Flood Potential Outlook
Issued by NWS Gaylord, MI

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020
FGUS73 KAPX 161852
ESFAPX
MIC001-007-009-011-019-029-031-033-039-047-051-055-069-079-089-097-
101-113-119-129-135-137-141-143-165-181852-

Probabilistic Hydrologic Outlook
National Weather Service Gaylord MI
152 PM EST THU FEB 16 2017

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

THE SPRING 2017 FLOOD OUTLOOK FOR NORTHERN MICHIGAN INDICATES A BELOW
AVERAGE PROBABILITY OF FLOODING DUE TO SNOW MELT WITHIN MAJOR EASTERN
UPPER AND NORTHERN LOWER MICHIGAN RIVER BASINS.

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...MANISTEE...
RIFLE...AND TOBACCO 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
SIX FORECAST POINTS WITHIN THE GAYLORD NATIONAL WEATHER SERVICE
OFFICE HYDROLOGIC SERVICE AREA.  THE CURRENT (CS) AND HISTORICAL (HS)
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:  02/19/2017 - 05/20/2017

                                       :    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
--------           -----  -----  ----- : ---  ---  ---  ---  ---  ---
:MANISTEE RIVER
SHERMAN             15.0   16.0   17.0 :  20   11   <5   <5   <5   <5
: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    9   <5   <5   <5   <5
:RIFLE RIVER
STERLING             6.0   11.0   13.0 :  41   57   <5   <5   <5   <5
:PINE RIVER
RUDYARD             17.0   19.0   99.0 :  <5   <5   <5   <5   <5   <5
:TOBACCO RIVER
BEAVERTON           12.0   14.0   99.0 :  <5   <5   <5   <5   <5   <5

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

DEPARTURE FROM NORMAL OF REACHING FLOOD STAGE IS THE DIFFERENCE
BETWEEN THE CURRENT PROJECTED CHANCE FOR REACHING FLOOD STAGE (CS)
AND THE CLIMATIC NORMAL (HS).  FOR EXAMPLE...THE RIFLE RIVER NEAR
STERLING....WITH A FLOOD STAGE OF 6 FEET...HAS A 41 PERCENT CHANCE OF
REACHING OR EXCEEDING FLOOD STAGE WHICH IS 16 PERCENTAGE POINTS BELOW
NORMAL. DURING THE 90 DAY PERIOD LISTED...THE NORMAL PROBABILITY OF
THE RIFLE RIVER NEAR STERLING REACHING FLOOD STAGE IS 57 PERCENT.

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--EXCEEDENCE PROBABILITIES

                               CHANCE OF EXCEEDING STAGES
                                  AT SPECIFIC LOCATIONS
                          VALID PERIOD: 02/19/2017 - 05/20/2017
LOCATION              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:MANISTEE RIVER
SHERMAN              13.4   13.6   14.0   14.4   14.7   15.3   15.6
:BOARDMAN RIVER
MAYFIELD--BROWN B     4.1    4.2    4.3    4.6    4.7    4.9    5.2
:AU SABLE RIVER
RED OAK               4.1    4.3    4.6    5.0    5.4    6.0    6.4
:RIFLE RIVER
STERLING              3.9    4.3    4.7    5.6    6.8    8.0    8.5
:PINE RIVER
RUDYARD               6.6    7.0    8.4   10.0   11.8   12.6   13.3
:TOBACCO RIVER
BEAVERTON             5.1    5.6    6.2    6.8    7.3    8.4    9.0

CURRENT FORECASTS SUGGEST PROBABILITIES OF EXCEEDING FLOOD STAGE ARE
LESS THAN 50 PERCENT ON THE RIFLE RIVER NEAR STERLING...LESS THAN 25
PERCENT ON THE MANISTEE RIVER NEAR SHERMAN...AND LESS THAN 5 PERCENT
ELSEWHERE.

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: 02/19/2017 - 05/20/2017
LOCATION              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:MANISTEE RIVER
SHERMAN              12.1   12.1   12.0   12.0   11.8   11.7   11.6
:BOARDMAN RIVER
MAYFIELD--BROWN B     3.6    3.5    3.5    3.5    3.5    3.5    3.4
:AU SABLE RIVER
RED OAK               3.0    3.0    3.0    3.0    2.9    2.9    2.8
:RIFLE RIVER
STERLING              2.2    2.2    2.0    1.9    1.8    1.7    1.6
:PINE RIVER
RUDYARD               1.3    1.3    1.2    1.2    1.1    1.1    1.1
:TOBACCO RIVER
BEAVERTON             2.5    2.5    2.4    2.4    2.3    2.3    2.3


