Flood Potential Outlook
Issued by NWS Gaylord, MI

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FGUS73 KAPX 192200
ESFAPX
MIZ008-015>036-041-042-050000-

PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE GAYLORD MI
500 PM EST THU FEB 19 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:  2/23/2015 - 5/24/2015

                                       :    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 :  10    7   <5   <5   <5   <5
:MANISTEE RIVER
SHERMAN             15.0   16.0   17.0 :  32    9    7   <5   <5   <5
:RIFLE RIVER
STERLING             6.0   11.0   13.0 :  53   52   <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

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: 2/23/2015 - 5/24/2015
LOCATION              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:BOARDMAN RIVER
MAYFIELD--BROWN B     4.3    4.4    4.5    4.8    5.0    5.3    5.5
:AU SABLE RIVER
RED OAK               4.6    4.8    5.2    5.7    6.3    7.0    7.4
:MANISTEE RIVER
SHERMAN              13.6   13.8   14.2   14.6   15.1   15.9   16.7
:RIFLE RIVER
STERLING              4.4    4.6    5.2    6.1    7.3    9.0    9.8
: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: 2/23/2015 - 5/24/2015
LOCATION              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:BOARDMAN RIVER
MAYFIELD--BROWN B     3.6    3.6    3.6    3.6    3.5    3.5    3.5
: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   11.8   11.8   11.8   11.7   11.7
:RIFLE RIVER
STERLING              1.5    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 JANUARY WAS ALSO A
LITTLE BELOW NORMAL...AND THROUGH THE FIRST THREE WEEKS OF FEBRUARY
CONDITIONS HAVE BEEN VERY COLD AND RELATIVELY DRY WITH MOST AREAS
SEEING LESS THAN 75 PERCENT OF NORMAL PRECIPITATION THUS FAR.

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
NEARLY 40 INCHES ACROSS EASTERN UPPER MICHIGAN.  SNOW WATER
EQUIVALENT IS LESS THAN 50 PERCENT OF NORMAL ACROSS MOST AREAS...
LAST YEAR THESE VALUES WERE OVER 90 PERCENT.

STREAMFLOWS HAVE ALSO BEEN RUNNING ABOVE NORMAL AS WELL...WITH
INCREASING ICE COVER DEVELOPING ON AREA RIVERS DUE TO THE RECENT
COLD (WHICH ALSO INCREASES 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...
AN UPDATED SPRING FLOOD OUTLOOK WILL BE ISSUED ON THURSDAY, MARCH
5TH.  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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