PREDICTION
CENTER...CALLS FOR A HIGHER LIKELIHOOD FOR BELOW NORMAL TEMPERATURES
WITH NO CLEAR SIGNAL REGARDING PRECIPITATION TRENDS.  THE 90 DAY
OUTLOOK FOR THE SPRING MONTHS (MARCH THROUGH MAY)...CALLS FOR EQUAL
PROBABILITIES FOR BELOW...NEAR...OR ABOVE NORMAL TEMPERATURES AND
PRECIPITATION (NO CLEAR SIGNAL NOTED).

...ADDITIONAL INFORMATION...
THIS IS THE FINAL SPRING FLOOD OUTLOOK FOR THIS YEAR.  LONG RANGE
PROBABILISTIC OUTLOOKS SUCH AS THOSE GIVEN IN THE ABOVE TABLES ARE
ISSUED DURING THE LAST WEEK OF EACH MONTH THROUGHOUT THE YEAR.

VISIT OUR WEB SITE AT WATER.WEATHER.GOV/AHPS2/INDEX.PHP?WFO=APX (ALL
LOWER CASE) FOR MORE RIVER INFORMATION...INCLUDING GRAPHS OF THE
PROBABILISTIC INFORMATION GIVEN IN THE ABOVE TABLES...AS WELL AS THE
LATEST OBSERVED CONDITIONS ON NORTHERN MICHIGAN STREAMS.

$$

JPB



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