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...
PERSISTENT MILD CONDITIONS RESULTED IN ONE OF THE WARM FALL SEASONS
(SEPTEMBER THROUGH NOVEMBER) ON RECORD AT SEVERAL NORTHERN MICHIGAN
LOCATIONS...INCLUDING SAULT STE. MARIE...TRAVERSE CITY AND GAYLORD.
FALL PRECIPITATION WAS NEAR NORMAL ACROSS EASTERN UPPER MICHIGAN AND
SLIGHTLY BELOW NORMAL ACROSS NORTHERN LOWER MICHIGAN.  THE LACK OF
COLD AIR ALSO RESULTED IN A SLOW START TO THE SNOW SEASON...THOUGH
DECEMBER MORE THAN MADE UP FOR THAT ESPECIALLY ACROSS THE TRADITIONAL
LAKE SUPERIOR AND LAKE MICHIGAN SNOW BELTS.  GAYLORD RECORDED ITS
SNOWIEST DECEMBER ON RECORD (60.1 INCHES)...WITH TOP TEN SNOWIEST
DECEMBERS AT SAULT STE. MARIE AND HOUGHTON LAKE.  JANUARY WAS ALSO
MILD WITH A PROLONGED JANUARY THAW DURING THE LATTER HALF OF THE
MONTH...ALONG WITH ABOVE NORMAL PRECIPITATION ESPECIALLY ACROSS
NORTHERN LOWER.  THUS FAR THROUGH THE FIRST HALF OF FEBRUARY...
TEMPERATURES ARE RUNNING 2 TO 4 DEGREES ABOVE NORMAL...WHILE
PRECIPITATION THUS FAR HAS BEEN ABOVE NORMAL (MORE THAN 150 PERCENT
OF NORMAL ACROSS CHIPPEWA COUNTY AND MUCH OF NORTHERN LOWER MICHIGAN
NORTH OF THE M-72 CORRIDOR).  THE ONLY SIGNIFICANT PRECIPITATION
DEFICITS FOR FEBRUARY HAVE OCCURRED ACROSS MANISTEE/BENZIE/LEELANAU
COUNTIES...WHERE PRECIPITATION HAS BEEN LESS THAN 75 PERCENT NORMAL.

SOIL MOISTURE ACROSS NORTHERN MICHIGAN IS NEAR NORMAL.

CURRENT SNOW DEPTH ACROSS THE AREA RANGES FROM 10 INCHES TO MORE
THAN TWO FEET ACROSS EASTERN UPPER WITH HIGHEST TOTALS SURROUNDING
WHITEFISH BAY...AND FROM 12 TO 18 INCHES ACROSS THE HIGHER TERRAIN
OF NORTHWEST/NORTH CENTRAL LOWER MICHIGAN...TO PRETTY MUCH NO SNOW
COVER OVER THE TOBACCO RIVER BASIN AND ADJACENT TO SAGINAW BAY.
SNOW WATER EQUIVALENT IN THE SNOWPACK WAS NEAR NORMAL ACROSS THE
HIGHER TERRAIN OF NORTHERN LOWER WHEN SNOW DEPTH IS GREATEST...AND
ABOVE NORMAL OVER PARTS OF CHIPPEWA COUNTY.  SNOW WATER EQUIVALENT
IS BELOW NORMAL ELSEWHERE (CONDITIONAL ON SNOW COVER).

STREAMFLOWS ON AREA RIVERS WERE GENERALLY NEAR NORMAL THOUGH ICE
COVER HAS BEEN RESULTING IN FLUCTUATIONS ON SOME RIVER CHANNELS.

...WEATHER OUTLOOK...
THE LATEST 6 TO 10 DAY OUTLOOK FROM THE CLIMATE PREDICTION CENTER
(CPC) SHOWS A STRONG SIGNAL FOR ABOVE NORMAL TEMPERATURES ACROSS
THE GREAT LAKES REGION IN THE FEBRUARY 21-25 TIME FRAME...ALONG
WITH A CHANCE FOR ABOVE NORMAL PRECIPITATION. THE CPC 30 DAY OUTLOOK
FOR THE MONTH OF MARCH SHOWS NO SIGNIFICANT TREND IN FORECAST
TEMPERATURES OR PRECIPITATION.  THE 90 DAY OUTLOOK FOR THE SPRING
(MARCH THROUGH MAY) INDICATES A HIGHER PROBABILITY OF BOTH ABOVE
NORMAL TEMPERATURES AND PRECIPITATION.

...ADDITIONAL INFORMATION...
AN UPDATED SPRING FLOOD OUTLOOK WILL BE ISSUED ON THURSDAY MARCH 2ND.
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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